Ultrasonic transducer for extreme temperature environments

DOEpatents

Light, Glenn M.; Cervantes, Richard A.; Alcazar, David G.

1993-03-23

An ultrasonic piezoelectric transducer that is operable in very high and very low temperatures. The transducer has a dual housing structure that isolates the expansion and contraction of the piezoelectric element from the expansion and contraction of the housing. Also, the internal components are made from materials having similar coefficients of expansion so that they do not interfere with the motion of the piezoelectric element.

In-plane ultrasonic velocity measurement of longitudinal and shear waves in the machine direction with transducers in rotating wheels

DOEpatents

Hall, M.S.; Jackson, T.G.; Knerr, C.

1998-02-17

An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the MD and CD, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web. 37 figs.

In-plane ultrasonic velocity measurement of longitudinal and shear waves in the machine direction with transducers in rotating wheels

DOEpatents

Hall, Maclin S.; Jackson, Theodore G.; Knerr, Christopher

1998-02-17

An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the MD and CD, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web.

Systematic study of high-frequency ultrasonic transducer design for laser-scanning photoacoustic ophthalmoscopy

PubMed Central

Ma, Teng; Zhang, Xiangyang; Chiu, Chi Tat; Chen, Ruimin; Kirk Shung, K.; Zhou, Qifa; Jiao, Shuliang

2014-01-01

Abstract. Photoacoustic ophthalmoscopy (PAOM) is a high-resolution in vivo imaging modality that is capable of providing specific optical absorption information for the retina. A high-frequency ultrasonic transducer is one of the key components in PAOM, which is in contact with the eyelid through coupling gel during imaging. The ultrasonic transducer plays a crucial role in determining the image quality affected by parameters such as spatial resolution, signal-to-noise ratio, and field of view. In this paper, we present the results of a systematic study on a high-frequency ultrasonic transducer design for PAOM. The design includes piezoelectric material selection, frequency selection, and the fabrication process. Transducers of various designs were successfully applied for capturing images of biological samples in vivo. The performances of these designs are compared and evaluated. PMID:24441942

Systematic study of high-frequency ultrasonic transducer design for laser-scanning photoacoustic ophthalmoscopy.

PubMed

Ma, Teng; Zhang, Xiangyang; Chiu, Chi Tat; Chen, Ruimin; Kirk Shung, K; Zhou, Qifa; Jiao, Shuliang

2014-01-01

Photoacoustic ophthalmoscopy (PAOM) is a high-resolution in vivo imaging modality that is capable of providing specific optical absorption information for the retina. A high-frequency ultrasonic transducer is one of the key components in PAOM, which is in contact with the eyelid through coupling gel during imaging. The ultrasonic transducer plays a crucial role in determining the image quality affected by parameters such as spatial resolution, signal-to-noise ratio, and field of view. In this paper, we present the results of a systematic study on a high-frequency ultrasonic transducer design for PAOM. The design includes piezoelectric material selection, frequency selection, and the fabrication process. Transducers of various designs were successfully applied for capturing images of biological samples in vivo. The performances of these designs are compared and evaluated.

Pitch-catch only ultrasonic fluid densitometer

DOEpatents

Greenwood, M.S.; Harris, R.V.

1999-03-23

The present invention is an ultrasonic fluid densitometer that uses a material wedge and pitch-catch only ultrasonic transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface. 6 figs.

Pitch-catch only ultrasonic fluid densitometer

DOEpatents

Greenwood, Margaret S.; Harris, Robert V.

1999-01-01

The present invention is an ultrasonic fluid densitometer that uses a material wedge and pitch-catch only ultrasonic transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.

Overview of the ultrasonic instrumentation research in the MYRRHA project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dierckx, M.; Leysen, W.; Van Dyck, D.

The Belgian Nuclear Research Centre SCK.CEN is in the process of developing MYRRHA, a new generation IV fast flux research reactor to replace the aging BR2. MYRRHA is conceptualized as an accelerator driven system cooled with lead bismuth eutectic mixture (LBE). As LBE is opaque to visual light, ultrasonic measurement techniques are employed as the main technology to provide feedback where needed. This paper we will give an overview of the R and D at SCK.CEN with respect to ultrasonic instrumentation in heavy liquid metals. High temperature ultrasonic transducers are deployed into the reactor to generate and receive the requiredmore » ultrasonic signals. The ultrasonic waves are generated and sensed by means of a piezo-electric disc at the heart of the transducer. The acoustic properties of commonly used piezo-electric materials match rather well with the acoustic properties of heavy liquid metals, simplifying the design and construction of high bandwidth ultrasonic transducers for use in heavy liquid metals. The ultrasonic transducers will operate in a liquid metal environment, where radiation and high temperature limit the choice of materials for construction. Moreover, the high surface tension of the liquid metal hinders proper wetting of the transducer, required for optimal transmission and reception of the ultrasonic waves. In a first part of the paper, we will discuss the effect of these parameters on the performance of the overall ultrasonic system. In the second part of the paper, past, present and future ultrasonic experiments in LBE will be reviewed. We will show the results of an experiment where a transducer is scanned near the free surface of an LBE pool to render ultrasonic images of objects submerged in the heavy liquid metal. Additionally, the preliminary results of an ongoing experiment that measures the evolution of LBE wetting on different types of metals and various surface conditions will be reported. The evolution of wetting is an important parameter to assess the performance of ultrasonic systems that are submerged in LBE over longer time periods. In the last part we will briefly present the overall design of the two main ultrasonic systems that will be deployed in MYRRHA: the ultrasonic fuel identification system and the ultrasonic lost fuel localization system. (authors)« less

Method and system of measuring ultrasonic signals in the plane of a moving web

DOEpatents

Hall, Maclin S.; Jackson, Theodore G.; Wink, Wilmer A.; Knerr, Christopher

1996-01-01

An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like. In addition to velocity measurements of ultrasonic signals in the plane of the web in the machine direction, MD, and a cross direction, CD, generally perpendicular to the direction of the traveling web, therefor, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web.

Method and system of measuring ultrasonic signals in the plane of a moving web

DOEpatents

Hall, M.S.; Jackson, T.G.; Wink, W.A.; Knerr, C.

1996-02-27

An improved system for measuring the velocity of ultrasonic signals within the plane of moving web-like materials, such as paper, paperboard and the like is disclosed. In addition to velocity measurements of ultrasonic signals in the plane of the web in the machine direction, MD, and a cross direction, CD, generally perpendicular to the direction of the traveling web, therefore, one embodiment of the system in accordance with the present invention is also adapted to provide on-line indication of the polar specific stiffness of the moving web. In another embodiment of the invention, the velocity of ultrasonic signals in the plane of the web are measured by way of a plurality of ultrasonic transducers carried by synchronously driven wheels or cylinders, thus eliminating undue transducer wear due to any speed differences between the transducers and the web. In order to provide relatively constant contact force between the transducers and the webs, the transducers are mounted in a sensor housings which include a spring for biasing the transducer radially outwardly. The sensor housings are adapted to be easily and conveniently mounted to the carrier to provide a relatively constant contact force between the transducers and the moving web. 37 figs.

Nuclear Radiation Tolerance of Single Crystal Aluminum Nitride Ultrasonic Transducer

NASA Astrophysics Data System (ADS)

Reinhard, Brian; Tittmann, Bernhard R.; Suprock, Andrew

Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models, (Rempe et al., 2011; Kazys et al., 2005). These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The irradiation is also supported by a multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET ASI) program. The results from this irradiation, which started in February 2014, offer the potential to enable the development of novel radiation tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. Hence, results from this irradiation offer the potential to bridge the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, very encouraging results have been attained as several transducers have continued to operate under irradiation. The irradiation is ongoing and will continue to approximately mid-2015.

Non-destructive evaluation method employing dielectric electrostatic ultrasonic transducers

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

2003-01-01

An acoustic nonlinearity parameter (.beta.) measurement method and system for Non-Destructive Evaluation (NDE) of materials and structural members novelly employs a loosely mounted dielectric electrostatic ultrasonic transducer (DEUT) to receive and convert ultrasonic energy into an electrical signal which can be analyzed to determine the .beta. of the test material. The dielectric material is ferroelectric with a high dielectric constant .di-elect cons.. A computer-controlled measurement system coupled to the DEUT contains an excitation signal generator section and a measurement and analysis section. As a result, the DEUT measures the absolute particle displacement amplitudes in test material, leading to derivation of the nonlinearity parameter (.beta.) without the costly, low field reliability methods of the prior art.

Single Transducer Ultrasonic Imaging Method that Eliminates the Effect of Plate Thickness Variation in the Image

NASA Technical Reports Server (NTRS)

Roth, Don J.

1996-01-01

This article describes a single transducer ultrasonic imaging method that eliminates the effect of plate thickness variation in the image. The method thus isolates ultrasonic variations due to material microstructure. The use of this method can result in significant cost savings because the ultrasonic image can be interpreted correctly without the need for machining to achieve precise thickness uniformity during nondestructive evaluations of material development. The method is based on measurement of ultrasonic velocity. Images obtained using the thickness-independent methodology are compared with conventional velocity and c-scan echo peak amplitude images for monolithic ceramic (silicon nitride), metal matrix composite and polymer matrix composite materials. It was found that the thickness-independent ultrasonic images reveal and quantify correctly areas of global microstructural (pore and fiber volume fraction) variation due to the elimination of thickness effects. The thickness-independent ultrasonic imaging method described in this article is currently being commercialized under a cooperative agreement between NASA Lewis Research Center and Sonix, Inc.

NEET In-Pile Ultrasonic Sensor Enablement-Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. Daw; J. Rempe; J. Palmer

2014-09-01

Ultrasonic technologies offer the potential to measure a range of parameters during irradiation of fuels and materials, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes under harsh irradiation test conditions. There are two primary issues that currently limit in-pile deployment of ultrasonic sensors. The first is transducer survivability. The ability of ultrasonic transducer materials to maintain their useful properties during an irradiation must be demonstrated. The second issue is signal processing. Ultrasonic testing is typically performed in a lab or field environment, where the sensor and sample are accessible. The harsh nature ofmore » in-pile testing and the variety of desired measurements demand that an enhanced signal processing capability be developed to make in-pile ultrasonic sensors viable. To address these issues, the NEET ASI program funded a three year Ultrasonic Transducer Irradiation and Signal Processing Enhancements project, which is a collaborative effort between the Idaho National Laboratory, the Pacific Northwest National Laboratory, the Argonne National Laboratory, and the Pennsylvania State University. The objective of this report is to document the objectives and accomplishments from this three year project. As summarized within this document, significant work has been accomplished during this three year project.« less

Improved near-field characteristics of phased arrays for assessing concrete and cementitious materials

NASA Astrophysics Data System (ADS)

Wooh, Shi-Chang; Azar, Lawrence

1999-01-01

The degradation of civil infrastructure has placed a focus on effective nondestructive evaluation techniques to correctly assess the condition of existing concrete structures. Conventional high frequency ultrasonic response are severely affected by scattering and material attenuation, resulting in weak and confusing signal returns. Therefore, low frequency ultrasonic transducers, which avoid this problem of wave attenuation, are commonly used for concrete with limited capabilities. The focus of this research is to ascertain some benefits and limitations of a low frequency ultrasonic phased array transducer. In this paper, we investigate a novel low-frequency ultrasonic phased array and the results of experimental feasibility test for practical condition assessment of concrete structures are reported.

Performance of PIN-PMN-PT Single Crystal Piezoelectric versus PZT8 Piezoceramic Materials in Ultrasonic Transducers

NASA Astrophysics Data System (ADS)

DeAngelis, D. A.; Schulze, G. W.

The recent advancements in the manufacturing of single crystal PIN-PMN-PT piezoelectric materials now make them a cost-competitive alternative to PZT4 and PZT8 (Navy Types I and III) piezoceramic materials, which have been the workhorse of power ultrasonic applications (e.g., welding, cutting, sonar, etc.) for over 50 years. Although there are great benefits to the use of single crystal materials with respect to high output, as well as added actuating and sensing abilities, many transducer designers are still reluctant to explore these materials due to inadequate design guidelines for substituting the familiar PZT materials; for example, what are the implications of the higher capacitance, sensitivity to chipping/cracks, aging effects, frequency shifts, or how much preload can be used are all common questions. This research is a case study on the performance of identical ultrasonic transducer bodies, used for semiconductor wire bonding, assembled with either PZT8 or PIN-PMN-PT piezo material. The main purpose of the study is to establish rule-of-thumb design guidelines for direct substitution of single crystal materials in existing PZT8 transducer designs, along with a side-by-side performance comparison to highlight benefits. Several metrics are investigated such as impedance, frequency, displacement gain, quality factor and electromechanical coupling factor.

High Temperature Ultrasonic Transducer for Real-time Inspection

NASA Astrophysics Data System (ADS)

Amini, Mohammad Hossein; Sinclair, Anthony N.; Coyle, Thomas W.

A broadband ultrasonic transducer with a novel porous ceramic backing layer is introduced to operate at 700 °C. 36° Y-cut lithium niobate (LiNbO3) single crystal was selected for the piezoelectric element. By appropriate choice of constituent materials, porosity and pore size, the acoustic impedance and attenuation of a zirconia-based backing layer were optimized. An active brazing alloy with high temperature and chemical stability was selected to bond the transducer layers together. Prototype transducers have been tested at temperatures up to 700 °C. The experiments confirmed that transducer integrity was maintained.

Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection

NASA Technical Reports Server (NTRS)

Huber, Robert D.; Green, Robert E., Jr.; Vary, Alex; Kautz, Harold

1990-01-01

Presented in viewgraph format, the possibility of using laser generation and detection of ultrasound to replace piezoelectric transducers for the acousto-ultrasonic technique is advanced. The advantages and disadvantages of laser acousto-ultrasonics are outlined. Laser acousto-ultrasonics complements standard piezoelectric acousto-ultrasonics and offers non-contact nondestructive evaluation.

Airborne ultrasonic transducer using polymer-based elastomer with high output-to-weight ratio

NASA Astrophysics Data System (ADS)

Wu, Jiang; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

2015-08-01

With the properties of low density, low elastic modulus, and low mechanical loss, poly(phenylene sulfide) (PPS) is a suitable material as the elastomer in an airborne ultrasonic transducer for generating large vibration velocity. In this study, we design and fabricate a transducer composed of a PPS-based longitudinal vibrator and a PPS-based disk of 0.3 mm thickness to obtain high-intensity ultrasound. The rated sound pressure at a distance of 300 mm reached 38.9 Pa (125 dB, 0 dB re. 0.02 mPa) when the frequency and voltage were 58.90 kHz and 20 V. The weight of this transducer is 6.3 g. The ratio of the sound pressure to the weight of the prototype transducer is 1.8 times larger than that of the commercial transducer. The experimental results indicate that PPS is a good substitute for metal as the elastomer for manufacturing airborne ultrasonic transducers with a high output-to-weight ratio.

Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.

PubMed

Saffar, Saber; Abdullah, Amir

2014-03-01

Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. Copyright © 2013 Elsevier B.V. All rights reserved.

System and methods to determine and monitor changes in microstructural properties

DOEpatents

Turner, Joseph A

2014-11-18

A system and methods with which changes in microstructure properties such as grain size, grain elongation, texture, and porosity of materials can be determined and monitored over time to assess conditions such as stress and defects. An example system includes a number of ultrasonic transducers configured to transmit ultrasonic waves towards a target region on a specimen, a voltage source configured to excite the first and second ultrasonic transducers, and a processor configured to determine one or more properties of the specimen.

Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings.

PubMed

Tian, Jiajun; Zhang, Qi; Han, Ming

2013-03-11

Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiber-optic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasi-distributed biochemical fiber-optic sensing.

Cellular polypropylene polymer foam as air-coupled ultrasonic transducer materials.

PubMed

Satyanarayan, L; Haberman, Michael R; Berthelot, Yves H

2010-10-01

Cellular polypropylene polymer foams, also known as ferroelectrets, are compelling candidates for air-coupled ultrasonic transducer materials because of their excellent acoustic impedance match to air and because they have a piezoelectric d(33) coefficient superior to that of PVDF. This study investigates the performance of ferroelectret transducers in the generation and reception of ultrasonic waves in air. As previous studies have noted, the piezoelectric coupling coefficients of these foams depend on the number, size, and distribution of charged voids in the microstructure. The present work studies the influence of these parameters both theoretically and experimentally. First, a three-dimensional model is employed to explain the variation of piezoelectric coupling coefficients, elastic stiffness, and dielectric permittivity as a function of void fraction based on void-scale physics and void geometry. Laser Doppler vibrometer (LDV) measurements of the effective d(33) coefficient of a specially fabricated prototype transmitting transducer are then shown which clearly indicate that the charged voids in the ferroelectret material are randomly distributed in the plane of the foam. The frequency-dependent dynamic d(33) coefficient is then reported from 50 to 500 kHz for different excitation voltages and shown to be largely insensitive to drive voltage. Lastly, two ferroelectret transducers are operated in transmit-receive mode and the received signal is shown to accurately represent the corresponding signal generated by the transmitting transducer as measured using LDV.

Floating Ultrasonic Transducer Inspection System and Method for Nondestructive Evaluation

NASA Technical Reports Server (NTRS)

Johnston, Patrick H. (Inventor); Zalameda, Joseph N. (Inventor)

2016-01-01

A method for inspecting a structural sample using ultrasonic energy includes positioning an ultrasonic transducer adjacent to a surface of the sample, and then transmitting ultrasonic energy into the sample. Force pulses are applied to the transducer concurrently with transmission of the ultrasonic energy. A host machine processes ultrasonic return pulses from an ultrasonic pulser/receiver to quantify attenuation of the ultrasonic energy within the sample. The host machine detects a defect in the sample using the quantified level of attenuation. The method may include positioning a dry couplant between an ultrasonic transducer and the surface. A system includes an actuator, an ultrasonic transducer, a dry couplant between the transducer the sample, a scanning device that moves the actuator and transducer, and a measurement system having a pulsed actuator power supply, an ultrasonic pulser/receiver, and a host machine that executes the above method.

Review of piezoelectric micromachined ultrasonic transducers and their applications

NASA Astrophysics Data System (ADS)

Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Shin, Eunjung; Ryu, Jungho; Choi, Hongsoo

2017-11-01

In recent decades, micromachined ultrasonic transducers (MUTs) have been investigated as an alternative to conventional piezocomposite ultrasonic transducers, primarily due to the advantages that microelectromechanical systems provide. Miniaturized ultrasonic systems require ultrasonic transducers integrated with complementary metal-oxide-semiconductor circuits. Hence, piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs) have been developed as the most favorable solutions. This paper reviews the basic equations to understand the characteristics of thin-film-based piezoelectric devices and presents recent research on pMUTs, including current approaches and limitations. Methods to improve the coupling coefficient of pMUTs are also investigated, such as device structure, materials, and fabrication techniques. The device structure improvements include multielectrode pMUTs, partially clamped boundary conditions, and 3D pMUTs (curved and domed types), where the latter can provide an electromechanical coupling coefficient of up to 45%. The piezoelectric coefficient (e 31) can be increased by controlling the crystal texture (seed layer of γ-Al2O3), using single-crystal (PMN-PT) materials, or control of residual stresses (using SiO2 layer). Arrays of pMUTs can be implemented for various applications including intravascular ultrasound, fingerprint sensors, rangefinders in air, and wireless power supply systems. pMUTs are expected to be an ideal solution for applications such as mobile biometric security (fingerprint sensors) and rangefinders due to their superior power efficiency and compact size.

A Micro Ultrasonic Scalpel with Modified Stepped Horn

NASA Astrophysics Data System (ADS)

Kurosawa, Minoru; Umehara, Yuji

A transducer for a micro ultrasonic scalpel has been fabricated. The micro ultrasonic scalpel can be used with an endoscope for a non-abdominal operation or micro surgery, for example, through a microscope. The ultrasonic transducer was 9.8 mm long and 2.7 mm wide and has stepped horn to amplify vibration velocity; tip of the horn is 0.6 mm wide. The scalpel operated at the resonance frequency in longitudinal mode of 278 kHz. The piezoelectric material was lead zirconate titanate (PZT) that was deposited by the hydrothermal method. The vibration velocity at the tip of the horn in longitudinal direction was 4.0 m/s with 40Vp-p driving voltage in both side electrodes. To demonstrate a beneficial effect of the scalpel, a cutting test that the transducer was stuck into pork fat was carried out.

Damage Assessment of Creep Tested and Thermally Aged Metallic Alloys Using Acousto-Ultrasonics

NASA Technical Reports Server (NTRS)

Gyekenyesi, Andrew L.; Kautz, Harold E.; Baaklini, George Y.

2001-01-01

In recent years emphasis has been placed on the early detection of material changes experienced in turbine powerplant components. During the scheduled overhaul of a turbine, the current techniques of examination of various hot section components aim to find flaws such as cracks, wear, and erosion, as well as excessive deformations. Thus far, these localized damage modes have been detected with satisfactory results. However, the techniques used to find these flaws provide no information on life until the flaws are actually detected. Major improvements in damage assessment, safety, as well as more accurate life prediction could be achieved if nondestructive evaluation (NDE) techniques could be utilized to sense material changes that occur prior to the localized defects mentioned. Because of elevated temperatures and excessive stresses, turbine components may experience creep behavior. As a result, it is desirable to monitor and access the current condition of such components. Research at the NASA Glenn Research Center involves developing and utilizing an NDE technique that discloses distributed material changes that occur prior to the localized damage detected by the current methods of inspection. In a recent study, creep processes in a nickel-base alloy were the life-limiting condition of interest, and the NDE technique was acousto-ultrasonics (AU). AU is an NDE technique that utilizes two ultrasonic transducers to interrogate the condition of a test specimen. The sending transducer introduces an ultrasonic pulse at a point on the surface of the specimen while a receiving transducer detects the signal after it has passed through the material. The goal of the method is to correlate certain parameters of the detected waveform to characteristics of the material between the two transducers. Here, the waveform parameter of interest is the attenuation due to internal damping for which information is being garnered from the frequency domain. The parameters utilized to indirectly quantify the attenuation are the ultrasonic decay rate as well as various moments of the frequency power spectrum. A new, user-friendly, graphical interface AU system was developed at NASA Glenn. This system is an all-inclusive, multifunction system that controls the sending and receiving ultrasonic transducers as well as all posttest signal analysis. The system's postprocessing software calculates the multiple parameters used to study the material of interest.

Ultrasonic pulser-receiver

DOEpatents

Taylor, Steven C.

2006-09-12

Ultrasonic pulser-receiver circuitry, for use with an ultrasonic transducer, the circuitry comprising a circuit board; ultrasonic pulser circuitry supported by the circuit board and configured to be coupled to an ultrasonic transducer and to cause the ultrasonic transducer to emit an ultrasonic output pulse; receiver circuitry supported by the circuit board, coupled to the pulser circuitry, including protection circuitry configured to protect against the ultrasonic pulse and including amplifier circuitry configured to amplify an echo, received back by the transducer, of the output pulse; and a connector configured to couple the ultrasonic transducer directly to the circuit board, to the pulser circuitry and receiver circuitry, wherein impedance mismatches that would result if the transducer was coupled to the circuit board via a cable can be avoided.

Influence of the thickness of multilayer matching systems on the transfer function of ultrasonic airborne transducer.

PubMed

Opieliński, Krzysztof J; Gudra, Tadeusz

2002-05-01

The effective ultrasonic energy radiation into the air of piezoelectric transducers requires using multilayer matching systems with accurately selected acoustic impedances and the thickness of particular layers. This problem is of particular importance in the case of ultrasonic transducers working at a frequency above 1 MHz. Because the possibilities of choosing material with required acoustic impedance are limited (the counted values cannot always be realised and applied in practice) it is necessary to correct the differences between theoretical values and the possibilities of practical application of given acoustic impedances. Such a correction can be done by manipulating other parameters of matching layers (e.g. by changing their thickness). The efficiency of the energy transmission from the piezoceramic transducer through different layers with different thickness enabling a compensation of non-ideal real values by changing their thickness was computer analysed. The result of this analysis is the conclusion that from the technological point of view a layer with defined thickness is easier and faster to produce than elaboration of a new material with required acoustic parameter.

High temperature ultrasonic transducers for the generation of guided waves for non-destructive evaluation of pipes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinding, K.; Searfass, C.; Malarich, N.

2014-02-18

Applications for non-destructive evaluation and structural health monitoring of steam generators require ultrasonic transducers capable of withstanding the high temperatures of the pipes and heat exchangers. These applications require a strong coupling of the transducer to the heat exchanger’s complex geometry at the elevated temperatures. Our objective is to use spray-on piezo-electrics for depositing comb transducers onto the curved surfaces. This paper shows results for composite transducers such as lead zirconate titanate/ bismuth titanate and bismuth titanate/ lithium niobate. The comb transducers were prepared by precision laser ablation. The feasibility of producing second harmonic waves in rods with these spay-onmore » comb transducers was demonstrated and paves the way toward measuring material degradation early-on before crack initiation occurs.« less

Development of Multiple-Frequency Ultrasonic Imaging System Using Multiple Resonance Piezoelectric Transducer

NASA Astrophysics Data System (ADS)

Akiyama, Iwaki; Yoshizumi, Natsuki; Saito, Shigemi; Wada, Yuji; Koyama, Daisuke; Nakamura, Kentaro

2012-07-01

The authors have developed a multiple frequency imaging system using a multiple resonance transducer (MRT) consisting of 1-3 composite materials with a low mechanical quality factor Q bonded together. The MRT has a structure consisting of thin and thick piezoelectric plates, two matching layers, and a backing layer. This makes it possible to obtain B-mode images of satisfactory resolution using ultrasonic pulses owing to their short duration. In this paper, the vibration property of the MRT derived through equivalent-circuit analysis is first shown. By utilizing the result, an MRT capable of transmitting ultrasonic pulses for generation of the images of biological tissues with satisfactory resolution is designed and prototyped. Setting the prototype transducer in the mechanical sector probe of commercial ultrasonic diagnosis equipment, the speckle reduction effect is demonstrated using images of various phantoms to mimic biological tissues and a human thyroid.

Polymer subtrates for dry-coupled ultrasonic transducers

NASA Astrophysics Data System (ADS)

Komsky, Igor N.

2003-07-01

Dry-coupled inspection techniques are very important for applications on components with non-uniform surfaces and for inspections of advanced materials or coatings that are porous or otherwise sensitive to the application of water, gel, or some other ultrasonic couplants. To overcome the problems associated with the liquid coupling medium, a number of polymer films have been developed to transmit the ultrasound through a dry interface. These materials are very flexible so even low pressure loading is sufficient to adapt the films to the irregular inspection surfaces. Several polymer films have been evaluated to develop dry-coupled substrates for transducer modules. The modules will be utilized to detect and characterize fatigue cracks and corrosion spots in the aircraft structures. Ultrasonic properties of the polymer films were measured and compared with the properties of plastic or rubber-like materials commonly used for ultrasonic applications. Experiments have been carried out to analyze propagation of longitudinal and shear waves in the films. Two different types of the ultrasonic modules with the flexible polymer substrates are being developed. The influence of the surface condition on the module performance was evaluated for both types of the modules.

Ultrasonic pipe assessment

DOEpatents

Thomas, Graham H.; Morrow, Valerie L.; Levie, Harold; Kane, Ronald J.; Brown, Albert E.

2003-12-23

An ultrasonic pipe or other structure assessment system includes an ultrasonic transducer positioned proximate the pipe or other structure. A fluid connection between the ultrasonic transducer and the pipe or other structure is produced. The ultrasonic transducer is moved relative to the pipe or other structure.

Encapsulation of Capacitive Micromachined Ultrasonic Transducers Using Viscoelastic Polymer

PubMed Central

Lin, Der-Song; Zhuang, Xuefeng; Wong, Serena H.; Kupnik, Mario; Khuri-Yakub, Butrus Thomas

2010-01-01

The packaging of a medical imaging or therapeutic ultrasound transducer should provide protective insulation while maintaining high performance. For a capacitive micromachined ultrasonic transducer (CMUT), an ideal encapsulation coating would therefore require a limited and predictable change on the static operation point and the dynamic performance, while insulating the high dc and dc actuation voltages from the environment. To fulfill these requirements, viscoelastic materials, such as polydimethylsiloxane (PDMS), were investigated for an encapsulation material. In addition, PDMS, with a glass-transition temperature below room temperature, provides a low Young's modulus that preserves the static behavior; at higher frequencies for ultrasonic operation, this material becomes stiffer and acoustically matches to water. In this paper, we demonstrate the modeling and implementation of the viscoelastic polymer as the encapsulation material. We introduce a finite element model (FEM) that addresses viscoelasticity. This enables us to correctly calculate both the static operation point and the dynamic behavior of the CMUT. CMUTs designed for medical imaging and therapeutic ultrasound were fabricated and encapsulated. Static and dynamic measurements were used to verify the FEM and show excellent agreement. This paper will help in the design process for optimizing the static and the dynamic behavior of viscoelastic-polymer-coated CMUTs. PMID:21170294

Metal composite as backing for ultrasonic transducers dedicated to non-destructive measurements in hostile

NASA Astrophysics Data System (ADS)

Boubenia, R.; Rosenkrantz, E.; Despetis, F.; P, P.; Ferrandis, J.-Y.

2016-03-01

Our team is specialized in ultrasonic measurements in hostile environment especially under high temperatures. There is a need for acoustic transducers capable of continuous measurement at temperatures up to 700°C. To improve the performances of acoustic sensors we focus our works on the realisation and characterisation of transducer backings able to operate under very high temperature. Commercially, they are produced by the incorporation of tungsten powder in a plastic matrix, which limits the working temperature. The realisation of ultrasonic transducers for non-destructive measures at high temperatures requires adequate materials, manufacturing and assembly processes. To produce the backings, composites were made using very ductile metals such as tin and tungsten. These composites are manufactured by uniaxial hot pressing. First, we studied the influence of temperature and pressure on the densification of tin pellets. Then, several specimens made of tin/W were made and characterised by measuring the specific weight, speed and attenuation of sound. The acoustic measures were realised by ultrasonic spectroscopy. This test-bench was designed and tested on control samples of PMMA and on standard backings (epoxy / tungsten).

Ultrasonic detection technology based on joint robot on composite component with complex surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Juan; Xu, Chunguang; Zhang, Lan

Some components have complex surface, such as the airplane wing and the shell of a pressure vessel etc. The quality of these components determines the reliability and safety of related equipment. Ultrasonic nondestructive detection is one of the main methods used for testing material defects at present. In order to improve the testing precision, the acoustic axis of the ultrasonic transducer should be consistent with the normal direction of the measured points. When we use joint robots, automatic ultrasonic scan along the component surface normal direction can be realized by motion trajectory planning and coordinate transformation etc. In order tomore » express the defects accurately and truly, the robot position and the signal of the ultrasonic transducer should be synchronized.« less

Apparatus for disintegrating kidney stones

NASA Technical Reports Server (NTRS)

Angulo, E. D. (Inventor)

1984-01-01

The useful life of the wire probe in an ultrasonic kidney stone disintegration instrument is enhanced and prolonged by attaching the wire of the wire probe to the tip of an ultrasonic transducer by means of a clamping arrangement. Additionally, damping material is applied to the wire probe in the form of a damper tube through which the wire probe passes in the region adjacent the transducer tip. The damper tube extends outwardly from the transducer tip a predetermined distance, terminating in a resilient soft rubber joint. Also, the damper tube is supported intermediate its length by a support member. The damper system thus acts to inhibit lateral vibrations of the wire in the region of the transducer tip while providing little or no damping to the linear vibrations imparted to the wire by the transducer.

Apparatus for monitoring high temperature ultrasonic characterization

DOEpatents

Lanagan, Michael T.; Kupperman, David S.; Yaconi, George A.

1998-01-01

A method and an apparatus for nondestructive detecting and evaluating chas in the microstructural properties of a material by employing one or more magnetostrictive transducers linked to the material by means of one or more sonic signal conductors. The magnetostrictive transducer or transducers are connected to a pulser/receiver which in turn is connected to an oscilloscope. The oscilloscope is connected to a computer which employs an algorithm to evaluate changes in the velocity of a signal transmitted to the material sample as function of time and temperature.

Phononic Crystal Waveguide Transducers for Nonlinear Elastic Wave Sensing.

PubMed

Ciampa, Francesco; Mankar, Akash; Marini, Andrea

2017-11-07

Second harmonic generation is one of the most sensitive and reliable nonlinear elastic signatures for micro-damage assessment. However, its detection requires powerful amplification systems generating fictitious harmonics that are difficult to discern from pure nonlinear elastic effects. Current state-of-the-art nonlinear ultrasonic methods still involve impractical solutions such as cumbersome signal calibration processes and substantial modifications of the test component in order to create material-based tunable harmonic filters. Here we propose and demonstrate a valid and sensible alternative strategy involving the development of an ultrasonic phononic crystal waveguide transducer that exhibits both single and multiple frequency stop-bands filtering out fictitious second harmonic frequencies. Remarkably, such a sensing device can be easily fabricated and integrated on the surface of the test structure without altering its mechanical and geometrical properties. The design of the phononic crystal structure is supported by a perturbative theoretical model predicting the frequency band-gaps of periodic plates with sinusoidal corrugation. We find our theoretical findings in excellent agreement with experimental testing revealing that the proposed phononic crystal waveguide transducer successfully attenuates second harmonics caused by the ultrasonic equipment, thus demonstrating its wide range of potential applications for acousto/ultrasonic material damage inspection.

Simple model for piezoelectric ceramic/polymer 1-3 composites used in ultrasonic transducer applications.

PubMed

Chan, H W; Unsworth, J

1989-01-01

A theoretical model is presented for combining parameters of 1-3 ultrasonic composite materials in order to predict ultrasonic characteristics such as velocity, acoustic impedance, electromechanical coupling factor, and piezoelectric coefficients. Hence, the model allows the estimation of resonance frequencies of 1-3 composite transducers. This model has been extended to cover more material parameters, and they are compared to experimental results up to PZT volume fraction nu of 0.8. The model covers calculation of piezoelectric charge constants d(33) and d(31). Values are found to be in good agreement with experimental results obtained for PZT 7A/Araldite D 1-3 composites. The acoustic velocity, acoustic impedance, and electromechanical coupling factor are predicted and found to be close to the values determined experimentally.

Low-cost ultrasonic lamb-wave transducer

NASA Technical Reports Server (NTRS)

Kammerer, C. C.

1978-01-01

Transducer propagates Lamb wave through thin aluminum sheet material. Model includes two elements that measure effects of damping and loading which, in turn, are indirectly equated to bond integrity. Transducer has been used to evaluate bond integrity of aluminum facing adhesively bonded to aluminum facing. Because of versatility, it is now possible to inspect many objects of different configurations that could not be reached with earlier transducers.

Auto-positioning ultrasonic transducer system

NASA Technical Reports Server (NTRS)

Buchanan, Randy K. (Inventor)

2010-01-01

An ultrasonic transducer apparatus and process for determining the optimal transducer position for flow measurement along a conduit outer surface. The apparatus includes a transmitting transducer for transmitting an ultrasonic signal, said transducer affixed to a conduit outer surface; a guide rail attached to a receiving transducer for guiding movement of a receiving transducer along the conduit outer surface, wherein the receiving transducer receives an ultrasonic signal from the transmitting transducer and sends a signal to a data acquisition system; and a motor for moving the receiving transducer along the guide rail, wherein the motor is controlled by a controller. The method includes affixing a transmitting transducer to an outer surface of a conduit; moving a receiving transducer on the conduit outer surface, wherein the receiving transducer is moved along a guide rail by a motor; transmitting an ultrasonic signal from the transmitting transducer that is received by the receiving transducer; communicating the signal received by the receiving transducer to a data acquisition and control system; and repeating the moving, transmitting, and communicating along a length of the conduit.

Piezoelectric films for high frequency ultrasonic transducers in biomedical applications

PubMed Central

Zhou, Qifa; Lau, Sienting; Wu, Dawei; Shung, K. Kirk

2011-01-01

Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the current status of the piezoelectric films and recent progress in the development of high frequency ultrasonic transducers will be discussed. Then details for preparation and structure of the materials derived from piezoelectric thick film technologies will be described. Both chemical and physical methods are included in the discussion, namely, the sol–gel approach, aerosol technology and hydrothermal method. The electric and piezoelectric properties of the piezoelectric films, which are very important for transducer applications, such as permittivity and electromechanical coupling factor, are also addressed. Finally, the recent developments in the high frequency transducers and arrays with piezoelectric ZnO and PZT thick film using MEMS technology are presented. In addition, current problems and further direction of the piezoelectric films for very high frequency ultrasound application (up to GHz) are also discussed. PMID:21720451

Piezoelectric films for high frequency ultrasonic transducers in biomedical applications.

PubMed

Zhou, Qifa; Lau, Sienting; Wu, Dawei; Shung, K Kirk

2011-02-01

Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the current status of the piezoelectric films and recent progress in the development of high frequency ultrasonic transducers will be discussed. Then details for preparation and structure of the materials derived from piezoelectric thick film technologies will be described. Both chemical and physical methods are included in the discussion, namely, the sol-gel approach, aerosol technology and hydrothermal method. The electric and piezoelectric properties of the piezoelectric films, which are very important for transducer applications, such as permittivity and electromechanical coupling factor, are also addressed. Finally, the recent developments in the high frequency transducers and arrays with piezoelectric ZnO and PZT thick film using MEMS technology are presented. In addition, current problems and further direction of the piezoelectric films for very high frequency ultrasound application (up to GHz) are also discussed.

Embedded Ultrasonic Transducers for Active and Passive Concrete Monitoring

PubMed Central

Niederleithinger, Ernst; Wolf, Julia; Mielentz, Frank; Wiggenhauser, Herbert; Pirskawetz, Stephan

2015-01-01

Recently developed new transducers for ultrasonic transmission, which can be embedded right into concrete, are now used for non-destructive permanent monitoring of concrete. They can be installed during construction or thereafter. Large volumes of concrete can be monitored for changes of material properties by a limited number of transducers. The transducer design, the main properties as well as installation procedures are presented. It is shown that compressional waves with a central frequency of 62 kHz are mainly generated around the transducer’s axis. The transducer can be used as a transmitter or receiver. Application examples demonstrate that the transducers can be used to monitor concrete conditions parameters (stress, temperature, …) as well as damages in an early state or the detection of acoustic events (e.g., crack opening). Besides application in civil engineering our setups can also be used for model studies in geosciences. PMID:25923928

Ultrasonic measurements of surface defects on flexible circuits using high-frequency focused polymer transducers

NASA Astrophysics Data System (ADS)

Wagle, Sanat; Habib, Anowarul; Melandsø, Frank

2017-07-01

High-frequency transducers made from a layer-by-layer deposition method are investigated as transducers for ultrasonic imaging. Prototypes of adhesive-free transducers with four active elements were made on a high-performance poly(ether imide) substrate with precision milled spherical cavities used to produce focused ultrasonic beams. The transducer prototypes were characterized using a pulse-echo experimental setup in a water tank using a glass plate as a reflector. Then, transducer was used in a three-dimensional ultrasonic scanning tank, to produce high-resolution ultrasonic images of flexible electronic circuits with the aim to detect defects in the outermost cover layer.

Electronic system for floor surface type detection in robotics applications

NASA Astrophysics Data System (ADS)

Tarapata, Grzegorz; Paczesny, Daniel; Tarasiuk, Łukasz

2016-11-01

The paper reports a recognizing method base on ultrasonic transducers utilized for the surface types detection. Ultra-sonic signal is transmitted toward the examined substrate, then reflected and scattered signal goes back to another ultra-sonic receiver. Thee measuring signal is generated by a piezo-electric transducer located at specified distance from the tested substrate. The detector is a second piezo-electric transducer located next to the transmitter. Depending on thee type of substrate which is exposed by an ultrasonic wave, the signal is partially absorbed inn the material, diffused and reflected towards the receiver. To measure the level of received signal, the dedicated electronic circuit was design and implemented in the presented systems. Such system was designed too recognize two types of floor surface: solid (like concrete, ceramic stiles, wood) and soft (carpets, floor coverings). The method will be applied in electronic detection system dedicated to autonomous cleaning robots due to selection of appropriate cleaning method. This work presents the concept of ultrasonic signals utilization, the design of both the measurement system and the measuring stand and as well number of wide tests results which validates correctness of applied ultrasonic method.

High Temperature Ultrasonic Transducers : Material Selection and Testing

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Bruno, Alessandro

2012-01-01

The task of my two-months internship was to test different materials to be used to build an high temperature transducer, to develop some prototypes and to test their performance, to assess the reliability of commercial product rated for such a temperature, as well as to collaborate in developing the signal processing code to measure the condensed water levels.

Bonded ultrasonic transducer and method for making

DOEpatents

Dixon, Raymond D.; Roe, Lawrence H.; Migliori, Albert

1995-01-01

An ultrasonic transducer is formed as a diffusion bonded assembly of piezoelectric crystal, backing material, and, optionally, a ceramic wear surface. The mating surfaces of each component are silver films that are diffusion bonded together under the application of pressure and heat. Each mating surface may also be coated with a reactive metal, such as hafnium, to increase the adhesion of the silver films to the component surfaces. Only thin silver films are deposited, e.g., a thickness of about 0.00635 mm, to form a substantially non-compliant bond between surfaces. The resulting transducer assembly is substantially free of self-resonances over normal operating ranges for taking resonant ultrasound measurements.

Development of lead-free single-element ultrahigh frequency (170 – 320 MHz) ultrasonic transducers

PubMed Central

Lam, Kwok Ho; Ji, Hong Fen; Zheng, Fan; Ren, Wei; Zhou, Qifa; Shung, K. Kirk

2013-01-01

This paper presents the design, fabrication and characterization of single-element ultrahigh frequency (UHF) ultrasonic transducers in which the center frequency ranged from 170 to 320 MHz. The center frequency of > 300 MHz is the highest value of lead-free ceramic ultrasonic transducers ever reported. With concern in the environmental pollution of lead-based materials, the transducer elements presented in this work were lead-free K0.5Na0.5NbO3/Bi0.5Na0.5TiO3 (KNN/BNT) composite thick films. All transducers were evaluated in a pulse-echo arrangement. The measured −6 dB bandwidth of the transducers ranged from 35 to 64 %. With the optimized piezoelectric properties of the composite film, the insertion loss of the UHF transducers was measured and determined to range from −50 to −60 dB. In addition to the pulse-echo measurement, a 6-μm tungsten wire phantom was also imaged with a 205 MHz transducer to demonstrate the imaging capability. The measured −6 dB axial and lateral resolutions were found to be 12 μm and 50 μm, respectively. The transducer performance presented in this work is shown to be better or comparable to previously reported results even though the frequency is much higher. PMID:23485349

Design and some practical applications of ultrasonic transducers with axicon lenses

NASA Astrophysics Data System (ADS)

Katchadjian, P.; Desimone, C.; Garcia, A.

2013-01-01

In this paper the applications, detailed in previous papers, referred to ultrasonic transducers with the addition of axicon lenses are extended. Axicon lenses, both contact and immersion, for normal and angular incidence were manufactured, in order to study defectology in welds and other components. For immersion transducers, as had already been made for contact transducers, signal amplitude in function of the depth of the reflector and transverse acoustic pressure at the focus were measured. For this purpose a small metallic sphere submerged in different fluids was used. Several practical applications are shown where it is possible to exploit the advantages that these transducers offer: high resolution measurements for corrosion, laminations and thickness reduction. Discrimination between a weld root and a defect very close to it, etc. Measurements in anisotropic materials (composites) in order to achieve an SNR improvement.

Absolute calibration technique for broadband ultrasonic transducers

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Cantrell, John H. (Inventor)

1994-01-01

Calibrating an ultrasonic transducer can be performed with a reduced number of calculations and testing. A wide-band pulser is connected to an ultrasonic transducer under test to generate ultrasonic waves in a liquid. A single frequency is transmitted to the electrostatic acoustic transducer (ESAT) and the voltage change produced is monitored. Then a broadband ultrasonic pulse is generated by the ultrasonic transducer and received by the ESAT. The output of the ESAT is amplified and input to a digitized oscilloscope for fast Fourier transform. The resulting plot is normalized with the monitored signal from the single frequency pulse. The plot is then corrected for characteristics of the membrane and diffraction effects. The transfer function of the final plot is determined. The transfer function gives the final sensitivity of the ultrasonic transducer as a function of frequency. The advantage of the system is the speed of calibrating the transducer by a reduced number of measurements and removal of the membrane and diffraction effects.

The Dynamic Performance of Flexural Ultrasonic Transducers.

PubMed

Feeney, Andrew; Kang, Lei; Rowlands, George; Dixon, Steve

2018-01-18

Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems.

The Dynamic Performance of Flexural Ultrasonic Transducers

PubMed Central

Kang, Lei; Rowlands, George; Dixon, Steve

2018-01-01

Flexural ultrasonic transducers are principally used as proximity sensors and for industrial metrology. Their operation relies on a piezoelectric ceramic to generate a flexing of a metallic membrane, which delivers the ultrasound signal. The performance of flexural ultrasonic transducers has been largely limited to excitation through a short voltage burst signal at a designated mechanical resonance frequency. However, a steady-state amplitude response is not generated instantaneously in a flexural ultrasonic transducer from a drive excitation signal, and differences in the drive characteristics between transmitting and receiving transducers can affect the measured response. This research investigates the dynamic performance of flexural ultrasonic transducers using acoustic microphone measurements and laser Doppler vibrometry, supported by a detailed mechanical analog model, in a process which has not before been applied to the flexural ultrasonic transducer. These techniques are employed to gain insights into the physics of their vibration behaviour, vital for the optimisation of industrial ultrasound systems. PMID:29346297

Development of a High Performance Acousto-ultrasonic Scan System

NASA Technical Reports Server (NTRS)

Roth, D. J.; Martin, R. E.; Harmon, L. M.; Gyekenyesi, A. L.; Kautz, H. E.

2002-01-01

Acousto-ultrasonic (AU) interrogation is a single-sided nondestructive evaluation (NDE) technique employing separated sending and receiving transducers. It is used for assessing the microstructural condition/distributed damage state of the material between the transducers. AU is complementary to more traditional NDE methods such as ultrasonic c-scan, x-ray radiography, and thermographic inspection that tend to be used primarily for discrete flaw detection. Through its history, AU has been used to inspect polymer matrix composite, metal matrix composite, ceramic matrix composite, and even monolithic metallic materials. The development of a high-performance automated AU scan system for characterizing within-sample microstructural and property homogeneity is currently in a prototype stage at NASA. In this paper, a review of essential AU technology is given. Additionally, the basic hardware and software configuration, and preliminary results with the system, are described.

Low-frequency ultrasonic Bessel-like collimated beam generation from radial modes of piezoelectric transducers

DOE PAGES

Chillara, Vamshi Krishna; Pantea, Cristian; Sinha, Dipen N.

2017-02-06

We present a very simple approach to generate a collimated ultrasonic beam that exploits the natural Bessel-like vibration pattern of the radial modes of a piezoelectric disc with lateral clamping. This eliminates the need for the conventional annular Bessel pattern of the electrodes with individual electrode excitation on the piezo-disc, thus simplifying the transducer design. Numerical and experimental studies are carried out to investigate the Bessel-like vibration patterns of these radial modes showing an excellent agreement between these two studies. Measured ultrasonic beam- pro les in water from the radial modes con rm the profile to be a Bessel beam.more » Collimated beam generation from radial modes is investigated using a coupled electromechanical finite-element model. It is found that clamping the lateral edges of piezoelectric transducers results in a high-degree of collimation with practically no side-lobes similar to a parametric array beam. Ultrasonic beam- profile measurements in water with both free and clamped piezoelectric transducer are presented. The collimated beam generation using the present technique of using the laterally clamped radial modes finds significant applications in low-frequency imaging through highly attenuating materials.« less

Low-frequency ultrasonic Bessel-like collimated beam generation from radial modes of piezoelectric transducers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chillara, Vamshi Krishna; Pantea, Cristian; Sinha, Dipen N.

We present a very simple approach to generate a collimated ultrasonic beam that exploits the natural Bessel-like vibration pattern of the radial modes of a piezoelectric disc with lateral clamping. This eliminates the need for the conventional annular Bessel pattern of the electrodes with individual electrode excitation on the piezo-disc, thus simplifying the transducer design. Numerical and experimental studies are carried out to investigate the Bessel-like vibration patterns of these radial modes showing an excellent agreement between these two studies. Measured ultrasonic beam- pro les in water from the radial modes con rm the profile to be a Bessel beam.more » Collimated beam generation from radial modes is investigated using a coupled electromechanical finite-element model. It is found that clamping the lateral edges of piezoelectric transducers results in a high-degree of collimation with practically no side-lobes similar to a parametric array beam. Ultrasonic beam- profile measurements in water with both free and clamped piezoelectric transducer are presented. The collimated beam generation using the present technique of using the laterally clamped radial modes finds significant applications in low-frequency imaging through highly attenuating materials.« less

Apparatus for monitoring high temperature ultrasonic characterization

DOEpatents

Lanagan, M.T.; Kupperman, D.S.; Yaconi, G.A.

1998-03-24

A method and an apparatus for nondestructive detecting and evaluating changes in the microstructural properties of a material by employing one or more magnetostrictive transducers linked to the material by means of one or more sonic signal conductors. The magnetostrictive transducer or transducers are connected to a pulser/receiver which in turn is connected to an oscilloscope. The oscilloscope is connected to a computer which employs an algorithm to evaluate changes in the velocity of a signal transmitted to the material sample as function of time and temperature. 6 figs.

Single-Transducer, Ultrasonic Imaging Method for High-Temperature Structural Materials Eliminates the Effect of Thickness Variation in the Image

NASA Technical Reports Server (NTRS)

Roth, Don J.

1998-01-01

NASA Lewis Research Center's Life Prediction Branch, in partnership with Sonix, Inc., and Cleveland State University, recently advanced the development of, refined, and commercialized an advanced nondestructive evaluation (NDE) inspection method entitled the Single Transducer Thickness-Independent Ultrasonic Imaging Method. Selected by R&D Magazine as one of the 100 most technologically significant new products of 1996, the method uses a single transducer to eliminate the superimposing effects of thickness variation in the ultrasonic images of materials. As a result, any variation seen in the image is due solely to microstructural variation. This nondestructive method precisely and accurately characterizes material gradients (pore fraction, density, or chemical) that affect the uniformity of a material's physical performance (mechanical, thermal, or electrical). Advantages of the method over conventional ultrasonic imaging include (1) elimination of machining costs (for precision thickness control) during the quality control stages of material processing and development and (2) elimination of labor costs and subjectivity involved in further image processing and image interpretation. At NASA Lewis, the method has been used primarily for accurate inspections of high temperature structural materials including monolithic ceramics, metal matrix composites, and polymer matrix composites. Data were published this year for platelike samples, and current research is focusing on applying the method to tubular components. The initial publicity regarding the development of the method generated 150 requests for further information from a wide variety of institutions and individuals including the Federal Bureau of Investigation (FBI), Lockheed Martin Corporation, Rockwell International, Hewlett Packard Company, and Procter & Gamble Company. In addition, NASA has been solicited by the 3M Company and Allison Abrasives to use this method to inspect composite materials that are manufactured by these companies.

Broadband focusing ultrasonic transducers based on dimpled LiNbO3 plate with inversion layer.

PubMed

Chen, Jin; Dai, Ji-Yan; Zhang, Chao; Zhang, Zhitian; Feng, Guanping

2012-12-01

A high-frequency broadband focusing transducer based on dimpled LiNbO(3) inversion layer plate has been fabricated and characterized. A spherical surface with a curvature radius of 6 mm is formed on the half-thickness LiNbO(3) inversion layer plate of Y36° cut orientation. The domain structure in the cross section is observed after a hydrofluoric acid etching process. For transducer fabrication, conductive epoxy is used as the backing material and polymer is deposited on the front face as the matching layer. The center frequency, bandwidth, and insertion loss of the focused transducer are measured to be 72 MHz, 136%, and -32 dB, respectively. The focused transducer has been successfully used for rabbit eyeball imaging and a better imaging capability compared with the planar transducer has been demonstrated. These promising results prove that the dimpled LiNbO(3) inversion layer plate has great potential for fabrication of high-frequency broadband focusing ultrasonic transducers.

Nondestructive testing of railroad wheels and rails by ultrasonics

NASA Technical Reports Server (NTRS)

Clotfelter, W. M.; Risch, E. R.

1974-01-01

Quality control of wheels and rails can be improved by using ultrasonic technique developed for measuring stresses in metallic materials. In addition, parts already in use can be tested and replaced if they are found to be unsafe. Test equipment includes two transducers.

Ultrasonic fluid densitometry and densitometer

DOEpatents

Greenwood, Margaret S.; Lail, Jason C.

1998-01-01

The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface.

Ultrasonic fluid densitometry and densitometer

DOEpatents

Greenwood, M.S.; Lail, J.C.

1998-01-13

The present invention is an ultrasonic fluid densitometer that uses a material wedge having an acoustic impedance that is near the acoustic impedance of the fluid, specifically less than a factor of 11 greater than the acoustic impedance of the fluid. The invention also includes a wedge having at least two transducers for transmitting and receiving ultrasonic signals internally reflected within the material wedge. Density of a fluid is determined by immersing the wedge into the fluid and measuring reflection of ultrasound at the wedge-fluid interface. 6 figs.

Longitudinal wave propagation in multi cylindrical viscoelastic matching layers of airborne ultrasonic transducer: new method to consider the matching layer's diameter (frequency <100 kHz).

PubMed

Saffar, Saber; Abdullah, Amir

2013-08-01

Wave propagation in viscoelastic disk layers is encountered in many applications including studies of airborne ultrasonic transducers. For viscoelastic materials, both material and geometric dispersion are possible when the diameter of the matching layer is of the same order as the wavelength. Lateral motions of the matching layer(s) that result from the Poisson effect are accounted by using a new concept called the "effective-density". A new wave equation is derived for both metallic and non-metallic (polymeric) materials, usually employed for the matching layers of airborne ultrasonic transducer. The material properties are modeled by using the Kelvin model for metals and Linear Solid Standard model for non-metallic (polymeric) matching layers. The utilized model of the material of the matching layers has influence on amount and trend of variation in speed ratio. In this regard, 60% reduction in speed ratio is observed for Kelvin model for aluminum with diameter of 80 mm at 100 kHz while for a similar diameter but Standard Linear Model, the speed ratio increase to twice value at 15 kHz, and then reduced until 70% at 67 kHz for Polypropylene. The new wave theory simplifies to the one-dimensional solution for waves in metallic or polymeric matching layers if the Poisson ratio is set to zero. The predictions simplify to Love's equation for stress waves in elastic disks when loss term is removed from equations for both models. Afterwards, the new wave theory is employed to determine the airborne ultrasonic matching layers to maximize the energy transmission to the air. The optimal matching layers are determined by using genetic algorithm theory for 1, 2 and 3 airborne matching layers. It has been shown that 1-D equation is useless at frequencies less than 100 kHz and the effect of diameter of the matching layers must be considered to determine the acoustic impedances (matching layers) to design airborne ultrasonic transducers. Copyright © 2013 Elsevier B.V. All rights reserved.

Non-destructive evaluation means and method of flaw reconstruction utilizing an ultrasonic multi-viewing transducer data acquistion system

DOEpatents

Thompson, Donald O.; Wormley, Samuel J.

1989-03-28

A multi-viewing ultrasound transducer acquisition system for non-destructive evaluation, flaw detection and flaw reconstruction in materials. A multiple transducer assembly includes a central transducer surrounded by a plurality of perimeter transducers, each perimeter transducer having an axis of transmission which can be angularly oriented with respect to the axis of transmission of the central transducer to intersect the axis of transmission of the central transducer. A control apparatus automatically and remotely positions the transducer assembly with respect to the material by a positioning apparatus and adjusts the pe GRANT REFERENCE This invention was conceived and reduced to practice at least in part under a grant from the Department of Energy under Contract No. W-7407-ENG-82.

Airborne ultrasonic inspection in carbon/carbon composite materials

NASA Astrophysics Data System (ADS)

Yang, In-Young; Kim, Young-Hun; Park, Je-Woong; Hsu, David K.; Song, Song-Jin; Cho, Hyun-Jun; Kim, Sun-Kyu; Im, Kwang-Hee

2007-07-01

In this work, a carbon/carbon (C/C) composite material was nondestructively characterized with non-contact ultrasonic methods using automated acquisition scanner as well as contact ultrasonic measurement because (C/C) composite materials have obvious high price over conventional materials. Because of permeation of coupling medium such as water, it is desirable to perform contact-less nondestructive evaluation to assess material properties and part homogeneity. Also through transmission mode was performed because of the main limitation for air-coupled transducers, which is the acoustic impedance mismatch between most materials and air. Especially ultrasonic images and velocities for C/C composite disk brake was measured and found to be consistent to some degree with the non-contact and contact ultrasonic measurement methods. Low frequency through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. Measured results were compared with those obtained by the motorized system with using dry-coupling ultrasonics and through transmission method in immersion. Finally, results using a proposed peak-delay measurement method well corresponded to ultrasonic velocities of the pulse overlap method.

High-Performance Acousto-Ultrasonic Scan System Being Developed

NASA Technical Reports Server (NTRS)

Roth, Don J.; Martin, Richard E.; Cosgriff, Laura M.; Gyekenyesi, Andrew L.; Kautz, Harold E.

2003-01-01

Acousto-ultrasonic (AU) interrogation is a single-sided nondestructive evaluation (NDE) technique employing separated sending and receiving transducers. It is used for assessing the microstructural condition and distributed damage state of the material between the transducers. AU is complementary to more traditional NDE methods, such as ultrasonic cscan, x-ray radiography, and thermographic inspection, which tend to be used primarily for discrete flaw detection. Throughout its history, AU has been used to inspect polymer matrix composites, metal matrix composites, ceramic matrix composites, and even monolithic metallic materials. The development of a high-performance automated AU scan system for characterizing within-sample microstructural and property homogeneity is currently in a prototype stage at NASA. This year, essential AU technology was reviewed. In addition, the basic hardware and software configuration for the scanner was developed, and preliminary results with the system were described. Mechanical and environmental loads applied to composite materials can cause distributed damage (as well as discrete defects) that plays a significant role in the degradation of physical properties. Such damage includes fiber/matrix debonding (interface failure), matrix microcracking, and fiber fracture and buckling. Investigations at the NASA Glenn Research Center have shown that traditional NDE scan inspection methods such as ultrasonic c-scan, x-ray imaging, and thermographic imaging tend to be more suited to discrete defect detection rather than the characterization of accumulated distributed micro-damage in composites. Since AU is focused on assessing the distributed micro-damage state of the material in between the sending and receiving transducers, it has proven to be quite suitable for assessing the relative composite material state. One major success story at Glenn with AU measurements has been the correlation between the ultrasonic decay rate obtained during AU inspection and the mechanical modulus (stiffness) seen during fatigue experiments with silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite samples. As shown in the figure, ultrasonic decay increased as the modulus decreased for the ceramic matrix composite tensile fatigue samples. The likely microstructural reason for the decrease in modulus (and increase in ultrasonic decay) is the matrix microcracking that commonly occurs during fatigue testing of these materials. Ultrasonic decay has shown the capability to track the pattern of transverse cracking and fiber breakage in these composites.

High-Performance Acousto-Ultrasonic Scan System Being Developed

NASA Technical Reports Server (NTRS)

Roth, Don J.; Martin, Richard E.; Cosgriff, Laura M.; Gyekenyesi, Andrew L.; Kautz, Harold E.

2003-01-01

Acousto-ultrasonic (AU) interrogation is a single-sided nondestructive evaluation (NDE) technique employing separated sending and receiving transducers. It is used for assessing the microstructural condition and distributed damage state of the material between the transducers. AU is complementary to more traditional NDE methods, such as ultrasonic cscan, x-ray radiography, and thermographic inspection, which tend to be used primarily for discrete flaw detection. Throughout its history, AU has been used to inspect polymer matrix composites, metal matrix composites, ceramic matrix composites, and even monolithic metallic materials. The development of a high-performance automated AU scan system for characterizing within-sample microstructural and property homogeneity is currently in a prototype stage at NASA. This year, essential AU technology was reviewed. In addition, the basic hardware and software configuration for the scanner was developed, and preliminary results with the system were described. Mechanical and environmental loads applied to composite materials can cause distributed damage (as well as discrete defects) that plays a significant role in the degradation of physical properties. Such damage includes fiber/matrix debonding (interface failure), matrix microcracking, and fiber fracture and buckling. Investigations at the NASA Glenn Research Center have shown that traditional NDE scan inspection methods such as ultrasonic c-scan, x-ray imaging, and thermographic imaging tend to be more suited to discrete defect detection rather than the characterization of accumulated distributed microdamage in composites. Since AU is focused on assessing the distributed microdamage state of the material in between the sending and receiving transducers, it has proven to be quite suitable for assessing the relative composite material state. One major success story at Glenn with AU measurements has been the correlation between the ultrasonic decay rate obtained during AU inspection and the mechanical modulus (stiffness) seen during fatigue experiments with silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite samples. As shown in the figure, ultrasonic decay increased as the modulus decreased for the ceramic matrix composite tensile fatigue samples. The likely microstructural reason for the decrease in modulus (and increase in ultrasonic decay) is the matrix microcracking that commonly occurs during fatigue testing of these materials. Ultrasonic decay has shown the capability to track the pattern of transverse cracking and fiber breakage in these composites.

80-MHz intravascular ultrasound transducer using PMN-PT free-standing film.

PubMed

Li, Xiang; Wu, Wei; Chung, Youngsoo; Shih, Wan Y; Shih, Wei-Heng; Zhou, Qifa; Shung, K Kirk

2011-11-01

[Pb(Mg(1/3)Nb(2/3))O(3)](0.63)[PbTiO(3)](0.37) (PMN-PT) free-standing film of comparable piezoelectric properties to bulk material with thickness of 30 μm has been fabricated using a modified precursor coating approach. At 1 kHz, the dielectric permittivity and loss were 4364 and 0.033, respectively. The remnant polarization and coercive field were 28 μC/cm(2) and 18.43 kV/cm. The electromechanical coupling coefficient k(t) was measured to be 0.55, which was close to that of bulk PMN-PT single-crystal material. Based on this film, high-frequency (82 MHz) miniature ultrasonic transducers were fabricated with 65% bandwidth and 23 dB insertion loss. Axial and lateral resolutions were determined to be as high as 35 and 176 μm. In vitro intravascular imaging on healthy rabbit aorta was performed using the thin film transducers. In comparison with a 35-MHz IVUS transducer, the 80-MHz transducer showed superior resolution and contrast with satisfactory penetration depth. The imaging results suggest that PMN-PT free-standing thin film technology is a feasible and efficient way to fabricate very-high-frequency ultrasonic transducers.

Bonded ultrasonic transducer and method for making

DOEpatents

Dixon, R.D.; Roe, L.H.; Migliori, A.

1995-11-14

An ultrasonic transducer is formed as a diffusion bonded assembly of piezoelectric crystal, backing material, and, optionally, a ceramic wear surface. The mating surfaces of each component are silver films that are diffusion bonded together under the application of pressure and heat. Each mating surface may also be coated with a reactive metal, such as hafnium, to increase the adhesion of the silver films to the component surfaces. Only thin silver films are deposited, e.g., a thickness of about 0.00635 mm, to form a substantially non-compliant bond between surfaces. The resulting transducer assembly is substantially free of self-resonances over normal operating ranges for taking resonant ultrasound measurements. 12 figs.

A New High-Temperature Ultrasonic Transducer for Continuous Inspection.

PubMed

Amini, Mohammad Hossein; Sinclair, Anthony N; Coyle, Thomas W

2016-03-01

A novel design of piezoelectric ultrasonic transducer is introduced, suitable for operation at temperatures of up to 700 °C-800 °C. Lithium niobate single crystal is chosen as the piezoelectric element primarily due to the high Curie temperature of 1200 °C. A backing element based on a porous ceramic is designed for which the pore volume fraction and average pore diameter in the ceramic matrix can be controlled in the manufacturing process; this enables the acoustic impedance and attenuation to be selected to match their optimal values as predicted by a one-dimensional transducer model of the entire transducer. Porous zirconia is selected as the ceramic matrix material of the backing element to obtain an ultrasonic signal with center frequency of 2.7-3 MHz, and 3-dB bandwidth of 90%-95% at the targeted operating temperature. Acoustic coupling of the piezocrystal to the backing element and matching layer is investigated using commercially available high-temperature adhesives and brazing alloys. The performance of the transducer as a function of temperature is studied. Stable bonding and clear signals were obtained using an aluminum brazing alloy as the bonding agent.

Advanced Bode Plot Techniques for Ultrasonic Transducers

NASA Astrophysics Data System (ADS)

DeAngelis, D. A.; Schulze, G. W.

The Bode plot, displayed as either impedance or admittance versus frequency, is the most basic test used by ultrasonic transducer designers. With simplicity and ease-of-use, Bode plots are ideal for baseline comparisons such as spacing of parasitic modes or impedance, but quite often the subtleties that manifest as poor process control are hard to interpret or are nonexistence. In-process testing of transducers is time consuming for quantifying statistical aberrations, and assessments made indirectly via the workpiece are difficult. This research investigates the use of advanced Bode plot techniques to compare ultrasonic transducers with known "good" and known "bad" process performance, with the goal of a-priori process assessment. These advanced techniques expand from the basic constant voltage versus frequency sweep to include constant current and constant velocity interrogated locally on transducer or tool; they also include up and down directional frequency sweeps to quantify hysteresis effects like jumping and dropping phenomena. The investigation focuses solely on the common PZT8 piezoelectric material used with welding transducers for semiconductor wire bonding. Several metrics are investigated such as impedance, displacement/current gain, velocity/current gain, displacement/voltage gain and velocity/voltage gain. The experimental and theoretical research methods include Bode plots, admittance loops, laser vibrometry and coupled-field finite element analysis.

High temperature ultrasonic transducers for imaging and measurements in a liquid Pb/Bi eutectic alloy.

PubMed

Kazys, Rymantas; Voleisis, Algirdas; Sliteris, Reimondas; Mazeika, Liudas; Van Nieuwenhove, Rudi; Kupschus, Peter; Abderrahim, Hamid Aït

2005-04-01

In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions.

Application of PMN-32PT Piezoelectric Crystals for Novel Air-coupled Ultrasonic Transducers

NASA Astrophysics Data System (ADS)

Kazys, Rymantas Jonas; Sliteris, Reimondas; Sestoke, Justina

Due to very high piezoelectric properties of PMN-PT crystals they may significantly improve performance of air-coupled ultrasonic transducers. For these purpose vibrations of PMN-PT rectangular plates and strips were investigated. An air-coupled ultrasonic transducer and array consisting of 8 single piezoelectric strips were designed. Operation of the transducer was simulated by the finite element method using ANSYS Mechanical APDL Product Launcher software. Spatial distributions of displacements inside piezoelectric elements and matching strip were obtained. Experimental investigations were carried out by the laser Doppler vibrometer Polytec OFV-5000 and the Bruel&Kjaer microphone 4138 with the measurement amplifier NEXUS WH 3219. It was found that performance of the ultrasonic transducer with PMN-32PT crystals was a few times better than of a PZT based ultrasonic transducer.

Lithium niobate ultrasonic transducer design for Enhanced Oil Recovery.

PubMed

Wang, Zhenjun; Xu, Yuanming; Gu, Yuting

2015-11-01

Due to the strong piezoelectric effect possessed by lithium niobate, a new idea that uses lithium niobate to design high-power ultrasonic transducer for Enhanced Oil Recovery technology is proposed. The purpose of this paper is to lay the foundation for the further research and development of high-power ultrasonic oil production technique. The main contents of this paper are as follows: firstly, structure design technique and application of a new high-power ultrasonic transducer are introduced; secondly, the experiment for reducing the viscosity of super heavy oil by this transducer is done, the optimum ultrasonic parameters for reducing the viscosity of super heavy oil are given. Experimental results show that heavy large molecules in super heavy oil can be cracked into light hydrocarbon substances under strong cavitation effect caused by high-intensity ultrasonic wave. Experiment proves that it is indeed feasible to design high-power ultrasonic transducer for ultrasonic oil production technology using lithium niobate. Copyright © 2015 Elsevier B.V. All rights reserved.

Decomposition of cellulose by ultrasonic welding in water

NASA Astrophysics Data System (ADS)

Nomura, Shinfuku; Miyagawa, Seiya; Mukasa, Shinobu; Toyota, Hiromichi

2016-07-01

The use of ultrasonic welding in water to decompose cellulose placed in water was examined experimentally. Filter paper was used as the decomposition material with a horn-type transducer 19.5 kHz adopted as the ultrasonic welding power source. The frictional heat at the point where the surface of the tip of the ultrasonic horn contacts the filter paper decomposes the cellulose in the filter paper into 5-hydroxymethylfurfural (5-HMF), furfural, and oligosaccharide through hydrolysis and thermolysis that occurs in the welding process.

21 CFR 892.1570 - Diagnostic ultrasonic transducer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic ultrasonic transducer. 892.1570 Section 892.1570 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1570 Diagnostic ultrasonic transducer...

Effect of Heat Generation of Ultrasound Transducer on Ultrasonic Power Measured by Calorimetric Method

NASA Astrophysics Data System (ADS)

Uchida, Takeyoshi; Kikuchi, Tsuneo

2013-07-01

Ultrasonic power is one of the key quantities closely related to the safety of medical ultrasonic equipment. An ultrasonic power standard is required for establishment of safety. Generally, an ultrasonic power standard below approximately 20 W is established by the radiation force balance (RFB) method as the most accurate measurement method. However, RFB is not suitable for high ultrasonic power because of thermal damage to the absorbing target. Consequently, an alternative method to RFB is required. We have been developing a measurement technique for high ultrasonic power by the calorimetric method. In this study, we examined the effect of heat generation of an ultrasound transducer on ultrasonic power measured by the calorimetric method. As a result, an excessively high ultrasonic power was measured owing to the effect of heat generation from internal loss in the transducer. A reference ultrasound transducer with low heat generation is required for a high ultrasonic power standard established by the calorimetric method.

Ultrasonic monitoring of the setting of silicone elastomeric impression materials.

PubMed

Kanazawa, Tomoe; Murayama, Ryosuke; Furuichi, Tetsuya; Imai, Arisa; Suda, Shunichi; Kurokawa, Hiroyasu; Takamizawa, Toshiki; Miyazaki, Masashi

2017-01-31

This study used an ultrasonic measurement device to monitor the setting behavior of silicone elastomeric impression materials, and the influence of temperature on setting behavior was determined. The ultrasonic device consisted of a pulser-receiver, transducers, and an oscilloscope. The two-way transit time through the mixing material was divided by two to account for the down-and-back travel path; then it was multiplied by the sonic velocity. Analysis of variance and the Tukey honest significant difference test were used. In the early stages of the setting process, most of the ultrasonic energy was absorbed by the elastomers and the second echoes were relatively weak. As the elastomers hardened, the sonic velocities increased until they plateaued. The changes in sonic velocities varied among the elastomers tested, and were affected by temperature conditions. The ultrasonic method used in this study has considerable potential for determining the setting processes of elastomeric impression materials.

Ultrasonic Interferometers Revisited

ERIC Educational Resources Information Center

Greenslade, Thomas B., Jr.

2007-01-01

I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics, described a number of ultrasonic interferometers, and showed how ultrasonic transducers can be used for Fourier analysis. This time I became interested in trying the technique of using two detectors in…

High-Performance Scanning Acousto-Ultrasonic System

NASA Technical Reports Server (NTRS)

Roth, Don; Martin, Richard; Kautz, Harold; Cosgriff, Laura; Gyekenyesi, Andrew

2006-01-01

A high-performance scanning acousto-ultrasonic system, now undergoing development, is designed to afford enhanced capabilities for imaging microstructural features, including flaws, inside plate specimens of materials. The system is expected to be especially helpful in analyzing defects that contribute to failures in polymer- and ceramic-matrix composite materials, which are difficult to characterize by conventional scanning ultrasonic techniques and other conventional nondestructive testing techniques. Selected aspects of the acousto-ultrasonic method have been described in several NASA Tech Briefs articles in recent years. Summarizing briefly: The acousto-ultrasonic method involves the use of an apparatus like the one depicted in the figure (or an apparatus of similar functionality). Pulses are excited at one location on a surface of a plate specimen by use of a broadband transmitting ultrasonic transducer. The stress waves associated with these pulses propagate along the specimen to a receiving transducer at a different location on the same surface. Along the way, the stress waves interact with the microstructure and flaws present between the transducers. The received signal is analyzed to evaluate the microstructure and flaws. The specific variant of the acousto-ultrasonic method implemented in the present developmental system goes beyond the basic principle described above to include the following major additional features: Computer-controlled motorized translation stages are used to automatically position the transducers at specified locations. Scanning is performed in the sense that the measurement, data-acquisition, and data-analysis processes are repeated at different specified transducer locations in an array that spans the specimen surface (or a specified portion of the surface). A pneumatic actuator with a load cell is used to apply a controlled contact force. In analyzing the measurement data for each pair of transducer locations in the scan, the total (multimode) acousto-ultrasonic response of the specimen is utilized. The analysis is performed by custom software that extracts parameters of signals in the time and frequency domains. The computer hardware and software provide both real-time and postscan processing and display options. For example, oscilloscope displays of waveforms and power spectral densities are available in real time. Images can be computed while scanning continues. Signals can be digitally preprocessed and/or post-processed by filtering, windowing, time-segmenting, and running-waveform-averaging algorithms. In addition, the software affords options for off-line simulation of the waveform-data-acquisition and scanning processes. In tests, the system has been shown to be capable of characterizing microstructural changes and defects in SiC/SiC and C/SiC ceramic-matrix composites. Delaminations, variations in density, microstructural changes attributable to infiltration by silicon, and crack-space indications (defined in the next sentence) have been revealed in images formed from several time- and frequency-domain parameters of scanning acousto-ultrasonic signals. The crack-space indications were image features that were not revealed by other nondestructive testing methods and are so named because they turned out to mark locations where cracking eventually occurred.

Development of a novel configuration for a MEMS transducer for low bias and high resolution imaging applications

NASA Astrophysics Data System (ADS)

Emadi, Tahereh Arezoo; Buchanan, Douglas A.

2014-03-01

A robust capacitive micromachined ultrasonic transducer has been developed. In this novel configuration, a stack of two deflectable membranes are suspended over a fixed bottom electrode. Similar to conventional capacitive ultrasonic transducers, a generated electrostatic force between the electrodes causes the membranes to deflect and vibrate. However, in this new configuration the transducer effective cavity height is reduced due to the deflection of two membranes. Therefore, the transducer spring constant is more susceptible to bias voltage, which in return reduces the required bias voltage. The transducers have been produced employing a MEMS sacrificial technique where two different membrane anchoring (curved- and flat- anchors) structures, with similar membrane radii were fabricated. Highly doped polysilicon was used as the membrane material. The resonant frequencies of the two transducers have been investigated. It was found that the transducers with curved membrane anchors exhibits a larger resonant frequency shift compared to the transducers with flat membranes for a given bias voltage. Comparison has been made between the spring constant of the flat membrane transducer and that of a conventional single membrane transducer. It is shown that the multiple moving membrane transducer exhibits a larger reduction in the spring constant compared to the conventional transducer, when driven with the same bias voltage. This results in a transducer with a higher power generation capability and sensitivity.

Built-up edge investigation in vibration drilling of Al2024-T6.

PubMed

Barani, A; Amini, S; Paktinat, H; Fadaei Tehrani, A

2014-07-01

Adding ultrasonic vibrations to drilling process results in an advanced hybrid machining process, entitled "vibration drilling". This study presents the design and fabrication of a vibration drilling tool by which both rotary and vibrating motions are applied to drill simultaneously. High frequency and low amplitude vibrations were generated by an ultrasonic transducer with frequency of 19.65 kHz. Ultrasonic transducer was controlled by a MPI ultrasonic generator with 3 kW power. The drilling tool and workpiece material were HSS two-flute twist drill and Al2024-T6, respectively. The aim of this study was investigating on the effect of ultrasonic vibrations on built-up edge, surface quality, chip morphology and wear mechanisms of drill edges. Therefore, these factors were studied in both vibration and ordinary drilling. Based on the achieved results, vibration drilling offers less built-up edge and better surface quality compared to ordinary drilling. Copyright © 2014 Elsevier B.V. All rights reserved.

21 CFR 870.2880 - Ultrasonic transducer.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic transducer... ultrasonic energy that is used in conjunction with an echocardiograph to provide imaging of cardiovascular...

21 CFR 870.2880 - Ultrasonic transducer.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic transducer... ultrasonic energy that is used in conjunction with an echocardiograph to provide imaging of cardiovascular...

NEET In-Pile Ultrasonic Sensor Enablement-FY 2012 Status Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

JE Daw; JL Rempe; BR Tittmann

2012-09-01

Several Department Of Energy-Nuclear Energy (DOE-NE) programs, such as the Fuel Cycle Research and Development, Advanced Reactor Concepts, Light Water Reactor Sustainability, and Next Generation Nuclear Plant programs, are investigating new fuels and materials for advanced and existing reactors. A key objective of such programs is to understand the performance of these fuels and materials when irradiated. The Nuclear Energy Enabling Technology (NEET) Advanced Sensors and Instrumentation (ASI) in-pile instrumentation development activities are focused upon addressing cross-cutting needs for DOE-NE irradiation testing by providing higher fidelity, real-time data, with increased accuracy and resolution from smaller, compact sensors that are lessmore » intrusive. Ultrasonic technologies offer the potential to measure a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes, under harsh irradiation test conditions. There are two primary issues associated with in-pile deployment of ultrasonic sensors. The first is transducer survivability. The ability of ultrasonic transducer materials to maintain their useful properties during an irradiation must be demonstrated. The second issue is signal processing. Ultrasonic testing is typically performed in a lab or field environment, where the sensor and sample are accessible. Due to the harsh nature of in-pile testing, and the range of measurements that are desired, an enhanced signal processing capability is needed to make in-pile ultrasonic sensors viable. This project addresses these technology deployment issues.« less

Fabrication and Performance of Endoscopic Ultrasound Radial Arrays Based on PMN-PT Single Crystal/Epoxy 1-3 Composite

PubMed Central

Zhou, Dan; Cheung, Kwok Fung; Chen, Yan; Lau, Sien Ting; Zhou, Qifa; Shung, K. Kirk; Luo, Hao Su; Dai, Jiyan; Chan, Helen Lai Wa

2011-01-01

In this paper, 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single crystal/epoxy 1–3 composite was used as the active material of the endoscopic ultrasonic radial array transducer, because this composite exhibited ultrahigh electromechanical coupling coefficient (kt = 0.81%), very low mechanical quality factor (Qm = 11) and relatively low acoustic impedance (Zt = 12 MRayls). A 6.91 MHz PMN-PT/epoxy 1–3 composite radial array transducer with 64 elements was tested in a pulse-echo response measurement. The −6-dB bandwidth of the composite array transducer was 102%, which was ~30% larger than that of traditional lead zirconate titanate array transducer. The two-way insertion loss was found to be −32.3 dB. The obtained results show that this broadband array transducer is promising for acquiring high-resolution endoscopic ultrasonic images in many clinical applications. PMID:21342833

PMN-PT single crystal, high-frequency ultrasonic needle transducers for pulsed-wave Doppler application.

PubMed

Zhou, Qifa; Xu, Xiaochen; Gottlieb, Emanuel J; Sun, Lei; Cannata, Jonathan M; Ameri, Hossein; Humayun, Mark S; Han, Pengdi; Shung, K Kirk

2007-03-01

High-frequency needle ultrasound transducers with an aperture size of 0.4 mm were fabricated using lead magnesium niobate-lead titanate (PMN-33% PT) as the active piezoelectric material. The active element was bonded to a conductive silver particle matching layer and a conductive epoxy backing through direct contact curing. An outer matching layer of parylene was formed by vapor deposition. The active element was housed within a polyimide tube and a 20-gauge needle housing. The magnitude and phase of the electrical impedance of the transducer were 47 omega and -38 degrees, respectively. The measured center frequency and -6 dB fractional bandwidth of the PMN-PT needle transducer were 44 MHz and 45%, respectively. The two-way insertion loss was approximately 15 dB. In vivo high-frequency, pulsed-wave Doppler patterns of blood flow in the posterior portion and in vitro ultrasonic backscatter microscope (UBM) images of the rabbit eye were obtained with the 44-MHz needle transducer.

High density pixel array

NASA Technical Reports Server (NTRS)

McFall, James Earl (Inventor); Wiener-Avnear, Eliezer (Inventor)

2004-01-01

A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

Piezoelectric textured ceramics: Effective properties and application to ultrasonic transducers.

PubMed

Levassort, Franck; Pham Thi, Mai; Hemery, Henry; Marechal, Pierre; Tran-Huu-Hue, Louis-Pascal; Lethiecq, Marc

2006-12-22

Piezoelectric textured ceramics obtained by homo-template grain growth (HTGG) were recently demonstrated. A simple model with several assumptions has been used to calculate effective parameters of these new materials. Different connectivities have been simulated to show that spatial arrangements between the considered phases have little influence on the effective parameters, even through the 3-0 connectivity delivers the highest electromechanical thickness factor. A transducer based on a textured ceramic sample has been fabricated and characterised to show the efficiency of these piezoelectric materials. Finally, in a single element transducer configuration, simulation shows an improvement of 2 dB sensitivity for a transducer made with textured ceramic in comparison with a similar transducer design based on standard soft PZT (at equivalent bandwidths).

Piezoelectric single crystals for ultrasonic transducers in biomedical applications

PubMed Central

Zhou, Qifa; Lam, Kwok Ho; Zheng, Hairong; Qiu, Weibao; Shung, K. Kirk

2014-01-01

Piezoelectric single crystals, which have excellent piezoelectric properties, have extensively been employed for various sensors and actuators applications. In this paper, the state–of–art in piezoelectric single crystals for ultrasonic transducer applications is reviewed. Firstly, the basic principles and design considerations of piezoelectric ultrasonic transducers will be addressed. Then, the popular piezoelectric single crystals used for ultrasonic transducer applications, including LiNbO3 (LN), PMN–PT and PIN–PMN–PT, will be introduced. After describing the preparation and performance of the single crystals, the recent development of both the single–element and array transducers fabricated using the single crystals will be presented. Finally, various biomedical applications including eye imaging, intravascular imaging, blood flow measurement, photoacoustic imaging, and microbeam applications of the single crystal transducers will be discussed. PMID:25386032

Thin Wall Pipe Ultrasonic Inspection through Paint Coating

NASA Astrophysics Data System (ADS)

Predoi, Mihai Valentin; Petre, Cristian Cătălin

Classical ultrasonic inspection of welds is currently done for plates thicker than 8 mm. The inspection of but welds in thin walled pipes has considerable implementation difficulties, due to guided waves dominating ultrasonic pulses propagation. Generation of purely symmetric modes, either torsional or longitudinal, requires a circumferential uniform distribution of transducers and dedicated inspection equipment, which are increasing the inspection costs. Moreover, if the surface is paint coated, the received signals are close to the detection level. The present work implies a single transducer, coupled to the painted surface. The proper choice of the guided mode and frequency range, allows the detection of a standard, small diameter through thickness hole. In this way, the inspection of pipe welds can use the same equipment as for thick materials, with only wedge adaptation.

Assessment and Calibration of a Crimp Tool Equipped with Ultrasonic Analysis Features

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Perey, Daniel F. (Inventor); Cramer, K. Elliott (Inventor)

2013-01-01

A method is provided for calibrating ultrasonic signals passed through a crimp formed with respect to a deformable body via an ultrasonically-equipped crimp tool (UECT). The UECT verifies a crimp quality using the ultrasonic signals. The method includes forming the crimp, transmitting a first signal, e.g., a pulse, to a first transducer of the UECT, and converting the first signal, using the first transducer, into a second signal which defines an ultrasonic pulse. This pulse is transmitted through the UECT into the crimp. A second transducer converts the second signal into a third signal, which may be further conditioned, and the ultrasonic signals are calibrated using the third signal or its conditioned variant. An apparatus for calibrating the ultrasonic signals includes a pulse module (PM) electrically connected to the first and second transducers, and an oscilloscope or display electrically connected to the PM for analyzing an electrical output signal therefrom.

A novel ultrasonic clutch using near-field acoustic levitation.

PubMed

Chang, Kuo-Tsi

2004-10-01

This paper investigates design, fabrication and drive of an ultrasonic clutch with two transducers. For the two transducers, one serving as a driving element of the clutch is connected to a driving shaft via a coupling, and the other serving as a slave element of the clutch is connected to a slave shaft via another coupling. The principle of ultrasonic levitation is first expressed. Then, a series-resonant inverter is used to generate AC voltages at input terminals of each transducer, and a speed measuring system with optic sensors is used to find the relationship between rotational speed of the slave shaft and applied voltage of each transducer. Moreover, contact surfaces of the two transducers are coupled by the frictional force when both the two transducers are not energized, and separated using the ultrasonic levitation when at least one of the two transducers is energized at high voltages at resonance.

Feasibility on fiber orientation detection on unidirectional CFRP composite laminates using nondestructive evaluation techniques

NASA Astrophysics Data System (ADS)

Yang, In-Young; Kim, Ji-Hoon; Cha, Cheon-Seok; Lee, Kil-Sung; Hsu, David K.; Im, Kwang-Hee

2007-07-01

In particular, CFRP (carbon fiber reinforced plastics) composite materials have found wide applicability because of their inherent design flexibility and improved material properties. CFRP composites were manufactured from uni-direction prepreg sheet in this paper. It is important to assess fiber orientation, material properties and part defect in order to ensure product quality and structural integrity of CFRP because strength and stiffness of composites depend on fiber orientation. It is desirable to perform nondestructive evaluation which is very beneficial. An new method for nondestructively determining the fiber orientation in a composite laminate is presented. A one-sided pitch-catch setup was used in the detection and evaluation of flaws and material anomalies in the unidirectional CFRP composite laminates. Two Rayleigh wave transducers were joined head-to-head and used in the pitch-catch mode on the surface of the composites. The pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite. Especially, ultrasonic waves were extensively characterized in the CFRP composite laminates both normal to fiber and along to fiber with using a one-sided direction of Rayleigh wave transducers. Also, one-sided ultrasonic measurement was made with using a Rayleigh wave transducers and a conventional scanner was used in an immersion tank for extracting fiber orientation information from the ultrasonic reflection in the unidirectional laminate. Therefore, it is thought that the proposed method is useful to evaluate integrity of CFRP laminates.

Focal Length Controllable Ultrasonic Transducer Using Bimorph-Type Bending Actuator

NASA Astrophysics Data System (ADS)

Chae, Min-Ku; Kim, Moo-Joon; Ha, Kang-Lyeol; Lee, Chai-Bong

2003-05-01

Using a bimorph-type bending actuator, we propose a new method for controlling the focal length of a transducer by electric DC voltage. We designed two focal length controllable ultrasonic transducers with actuators, a line-focus and a point-focus transducer. The polyvinylidene fluoride (PVDF) piezoelectric type polymer film is used for transmitting and receiving of ultrasonic signals. Using the new method, it is confirmed by investigation of the underwater acoustic field that the focal length can be controlled to within 10% of the radius of the transducer curvature.

Determination of acoustic impedances of multi matching layers for narrowband ultrasonic airborne transducers at frequencies <2.5 MHz - Application of a genetic algorithm.

PubMed

Saffar, Saber; Abdullah, Amir

2012-01-01

The effective ultrasonic energy radiation into the air of piezoelectric transducers requires using multilayer matching systems with accurately selected acoustic impedances and the thickness of particular layers. One major problem of ultrasonic transducers, radiating acoustic energy into air, is to find the proper acoustic impedances of one or more matching layers. This work aims at developing an original solution to the acoustic impedance mismatch between transducer and air. If the acoustic impedance defences between transducer and air be more, then finding best matching layer(s) is harder. Therefore we consider PZT (lead zirconate titanate piezo electric) transducer and air that has huge acoustic impedance deference. The vibration source energy (PZT), which is used to generate the incident wave, consumes a part of the mechanical energy and converts it to an electrical one in theoretical calculation. After calculating matching layers, we consider the energy source as layer to design a transducer. However, this part of the mechanical energy will be neglected during the mathematical work. This approximation is correct only if the transducer is open-circuit. Since the possibilities of choosing material with required acoustic impedance are limited (the counted values cannot always be realized and applied in practice) it is necessary to correct the differences between theoretical values and the possibilities of practical application of given acoustic impedances. Such a correction can be done by manipulating other parameters of matching layers (e.g. by changing their thickness). The efficiency of the energy transmission from the piezoceramic transducer through different layers with different thickness and different attenuation enabling a compensation of non-ideal real values by changing their thickness was computer analyzed (base on genetic algorithm). Firstly, three theoretical solutions were investigated. Namely, Chebyshev, Desilets and Souquet theories. However, the obtained acoustic impedances do not necessarily correspond to a nowadays available material. Consequently, the values of the acoustic impedances are switched to the nearest values in a large material database. The switched values of the acoustic impedances do not generally give efficient transmission coefficients. Therefore, we proposed, in a second step, the use of a genetic algorithm (GA) to select the best acoustic impedances for matching layers from the material database for a narrow band ultrasonic transducer that work at frequency below the 2.5MHz by considering attenuation. However this bank is rich, the results get better. So the accuracy of the propose method increase by using a lot of materials with exact data for acoustic impedance and their attenuation, especially in high frequency. This yields highly more efficient transmission coefficient. In fact by using increasing number of layer we can increase our chance to find the best sets of materials with valuable both in acoustic impedance and low attenuation. Precisely, the transmission coefficient is almost equal to unity for the all studied cases. Finally the effect of thickness on transmission coefficient is investigated for different layers. The results showed that the transmission coefficient for air media is a function of thickness and sensitive to it even for small variation in thickness. In fact, the sensitivity increases when the differences of acoustic impedances to be high (difference between PZT and air). Copyright © 2011 Elsevier B.V. All rights reserved.

Rolling dry-coupled transducers for ultrasonic inspections of aging aircraft structures

NASA Astrophysics Data System (ADS)

Komsky, Igor N.

2004-07-01

Some advanced aircraft materials or coatings are porous or otherwise sensitive to the application of water, gel, or some other ultrasonic couplants. To overcome the problems associated with the liquid coupling medium, dry-coupled rolling modules were developed at Northwestern University for the transmission of both longitudinal and transverse ultrasonic waves at frequencies up to 10 MHz. Dry-coupled ultrasonic modules contain solid core internal stators and solid or flexible external rotors with the flexible polymer substrates. Two types of the dry-coupled modules are under development. Cylindrical base transducer modules include solid core cylindrical rotors with flexible polymer substrates that rotate around the stators with ultrasonic elements. Dry-coupled modules with elongated bases contain solid core stators and flexible track-like polymer substrates that rotate around the stators as rotors of the modules. The elongated base modules have larger contact interfaces with the inspection surface in comparison with the cylindrical base modules. Some designs of the dry-coupled rolling modules contain several ultrasonic elements with different incident angles or a variable angle unit for rapid adjustments of incident angles. The prototype dry-coupled rolling modules were integrated with the portable ultrasonic inspection systems and tested on a number of Boeing aircraft structures.

Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection

DOEpatents

Thompson, D.O.; Hsu, D.K.

1993-12-14

The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses. 25 figures.

Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection

DOEpatents

Thompson, Donald O.; Hsu, David K.

1993-12-14

The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses.

Design of advanced ultrasonic transducers for welding devices.

PubMed

Parrini, L

2001-11-01

A new high frequency ultrasonic transducer has been conceived, designed, prototyped, and tested. In the design phase, an advanced approach was used and established. The method is based on an initial design estimate obtained with finite element method (FEM) simulations. The simulated ultrasonic transducers and resonators are then built and characterized experimentally through laser interferometry and electrical resonance spectra. The comparison of simulation results with experimental data allows the parameters of FEM models to be adjusted and optimized. The achieved FEM simulations exhibit a remarkably high predictive potential and allow full control of the vibration behavior of the transducer. The new transducer is mounted on a wire bonder with a flange whose special geometry was calculated by means of FEM simulations. This flange allows the transducer to be attached on the wire bonder, not only in longitudinal nodes, but also in radial nodes of the ultrasonic field excited in the horn. This leads to a total decoupling of the transducer to the wire bonder, which has not been achieved so far. The new approach to mount ultrasonic transducers on a welding device is of major importance, not only for wire bonding, but also for all high power ultrasound applications and has been patented.

Application of IDT Sensors for Structural Health Monitoring of Windmill Turbine Blades Made of Composite Material

NASA Astrophysics Data System (ADS)

Nalladega, V.; Na, J. K.; Druffner, C.

2011-06-01

Interdigital transducers (IDT) generate and receive ultrasonic surface waves without the complexity involved with secondary devices such as angled wedges or combs. The IDT sensors have been successfully applied for the NDE of homogeneous materials like metals in order to detect cracks and de-bond. However, these transducers have not been yet adapted for complex and anisotropic materials like fiber-reinforced composites. This work presents the possibility of using IDT sensors for monitoring structural damages in wind turbine blades, typically made of fiberglass composites. IDT sensors with a range of operating frequency between 250 kHz and 1 MHz are initially tested on representative composite test panels for ultrasonic surface wave properties including beam spread, propagation distance and effect of material's anisotropy. Based on these results, an optimum frequency range for the IDT sensor is found to be 250-500 kHz. Subsequently, IDT sensors with operating frequency 500 kHz are used to detect and quantify artificial defects created in the composite test samples. Discussions are made on the interaction of ultrasonic fields with these defects along with the effects of fiber directionality and composite layer stacking.

Acousto-ultrasonic nondestructive evaluation of materials using laser beam generation and detection. M.S. Thesis

NASA Technical Reports Server (NTRS)

Huber, Robert D.; Green, Robert E., Jr.

1990-01-01

The acousto-ultrasonic method has proven to be a most interesting technique for nondestructive evaluation of the mechanical properties of a variety of materials. Use of the technique or a modification thereof, has led to correlation of the associated stress wave factor with mechanical properties of both metals and composite materials. The method is applied to the nondestructive evaluation of selected fiber reinforced structural composites. For the first time, conventional piezoelectric transducers were replaced with laser beam ultrasonic generators and detectors. This modification permitted true non-contact acousto-ultrasonic measurements to be made, which yielded new information about the basic mechanisms involved as well as proved the feasibility of making such non-contact measurements on terrestrial and space structures and heat engine components. A state-of-the-art laser based acousto-ultrasonic system, incorporating a compact pulsed laser and a fiber-optic heterodyne interferometer, was delivered to the NASA Lewis Research Center.

Method for the concurrent ultrasonic inspection of partially completed welds

DOEpatents

Johnson, John A.; Larsen, Eric D.; Miller, Karen S.; Smartt, Herschel B.; McJunkin, Timothy R.

2002-01-01

A method for the concurrent ultrasonic inspection of partially completed welds is disclosed and which includes providing a pair of transducers which are individually positioned on the opposite sides of a partially completed weld to be inspected; moving the transducers along the length of and laterally inwardly and outwardly relative to the partially completed weld; pulsing the respective transducers to produce an ultrasonic signal which passes through or is reflected from the partially completed weld; receiving from the respective transducers ultrasonic signals which pass through or are reflected from the partially completed welds; and analyzing the ultrasonic signal which has passed through or is reflected from the partially completed weld to determine the presence of any weld defects.

The ultrasonic characteristics of high frequency modulated arc and its application in material processing.

PubMed

He, Longbiao; Yang, Ping; Li, Luming; Wu, Minsheng

2014-12-01

To solve the difficulty of introducing traditional ultrasonic transducers to welding molten pool, high frequency current is used to modulate plasma arc and ultrasonic wave is excited successfully. The characteristics of the excited ultrasonic field are studied. The results show that the amplitude-frequency response of the ultrasonic emission is flat. The modulating current is the main factor influencing the ultrasonic power and the sound pressure depends on the variation of arc plasma stream force. Experimental study of the welding structure indicates grain refinement by the ultrasonic emission of the modulated arc and the test results showed there should be an energy region for the arc ultrasonic to get best welding joints. Copyright © 2014 Elsevier B.V. All rights reserved.

Acousto-ultrasonics to Assess Material and Structural Properties

NASA Technical Reports Server (NTRS)

Kautz, Harold E.

2002-01-01

This report was created to serve as a manual for applying the Acousto-Ultrasonic NDE method, as practiced at NASA Glenn, to the study of materials and structures for a wide range of applications. Three state of the art acousto-ultrasonic (A-U) analysis parameters, ultrasonic decay (UD) rate, mean time (or skewing factor, "s"), and the centroid of the power spectrum, "f(sub c)," have been studied and applied at GRC for NDE interrogation of various materials and structures of aerospace interest. In addition to this, a unique application of Lamb wave analysis is shown. An appendix gives a brief overview of Lamb Wave analysis. This paper presents the analysis employed to calculate these parameters and the development and reasoning behind their use. It also discusses the planning of A-U measurements for materials and structures to be studied. Types of transducer coupling are discussed including contact and non-contact via laser and air. Experimental planning includes matching transducer frequency range to material and geometry of the specimen to be studied. The effect on results of initially zeroing the DC component of the ultrasonic waveform is compared with not doing so. A wide range of interrogation problems are addressed via the application of these analysis parameters to real specimens is shown for five cases: Case 1: Differences in density in [0] SiC/RBSN ceramic matrix composite. Case 2: Effect of tensile fatigue cycling in [+/-45] SiC/SiC ceramic matrix composite. Case 3: Detecting creep life, and failure, in Udimet 520 Nickel-Based Super Alloy. Case 4: Detecting Surface Layer Formation in T-650-35/PMR-15 Polymer Matrix Composites Panels due to Thermal Aging. Case 5: Detecting Spin Test Degradation in PMC Flywheels. Among these cases a wide range of materials and geometries are studied.

Influence of coupling substances in the measurement of ultrasound velocity in stone materials

NASA Astrophysics Data System (ADS)

Giuzio, Beatrice; Alvarez de Buergo, Monica; Fort, Rafael; Masini, Nicola

2015-04-01

Ultrasonic (US) testing is widely applied in many fields (i.e. aviation, petrochemical, power engineering, construction and metallurgical industries). In the field of built cultural heritage and science conservation, US testing can provide the quality of the historic building materials (physic-mechanical properties), their heterogeneity/homogeinity and anisotropy, in terms of materials characterization, but also how deterioration processes can affect their quality (either after natural decay or simulation ageing tests in the laboratory). Moreover, US testing is a useful technique in evaluating the effectiveness of conservation and restoration techniques such as assessing the compatibility among original and restoration materials, identification of original quarries, and the success or not in the increase of a material cohesion when applying consolidating products. In order to obtain precise, real and reliable measurements, coupling substances between the material surface and the ultrasonic sensors are frequently used, to provide a proper contact between the transducer and the material, to assure the perfect transmission of the ultrasonic wave. Various coupling agents can be applied for this purpose. According to Wesolowski (2012), the choice of the coupling agent significantly affects the measurement of propagation velocity in material samples and, as a consequence, the US test results. In this paper, the effect of six coupling agents (medical gel used for ultrasonography, gel + parafilm, plasticine, honey, glicerine and a plastic material provided for ultrasound measurement by Panametrics) on ultrasonic measurements conducted on specific building materials is investigated on two different types of building stones (granite and dolostone from the area of Madrid, traditionally used in the construction of the built heritage, 4 stone specimens for each rock variety, 20 x 6 x 8 cm). Direct and indirect modes measuring were performed, the first one with the transducers in opposite and parallel faces of the specimens (using 500 KHz transducers), and in the second one, with both transducers in the same side (using 1 MHz transducers). In the indirect mode measurements, the distance between transducers was not fixed, but varied (5, 10, 15, 20 cm). In all cases the longitudinal wave or P wave was measured (Vp) and only in others, the transversal or S waves were registered. Furthermore, in order to assess eventual changes in the surface texture of the examined materials due to the use of the aforesaid coupling agents, and considering the specific field of cultural heritage, in which non-destructive techniques are recommended, chromatic and surface roughness tests have been performed. In this case, non destructive techniques have been used (portable spectrophotometer and optical 3D roughness meter devices). Acknowledgements: This study was possible thanks to an agreement between Instituto de Geociencias IGEO (CSIC-UCM) and Istituto per i Beni Archeologi e Monumentali IBAM (CNR), to an internship of Beatrice Giuzio (University of Potenza) at IGEO (Erasmus Placement call, EU-Lifelong Learning Programme) and to Gemoateriales 2 programme (S2013/MIT-2914) funded by the Community of Madrid. Wesołowski A., The use of biological materials as coupling agents in acoustic analyses of materials, Acta Agrophysica, 19(4), 877-886, 2012.

A study on the performance of piezoelectric composite materials for designing embedded transducers for concrete assessment

NASA Astrophysics Data System (ADS)

Dumoulin, Cédric; Deraemaeker, Arnaud

2018-03-01

Ultrasonic measurements of concrete can provide crucial information about its state of health. The most common practice in the construction industry consists in using external probes which strongly limits the use of the method since large parts of the in-service structures are difficult to access. It is also possible to assess in real time the setting process of the concrete using ultrasonic measurements. In practice, the field measurement of the concrete hardening is limited by the formworks. As an alternative, some research teams have studied the possibility to directly embed the transducers into the concrete structures. The current embedded ultrasonic transducers are of two categories: bulk piezoelectric elements surrounded by several coating and matching layers and composites piezoelectric elements. Both technologies aim at optimizing the wave energy transmitted to the tested medium. The performances of the transducers of the first kind have been studied in a previous study. A fair amount of recent research has been focused on the development of novel cement-based piezoelectric composites. In this study, we first compare the effective properties of such cement-based materials with more widespread composites made with matrices of epoxy resins or polyurethane. The study only concerns the 1-3 fiber arrangement composites. The effective properties are computed using both an analytical mixing rule method and a finite element based homogenization method using representative volume elements (RVEs) which allows for considering more realistic fiber arrangements, leading yet to very similar results. The effective piezoelectric properties of cement-based composites appear to be very low compared to composites made of epoxy or polyurethane. This result is underlined by looking at the acoustic response and the electric input impedance of different piezoelectric disks where we compare performances of such transducers with a low-cost bulk piezoelectric disc element. The first radial mode of the latter is responsible for an acoustic response of the same order of magnitude as those for the piezo-composites. This result confirms that the design of efficient low-cost embedded ultrasonic transducers can be done with such piezoceramic disks.

High density pixel array and laser micro-milling method for fabricating array

NASA Technical Reports Server (NTRS)

McFall, James Earl (Inventor); Wiener-Avnear, Eliezer (Inventor)

2003-01-01

A pixel array device is fabricated by a laser micro-milling method under strict process control conditions. The device has an array of pixels bonded together with an adhesive filling the grooves between adjacent pixels. The array is fabricated by moving a substrate relative to a laser beam of predetermined intensity at a controlled, constant velocity along a predetermined path defining a set of grooves between adjacent pixels so that a predetermined laser flux per unit area is applied to the material, and repeating the movement for a plurality of passes of the laser beam until the grooves are ablated to a desired depth. The substrate is of an ultrasonic transducer material in one example for fabrication of a 2D ultrasonic phase array transducer. A substrate of phosphor material is used to fabricate an X-ray focal plane array detector.

Ultrasonics and Optics Would Control Shot Size

NASA Technical Reports Server (NTRS)

Morrison, A. D.

1983-01-01

Feedback system assures production of silicon shot of uniform size. Breakup of silicon stream into drops is controlled, in part, by varying frequency of vibrations imparted to stream by ultrasonic transducer. Drop size monitored by photodetector. Control method particularly advantageous in that constant size is maintained even while other process variables are changed deliberately or inadvertently. Applicable to materials other than silicon.

Ultrahigh Frequency (100 MHz–300 MHz) Ultrasonic Transducers for Optical Resolution Medical Imagining

PubMed Central

Fei, Chunlong; Chiu, Chi Tat; Chen, Xiaoyang; Chen, Zeyu; Ma, Jianguo; Zhu, Benpeng; Shung, K. Kirk; Zhou, Qifa

2016-01-01

High resolution ultrasonic imaging requires high frequency wide band ultrasonic transducers, which produce short pulses and highly focused beam. However, currently the frequency of ultrasonic transducers is limited to below 100 MHz, mainly because of the challenge in precise control of fabrication parameters. This paper reports the design, fabrication, and characterization of sensitive broadband lithium niobate (LiNbO3) single element ultrasonic transducers in the range of 100–300 MHz, as well as their applications in high resolution imaging. All transducers were built for an f-number close to 1.0, which was achieved by press-focusing the piezoelectric layer into a spherical curvature. Characterization results demonstrated their high sensitivity and a −6 dB bandwidth greater than 40%. Resolutions better than 6.4 μm in the lateral direction and 6.2 μm in the axial direction were achieved by scanning a 4 μm tungsten wire target. Ultrasonic biomicroscopy images of zebrafish eyes were obtained with these transducers which demonstrate the feasibility of high resolution imaging with a performance comparable to optical resolution. PMID:27329379

Optical fiber interferometer for the study of ultrasonic waves in composite materials

NASA Technical Reports Server (NTRS)

Claus, R. O.; Zewekh, P. S.; Turner, T. M.; Wade, J. C.; Rogers, R. T.; Garg, A. O.

1981-01-01

The possibility of acoustic emission detection in composites using embedded optical fibers as sensing elements was investigated. Optical fiber interferometry, fiber acoustic sensitivity, fiber interferometer calibration, and acoustic emission detection are reported. Adhesive bond layer dynamical properties using ultrasonic interface waves, the design and construction of an ultrasonic transducer with a two dimensional Gaussian pressure profile, and the development of an optical differential technique for the measurement of surface acoustic wave particle displacements and propagation direction are also examined.

Ultrasonic Device Would Open Pipe Bombs

NASA Technical Reports Server (NTRS)

El-Raheb, Michael S.; Adams, Marc A.; Zwissler, James G.

1991-01-01

Piezoelectric ultrasonic transducer, energized by frequency generator and power supply, vibrates shell of pipe bomb while hardly disturbing explosive inner material. Frequency-control circuitry senses resonance in shell and holds generator at that frequency to induce fatigue cracking in threads of end cap. In addition to disarming bombs, ultrasonically induced fatigue may have other applications. In manufacturing, replaces some machining and cutting operations. In repair of equipment, cleanly and quickly disassembles corroded parts. In demolition of buildings used to dismember steel framework safely and controllably.

Monitoring crack extension in fracture toughness tests by ultrasonics

NASA Technical Reports Server (NTRS)

Klima, S. J.; Fisher, D. M.; Buzzard, R. J.

1975-01-01

An ultrasonic method was used to observe the onset of crack extension and to monitor continued crack growth in fracture toughness specimens during three point bend tests. A 20 MHz transducer was used with commercially available equipment to detect average crack extension less than 0.09 mm. The material tested was a 300-grade maraging steel in the annealed condition. A crack extension resistance curve was developed to demonstrate the usefulness of the ultrasonic method for minimizing the number of tests required to generate such curves.

Thermal-Independent Properties of PIN-PMN-PT Single-Crystal Linear-Array Ultrasonic Transducers

PubMed Central

Chen, Ruimin; Wu, Jinchuan; Lam, Kwok Ho; Yao, Liheng; Zhou, Qifa; Tian, Jian; Han, Pengdi; Shung, K. Kirk

2013-01-01

In this paper, low-frequency 32-element linear-array ultrasonic transducers were designed and fabricated using both ternary Pb(In1/2Nb1/2)–Pb(Mg1/3Nb2/3)–PbTiO3 (PIN-PMN-PT) and binary Pb(Mg1/3Nb2/3)–PbTiO3 (PMN-PT) single crystals. Performance of the array transducers was characterized as a function of temperature ranging from room temperature to 160°C. It was found that the array transducers fabricated using the PIN-PMN-PT single crystal were capable of satisfactory performance at 160°C, having a −6-dB bandwidth of 66% and an insertion loss of 37 dB. The results suggest that the potential of PIN-PMN-PT linear-array ultrasonic transducers for high-temperature ultrasonic transducer applications is promising. PMID:23221227

Design of an ultrasonic micro-array for near field sensing during retinal microsurgery.

PubMed

Clarke, Clyde; Etienne-Cummings, Ralph

2006-01-01

A method for obtaining the optimal and specific sensor parameters for a tool-tip mountable ultrasonic transducer micro-array is presented. The ultrasonic transducer array sensor parameters, such as frequency of operation, element size, inter-element spacing, number of elements and transducer geometry are obtained using a quadratic programming method to obtain a maximum directivity while being constrained to a total array size of 4 mm2 and the required resolution for retinal imaging. The technique is used to design a uniformly spaced NxN transducer array that is capable of resolving structures in the retina that are as small as 2 microm from a distance of 100 microm. The resultant 37x37 array of 16 microm transducers with 26 microm spacing will be realized as a Capacitive Micromachined Ultrasonic Transducer (CMUT) array and used for imaging and robotic guidance during retinal microsurgery.

High temperature ultrasonic immersion measurements using a BS-PT based piezoelectric transducer without a delay line

NASA Astrophysics Data System (ADS)

Bilgunde, Prathamesh N.; Bond, Leonard J.

2018-04-01

Ultrasonic imaging is a key enabling technology required for in-service inspection of advanced sodium fast reactors at the hot stand-by operating mode (˜250C). Current work presents development of a single element, 2.4MHz, planar, ultrasonic immersion transducer for a potential application in ranging, inspection and imaging of the reactor components. The prototype immersion transducer is first tested in water for three thermal cycles up to 92C. The transducer is further evaluated for four thermal cycles in silicone oil, with total seven thermal cycles that exceeded operation period of 21 hours. Moreover, the preliminary data acquired for speed of sound in silicone oil indicates 24% reduction from 22C to 142C. Sensitivity of the ultrasonic transducer is also measured as a function of temperature and demonstrates the effect of multiple thermal cycles on the transducer components.

Ultrasonic alignment of microparticles in nozzle-like geometries

NASA Astrophysics Data System (ADS)

Whittaker, Molly A.; Dauson, Erin R.; Parra-Raad, Jaime; Heard, Robert A.; Oppenheim, Irving J.

2018-03-01

Additive manufacturing (3-D printing) is presently limited by the mechanical properties of the materials, such as polymer resins, that are otherwise efficient and economical for part-forming. Reinforcing the resin with microscale fibers and/or particles would be an effective mechanism to achieve desired mechanical properties such as strength and ductility. Our work combines standing wave ultrasonics and microfluidics to align microparticles in devices that can act as print nozzles, based in part on our prior work with cell sorting. In this paper three different approaches are presented illustrating different engineering tradeoffs, and demonstrating laboratory results of particle alignment. First acoustic resonators are discussed, in which the ultrasonic standing waves result mostly from the mechanical properties of the microfluidic structure, excited by a piezoceramic transducer. Next non-resonant microfluidic structures are discussed, in which ultrasonic standing waves are produced directly by symmetrical transducer deployment. Finally, devices that combine nozzle-like structures, which themselves are suitable acoustic resonators, subjected to symmetrical ultrasonic excitation are presented. We will show that all three configurations will align microparticles, and discuss the tradeoffs among them for subsequent configuration of a print nozzle.

High energy, low frequency, ultrasonic transducer

DOEpatents

Brown, Albert E.

2000-01-01

A wide bandwidth, ultrasonic transducer to generate nondispersive, extensional, pulsed acoustic pressure waves into concrete reinforced rods and tendons. The wave propagation distance is limited to double the length of the rod. The transducer acoustic impedance is matched to the rod impedance for maximum transfer of acoustic energy. The efficiency of the transducer is approximately 60 percent, depending upon the type of active elements used in the transducer. The transducer input energy is, for example, approximately 1 mJ. Ultrasonic reflections will occur at points along the rod where there are changes of one percent of a wavelength in the rod diameter. A reduction in the rod diameter will reflect a phase reversed echo, as compared with the reflection from an incremental increase in diameter. Echo signal processing of the stored waveform permits a reconstruction of those echoes into an image of the rod. The ultrasonic transducer has use in the acoustic inspection of long (40+foot) architectural reinforcements and structural supporting members, such as in bridges and dams.

Design of a Smart Ultrasonic Transducer for Interconnecting Machine Applications

PubMed Central

Yan, Tian-Hong; Wang, Wei; Chen, Xue-Dong; Li, Qing; Xu, Chang

2009-01-01

A high-frequency ultrasonic transducer for copper or gold wire bonding has been designed, analyzed, prototyped and tested. Modeling techniques were used in the design phase and a practical design procedure was established and used. The transducer was decomposed into its elementary components. For each component, an initial design was obtained with simulations using a finite elements model (FEM). Simulated ultrasonic modules were built and characterized experimentally through the Laser Doppler Vibrometer (LDV) and electrical resonance spectra. Compared with experimental data, the FEM could be iteratively adjusted and updated. Having achieved a remarkably highly-predictive FEM of the whole transducer, the design parameters could be tuned for the desired applications, then the transducer is fixed on the wire bonder with a complete holder clamping was calculated by the FEM. The approach to mount ultrasonic transducers on wire bonding machines also is of major importance for wire bonding in modern electronic packaging. The presented method can lead to obtaining a nearly complete decoupling clamper design of the transducer to the wire bonder. PMID:22408564

Simulation and fabrication of 0-3 composite PZT films for ultrahigh frequency (100-300 MHz) ultrasonic transducers

NASA Astrophysics Data System (ADS)

Chen, Xiaoyang; Fei, Chunlong; Chen, Zeyu; Chen, Ruimin; Yu, Ping; Chen, Zhongping; Shung, K. Kirk; Zhou, Qifa

2016-03-01

This paper presents simulation, fabrication, and characterization of single-element ultrahigh frequency (100-300-MHz) needle ultrasonic transducers based on 0-3 composite Pb(Zr0.52Ti0.48)O3 (PZT) films prepared by using composite ceramic sol-gel film and sol-infiltration technique. The center frequency of the developed transducer at 300-MHz was the highest frequency of PbTiO3 ceramic-based ultrasonic transducers ever reported. Furthermore, a brief description of the composite model was followed by the development of a new expression for predicting the longitudinal velocity, the clamped dielectric constant, and the complex electromechanical coupling coefficient kt of these films, which is very important in ultrasonic transducer design. Moreover, these parameters are difficult to obtain by measuring the frequency dependence of impedance and phase angle because of the weak signal of the previous 0-3 composite films transducer (>100 MHz). The modeling results show that the Cubes model with a geometric factor n = 0.05 fits well with the measured data. This model will be helpful for developing the 0-3 composite systems for ultrahigh frequency ultrasonic transducer design.

Aircraft components structural health monitoring using flexible ultrasonic transducer arrays

NASA Astrophysics Data System (ADS)

Liu, W.-L.; Jen, C.-K.; Kobayashi, M.; Mrad, N.

2011-04-01

A damage detection capability based on a flexible ultrasonic transducer (FUT) array bonded onto a planar and a curved surface is presented. The FUT array was fabricated on a 75 μm titanium substrate using sol-gel spray technique. Room temperature curable adhesive is used as the bonding agent and ultrasonic couplant between the transducer and the test article. The bonding agent was successfully tested for aircraft environmental temperatures between -80 °C and 100 °C. For a planar test article, selected FUT arrays were able to detect fasteners damage within a planar distance of 176 mm, when used in the pulse-echo mode. Such results illustrate the effectiveness of the developed FUT transducer as compared to commercial 10MHz ultrasonic transducer (UT). These FUT arrays were further demonstrated on a curved test article. Pulse-echo measurements confirmed the reflected echoes from the specimen. Such measurement was not possible with commercial UTs due to the curved nature of the test article and its accessibility, thus demonstrating the suitability and superiority of the developed flexible ultrasonic transducer capability.

Ultrasonic characterization of damage in a simulated CF-18 composite structure

NASA Astrophysics Data System (ADS)

McRae, K. I.; Finlayson, R. D.; Sturrock, W. R.; Liesch, D. S.

1993-02-01

A simulated CF-18 aircraft door component was constructed and subjected to treatment during manufacturing with the object of inducing damage in the composite material in a known and well-defined manner. The simulated component was then sent to participants in a nondestructive evaluation study. Results are reported for tests conducted with a scanning apparatus and data acquisition system which consisted of three components: ultrasonic transducer and scanner comprising a two-axis scanning frame to which a modified commercial transducer was attached; an acquisition system for ultrasonic data known as Signal Processing Ultrasonic Device (SPUD); and a data analysis and display system (DETECT/NDE) specifically designed to manipulate large three dimensional ultrasonic data sets. A series of five large-area scans was performed, each scan about 52 cm square. A total of eight regions of interest were identified for a more detailed analysis of the delamination damage, seven detailed scans covering a 13-cm square and one covering a 20.8-cm square. It was often possible to identify the probable source of the damage as that resulting from impact or caused by overloading of fasteners. Flaws of all significant dimensions were located and fully characterized using the ultrasonic procedure.

Micromachined capacitive ultrasonic immersion transducer array

NASA Astrophysics Data System (ADS)

Jin, Xuecheng

Capacitive micromachined ultrasonic transducers (cMUTs) have emerged as an attractive alternative to conventional piezoelectric ultrasonic transducers. They offer performance advantages of wide bandwidth and sensitivity that have heretofore been attainable. In addition, micromachining technology, which has benefited from the fast-growing microelectronics industry, enables cMUT array fabrication and electronics integration. This thesis describes the design and fabrication of micromachined capacitive ultrasonic immersion transducer arrays. The basic transducer electrical equivalent circuit is derived from Mason's theory. The effects of Lamb waves and Stoneley waves on cross coupling and acoustic losses are discussed. Electrical parasitics such as series resistance and shunt capacitance are also included in the model of the transducer. Transducer fabrication technology is systematically studied. Device dimension control in both vertical and horizontal directions, process alternatives and variations in membrane formation, via etch and cavity sealing, and metalization as well as their impact on transducer performance are summarized. Both 64 and 128 element 1-D array transducers are fabricated. Transducers are characterized in terms of electrical input impedance, bandwidth, sensitivity, dynamic range, impulse response and angular response, and their performance is compared with theoretical simulation. Various schemes for cross coupling reduction is analyzed, implemented, and verified with both experiments and theory. Preliminary results of immersion imaging are presented using 64 elements 1-D array transducers for active source imaging.

Influence of Ultrasonic Nonlinear Propagation on Hydrophone Calibration Using Two-Transducer Reciprocity Method

NASA Astrophysics Data System (ADS)

Yoshioka, Masahiro; Sato, Sojun; Kikuchi, Tsuneo; Matsuda, Yoichi

2006-05-01

In this study, the influence of ultrasonic nonlinear propagation on hydrophone calibration by the two-transducer reciprocity method is investigated quantitatively using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. It is proposed that the correction for the diffraction and attenuation of ultrasonic waves used in two-transducer reciprocity calibration can be derived using the KZK equation to remove the influence of nonlinear propagation. The validity of the correction is confirmed by comparing the sensitivities calibrated by the two-transducer reciprocity method and laser interferometry.

Development of an ultrasonic inspection robot using an electromagnetic acoustic transducer for a Lamb wave and an SH-plate wave.

PubMed

Murayama, Riichi; Makiyama, Shunnichi; Kodama, Mitutoshi; Taniguchi, Yasutoshi

2004-04-01

For inspection of a storage tank and pipeline in service, the application of an automatic inspection system (nondestructive inspection robot) is desirable, because manual inspection is difficult to perfectly and exactly perform due to the enormous amount of inspection needed. However, an ultrasonic nondestructive inspection robot with a piezoelectric oscillator needs to touch only the material surface to be directly inspected using a coupling medium. That is, the material surface and the sensor must always be held by constant pressure in the vertical direction on the material side. Actually, it is difficult to overcome these problems; thus an ultrasonic inspection robot could not be widely applied. We then tried to develop an ultrasonic inspection robot with an electromagnetic acoustic transducer (EMAT) which did not require a coupling medium to inspect the circumferential pipe parts. We developed a special EMAT that could transmit and receive alternately a Lamb wave with high sensitivity and a SH-plate wave without influence by the welded part. The method by which the inspection robot turned around the direction of the steel pipe surroundings was executed by observing the tape pasted in the direction of the steel pipe surroundings with an installed CCD camera. In this report, the basic mechanism of this inspection robot and an examination of results are described.

Scaling up the Single Transducer Thickness-Independent Ultrasonic Imaging Method for Accurate Characterization of Microstructural Gradients in Monolithic and Composite Tubular Structures

NASA Technical Reports Server (NTRS)

Roth, Don J.; Carney, Dorothy V.; Baaklini, George Y.; Bodis, James R.; Rauser, Richard W.

1998-01-01

Ultrasonic velocity/time-of-flight imaging that uses back surface reflections to gauge volumetric material quality is highly suited for quantitative characterization of microstructural gradients including those due to pore fraction, density, fiber fraction, and chemical composition variations. However, a weakness of conventional pulse-echo ultrasonic velocity/time-of-flight imaging is that the image shows the effects of thickness as well as microstructural variations unless the part is uniformly thick. This limits this imaging method's usefulness in practical applications. Prior studies have described a pulse-echo time-of-flight-based ultrasonic imaging method that requires using a single transducer in combination with a reflector plate placed behind samples that eliminates the effect of thickness variation in the image. In those studies, this method was successful at isolating ultrasonic variations due to material microstructure in plate-like samples of silicon nitride, metal matrix composite, and polymer matrix composite. In this study, the method is engineered for inspection of more complex-shaped structures-those having (hollow) tubular/curved geometry. The experimental inspection technique and results are described as applied to (1) monolithic mullite ceramic and polymer matrix composite 'proof-of-concept' tubular structures that contain machined patches of various depths and (2) as-manufactured monolithic silicon nitride ceramic and silicon carbide/silicon carbide composite tubular structures that might be used in 'real world' applications.

Introduction to special session on "ultrasonic transducers for harsh environments

NASA Astrophysics Data System (ADS)

Tittmann, B. R.; Reinhardt, B.; Daw, J.

2018-04-01

This work describes the results of experiments conducted as part of an instrumented lead test in-core in a nuclear reactor with the piezoelectric and magnetostrictive materials. The experiments exposed AlN, ZnO, BiT, Remendur, and Galfenol to more neutron radiation than found in the literature. The magnetostrictive sensors produce stable ultrasonic pulse-echoes throughout much of the irradiation. The BiT transducers could operate up until approximate 5 × 10^20 n/cm^2 (E>1MeV). The piezoelectric AlN operated well during the entire experiment. The results imply that now available are candidates for operation in harsh environments found in nuclear reactors and steam generator plants.

An absolute method for determination of misalignment of an immersion ultrasonic transducer.

PubMed

Narayanan, M M; Singh, Narender; Kumar, Anish; Babu Rao, C; Jayakumar, T

2014-12-01

An absolute methodology has been developed for quantification of misalignment of an ultrasonic transducer using a corner-cube retroreflector. The amplitude based and the time of flight (TOF) based C-scans of the reflector are obtained for various misalignments of the transducer. At zero degree orientation of the transducer, the vertical positions of the maximum amplitude and the minimum TOF in the C-scan coincide. At any other orientation of the transducer with the horizontal plane, there is a vertical shift in the position of the maximum amplitude with respect to the minimum TOF. The position of the minimum (TOF) remains the same irrespective of the orientation of the transducer and hence is used as a reference for any misalignment of the transducer. With the measurement of the vertical shift and the horizontal distance between the transducer and the vertex of the reflector, the misalignment of the transducer is quantified. Based on the methodology developed in the present study, retroreflectors are placed in the Indian 500MWe Prototype Fast Breeder Reactor for assessment of the orientation of the ultrasonic transducer prior to the under-sodium ultrasonic scanning for detection of any protrusion of the subassemblies. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of ultrasound techniques for brain injury detection

NASA Astrophysics Data System (ADS)

Mobley, Joel; Kasili, Paul M.; Norton, Stephen J.; Vo-Dinh, Tuan

1998-05-01

In this work, we examine the physics underlying wave propagation in the head to evaluate various ultrasonic transducers for use in a brian injury detection device. The results of measurements of the attenuation coefficient and phase velocity for ultrasonic propagation in samples of brain tissue and skull bone from sheep are presented. The material properties are then used to investigate the propagation of ultrasonic pressure fields in the head. The ultrasound fields for three different transducers are calculated for propagation in a simulated brain/skull model. The model is constructed using speed-of-sound and mass density values of the two tissue types. The impact of the attenuation on the ultrasound fields is then examined. Finally, the relevant points drawn from these discussions are summarized. We hope to minimize the confounding effects of the skull by using sub-MHz ultrasound while maintaining the necessary temporal and spatial resolution to successfully detect injury in the brain.

A micro-machined source transducer for a parametric array in air.

PubMed

Lee, Haksue; Kang, Daesil; Moon, Wonkyu

2009-04-01

Parametric array applications in air, such as highly directional parametric loudspeaker systems, usually rely on large radiators to generate the high-intensity primary beams required for nonlinear interactions. However, a conventional transducer, as a primary wave projector, requires a great deal of electrical power because its electroacoustic efficiency is very low due to the large characteristic mechanical impedance in air. The feasibility of a micro-machined ultrasonic transducer as an efficient finite-amplitude wave projector was studied. A piezoelectric micro-machined ultrasonic transducer array consisting of lead zirconate titanate uni-morph elements was designed and fabricated for this purpose. Theoretical and experimental evaluations showed that a micro-machined ultrasonic transducer array can be used as an efficient source transducer for a parametric array in air. The beam patterns and propagation curves of the difference frequency wave and the primary wave generated by the micro-machined ultrasonic transducer array were measured. Although the theoretical results were based on ideal parametric array models, the theoretical data explained the experimental results reasonably well. These experiments demonstrated the potential of micro-machined primary wave projector.

Bulk ultrasonic NDE of metallic components at high temperature using magnetostrictive transducers

NASA Astrophysics Data System (ADS)

Ashish, Antony Jacob; Rajagopal, Prabhu; Balasubramaniam, Krishnan; Kumar, Anish; Rao, B. Purnachandra; Jayakumar, Tammana

2017-02-01

Online ultrasonic NDE at high-temperature is of much interest to the power, process and automotive industries in view of possible savings in downtime. This paper describes a novel approach to developing ultrasonic transducers capable of high-temperature in-situ operation using the principle of magnetostriction. Preliminary design from previous research by the authors [1] is extended for operation at 1 MHz, and at elevated temperatures by amorphous metallic strips as the magnetostrictive core. Ultrasonic signals in pulse-echo mode are experimentally obtained from the ultrasonic transducer thus developed, in a simulated high-temperature environment of 350 °C for 10 hours. Advantages and challenges for practical deployment of this approach are discussed.

Ultrasonic probe system for the bore-side inspection of tubes and welds therein

DOEpatents

Cook, K. Von; Koerner, Dan W.; Cunningham, Jr., Robert A.; Murrin, Jr., Horace T.

1977-07-26

A probe system is provided for the bore-side inspection of tube-to-header welds and the like for small diameter tubes. The probe head of the system includes an ultrasonic transmitter-receiver transducer, a separate ultrasonic receiver, a reflector associated with the transducer to properly orient the ultrasonic signal with respect to a tube wall, a baffle to isolate the receiver from the transducer, and means for maintaining the probe head against the tube wall under investigation. Since the probe head must rotate to inspect along a helical path, special ultrasonic signal connections are employed. Through the use of the probe, flaws at either the inner or outer surfaces may be detected.

Modal simulation analysis of novel 3D elliptical ultrasonic transducer

NASA Astrophysics Data System (ADS)

Kurniawan, R.; Ali, S.; Ko, T. J.

2018-03-01

This paper aims to present the modal simulation analysis results of a novel 3D elliptical ultrasonic transducer. This research aims to develop a novel elliptical transducer that works in ultrasonic and is able to generate a three dimensional motion in Cartesian space. The concept of the transducer design is basically to find a coupling frequency of the longitudinal-bending-bending mode. To achieve that purpose, the modal simulation analysis was performed to find a proper dimension of the transducer, thus the natural frequency of the 1st longitudinal mode is much closed with the two of natural frequency of the 3rd bending mode. The finite element modelling (FEM) was used to perform this work.

Apparatus for checking the direction of polarization of shear-wave ultrasonic transducers

DOEpatents

Karplus, Henry H. B.

1980-01-01

An apparatus for checking the direction of polarization of shear-wave ultrasonic transducers comprises a first planar surface for mounting the shear-wave transducer, a second planar surface inclined at a predetermined angle to the first surface to generate longitudinal waves by mode conversion, and a third planar surface disposed at a second predetermined angle to the first for mounting a longitudinal-wave ultrasonic transducer. In an alternate embodiment, two second planar surfaces at the predetermined angle are placed at an angle to each other. The magnitude of the shear wave is a function of the angle between the direction of polarization of the transducer and the mode-conversion surface.

Noncontact Determination of Antisymmetric Plate Wave Velocity in Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Kautz, Harold E.

1998-01-01

High-temperature materials are of increasing importance in the development of more efficient engines and components for the aeronautics industry. In particular, ceramic matrix composite (CMC) and metal matrix composite (MMC) structures are under active development for these applications. The acousto-ultrasonic (AU) method has been shown to be useful for assessing mechanical properties in composite structures. In particular, plate wave analysis can characterize composites in terms of their stiffness moduli. It is desirable to monitor changes in mechanical properties that occur during thermomechanical testing and to monitor the health of components whose geometry or position make them hard to reach with conventional ultrasonic probes. In such applications, it would be useful to apply AU without coupling directly to the test surface. For a number of years, lasers have been under investigation as remote ultrasonic input sources and ultrasound detectors. The use of an ultrasonic transducer coupled through an air gap has also been under study. So far at the NASA Lewis Research Center, we have been more successful in using lasers as ultrasonic sources than as output devices. On the other hand, we have been more successful in using an air-coupled piezoelectric transducer as an output device than as an input device. For this reason, we studied the laser in/air-coupled-transducer out combination-using a pulsed NdYAG laser as the ultrasonic source and an air-coupled-transducer as the detector. The present work is focused on one of the AU parameters of interest, the ultrasonic velocity of the antisymmetric plate-wave mode. This easily identified antisymmetric pulse can be used to determine shear and flexure modulus. It was chosen for this initial work because the pulse arrival times are likely to be the most precise. The following schematic illustrates our experimental arrangement for using laser in/air-transducer out on SiC/SiC composite tensile specimens. The NdYAG pulse was directed downward by a 90 infrared prism to the top of the specimen, but at the edge of one end. An energy sensor measured a single pulse at 13 millijoules (mJ) before it passed through the prism, which attenuated 15 percent of its energy. It also provided an output trigger for the waveform time-delay synthesizer.

Study of ultrasonic thermometry based on ultrasonic time-of-flight measurement

NASA Astrophysics Data System (ADS)

Jia, Ruixi; Xiong, Qingyu; Wang, Lijie; Wang, Kai; Shen, Xuehua; Liang, Shan; Shi, Xin

2016-03-01

Ultrasonic thermometry is a kind of acoustic pyrometry and it has been evolving as a new temperature measurement technology for various environment. However, the accurate measurement of the ultrasonic time-of-flight is the key for ultrasonic thermometry. In this paper, we study the ultrasonic thermometry technique based on ultrasonic time-of-flight measurement with a pair of ultrasonic transducers for transmitting and receiving signal. The ultrasonic transducers are installed in a single path which ultrasonic travels. In order to validate the performance of ultrasonic thermometry, we make a contrast about the absolute error between the measured temperature value and the practical one. With and without heater source, the experimental results indicate ultrasonic thermometry has high precision of temperature measurement.

Energy shadowing correction of ultrasonic pulse-echo records by digital signal processing

NASA Technical Reports Server (NTRS)

Kishonio, D.; Heyman, J. S.

1985-01-01

A numerical algorithm is described that enables the correction of energy shadowing during the ultrasonic testing of bulk materials. In the conventional method, an ultrasonic transducer transmits sound waves into a material that is immersed in water so that discontinuities such as defects can be revealed when the waves are reflected and then detected and displayed graphically. Since a defect that lies behind another defect is shadowed in that it receives less energy, the conventional method has a major drawback. The algorithm normalizes the energy of the incoming wave by measuring the energy of the waves reflected off the water/air interface. The algorithm is fast and simple enough to be adopted for real time applications in industry. Images of material defects with the shadowing corrections permit more quantitative interpretation of the material state.

Analysis of a Non-resonant Ultrasonic Levitation Device

NASA Astrophysics Data System (ADS)

Andrade, Marco A. B.; Pérez, Nicolás; Adamowski, Julio C.

In this study, a non-resonant configuration of ultrasonic levitation device is presented, which is formed by a small diameter ultrasonic transducer and a concave reflector. The influence of different levitator parameters on the levitation performance is investigated by using a numerical model that combines the Gor'kov theory with a matrix method based on the Rayleigh integral. In contrast with traditional acoustic levitators, the non-resonant ultrasonic levitation device allows the separation distance between the transducer and the reflector to be adjusted continually, without requiring the separation distance to be set to a multiple of half-wavelength. It is also demonstrated, both numerically and experimentally, that the levitating particle can be manipulated by maintaining the transducer in a fixed position in space and moving the reflector in respect to the transducer.

High resolution, high sensitivity, dynamic distributed structural monitoring using optical frequency domain reflectometry

NASA Astrophysics Data System (ADS)

Kreger, Stephen T.; Sang, Alex K.; Garg, Naman; Michel, Julia

2013-05-01

Fiber-optic ultrasonic transducers are an important component of an active ultrasonic testing system for structural health monitoring. Fiber-optic transducers have several advantages such as small size, light weight, and immunity to electromagnetic interference that make them much more attractive than the current available piezoelectric transducers, especially as embedded and permanent transducers in active ultrasonic testing for structural health monitoring. In this paper, a distributed fiber-optic laser-ultrasound generation based on the ghost-mode of tilted fiber Bragg gratings is studied. The influences of the laser power and laser pulse duration on the laser-ultrasound generation are investigated. The results of this paper are helpful to understand the working principle of this laser-ultrasound method and improve the ultrasonic generation efficiency.

Study of distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Tian, Jiajun; Zhang, Qi; Han, Ming

2013-05-01

Fiber-optic ultrasonic transducers are an important component of an active ultrasonic testing system for structural health monitoring. Fiber-optic transducers have several advantages such as small size, light weight, and immunity to electromagnetic interference that make them much more attractive than the current available piezoelectric transducers, especially as embedded and permanent transducers in active ultrasonic testing for structural health monitoring. In this paper, a distributed fiber-optic laser-ultrasound generation based on the ghost-mode of tilted fiber Bragg gratings is studied. The influences of the laser power and laser pulse duration on the laser-ultrasound generation are investigated. The results of this paper are helpful to understand the working principle of this laser-ultrasound method and improve the ultrasonic generation efficiency.

Ultrasound Analysis of Slurries

DOEpatents

Soong, Yee and Blackwell, Arthur G.

2005-11-01

An autoclave reactor allows for the ultrasonic analysis of slurry concentration and particle size distribution at elevated temperatures and pressures while maintaining the temperature- and pressure-sensitive ultrasonic transducers under ambient conditions. The reactor vessel is a hollow stainless steel cylinder containing the slurry which includes a stirrer and a N, gas source for directing gas bubbles through the slurry. Input and output transducers are connected to opposed lateral portions of the hollow cylinder for respectively directing sound waves through the slurry and receiving these sound waves after transmission through the slurry, where changes in sound wave velocity and amplitude can be used to measure slurry parameters. Ultrasonic adapters connect the transducers to the reactor vessel in a sealed manner and isolate the transducers from the hostile conditions within the vessel without ultrasonic signal distortion or losses.

Ultrasound Analysis Of Slurries

DOEpatents

Soong, Yee; Blackwell, Arthur G.

2005-11-01

An autoclave reactor allows for the ultrasonic analysis of slurry concentration and particle size distribution at elevated temperatures and pressures while maintaining the temperature- and pressure-sensitive ultrasonic transducers under ambient conditions. The reactor vessel is a hollow stainless steel cylinder containing the slurry which includes a stirrer and a N.sub.2 gas source for directing gas bubbles through the slurry. Input and output transducers are connected to opposed lateral portions of the hollow cylinder for respectively directing sound waves through the slurry and receiving these sound waves after transmission through the slurry, where changes in sound wave velocity and amplitude can be used to measure slurry parameters. Ultrasonic adapters connect the transducers to the reactor vessel in a sealed manner and isolate the transducers from the hostile conditions within the vessel without ultrasonic signal distortion or losses.

Two-Element Transducer for Ultrasound

NASA Technical Reports Server (NTRS)

Lecroissette, D. H.; Heyser, R. C.

1986-01-01

Separation of transmitting and receiving units improves probing of deep tissue. Ultrasonic transducer has dual elements to increase depth at which sonic images are made of biological tissue. Transducer uses separate transmitting and receiving elements, and frequency response of receiving element independently designed to accommodate attenuation of higher frequencies by tissue. New transducer intended for pulse-echo ultrasonic systems in which reflected sound pulses reveal features in tissue.

Acoustic devices for particle and cell manipulation and sensing.

PubMed

Qiu, Yongqiang; Wang, Han; Demore, Christine E M; Hughes, David A; Glynne-Jones, Peter; Gebhardt, Sylvia; Bolhovitins, Aleksandrs; Poltarjonoks, Romans; Weijer, Kees; Schönecker, Andreas; Hill, Martyn; Cochran, Sandy

2014-08-13

An emerging demand for the precise manipulation of cells and particles for applications in cell biology and analytical chemistry has driven rapid development of ultrasonic manipulation technology. Compared to the other manipulation technologies, such as magnetic tweezing, dielectrophoresis and optical tweezing, ultrasonic manipulation has shown potential in a variety of applications, with its advantages of versatile, inexpensive and easy integration into microfluidic systems, maintenance of cell viability, and generation of sufficient forces to handle particles, cells and their agglomerates. This article briefly reviews current practice and reports our development of various ultrasonic standing wave manipulation devices, including simple devices integrated with high frequency (>20 MHz) ultrasonic transducers for the investigation of biological cells and complex ultrasonic transducer array systems to explore the feasibility of electronically controlled 2-D and 3-D manipulation. Piezoelectric and passive materials, fabrication techniques, characterization methods and possible applications are discussed. The behavior and performance of the devices have been investigated and predicted with computer simulations, and verified experimentally. Issues met during development are highlighted and discussed. To assist long term practical adoption, approaches to low-cost, wafer level batch-production and commercialization potential are also addressed.

Acoustic Devices for Particle and Cell Manipulation and Sensing

PubMed Central

Qiu, Yongqiang; Wang, Han; Demore, Christine E. M.; Hughes, David A.; Glynne-Jones, Peter; Gebhardt, Sylvia; Bolhovitins, Aleksandrs; Poltarjonoks, Romans; Weijer, Kees; Schönecker, Andreas; Hill, Martyn; Cochran, Sandy

2014-01-01

An emerging demand for the precise manipulation of cells and particles for applications in cell biology and analytical chemistry has driven rapid development of ultrasonic manipulation technology. Compared to the other manipulation technologies, such as magnetic tweezing, dielectrophoresis and optical tweezing, ultrasonic manipulation has shown potential in a variety of applications, with its advantages of versatile, inexpensive and easy integration into microfluidic systems, maintenance of cell viability, and generation of sufficient forces to handle particles, cells and their agglomerates. This article briefly reviews current practice and reports our development of various ultrasonic standing wave manipulation devices, including simple devices integrated with high frequency (>20 MHz) ultrasonic transducers for the investigation of biological cells and complex ultrasonic transducer array systems to explore the feasibility of electronically controlled 2-D and 3-D manipulation. Piezoelectric and passive materials, fabrication techniques, characterization methods and possible applications are discussed. The behavior and performance of the devices have been investigated and predicted with computer simulations, and verified experimentally. Issues met during development are highlighted and discussed. To assist long term practical adoption, approaches to low-cost, wafer level batch-production and commercialization potential are also addressed. PMID:25123465

Actively adjustable step-type ultrasonic horns in longitudinal vibration

NASA Astrophysics Data System (ADS)

Lin, Shuyu; Guo, Hao; Xu, Jie

2018-04-01

Actively adjustable longitudinal step-type ultrasonic horns are proposed and studied. The horn is composed of a traditional ultrasonic horn and piezoelectric material. In practical applications, this kind of step-type ultrasonic horn is mechanically excited by an ultrasonic transducer and the piezoelectric material is connected to an adjustable electric impedance. In this research, the effects of the electric impedance and of the location of the piezoelectric material on the performance of the horn are studied. It is shown that when the electric resistance is increased, the resonance frequency of the horn is increased; the displacement magnification is increased when the piezoelectric material is located in the large end and decreased when the piezoelectric material is located in the small end of the horn. The displacement magnification for the piezoelectric material in the large end is larger than that for the piezoelectric material in the small end of the horn. Some step-type ultrasonic horns are designed and manufactured; the resonance frequency and the displacement magnification are measured by means of POLYTEC Laser Scanning vibrometer. It is shown that the theoretical resonance frequency and the displacement magnification are in good agreement with the measured results. It is concluded that by means of the insertion of the piezoelectric material in the longitudinal horn, the horn performance can be adjusted by changing the electric impedance and the location of the piezoelectric material in the horn. It is expected that this kind of adjustable ultrasonic horns can be used in traditional and potential ultrasonic technologies where the vibrational performance adjustment is needed.

Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

NASA Astrophysics Data System (ADS)

Reinhardt, Brian; Tittmann, Bernhard; Rempe, Joy; Daw, Joshua; Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov; Ramuhalli, Pradeep; Montgomery, Robert; Chien, Hualte; Wernsman, Bernard

2015-03-01

Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two magnetostrictive transducers were fabricated with Remendur or Galfenol as the active elements. Pulse-echo ultrasonic measurements of these transducers are made in-situ. This paper will present an overview of the test design including selection criteria for candidate materials and optimization of test assembly parameters, data obtained from both out-of-pile and in-pile testing at elevated temperatures, and an assessment based on initial data of the expected performance of ultrasonic devices in irradiation conditions.

A new topological structure for the Langevin-type ultrasonic transducer.

PubMed

Lu, Xiaolong; Hu, Junhui; Peng, Hanmin; Wang, Yuan

2017-03-01

In this paper, a new topological structure for the Langevin-type ultrasonic transducer is proposed and investigated. The two cylindrical terminal blocks are conically shaped with four supporting plates each, and two cooling fins are disposed at the bottom of terminal blocks, adjacent to the piezoelectric rings. Experimental results show that it has larger vibration velocity, lower temperature rise and higher electroacoustic energy efficiency than the conventional Langevin transducer. The reasons for the phenomena can be well explained by the change of mass, heat dissipation surface and force factor of the transducer. The proposed design may effectively improve the performance of ultrasonic transducers, in terms of the working effect, energy consumption and working life. Copyright © 2016 Elsevier B.V. All rights reserved.

On-line ultrasonic gas entrainment monitor

DOEpatents

Day, Clifford K.; Pedersen, Herbert N.

1978-01-01

Apparatus employing ultrasonic energy for detecting and measuring the quantity of gas bubbles present in liquids being transported through pipes. An ultrasonic transducer is positioned along the longitudinal axis of a fluid duct, oriented to transmit acoustic energy radially of the duct around the circumference of the enclosure walls. The back-reflected energy is received centrally of the duct and interpreted as a measure of gas entrainment. One specific embodiment employs a conical reflector to direct the transmitted acoustic energy radially of the duct and redirect the reflected energy back to the transducer for reception. A modified embodiment employs a cylindrical ultrasonic transducer for this purpose.

Stress wave attenuation in thin structures by ultrasonic through-transmission

NASA Technical Reports Server (NTRS)

Lee, S. S.; Williams, J. H., Jr.

1980-01-01

The steady state amplitude of the output of an ultrasonic through transmission measurement is analyzed and the result is given in closed form. Provided that the product of the input and output transduction ratios; the specimen-transducer reflection coefficient; the specimen-transducer phase shift parameter; and the material phase velocity are known, this analysis gives a means for determining the through-thickness attenuation of an individual thin sample. Multiple stress wave reflections are taken into account and so signal echoes do not represent a difficulty. An example is presented for a graphite fiber epoxy composite (Hercules AS/3501-6). A direct method for continuous or intermittent monitoring of through thickness attenuation of plate structures which may be subject to service structural degradation is provided.

Feasibility on Ultrasonic Velocity using Contact and Non-Contact Nondestructive Techniques for Carbon/Carbon Composites

NASA Astrophysics Data System (ADS)

Im, K. H.; Chang, M.; Hsu, D. K.; Song, S. J.; Cho, H.; Park, J. W.; Kweon, Y. S.; Sim, J. K.; Yang, I. Y.

2007-03-01

Advanced materials are to be required to have specific functions associated with extremely environments. One of them is carbon/carbon(C/C) composite material, which has obvious advantages over conventional materials. The C/Cs have become to be utilized as parts of aerospace applications and its low density, high thermal conductivity and excellent mechanical properties at elevated temperatures make it an ideal material for aircraft brake disks. Because of permeation of coupling medium such as water, it is desirable to perform contact-less nondestructive evaluation to assess material properties and part homogeneity. In this work, a C/C composite material was characterized with non-contact and contact ultrasonic methods using a scanner with automatic-data acquisition function. Also through transmission mode was performed because of the main limitation for air-coupled transducers, which is the acoustic impedance mismatch between most materials and air. Especially ultrasonic images and velocities for C/C composite disk brake were compared and found to be consistent to some degree with the non-contact and contact ultrasonic measurement methods. Low frequency through-transmission scans based on both amplitude of the ultrasonic pulse was used for mapping out the material property inhomogeneity. Measured results were compared with those obtained by the dry-coupling ultrasonic UT system and through transmission method in immersion. Finally, feasibility has been found to measure and compare ultrasonic velocities of C/C composites with using the contact/noncontact peak-delay measurement method based on the pulse overlap method.

Transducer Joint for Kidney-Stone Ultrasonics

NASA Technical Reports Server (NTRS)

Angulo, E. D.

1983-01-01

Ultrasonic therapy for kidney stones improved by new way of connecting wire-probe ultrasonic waveguide to transducer. Improved mounting allows joint to last long enough for effective treatment. Sheath and rubber dampers constrain lateral vibration of wire waveguide. Combination of V-shaped mounting groove, sheath, and rubber dampers increases life expectancy of wire 15 times or more.

MOSFET-based high voltage short pulse generator for ultrasonic transducer excitation

NASA Astrophysics Data System (ADS)

Hidayat, Darmawan; Setianto, Syafei, Nendi Suhendi; Wibawa, Bambang Mukti

2018-02-01

This paper presents the generation of a high-voltage short pulse for the excitation of high frequency ultrasonic transducers. This is highly required in the purpose of various ultrasonic-based evaluations, particularly when high resolution measurement is necessary. A high voltage (+760 V) DC voltage source was pulsated by an ultrafast switching MOSFET which was driven by a pulse generator circuit consisting of an astable multivibrator, a one-shot multivibrator with Schmitt trigger input and a high current MOSFET driver. The generated pulses excited a 200-kHz and a 1-MHz ultrasonic transducers and tested in the transmission mode propagation to evaluate the performances of the generated pulse. The test results showed the generator were able to produce negative spike pulses up to -760 V voltage with the shortest time-width of 107.1 nanosecond. The transmission-received ultrasonic waves show frequency oscillation at 200 and 961 kHz and their amplitudes varied with the voltage of excitation pulse. These results conclude that the developed pulse generator is applicable to excite transducer for the generation of high frequency ultrasonic waves.

A capacitive ultrasonic transducer based on parametric resonance.

PubMed

Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F

2017-07-24

A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of f o . When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2f o with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at f o frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

High Temperature, High Power Piezoelectric Composite Transducers

PubMed Central

Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

2014-01-01

Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

Improving Plating by Use of Intense Acoustic Beams

NASA Technical Reports Server (NTRS)

Oeftering, Richard C.; Denofrio, Charles

2003-01-01

An improved method of selective plating of metals and possibly other materials involves the use of directed high-intensity acoustic beams. The beams, typically in the ultrasonic frequency range, can be generated by fixed-focus transducers (see figure) or by phased arrays of transducers excited, variously, by continuous waves, tone bursts, or single pulses. The nonlinear effects produced by these beams are used to alter plating processes in ways that are advantageous.

Airborne ultrasonic phased arrays using ferroelectrets: a new fabrication approach.

PubMed

Ealo, Joao L; Camacho, Jorge J; Fritsch, Carlos

2009-04-01

In this work, a novel procedure that considerably simplifies the fabrication process of ferroelectret-based multielement array transducers is proposed and evaluated. Also, the potential of ferroelectrets being used as active material for air-coupled ultrasonic transducer design is demonstrated. The new construction method of multi-element transducers introduces 2 distinctive improvements. First, active ferroelectret material is not discretized into elements, and second, the need of structuring upper and/or lower electrodes in advance of the permanent polarization of the film is removed. The aperture discretization and the mechanical connection are achieved in one step using a through-thickness conductive tape. To validate the procedure, 2 linear array prototypes of 32 elements, with a pitch of 3.43 mm and a wide usable frequency range from 30 to 300 kHz, were built and evaluated using a commercial phased-array system. A low crosstalk among elements, below -30 dB, was measured by interferometry. Likewise, a homogeneous response of the array elements, with a maximum deviation of +/-1.8 dB, was obtained. Acoustic beam steering measurements were accomplished at different deflection angles using a calibrated microphone. The ultrasonic beam parameters, namely, lateral resolution, side lobe level, grating lobes, and focus depth, were congruent with theory. Acoustic images of a single reflector were obtained using one of the array elements as the receiver. Resulting images are also in accordance with numerical simulation, demonstrating the feasibility of using these arrays in pulse-echo mode. The proposed procedure simplifies the manufacturing of multidimensional arrays with arbitrary shape elements and not uniformly distributed. Furthermore, this concept can be extended to nonflat arrays as long as the transducer substrate conforms to a developable surface.

Method for Ultrasonic Imaging and Device for Performing the Method

NASA Technical Reports Server (NTRS)

Madaras, Eric I. (Inventor)

1997-01-01

A method for ultrasonic imaging of interior structures and flaws in a test specimen with a smooth or irregular contact surfaces, in which an ultrasonic transducer is coupled acoustically to the contact surface via a plurality of ultrasonic wave guides with equal delay times. The wave guides are thin and bendable, so they adapt to variations in the distance between the transducer and different parts of the contact surface by bending more or less. All parts of the irregular contact surface accordingly receive sound waves that are in phase, even when the contact surface is irregular, so a coherent sound wave is infused in the test specimen. The wave guides can be arranged in the form of an ultrasonic brush, with a flat head for coupling to a flat transducer, and free bristles that can be pressed against the test specimen. By bevelling the bristle ends at a suitable angle, shear mode waves can be infused into the test specimen from a longitudinal mode transducer.

Design of efficient, broadband single-element (20-80 MHz) ultrasonic transducers for medical imaging applications.

PubMed

Cannata, Jonathan M; Ritter, Timothy A; Chen, Wo-Hsing; Silverman, Ronald H; Shung, K Kirk

2003-11-01

This paper discusses the design, fabrication, and testing of sensitive broadband lithium niobate (LiNbO3) single-element ultrasonic transducers in the 20-80 MHz frequency range. Transducers of varying dimensions were built for an f# range of 2.0-3.1. The desired focal depths were achieved by either casting an acoustic lens on the transducer face or press-focusing the piezoelectric into a spherical curvature. For designs that required electrical impedance matching, a low impedance transmission line coaxial cable was used. All transducers were tested in a pulse-echo arrangement, whereby the center frequency, bandwidth, insertion loss, and focal depth were measured. Several transducers were fabricated with center frequencies in the 20-80 MHz range with the measured -6 dB bandwidths and two-way insertion loss values ranging from 57 to 74% and 9.6 to 21.3 dB, respectively. Both transducer focusing techniques proved successful in producing highly sensitive, high-frequency, single-element, ultrasonic-imaging transducers. In vivo and in vitro ultrasonic backscatter microscope (UBM) images of human eyes were obtained with the 50 MHz transducers. The high sensitivity of these devices could possibly allow for an increase in depth of penetration, higher image signal-to-noise ratio (SNR), and improved image contrast at high frequencies when compared to previously reported results.

Air-Coupled Ultrasonic Measurements in Composites

NASA Astrophysics Data System (ADS)

Kommareddy, V.; Peters, J. J.; Dayal, V.; Hsu, D. K.

2004-02-01

Air-coupled ultrasound is a non-contact technique and has clear advantages over water-coupled testing. Research of air-coupled ultrasonics, especially using capacitance and micromachined transducers, has been extensively reported in the literature. This paper reports our experience of applying piezoceramic air-coupled transducers for nondestructive evaluation of composites. The beam profiles of air-coupled piezoceramic transducers, with and without apodization, were mapped out. The transmission of air-coupled ultrasonic energy through composite plates of different thickness was measured experimentally; model calculation of the transmission coefficient, taking into account the frequency bandwidth of the transducer, agreed with the measurement results. The occurrence of diffraction phenomenon ("Poisson bright spot") while imaging flaws in composite laminates was investigated. The resolution of scanned images obtained with air-coupled transducers was investigated for different frequency, focusing, and apodization conditions.

Micromachined ultrasonic transducers for air-coupled nondestructive evaluation

NASA Astrophysics Data System (ADS)

Hansen, Sean T.; Degertekin, F. Levent; Khuri-Yakub, Butrus T.

1999-01-01

Conventional methods of ultrasonic non-destructive evaluation (NDE) use liquids to couple sound waves into the test samples. This either requires immersion of the parts to be examined or the use of complex and bulky water squirting systems that must be scanned over the structure. Air-coupled ultrasonic systems eliminate these requirements if the losses at air-solid interfaces are tolerable. Micromachined capacitive ultrasonic transducers (cMUTs) have been shown to have more than 100 dB dynamic range when used in the bistatic transmission mode. In this paper, we present results of a pitch-catch transmission system using cMUTs that achieves a 103 dB dynamic range. Each transducer consists of 10,000 silicon nitride membranes of 100 micrometers diameter connected in parallel. This geometry result in transducers with a resonant frequency around 2.3 MHz. These transducers can be used in transmission experiments at normal incident to the sample or to excite and detect guided waves in aluminum and composite plates. In this paper we present ultrasonic defect detection results from both through transmission and guided Lamb wave experiments in aluminum and composite plates, such as those used in aircraft.

Ultrasonic probe for inspecting double-wall tube

DOEpatents

Cook, Kenneth V.; Cunningham, Jr., Robert A.; Murrin, Horace T.

1983-01-01

An ultrasonic probe for inspecting the interface between the walls of a double-wall tube comprises a cylindrical body member having two cavities axially spaced apart thereon. The probe is placed in the tube and ultrasonic energy is transmitted from a transducer in its body member to a reflector in one of its cavities and thence into the inner wall of the tube. A second transducer in the probe body member communicates with the second cavity through a collimation passage in the body member, and the amount of ultrasonic energy reflected from the interface between the walls of the tube to a second reflector through the collimation passage to the second transducer depends upon the characteristics of said interface.

An Ultrasonic Compactor for Oil and Gas Exploration

NASA Astrophysics Data System (ADS)

Feeney, Andrew; Sikaneta, Sakalima; Harkness, Patrick; Lucas, Margaret

The Badger Explorer is a rig-less oil and gas exploration tool which drills into the subsea environment to collect geological data. Drill spoil is transported from the front end of the system to the rear, where the material is compacted. Motivated by the need to develop a highly efficient compaction system, an ultrasonic compactor for application with granular geological materials encountered in subsea environments is designed and fabricated as part of this study. The finite element method is used to design a compactor configuration suitable for subsea exploration, consisting of a vibrating ultrasonic horn called a resonant compactor head, which operates in a longitudinal mode at 20 kHz, driven by a Langevin piezoelectric transducer. A simplified version of the compactor is also designed, due to its ease of incorporating in a lab-based experimental rig, in order to demonstrate enhanced compaction using ultrasonics. Numerical analysis of this simplified compactor system is supported with experimental characterisation using laser Doppler vibrometry. Compaction testing is then conducted on granular geological material, showing that compaction can be enhanced through the use of an ultrasonic compactor.

Finite element analysis of hysteresis effects in piezoelectric transducers

NASA Astrophysics Data System (ADS)

Simkovics, Reinhard; Landes, Hermann; Kaltenbacher, Manfred; Hoffelner, Johann; Lerch, Reinhard

2000-06-01

The design of ultrasonic transducers for high power applications, e.g. in medical therapy or production engineering, asks for effective computer aided design tools to analyze the occurring nonlinear effects. In this paper the finite-element-boundary-element package CAPA is presented that allows to model different types of electromechanical sensors and actuators. These transducers are based on various physical coupling effects, such as piezoelectricity or magneto- mechanical interactions. Their computer modeling requires the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields as well as coupled mechanical-acoustic fields. With the reported software environment we are able to compute the dynamic behavior of electromechanical sensors and actuators by taking into account geometric nonlinearities, nonlinear wave propagation and ferroelectric as well as magnetic material nonlinearities. After a short introduction to the basic theory of the numerical calculation schemes, two practical examples will demonstrate the applicability of the numerical simulation tool. As a first example an ultrasonic thickness mode transducer consisting of a piezoceramic material used for high power ultrasound production is examined. Due to ferroelectric hysteresis, higher order harmonics can be detected in the actuators input current. Also in case of electrical and mechanical prestressing a resonance frequency shift occurs, caused by ferroelectric hysteresis and nonlinear dependencies of the material coefficients on electric field and mechanical stresses. As a second example, a power ultrasound transducer used in HIFU-therapy (high intensity focused ultrasound) is presented. Due to the compressibility and losses in the propagating fluid a nonlinear shock wave generation can be observed. For both examples a good agreement between numerical simulation and experimental data has been achieved.

Ultrasonic Leak Detection System

NASA Technical Reports Server (NTRS)

Youngquist, Robert C. (Inventor); Moerk, J. Steven (Inventor)

1998-01-01

A system for detecting ultrasonic vibrations. such as those generated by a small leak in a pressurized container. vessel. pipe. or the like. comprises an ultrasonic transducer assembly and a processing circuit for converting transducer signals into an audio frequency range signal. The audio frequency range signal can be used to drive a pair of headphones worn by an operator. A diode rectifier based mixing circuit provides a simple, inexpensive way to mix the transducer signal with a square wave signal generated by an oscillator, and thereby generate the audio frequency signal. The sensitivity of the system is greatly increased through proper selection and matching of the system components. and the use of noise rejection filters and elements. In addition, a parabolic collecting horn is preferably employed which is mounted on the transducer assembly housing. The collecting horn increases sensitivity of the system by amplifying the received signals. and provides directionality which facilitates easier location of an ultrasonic vibration source.

Broadband gradient impedance matching using an acoustic metamaterial for ultrasonic transducers

NASA Astrophysics Data System (ADS)

Li, Zheng; Yang, Dan-Qing; Liu, Shi-Lei; Yu, Si-Yuan; Lu, Ming-Hui; Zhu, Jie; Zhang, Shan-Tao; Zhu, Ming-Wei; Guo, Xia-Sheng; Wu, Hao-Dong; Wang, Xin-Long; Chen, Yan-Feng

2017-02-01

High-quality broadband ultrasound transducers yield superior imaging performance in biomedical ultrasonography. However, proper design to perfectly bridge the energy between the active piezoelectric material and the target medium over the operating spectrum is still lacking. Here, we demonstrate a new anisotropic cone-structured acoustic metamaterial matching layer that acts as an inhomogeneous material with gradient acoustic impedance along the ultrasound propagation direction. When sandwiched between the piezoelectric material unit and the target medium, the acoustic metamaterial matching layer provides a broadband window to support extraordinary transmission of ultrasound over a wide frequency range. We fabricated the matching layer by etching the peeled silica optical fibre bundles with hydrofluoric acid solution. The experimental measurement of an ultrasound transducer equipped with this acoustic metamaterial matching layer shows that the corresponding -6 dB bandwidth is able to reach over 100%. This new material fully enables new high-end piezoelectric materials in the construction of high-performance ultrasound transducers and probes, leading to considerably improved resolutions in biomedical ultrasonography and compact harmonic imaging systems.

Inspecting Composites with Airborne Ultrasound: Through Thick and Thin

NASA Astrophysics Data System (ADS)

Hsu, David K.; Barnard, Daniel J.

2006-03-01

The inspection of composite materials and structures with air-coupled ultrasound has the obvious advantage that it is non-contact, non-contaminating, and free from couplants. However, the transmission efficiency from air to solid is extremely low due to the enormous difference in acoustic impedance. The development of more efficient airborne ultrasonic transducers over the years has made it possible, and even practical, to inspect composites with airborne ultrasound. It is now possible to drive newer, more efficient transducers with a portable ultrasonic flaw detector to inspect 2-inch thick solid CFRP in air. In this paper we describe our experience in applying air-coupled ultrasound to the inspection of a variety of composite structures, from honeycomb with thin composite facesheet to very thick solid laminates. General considerations for making airborne ultrasonic measurement in composite are given, and mechanism of transmission through honeycomb core, and resonance effects in transmitting through thick laminates will be described. NDE results of defects and damage in various composite structures will be presented.

High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

PubMed Central

Chen, Yan; Lam, Kwok-Ho; Zhou, Dan; Yue, Qingwen; Yu, Yanxiong; Wu, Jinchuan; Qiu, Weibao; Sun, Lei; Zhang, Chao; Luo, Haosu; Chan, Helen L. W.; Dai, Jiyan

2014-01-01

Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33∼2000 pC/N, kt∼60%) near the morphotropic phase boundary (MPB). Ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc) and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed. PMID:25076222

Nursing Care Hour Standards Study. Part 1. Section A. Patient Classification System Model Development

DTIC Science & Technology

1981-09-01

Change = 2311 (257) Teaching - Diabetic = 2313 (258) Labor Room Examination and Preparation, Routine = 2434 (259) Fetal Heart Tones, Manual = 2412 (260... Fetal Heart Tones, Doppler = 2413 (261) Dilatation and Effecement Assessment = 2403 (262) Dilatation and Effacement Assessment, Assisting Physician...Ultrasonic Transducer/Tocotransducer = 2435 (270) Monitoring Fetal Heart Tones, Ultrasonic Transducer = 2436 (271) Monitoring Fetal Heart Tones, Ultrasonic

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration

PubMed Central

Wei, Xiaoyuan; Yang, Yuan; Yao, Wenqing; Zhang, Lei

2017-01-01

Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on. PMID:28973996

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration.

PubMed

Wei, Xiaoyuan; Yang, Yuan; Yao, Wenqing; Zhang, Lei

2017-09-30

Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

Criteria for the selection of focusing ultrasonic probes

NASA Technical Reports Server (NTRS)

Schlengermann, U.

1978-01-01

The principles of operation employed in the focusing of a sound field are considered, taking into account the use of solid and liquid coupling media. The focusing limits for a given transducer are investigated. As a diffraction phenomenon, focusing is a function of the system dimensions, the frequency, and the sound velocity. The frequency and the material used for the lenses are in most cases determined in accordance with considerations regarding sound propagation. Changes in the focus are therefore effected mainly by the selection of transducer and lens dimensions. The functions of the focusing factor for a normal immersion probe and a direct contact angle probe are represented in graphs. The deviation of the appropriate parametric values for an ultrasonic probe is illustrated with the aid of examples.

Ultrasonic unipolar pulse/echo instrument

DOEpatents

Hughes, M.J.; Hsu, D.K.; Thompson, D.O.; Wormley, S.J.

1993-04-06

An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

Ultrasonic unipolar pulse/echo instrument

DOEpatents

Hughes, Michael S.; Hsu, David K.; Thompson, Donald O.; Wormley, Samuel J.

1993-01-01

An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

Non-bonded ultrasonic transducer

DOEpatents

Eoff, J.M.

1984-07-06

A mechanically assembled non-bonded ultrasonic transducer includes a substrate, a piezoelectric film, a wetting agent, a thin metal electrode, and a lens held in intimate contact by a mechanical clamp. No epoxy or glue is used in the assembly of this device.

Ultrasonic inspection of rocket fuel model using laminated transducer and multi-channel step pulser

NASA Astrophysics Data System (ADS)

Mihara, T.; Hamajima, T.; Tashiro, H.; Sato, A.

2013-01-01

For the ultrasonic inspection for the packing of solid fuel in a rocket booster, an industrial inspection is difficult. Because the signal to noise ratio in ultrasonic inspection of rocket fuel become worse due to the large attenuation even using lower frequency ultrasound. For the improvement of this problem, we tried to applied the two techniques in ultrasonic inspection, one was the step function pulser system with the super wideband frequency properties and the other was the laminated element transducer. By combining these two techniques, we developed the new ultrasonic measurement system and demonstrated the advantages in ultrasonic inspection of rocket fuel model specimen.

Method and apparatus to characterize ultrasonically reflective contrast agents

NASA Technical Reports Server (NTRS)

Pretlow, Robert A., III (Inventor)

1993-01-01

A method and apparatus for characterizing the time and frequency response of an ultrasonically reflective contrast agent is disclosed. An ultrasonically reflective contrast agent is injected, under constant pressure, into a fluid flowing through a pump flow circuit. The fluid and the ultrasonically reflective contrast agent are uniformly mixed in a mixing chamber, and the uniform mixture is passed through a contrast agent chamber. The contrast agent chamber is acoustically and axially interposed between an ultrasonic transducer chamber and an acoustic isolation chamber. A pulse of ultrasonic energy is transmitted into the contrast agent chamber from the ultrasonic transducer chamber. An echo waveform is received from the ultrasonically reflective contrast agent, and it is analyzed to determine the time and frequency response of the ultrasonically reflective contrast agent.

Digital ultrasonic signal processing: Primary ultrasonics task and transducer characterization use and detailed description

NASA Technical Reports Server (NTRS)

Hammond, P. L.

1979-01-01

This manual describes the use of the primary ultrasonics task (PUT) and the transducer characterization system (XC) for the collection, processing, and recording of data received from a pulse-echo ultrasonic system. Both PUT and XC include five primary functions common to many real-time data acquisition systems. Some of these functions are implemented using the same code in both systems. The solicitation and acceptance of operator control input is emphasized. Those operations not under user control are explained.

Autoresonant control of nonlinear mode in ultrasonic transducer for machining applications.

PubMed

Babitsky, V I; Astashev, V K; Kalashnikov, A N

2004-04-01

Experiments conducted in several countries have shown that the improvement of machining quality can be promoted through conversion of the cutting process into one involving controllable high-frequency vibration at the cutting zone. This is achieved through the generation and maintenance of ultrasonic vibration of the cutting tool to alter the fracture process of work-piece material cutting to one in which loading of the materials at the tool tip is incremental, repetitive and controlled. It was shown that excitation of the high-frequency vibro-impact mode of the tool-workpiece interaction is the most effective way of ultrasonic influence on the dynamic characteristics of machining. The exploitation of this nonlinear mode needs a new method of adaptive control for excitation and stabilisation of ultrasonic vibration known as autoresonance. An approach has been developed to design an autoresonant ultrasonic cutting unit as an oscillating system with an intelligent electronic feedback controlling self-excitation in the entire mechatronic system. The feedback produces the exciting force by means of transformation and amplification of the motion signal. This allows realisation for robust control of fine resonant tuning to bring the nonlinear high Q-factor systems into technological application. The autoresonant control provides the possibility of self-tuning and self-adaptation mechanisms for the system to keep the nonlinear resonant mode of oscillation under unpredictable variation of load, structure and parameters. This allows simple regulation of intensity of the process whilst keeping maximum efficiency at all times. An autoresonant system with supervisory computer control was developed, tested and used for the control of the piezoelectric transducer during ultrasonically assisted cutting. The system has been developed as combined analog-digital, where analog devices process the control signal, and parameters of the devices are controlled digitally by computer. The system was applied for advanced machining of aviation materials.

One-sided ultrasonic determination of third order elastic constants using angle-beam acoustoelasticity measurements

NASA Astrophysics Data System (ADS)

Muir, Dave D.

This thesis describes procedures and theory for a family of one-sided ultrasonic methods for determining third order elastic constants (TOEC) using sets of angle-beam wedges mounted on one side of a specimen. The methods are based on the well-known acoustoelastic effect, which is the change of wave speed with applied loads and is a consequence of the mechanical nonlinearity of a material. Increases in material nonlinearity have been correlated to the progression of damage, indicating that tracking changes in TOECs may provide a practical means of monitoring damage accumulation at the microstructural level prior to formation of macroscopic defects. Ultrasonic methods are one of the only ways to measure TOECs, and most prior techniques have utilized wave propagation paths parallel and perpendicular to the loading directions. A few additional ultrasonic techniques reported in the literature have employed oblique paths but with immersion coupling. These reported techniques are generally unsuitable for field implementation. The one-sided contact approach described here is applicable for in situ measurements of TOECs and thus lays the foundation for tracking of TOECs with damage. Theory is reviewed and further developed for calculating predicted velocity changes, and thus time shifts, as a function of uniaxial tensile loading for longitudinal, shear vertical, and shear horizontal waves in the context of angle-beam transducers mounted on the surface of the specimen. A comparison is made to published results where possible. The inverse problem of determining the three TOECs of an isotropic material from three measurements employing three different angle beam configurations is comprehensively analyzed. Four configurations providing well-posed solutions are identified and examined. A detailed sensitivity analysis is carried out to identify the best mounting configuration, wave mode combinations, refracted angles and geometry requirements for recovering the three TOECs. Two transducer mounting configurations are considered: (1) attached (glued-on) transducers potentially suitable for in situ monitoring, and (2) floating (oil-coupled) transducers potentially suitable for single measurements. Limited experimental results are presented for the attached case using two longitudinal measurements and one shear vertical measurement. The floating case experiments utilized three of the four well-posed solutions, and measurements were made on several aluminum alloys and low carbon steel. Key experimental issues are identified and discussed for both transducer mounting configurations. The specific contributions of this thesis are: (1) Development of the general theory for determining TOECs of isotropic materials with a one-sided approach using contact angle-beam transducers. This development includes identification of four valid measurement configurations that result in a well-posed problem for recovering the three TOECs. (2) Development of the specific theory as applied to attached (i.e., glued-on) angle-beam transducers that have a variable separation distance with load. This coupling method is potentially suitable for in situ monitoring applications. (3) Development of the specific theory as applied to floating (i.e., liquid-coupled) angle-beam transducers where the separation distance does not change with load. This method is potentially suitable for single field or laboratory measurements. (4) Comparison of the eight valid TOEC recovery methods (four wave mode configurations, each having two mounting techniques) via numerical simulations and a detailed sensitivity analysis in which the effect of all expected measurement and parameter errors on determination of the TOECs is quantified. (5) Development of experimental methods that provide insight as to the relative merits of the attached vs. floating coupling methods.

Ultrasonic probe for inspecting double-wall tube. [Patent application

DOEpatents

Cook, K.V.; Cunningham, R.A. Jr.; Murrin, H.T.

1981-05-29

An ultrasonic probe for inspecting the interface between the walls of a double-wall tube comprises a cylindrical body member having two cavities axially spaced apart thereon. The probe is placed in the tube and ultrasonic energy is transmitted from a transducer in its body member to a reflector in one of its cavities and thence into the inner wall of the tube. A second transducer in the probe body member communicates with the second cavity through a collimation passage in the body member, and the amount of ultrasonic energy reflected from the interface between the walls of the tube to a second reflector through the collimation passage to the second transducer depends upon the characteristics of said interface.

Opto-acoustic transducer for medical applications

DOEpatents

Benett, William; Celliers, Peter; Da Silva, Luiz; Glinsky, Michael; London, Richard; Maitland, Duncan; Matthews, Dennis; Krulevich, Peter; Lee, Abraham

2002-01-01

This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control.

Opto-acoustic transducer for medical applications

DOEpatents

Benett, William; Celliers, Peter; Da Silva, Luiz; Glinsky, Michael; London, Richard; Maitland, Duncan; Matthews, Dennis; Krulevich, Peter; Lee, Abraham

1999-01-01

This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control.

Opto-acoustic transducer for medical applications

DOEpatents

Benett, W.; Celliers, P.; Da Silva, L.; Glinsky, M.; London, R.; Maitland, D.; Matthews, D.; Krulevich, P.; Lee, A.

1999-08-31

This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control. 7 figs.

Non-bonded piezoelectric ultrasonic transducer

DOEpatents

Eoff, James M.

1985-01-01

A mechanically assembled non-bonded ultrasonic transducer includes a substrate, a piezoelectric film, a wetting agent, a thin metal electrode, and a lens held in intimate contact by a mechanical clamp. No epoxy or glue is used in the assembly of this device.

Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1995-01-01

In this Progress Report, the author describes the continuing research to explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize complex materials. Images obtained using an unmodified medical ultrasonic imaging system of a bonded aluminum plate sample with a simulated disbond region are presented. The disbond region was produced by adhering a piece of plain white paper to a piece of cellophane tape and applying the paper-tape combination to one of the aluminum plates. Because the area under the paper was not adhesively bonded to the aluminum plate, this arrangement more closely simulates a disbond. Images are also presented for an aluminum plate sample with an epoxy strip adhered to one side to help provide information for the interpretation of the images of the bonded aluminum plate sample containing the disbond region. These images are compared with corresponding conventional ultrasonic contact transducer measurements in order to provide information regarding the nature of the disbonded region. The results of this on-going investigation may provide a step toward the development of a rapid, real-time, and portable method of ultrasonic inspection and characterization based on linear array technology. In Section 2 of this Progress Report, the preparation of the aluminum plate specimens is described. Section 3 describes the method of linear array imaging. Sections 4 and 5 present the linear array images and results from contact transducer measurements, respectively. A discussion of the results are presented in Section 6.

Calculation of acoustic field based on laser-measured vibration velocities on ultrasonic transducer surface

NASA Astrophysics Data System (ADS)

Hu, Liang; Zhao, Nannan; Gao, Zhijian; Mao, Kai; Chen, Wenyu; Fu, Xin

2018-05-01

Determination of the distribution of a generated acoustic field is valuable for studying ultrasonic transducers, including providing the guidance for transducer design and the basis for analyzing their performance, etc. A method calculating the acoustic field based on laser-measured vibration velocities on the ultrasonic transducer surface is proposed in this paper. Without knowing the inner structure of the transducer, the acoustic field outside it can be calculated by solving the governing partial differential equation (PDE) of the field based on the specified boundary conditions (BCs). In our study, the BC on the transducer surface, i.e. the distribution of the vibration velocity on the surface, is accurately determined by laser scanning measurement of discrete points and follows a data fitting computation. In addition, to ensure the calculation accuracy for the whole field even in an inhomogeneous medium, a finite element method is used to solve the governing PDE based on the mixed BCs, including the discretely measured velocity data and other specified BCs. The method is firstly validated on numerical piezoelectric transducer models. The acoustic pressure distributions generated by a transducer operating in an homogeneous and inhomogeneous medium, respectively, are both calculated by the proposed method and compared with the results from other existing methods. Then, the method is further experimentally validated with two actual ultrasonic transducers used for flow measurement in our lab. The amplitude change of the output voltage signal from the receiver transducer due to changing the relative position of the two transducers is calculated by the proposed method and compared with the experimental data. This method can also provide the basis for complex multi-physical coupling computations where the effect of the acoustic field should be taken into account.

Sub-micron elastic property characterization of materials using a near-field scanning optical microscope

NASA Astrophysics Data System (ADS)

Blodgett, David W.; Spicer, James B.

2001-12-01

The ability to characterize the sub-surface mechanical properties of a bulk or thin film material at the sub-micron level has applications in the microelectronics and thin film industries. In the microelectronics industry, with the decrease of line widths and the increase of component densities, sub-surface voids have become increasingly detrimental. Any voids along an integrated circuit (IC) line can lead to improper electrical connections between components and can cause failure of the device. In the thin film industry, the detection of impurities is also important. Any impurities can detract from the film's desired optical, electrical, or mechanical properties. Just as important as the detection of voids and impurities, is the measurement of the elastic properties of a material on the nanometer scale. These elastic measurements provide insight into the microstructural properties of the material. We have been investigating a technique that couples the high-resolution surface imaging capabilities of the apertureless near-field scanning optical microscope (ANSOM) with the sub-surface characterization strengths of high-frequency ultrasound. As an ultrasonic wave propagates, the amplitude decreases due to geometrical spreading, attenuation from absorption, and scattering from discontinuities. Measurement of wave speeds and attenuation provides the information needed to quantify the bulk or surface properties of a material. The arrival of an ultrasonic wave at or along the surface of a material is accompanied with a small surface displacement. Conventional methods for the ultrasound detection rely on either a contact transducer or optical technique (interferometric, beam deflection, etc.). However, each of these methods is limited by the spatial resolution dictated by the detection footprint. As the footprint size increases, variations across the ultrasonic wavefront are effectively averaged, masking the presence of any nanometer-scale sub-surface or surface mechanical property variations. The use of an ANSOM for sensing ultrasonic wave arrivals reduces the detection footprint allowing any nanometer scale variations in the microstructure of a material to be detected. In an ANSOM, the ultrasonic displacement is manifested as perturbations on the near-field signal due to the small variations in the tip-sample caused by the wave arrival. Due to the linear dependence of the near-field signal on tip-sample separation, these perturbations can be interpreted using methods identical to those for conventional ultrasonic techniques. In this paper, we report results using both contact transducer (5 MHz) and laser-generated ultrasound.

Air-coupled ultrasound: a novel technique for monitoring the curing of thermosetting matrices.

PubMed

Lionetto, Francesca; Tarzia, Antonella; Maffezzoli, Alfonso

2007-07-01

A custom-made, air-coupled ultrasonic device was applied to cure monitoring of thick samples (7-10 mm) of unsaturated polyester resin at room temperature. A key point was the optimization of the experimental setup in order to propagate compression waves during the overall curing reaction by suitable placement of the noncontact transducers, placed on the same side of the test material, in the so-called pitch-catch configuration. The progress of polymerization was monitored through the variation of the time of flight of the propagating longitudinal waves. The exothermic character of the polymerization was taken into account by correcting the measured value of time of flight with that one in air, obtained by sampling the air velocity during the experiment. The air-coupled ultrasonic results were compared with those obtained from conventional contact ultrasonic measurements. The good agreement between the air-coupled ultrasonic results and those obtained by the rheological analysis demonstrated the reliability of air-coupled ultrasound in monitoring the changes of viscoelastic properties at gelation and vitrification. The position of the transducers on the same side of the sample makes this technique suitable for on-line cure monitoring during several composite manufacturing technologies.

Distributed temperature sensors development using an stepped-helical ultrasonic waveguide

NASA Astrophysics Data System (ADS)

Periyannan, Suresh; Rajagopal, Prabhu; Balasubramaniam, Krishnan

2018-04-01

This paper presents the design and development of the distributed ultrasonic waveguide temperature sensors using some stepped-helical structures. Distributed sensing has several applications in various industries (oil, glass, steel) for measurement of physical parameters such as level, temperature, viscosity, etc. This waveguide incorporates a special notch or bend for obtaining ultrasonic wave reflections from the desired locations (Gage-lengths) where local measurements are desired. In this paper, a multi-location measurement wave-guide, with a measurement capability of 18 locations in a single wire, has been fabricated. The distribution of these sensors is both in the axial as well as radial directions using a stepped-helical spring configuration. Also, different high temperature materials have been chosen for the wave-guide. Both lower order axi-symmetric guided ultrasonic modes (L(0,1) and T(0,1)) were employed. These wave modes were generated/received (pulse-echo approach) using conventional longitudinal and shear transducers, respectively. Also, both the wave modes were simultaneously generated/received and compared using shear transducer for developing the distributed helical wave-guide sensors. The effect of dispersion of the wave modes due to curvature effects will also be discussed.

Ejection of small droplet from microplate using focused ultrasound

NASA Astrophysics Data System (ADS)

Tanaka, Hiroki; Mizuno, Yosuke; Nakamura, Kentaro

2017-08-01

We discussed an ultrasonic system for single-droplet ejection from a microplate, which is one of the basic and important procedures in the noncontact handling of droplets in air. In this system, a 1.5 MHz concave transducer located below the microplate is used for chasing the liquid surface through a pulse echo method, and also for the ejection of a 1 µL single droplet by the burst of focused ultrasound. We investigated the relationship between the droplet ejection characteristics, the distance from the transducer to the surface of liquid, the material property, and the excitation condition of the focused ultrasonic transducer. It was verified that the optimal position of the transducer was off the focal point of sound pressure by ±1 mm, because the sound intensity had to be controlled to eject a single droplet. Subsequently, we confirmed experimentally that the ejected droplet volume linearly depended on the surface tension of the liquid, and that the droplet volume and ejection velocity were determined by the Webber number, Reynolds number, and Ohnesolge number. In addition, by optimizing the duration of the burst ultrasound, the droplet volume and ejection velocity were controlled.

Renormalization Analysis of a Composite Ultrasonic Transducer with a Fractal Architecture

NASA Astrophysics Data System (ADS)

Algehyne, Ebrahem A.; Mulholland, Anthony J.

To ensure the safe operation of many safety critical structures such as nuclear plants, aircraft and oil pipelines, non-destructive imaging is employed using piezoelectric ultrasonic transducers. These sensors typically operate at a single frequency due to the restrictions imposed on their resonant behavior by the use of a single length scale in the design. To allow these transducers to transmit and receive more complex signals it would seem logical to use a range of length scales in the design so that a wide range of resonating frequencies will result. In this paper, we derive a mathematical model to predict the dynamics of an ultrasound transducer that achieves this range of length scales by adopting a fractal architecture. In fact, the device is modeled as a graph where the nodes represent segments of the piezoelectric and polymer materials. The electrical and mechanical fields that are contained within this graph are then expressed in terms of a finite element basis. The structure of the resulting discretized equations yields to a renormalization methodology which is used to derive expressions for the non-dimensionalized electrical impedance and the transmission and reception sensitivities. A comparison with a standard design shows some benefits of these fractal designs.

Micromachined ultrasonic transducers: 11.4 MHz transmission in air and more

NASA Astrophysics Data System (ADS)

Ladabaum, Igal; Khuri-Yakub, B. T.; Spoliansky, Dimitri

1996-01-01

The fabrication and modeling of novel, capacitive, ultrasonic air transducers is reported. Transmission experiments in air at 11.4, 9.2, and 3.1 MHz are shown to correspond with theory. The transducers are made using surface micromachining techniques, which enable the realization of center frequencies ranging from 1.8 to 11.6 MHz. The bandwidth of the transducers ranges from 5% to 20%, depending on processing parameters. Custom circuitry is able to detect 10 MHz capacitance fluctuations as small as 10-18 F, which correspond to displacements on the order of 10-3 Å, in a bandwidth of 2 MHz with a signal to noise ratio of 20 dB. Such detection sensitivity is shown to yield air transducer systems capable of withstanding over 100 dB of signal attenuation, a figure of merit that has significant implications for ultrasonic imaging, nondestructive evaluation, gas flow and composition measurements, and range sensing.

Characteristics of Ultrasonic Linear Motor that Incorporates Two Transducers at an Acute Angle

NASA Astrophysics Data System (ADS)

Suzuki, Atsuyuki; Tsunoji, Masaki; Tsujino, Jiromaru

2013-07-01

In this study, we have developed an ultrasonic linear motor that incorporates two transducers at an acute angle. The two transducers are used to generate the vertical and horizontal vibration components. The complex vibration is excited using two electrical sources with a phase shift. Ultrasonic motors have unique characteristics such as silent motion and absence of magnetic noise. These characteristics are suitable for use in hospitals and so on. Therefore, we focus on developing actuators for use in a medical bed, specifically a bedsore prevention bed. A study of the vibration characteristics of the motor showed that the resonant frequencies of the transducers were appropriate, although the vibration amplitude of one transducer was less than that of the other. A study of the load characteristics showed that a no-load speed of 267 mm/s and a maximum thrust of 40 N were obtained.

Ultrahigh Frequency Lensless Ultrasonic Transducers for Acoustic Tweezers Application

PubMed Central

Hsu, Hsiu-Sheng; Li, Ying; Lee, Changyang; Lin, Anderson; Zhou, Qifa; Kim, Eun Sok; Shung, Kirk Koping

2014-01-01

Similar to optical tweezers, a tightly focused ultrasound microbeam is needed to manipulate microparticles in acoustic tweezers. The development of highly sensitive ultrahigh frequency ultrasonic transducers is crucial for trapping particles or cells with a size of a few microns. As an extra lens would cause excessive attenuation at ultrahigh frequencies, two types of 200-MHz lensless transducer design were developed as an ultrasound microbeam device for acoustic tweezers application. Lithium niobate single crystal press-focused (PF) transducer and zinc oxide self-focused transducer were designed, fabricated and characterized. Tightly focused acoustic beams produced by these transducers were shown to be capable of manipulating single microspheres as small as 5 μm two-dimensionally within a range of hundreds of micrometers in distilled water. The size of the trapped microspheres is the smallest ever reported in the literature of acoustic PF devices. These results suggest that these lensless ultrahigh frequency ultrasonic transducers are capable of manipulating particles at the cellular level and that acoustic tweezers may be a useful tool to manipulate a single cell or molecule for a wide range of biomedical applications. PMID:23042219

Field deployable processing methods for stay-in-place ultrasonic transducers

NASA Astrophysics Data System (ADS)

Malarich, Nathan; Lissenden, Cliff J.; Tittmann, Bernhard R.

2018-04-01

Condition monitoring provides key data for managing the operation and maintenance of mechanical equipment in the power generation, chemical processing, and manufacturing industries. Ultrasonic transducers provide active monitoring capabilities by wall thickness measurements, elastic property determination, crack detection, and other means. In many cases the components operate in harsh environments that may include high temperature, radiation, and hazardous chemicals. Thus, it is desirable to have permanently affixed ultrasonic transducers for condition monitoring in harsh environments. Spray-on transducers provide direct coupling between the active element and the substrate, and can be applied to curved surfaces. We describe a deposition methodology for ultrasonic transducers that can be applied in the field. First, piezoceramic powders mixed into a sol-gel are air-spray deposited onto the substrate. Powder constituents are selected based on the service environment in which the condition monitoring will be performed. Then the deposited coating is pyrolyzed and partially densified using an induction heating system with a custom work coil designed to match the substrate geometry. The next step, applying the electrodes, is more challenging than might be expected because of the porosity of the piezoelectric coating and the potential reactivity of elements in the adjacent layers. After connecting lead wires to the electrodes the transducer is poled and a protective coating can be applied prior to use. Processing of a PZT-bismuth titanate transducer on a large steel substrate is described along with alternate methods.

Physics of direct-contact ultrasonic cloth drying process

DOE PAGES

Peng, Chang; Ravi, Saitej; Patel, Viral K.; ...

2017-02-27

Existing methods of drying fabrics involve energy-intensive thermal evaporation of moisture from clothes. Drying fabrics using high-frequency vibrations of piezoelectric transducers can substantially reduce drying time and energy consumption. In this method, vibrational energy generates instability on the liquid-air interface and mechanically ejects water from a wet fabric. For the first time, the physics of the ultrasonic fabric drying process in direct-contact mode is studied. The kinematic and thermal responses of water droplets and fabrics on piezoelectric crystal transducers and metal mesh–based transducers are studied. The results suggest that on piezoelectric crystal transducers, the response of a droplet subjected tomore » ultrasonic excitation is dictated by the relative magnitude of the surface tension and the ultrasonic excitation forces. The drying process for a fabric on the studied transducers consists of two regimes—vibrational and thermal. When the water content is high, the vibrational forces can eject bulk water rapidly. But the more strongly bound water within the smaller fabric pores evaporates by the thermal energy generated as a result of the viscous losses. Our study finds that a metal mesh–based transducer is more suitable for dewatering fabrics, as it facilitates the ejection of water from the fabric–transducer interface to the opposite side of the mesh. A demonstration unit developed consumes 10–20% of the water latent heat energy at water contents greater than 20%.« less

Energetic balance in an ultrasonic reactor using focused or flat high frequency transducers.

PubMed

Hallez, L; Touyeras, F; Hihn, J Y; Klima, J

2007-09-01

In order to undertake irradiation of polymer blocks or films by ultrasound, this paper deals with the measurements of ultrasonic power and its distribution within the cell by several methods. The electric power measured at the transducer input is compared to the ultrasonic power input to the cell evaluated by calorimetry and radiation force measurement for different generator settings. Results obtained in the specific case of new transducer types (composites and focused composites i.e., HIFU: high intensity focused ultrasound) provide an opportunity to conduct a discussion about measurement methods. It has thus been confirmed that these measurement techniques can be applied to HIFU transducers. For all cases, results underlined the fact that measurement of radiation pressure for power evaluation is more adapted to low powers (<15 W) and that measurement by calorimetry is a valid technique for global energy measurements. Composites and monocomponent transducers were compared and it appears that the presence of an adaptation glass plate reduces the efficiency of the monocomponent transducers. The distribution of ultrasonic intensity is qualitatively depicted by sono-chemiluminescence of luminol. Finally, the quantity of energy absorbed by samples placed in the sound field is determined and the temperature distribution monitored as a function of wall distance. This energetic balance allows us to understand the global behaviour of all experimental set-ups made up of a generator-transducer-liquid and sample.

Physics of direct-contact ultrasonic cloth drying process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Chang; Ravi, Saitej; Patel, Viral K.

Existing methods of drying fabrics involve energy-intensive thermal evaporation of moisture from clothes. Drying fabrics using high-frequency vibrations of piezoelectric transducers can substantially reduce drying time and energy consumption. In this method, vibrational energy generates instability on the liquid-air interface and mechanically ejects water from a wet fabric. For the first time, the physics of the ultrasonic fabric drying process in direct-contact mode is studied. The kinematic and thermal responses of water droplets and fabrics on piezoelectric crystal transducers and metal mesh–based transducers are studied. The results suggest that on piezoelectric crystal transducers, the response of a droplet subjected tomore » ultrasonic excitation is dictated by the relative magnitude of the surface tension and the ultrasonic excitation forces. The drying process for a fabric on the studied transducers consists of two regimes—vibrational and thermal. When the water content is high, the vibrational forces can eject bulk water rapidly. But the more strongly bound water within the smaller fabric pores evaporates by the thermal energy generated as a result of the viscous losses. Our study finds that a metal mesh–based transducer is more suitable for dewatering fabrics, as it facilitates the ejection of water from the fabric–transducer interface to the opposite side of the mesh. A demonstration unit developed consumes 10–20% of the water latent heat energy at water contents greater than 20%.« less

Non-contact thickness measurement using UTG

NASA Technical Reports Server (NTRS)

Bui, Hoa T. (Inventor)

1996-01-01

A measurement structure for determining the thickness of a specimen without mechanical contact but instead employing ultrasonic waves including an ultrasonic transducer and an ultrasonic delay line connected to the transducer by a retainer or collar. The specimen, whose thickness is to be measured, is positioned below the delay line. On the upper surface of the specimen a medium such as a drop of water is disposed which functions to couple the ultrasonic waves from the delay line to the specimen. A receiver device, which may be an ultrasonic thickness gauge, receives reflected ultrasonic waves reflected from the upper and lower surface of the specimen and determines the thickness of the specimen based on the time spacing of the reflected waves.

An adjustable multi-scale single beam acoustic tweezers based on ultrahigh frequency ultrasonic transducer.

PubMed

Chen, Xiaoyang; Lam, Kwok Ho; Chen, Ruimin; Chen, Zeyu; Yu, Ping; Chen, Zhongping; Shung, K Kirk; Zhou, Qifa

2017-11-01

This paper reports the fabrication, characterization, and microparticle manipulation capability of an adjustable multi-scale single beam acoustic tweezers (SBAT) that is capable of flexibly changing the size of "tweezers" like ordinary metal tweezers with a single-element ultrahigh frequency (UHF) ultrasonic transducer. The measured resonant frequency of the developed transducer at 526 MHz is the highest frequency of piezoelectric single crystal based ultrasonic transducers ever reported. This focused UHF ultrasonic transducer exhibits a wide bandwidth (95.5% at -10 dB) due to high attenuation of high-frequency ultrasound wave, which allows the SBAT effectively excite with a wide range of excitation frequency from 150 to 400 MHz by using the "piezoelectric actuator" model. Through controlling the excitation frequency, the wavelength of ultrasound emitted from the SBAT can be changed to selectively manipulate a single microparticle of different sizes (3-100 μm) by using only one transducer. This concept of flexibly changing "tweezers" size is firstly introduced into the study of SBAT. At the same time, it was found that this incident ultrasound wavelength play an important role in lateral trapping and manipulation for microparticle of different sizes. Biotechnol. Bioeng. 2017;114: 2637-2647. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Non-contact feature detection using ultrasonic Lamb waves

DOEpatents

Sinha, Dipen N [Los Alamos, NM

2011-06-28

Apparatus and method for non-contact ultrasonic detection of features on or within the walls of hollow pipes are described. An air-coupled, high-power ultrasonic transducer for generating guided waves in the pipe wall, and a high-sensitivity, air-coupled transducer for detecting these waves, are disposed at a distance apart and at chosen angle with respect to the surface of the pipe, either inside of or outside of the pipe. Measurements may be made in reflection or transmission modes depending on the relative position of the transducers and the pipe. Data are taken by sweeping the frequency of the incident ultrasonic waves, using a tracking narrow-band filter to reduce detected noise, and transforming the frequency domain data into the time domain using fast Fourier transformation, if required.

Guided ultrasonic wave beam skew in silicon wafers

NASA Astrophysics Data System (ADS)

Pizzolato, Marco; Masserey, Bernard; Robyr, Jean-Luc; Fromme, Paul

2018-04-01

In the photovoltaic industry, monocrystalline silicon wafers are employed for solar cells with high conversion efficiency. Micro-cracks induced by the cutting process in the thin wafers can lead to brittle wafer fracture. Guided ultrasonic waves would offer an efficient methodology for the in-process non-destructive testing of wafers to assess micro-crack density. The material anisotropy of the monocrystalline silicon leads to variations of the guided wave characteristics, depending on the propagation direction relative to the crystal orientation. Selective guided ultrasonic wave excitation was achieved using a contact piezoelectric transducer with custom-made wedges for the A0 and S0 Lamb wave modes and a transducer holder to achieve controlled contact pressure and orientation. The out-of-plane component of the guided wave propagation was measured using a non-contact laser interferometer. The phase slowness (velocity) of the two fundamental Lamb wave modes was measured experimentally for varying propagation directions relative to the crystal orientation and found to match theoretical predictions. Significant wave beam skew was observed experimentally, especially for the S0 mode, and investigated from 3D finite element simulations. Good agreement was found with the theoretical predictions based on nominal material properties of the silicon wafer. The important contribution of guided wave beam skewing effects for the non-destructive testing of silicon wafers was demonstrated.

Transducer Modules for Dry-Coupled Ultrasonic Inspection of Aircraft Structures

NASA Astrophysics Data System (ADS)

Komsky, Igor N.

2004-02-01

Several types of transducer modules have been developed at Northwestern University to overcome the problems that are associated with the application of liquid or gel couplants. The modules deploy polymer films to transmit the ultrasound through a dry interface. These films are very flexible, so even with a low pressure they can be adapted to the irregular inspection surfaces. The dry-coupled transducer modules may be used for transmission and reception of both longitudinal and transverse ultrasonic waves in the MHz frequency range. The prototype modules have been integrated with the portable ultrasonic inspection units and tested on a number of aircraft structures.

Ultrasonic anechoic chamber qualification: accounting for atmospheric absorption and transducer directivity.

PubMed

Jenny, Trevor; Anderson, Brian E

2011-08-01

Qualifying an anechoic chamber for frequencies that extend into the ultrasonic range is necessary for research work involving airborne ultrasonic sound. The ANSI S12.55/ISO 3745 standard which covers anechoic chamber qualification does not extend into the ultrasonic frequency range, nor have issues pertinent to this frequency range been fully discussed in the literature. An increasing number of technologies employ ultrasound; hence the need for an ultrasonic anechoic chamber. This paper will specifically discuss the need to account for atmospheric absorption and issues pertaining to source transducer directivity by presenting some results for qualification of a chamber at Brigham Young University.

Broadband Ultrasonic Transducers

NASA Technical Reports Server (NTRS)

Heyser, R. C.

1986-01-01

New geometry spreads out resonance region of piezoelectric crystal. In new transducer, crystal surfaces made nonparallel. One surface planar; other, concave. Geometry designed to produce nearly uniform response over a predetermined band of frequencies and to attenuate strongly frequencies outside band. Greater bandwidth improves accuracy of sonar and ultrasonic imaging equipment.

Ultrasonic imaging of material flaws exploiting multipath information

NASA Astrophysics Data System (ADS)

Shen, Xizhong; Zhang, Yimin D.; Demirli, Ramazan; Amin, Moeness G.

2011-05-01

In this paper, we consider ultrasonic imaging for the visualization of flaws in a material. Ultrasonic imaging is a powerful nondestructive testing (NDT) tool which assesses material conditions via the detection, localization, and classification of flaws inside a structure. Multipath exploitations provide extended virtual array apertures and, in turn, enhance imaging capability beyond the limitation of traditional multisensor approaches. We utilize reflections of ultrasonic signals which occur when encountering different media and interior discontinuities. The waveforms observed at the physical as well as virtual sensors yield additional measurements corresponding to different aspect angles. Exploitation of multipath information addresses unique issues observed in ultrasonic imaging. (1) Utilization of physical and virtual sensors significantly extends the array aperture for image enhancement. (2) Multipath signals extend the angle of view of the narrow beamwidth of the ultrasound transducers, allowing improved visibility and array design flexibility. (3) Ultrasonic signals experience difficulty in penetrating a flaw, thus the aspect angle of the observation is limited unless access to other sides is available. The significant extension of the aperture makes it possible to yield flaw observation from multiple aspect angles. We show that data fusion of physical and virtual sensor data significantly improves the detection and localization performance. The effectiveness of the proposed multipath exploitation approach is demonstrated through experimental studies.

Simulation study of a chaotic cavity transducer based virtual phased array used for focusing in the bulk of a solid material.

PubMed

Delrue, Steven; Van Den Abeele, Koen; Bou Matar, Olivier

2016-04-01

In acoustic and ultrasonic non-destructive testing techniques, it is sometimes beneficial to concentrate sound energy at a chosen location in space and at a specific instance in time, for example to improve the signal-to-noise ratio or activate the nonlinearity of damage features. Time Reversal (TR) techniques, taking advantage of the reversible character of the wave equation, are particularly suited to focus ultrasonic waves in time and space. The characteristics of the energy focusing in solid media using principles of time reversed acoustics are highly influenced by the nature and dimensions of the medium, the number of transducers and the length of the received signals. Usually, a large number of transducers enclosing the domain of interest is needed to improve the quality of the focusing. However, in the case of highly reverberant media, the number of transducers can be reduced to only one (single-channel TR). For focusing in a non-reverberant medium, which is impossible when using only one source, an adaptation of the single-channel reciprocal TR procedure has been recently suggested by means of a Chaotic Cavity Transducer (CCT), a single element transducer glued on a cavity of chaotic shape. In this paper, a CCT is used to focus elastic energy, at different times, in different points along a predefined line on the upper surface of a thick solid sample. Doing so, all focusing points can act as a virtual phased array transducer, allowing to focus in any point along the depth direction of the sample. This is impossible using conventional reciprocal TR, as you need to have access to all points in the bulk of the material for detecting signals to be used in the TR process. To asses and provide a better understanding of this concept, a numerical study has been developed, allowing to verify the basic concepts of the virtual phased array and to illustrate multi-component time reversal focusing in the bulk of a solid material. Copyright © 2016 Elsevier B.V. All rights reserved.

Advanced ultrasonic measurement methodology for non-invasive interrogation and identification of fluids in sealed containers

NASA Astrophysics Data System (ADS)

Tucker, Brian J.; Diaz, Aaron A.; Eckenrode, Brian A.

2006-03-01

Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, hand-held, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.

Prototype instrument for noninvasive ultrasonic inspection and identification of fluids in sealed containers

NASA Astrophysics Data System (ADS)

Tucker, Brian J.; Diaz, Aaron A.; Eckenrode, Brian A.

2006-05-01

Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, handheld, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.

Micromachined 1-3 composites for ultrasonic air transducers

NASA Astrophysics Data System (ADS)

Haller, M. I.; Khuri-Yakub, B. T.

1994-06-01

Airborne ultrasound has many applications, such as robotic sensing, NDE, and gas flow measurements. Coupling of ultrasound into air from plane piston piezoelectric transducers is inefficient because of the large impedance mismatch between the piezoelectric and air, and the lack of appropriate matching materials. Standard design practice requires the use of a matching layer material with an acoustic impedance of approximately 0.02 MRayls and a thickness of a quarter-wavelength. Such materials are not readily available. A method to manufacture low impedance materials using micromachining techniques for matching piezoelectrics into air are presented here. These materials are capped 1-3 composites of air and Kapton(R). The acoustic effect of the cap is significant and necessitates a modified design technique. This technique involves the use of two matching layers with inverted acoustic impedances. Using the new fabrication technology and the new design technique, an 860-kHz transducer was fabricated with a one-way insertion loss of 17 dB and a fractional 3 dB bandwidth of 6%. It is believed that, using this technology, a transducer with a one-way insertion loss of 10 dB and a fractional bandwidth of 10% is possible.

Ultrasonic Resonance Spectrometry with Fourier Synthesized Pseudorandom Noise Excitation and Its Application to a Lyotropiec Liquid Crystal

NASA Astrophysics Data System (ADS)

Nakamura, Haruki; Naito, Yasushi; Tsuboi, Yukitoshi; Mitaku, Shigeki; Okano, Koji

1982-11-01

Time domain measurement to obtain ultrasonic resonance spectra was made using Fourier Synthesized Pseudorandom Noise (FSPN) excitation in order to observe the viscoelastic property of a lyotropic liquid crystal. The FSPN with multiple frequency components was amplitude-modulated by a carrier signal with a much higher single frequency component, and a quadrature detection technique was used to obtain a shear ultrasonic resonance spectrum produced between two transducers. A reflection method was applied to observe mechanical impedance of viscous and elastic materials at about 3 MHz. The viscosities obtained for standard viscous materials agreed well with literature values, and the rigidity and viscosity of a lyotropic liquid crystal of Sodium Lauryl Sulfate with water were measured; they were ˜ 106 dyn/cm2 and ˜0.1 P, respectively.

Real time monitoring of accelerated chemical reactions by ultrasonication-assisted spray ionization mass spectrometry.

PubMed

Lin, Shu-Hsuan; Lo, Ta-Ju; Kuo, Fang-Yin; Chen, Yu-Chie

2014-01-01

Ultrasonication has been used to accelerate chemical reactions. It would be ideal if ultrasonication-assisted chemical reactions could be monitored by suitable detection tools such as mass spectrometry in real time. It would be helpful to clarify reaction intermediates/products and to have a better understanding of reaction mechanism. In this work, we developed a system for ultrasonication-assisted spray ionization mass spectrometry (UASI-MS) with an ~1.7 MHz ultrasonic transducer to monitor chemical reactions in real time. We demonstrated that simply depositing a sample solution on the MHz-based ultrasonic transducer, which was placed in front of the orifice of a mass spectrometer, the analyte signals can be readily detected by the mass spectrometer. Singly and multiply charged ions from small and large molecules, respectively, can be observed in the UASI mass spectra. Furthermore, the ultrasonic transducer used in the UASI setup accelerates the chemical reactions while being monitored via UASI-MS. The feasibility of using this approach for real-time acceleration/monitoring of chemical reactions was demonstrated. The reactions of Girard T reagent and hydroxylamine with steroids were used as the model reactions. Upon the deposition of reactant solutions on the ultrasonic transducer, the intermediate/product ions are readily generated and instantaneously monitored using MS within 1 s. Additionally, we also showed the possibility of using this reactive UASI-MS approach to assist the confirmation of trace steroids from complex urine samples by monitoring the generation of the product ions. Copyright © 2014 John Wiley & Sons, Ltd.

Ultrasonic Nondestructive Evaluation Techniques Applied to the Quantitative Characterization of Textile Composite Materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1998-01-01

An overall goal of this research has been to enhance our understanding of the scientific principles necessary to develop advanced ultrasonic nondestructive techniques for the quantitative characterization of advanced composite structures. To this end, we have investigated a thin woven composite (5-harness biaxial weave). We have studied the effects that variations of the physical parameters of the experimental setup can have on the ultrasonic determination of the material properties for this thin composite. In particular, we have considered the variation of the nominal center frequency and the f-number of the transmitting transducer which in turn address issues such as focusing and beam spread of ultrasonic fields. This study has employed a planar, two-dimensional, receiving pseudo-array that has permitted investigation of the diffraction patterns of ultrasonic fields. Distortion of the ultrasonic field due to the spatial anisotropy of the thin composite has prompted investigation of the phenomenon of phase cancellation at the face of a finite-aperture, piezoelectric receiver. We have performed phase-sensitive and phase-insensitive analyses to provide a measure of the amount of phase cancellation at the face of a finite-aperture, piezoelectric receiver. The pursuit of robust measurements of received energy (i.e., those not susceptible to phase cancellation at the face of a finite-aperture, piezoelectric receiver) supports the development of robust techniques to determine material properties from measure ultrasonic parameters.

Applying a nonlinear, pitch-catch, ultrasonic technique for the detection of kissing bonds in friction stir welds.

PubMed

Delrue, Steven; Tabatabaeipour, Morteza; Hettler, Jan; Van Den Abeele, Koen

2016-05-01

Friction stir welding (FSW) is a promising technology for the joining of aluminum alloys and other metallic admixtures that are hard to weld by conventional fusion welding. Although FSW generally provides better fatigue properties than traditional fusion welding methods, fatigue properties are still significantly lower than for the base material. Apart from voids, kissing bonds for instance, in the form of closed cracks propagating along the interface of the stirred and heat affected zone, are inherent features of the weld and can be considered as one of the main causes of a reduced fatigue life of FSW in comparison to the base material. The main problem with kissing bond defects in FSW, is that they currently are very difficult to detect using existing NDT methods. Besides, in most cases, the defects are not directly accessible from the exposed surface. Therefore, new techniques capable of detecting small kissing bond flaws need to be introduced. In the present paper, a novel and practical approach is introduced based on a nonlinear, single-sided, ultrasonic technique. The proposed inspection technique uses two single element transducers, with the first transducer transmitting an ultrasonic signal that focuses the ultrasonic waves at the bottom side of the sample where cracks are most likely to occur. The large amount of energy at the focus activates the kissing bond, resulting in the generation of nonlinear features in the wave propagation. These nonlinear features are then captured by the second transducer operating in pitch-catch mode, and are analyzed, using pulse inversion, to reveal the presence of a defect. The performance of the proposed nonlinear, pitch-catch technique, is first illustrated using a numerical study of an aluminum sample containing simple, vertically oriented, incipient cracks. Later, the proposed technique is also applied experimentally on a real-life friction stir welded butt joint containing a kissing bond flaw. Copyright © 2016 Elsevier B.V. All rights reserved.

Damage detection in composites using nonlinear ultrasonically modulated thermography

NASA Astrophysics Data System (ADS)

Malfense Fierro, G.-P.; Dionysopoulos, D.; Meo, M.; Ciampa, F.

2018-03-01

This paper proposes a novel nonlinear ultrasonically stimulated thermography technique for a quick and reliable assessment of material damage in carbon fibre reinforced plastic (CFRP) composite materials. The proposed nondestructive evaluation (NDE) method requires narrow sweep ultrasonic excitation using contact piezoelectric transducers in order to identify dual excitation frequencies associated with the damage resonance. High-amplitude signals and higher harmonic generation are necessary conditions for an accurate identification of these two input frequencies. Dual periodic excitation using high- and low-frequency input signals was then performed in order to generate frictional heating at the crack location that was measured by an infrared (IR) camera. To validate this concept, an impact damaged CFRP composite panel was tested and the experimental results were compared with traditional flash thermography. A laser vibrometer was used to investigate the response of the material with dual frequency excitation. The proposed nonlinear ultrasonically modulated thermography successfully detected barely visible impact damage in CFRP composites. Hence, it can be considered as an alternative to traditional flash thermography and thermosonics by allowing repeatable detection of damage in composites.

A study of PC-based ultrasonic goniometer system of surface properties and characterization of materials

NASA Astrophysics Data System (ADS)

Sani, S.; Saad, M. H. Md; Jamaludin, N.; Ismail, M. P.; Mohd, S.; Mustapha, I.; Masenwat, N. A.; Tengku Amran, T. S.; Megat Ahmad, M. H. A.

2018-01-01

This paper discussed the design and development of a portable PC-based ultrasonic goniometer system that can be used to study material properties using ultrasonic wave. The system utilizes an ultrasonic pulse-receiver card model attached to computer notebook for signal display. A new specific software package (GoNIO) was developed to control the operation of the scanner, displaying the data and analyze characteristics of materials. System testing was carried out using samples with cubic dimension of about 10 mm x 20 mm x 30 mm. This size allows the sample to be fitted into the goniometer specimen holder and immersed in a liquid during measurement. The sample was rotated from incident angle of 0° to 90° during measurement and the amplitude reflected signals were recorded at every one degree of rotation. Immersion transducers were used to generate and receive the ultrasounds that pass through the samples. Longitudinal, shear and Rayleigh wave measurements were performed on the samples to determine the Dynamic Young’s Modulus. Results of measurements are explained and discussed.

Characterization of the acoustic field generated by a horn shaped ultrasonic transducer

NASA Astrophysics Data System (ADS)

Hu, B.; Lerch, J. E.; Chavan, A. H.; Weber, J. K. R.; Tamalonis, A.; Suthar, K. J.; DiChiara, A. D.

2017-09-01

A horn shaped Langevin ultrasonic transducer used in a single axis levitator was characterized to better understand the role of the acoustic profile in establishing stable traps. The method of characterization included acoustic beam profiling performed by raster scanning an ultrasonic microphone as well as finite element analysis of the horn and its interface with the surrounding air volume. The results of the model are in good agreement with measurements and demonstrate the validity of the approach for both near and far field analyses. Our results show that this style of transducer produces a strong acoustic beam with a total divergence angle of 10°, a near-field point close to the transducer surface and a virtual sound source. These are desirable characteristics for a sound source used for acoustic trapping experiments.

Characterization of the acoustic field generated by a horn shaped ultrasonic transducer

DOE PAGES

Hu, B.; Lerch, J. E.; Chavan, A. H.; ...

2017-09-04

A horn shaped Langevin ultrasonic transducer used in a single axis levitator was characterized to better understand the role of the acoustic profile in establishing stable traps. The method of characterization included acoustic beam profiling performed by raster scanning an ultrasonic microphone as well as finite element analysis of the horn and its interface with the surrounding air volume. The results of the model are in good agreement with measurements and demonstrate the validity of the approach for both near and far field analysis. Our results show that this style of transducer produces a strong acoustic beam with a totalmore » divergence angle of 10 degrees, a nearfield point close to the transducer surface and a virtual sound source. These are desirable characteristics for a sound source used for acoustic trapping experiments.« less

Characterization of the acoustic field generated by a horn shaped ultrasonic transducer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, B.; Lerch, J. E.; Chavan, A. H.

A horn shaped Langevin ultrasonic transducer used in a single axis levitator was characterized to better understand the role of the acoustic profile in establishing stable traps. The method of characterization included acoustic beam profiling performed by raster scanning an ultrasonic microphone as well as finite element analysis of the horn and its interface with the surrounding air volume. The results of the model are in good agreement with measurements and demonstrate the validity of the approach for both near and far field analyses. Our results show that this style of transducer produces a strong acoustic beam with a totalmore » divergence angle of 10 degree, a near-field point close to the transducer surface and a virtual sound source. These are desirable characteristics for a sound source used for acoustic trapping experiments« less

Characterization of the acoustic field generated by a horn shaped ultrasonic transducer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, B.; Lerch, J. E.; Chavan, A. H.

A horn shaped Langevin ultrasonic transducer used in a single axis levitator was characterized to better understand the role of the acoustic profile in establishing stable traps. The method of characterization included acoustic beam profiling performed by raster scanning an ultrasonic microphone as well as finite element analysis of the horn and its interface with the surrounding air volume. The results of the model are in good agreement with measurements and demonstrate the validity of the approach for both near and far field analysis. Our results show that this style of transducer produces a strong acoustic beam with a totalmore » divergence angle of 10 degrees, a nearfield point close to the transducer surface and a virtual sound source. These are desirable characteristics for a sound source used for acoustic trapping experiments.« less

Microscale 1-3-Type (Na,K)NbO(3)-Based Pb-Free Piezocomposites for High-Frequency Ultrasonic Transducer Applications.

PubMed

Shen, Zong-Yang; Li, Jing-Feng; Chen, Ruimin; Zhou, Qifa; Shung, K Kirk

2011-05-01

Fine-grained Pb-free (Na(0.535)K(0.485))(0.95)Li(0.05)(Nb(0.8)Ta(0.2))O(3) (NKLNT) piezoceramics prepared by spark plasma sintering (SPS) technique was used to fabricate NKLNT/epoxy 1-3 composites with a modified dice-fill method. Because of its good machinability, SPSed NKLNT ceramic rods could be miniaturized to a lateral width of 50 µm. After lapping down to 56 µm in thickness, the composite was used to fabricate an ultrasonic transducer as the active piezoelectric element. This composite transducer showed a bandwidth at -6 dB nearly 90%at a center frequency of 29 MHz, demonstrating that this Pb-free composite thick film is very promising for the fabrication of high-frequency ultrasonic transducers in medical imaging applications.

Advanced Ultrasonic Measurement Methodology for Non-Invasive Interrogation and Identification of Fluids in Sealed Containers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tucker, Brian J.; Diaz, Aaron A.; Eckenrode, Brian A.

2006-03-16

The Hazardous Materials Response Unit (HMRU) and the Counterterrorism and Forensic Science Research Unit (CTFSRU), Laboratory Division, Federal Bureau of Investigation (FBI) have been mandated to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a portable, hand-held, hazardous materials acoustic inspection device (HAZAID) that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as wellmore » as container sizes and materials, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The HAZAID prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the HAZAID prototype. High bandwidth ultrasonic transducers combined with the advanced pulse compression technique allowed researchers to 1) impart large amounts of energy, 2) obtain high signal-to-noise ratios, and 3) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of this feasibility study demonstrated that the HAZAID experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.« less

Design and Performance Analysis of an Intrinsically Safe Ultrasonic Ranging Sensor

PubMed Central

Zhang, Hongjuan; Wang, Yu; Zhang, Xu; Wang, Dong; Jin, Baoquan

2016-01-01

In flammable or explosive environments, an ultrasonic sensor for distance measurement poses an important engineering safety challenge, because the driving circuit uses an intermediate frequency transformer as an impedance transformation element, in which the produced heat or spark is available for ignition. In this paper, an intrinsically safe ultrasonic ranging sensor is designed and implemented. The waterproof piezoelectric transducer with integrated transceiver is chosen as an energy transducing element. Then a novel transducer driving circuit is designed based on an impedance matching method considering safety spark parameters to replace an intermediate frequency transformer. Then, an energy limiting circuit is developed to achieve dual levels of over-voltage and over-current protection. The detail calculation and evaluation are executed and the electrical characteristics are analyzed to verify the intrinsic safety of the driving circuit. Finally, an experimental platform of the ultrasonic ranging sensor system is constructed, which involves short-circuit protection. Experimental results show that the proposed ultrasonic ranging sensor is excellent in both ranging performance and intrinsic safety. PMID:27304958

Design and Performance Analysis of an Intrinsically Safe Ultrasonic Ranging Sensor.

PubMed

Zhang, Hongjuan; Wang, Yu; Zhang, Xu; Wang, Dong; Jin, Baoquan

2016-06-13

In flammable or explosive environments, an ultrasonic sensor for distance measurement poses an important engineering safety challenge, because the driving circuit uses an intermediate frequency transformer as an impedance transformation element, in which the produced heat or spark is available for ignition. In this paper, an intrinsically safe ultrasonic ranging sensor is designed and implemented. The waterproof piezoelectric transducer with integrated transceiver is chosen as an energy transducing element. Then a novel transducer driving circuit is designed based on an impedance matching method considering safety spark parameters to replace an intermediate frequency transformer. Then, an energy limiting circuit is developed to achieve dual levels of over-voltage and over-current protection. The detail calculation and evaluation are executed and the electrical characteristics are analyzed to verify the intrinsic safety of the driving circuit. Finally, an experimental platform of the ultrasonic ranging sensor system is constructed, which involves short-circuit protection. Experimental results show that the proposed ultrasonic ranging sensor is excellent in both ranging performance and intrinsic safety.

Ultrasonic assessment of additive manufactured Ti-6Al-4V

NASA Astrophysics Data System (ADS)

Schehl, Norman; Kramb, Vicki; Dierken, Josiah; Aldrin, John; Schwalbach, Edwin; John, Reji

2018-04-01

Additive Manufacturing (AM) processes offer the potential for manufacturing cost savings and rapid insertion into service through production of near net shape components for complicated structures. Use of these parts in high reliability applications such as those in the aerospace industry will require nondestructive characterization methods to ensure post-process material quality in as-built condition. Ultrasonic methods can be used for this quality verification. Depending on the application, the service life of AM components can be sensitive to the part surface condition. The surface roughness and layered structure inherent to the electron-beam powder-bed fusion process necessitates new approaches to evaluate subsurface material integrity in its presence. Experimental methods and data analytics may improve the evaluation of as-built additively manufactured materials. This paper discusses the assessment of additively manufactured EBM Ti-6Al-4V panels using ultrasonic methods and the data analytics applied to evaluate material integrity. The assessment was done as an exploratory study as the discontinuities of interest in these test samples were not known when the measurements were performed. Water immersion ultrasonic techniques, including pulse-echo and through transmission with 10 MHz focused transducers, were used to explore the material integrity of as-built plates. Subsequent destructive mechanical tests of specimens extracted from the plates provided fracture locations indicating critical flaws. To further understand the effect of surface-roughness, an evaluation of ultrasonic response in the presence of as-built surfaces and with the surface removed was performed. The assessment of additive manufactured EBM Ti-6Al-4V panels with ultrasonic techniques indicated that ultrasonic energy was attenuated by the as-built surface roughness. In addition, feature detection was shown to be sensitive to experimental ultrasonic parameters and flaw morphology.

Mid-IR laser ultrasonic testing for fiber reinforced plastics

NASA Astrophysics Data System (ADS)

Kusano, Masahiro; Hatano, Hideki; Oguchi, Kanae; Yamawaki, Hisashi; Watanabe, Makoto; Enoki, Manabu

2018-04-01

Ultrasonic testing is the most common method to detect defects in materials and evaluate their sizes and locations. Since piezo-electric transducers are manually handled from point to point, it takes more costs for huge products such as airplanes. Laser ultrasonic testing (LUT) is a breakthrough technique. A pulsed laser generates ultrasonic waves on a material surface due to thermoelastic effect or ablation. The ultrasonic waves can be detected by another laser with an interferometer. Thus, LUT can realize instantaneous inspection without contacting a sample. A pulse laser with around 3.2 μm wavelength (in the mid-IR range) is more suitable to generate ultrasonic waves for fiber reinforced plastics (FRPs) because the light is well absorbed by the polymeric matrix. On the other hand, such a laser is not available in the market. In order to emit the mid-IR laser pulse, we came up with the application of an optical parametric oscillator and developed an efficient wavelength conversion device by pumping a compact Nd:YAG solid-state laser. Our mid-IR LUT system is most suitable for inspection of FRPs. The signal-to-noise ratio of ultrasonic waves generated by the mid-IR laser is higher than that by the Nd:YAG laser. The purpose of the present study is to evaluate the performance of the mid-IR LUT system in reflection mode. We investigated the effects of the material properties and the laser properties on the generated ultrasonic waves. In addition, C-scan images by the system were also presented.

Detection of cystic structures using pulsed ultrasonically induced resonant cavitation

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph (Inventor); Kovach, John S. (Inventor)

2002-01-01

Apparatus and method for early detection of cystic structures indicative of ovarian and breast cancers uses ultrasonic wave energy at a unique resonance frequency for inducing cavitation in cystic fluid characteristic of cystic structures in the ovaries associated with ovarian cancer, and in cystic structures in the breast associated with breast cancer. Induced cavitation bubbles in the cystic fluid implode, creating implosion waves which are detected by ultrasonic receiving transducers attached to the abdomen of the patient. Triangulation of the ultrasonic receiving transducers enables the received signals to be processed and analyzed to identify the location and structure of the cyst.

Modal analysis and nonlinear characterization of an airborne power ultrasonic transducer with rectangular plate radiator.

PubMed

Andrés, R R; Acosta, V M; Lucas, M; Riera, E

2018-01-01

Some industrial processes like particle agglomeration or food dehydration among others can be enhanced by the use of power ultrasonic technologies. These technologies are based on an airborne power ultrasonic transducer (APUT) constituted by a pre-stressed Langevin-type transducer, a mechanical amplifier and an extensive plate radiator. In order to produce the desired effects in industrial processing, the transducer has to vibrate in an extensional mode driving an extensive radiator in the desired flexural mode with high amplitude displacements. Due to the generation of these high amplitude displacements in the radiator surfaces, non-linear effects like frequency shifts, hysteresis or modal interactions, among others, may be produced in the transducer behavior. When any nonlinear effect appears, when applying power, the stability and efficiency of this ultrasonic technology decreases, and the transducer may be damaged depending on the excitation power level and the nature of the nonlinearity. In this paper, an APUT with flat rectangular radiator is presented, as the active part of an innovative system with stepped reflectors. The nonlinear behavior of the APUT has been characterized numerically and experimentally in case of the modal analysis and experimentally in the case of dynamic analysis. According to the results obtained after the experiments, no modal interactions are expected, nor do other nonlinear effects. Copyright © 2017 Elsevier B.V. All rights reserved.

Determination of the sonic properties of a Nigerian quartz for ultrasonic transducer.

PubMed

Nwadike, Uchechukwu I; Agwu, Kenneth K; Eze, Charles U; Kani, Duke; Agu, Gregory; Enwereuzo, Emmanuel; Obika, Mike; Umoh, Effiong; Ufomba, Emmanuel

2018-03-15

There is abundant quartz deposit in Nigeria which has been used for export and building purposes. However, its electrical and piezoelectric properties have not been studied. Thus, whether it can be used as raw material for the indigenous electric industries is unknown to date. This study aims to characterize the piezoelectric properties of smoky quartz for ultrasonic transducer and determine its sonic properties. In the research approach, the raw quartz was cut into six crystals of rectangular shape using a universal cutter. The crystals were purified with a 100 ml hydrofluoric and hydrochloric acid solution under a temperature of 250°C in a furnace. The sizes, weights, and capacitance of crystals were determined using the standard measuring instruments. The resonance method was used for the determination of the frequency of minimum and maximum impedance of the crystals. The piezoelectric constants of the crystals were derived using the standard formula for determination of piezoelectric constants. The results show that the sonic properties represented by the piezoelectric charge constant (d31) and the piezoelectric voltage constant (g31) values are 2.52 (±1.075) ×10-8c/m2 and 1030.6114 ± 250.89v/m2 respectively. The present study has characterized Nigerian quartz for its piezoelectric properties and found that it was suitable for use in the construction of ultrasonic transducers.

Gel-Filled Holders For Ultrasonic Transducers

NASA Technical Reports Server (NTRS)

Companion, John A.

1992-01-01

In new technique, ultrasonic transducer embedded in rubbery, castable, low-loss gel to enable transducer to "look" into surface of test object or human body at any desired angle. Composed of solution of water and ethylene glycol in collagen matrix. Provides total contact of water bath, also used on bodies or objects too large for water baths, even if moving. Also provides look angles of poly(methyl methacrylate) angle block with potential of reduced acoustic impedance and refraction. Custom-tailored to task at hand, and gel sufficiently inexpensive to be discarded upon completion. Easy to couple ultrasound in and out of gel, minimizing losses and artifacts of other types of standoffs employed in ultrasonic testing.

Design and numerical simulation of novel giant magnetostrictive ultrasonic transducer

NASA Astrophysics Data System (ADS)

Li, Pengyang; Liu, Qiang; Li, Shujuan; Wang, Quandai; Zhang, Dongya; Li, Yan

This paper provides a design method of a novel giant magnetostrictive ultrasonic transducer utilized in incremental sheet metal forming. The frequency equations of the ultrasonic vibrator were deduced and the corresponding correctness verified by the modal and harmonic response characteristic through the finite element method (FEM) and ANSYS software. In addition, the magnetic field of the vibrator system was designed and verified by the ANSYS. Finally, the frequency tests based on the impedance response analysis and the amplitude measurements based on the laser displacement sensor were performed on the prototype. The results confirmed the appropriate design of this transducer, setting the foundation for a low mechanical quality factor and satisfying amplitude.

Ultrasonic Apparatus and Method to Assess Compartment Syndrome

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Ueno, Toshiaki (Inventor); Hargens, Alan R. (Inventor)

2009-01-01

A process and apparatus for measuring pressure buildup in a body compartment that encases muscular tissue. The method includes assessing the body compartment configuration and identifying the effect of pulsatible components on compartment dimensions and muscle tissue characteristics. This process is used in preventing tissue necrosis, and in decisions of whether to perform surgery on the body compartment for prevention of Compartment Syndrome. An apparatus is used for measuring pressure build-up in the body compartment having components for imparting ultrasonic waves such as a transducer, placing the transducer to impart the ultrasonic waves, capturing the imparted ultrasonic waves, mathematically manipulating the captured ultrasonic waves and categorizing pressure build-up in the body compartment from the mathematical manipulations.

Research on Dust Concentration Measurement Technique Based on the Theory of Ultrasonic Attenuation

NASA Astrophysics Data System (ADS)

Zhang, Yan; Lou, Wenzhong; Liao, Maohao

2018-03-01

In this paper, a method of characteristics dust concentration is proposed, which based on ultrasonic changes of MEMS piezoelectric ultrasonic transducer. The principle is that the intensity of the ultrasonic will produce attenuation with the propagation medium and propagation distance, the attenuation coefficient is affect by dust concentration. By detecting the changes of ultra acoustic in the dust, the concentration of the dust is calculate by the attenuation-concentration model, and the EACH theory model is based on this principle. The experimental results show that the MEMS piezoelectric ultrasonic transducer can be use for dust concentration of 100-900 g/m3 detection, the deviation between theory and experiments is smaller than 10.4%.

Improved formula for continuous-wave measurements of ultrasonic phase velocity

NASA Technical Reports Server (NTRS)

Chern, E. J.; Cantrell, J. H., Jr.; Heyman, J. S.

1981-01-01

An improved formula for continuous-wave ultrasonic phase velocity measurements using contact transducers is derived from the transmission line theory. The effect of transducer-sample coupling bonds is considered for measurements of solid samples even though it is often neglected because of the difficulty of accurately determining the bond thickness. Computer models show that the present formula is more accurate than previous expressions. Laboratory measurements using contacting transducers with the present formula are compared to measurements using noncontacting (hence effectively correction-free) capacitive transducers. The results of the experiments verify the validity and accuracy of the new formula.

Biasing and fast degaussing circuit for magnetic materials

DOEpatents

Dress, Jr., William B.; McNeilly, David R.

1984-01-01

A dual-function circuit is provided which may be used to both magnetically bias and alternately, quickly degauss a magnetic device. The circuit may be magnetically coupled or directly connected electrically to a magnetic device, such as a magnetostrictive transducer, to magnetically bias the device by applying a d.c. current and alternately apply a selectively damped a.c. current to the device to degauss the device. The circuit is of particular value in many systems which use magnetostrictive transducers for ultrasonic transmission in different propagation modes over very short time periods.

Biasing and fast degaussing circuit for magnetic materials

DOEpatents

Dress, W.B. Jr.; McNeilly, D.R.

1983-10-04

A dual-function circuit is provided which may be used to both magnetically bias and alternately, quickly degauss a magnetic device. The circuit may be magnetically coupled or directly connected electrically to a magnetic device, such as a magnetostrictive transducer, to magnetically bias the device by applying a dc current and alternately apply a selectively damped ac current to the device to degauss the device. The circuit is of particular value in many systems which use magnetostrictive transducers for ultrasonic transmission in different propagation modes over very short time periods.

Assessing the relationship between the inter-rod coupling and the efficiency of piezocomposite high-intensity focused ultrasound transducers.

PubMed

Chen, Gin-Shin; Pan, Chia-Ching; Lin, Yu-Li; Cheng, Jung-Sung

2014-03-01

The electroacoustic conversion efficiency of the ultrasonic transducer is a critical performance index for high-power applications. The material properties, volume fraction (VF) and aspect ratio (AR) are typically regarded as the design parameters of the piezocomposite transducer. We hypothesized that the spacing between piezoelectric rods was also a dominant factor. Therefore, the inter-rod coupling effects on the efficiency of 1-3 piezocomposite ultrasonic transducers were investigated in this study. The efficiencies of six flat and three curved 1.0 MHz PZT4 epoxy composite transducers with different geometric parameters were measured. Finite element transient analyses of the inter-rod electrical-mechanical coupling in the composites were carried out to explain the measured results. The experimental results showed that for 0.47 AR, the 79% VF transducers had lower efficiency than the 64% VF and 53% VF transducers. For 0.19 AR, the efficiency of the 59% VF transducer was not greater than the efficiency of the 39% VF transducer. Numerical analyses demonstrated that the positive peak voltage induced by the coupling of the side rods was more than twice the level induced by the coupling of the diagonal rods for any spacing. The diagonal coupling voltage peak did not change for spacings larger than 0.2 mm. Moreover, for spacings of 0.05 and 0.1 mm, the inter-rod coupling caused 24% and 20% waveform shifts of the driving voltage, respectively, while the 0.2 mm spacing coupling caused a 14% reduction in the amplitude of the driving voltage. As a result, the asymmetry of the driving voltage degraded the efficiency of the composite transducers and became more severe when the spacing was decreased. We concluded that the efficiency loss induced by inter-rod coupling as a function of spacing should be considered when designing piezocomposite transducers. Copyright © 2013 Elsevier B.V. All rights reserved.

Apparatus for checking the direction of polarization of shear-wave ultrasonic transducers

DOEpatents

Karplus, H.H.B.; Forster, G.A.

An apparatus for checking the direction of polarization of shear-wave ultrasonic transducers comprises a first planar surface for mounting the shear-wave transducer, a second planar surface inclined at a predetermined angle to the first surface to generate longitudinal waves by mode conversion, and a third planar surface disposed at a second predetermined angle to the first for mounting a longitudinal-wave ultransonic transducer. In an alternate embodiment, two second planar surfaces at the predetermined angle are placed at an angle to each other. The magnitude of the shear wave is a function of the angle between the direction of polarization of the transducer and the mode-conversion surface.

A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet.

PubMed

Liu, Yingxiang; Liu, Junkao; Chen, Weishan; Shi, Shengjun

2012-05-01

A U-shaped linear ultrasonic motor using longitudinal vibration transducers with double feet was proposed in this paper. The proposed motor contains a horizontal transducer and two vertical transducers. The horizontal transducer includes two exponential shape horns located at the leading ends, and each vertical transducer contains one exponential shape horn. The horns of the horizontal transducer and the vertical transducer intersect at the tip ends where the driving feet are located. Longitudinal vibrations are superimposed in the motor and generate elliptical motions at the driving feet. The two vibration modes of the motor are discussed, and the motion trajectories of driving feet are deduced. By adjusting the structural parameters, the resonance frequencies of two vibration modes were degenerated. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 854 mm/s and maximum thrust force of 40 N at a voltage of 200 V(rms).

Micromachining Techniques in Developing High-Frequency Piezoelectric Composite Ultrasonic Array Transducers

PubMed Central

Liu, Changgeng; Djuth, Frank T.; Zhou, Qifa; Shung, K. Kirk

2014-01-01

Several micromachining techniques for the fabrication of high-frequency piezoelectric composite ultrasonic array transducers are described in this paper. A variety of different techniques are used in patterning the active piezoelectric material, attaching backing material to the transducer, and assembling an electronic interconnection board for transmission and reception from the array. To establish the feasibility of the process flow, a hybrid test ultrasound array transducer consisting of a 2-D array having an 8 × 8 element pattern and a 5-element annular array was designed, fabricated, and assessed. The arrays are designed for a center frequency of ~60 MHz. The 2-D array elements are 105 × 105 μm in size with 5-μm kerfs between elements. The annular array surrounds the square 2-D array and provides the option of transmitting from the annular array and receiving with the 2-D array. Each annular array element has an area of 0.71 mm2 with a 16-μm kerf between elements. The active piezoelectric material is (1 − x) Pb(Mg1/3Nb2/3)O3−xPbTiO3 (PMN-PT)/epoxy 1–3 composite with a PMN-PT pillar lateral dimension of 8 μm and an average gap width of ~4 μm, which was produced by deep reactive ion etching (DRIE) dry etching techniques. A novel electric interconnection strategy for high-density, small-size array elements was proposed. After assembly, the array transducer was tested and characterized. The capacitance, pulse–echo responses, and crosstalk were measured for each array element. The desired center frequency of ~60 MHz was achieved and the −6-dB bandwidth of the received signal was ~50%. At the center frequency, the crosstalk between adjacent 2-D array elements was about −33 dB. The techniques described herein can be used to build larger arrays containing smaller elements. PMID:24297027

Flexible metallic ultrasonic transducers for structural health monitoring of pipes at high temperatures.

PubMed

Shih, Jeanne-Louise; Kobayashi, Makiko; Jen, Cheng-Kuei

2010-09-01

Piezoelectric films have been deposited by a sol-gel spray technique onto 75-μm-thick titanium and stainless steel (SS) membranes and have been fabricated into flexible ultrasonic transducers (FUTs). FUTs using titanium membranes were glued and those using SS membranes brazed onto steel pipes, procedures that serve as on-site installation techniques for the purpose of offering continuous thickness monitoring capabilities at up to 490 °C. At 150 °C, the thickness measurement accuracy of a pipe with an outer diameter of 26.6 mm and a wall thickness of 2.5 mm was estimated to be 26 μm and the center frequency of the FUT was 10.8 MHz. It is demonstrated that the frequency bandwidth of the FUTs and SNR of signals using glue or brazing materials as high-temperature couplant for FUTs are sufficient to inspect the steel pipes even with a 2.5 mm wall thickness.

Acoustooptic pulse-echo transducer system

NASA Technical Reports Server (NTRS)

Claus, R. O.; Wade, J. C.

1983-01-01

A pulse-echo transducer system which uses an ultrasonic generating element and an optical detection technique is described. The transmitting transducer consists of a concentric ring electrode pattern deposited on a circular, X-cut quartz substrate with a circular hole in the center. The rings are independently pulsed with a sequence high voltage signals phased in such a way that the ultrasonic waves generated by the separate rings superimpose to produce a composite field which is focused at a controllable distance below the surface of the specimen. The amplitude of the field reflected from this focus position is determined by the local reflection coefficient of the medium at the effective focal point. By processing the signals received for a range of ultrasonic transducer array focal lengths, the system can be used to locate and size anomalies within solids and liquids. Applications in both nondestructive evaluation and biomedical scanning are suggested.

Defect Inspection of Flip Chip Solder Bumps Using an Ultrasonic Transducer

PubMed Central

Su, Lei; Shi, Tielin; Xu, Zhensong; Lu, Xiangning; Liao, Guanglan

2013-01-01

Surface mount technology has spurred a rapid decrease in the size of electronic packages, where solder bump inspection of surface mount packages is crucial in the electronics manufacturing industry. In this study we demonstrate the feasibility of using a 230 MHz ultrasonic transducer for nondestructive flip chip testing. The reflected time domain signal was captured when the transducer scanning the flip chip, and the image of the flip chip was generated by scanning acoustic microscopy. Normalized cross-correlation was used to locate the center of solder bumps for segmenting the flip chip image. Then five features were extracted from the signals and images. The support vector machine was adopted to process the five features for classification and recognition. The results show the feasibility of this approach with high recognition rate, proving that defect inspection of flip chip solder bumps using the ultrasonic transducer has high potential in microelectronics packaging.

A novel serrated columnar phased array ultrasonic transducer

NASA Astrophysics Data System (ADS)

Zou, Cheng; Sun, Zhenguo; Cai, Dong; Song, Hongwei; Chen, Qiang

2016-02-01

Traditionally, wedges are required to generate transverse waves in a solid specimen and mechanical rotation device is needed for interrogation of a specimen with a hollow bore, such as high speed railway locomotive axles, turbine rotors, etc. In order to eliminate the mechanical rotation process, a novel array pattern of phased array ultrasonic transducers named as serrated columnar phased array ultrasonic transducer (SCPAUT) is designed. The elementary transducers are planar rectangular, located on the outside surface of a cylinder. This layout is aimed to generate electrically rotating transverse waveforms so as to inspect the longitudinal cracks on the outside surface of a specimen which has a hollow bore at the center, such as the high speed railway locomotive axles. The general geometry of the SCPAUT and the inspection system are illustrated. A FEM model and mockup experiment has been carried out. The experiment results are in good agreement with the FEM simulation results.

Ultrasonic transducer with laminated coupling wedge

DOEpatents

Karplus, Henry H. B.

1976-08-03

An ultrasonic transducer capable of use in a high-temperature environment incorporates a laminated metal coupling wedge including a reflecting edge shaped as a double sloping roof and a transducer crystal backed by a laminated metal sound absorber disposed so as to direct sound waves through the coupling wedge and into a work piece, reflections from the interface between the coupling wedge and the work piece passing to the reflecting edge. Preferably the angle of inclination of the two halves of the reflecting edge are different.

Ultrasonic transducer

DOEpatents

Taylor, Steven C.; Kraft, Nancy C.

2007-03-13

An ultrasonic transducer having an effective center frequency of about 42 MHz; a bandwidth of greater than 85% at 6 dB; a spherical focus of at least 0.5 inches in water; an F4 lens; a resolution sufficient to be able to detect and separate a 0.005 inch flat-bottomed hole at 0.005 inches below surface; and a beam size of approximately 0.006–0.008 inches measured off a 11/2 mm ball in water at the transducer's focal point.

Optimal resonance configuration for ultrasonic wireless power transmission to millimeter-sized biomedical implants.

PubMed

Miao Meng; Kiani, Mehdi

2016-08-01

In order to achieve efficient wireless power transmission (WPT) to biomedical implants with millimeter (mm) dimensions, ultrasonic WPT links have recently been proposed. Operating both transmitter (Tx) and receiver (Rx) ultrasonic transducers at their resonance frequency (fr) is key in improving power transmission efficiency (PTE). In this paper, different resonance configurations for Tx and Rx transducers, including series and parallel resonance, have been studied to help the designers of ultrasonic WPT links to choose the optimal resonance configuration for Tx and Rx that maximizes PTE. The geometries for disk-shaped transducers of four different sets of links, operating at series-series, series-parallel, parallel-series, and parallel-parallel resonance configurations in Tx and Rx, have been found through finite-element method (FEM) simulation tools for operation at fr of 1.4 MHz. Our simulation results suggest that operating the Tx transducer with parallel resonance increases PTE, while the resonance configuration of the mm-sized Rx transducer highly depends on the load resistance, Rl. For applications that involve large Rl in the order of tens of kΩ, a parallel resonance for a mm-sized Rx leads to higher PTE, while series resonance is preferred for Rl in the order of several kΩ and below.

A parallel-architecture parametric equalizer for air-coupled capacitive ultrasonic transducers.

PubMed

McSweeney, Sean G; Wright, William M D

2012-01-01

Parametric equalization is rarely applied to ultrasonic transducer systems, for which it could be used on either the transmitter or the receiver to achieve a desired response. An optimized equalizer with both bump and cut capabilities would be advantageous for ultrasonic systems in applications in which variations in the transducer performance or the properties of the propagating medium produce a less-than-desirable signal. Compensation for non-ideal transducer response could be achieved using equalization on a device-by-device basis. Additionally, calibration of ultrasonic systems in the field could be obtained by offline optimization of equalization coefficients. In this work, a parametric equalizer for ultrasonic applications has been developed using multiple bi-quadratic filter elements arranged in a novel parallel arrangement to increase the flexibility of the equalization. The equalizer was implemented on a programmable system-on-chip (PSOC) using a small number of parallel 4th-order infinite impulse response switchedcapacitor band-pass filters. Because of the interdependency of the required coefficients for the switched capacitors, particle swarm optimization (PSO) was used to determine the optimum values. The response of a through-transmission system using air-coupled capacitive ultrasonic transducers was then equalized to idealized Hamming function or brick-wall frequencydomain responses. In each case, there was excellent agreement between the equalized signals and the theoretical model, and the fidelity of the time-domain response was maintained. The bandwidth and center frequency response of the system were significantly improved. It was also shown that the equalizer could be used on either the transmitter or the receiver, and the system could compensate for the effects of transmitterreceiver misalignment. © 2012 IEEE

Design and Optimization of Ultrasonic Wireless Power Transmission Links for Millimeter-Sized Biomedical Implants.

PubMed

Meng, Miao; Kiani, Mehdi

2017-02-01

Ultrasound has been recently proposed as an alternative modality for efficient wireless power transmission (WPT) to biomedical implants with millimeter (mm) dimensions. This paper presents the theory and design methodology of ultrasonic WPT links that involve mm-sized receivers (Rx). For given load (R L ) and powering distance (d), the optimal geometries of transmitter (Tx) and Rx ultrasonic transducers, including their diameter and thickness, as well as the optimal operation frequency (f c ) are found through a recursive design procedure to maximize the power transmission efficiency (PTE). First, a range of realistic f c s is found based on the Rx thickness constrain. For a chosen f c within the range, the diameter and thickness of the Rx transducer are then swept together to maximize PTE. Then, the diameter and thickness of the Tx transducer are optimized to maximize PTE. Finally, this procedure is repeated for different f c s to find the optimal f c and its corresponding transducer geometries that maximize PTE. A design example of ultrasonic link has been presented and optimized for WPT to a 1 mm 3 implant, including a disk-shaped piezoelectric transducer on a silicon die. In simulations, a PTE of 2.11% at f c of 1.8 MHz was achieved for R L of 2.5 [Formula: see text] at [Formula: see text]. In order to validate our simulations, an ultrasonic link was optimized for a 1 mm 3 piezoelectric transducer mounted on a printed circuit board (PCB), which led to simulated and measured PTEs of 0.65% and 0.66% at f c of 1.1 MHz for R L of 2.5 [Formula: see text] at [Formula: see text], respectively.

Mode-converted diffuse ultrasonic backscatter.

PubMed

Hu, Ping; Kube, Christopher M; Koester, Lucas W; Turner, Joseph A

2013-08-01

Diffuse ultrasonic backscatter describes the scattering of elastic waves from interfaces within heterogeneous materials. Previously, theoretical models have been developed for the diffuse backscatter of longitudinal-to-longitudinal (L-L) wave scattering within polycrystalline materials. Following a similar formalism, a mode-conversion scattering model is presented here to quantify the component of an incident longitudinal wave that scatters and is converted to a transverse (shear) wave within a polycrystalline sample. The model is then used to fit experimental measurements associated with a pitch-catch transducer configuration performed using a sample of 1040 steel. From these measurements, an average material correlation length is determined. This value is found to be in agreement with results from L-L scattering measurements and is on the order of the grain size as determined from optical micrographs. Mode-converted ultrasonic backscatter is influenced much less by the front-wall reflection than an L-L measurement and it provides additional microstructural information that is not accessible in any other manner.

Indoor Airborne Ultrasonic Wireless Communication Using OFDM Methods.

PubMed

Jiang, Wentao; Wright, William M D

2017-09-01

Concerns still exist over the safety of prolonged exposure to radio frequency (RF) wireless transmissions and there are also potential data security issues due to remote signal interception techniques such as Bluesniping. Airborne ultrasound may be used as an alternative to RF for indoor wireless communication systems for securely transmitting data over short ranges, as signals are difficult to intercept from outside the room. Two types of air-coupled capacitive ultrasonic transducer were used in the implementation of an indoor airborne wireless communication system. One was a commercially available SensComp series 600 ultrasonic transducer with a nominal frequency of 50 kHz, and the other was a prototype transducer with a high- k dielectric layer operating at higher frequencies from 200 to 400 kHz. Binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), and quadrature amplitude modulation (QAM)-based orthogonal frequency division multiplexing modulation methods were successfully implemented using multiple orthogonal subchannels. The modulated ultrasonic signal packets were synchronized using a wireless link, and a least-squares channel estimation algorithm was used to compensate the phase and amplitude distortion introduced by the air channel. By sending and receiving the ultrasonic signals using the SensComp transducers, the achieved maximum system data rate was up to 180 kb/s using 16-QAM with ultrasonic channels from 55 to 99 kHz, over a line-of-sight transmission distance of 6 m with no detectable errors. The transmission range could be extended to 9 and 11 m using QPSK and BPSK modulation schemes, respectively. The achieved data rates for the QPSK and BPSK schemes were 90 and 45 kb/s using the same bandwidth. For the high- k ultrasonic transducers, a maximum data rate up to 800 kb/s with no measurable errors was achieved up to a range of 0.7 m. The attainable transmission ranges were increased to 1.1 and 1.2 m with data rates of 400 and 200 kb/s using QPSK and BPSK, respectively.

Mn-Doped CaBi4Ti4O15/Pb(Zr,Ti)O3 Ultrasonic Transducers for Continuous Monitoring at Elevated Temperatures

PubMed Central

Kibe, Taiga; Nagata, Hajime

2017-01-01

Continuous ultrasonic in-situ monitoring for industrial applications is difficult owing to the high operating temperatures in industrial fields. It is expected that ultrasonic transducers consisting of a CaBi4Ti4O15(CBT)/Pb(Zr,Ti)O3(PZT) sol-gel composite could be one solution for ultrasonic nondestructive testing (NDT) above 500 °C because no couplant is required and CBT has a high Curie temperature. To verify the high temperature durability, CBT/PZT sol-gel composite films were fabricated on titanium substrates by spray coating, and the CBT/PZT samples were tested in a furnace at various temperatures. Reflected echoes with a high signal-to-noise ratio were observed up to 600 °C. A thermal cycle test was conducted from room temperature to 600 °C, and no significant deterioration was found after the second thermal cycle. To investigate the long-term high-temperature durability, a CBT/PZT ultrasonic transducer was tested in the furnace at 600 °C for 36 h. Ultrasonic responses were recorded every 3 h, and the sensitivity and signal-to-noise ratio were stable throughout the experiment. PMID:29186910

Advance High Temperature Inspection Capabilities for Small Modular Reactors: Part 1 - Ultrasonics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bond, Leonard J.; Bowler, John R.

The project objective was to investigate the development non-destructive evaluation techniques for advanced small modular reactors (aSMR), where the research sought to provide key enabling inspection technologies needed to support the design and maintenance of reactor component performance. The project tasks for the development of inspection techniques to be applied to small modular reactor are being addressed through two related activities. The first is focused on high temperature ultrasonic transducers development (this report Part 1) and the second is focused on an advanced eddy current inspection capability (Part 2). For both inspection techniques the primary aim is to develop in-servicemore » inspection techniques that can be carried out under standby condition in a fast reactor at a temperature of approximately 250°C in the presence of liquid sodium. The piezoelectric material and the bonding between layers have been recognized as key factors fundamental for development of robust ultrasonic transducers. Dielectric constant characterization of bismuth scantanate-lead titanate ((1-x)BiScO 3-xPbTiO 3) (BS-PT) has shown a high Curie temperature in excess of 450°C , suitable for hot stand-by inspection in liquid metal reactors. High temperature pulse-echo contact measurements have been performed with BS-PT bonded to 12.5 mm thick 1018-low carbon steel plate from 20C up to 260 C. High temperature air-backed immersion transducers have been developed with BS-PT, high temperature epoxy and quarter wavlength nickel plate, needed for wetting ability in liquid sodium. Ultrasonic immersion measurements have been performed in water up to 92C and in silicone oil up to 140C. Physics based models have been validated with room temperature experimental data with benchmark artifical defects.« less

Recent Advances in the Development and Application of Power Plate Transducers in Dense Gas Extraction and Aerosol Agglomeration Processes

NASA Astrophysics Data System (ADS)

Riera, E.; Cardoni, A.; Gallego-Juárez, J. A.; Acosta, V. M.; Blanco, A.; Rodríguez, G.; Blasco, M.; Herranz, L. E.

Power ultrasound (PU) is an emerging, innovative, energy saving and environmental friendly technology that is generating a great interest in sectors such as food and pharmaceutical industries, green chemistry, environmental pollution, and other processes, where sustainable and energy efficient methods are required to improve and/or produce specific effects. Two typical effects of PU are the enhancement of mass transfer in gases and liquids, and the induction of particle agglomeration in aerosols. These effects are activated by a variety of mechanisms associated to the nonlinear propagation of high amplitude ultrasonic waves such as diffusion, agitation, entrainment, turbulence, etc. During the last years a great effort has been jointly made by the Spanish National Research Council (CSIC) and the company Pusonics towards introducing novel processes into the market based on airborne ultrasonic plate transducers. This technology was specifically developed for the treatment of gas and multiphasic media characterized by low specific acoustic impedance and high acoustic absorption. Different strategies have been developed to mitigate the effects of the nonlinear dynamic behavior of such ultrasonic piezoelectric transducers in order to enhance and stabilize their response at operational power conditions. This work deals with the latter advances in the mitigation of nonlinear problems found in power transducers; besides it describes two applications assisted by ultrasound developed at semi-industrial and laboratory scales and consisting in extraction via dense gases and particle agglomeration. Dense Gas Extraction (DGE) assisted by PU is a new process with a potential to enhance the extraction kinetics with supercritical CO2. Acoustic agglomeration of fine aerosol particles has a great potential for the treatment of air pollution problems generated by particulate materials. Experimental and numerical results in both processes will be shown and discussed.

Piezoelectric and Electrostatic Polymeric Transducers for Acoustic Emission Detection.

DTIC Science & Technology

1984-12-01

the fabrication of ultrasonic transducers for acoustic emission (A.E.) detection using polyvinylidene fluoride ( PVDF ) active elements. ii) the...characterization of PVDF transducers. The second report compared the sensitivity of PVDF transducers with polypropylene electrostatic transducer...detection using polyvinylidene 1uoride ( PVDF ) active elements. ii) the fabrication of electrostatic transducers using thin film of non-polar

Automated Guided-Wave Scanning Developed to Characterize Materials and Detect Defects

NASA Technical Reports Server (NTRS)

Martin, Richard E.; Gyekenyeski, Andrew L.; Roth, Don J.

2004-01-01

The Nondestructive Evaluation (NDE) Group of the Optical Instrumentation Technology Branch at the NASA Glenn Research Center has developed a scanning system that uses guided waves to characterize materials and detect defects. The technique uses two ultrasonic transducers to interrogate the condition of a material. The sending transducer introduces an ultrasonic pulse at a point on the surface of the specimen, and the receiving transducer detects the signal after it has passed through the material. The aim of the method is to correlate certain parameters in both the time and frequency domains of the detected waveform to characteristics of the material between the two transducers. The scanning system is shown. The waveform parameters of interest include the attenuation due to internal damping, waveform shape parameters, and frequency shifts due to material changes. For the most part, guided waves are used to gauge the damage state and defect growth of materials subjected to various mechanical or environmental loads. The technique has been applied to polymer matrix composites, ceramic matrix composites, and metal matrix composites as well as metallic alloys. Historically, guided wave analysis has been a point-by-point, manual technique with waveforms collected at discrete locations and postprocessed. Data collection and analysis of this type limits the amount of detail that can be obtained. Also, the manual movement of the sensors is prone to user error and is time consuming. The development of an automated guided-wave scanning system has allowed the method to be applied to a wide variety of materials in a consistent, repeatable manner. Experimental studies have been conducted to determine the repeatability of the system as well as compare the results obtained using more traditional NDE methods. The following screen capture shows guided-wave scan results for a ceramic matrix composite plate, including images for each of nine calculated parameters. The system can display up to 18 different wave parameters. Multiple scans of the test specimen demonstrated excellent repeatability in the measurement of all the guided-wave parameters, far exceeding the traditional point-by-point technique. In addition, the scan was able to detect a subsurface defect that was confirmed using flash thermography This technology is being further refined to provide a more robust and efficient software environment. Future hardware upgrades will allow for multiple receiving transducers and the ability to scan more complex surfaces. This work supports composite materials development and testing under the Ultra-Efficient Engine Technology (UEET) Project, but it also will be applied to other material systems under development for a wide range of applications.

Performance enhancement of an air-coupled multiple moving membrane capacitive micromachined ultrasonic transducer using an optimized middle plate configuration

NASA Astrophysics Data System (ADS)

Emadi, Arezoo; Buchanan, Douglas

2016-10-01

A multiple moving membrane capacitive micromachined ultrasonic transducer has been developed. This transducer cell structure includes a second flexible plate suspended between the transducer top plate and the fixed bottom electrode. The added plate influences the transducer top plate deflection map and, therefore, the transducer properties. Three series of individual air-coupled, dual deflectable plate transducers and two 1×27 element transducer arrays were fabricated using multiuser microelectromechanical systems (MEMS) processes (MUMPs). Each set of transducers included devices with middle plate radii from 22% to 65% of the corresponding transducer top plate radius. The effect of the transducer middle plate configuration has been investigated. Electrical, optical, and acoustic characterizations were conducted and the results were compared with the simulation findings. It was found that the transducer top plate amplitude of vibration is significantly enhanced with a wider middle deflectable plate. The electrical and optical measurement results are shown to be in good agreement with simulation results. The acoustic measurement results indicated a 37% increase in the amplitude of transmitted signal by the 1-MHz air-couple transducer when its middle plate radius was increased by 35%.

Detection of defects in red oak deckboards by ultrasonic scanning

Treesearch

Mohammed F. Kabir; Daniel L. Schmoldt; Mark E. Schafer

2000-01-01

Experiments were conducted to detect defects in red oak (Quercus rubra, L.) deckboards by ultrasonic scanning. Scanning of the deckboards was carried out with two rolling transducers in a pitch-catch arrangement with pallet parts moving between the transducers at 70 ft/m and 220 ft/m. Data were collected, stored and processed using LabViewTM software. The defects...

Advancements in NDE for utilities and the petrochemical industry through electromagnetic acoustic transducers (EMATs)

NASA Astrophysics Data System (ADS)

Robertson, M. O.; Stevens, Donald M.; Schlader, Daniel M.; Tilley, Richard M.

1998-03-01

The ultrasonic testing (UT) method continues to broaden in its effectiveness and capabilities for nondestructive evaluation (NDE). Much of this expansion can be attributed to advancements in specific techniques of the method. The utilization of electromagnetic acoustic transducers (EMATs) in dedicated ultrasonic systems has provided McDermott Technology, Inc. (MTI), formerly Babcock & Wilcox, with significant advantages over conventional ultrasonics. In recent years, through significant R&D, MTI has been instrumental in bringing about considerable advancements in the maturing EMAT technology. Progress in electronic design, magnet configurations, and sensor concepts has greatly improved system capabilities while reducing cost and equipment size. These improvements, coupled with the inherent advantages of utilizing the non-contact EMAT technique, have combined to make this technology a viable option for many commercial system inspection applications. MTI has recently completed the development and commercialization of an EMAT-based UT scanner for boiler tube thickness measurements. MTI is currently developing an automated EMAT scanner, based on phased array technology, for complete volumetric inspection of circumferential girth welds associated with pipelines (intended primarily for offshore applications). Additional benefits of phased array technology for providing materials characterization are currently being researched.

Improvement of range spatial resolution of medical ultrasound imaging by element-domain signal processing

NASA Astrophysics Data System (ADS)

Hasegawa, Hideyuki

2017-07-01

The range spatial resolution is an important factor determining the image quality in ultrasonic imaging. The range spatial resolution in ultrasonic imaging depends on the ultrasonic pulse length, which is determined by the mechanical response of the piezoelectric element in an ultrasonic probe. To improve the range spatial resolution without replacing the transducer element, in the present study, methods based on maximum likelihood (ML) estimation and multiple signal classification (MUSIC) were proposed. The proposed methods were applied to echo signals received by individual transducer elements in an ultrasonic probe. The basic experimental results showed that the axial half maximum of the echo from a string phantom was improved from 0.21 mm (conventional method) to 0.086 mm (ML) and 0.094 mm (MUSIC).

Directional nonlinear guided wave mixing: Case study of counter-propagating shear horizontal waves

NASA Astrophysics Data System (ADS)

Hasanian, Mostafa; Lissenden, Cliff J.

2018-04-01

While much nonlinear ultrasonics research has been conducted on higher harmonic generation, wave mixing provides the potential for sensitive measurements of incipient damage unencumbered by instrumentation nonlinearity. Studies of nonlinear ultrasonic wave mixing, both collinear and noncollinear, for bulk waves have shown the robust capability of wave mixing for early damage detection. One merit of bulk wave mixing lies in their non-dispersive nature, but guided waves enable inspection of otherwise inaccessible material and a variety of mixing options. Co-directional guided wave mixing was studied previously, but arbitrary direction guided wave mixing has not been addressed until recently. Wave vector analysis is applied to study variable mixing angles to find wave mode triplets (two primary waves and a secondary wave) resulting in the phase matching condition. As a case study, counter-propagating Shear Horizontal (SH) guided wave mixing is analyzed. SH wave interactions generate a secondary Lamb wave mode that is readily receivable. Reception of the secondary Lamb wave mode is compared for an angle beam transducer, an air coupled transducer, and a laser Doppler vibrometer (LDV). Results from the angle beam and air coupled transducers are quite consistent, while the LDV measurement is plagued by variability issues.

Ultrasonic input-output for transmitting and receiving longitudinal transducers coupled to same face of isotropic elastic plate

NASA Technical Reports Server (NTRS)

Williams, J. H., Jr.; Karagulle, H.; Lee, S. S.

1982-01-01

The quantitative understanding of ultrasonic nondestructive evaluation parameters such as the stress wave factor were studied. Ultrasonic input/output characteristics for an isotropic elastic plate with transmitting and receiving longitudinal transducers coupled to the same face were analyzed. The asymptotic normal stress is calculated for an isotropic elastic half space subjected to a uniform harmonic normal stress applied to a circular region at the surface. The radiated stress waves are traced within the plate by considering wave reflections at the top and bottom faces. The output voltage amplitude of the receiving transducer is estimated by considering only longitudinal waves. Agreement is found between the output voltage wave packet amplitudes and times of arrival due to multiple reflections of the longitudinal waves.

Real-time Monitoring Of Damage Evolution In Aerospace Materials Using Nonlinear Acoustics

NASA Astrophysics Data System (ADS)

Matikas, T. E.; Paipetis, A.; Kostopoulos, V.

2008-06-01

This work deals with the development of a novel non-destructive technique based on nonlinear acoustics, enabling real-time monitoring of material degradation in aerospace structures. When a sinusoidal ultrasonic wave of a given frequency and of sufficient amplitude is introduced into a nonlinear or an-harmonic solid, the fundamental wave distorts as it propagates, so that the second and higher harmonics of the fundamental frequency are generated. The measurement of the amplitude of these harmonics provides information on the coefficient of the second and higher order terms of the stress-strain relation for a nonlinear solid. It is demonstrated here that the material bulk nonlinear parameter for titanium alloy samples at different fatigue levels exhibits large changes compared to linear ultrasonic parameters such as velocity and attenuation. However, the use of bulk ultrasonic waves has serious disadvantages for the health monitoring of aerospace structures since it requires the placement of ultrasonic transducers on two, perfectly parallel, opposite sides of the samples. Such a setup is hardly feasible in real field conditions. For this reason, surface acoustic waves (SAW) were used in this study enabling the in-situ characterization of fatigue damage. The experimental setup for measuring the material nonlinear parameter using SAW was realised and the feasibility of the technique for health monitoring of aerospace structures was evaluated.

Acoustic levitation of a large solid sphere

NASA Astrophysics Data System (ADS)

Andrade, Marco A. B.; Bernassau, Anne L.; Adamowski, Julio C.

2016-07-01

We demonstrate that acoustic levitation can levitate spherical objects much larger than the acoustic wavelength in air. The acoustic levitation of an expanded polystyrene sphere of 50 mm in diameter, corresponding to 3.6 times the wavelength, is achieved by using three 25 kHz ultrasonic transducers arranged in a tripod fashion. In this configuration, a standing wave is created between the transducers and the sphere. The axial acoustic radiation force generated by each transducer on the sphere was modeled numerically as a function of the distance between the sphere and the transducer. The theoretical acoustic radiation force was verified experimentally in a setup consisting of an electronic scale and an ultrasonic transducer mounted on a motorized linear stage. The comparison between the numerical and experimental acoustic radiation forces presents a good agreement.

Split-mode ultrasonic transducer.

PubMed

Ostrovskii, Igor; Cremaldi, Lucien

2013-08-01

A split-mode ultrasonic transducer is investigated in both theory and experiment. This transducer is a two-dimensional structure of periodically poled domains in a ferroelectric wafer with free surfaces. The acoustic vibrations are excited by a radio frequency electric current applied along the length of the wafer, which allows the basal-plane surfaces to be free of metal coatings and thus ready for further biomedical applications. A specific physical property of this transducer consists of the multiple acousto-electric resonances, which occur due to an acoustic mode split when the acoustic half-wavelength is equal to the domain length. Possible applications include ultrasonic generation and detection at the micro-scale, intravascular sonification and visualization, ultrasound therapy of localized small areas such as the eye, biomedical applications for cell cultures, and traditional nondestructive testing including bones and tissues. A potential use of a non-metallized wafer is a therapeutic application with double action that is both ultrasound itself and an electric field over the wafer. The experimental measurements and theoretical calculations are in good agreement.

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dubey, P. K., E-mail: premkdubey@gmail.com; Kumar, Yudhisther; Gupta, Reeta

2014-05-15

The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occursmore » at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.« less

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

NASA Astrophysics Data System (ADS)

Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

2014-05-01

The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

Design of matching layers for high-frequency ultrasonic transducers

PubMed Central

Fei, Chunlong; Ma, Jianguo; Chiu, Chi Tat; Williams, Jay A.; Fong, Wayne; Chen, Zeyu; Zhu, BenPeng; Xiong, Rui; Shi, Jing; Hsiai, Tzung K.; Shung, K. Kirk; Zhou, Qifa

2015-01-01

Matching the acoustic impedance of high-frequency (≥100 MHz) ultrasound transducers to an aqueous loading medium remains a challenge for fabricating high-frequency transducers. The traditional matching layer design has been problematic to establish high matching performance given requirements on both specific acoustic impedance and precise thickness. Based on both mass-spring scheme and microwave matching network analysis, we interfaced metal-polymer layers for the matching effects. Both methods hold promises for guiding the metal-polymer matching layer design. A 100 MHz LiNbO3 transducer was fabricated to validate the performance of the both matching layer designs. In the pulse-echo experiment, the transducer echo amplitude increased by 84.4% and its −6dB bandwidth increased from 30.2% to 58.3% comparing to the non-matched condition, demonstrating that the matching layer design method is effective for developing high-frequency ultrasonic transducers. PMID:26445518

Finite element simulation and experimental verification of ultrasonic non-destructive inspection of defects in additively manufactured materials

NASA Astrophysics Data System (ADS)

Taheri, H.; Koester, L.; Bigelow, T.; Bond, L. J.

2018-04-01

Industrial applications of additively manufactured components are increasing quickly. Adequate quality control of the parts is necessary in ensuring safety when using these materials. Base material properties, surface conditions, as well as location and size of defects are some of the main targets for nondestructive evaluation of additively manufactured parts, and the problem of adequate characterization is compounded given the challenges of complex part geometry. Numerical modeling can allow the interplay of the various factors to be studied, which can lead to improved measurement design. This paper presents a finite element simulation verified by experimental results of ultrasonic waves scattering from flat bottom holes (FBH) in additive manufacturing materials. A focused beam immersion ultrasound transducer was used for both the modeling and simulations in the additive manufactured samples. The samples were SS17 4 PH steel samples made by laser sintering in a powder bed.

Analysis of Critically Refracted Longitudinal and Lamb Waves for Stress Characterization

NASA Astrophysics Data System (ADS)

Pei, Ning

The global production of metal, in particular, steel and aluminum keeps increasing. This material is used with various fabrication processes, such as, welding, forging, and rolling that can induce stresses in the material that can subsequently impact product performance and cause phenomena such as cracking and corrosion. When investigating plate materials it is necessary to map both texture and stress under a range of loading conditions. To address these needs a wide range of both destructive and nondestructive tools have been used. One family of methods are those based on ultrasonic measurements that relate ultrasonic velocity to properties, in particular stress. Two particular challenges are faced which are the relative insensitivity of compression and shear waves to stress and that there are also other factors which can also change velocity and these are temperature, texture and grain size. This project focused on an analysis of ultrasonic velocity measurements and specifically ways to improve performance and capabilities for stress characterization. Two approaches were considered and are reported: the critically refracted ultrasonic longitudinal (LCR) wave and higher order Lamb waves. The LCR wave method was modelled and optimized based on the fact that the sensitivity between waves and stress can reach maximum when they propagate in the same direction. However, in reality this wave typically propagates at an angle to stress, which will decrease its sensitivity. This thesis reports a numerical model used to investigate the transducers parameters that can influence the directivity of the LCR wave and hence enable performance optimization when used for industrial applications. An orthogonal test method is used to study the transducer parameters which influence the LCR wave beams and this method provides a design tool that can be used to study and optimize multiple parameter experiments and identify which parameter or parameters are of most significance. The example considered simulation of the acoustic field in a 2-D water-steel model is obtained using a Spatial Fourier Analysis method. The significance of the effects of incident angle, the aperture and the center frequency of the transducer were studied. Results show that the aperture, the center frequency and the incident angle are the most important factors in controlling the directivity of the resulting LCR wave fields.

A Labor and Delivery Patient Classification System Based on Direct Nursing Care Time

DTIC Science & Technology

1991-08-01

physician 2409 Internal or external monitoring--uterine contraction/ fetal heart tones 2410 Manual contraction assessment 2411 Pitocin induction...assisting physician 2412 Fetal heart tones, manual 2413 Fetal heart tones, doppler 2414 Fetal scalp sampling, assisting physician 241E Routine delivery room... heart tones, ultrasonic transducer 2437 Monitoring fetal heart tones, ultrasonic transducer and uterine contraction, tocotransducer 69 Appendix B: List

Pulse-Echo Ultrasonic Imaging Method for Eliminating Sample Thickness Variation Effects

NASA Technical Reports Server (NTRS)

Roth, Don J. (Inventor)

1997-01-01

A pulse-echo, immersion method for ultrasonic evaluation of a material which accounts for and eliminates nonlevelness in the equipment set-up and sample thickness variation effects employs a single transducer and automatic scanning and digital imaging to obtain an image of a property of the material, such as pore fraction. The nonlevelness and thickness variation effects are accounted for by pre-scan adjustments of the time window to insure that the echoes received at each scan point are gated in the center of the window. This information is input into the scan file so that, during the automatic scanning for the material evaluation, each received echo is centered in its time window. A cross-correlation function calculates the velocity at each scan point, which is then proportionalized to a color or grey scale and displayed on a video screen.

Structural model of standard ultrasonic transducer array developed for FEM analysis of mechanical crosstalk.

PubMed

Celmer, M; Opieliński, K J; Dopierała, M

2018-02-01

One of the reasons of distortions in ultrasonic imaging are crosstalk effects. They can be divided into groups according to the way of their formation. One of them is constituted by mechanical crosstalk, which is propagated by a construction of a multi-element array of piezoelectric transducers. When an individual transducer is excited, mechanical vibrations are transferred to adjacent construction components, thereby stimulating neighboring transducers to an undesired operation. In order to explore ways of the propagation of such vibrations, the authors developed the FEM model of the array of piezoelectric transducers designed for calculations in COMSOL Multiphysics software. Simulations of activating individual transducers and calculated electrical voltages appearing on transducers unstimulated intentionally, were performed in the time domain in order to assess the propagation velocity of different vibration modes through the construction elements. On this basis, conclusions were drawn in terms of the participation of various construction parts of the array of piezoelectric transducers in the process of creating the mechanical crosstalk. The elaborated FEM model allowed also to examine the ways aimed at reducing the transmission of mechanical crosstalk vibrations through the components of the array. Studies showed that correct cuts in the fasteners and the front layer improve the reduction of the mechanical crosstalk effect. The model can become a helpful tool in the process of design and modifications of manufactured ultrasonic arrays particularly in terms of mechanical crosstalk reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

The Effect of Fabric Position to the Distribution of Acoustic Pressure Field in Ultrasonic Bath

NASA Astrophysics Data System (ADS)

Gürses, B. O.; Özdemir, A. O.; Tonay, Ö.; Şener, M.; Perinçek, S.

2017-10-01

Nowadays, the use of ultrasonic energy in textile wet processes at industrial-scale is limited. It is largely due to the lack of understanding about design, operational and performance characteristics of the ultrasonic bath, suitable for textile treatments. In the context of this study, the effect of fabric position, as one of the design parameter, to the distribution of acoustic pressure field in ultrasonic bath was investigated. The ultrasonic bath in the size 20×30 cm2 with one transducer at frequency 40 kHz was used in experiments. The cotton fabric with 1 mm thickness was moved along vertical and horizontal directions of the ultrasonic bath. The acoustic field and cavitation volume density in the bath is analyzed by COMSOL Multiphysic. The cavitation volume density is calculated by comparing the pressure points in the bath with cavitation threshold pressure. Consequently, it was found that the position of the textile material in the ultrasonic bath is one of the most important factors to achieve the uniform and maximum acoustic cavitation field. So, it should be taken into consideration during the design of industrial-scale ultrasonic bath used in textile wet processes.

Determination of physical and dynamic properties of suspended particles in water column with ultrasonic scanning in between the water surface and stable sediment layer.

NASA Astrophysics Data System (ADS)

Acar, Dursun; Alpar, Bedri; Ozeren, Sinan; Cagatay, Namık; Sari, Erol; Vardar, Denizhan; Eris, Kadir

2015-04-01

The behavior of seafloor sediment with its water column should be known against any occurrences of anoxic or oxic conditions. The most important ones of these conditions are possible leakage of natural gas or escape of liquids from sediment. On the basis of combined solid/liquid flow dynamics in sedimentation, such kind of events can change, even in an effective manner, the dynamic movements of molecules and their cumulative mass of particules, i.e. the suspended materials. The deployment of suitable sediment traps or ultrasonic transducers somewhere in the water column are not easy attempts in order to obtain useful information about the state of suspended materials during sedimentation. These are usually bulky instruments; therefore they may behave like an anti-move suppresser on the particles moving in the float direction, in oxic and anoxic manner. These instruments, on the other hand, may cover the effects of diffusive flow or bubble formed gas and fluid escape from the sediment surface into the water column. Ultrasonic scanners, however, are able to make observations in a remote manner, without affecting such artificial events. Our field trials were successfully completed at the historical estuary called Halic of Marmara sea . The physical properties; such as the velocity of particles, their travel directions, their dimensions and the ability to observe anti-compositor crushes of shock waves of the bubbles are only a few of these observations in natural ambience. The most important problem solved about water pressure during 3 atmosphere . The sensor has been tested successfully few times. We used the ''High voltage electric isolator oil filling'' to the inside of the scanner for pressure equalization between outer side and inner body of probe at a depth of (20 meters) beneath the sea surface . The transmitted signals by the planar crystal of the transducer become weaker under the pressure of overlying water column in depths. Our efforts are now focused on the improved performance of transducer at higher than over 3 atm pressure. Keywords: ultrasonic , flow , particle , Sediment , Cumulative mass

Practical ultrasonic transducers for high-temperature applications using bismuth titanate and Ceramabind 830

NASA Astrophysics Data System (ADS)

Xu, Janet L.; Batista, Caio F. G.; Tittmann, Bernhard R.

2018-04-01

Structural health monitoring of large valve bodies in high-temperature environments such as power plants faces several limitations: commercial transducers are not rated for such high temperatures, gel couplants will evaporate, and measurements cannot be made in-situ. To solve this, we have furthered the work of Ledford in applying a practical transducer in liquid form which hardens and air dries directly onto the substrate. The transducer material is a piezoceramic film composed of bismuth titanate and a high-temperature binding agent, Ceramabind 830. The effects of several fabrication conditions were studied to optimize transducer performance and ensure repeatability. These fabrication conditions include humidity, binder ratio, water ratio, substrate roughness, and film thickness. The final product is stable for both reactive and non-reactive substrates, has a quick fabrication time, and has an operating temperature up to the Curie temperature of BIT, 650°C, well beyond the safe operating temperature of PZT (150°C).

Sound controlled rotation of a cluster of small particles on an ultrasonically vibrating metal strip

NASA Astrophysics Data System (ADS)

Zhang, Xueyi; Zheng, Yun; Hu, Junhui

2008-01-01

We show that a vibrating metal strip, mechanically driven by an ultrasonic transducer, can rotate a cluster of small particles around a fixed point, and the diameter of the cluster of small particles can reach a stable value (steady diameter) for a given driving condition. The rotation is very stable when the vibration of the metal strip is appropriate. The revolution speed, its direction, and steady diameter of the particle cluster can be controlled by the operating frequency of the ultrasonic transducer. For shrimp eggs, a revolution speed up to 360rpm can be obtained.

Coupling apparatus for ultrasonic medical diagnostic system

NASA Technical Reports Server (NTRS)

Frazer, R. E. (Inventor)

1978-01-01

An apparatus for the ultrasonic scanning of a breast or other tissue is reported that contains a cavity for receiving the breast, a vacuum for drawing the breast into intimate contact with the walls of the cavity, and transducers coupled through a fluid to the cavity to transmit sound waves through the breast. Each transducer lies at the end of a tapered chamber which has flexible walls and which is filled with fluid, so that the transducer can be moved in a raster pattern while the chamber walls flex accordingly, with sound transmission always occurring through the fluid.

High frequency copolymer ultrasonic transducer array of size-effective elements

NASA Astrophysics Data System (ADS)

Decharat, Adit; Wagle, Sanat; Habib, Anowarul; Jacobsen, Svein; Melandsø, Frank

2018-02-01

A layer-by-layer deposition method for producing dual-layer ultrasonic transducers from piezoelectric copolymers has been developed. The method uses a combination of customized and standard processing to obtain 2D array transducers with electrical connection of the individual elements routed directly to the rear of the substrate. A numerical model was implemented to study basic parameters effecting the transducer characteristics. Key elements of the array were characterized and evaluated, demonstrating its viability of 2D imaging. Signal reproducibility of the prototype array was studied by characterizing the variations of the center frequency (≈42 MHz) and bandwidth (≈25 MHz) of the acoustic. Object identification was also tested and parameterized by acoustic-field beamwidth as well as proper scan step size. Simple tests to illustrate a benefit of multi-element scan on lowering the inspection time were conducted. Structural imaging of the test structure underneath multi-layered wave media (glass plate and distilled water) was also performed. The prototype presented in this work is an important step towards realizing an inexpensive, compact array of individually operated copolymer transducers that can serve in a fast/volumetric high frequency (HF) ultrasonic scanning platform.

Ultrasonic dip seal maintenance system

DOEpatents

Poindexter, Allan M.; Ricks, Herbert E.

1978-01-01

A system for removing impurities from the surfaces of liquid dip seals and or wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities.

Acoustic levitation of a large solid sphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrade, Marco A. B., E-mail: marcobrizzotti@gmail.com; Bernassau, Anne L.; Adamowski, Julio C.

2016-07-25

We demonstrate that acoustic levitation can levitate spherical objects much larger than the acoustic wavelength in air. The acoustic levitation of an expanded polystyrene sphere of 50 mm in diameter, corresponding to 3.6 times the wavelength, is achieved by using three 25 kHz ultrasonic transducers arranged in a tripod fashion. In this configuration, a standing wave is created between the transducers and the sphere. The axial acoustic radiation force generated by each transducer on the sphere was modeled numerically as a function of the distance between the sphere and the transducer. The theoretical acoustic radiation force was verified experimentally in a setupmore » consisting of an electronic scale and an ultrasonic transducer mounted on a motorized linear stage. The comparison between the numerical and experimental acoustic radiation forces presents a good agreement.« less

Degree of dispersion monitoring by ultrasonic transmission technique and excitation of the transducer's harmonics

NASA Astrophysics Data System (ADS)

Schober, G.; Heidemeyer, P.; Kretschmer, K.; Bastian, M.; Hochrein, T.

2014-05-01

The degree of dispersion of filled polymer compounds is an important quality parameter for various applications. For instance, there is an influence on the chroma in pigment colored plastics or on the mechanical properties of filled or reinforced compounds. Most of the commonly used offline methods are work-intensive and time-consuming. Moreover, they do not allow an all-over process monitoring. In contrast, the ultrasonic technique represents a suitable robust and process-capable inline method. Here, we present inline ultrasonic measurements on polymer melts with a fundamental frequency of 1 MHz during compounding. In order to extend the frequency range we additionally excite the fundamental and the odd harmonics vibrations at 3 and 5 MHz. The measurements were carried out on a compound consisting of polypropylene and calcium carbonate. For the simulation of agglomerates calcium carbonate with a larger particle size was added with various rates. The total filler content was kept constant. The frequency selective analysis shows a linear correlation between the normalized extinction and the rate of agglomerates simulated by the coarser filler. Further experiments with different types of glass beads with a well-defined particle size verify these results. A clear correlation between the normalized extinction and the glass bead size as well as a higher damping with increasing frequency corresponds to the theoretical assumption. In summary the dispersion quality can be monitored inline by the ultrasonic technique. The excitation of the ultrasonic transducer's harmonics generates more information about the material as the usage of the pure harmonic vibration.

The development of recent high-power ultrasonic transducers for Near-well ultrasonic processing technology.

PubMed

Wang, Zhenjun; Xu, Yuanming

2017-07-01

With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology. With the reduction of crude oil throughout the world, enhance oil recovery technology has become a major oil research topics, which can greatly increase the recovery ratio of the crude oil before the dawning of renewable energy era. Near-well ultrasonic processing technology, as one new method, has attracted more attention for Enhanced Oil Recovery due to its low cost, good applicability and no environmental pollution in recent rears. There are two important relevant aspects about Near-well ultrasonic processing technology: (a) how to enhance the oil flow through the rocks into the pumping pool and (b) how to reduce the oil viscosity so that it can be easier to pump. Therefore, how to design a high-power ultrasonic equipment with excellent performance is crucial for Near-well ultrasonic processing technology. In this paper, recent new high-power ultrasonic transducers for Near-well ultrasonic processing technology are summarized. Each field application of them are also given. The purpose of this paper is to provide reference for the further development of Near-well ultrasonic processing technology. Copyright © 2017 Elsevier B.V. All rights reserved.

Non-contact thermoacoustic detection of embedded targets using airborne-capacitive micromachined ultrasonic transducers

NASA Astrophysics Data System (ADS)

Nan, Hao; Boyle, Kevin C.; Apte, Nikhil; Aliroteh, Miaad S.; Bhuyan, Anshuman; Nikoozadeh, Amin; Khuri-Yakub, Butrus T.; Arbabian, Amin

2015-02-01

A radio frequency (RF)/ultrasound hybrid imaging system using airborne capacitive micromachined ultrasonic transducers (CMUTs) is proposed for the remote detection of embedded objects in highly dispersive media (e.g., water, soil, and tissue). RF excitation provides permittivity contrast, and ultra-sensitive airborne-ultrasound detection measures thermoacoustic-generated acoustic waves that initiate at the boundaries of the embedded target, go through the medium-air interface, and finally reach the transducer. Vented wideband CMUTs interface to 0.18 μm CMOS low-noise amplifiers to provide displacement detection sensitivity of 1.3 pm at the transducer surface. The carefully designed vented CMUT structure provides a fractional bandwidth of 3.5% utilizing the squeeze-film damping of the air in the cavity.

Linear array transducer for high-power airborne ultrasound using flextensional structure

NASA Astrophysics Data System (ADS)

Yamamoto, Jun; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

2015-07-01

To change the direction of ultrasonic irradiation without moving a transducer, a high-power airborne ultrasonic transducer for a one-dimensional phased array system was designed and tested. A flextensional element transducer with higher-mode bending vibration was fabricated to obtain a high vibration amplitude over a wide aperture, where a phase-compensating stepped structure was employed. The width of the main lobe at half maximum and the sidelobe level were measured to be 14.3 deg and 0.78, respectively. The maximal sound pressure of 132 dB (0 dB re. 0.02 mPa) was obtained under the applied voltage of 4.0 V. The beam steering characteristics of a phased array using eight elements were compared with the simple theory.

Compact air scrubber

DOEpatents

Bentley, Bill F.; Jett, James H.; Martin, John C.; Saunders, George C.

1992-01-01

Method and apparatus for removing material from a gas. A mist created by a piezoelectric ultrasonic transducer is contacted with the gas and both gas and mist are passed through baffled separators. Liquid effluent from the separators contains solid material removed from the gas and gaseous material which reacted with the liquid or was absorbed by the liquid. The invention is useful for collecting a sample of material in a gas, such as a vapor in the atmosphere, and in cleaning a gas. A relatively concentrated solution of a material present in a gas in a very small concentration can be obtained.

Photoacoustic microscopic imaging of surface and subsurface damages in CFRP

NASA Astrophysics Data System (ADS)

Nakahata, Kazuyuki; Ogi, Keiji; Namita, Takeshi; Ohira, Katsumi; Maruyama, Masayuki; Shiina, Tsuyoshi

2018-04-01

Photoacoustic imaging comprises an optical excitation within a target zone and the detection of the ultrasonic wave so created. A pulsed laser illuminates the target zone, and this illumination causes rapid thermoelastic expansion that generates a broadband high-frequency ultrasonic wave (photoacoustic wave, PA). In this paper, we report proof-of-concept experiments for nondestructive testing of laminar materials using a PA microscope. A specimen containing carbon-fiber-reinforced plastic (CFRP) was used in this experiment and involved an artificial delamination. A 532-nm-wavelength laser irradiates the top surface of the specimen, and the resulting ultrasonic waves are received by a point-focusing immersion transducer on the same side. Our system estimated the depth and dimension of the subsurface delamination accurately. By coating a light-absorbing material on the surface, the amplitude of the PA wave increased. This finding shows that the signal-noise (S/N) ratio of the scattered wave from delaminations can be improved with the surface coatings.

Novel PMN-PT free standing film for high frequency (80MHz) intravascular ultrasonic imaging

PubMed Central

Li, Xiang; Zhou, Qifa; Shung, K. Kirk; Shih, Wei-Heng; Shih, Wan Y.

2011-01-01

[Pb(Mg1/3Nb2/3)O3]0.63[PbTiO3]0.37 (PMN-PT) free standing film of comparable piezoelectric property to bulk PMN-PT with a thickness of 33 μm has been fabricated using a modified precursor coating approach. At 1 KHz, the dielectric constant and loss were 4,160 and 0.0291, respectively. The remnant polarization and coercive field were 28 μC/cm2 and 18.43 kV/cm. The electromechanical coupling coefficient kt was measured to be 0.55, which was close to that of bulk PMN-PT single crystal material. A high frequency (80 MHz) miniature ultrasonic transducer with high sensitivity was fabricated from this film. In vitro imaging of a rabbit aorta was performed to demonstrate the application of this material to intravascular ultrasound imaging at 80 MHz. Compared to a 35 MHz ultrasonic image, the 80 MHz image showed superior resolution and contrast. PMID:22083761

Ultrasonic Determination of the Elastic Constants of Epoxy-natural Fiber Composites

NASA Astrophysics Data System (ADS)

Valencia, C. A. Meza; Pazos-Ospina, J. F.; Franco, E. E.; Ealo, Joao L.; Collazos-Burbano, D. A.; Garcia, G. F. Casanova

This paper shows the applications ultrasonic through-transmission technique to determine the elastic constants of two polymer-natural fiber composite materials with potential industrial application and economic and environmental advantages. The transversely isotropic coconut-epoxy and fique-epoxy samples were analyzed using an experimental setup which allows the sample to be rotated with respect to transducers faces and measures the time-of-flight at different angles of incidence. Then, the elastic properties of the material were obtained by fitting the experimental data to the Christoffel equation. Results show a good agreement between the measured elastic constants and the values predicted by an analytical model. The velocities as a function of the incidence angle are reported and the effect of the natural fiber on the stiffness of the composite is discussed.

Structural Health Monitoring of Above-Ground Storage Tank Floors by Ultrasonic Guided Wave Excitation on the Tank Wall.

PubMed

Lowe, Premesh S; Duan, Wenbo; Kanfoud, Jamil; Gan, Tat-Hean

2017-11-04

There is an increasing interest in using ultrasonic guided waves to assess the structural degradation of above-ground storage tank floors. This is a non-invasive and economically viable means of assessing structural degradation. Above-ground storage tank floors are ageing assets which need to be inspected periodically to avoid structural failure. At present, normal-stress type transducers are bonded to the tank annular chime to generate a force field in the thickness direction of the floor and excite fundamental symmetric and asymmetric Lamb modes. However, the majority of above-ground storage tanks in use have no annular chime due to a simplified design and/or have a degraded chime due to corrosion. This means that transducers cannot be mounted on the chime to assess structural health according to the present technology, and the market share of structural health monitoring of above-ground storage tank floors using ultrasonic guided wave is thus limited. Therefore, the present study investigates the potential of using the tank wall to bond the transducer instead of the tank annular chime. Both normal and shear type transducers were investigated numerically, and results were validated using a 4.1 m diameter above-ground storage tank. The study results show shear mode type transducers bonded to the tank wall can be used to assess the structural health of the above-ground tank floors using an ultrasonic guided wave. It is also shown that for the cases studied there is a 7.4 dB signal-to-noise ratio improvement at 45 kHz for the guided wave excitation on the tank wall using shear mode transducers.

Structural Health Monitoring of Above-Ground Storage Tank Floors by Ultrasonic Guided Wave Excitation on the Tank Wall

PubMed Central

Kanfoud, Jamil; Gan, Tat-Hean

2017-01-01

There is an increasing interest in using ultrasonic guided waves to assess the structural degradation of above-ground storage tank floors. This is a non-invasive and economically viable means of assessing structural degradation. Above-ground storage tank floors are ageing assets which need to be inspected periodically to avoid structural failure. At present, normal-stress type transducers are bonded to the tank annular chime to generate a force field in the thickness direction of the floor and excite fundamental symmetric and asymmetric Lamb modes. However, the majority of above-ground storage tanks in use have no annular chime due to a simplified design and/or have a degraded chime due to corrosion. This means that transducers cannot be mounted on the chime to assess structural health according to the present technology, and the market share of structural health monitoring of above-ground storage tank floors using ultrasonic guided wave is thus limited. Therefore, the present study investigates the potential of using the tank wall to bond the transducer instead of the tank annular chime. Both normal and shear type transducers were investigated numerically, and results were validated using a 4.1 m diameter above-ground storage tank. The study results show shear mode type transducers bonded to the tank wall can be used to assess the structural health of the above-ground tank floors using an ultrasonic guided wave. It is also shown that for the cases studied there is a 7.4 dB signal-to-noise ratio improvement at 45 kHz for the guided wave excitation on the tank wall using shear mode transducers. PMID:29113058

Design optimization of embedded ultrasonic transducers for concrete structures assessment.

PubMed

Dumoulin, Cédric; Deraemaeker, Arnaud

2017-08-01

In the last decades, the field of structural health monitoring and damage detection has been intensively explored. Active vibration techniques allow to excite structures at high frequency vibrations which are sensitive to small damage. Piezoelectric PZT transducers are perfect candidates for such testing due to their small size, low cost and large bandwidth. Current ultrasonic systems are based on external piezoelectric transducers which need to be placed on two faces of the concrete specimen. The limited accessibility of in-service structures makes such an arrangement often impractical. An alternative is to embed permanently low-cost transducers inside the structure. Such types of transducers have been applied successfully for the in-situ estimation of the P-wave velocity in fresh concrete, and for crack monitoring. Up to now, the design of such transducers was essentially based on trial and error, or in a few cases, on the limitation of the acoustic impedance mismatch between the PZT and concrete. In the present study, we explore the working principles of embedded piezoelectric transducers which are found to be significantly different from external transducers. One of the major challenges concerning embedded transducers is to produce very low cost transducers. We show that a practical way to achieve this imperative is to consider the radial mode of actuation of bulk PZT elements. This is done by developing a simple finite element model of a piezoelectric transducer embedded in an infinite medium. The model is coupled with a multi-objective genetic algorithm which is used to design specific ultrasonic embedded transducers both for hard and fresh concrete monitoring. The results show the efficiency of the approach and a few designs are proposed which are optimal for hard concrete, fresh concrete, or both, in a given frequency band of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

Confocal acoustic radiation force optical coherence elastography using a ring ultrasonic transducer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qi, Wenjuan; Department of Chemical Engineering and Materials Science, University of California, Irvine, Irvine, California 92697; Li, Rui

2014-03-24

We designed and developed a confocal acoustic radiation force optical coherence elastography system. A ring ultrasound transducer was used to achieve reflection mode excitation and generate an oscillating acoustic radiation force in order to generate displacements within the tissue, which were detected using the phase-resolved optical coherence elastography method. Both phantom and human tissue tests indicate that this system is able to sense the stiffness difference of samples and quantitatively map the elastic property of materials. Our confocal setup promises a great potential for point by point elastic imaging in vivo and differentiation of diseased tissues from normal tissue.

A Fast Method to Calculate the Spatial Impulse Response for 1-D Linear Ultrasonic Phased Array Transducers

PubMed Central

Zou, Cheng; Sun, Zhenguo; Cai, Dong; Muhammad, Salman; Zhang, Wenzeng; Chen, Qiang

2016-01-01

A method is developed to accurately determine the spatial impulse response at the specifically discretized observation points in the radiated field of 1-D linear ultrasonic phased array transducers with great efficiency. In contrast, the previously adopted solutions only optimize the calculation procedure for a single rectangular transducer and required approximation considerations or nonlinear calculation. In this research, an algorithm that follows an alternative approach to expedite the calculation of the spatial impulse response of a rectangular linear array is presented. The key assumption for this algorithm is that the transducer apertures are identical and linearly distributed on an infinite rigid plane baffled with the same pitch. Two points in the observation field, which have the same position relative to two transducer apertures, share the same spatial impulse response that contributed from corresponding transducer, respectively. The observation field is discretized specifically to meet the relationship of equality. The analytical expressions of the proposed algorithm, based on the specific selection of the observation points, are derived to remove redundant calculations. In order to measure the proposed methodology, the simulation results obtained from the proposed method and the classical summation method are compared. The outcomes demonstrate that the proposed strategy can speed up the calculation procedure since it accelerates the speed-up ratio which relies upon the number of discrete points and the number of the array transducers. This development will be valuable in the development of advanced and faster linear ultrasonic phased array systems. PMID:27834799

Method and apparatus for ultrasonic characterization through the thickness direction of a moving web

DOEpatents

Jackson, Theodore; Hall, Maclin S.

2001-01-01

A method and apparatus for determining the caliper and/or the ultrasonic transit time through the thickness direction of a moving web of material using ultrasonic pulses generated by a rotatable wheel ultrasound apparatus. The apparatus includes a first liquid-filled tire and either a second liquid-filled tire forming a nip or a rotatable cylinder that supports a thin moving web of material such as a moving web of paper and forms a nip with the first liquid-filled tire. The components of ultrasonic transit time through the tires and fluid held within the tires may be resolved and separately employed to determine the separate contributions of the two tire thicknesses and the two fluid paths to the total path length that lies between two ultrasonic transducer surfaces contained within the tires in support of caliper measurements. The present invention provides the benefit of obtaining a transit time and caliper measurement at any point in time as a specimen passes through the nip of rotating tires and eliminates inaccuracies arising from nonuniform tire circumferential thickness by accurately retaining point-to-point specimen transit time and caliper variation information, rather than an average obtained through one or more tire rotations. Morever, ultrasonic transit time through the thickness direction of a moving web may be determined independent of small variations in the wheel axle spacing, tire thickness, and liquid and tire temperatures.

Sand/cement ratio evaluation on mortar using neural networks and ultrasonic transmission inspection.

PubMed

Molero, M; Segura, I; Izquierdo, M A G; Fuente, J V; Anaya, J J

2009-02-01

The quality and degradation state of building materials can be determined by nondestructive testing (NDT). These materials are composed of a cementitious matrix and particles or fragments of aggregates. Sand/cement ratio (s/c) provides the final material quality; however, the sand content can mask the matrix properties in a nondestructive measurement. Therefore, s/c ratio estimation is needed in nondestructive characterization of cementitious materials. In this study, a methodology to classify the sand content in mortar is presented. The methodology is based on ultrasonic transmission inspection, data reduction, and features extraction by principal components analysis (PCA), and neural network classification. This evaluation is carried out with several mortar samples, which were made while taking into account different cement types and s/c ratios. The estimated s/c ratio is determined by ultrasonic spectral attenuation with three different broadband transducers (0.5, 1, and 2 MHz). Statistical PCA to reduce the dimension of the captured traces has been applied. Feed-forward neural networks (NNs) are trained using principal components (PCs) and their outputs are used to display the estimated s/c ratios in false color images, showing the s/c ratio distribution of the mortar samples.

Partial Discharge Ultrasound Detection Using the Sagnac Interferometer System

PubMed Central

Li, Xiaomin; Gao, Yan; Zhang, Hongjuan; Wang, Dong; Jin, Baoquan

2018-01-01

Partial discharge detection is crucial for electrical cable safety evaluation. The ultrasonic signals frequently generated in the partial discharge process contains important characteristic information. However, traditional ultrasonic transducers are easily subject to strong electromagnetic interference in environments with high voltages and strong magnetic fields. In order to overcome this problem, an optical fiber Sagnac interferometer system is proposed for partial discharge ultrasound detection. Optical fiber sensing and time-frequency analysis of the ultrasonic signals excited by the piezoelectric ultrasonic transducer is realized for the first time. The effective frequency band of the Sagnac interferometer system was up to 175 kHz with the help of a designed 10 kV partial discharge simulator device. Using the cumulative histogram method, the characteristic ultrasonic frequency band of the partial discharges was between 28.9 kHz and 57.6 kHz for this optical fiber partial discharge detection system. This new ultrasound sensor can be used as an ideal ultrasonic source for the intrinsically safe detection of partial discharges in an explosive environment. PMID:29734682

A study of space shuttle structural integrity test and assessment. Part 1

NASA Technical Reports Server (NTRS)

Anderson, R. E.; Poe, R. G.

1972-01-01

The ultrasonics technique for assessing the structural integrity of the primary surface of the space shuttle vehicles is discussed and evaluated. Analysis was made of transducers, transducer coupling test structure fabrication, flaws, and ultrasonic testing. Graphs of microphone response curves from the initial noise tests, accelerometer response curves from the final noise tests, and microphone curves from the final noise tests are included along with a glossary, bibliography, and results.

Quantitative ultrasonic evaluation of concrete structures using one-sided access

NASA Astrophysics Data System (ADS)

Khazanovich, Lev; Hoegh, Kyle

2016-02-01

Nondestructive diagnostics of concrete structures is an important and challenging problem. A recent introduction of array ultrasonic dry point contact transducer systems offers opportunities for quantitative assessment of the subsurface condition of concrete structures, including detection of defects and inclusions. The methods described in this paper are developed for signal interpretation of shear wave impulse response time histories from multiple fixed distance transducer pairs in a self-contained ultrasonic linear array. This included generalizing Kirchoff migration-based synthetic aperture focusing technique (SAFT) reconstruction methods to handle the spatially diverse transducer pair locations, creating expanded virtual arrays with associated reconstruction methods, and creating automated reconstruction interpretation methods for reinforcement detection and stochastic flaw detection. Interpretation of the reconstruction techniques developed in this study were validated using the results of laboratory and field forensic studies. Applicability of the developed methods for solving practical engineering problems was demonstrated.

A novel ultrasonic phased array inspection system to NDT for offshore platform structures

NASA Astrophysics Data System (ADS)

Wang, Hua; Shan, Baohua; Wang, Xin; Ou, Jinping

2007-01-01

A novel ultrasonic phased array detection system is developed for nondestructive testing (NDT). The purpose of the system is to make acquisition of data in real-time from 64-element ultrasonic phased array transducer, and to enable real- time processing of the acquired data. The system is composed of five main parts: master unit, main board, eight transmit/receive units, a 64-element transducer and an external PC. The system can be used with 64 element transducers, excite 32 elements, receive and sample echo signals form 32 elements simultaneously at 62.5MHz with 8 bit precision. The external PC is used as the user interface showing the real time images and controls overall operation of the system through USB serial link. The use of Universal Serial Bus (USB) improves the transform speed and reduces hardware interface complexity. The program of the system is written in Visual C++.NET and is platform independent.

Crack orientation and depth estimation in a low-pressure turbine disc using a phased array ultrasonic transducer and an artificial neural network.

PubMed

Yang, Xiaoxia; Chen, Shili; Jin, Shijiu; Chang, Wenshuang

2013-09-13

Stress corrosion cracks (SCC) in low-pressure steam turbine discs are serious hidden dangers to production safety in the power plants, and knowing the orientation and depth of the initial cracks is essential for the evaluation of the crack growth rate, propagation direction and working life of the turbine disc. In this paper, a method based on phased array ultrasonic transducer and artificial neural network (ANN), is proposed to estimate both the depth and orientation of initial cracks in the turbine discs. Echo signals from cracks with different depths and orientations were collected by a phased array ultrasonic transducer, and the feature vectors were extracted by wavelet packet, fractal technology and peak amplitude methods. The radial basis function (RBF) neural network was investigated and used in this application. The final results demonstrated that the method presented was efficient in crack estimation tasks.

Crack Orientation and Depth Estimation in a Low-Pressure Turbine Disc Using a Phased Array Ultrasonic Transducer and an Artificial Neural Network

PubMed Central

Yang, Xiaoxia; Chen, Shili; Jin, Shijiu; Chang, Wenshuang

2013-01-01

Stress corrosion cracks (SCC) in low-pressure steam turbine discs are serious hidden dangers to production safety in the power plants, and knowing the orientation and depth of the initial cracks is essential for the evaluation of the crack growth rate, propagation direction and working life of the turbine disc. In this paper, a method based on phased array ultrasonic transducer and artificial neural network (ANN), is proposed to estimate both the depth and orientation of initial cracks in the turbine discs. Echo signals from cracks with different depths and orientations were collected by a phased array ultrasonic transducer, and the feature vectors were extracted by wavelet packet, fractal technology and peak amplitude methods. The radial basis function (RBF) neural network was investigated and used in this application. The final results demonstrated that the method presented was efficient in crack estimation tasks. PMID:24064602

Pulse-echo ultrasonic imaging method for eliminating sample thickness variation effects

NASA Technical Reports Server (NTRS)

Roth, Don J. (Inventor)

1995-01-01

A pulse-echo, immersion method for ultrasonic evaluation of a material is discussed. It accounts for and eliminates nonlevelness in the equipment set-up and sample thickness variation effects employs a single transducer, automatic scanning and digital imaging to obtain an image of a property of the material, such as pore fraction. The nonlevelness and thickness variation effects are accounted for by pre-scan adjusments of the time window to insure that the echoes received at each scan point are gated in the center of the window. This information is input into the scan file so that, during the automatic scanning for the material evaluation, each received echo is centered in its time window. A cross-correlation function calculates the velocity at each scan point, which is then proportionalized to a color or grey scale and displayed on a video screen.

Effect of ultrasonic agitation on push-out bond strength and adaptation of root-end filling materials

PubMed Central

2018-01-01

Objectives This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. Materials and Methods Sixty maxillary canines were divided into 6 groups (n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. Results Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA (p < 0.05). US improved the push-out bond strength for all the cements (p < 0.05). Conclusions The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested. PMID:29765903

Measurement of material nonlinearity using surface acoustic wave parametric interaction and laser ultrasonics.

PubMed

Stratoudaki, Theodosia; Ellwood, Robert; Sharples, Steve; Clark, Matthew; Somekh, Michael G; Collison, Ian J

2011-04-01

A dual frequency mixing technique has been developed for measuring velocity changes caused by material nonlinearity. The technique is based on the parametric interaction between two surface acoustic waves (SAWs): The low frequency pump SAW generated by a transducer and the high frequency probe SAW generated and detected using laser ultrasonics. The pump SAW stresses the material under the probe SAW. The stress (typically <5 MPa) is controlled by varying the timing between the pump and probe waves. The nonlinear interaction is measured as a phase modulation of the probe SAW and equated to a velocity change. The velocity-stress relationship is used as a measure of material nonlinearity. Experiments were conducted to observe the pump-probe interaction by changing the pump frequency and compare the nonlinear response of aluminum and fused silica. Experiments showed these two materials had opposite nonlinear responses, consistent with previously published data. The technique could be applied to life-time predictions of engineered components by measuring changes in nonlinear response caused by fatigue.

Method and apparatus for measuring stress

DOEpatents

Thompson, R.B.

1983-07-28

A method and apparatus for determining stress in a material independent of micro-structural variations and anisotropies. The method comprises comparing the velocities of two horizontally polarized and horizontally propagating ultrasonic shear waves with interchanged directions of propagation and polarization. The apparatus for carrying out the method comprises periodic permanent magnet-electromagnetic acoustic transducers for generating and detecting the shear waves and means for determining the wave velocities.

Method and apparatus for measuring stress

DOEpatents

Thompson, R. Bruce

1985-06-11

A method and apparatus for determining stress in a material independent of micro-structural variations and anisotropies. The method comprises comparing the velocities of two horizontally polarized and horizontally propagating ultrasonic shear waves with interchanged directions of propagation and polarization. The apparatus for carrying out the method comprises periodic permanent magnet-electromagnetic acoustic transducers for generating and detecting the shear waves and means for determining the wave velocities.

Response of capacitive micromachined ultrasonic transducers

NASA Astrophysics Data System (ADS)

Ge, Lifeng

2008-10-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been developed for airborne ultrasonic applications, acoustic imaging, and chemical and biological detections. Much attention is also paid how to optimize their performance, so that the accurate simulation of the transmitting response of the CMUTs becomes extremely significant. This paper focuses on determining the total input mechanical impedance accountings for damping, and its resistance part is obtained by the calculated natural frequency and equivalent lumped parameters, and the typical 3-dB bandwidth. Thus, the transmitting response can be calculated by using the input mechanical impedance. Moreover, the equivalent electrical circuit can be also established by the determined lumped parameters.

A general-purpose computer program for studying ultrasonic beam patterns generated with acoustic lenses

NASA Technical Reports Server (NTRS)

Roberti, Dino; Ludwig, Reinhold; Looft, Fred J.

1988-01-01

A 3-D computer model of a piston radiator with lenses for focusing and defocusing is presented. To achieve high-resolution imaging, the frequency of the transmitted and received ultrasound must be as high as 10 MHz. Current ultrasonic transducers produce an extremely narrow beam at these high frequencies and thus are not appropriate for imaging schemes such as synthetic-aperture focus techniques (SAFT). Consequently, a numerical analysis program has been developed to determine field intensity patterns that are radiated from ultrasonic transducers with lenses. Lens shapes are described and the field intensities are numerically predicted and compared with experimental results.

Characterization of airborne transducers by optical tomography

PubMed

Bou Matar O; Pizarro; Certon; Remenieras; Patat

2000-03-01

This paper describes the application of an acousto-optic method to the measurement of airborne ultrasound. The method consists of a heterodyne interferometric probing of the pressure emitted by the transducer combined with a tomographic algorithm. The heterodyne interferometer measures the optical phase shift of the probe laser beam, proportional to the acoustic pressure integrated along the light path. A number of projections of the sound field, e.g. a set of ray integrals obtained along parallel paths, are made in moving the transducer to be tested. The main advantage of the method is its very high sensitivity in air (2 x 10(-4) Pa Hz-1/2), combined with a large bandwidth. Using the same principle as X-ray tomography the ultrasonic pressure in a plane perpendicular to the transducer axis can be reconstructed. Several ultrasonic fields emitted by wide-band home made electrostatic transducers, with operating frequencies between 200 and 700 kHz, have been measured. The sensitivities compared favorably with those of commercial airborne transducers.

Apparatus and method for high temperature viscosity and temperature measurements

DOEpatents

Balasubramaniam, Krishnan; Shah, Vimal; Costley, R. Daniel; Singh, Jagdish P.

2001-01-01

A probe for measuring the viscosity and/or temperature of high temperature liquids, such as molten metals, glass and similar materials comprises a rod which is an acoustical waveguide through which a transducer emits an ultrasonic signal through one end of the probe, and which is reflected from (a) a notch or slit or an interface between two materials of the probe and (b) from the other end of the probe which is in contact with the hot liquid or hot melt, and is detected by the same transducer at the signal emission end. To avoid the harmful effects of introducing a thermally conductive heat sink into the melt, the probe is made of relatively thermally insulative (non-heat-conductive) refractory material. The time between signal emission and reflection, and the amplitude of reflections, are compared against calibration curves to obtain temperature and viscosity values.

NDE application of ultrasonic tomography to a full-scale concrete structure.

PubMed

Choi, Hajin; Popovics, John S

2015-06-01

Newly developed ultrasonic imaging technology for large concrete elements, based on tomographic reconstruction, is presented. The developed 3-D internal images (velocity tomograms) are used to detect internal defects (polystyrene foam and pre-cracked concrete prisms) that represent structural damage within a large steel reinforced concrete element. A hybrid air-coupled/contact transducer system is deployed. Electrostatic air-coupled transducers are used to generate ultrasonic energy and contact accelerometers are attached on the opposing side of the concrete element to detect the ultrasonic pulses. The developed hybrid testing setup enables collection of a large amount of high-quality, through-thickness ultrasonic data without surface preparation to the concrete. The algebraic reconstruction technique is used to reconstruct p-wave velocity tomograms from the obtained time signal data. A comparison with a one-sided ultrasonic imaging method is presented for the same specimen. Through-thickness tomography shows some benefit over one-sided imaging for highly reinforced concrete elements. The results demonstrate that the proposed through-thickness ultrasonic technique shows great potential for evaluation of full-scale concrete structures in the field.

Underwater manipulator

DOEpatents

Schrum, Phillip B.; Cohen, George H.

1993-01-01

Self-contained, waterproof, water-submersible, remote-controlled apparatus is provided for manipulating a device, such as an ultrasonic transducer for measuring crack propagation on an underwater specimen undergoing shock testing. The subject manipulator includes metal bellows for transmittal of angular motions without the use of rotating shaft seals or O-rings. Inside the manipulator, a first stepper motor controls angular movement. In the preferred embodiment, the bellows permit the first stepper motor to move an ultrasonic transducer .+-.45 degrees in a first plane and a second bellows permit a second stepper motor to move the transducer .+-.10 degrees in a second plane orthogonal to the first. In addition, an XY motor-driven table provides XY motion.

Ultrasonic propulsion

NASA Astrophysics Data System (ADS)

Allison, Eric

In this investigation, a propulsion system is introduced for propelling and guiding an object through a fluid. Thrust for forward motion and for turning is produced by acoustic waves generated by piezoelectric ultrasonic transducers. The principle of operation of the transducers is described, and methods are presented for the design of the entire system, including the transducers, signal generator, guidance and control system, and the power source. A wirelessly controlled proof-of-concept device was constructed. This device demonstrates the operation and practicality of the propulsion and guidance systems and illustrates that they may be employed in situations where the use of conventional propulsive devices such as propellers or jets is unfeasible.

Ultrasound shear wave imaging

NASA Astrophysics Data System (ADS)

Ye, Shigong; Wu, Junru

2000-05-01

Shear wave propagation properties including phase velocity and attenuation coefficient are indispensable information in materials characterization and nondestructive evaluation. A computer controlled scanning shear-wave ultrasonic imaging system has been developed. It consists of a pair of focusing broadband pvdf transducers of central frequency of 50 MHz immersed in distilled water. Shear waves in a solid specimen are generated by mode-conversion. When ultrasonic waves generated by one of the pvdf transducers impinge upon a solid specimen from water with angle of incidence of θ that is greater than θcr, the critical angle of the longitudinal wave in the solid, only shear waves can propagate in the solid and longitudinal waves become evanescent waves. The shear waves pass through the specimen and received by the other pvdf transducer. Meanwhile, the specimen was scanned by a stepped motor of a step of 10 μm. The system was used to generated shear waves amplitude and phase velocity images of bone specimen of 1280 μm and they are compared with their longitudinal wave counterparts. The results have shown shear wave images can provide additional shear modulus and shear viscous information that longitudinal waves can't provide. The lateral resolution of 60 μm was achieved using shear wave imaging technique applied in bone sample.

Ultrasonic absorption characteristics of porous carbon-carbon ceramics with random microstructure for passive hypersonic boundary layer transition control

NASA Astrophysics Data System (ADS)

Wagner, Alexander; Hannemann, Klaus; Kuhn, Markus

2014-06-01

Preceding studies in the high enthalpy shock tunnel Göttingen of the German Aerospace Center (DLR) revealed that carbon fibre reinforced carbon ceramic (C/C) surfaces can be utilized to damp hypersonic boundary layer instabilities leading to a delay of boundary layer transition onset. To assess the ultrasonic absorption properties of the material, a test rig was set up to measure the reflection coefficient at ambient pressures ranging from 0.1 × 105 to 1 × 105 Pa. For the first time, broadband ultrasonic sound transducers with resonance frequencies of up to 370 kHz were applied to directly cover the frequency range of interest with respect to the second-mode instabilities observed in previous experiments. The reflection of ultrasonic waves from three flat plate test samples with a porous layer thickness between 5 and 30 mm was investigated and compared to an ideally reflecting surface. C/C was found to absorb up to 19 % of the acoustic power transmitted towards the material. The absorption characteristics were investigated theoretically by means of the quasi-homogeneous absorber theory. The experimental results were found to be in good agreement with the theory.

Modeling of ultrasonic wave propagation in composite laminates with realistic discontinuity representation.

PubMed

Zelenyak, Andreea-Manuela; Schorer, Nora; Sause, Markus G R

2018-02-01

This paper presents a method for embedding realistic defect geometries of a fiber reinforced material in a finite element modeling environment in order to simulate active ultrasonic inspection. When ultrasonic inspection is used experimentally to investigate the presence of defects in composite materials, the microscopic defect geometry may cause signal characteristics that are difficult to interpret. Hence, modeling of this interaction is key to improve our understanding and way of interpreting the acquired ultrasonic signals. To model the true interaction of the ultrasonic wave field with such defect structures as pores, cracks or delamination, a realistic three dimensional geometry reconstruction is required. We present a 3D-image based reconstruction process which converts computed tomography data in adequate surface representations ready to be embedded for processing with finite element methods. Subsequent modeling using these geometries uses a multi-scale and multi-physics simulation approach which results in quantitative A-Scan ultrasonic signals which can be directly compared with experimental signals. Therefore, besides the properties of the composite material, a full transducer implementation, piezoelectric conversion and simultaneous modeling of the attached circuit is applied. Comparison between simulated and experimental signals provides very good agreement in electrical voltage amplitude and the signal arrival time and thus validates the proposed modeling approach. Simulating ultrasound wave propagation in a medium with a realistic shape of the geometry clearly shows a difference in how the disturbance of the waves takes place and finally allows more realistic modeling of A-scans. Copyright © 2017 Elsevier B.V. All rights reserved.

A New Low-frequency Sonophoresis System Combined with Ultrasonic Motor and Transducer

NASA Astrophysics Data System (ADS)

Zhu, Pancheng; Peng, Hanmin; Yang, Jianzhi; Mao, Ting; Sheng, Juan

2018-03-01

Low frequency sonophoresis (LFS) is currently being attempted as a transdermal drug delivery method in clinical areas. However, it lacks both an effective control method and the equipment to satisfy the varying drug dosage requirements of individual patients. Herein, a novel method aimed at controlling permeability is proposed and developed, using a pressure control strategy which is based on an accurate, adjustable and non-invasive ultrasound transdermal drug delivery system in in vitro LFS. The system mainly consists of a lead screw linear ultrasonic motor and an ultrasonic transducer, in which the former offers pressure and the latter provides ultrasound wave in the liquid. The ultrasound can enhance non-invasive permeation and the pressure from the motor can control the permeability. The calculated and experimental results demonstrate that the maximum pressure on artificial skin is under the area with the maximum vibration amplitude of the ultrasonic transducer, and the total pressure consists of acoustic pressure from the transducer and approximate static pressure from the motor. Changing the static pressure from the ultrasonic motor can effectively control the non-invasive permeability, by adjusting the duty ratio or the amplitude of the motor’s driving voltage. In addition, the permeability control of calcein by thrust control is realized in 15 min, indicating the suitability of this method for application in accurate medical technology. The obtained results reveal that the issue of difficult permeability control can be addressed, using this control method in in vitro LFS to open up a route to the design of accurate drug delivery technology for individual patients.

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review.

PubMed

Zhang, Shujun; Li, Fei; Jiang, Xiaoning; Kim, Jinwook; Luo, Jun; Geng, Xuecang

2015-03-01

Relaxor-PbTiO 3 (PT) based ferroelectric crystals with the perovskite structure have been investigated over the last few decades due to their ultrahigh piezoelectric coefficients ( d 33 > 1500 pC/N) and electromechanical coupling factors ( k 33 > 90%), far outperforming state-of-the-art ferroelectric polycrystalline Pb(Zr,Ti)O 3 ceramics, and are at the forefront of advanced electroacoustic applications. In this review, the performance merits of relaxor-PT crystals in various electroacoustic devices are presented from a piezoelectric material viewpoint. Opportunities come from not only the ultrahigh properties, specifically coupling and piezoelectric coefficients, but through novel vibration modes and crystallographic/domain engineering. Figure of merits (FOMs) of crystals with various compositions and phases were established for various applications, including medical ultrasonic transducers, underwater transducers, acoustic sensors and tweezers. For each device application, recent developments in relaxor-PT ferroelectric crystals were surveyed and compared with state-of-the-art polycrystalline piezoelectrics, with an emphasis on their strong anisotropic features and crystallographic uniqueness, including engineered domain - property relationships. This review starts with an introduction on electroacoustic transducers and the history of piezoelectric materials. The development of the high performance relaxor-PT single crystals, with a focus on their uniqueness in transducer applications, is then discussed. In the third part, various FOMs of piezoelectric materials for a wide range of ultrasound applications, including diagnostic ultrasound, therapeutic ultrasound, underwater acoustic and passive sensors, tactile sensors and acoustic tweezers, are evaluated to provide a thorough understanding of the materials' behavior under operational conditions. Structure-property-performance relationships are then established. Finally, the impacts and challenges of relaxor-PT crystals are summarized to guide on-going and future research in the development of relaxor-PT crystals for the next generation electroacoustic transducers.

A computerized self-compensating system for ultrasonic inspection of airplane structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komsky, I.N.; Achenbach, J.D.; Hagemaier, D.

1993-12-31

Application of a self-compensating technique for ultrasonic inspection of airplane structures makes it possible not only to detect cracks in the different layers of joints but also to obtain information on crack sizes. A prototype computerized ultrasonic system, which utilizes the self-compensating method, has been developed for non-destructive inspection of multilayered airplane structures with in-between sealants, such as bolted joints in tail connections. Industrial applications of the system would require deployment of commercially available portable modules for data acquisition and processing. A portable ultrasonic flaw detector EPOCH II manual scanners and HandiScan, and SQL and FCS software modules form themore » PC-based TestPro system have been selected for initial tests. A pair of contact angle-beam transducers were used to generate shear waves in the material. Both hardware and software components of the system have been modified for the application in conjunction with the self-compensating technique. The system has bene tested on two calibration specimens with artificial flaws of different sizes in internal layers of multilayered structures. Ultrasonic signals transmitted through and reflected from the artificial flaws have bene discriminated and characterized using multiple time domain amplitude gates. Then the ratios of the reflection and transmission coefficients, R/T, were calculated for several positions of the transducers. Inspection of measured R/T curves shows it is difficult to visually associate curve shapes with corresponding flaw sizes and orientation. Hence for online classification of these curve shapes, application of an adaptive signal classifier was considered. Several different types and configurations of the classifiers, including a neural network, have been tested. Test results showed that improved performance of the classifier can be achieved by combination of a back-propagation neural network with a signal pre-processing module.« less

Proposal of ultrasonic-assisted mid-infrared spectroscopy for incorporating into daily life like smart-toilet and non-invasive blood glucose sensor

NASA Astrophysics Data System (ADS)

Kitazaki, Tomoya; Mori, Keita; Yamamoto, Naoyuki; Wang, Congtao; Kawashima, Natsumi; Ishimaru, Ichiro

2017-07-01

We proposed the extremely compact beans-size snap-shot mid-infrared spectroscopy that will be able to be built in smartphones. And also the easy preparation method of thin-film samples generated by ultrasonic standing wave is proposed. Mid-infrared spectroscopy is able to identify material components and estimate component concentrations quantitatively from absorption spectra. But conventional spectral instruments were very large-size and too expensive to incorporate into daily life. And preparations of thin-film sample were very troublesome task. Because water absorption in mid-infrared lights is very strong, moisture-containing-sample thickness should be less than 100[μm]. Thus, midinfrared spectroscopy has been utilized only by analytical experts in their laboratories. Because ultrasonic standing wave is compressional wave, we can generate periodical refractive-index distributions inside of samples. A high refractiveindex plane is correspond to a reflection boundary. When we use a several MHz ultrasonic transducer, the distance between sample surface and generated first node become to be several ten μm. Thus, the double path of this distance is correspond to sample thickness. By combining these two proposed methods, as for liquid samples, urinary albumin and glucose concentrations will be able to be measured inside of toilet. And as for solid samples, by attaching these apparatus to earlobes, the enhancement of reflection lights from near skin surface will create a new path to realize the non-invasive blood glucose sensor. Using the small ultrasonic-transducer whose diameter was 10[mm] and applied voltage 8[V], we detected the internal reflection lights from colored water as liquid sample and acrylic board as solid sample.

Development of Integrated and Flexible Ultrasonic Transducers for Aerospace Applications

NASA Astrophysics Data System (ADS)

Wu, Kuo-Ting

2011-12-01

High temperature (HT) integrated (IUTs) and flexible ultrasonic transducers (FUTs) for potential aerospace applications in the area of nondestructive testing (NDT) and structural health monitoring (SHM) are developed. The main merits are that IUTs can be fabricated on-site and FUTs are feasible and attractive for on-site installation. The piezoelectric composite films of these HT ultrasonic transducers (HTUTs) are made by sol-gel spray fabrication. Lead-zirconate titanate composite (PZT-c), bismuth titanate composite (BIT-c), or lithium niobate composite (LiNbO3-c) films were coated onto metallic substrates with planar and curved surfaces and investigated as IUTs. Their maximum operating temperatures were demonstrated at up to 150°C, 400°C, and 800°C, respectively. PZT-c or BIT-c films were coated onto 75 mum or 38 mum thick metallic membranes and were investigated as FUTs. They can be bonded onto flat or curved surfaces for NDT and SHM. An FUT made of BIT-c film coated onto a stainless steel membrane glued onto a steel plate was performed at up to 300°C. Besides being coated onto metallic materials, sol-gel sprayed composite films were also coated onto graphite/epoxy (Gr/Ep) plates as IUTs and 50 mum thick polyimide films as FUTs for the thickness and delamination evaluation. Using acoustic mode conversion techniques, HTUTs for shear (S) wave, surface acoustic wave (SAW), and plate acoustic wave (PAW), have been developed. HT ultrasonic probes simultaneously producing one longitudinal (L) and two orthogonally polarized S waves were demonstrated in metallic and Plexiglas probes. The potential applications of these probes were discussed. Also applying mode conversion approaches, HT symmetrical, anti-symmetrical, and shear horizontal (SH) PAWs UTs for NDT and SHM were developed. The results showed that the SH PAWs may be the best candidate for NDT and SHM purposes for plate structures. Generation and detection of guided acoustic waves for NDT were demonstrated by using IUTs or FUTs with metallic wedges, mechanical gratings or interdigital transducers as well. The experiments with these three approaches were performed at up to 300°C. Furthermore, two non-contact ultrasonic measurement techniques by sol-gel sprayed composite films were presented in this thesis. One is using lasers to generate ultrasound and IUTs as receivers, and the other is using induction-based non-contact ultrasonic measurement technique with IUTs. NDT of bonded composite patches on aluminum plates was performed using laser generated ultrasound and IUT receivers. The induction-based ultrasonic measurement of a Gr/Ep composite plate rotated at 1000 rpm was demonstrated. The IUTs and FUTs developed in this thesis are able to provide signals with good signal-to-noise ratios at elevated temperature on structures and parts having a curved surface. They are light weight and miniature in size. They may be used for real-time, in situ, nondestructive local and global (large area) damage detection and assessment in aerospace NDT and SHM applications.

Control of liquid crystal molecular orientation using ultrasound vibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taniguchi, Satoki; Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321; Koyama, Daisuke

2016-03-07

We propose a technique to control the orientation of nematic liquid crystals using ultrasound and investigate the optical characteristics of the oriented samples. An ultrasonic liquid crystal cell with a thickness of 5–25 μm and two ultrasonic lead zirconate titanate transducers was fabricated. By exciting the ultrasonic transducers, the flexural vibration modes were generated on the cell. An acoustic radiation force to the liquid crystal layer was generated, changing the molecular orientation and thus the light transmission. By modulating the ultrasonic driving frequency and voltage, the spatial distribution of the molecular orientation of the liquid crystals could be controlled. The distributionmore » of the transmitted light intensity depends on the thickness of the liquid crystal layer because the acoustic field in the liquid crystal layer is changed by the orientational film.« less

Nonlinear propagation in ultrasonic fields: measurements, modelling and harmonic imaging.

PubMed

Humphrey, V F

2000-03-01

In high amplitude ultrasonic fields, such as those used in medical ultrasound, nonlinear propagation can result in waveform distortion and the generation of harmonics of the initial frequency. In the nearfield of a transducer this process is complicated by diffraction effects associated with the source. The results of a programme to study the nonlinear propagation in the fields of circular, focused and rectangular transducers are described, and comparisons made with numerical predictions obtained using a finite difference solution to the Khokhlov-Zabolotskaya-Kuznetsov (or KZK) equation. These results are extended to consider nonlinear propagation in tissue-like media and the implications for ultrasonic measurements and ultrasonic heating are discussed. The narrower beamwidths and reduced side-lobe levels of the harmonic beams are illustrated and the use of harmonics to form diagnostic images with improved resolution is described.

Optimization design of high power ultrasonic circular ring radiator in coupled vibration.

PubMed

Xu, Long; Lin, Shuyu; Hu, Wenxu

2011-10-01

This paper presents a new high power ultrasonic (HPU) radiator, which consists of a transducer, an ultrasonic horn, and a metal circular ring. Both the transducer and horn in longitudinal vibrations are used to drive a metal circular ring in a radial-axial coupled vibration. This coupled vibration cannot only generate ultrasound in both the radial and axial directions, but also focus the ultrasound inside the circular ring. Except for the radial-axial coupled vibration mode, the third longitudinal harmonic vibration mode with relative large vibration amplitude is also detected, which can be used as another operation mode. Overall, the HPU with these two vibration modes should have good potential to be applied in liquid processing, such as sonochemistry, ultrasonic cleaning, and Chinese herbal medicine extraction. Copyright © 2011 Elsevier B.V. All rights reserved.

Detection of in-plane displacements of acoustic wave fields using extrinsic Fizeau fiber interferometric sensors

NASA Technical Reports Server (NTRS)

Dhawan, R.; Gunther, M. F.; Claus, R. O.

1991-01-01

Quantitative measurements of the in-plane particle displacement components of ultrasonic surface acoustic wave fields using extrinsic Fizeau fiber interferometric (EFFI) sensors are reported. Wave propagation in materials and the fiber sensor elements are briefly discussed. Calibrated experimental results obtained for simulated acoustic emission events on homogeneous metal test specimens are reported and compared to previous results obtained using piezoelectric transducers.

Piezoelectric micromachined ultrasonic transducers and micropumps: from design to optomicrofluidic applications

NASA Astrophysics Data System (ADS)

Khazaaleh, Shadi; Saeed, Numan; Taha, Inas; Madzik, Mateusz T.; Viegas, Jaime

2017-02-01

In this work, we present the experimental results of a new wafer-level production platform for aluminum nitride based piezoelectric micromachined ultrasonic transducers (PMUTs), operated by lower than 10 V peak-to-peak signals, and covering ultrasonic frequency ranges from 200 kHz up to 10 MHz, with measured axial displacements ranging from a few nanometers up to 600 nm. The fabricated devices have a low footprint of (130x130) μm2. The experimental results are in excellent agreement with finite-element method simulations. The small footprint and driving voltages of these piezo-microactuators are well suited for the development of micropump and micromixer designs for portable microfluidics applications.

The application of water coupled nonlinear ultrasonics to quantify the dislocation density in aluminum 1100

NASA Astrophysics Data System (ADS)

Mostavi, Amir; Tehrani, N.; Kamali, N.; Ozevin, D.; Chi, S. W.; Indacochea, J. E.

2017-02-01

This article investigates water coupled nonlinear ultrasonic method to measure the dislocation density in aluminum 1100 specimens. The different levels of dislocation densities are introduced to the samples by applying different levels of plastic strains by tensile loading. The ultrasonic testing includes 2.25 MHz transducer as transmitter and 5.0 MHz transducer as receiver in an immersion tank. The results of immersion experiments are compared with oil-coupled experiments. While water has significant nonlinearity within itself, the immersion ultrasound results agree with the literature of oil coupled ultrasound results of the specimens that the nonlinearity coefficient increases with the increase of dislocation density in aluminum.

Fabrication and modeling of bismuth titanate-PZT ceramic transducers for high temperature applications

NASA Astrophysics Data System (ADS)

Reinhardt, B.; Searfass, C.; Cyphers, R.; Sinding, K.; Pheil, C.; Tittmann, B.

2013-01-01

Utilization of a spray-on deposition technique of ferroelectric bismuth titanate (Bi4Ti3O12) composites has a competitive advantage to standard ultrasonic transducers. These can conform to curved surfaces, can operate at high temperature (Curie-Weiss temperature 685 °C) and are mechanically well-coupled to a substrate. However, an issue with many high temperature transducers such as bismuth titanate ceramics is that they have relatively low transduction efficiency, i.e. d33 is about 12-14 pC/F in Bi4Ti3O12 versus 650 pC/F in PZT-5H. It is a common conception that high-temperature capability comes at the cost of electro-mechanical coupling. It will be shown that the high temperature capability of bismuth-titanate-PZT composite transducers using the spray-on deposition technique previously developed, improves the electro-mechanical coupling while maintaining the high temperature performance and mechanical coupling. This material could provide advantages in harsh environments where high signal-to-noise ratios are needed.

Underwater manipulator

DOEpatents

Schrum, P.B.; Cohen, G.H.

1993-04-20

Self-contained, waterproof, water-submersible, remote-controlled apparatus is described for manipulating a device, such as an ultrasonic transducer for measuring crack propagation on an underwater specimen undergoing shock testing. The subject manipulator includes metal bellows for transmittal of angular motions without the use of rotating shaft seals or O-rings. Inside the manipulator, a first stepper motor controls angular movement. In the preferred embodiment, the bellows permit the first stepper motor to move an ultrasonic transducer [plus minus]45 degrees in a first plane and a second bellows permit a second stepper motor to move the transducer [plus minus]10 degrees in a second plane orthogonal to the first. In addition, an XY motor-driven table provides XY motion.

Helium Bottle Pressure Measurement by Portable Ultrasonic Technique

DTIC Science & Technology

1989-02-07

revision extends the study to include EMI testing, and -develorynent of g Rrotgtype tester . The Contractor shall: 1. Perform EMI test of ultrasonic eq...amp/1 watt power ap- plied to the bridgerires. The tester pulse of 250 volts for 100 ns at 1500 pps has an average value of 250v x 100ns x 1500pps...34 connector. Mount transducer in fixture and connect transducer to cable microdot connector. 5. Pulse-Echo transit time measurement: Assure that the

Cellular-foam polypropylene ferroelectrets with increased film thickness and reduced resonance frequency

NASA Astrophysics Data System (ADS)

Sborikas, Martynas; Wegener, Michael

2013-12-01

Ferroelectrets are piezoelectric materials suitable for acoustic applications such as airborne ultrasonic transducers. Typical ferroelectrets exhibit resonance frequencies in the high kHz to low MHz range. In order to decrease the transducer resonance frequencies to the low kHz range, processes such as gas-diffusion expansion and electric charging were adjusted to cellular films which are initially twice as thick as in earlier studies. The demonstrated film expansion and electric charging lead to mechanically soft cellular structures which show high piezoelectric activities with coefficients up to 130 pC/N. Due to the simultaneously increased film thicknesses, the resonance frequencies are lowered down to about 233 kHz.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fitriana, Karina Nur, E-mail: nurfitriana.karina@gmail.com; Hafizah, Mas Ayu Elita, E-mail: kemasayu@yahoo.com; Manaf, Azwar, E-mail: azwar@ui.ac.id

Synthesis of single phased SrO.6Fe{sub 2-x}Mn{sub x/2}Ti{sub x/2}O{sub 3} (x = 0.0; 0.5; and 1.0) nanoparticles has been prepared through mechanical alloying, assisted with the ultrasonic destruction process. Monocrystalline particles were obtained when x = 0 treated with ultrasonic destruction at 55 μm of transducer amplitude. Average particle size and crystallite size were reduced significantly from 723 nm to ∼87 nm for x = 0. The particle size was not significantly reduced when x = 0.5 and x = 1 was changed. On the other hand, substitution of Ti elements on some of Fe elements expectedly had a major effectmore » on reducing particle size. This was proven by larger size on both particle and crystallite size at x = 1 rather than x = 0.5, with comparison respectively 2:1 (in nm). In addition, a higher transducer power was required for modifying Strontium Hexaferrite (SHF) with more Ti elements and a bigger size of pre-ultrasonic destructed sample. It is concluded that the amplitude of the transducer in ultrasonic destruction process and the element of ionic substitution affects both average particle size and crystallite size of SHF.« less

One-dimensional pressure transfer models for acoustic-electric transmission channels

NASA Astrophysics Data System (ADS)

Wilt, K. R.; Lawry, T. J.; Scarton, H. A.; Saulnier, G. J.

2015-09-01

A method for modeling piezoelectric-based ultrasonic acoustic-electric power and data transmission channels is presented. These channels employ piezoelectric disk transducers to convey signals across a series of physical layers using ultrasonic waves. This model decomposes the mechanical pathway of the signal into individual ultrasonic propagation layers which are generally independent of the layer's adjacent domains. Each layer is represented by a two-by-two traveling pressure wave transfer matrix which relates the forward and reverse pressure waves on one side of the layer to the pressure waves on the opposite face, where each face is assumed to be in contact with a domain of arbitrary reference acoustic impedance. A rigorous implementation of ultrasonic beam spreading is introduced and implemented within applicable domains. Compatible pressure-wave models for piezoelectric transducers are given, which relate the electric voltage and current interface of the transducer to the pressure waves on one mechanical interface while also allowing for passive acoustic loading of the secondary mechanical interface. It is also shown that the piezoelectric model's electrical interface is compatible with transmission line parameters (ABCD-parameters), allowing for connection of electronic components and networks. The model is shown to be capable of reproducing the behavior of realistic physical channels.

Contributions to the study of inductive transducers for measuring the amplitude of vibrations in solid media

NASA Technical Reports Server (NTRS)

Dragan, O.; Galan, N.; Sirbu, A.; Ghita, C.

1974-01-01

The design and construction of inductive transducers for measuring the vibrations in metal bars at ultrasonic frequencies are discussed. Illustrations of the inductive transducers are provided. The quantitative relations that are useful in designing the transducers are analyzed. Mathematical models are developed to substantiate the theoretical considerations. Results obtained with laboratory equipment in testing specified metal samples are included.

MEMS ultrasonic transducer for monitoring of steel structures

NASA Astrophysics Data System (ADS)

Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2002-06-01

Ultrasonic methods can be used to monitor crack propagation, weld failure, or section loss at critical locations in steel structures. However, ultrasonic inspection requires a skilled technician, and most commonly the signal obtained at any inspection is not preserved for later use. A preferred technology would use a MEMS device permanently installed at a critical location, polled remotely, and capable of on-chip signal processing using a signal history. We review questions related to wave geometry, signal levels, flaw localization, and electromechanical design issues for microscale transducers, and then describe the design, characterization, and initial testing of a MEMS transducer to function as a detector array. The device is approximately 1-cm square and was fabricated by the MUMPS process. The chip has 23 sensor elements to function in a phased array geometry, each element containing 180 hexagonal polysilicon diaphragms with a typical leg length of 49 microns and an unloaded natural frequency near 3.5 MHz. We first report characterization studies including capacitance-voltage measurements and admittance measurements, and then report initial experiments using a conventional piezoelectric transducer for excitation, with successful detection of signals in an on-axis transmission experiment and successful source localization from phased array performance in an off-axis transmission experiment.

Rock Driller

NASA Technical Reports Server (NTRS)

Peterson, Thomas M.

2001-01-01

The next series of planetary exploration missions require a method of extracting rock and soil core samples. Therefore a prototype ultrasonic core driller (UTCD) was developed to meet the constraints of Small Bodies Exploration and Mars Sample Return Missions. The constraints in the design are size, weight, power, and axial loading. The ultrasonic transducer requires a relatively low axial load, which is one of the reasons this technology was chosen. The ultrasonic generator breadboard section can be contained within the 5x5x3 limits and weighs less than two pounds. Based on results attained the objectives for the first phase were achieved. A number of transducer probes were made and tested. One version only drills, and the other will actually provide a small core from a rock. Because of a more efficient transducer/probe, it will run at very low power (less than 5 Watts) and still drill/core. The prototype generator was built to allow for variation of all the performance-effecting elements of the transducer/probe/end effector, i.e., pulse, duty cycle, frequency, etc. The heart of the circuitry is what will be converted to a surface mounted board for the next phase, after all the parameters have been optimized and the microprocessor feedback can be installed.

Ultrasonic/Sonic Drill for High Temperature Application

NASA Technical Reports Server (NTRS)

Bao, Xiaoqi; Bar-Cohen, Yoseph; Scott, James; Sherrit, Stewart; Widholm, Scott; Badescu, Mircea; Shrout, Tom; Jones, Beth

2010-01-01

Venus is one of the many significant scientific targets for NASA. New rock sampling tools with the ability to be operated at high temperatures of the order of 460 deg C are required for surface in-situ sampling/analysis missions. Piezoelectric materials such as LiNbO? crystals and Bismuth Titanate are potentially operational at the temperature range found on the surface of Venus. A study of the feasibility of producing piezoelectric drills for a temperature up to 500 deg C was conducted. The study includes investigation of the high temperature properties of piezoelectric crystals and ceramics with different formulas and doping. Several prototypes of Ultrasonic/Sonic Drill/Corers (USDC) driven by transducers using the high temperate piezoelectric ceramics and single LiNbO? crystal were fabricated. The transducers were analyzed by scanning the impedance at room temperature and 500 deg C under both low and high voltages. The drilling performances were tested at temperature up to 500 deg C. Preliminary results were previously reported [Bao et al, 2009]. In this paper, the progress is presented and the future works for performance improvements are discussed.

Effect of ultrasonic agitation on push-out bond strength and adaptation of root-end filling materials.

PubMed

Alcalde, Murilo Priori; Vivan, Rodrigo Ricci; Marciano, Marina Angélica; Duque, Jussaro Alves; Fernandes, Samuel Lucas; Rosseto, Mariana Bailo; Duarte, Marco Antonio Hungaro

2018-05-01

This study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength. Sixty maxillary canines were divided into 6 groups ( n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine. Ultrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA ( p < 0.05). US improved the push-out bond strength for all the cements ( p < 0.05). The US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.

A sonic transducer to detect fluid leaks

NASA Technical Reports Server (NTRS)

Cimerman, I.; Janus, J.

1972-01-01

Ultrasonic detector utilizes set of contact transducers and bandpass filters to detect and analyze sonic energy produced by flow or leakage. Detector covers wide frequency range and is operable at cryogenic temperatures and in vacuum.

Electroacoustics modeling of piezoelectric welders for ultrasonic additive manufacturing processes

NASA Astrophysics Data System (ADS)

Hehr, Adam; Dapino, Marcelo J.

2016-04-01

Ultrasonic additive manufacturing (UAM) is a recent 3D metal printing technology which utilizes ultrasonic vibrations from high power piezoelectric transducers to additively weld similar and dissimilar metal foils. CNC machining is used intermittent of welding to create internal channels, embed temperature sensitive components, sensors, and materials, and for net shaping parts. Structural dynamics of the welder and work piece influence the performance of the welder and part quality. To understand the impact of structural dynamics on UAM, a linear time-invariant model is used to relate system shear force and electric current inputs to the system outputs of welder velocity and voltage. Frequency response measurements are combined with in-situ operating measurements of the welder to identify model parameters and to verify model assumptions. The proposed LTI model can enhance process consistency, performance, and guide the development of improved quality monitoring and control strategies.

Ultrasonic scanning system for in-place inspection of brazed tube joints

NASA Technical Reports Server (NTRS)

Haynes, J. L.; Wages, C. G.; Haralson, H. S. (Inventor)

1973-01-01

A miniaturized ultrasonic scanning system for nondestructive in-place, non-immersion testing of brazed joints in stainless-steel tubing is described. The system is capable of scanning brazed tube joints, with limited clearance access, in 1/4 through 5/8 inch union, tee, elbow and cross configurations. The system has the capability to detect defective conditions now associated with material density changes in addition to those which are depended upon density variations. The system includes a miniaturized scanning head assembly that fits around a tube joint and rotates the transducer around and down the joint in a continuous spiral motion. The C-scan recorder is similar in principle to conventional models except that it was specially designed to track the continuous spiral scan of the tube joint. The scanner and recorder can be operated with most commercially available ultrasonic flaw detectors.

Nonlinear Characterization of Half and Full Wavelength Power Ultrasonic Devices

NASA Astrophysics Data System (ADS)

Mathieson, Andrew; Cerisola, Niccolò; Cardoni, Andrea

It is well known that power ultrasonic devices whilst driven under elevated excitation levels exhibit nonlinear behaviors. If no attempt is made to understand and subsequently control these behaviors, these devices can exhibit poor performance or even suffer premature failure. This paper presents an experimental method for the dynamic characterization of a commercial ultrasonic transducer for bone cutting applications (Piezosurgery® Device) operated together with a variety of rod horns that are tuned to operate in a longitudinal mode of vibration. Near resonance responses, excited via a burst sine sweep method were used to identify nonlinear responses exhibited by the devices, while experimental modal analysis was performed to identify the modal parameters of the longitudinal modes of vibration of the assemblies between 0-80 kHz. This study tries to provide an understanding of the effects that geometry and material choices may have on the nonlinear behavior of a tuned device.

Chaos and Beyond in a Water Filled Ultrasonic Resonance System

NASA Technical Reports Server (NTRS)

Lazlo, Adler; Yost, W.; Cantrell, John H.

2013-01-01

Finite amplitude ultrasonic wave resonances in a one-dimensional liquid-filled cavity, formed by a narrow band transducer and a plane reflector, are reported. The resonances are observed to include not only the expected harmonic and subharmonic signals (1,2) but chaotic signals as well. The generation mechanism requires attaining a threshold value of the driving amplitude that the liquid-filled cavity system becomes sufficiently nonlinear in response. The nonlinear features of the system were recently investigated via the construction of an ultrasonic interferometer having optical precision. The transducers were compressional, undamped quartz and lithium niobate crystals having the frequency range 1-10 MHz, driven by a high power amplifier. Both an optical diffraction system to characterize the diffraction pattern of laser light normally incident to the cavity and a receiving transducer attached to an aligned reflector with lapped flat and parallel surfaces were used to assess the generated resonance response in the cavity. At least 5 regions of excitation are identified.

Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuneda, H.; Matsukawa, S.; Takayanagi, S.

The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurementsmore » and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.« less

Rapidly quantifying the relative distention of a human bladder

NASA Technical Reports Server (NTRS)

Companion, John A. (Inventor); Heyman, Joseph S. (Inventor); Mineo, Beth A. (Inventor); Cavalier, Albert R. (Inventor); Blalock, Travis N. (Inventor)

1991-01-01

A device and method was developed to rapidly quantify the relative distention of the bladder of a human subject. An ultrasonic transducer is positioned on the human subject near the bladder. A microprocessor controlled pulser excites the transducer by sending an acoustic wave into the human subject. This wave interacts with the bladder walls and is reflected back to the ultrasonic transducer where it is received, amplified, and processed by the receiver. The resulting signal is digitized by an analog to digital converter, controlled by the microprocessor again, and is stored in data memory. The software in the microprocessor determines the relative distention of the bladder as a function of the propagated ultrasonic energy. Based on programmed scientific measurements and the human subject's past history as contained in program memory, the microprocessor sends out a signal to turn on any or all of the available alarms. The alarm system includes and audible alarm, the visible alarm, the tactile alarm, and the remote wireless alarm.

Modeling NDT piezoelectric ultrasonic transmitters.

PubMed

San Emeterio, J L; Ramos, A; Sanz, P T; Ruíz, A; Azbaid, A

2004-04-01

Ultrasonic NDT applications are frequently based on the spike excitation of piezoelectric transducers by means of efficient pulsers which usually include a power switching device (e.g. SCR or MOS-FET) and some rectifier components. In this paper we present an approximate frequency domain electro-acoustic model for pulsed piezoelectric ultrasonic transmitters which, by integrating partial models of the different stages (driving electronics, tuning/matching networks and broadband piezoelectric transducer), allows the computation of the emission transfer function and output force temporal waveform. An approximate frequency domain model is used for the evaluation of the electrical driving pulse from the spike generator. Tuning circuits, interconnecting cable and mechanical impedance matching layers are modeled by means of transmission lines and the classical quadripole approach. The KLM model is used for the piezoelectric transducer. In addition, a PSPICE scheme is used for an alternative simulation of the broadband driving spike, including the accurate evaluation of non-linear driving effects. Several examples illustrate the capabilities of the specifically developed software.

Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation

NASA Astrophysics Data System (ADS)

Tsuneda, H.; Matsukawa, S.; Takayanagi, S.; Mizuno, K.; Yanagitani, T.; Matsukawa, M.

2015-02-01

The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurements and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.

Estimation of some transducer parameters in a broadband piezoelectric transmitter by using an artificial intelligence technique.

PubMed

Ruíz, A; Ramos, A; San Emeterio, J L

2004-04-01

An estimation procedure to efficiently find approximate values of internal parameters in ultrasonic transducers intended for broadband operation would be a valuable tool to discover internal construction data. This information is necessary in the modelling and simulation of acoustic and electrical behaviour related to ultrasonic systems containing commercial transducers. There is not a general solution for this generic problem of parameter estimation in the case of broadband piezoelectric probes. In this paper, this general problem is briefly analysed for broadband conditions. The viability of application in this field of an artificial intelligence technique supported on the modelling of the transducer internal components is studied. A genetic algorithm (GA) procedure is presented and applied to the estimation of different parameters, related to two transducers which are working as pulsed transmitters. The efficiency of this GA technique is studied, considering the influence of the number and variation range of the estimated parameters. Estimation results are experimentally ratified.

New symmetric reflector ultrasonic transducers (SRUT).

PubMed

Toda, Minoru

2009-10-01

This paper proposes a new structure composed of reflector plates mounted in front and in back of the transducer at an angle of 45 degrees, so that acoustic waves from front and back of the transducer are combined to form a single main beam. This principle is applicable to both transmitters and receivers. Because the propagation path lengths of the 2 beams are identical, they constructively add at all frequencies. Theoretical investigations revealed that far field directivity becomes sharper and acoustic pressure output is doubled. Experiments using an air ultrasonic transducer constructed of 50-kHz polyvinylidene fluoride corrugated film has shown doubled acoustic pressure in the far field, and the predicted sharper directivity has been observed. The reflector structure has been also applied to a 2.6-MHz lead zirconate titanate transducer in water with matching layers at both surfaces which has shown almost doubled bandwidth compared with an air backing structure, and doubled output power in continuous drive. Also pulse echo experiments have shown the effectiveness of this scheme.

Applicator for in-vitro ultrasound-activated targeted drug delivery

NASA Astrophysics Data System (ADS)

Gerold, B.; Gourevich, D.; Volovick, A.; Xu, D.; Arditti, F.; Prentice, P.; Cochran, S.; Gnaim, J.; Medan, Y.; Wang, L.; Melzer, A.

2012-10-01

Reducing toxicity and improving uptake of cancer drugs in tumors are important goals of targeted drug delivery (TDD). Ultrasonic drug release from various encapsulants has been a focus of many research groups. However, a single standard ultrasonic device, viable for use by biologists, is not currently present in the market. The device reported here is designed to allow investigation of the impact of ultrasound on cellular uptake and cell viability in-vitro. In it, single-element transducers with different operating frequencies are mounted below a standard 96-well plate. The plate is moved above the transducers, such that each line of wells can be sonicated at a different frequency. To assess the device, 96-well plates were seeded with cells and sonicated using different ultrasonic parameters, with and without doxorubicin. Cell viability was measured by colorimetric MTT assay and the uptake of doxorubicin by cells was also determined. The device proved to be highly viable in preliminary tests; it demonstrated that change in ultrasonic parameters produces different effect on cells. For example, increase in uptake of doxorubicin was demonstrated following ultrasound application. The growing interest in ultrasound-activated TDD emphasizes the need for standardization of the ultrasound device and the one reported here may offer some indications of how that may be achieved. It is planned to further improve the prototype by increasing the number of ultrasonic frequencies and degrees of freedom for each transducer.

A physical model for the acousto-ultrasonic method. Ph.D. Thesis Final Report

NASA Technical Reports Server (NTRS)

Kiernan, Michael T.; Duke, John C., Jr.

1990-01-01

A basic physical explanation, a model, and comments on NDE application of the acousto-ultrasonic (AU) method for composite materials are presented. The basis of this work is a set of experiments where a sending and a receiving piezoelectric transducer were both oriented normal to the surface, at different points, on aluminum plates, various composite plates, and a tapered aluminum plate. The purpose and basic idea is introduced. Also, general comments on the AU method are offered. A literature review is offered for areas pertinent, such as composite materials, wave propagation, ultrasonics, and the AU. Special emphasis is given to theory which is used later on and past experimental results that are important to the physical understanding of the AU method. The experimental set-up, procedure, and the ensuing analysis are described. The experimental results are presented in both a quantitative and qualitative manner. A physical understanding of experimental results based on elasticity solution is furnished. Modeling and applications of the AU method is discussed for composite material and general conclusions are stated. The physical model of the AU method for composite materials is offered, something which has been much needed and sorely lacking. This physical understanding is possible due to the extensive set of experimental measurements, also reported.

Non-contact ultrasonic gas flow metering using air-coupled leaky Lamb waves.

PubMed

Fan, Zichuan; Jiang, Wentao; Wright, William M D

2018-04-23

This paper describes a completely non-contact ultrasonic method of gas flow metering using air-coupled leaky Lamb waves. To show proof of principle, a simplified representation of gas flow in a duct, comprising two separated thin isotropic plates with a gas flowing between them, has been modelled and investigated experimentally. An airborne compression wave emitted from an air-coupled capacitive ultrasonic transducer excited a leaky Lamb wave in the first plate in a non-contact manner. The leakage of this Lamb wave crossed the gas flow at an angle between the two plates as a compression wave, and excited a leaky Lamb wave in the second plate. An air-coupled capacitive ultrasonic transducer on the opposite side of this second plate then detected the airborne compression wave leakage from the second Lamb wave. As the gas flow shifted the wave field between the two plates, the point of Lamb wave excitation in the second plate was displaced in proportion to the gas flow rate. Two such measurements, in opposite directions, formed a completely non-contact contra-propagating Lamb wave flow meter, allowing measurement of the flow velocity between the plates. A COMSOL Multiphysics® model was used to visualize the wave fields, and accurately predicted the time differences that were then measured experimentally. Experiments using different Lamb wave frequencies and plate materials were also similarly verified. This entirely non-contact airborne approach to Lamb wave flow metering could be applied in place of clamp-on techniques in thin-walled ducts or pipes. Copyright © 2018 Elsevier B.V. All rights reserved.

Physical interpretation and development of ultrasonic nondestructive evaluation techniques applied to the quantitative characterization of textile composite materials

NASA Technical Reports Server (NTRS)

Miller, James G.

1994-01-01

In this Progress Report, we describe our continuing research activities concerning the development and implementation of advanced ultrasonic nondestructive evaluation methods applied to the inspection and characterization of complex composite structures. We explore the feasibility of implementing medical linear array imaging technology as a viable ultrasonic-based nondestructive evaluation method to inspect and characterize complex materials. As an initial step toward the application of linear array imaging technology to the interrogation of a wide range of complex composite structures, we present images obtained using an unmodified medical ultrasonic imaging system of two epoxy-bonded aluminum plate specimens, each with intentionally disbonded regions. These images are compared with corresponding conventional ultrasonic contact transducer measurements in order to assess whether these images can detect disbonded regions and provide information regarding the nature of the disbonded region. We present a description of a standoff/delay fixture which has been designed, constructed, and implemented on a Hewlett-Packard SONOS 1500 medical imaging system. This standoff/delay fixture, when attached to a 7.5 MHz linear array probe, greatly enhances our ability to interrogate flat plate specimens. The final section of this Progress Report describes a woven composite plate specimen that has been specially machined to include intentional flaws. This woven composite specimen will allow us to assess the feasibility of applying linear array imaging technology to the inspection and characterization of complex textile composite materials. We anticipate the results of this on-going investigation may provide a step toward the development of a rapid, real-time, and portable method of ultrasonic inspection and characterization based on linear array technology.

Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

PubMed Central

Eriksson, Tobias J. R.; Laws, Michael; Kang, Lei; Fan, Yichao; Ramadas, Sivaram N.; Dixon, Steve

2016-01-01

Three designs for electrodynamic flexural transducers (EDFT) for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL) above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio (SNR)≃15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart. PMID:27571075

Non-planar pad-printed thick-film focused high-frequency ultrasonic transducers for imaging and therapeutic applications.

PubMed

Lethiecq, Marc; Lou-Moeller, Rasmus; Ketterling, Jeffrey; Levassort, Franck; Tran-Huu-Hue, Louis Pascal; Filoux, Erwan; Silverman, Ronald H; Wolny, Wanda W

2012-09-01

Pad-printed thick-film transducers have been shown to be an interesting alternative to lapped bulk piezoceramics, because the film is deposited with the required thickness, size, and geometry, thus avoiding any subsequent machining to achieve geometrical focusing. Their electromechanical properties are close to those of bulk ceramics with similar composition despite having a higher porosity. In this paper, padprinted high-frequency transducers based on a low-loss piezoceramic composition are designed and fabricated. High-porosity ceramic cylinders with a spherical top surface are used as the backing substrate. The transducers are characterized in view of imaging applications and their imaging capabilities are evaluated with phantoms containing spherical inclusions and in different biological tissues. In addition, the transducers are evaluated for their capability to produce high-acoustic intensities at frequencies around 20 MHz. High-intensity measurements, obtained with a calibrated hydrophone, show that transducer performance is promising for applications that would require the same device to be used for imaging and for therapy. Nevertheless, the transducer design can be improved, and simulation studies are performed to find a better compromise between low-power and high-power performance. The size, geometry, and constitutive materials of optimized configurations are proposed and their feasibility is discussed.

Electromagnetic acoustic transducer

DOEpatents

Alers, George A.; Burns, Jr., Leigh R.; MacLauchlan, Daniel T.

1988-01-01

A noncontact ultrasonic transducer for studying the acoustic properties of a metal workpiece includes a generally planar magnetizing coil positioned above the surface of the workpiece, and a generally planar eddy current coil between the magnetizing coil and the workpiece. When a large current is passed through the magnetizing coil, a large magnetic field is applied to the near-surface regions of the workpiece. The eddy current coil can then be operated as a transmitter by passing an alternating current therethrough to excite ultrasonic waves in the surface of the workpiece, or operated as a passive receiver to sense ultrasonic waves in the surface by measuring the output signal. The geometries of the two coils can be varied widely to be effective for different types of ultrasonic waves. The coils are preferably packaged in a housing which does not interfere with their operation, but protects them from a variety of adverse environmental conditions.

High precision, fast ultrasonic thermometer based on measurement of the speed of sound in air

NASA Astrophysics Data System (ADS)

Huang, K. N.; Huang, C. F.; Li, Y. C.; Young, M. S.

2002-11-01

This study presents a microcomputer-based ultrasonic system which measures air temperature by detecting variations in the speed of sound in the air. Changes in the speed of sound are detected by phase shift variations of a 40 kHz continuous ultrasonic wave. In a test embodiment, two 40 kHz ultrasonic transducers are set face to face at a constant distance. Phase angle differences between transmitted and received signals are determined by a FPGA digital phase detector and then analyzed in an 89C51 single-chip microcomputer. Temperature is calculated and then sent to a LCD display and, optionally, to a PC. Accuracy of measurement is within 0.05 degC at an inter-transducer distance of 10 cm. Temperature variations are displayed within 10 ms. The main advantages of the proposed system are high resolution, rapid temperature measurement, noncontact measurement and easy implementation.

Flexible ultrasonic pipe inspection apparatus

DOEpatents

Jenkins, C.F.; Howard, B.D.

1998-06-23

A flexible, modular ultrasonic pipe inspection apparatus, comprises a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present. 7 figs.

Apparatus and method for ultrasonic reconstruction and testing of a turbine rotor blade attachment structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabourin, P.F.

1995-04-25

An apparatus and method for ultrasonic reconstruction and testing of a non-visible turbine rotor blade attachment structure is described. The method of the invention includes positioning transducers at a first location to obtain slot region scan data corresponding to a slot region of the non-visible turbine rotor blade attachment structure, and positioning transducers at a second location to obtain straddle-mount region scan data corresponding to a straddle-mount region of the non-visible turbine rotor blade attachment structure. The shape of the non-visible turbine rotor blade attachment structure is reconstructed from the slot region scan data and the straddle-mount region scan datamore » to form reconstruction data. The reconstruction data is used to select test scan positions for ultrasonic testing. Ultrasonic testing is then performed at the selected test scan positions. 11 figs.« less

Flexible ultrasonic pipe inspection apparatus

DOEpatents

Jenkins, Charles F.; Howard, Boyd D.

1998-01-01

A flexible, modular ultrasonic pipe inspection apparatus, comprising a flexible, hollow shaft that carries a plurality of modules, including at least one rotatable ultrasonic transducer, a motor/gear unit, and a position/signal encoder. The modules are connected by flexible knuckle joints that allow each module of the apparatus to change its relative orientation with respect to a neighboring module, while the shaft protects electrical wiring from kinking or buckling while the apparatus moves around a tight corner. The apparatus is moved through a pipe by any suitable means, including a tether or drawstring attached to the nose or tail, differential hydraulic pressure, or a pipe pig. The rotational speed of the ultrasonic transducer and the forward velocity of the apparatus are coordinated so that the beam sweeps out the entire interior surface of the pipe, enabling the operator to accurately assess the condition of the pipe wall and determine whether or not leak-prone corrosion damage is present.

Process for Nondestructive Evaluation of the Quality of a Crimped Wire Connector

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Cramer, Karl E. (Inventor); Perey, Daniel F. (Inventor); Williams, Keith A. (Inventor)

2014-01-01

A process and apparatus for collecting data for nondestructive evaluation of the quality of a crimped wire connector are provided. The process involves providing a crimping tool having an anvil and opposing jaw for crimping a terminal onto a stranded wire, moving the jaw relative to the anvil to close the distance between the jaw and the anvil and thereby compress the terminal against the wire, while transmitting ultrasonic waves that are propagated through the terminal-wire combination and received at a receiving ultrasonic transducer as the jaw is moved relative to the anvil, and detecting and recording the position of the jaw relative to the anvil as a function of time and detecting and recording the amplitude of the ultrasonic wave that is received at the receiving ultrasonic transducer as a function of time as the jaw is moved relative to the anvil.

Using Piezoelectric Devices to Transmit Power through Walls

NASA Technical Reports Server (NTRS)

Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi

2008-01-01

A method denoted wireless acoustic-electric feed-through (WAEF) has been conceived for transmitting power and/or data signals through walls or other solid objects made of a variety of elastic materials that could be electrically conductive or nonconductive. WAEF would make it unnecessary to use wires, optical fibers, tubes, or other discrete wall-penetrating signal-transmitting components, thereby eliminating the potential for structural weakening or leakage at such penetrations. Avoidance of such penetrations could be essential in some applications in which maintenance of pressure, vacuum, or chemical or biological isolation is required. In a basic WAEF setup, a transmitting piezoelectric transducer on one side of a wall would be driven at resonance to excite ultrasonic vibrations in the wall. A receiving piezoelectric transducer on the opposite side of the wall would convert the vibrations back to an ultrasonic AC electric signal, which would then be detected and otherwise processed in a manner that would depend on the modulation (if any) applied to the signal and whether the signal was used to transmit power, data, or both. An electromechanical-network model has been derived as a computationally efficient means of analyzing and designing a WAEF system. This model is a variant of a prior model, known in the piezoelectric-transducer art as Mason's equivalent-circuit model, in which the electrical and mechanical dynamics, including electromechanical couplings, are expressed as electrical circuit elements that can include inductors, capacitors, and lumped-parameter complex impedances. The real parts of the complex impedances are used to account for dielectric, mechanical, and coupling losses in all components (including all piezoelectric-transducer, wall, and intermediate material layers). In an application to a three-layer piezoelectric structure, this model was shown to yield the same results as do solutions of the wave equations of piezoelectricity and acoustic propagation in their full complexity.

The Influence of Finite-size Sources in Acousto-ultrasonics

NASA Technical Reports Server (NTRS)

Pavlakovic, Brian N.; Rose, Joseph L.

1994-01-01

This work explores the effects that the finite normal axisymmetric traction loading of an infinite isotropic plate has on wave propagation in acousto-ultrasonics (AU), in which guided waves are created using two normal incidence transducers. Although the work also addresses the effects of the transducer pressure distribution and pulse shape, this thesis concentrates on two main questions: how does the transducer's diameter control the phase velocity and frequency spectrum of the response, and how does the plate thickness relate to the plate's excitability? The mathematics of the time-harmonic solution and the physical principles and the practical considerations for AU wave generation are explained. Transient sources are modeled by the linear superposition of the time-harmonic solutions found using the Hankel transform and they are then compared to experimental data to provide insight into the relation between the size of the transducer and the preferred phase velocity.

A rectangle-type linear ultrasonic motor using longitudinal vibration transducers with four driving feet.

PubMed

Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

2013-04-01

To make full use of the vibrational energy of a longitudinal transducer, a rectangle-type linear ultrasonic motor with four driving feet is proposed in this paper. This new motor consists of four longitudinal vibration transducers which are arranged in a rectangle and form an enclosed construction. Lead zirconate titanate ceramics are embedded into the middle of the transducer and fastened by a wedge-caulking mechanism. Each transducer includes an exponentially shaped horn located on each end. The horns of the vertical transducers intersect at the base of the horizontal transducers' horns; the tip ends of the horizontal transducers' horns are used as the driving feet. Longitudinal vibrations are superimposed in the motor and generate elliptical movements at the tip ends of the horns. The working principle of the proposed motor is analyzed. The resonance frequencies of two working modes are tuned to be close to each other by adjusting the structural parameters. Transient analysis is developed to gain the vibration characteristics of the motor. A prototype motor is fabricated and measured. The vibration test results verify the feasibility of the proposed design. Typical output of the prototype is a no-load speed of 928 mm/s and maximum thrust force of 60 N at a voltage of 200 Vrms.

Ultrasonic detection of knots, cross grain and bark pockets in wooden pallet parts

Treesearch

Mohammed F. Kabir; Daniel L. Schmoldt; Mark E. Schafer

2000-01-01

This study investigates defect detection in wooden pallet parts using ultrasonic scanning. Yellow-poplar (Liriodendron tulipifera, L.) deckboards were scanned using two rolling transducers in a pitch-catch arrangement to detect unsound and sound knots, bark pockets and cross grain. Data were collected, stored, and processed using LabView? software. Six ultrasonic...

Experimental Study on Ultrasonic Computed Tomography Using Transducers Arrayed on the Internal Surface of a Cylinder

NASA Astrophysics Data System (ADS)

Kim, Jung-Soon; Kim, Moo-Joon; Kim, Jung-Ho; Ha, Kang-Lyeol

2005-06-01

In this study, ultrasonic array transducers with 32 vibrators arranged on the internal surface of a part of a cylinder were fabricated. The vibrators were operated by the piezoelectric transverse effect. By controlling the phase of the input signal for every vibrator, a quasi plane wave was synthesized. Using the fabricated array, inverse scattering ultrasonic computed tomography (UCT) was carried out with a phantom specimen after checking the plane wave generation. It was confirmed that the plane wave was synthesized successfully and a sound velocity image of the phantom was obtained by the plane wave. Consequently, it was noted that the array could be employed as a transmitter and receiver for data acquisition in UCT.

Apparatus for ultrasonic nebulization

DOEpatents

Olson, Kenneth W.; Haas, Jr., William J.; Fassel, Velmer A.

1978-08-29

An improved apparatus for ultrasonic nebulization of liquid samples or suspensions in which the piezoelectric transducer is protected from chemical attack and erosion. The transducer is protected by being bonded to the inner surface of a glass plate which forms one end wall of a first hollow body provided with apparatus for circulating a fluid for cooling and stabilizing the transducer. The glass plate, which is one-half wavelength in thickness to provide an acoustically coupled outer nebulizing surface, seals an opening in a second hollow body which encloses an aerosol mixing chamber. The second body includes apparatus for delivering the sample solution to the nebulizing surface, a gas inlet for providing a flow of carrier gas for transporting the aerosol of the nebulized sample and an aerosol outlet.

A robust approach to optimal matched filter design in ultrasonic non-destructive evaluation (NDE)

NASA Astrophysics Data System (ADS)

Li, Minghui; Hayward, Gordon

2017-02-01

The matched filter was demonstrated to be a powerful yet efficient technique to enhance defect detection and imaging in ultrasonic non-destructive evaluation (NDE) of coarse grain materials, provided that the filter was properly designed and optimized. In the literature, in order to accurately approximate the defect echoes, the design utilized the real excitation signals, which made it time consuming and less straightforward to implement in practice. In this paper, we present a more robust and flexible approach to optimal matched filter design using the simulated excitation signals, and the control parameters are chosen and optimized based on the real scenario of array transducer, transmitter-receiver system response, and the test sample, as a result, the filter response is optimized and depends on the material characteristics. Experiments on industrial samples are conducted and the results confirm the great benefits of the method.

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review

PubMed Central

Zhang, Shujun; Li, Fei; Jiang, Xiaoning; Kim, Jinwook; Luo, Jun; Geng, Xuecang

2014-01-01

Relaxor-PbTiO3 (PT) based ferroelectric crystals with the perovskite structure have been investigated over the last few decades due to their ultrahigh piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 90%), far outperforming state-of-the-art ferroelectric polycrystalline Pb(Zr,Ti)O3 ceramics, and are at the forefront of advanced electroacoustic applications. In this review, the performance merits of relaxor-PT crystals in various electroacoustic devices are presented from a piezoelectric material viewpoint. Opportunities come from not only the ultrahigh properties, specifically coupling and piezoelectric coefficients, but through novel vibration modes and crystallographic/domain engineering. Figure of merits (FOMs) of crystals with various compositions and phases were established for various applications, including medical ultrasonic transducers, underwater transducers, acoustic sensors and tweezers. For each device application, recent developments in relaxor-PT ferroelectric crystals were surveyed and compared with state-of-the-art polycrystalline piezoelectrics, with an emphasis on their strong anisotropic features and crystallographic uniqueness, including engineered domain - property relationships. This review starts with an introduction on electroacoustic transducers and the history of piezoelectric materials. The development of the high performance relaxor-PT single crystals, with a focus on their uniqueness in transducer applications, is then discussed. In the third part, various FOMs of piezoelectric materials for a wide range of ultrasound applications, including diagnostic ultrasound, therapeutic ultrasound, underwater acoustic and passive sensors, tactile sensors and acoustic tweezers, are evaluated to provide a thorough understanding of the materials’ behavior under operational conditions. Structure-property-performance relationships are then established. Finally, the impacts and challenges of relaxor-PT crystals are summarized to guide on-going and future research in the development of relaxor-PT crystals for the next generation electroacoustic transducers. PMID:25530641

Ultrasonic scanning system for in-place inspection of brazed-tube joints

NASA Technical Reports Server (NTRS)

Haralson, H. S.; Haynes, J. L.; Wages, C. G.

1971-01-01

System detects defects of .051 cm in diameter and larger. System incorporates scanning head assembly including boot enclosed transducer, slip ring assembly, drive mechanism, and servotransmitter. Ultrasonic flaw detector, prototype recorder, and special recorder complete system.

Minimization of thickness of ultrasonic transducer by using piezoelectric backing layer

NASA Astrophysics Data System (ADS)

Yeom, Jiyoung; Kim, Jungsoon; Ha, Kanglyeol; Kim, Moojoon

2018-07-01

To realize an insertion transducer with broadband characteristic, a transducer with a piezoelectric backing layer is proposed. The characteristic of the transducer was analyzed by using an equivalent circuit for a different electrical impedance connected to the piezoelectric backing layer. In the transducer designed to achieve optimization, the thickness of the transducer is less than 2.4 times that of the driving piezoelectric layer, and the frequency bandwidth is more than 110%. It is confirmed that the bandwidth of the fabricated transducer can be controlled by adjusting the electrical impedance in the piezoelectric backing layer.

In-situ monitoring of acoustic linear and nonlinear behavior of titanium alloys during cycling loading

NASA Astrophysics Data System (ADS)

Frouin, Jerome; Matikas, Theodore E.; Na, Jeong K.; Sathish, Shamachary

1999-02-01

An in-situ technique to measure sound velocity, ultrasonic attenuation and acoustic nonlinear property has been developed for characterization and early detection of fatigue damage in aerospace materials. A previous experiment using the f-2f technique on Ti-6Al-4V dog bone specimen fatigued at different stage of fatigue has shown that the material nonlinearity exhibit large change compared to the other ultrasonic parameter. Real-time monitoring of the nonlinearity may be a future tool to characterize early fatigue damage in the material. For this purpose we have developed a computer software and measurement technique including hardware for the automation of the measurement. New transducer holder and special grips are designed. The automation has allowed us to test the long-term stability of the electronics over a period of time and so proof of the linearity of the system. For the first time, a real-time experiment has been performed on a dog-bone specimen from zero fatigue al the way to the final fracture.

Aligned carbon nanotube based ultrasonic microtransducers for durability monitoring in civil engineering.

PubMed

Lebental, B; Chainais, P; Chenevier, P; Chevalier, N; Delevoye, E; Fabbri, J-M; Nicoletti, S; Renaux, P; Ghis, A

2011-09-30

Structural health monitoring of porous materials such as concrete is becoming a major component in our resource-limited economy, as it conditions durable exploitation of existing facilities. Durability in porous materials depends on nanoscale features which need to be monitored in situ with nanometric resolution. To address this problem, we put forward an approach based on the development of a new nanosensor, namely a capacitive micrometric ultrasonic transducer whose vibrating membrane is made of aligned single-walled carbon nanotubes (SWNT). Such sensors are meant to be embedded in large numbers within a porous material in order to provide information on its durability by monitoring in situ neighboring individual micropores. In the present paper, we report on the feasibility of the key building block of the proposed sensor: we have fabricated well-aligned, ultra-thin, dense SWNT membranes that show above-nanometer amplitudes of vibration over a large range of frequencies spanning from 100 kHz to 5 MHz.

Cost-effective broad-band electrical impedance spectroscopy measurement circuit and signal analysis for piezo-materials and ultrasound transducers

PubMed Central

Lewis, George K; Lewis, George K; Olbricht, William

2008-01-01

This paper explains the circuitry and signal processing to perform electrical impedance spectroscopy on piezoelectric materials and ultrasound transducers. Here, we measure and compare the impedance spectra of 2−5 MHz piezoelectrics, but the methodology applies for 700 kHz–20 MHz ultrasonic devices as well. Using a 12 ns wide 5 volt pulsing circuit as an impulse, we determine the electrical impedance curves experimentally using Ohm's law and fast Fourier transform (FFT), and compare results with mathematical models. The method allows for rapid impedance measurement for a range of frequencies using a narrow input pulse, digital oscilloscope and FFT techniques. The technique compares well to current methodologies such as network and impedance analyzers while providing additional versatility in the electrical impedance measurement. The technique is theoretically simple, easy to implement and completed with ordinary laboratory instrumentation for minimal cost. PMID:19081773

An original approach to elastic constants determination using a self-developed EMAT system

NASA Astrophysics Data System (ADS)

Jenot, Frédéric; Rivart, Frédéric; Camus, Liévin

2018-04-01

Electromagnetic Acoustic Transducers (EMATs) allow non-contact ultrasonic measurements in order to characterize structures for a wide range of applications. Considering non-ferromagnetic metal materials, excitation of elastic waves is due to Lorentz forces that result from an applied magnetic field and induced eddy currents in a near surface region of the sample. EMAT's design is based on a magnet structure associated with a coil leading to multiple configurations, which are able to excite bulk and guided acoustic waves. In this work, we first present a self-developed EMAT system composed of multiple emission and reception channels. In a second part, we propose an original method in order to determine the elastic constants of an isotropic material. To achieve this goal, Rayleigh and shear waves are used and the advantages of this method are clearly highlighted. The results obtained are then compared with conventional measurements achieved with piezoelectric transducers.

Application of ultrasound in periodontics: Part I

PubMed Central

Bains, Vive K.; Mohan, Ranjana; Bains, Rhythm

2008-01-01

Ultrasonic is a branch of acoustics concerned with sound vibrations in frequency ranges above audible level. Ultrasound uses the transmission and reflection of acoustic energy. A pulse is propagated and its reflection is received, both by the transducer. For clinical purposes ultrasound is generated by transducers, which converts electrical energy into ultrasonic waves. This is usually achieved by magnetostriction or piezoelectricity. Primary effects of ultrasound are thermal, mechanical (cavitation and microstreaming), and chemical (sonochemicals). Knowledge of the basic and other secondary effects of ultrasound is essential for the development of techniques of application. PMID:20142941

Hydrodynamic ultrasonic probe

DOEpatents

Day, Robert A.; Conti, Armond E.

1980-01-01

An improved probe for in-service ultrasonic inspection of long lengths of a workpiece, such as small diameter tubing from the interior. The improved probe utilizes a conventional transducer or transducers configured to inspect the tubing for flaws and/or wall thickness variations. The probe utilizes a hydraulic technique, in place of the conventional mechanical guides or bushings, which allows the probe to move rectilinearly or rotationally while preventing cocking thereof in the tube and provides damping vibration of the probe. The probe thus has lower friction and higher inspection speed than presently known probes.

Elastic wave field computation in multilayered nonplanar solid structures: a mesh-free semianalytical approach.

PubMed

Banerjee, Sourav; Kundu, Tribikram

2008-03-01

Multilayered solid structures made of isotropic, transversely isotropic, or general anisotropic materials are frequently used in aerospace, mechanical, and civil structures. Ultrasonic fields developed in such structures by finite size transducers simulating actual experiments in laboratories or in the field have not been rigorously studied. Several attempts to compute the ultrasonic field inside solid media have been made based on approximate paraxial methods like the classical ray tracing and multi-Gaussian beam models. These approximate methods have several limitations. A new semianalytical method is adopted in this article to model elastic wave field in multilayered solid structures with planar or nonplanar interfaces generated by finite size transducers. A general formulation good for both isotropic and anisotropic solids is presented in this article. A variety of conditions have been incorporated in the formulation including irregularities at the interfaces. The method presented here requires frequency domain displacement and stress Green's functions. Due to the presence of different materials in the problem geometry various elastodynamic Green's functions for different materials are used in the formulation. Expressions of displacement and stress Green's functions for isotropic and anisotropic solids as well as for the fluid media are presented. Computed results are verified by checking the stress and displacement continuity conditions across the interface of two different solids of a bimetal plate and investigating if the results for a corrugated plate with very small corrugation match with the flat plate results.

Energy transfer model and its applications of ultrasonic gas flow-meter under static and dynamic flow rates

NASA Astrophysics Data System (ADS)

Fang, Min; Xu, Ke-Jun; Zhu, Wen-Jiao; Shen, Zi-Wen

2016-01-01

Most of the ultrasonic gas flow-meters measure the gas flow rate by calculating the ultrasonic transmission time difference between the downstream and upstream. Ultrasonic energy attenuation occurs in the processes of the ultrasonic generation, conversion, transmission, and reception. Additionally, at the same time, the gas flow will also affect the ultrasonic propagation during the measurement, which results in the ultrasonic energy attenuation and the offset of ultrasonic propagation path. Thus, the ultrasonic energy received by the transducer is weaker. When the gas flow rate increases, this effect becomes more apparent. It leads to the measurement accuracy reduced, and the measurement range narrowed. An energy transfer model, where the ultrasonic gas flow-meter under without/with the gas flow, is established by adopting the statistical analysis and curve fitting based on a large amount of experimental data. The static sub model without the gas flow expresses the energy conversion efficiency of ultrasonic gas transducers, and the dynamic sub model with the gas flow reflects the energy attenuation pattern following the flow rate variations. The mathematical model can be used to determine the minimum energy of the excitation signal for meeting the requirement of specific measurement range, and predict the maximum measurable flow rate in the case of fixed energy of excitation signal. Based on the above studies, a method to enhance the excitation signal energy is proposed under the output power of the transmitting circuit being a finite value so as to extend the measurement rage of ultrasonic gas flow-meter.

A novel ultrasonic aerosol generator.

PubMed

Davies, A; Hudson, N; Pirie, L

1995-07-01

An ultrasonic aerosol generator constructed from a domestic humidifier is described which has been used to produce liquid aerosols for physiological investigations. The instrument was constructed from a Pifco domestic humidifier modified to include an energy guide to direct the oscillations of the transducer through the coupling water, which would normally be aerosolized, onto a small membrane based sample chamber containing the liquid to be aerosolized. The size distribution of the aerosol produced was found to be between 2 and 6 mm, optimum for diffuse intrapulmonary deposition. Up to 4 ml/min of aqueous liquid was used; however the sample chamber could be made small enough to contain economic amounts of expensive material to administer by inhalation. The instrument has proved to be reliable over a period of three years.

Ultrasonic fingerprinting by phased array transducer

NASA Astrophysics Data System (ADS)

Sednev, D.; Kataeva, O.; Abramets, V.; Pushenko, P.; Tverdokhlebova, T.

2016-06-01

Increasing quantity of spent nuclear fuel that must be under national and international control requires a novel approach to safeguard techniques and equipment. One of the proposed approaches is utilize intrinsic features of casks with spent fuel. In this article an application of a phased array ultrasonic method is considered. This study describes an experimental results on ultrasonic fingerprinting of austenitic steel seam weld.

Crossed SMPS MOSFET-based protection circuit for high frequency ultrasound transceivers and transducers.

PubMed

Choi, Hojong; Shung, K Kirk

2014-06-12

The ultrasonic transducer is one of the core components of ultrasound systems, and the transducer's sensitivity is significantly related the loss of electronic components such as the transmitter, receiver, and protection circuit. In an ultrasonic device, protection circuits are commonly used to isolate the electrical noise between an ultrasound transmitter and transducer and to minimize unwanted discharged pulses in order to protect the ultrasound receiver. However, the performance of the protection circuit and transceiver obviously degrade as the operating frequency or voltage increases. We therefore developed a crossed SMPS (Switching Mode Power Supply) MOSFET-based protection circuit in order to maximize the sensitivity of high frequency transducers in ultrasound systems.The high frequency pulse signals need to trigger the transducer, and high frequency pulse signals must be received by the transducer. We therefore selected the SMPS MOSFET, which is the main component of the protection circuit, to minimize the loss in high frequency operation. The crossed configuration of the protection circuit can drive balanced bipolar high voltage signals from the pulser and transfer the balanced low voltage echo signals from the transducer. The equivalent circuit models of the SMPS MOSFET-based protection circuit are shown in order to select the proper device components. The schematic diagram and operation mechanism of the protection circuit is provided to show how the protection circuit is constructed. The P-Spice circuit simulation was also performed in order to estimate the performance of the crossed MOSFET-based protection circuit. We compared the performance of our crossed SMPS MOSFET-based protection circuit with a commercial diode-based protection circuit. At 60 MHz, our expander and limiter circuits have lower insertion loss than the commercial diode-based circuits. The pulse-echo test is typical method to evaluate the sensitivity of ultrasonic transducers. Therefore, we performed a pulse-echo test using a single element transducer in order to utilize the crossed SMPS MOSFET-based protection circuit in an ultrasound system. The SMPS-based protection circuit could be a viable alternative that provides better sensitivity, especially for high frequency ultrasound applications.

Design of ultrasonic attenuation sensor with focused transmitter for density measurements of a slurry in a large steel pipeline

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenwood, Margaret Stautberg

2015-12-01

To design an ultrasonic sensor to measure the attenuation and density of a slurry carried by a large steel pipeline (diameter up to 70 cm) is the goal of this research. The pitch-catch attenuation sensor, placed in a small section of the pipeline, contains a send unit with a focused transducer that focuses the ultrasound to a small region of the receive unit on the opposite wall. The focused transducer consists of a section of a sphere (base ~12 cm) on the outer side of the send unit and a 500 kHz piezoelectric shell of PZT5A epoxied to it. Themore » Rayleigh surface integral is used to calculate the pressure in steel and in water (slurry). An incremental method to plot the paths of ultrasonic rays shows that the rays focus where expected. Further, there is a region where the parallel rays are perpendicular to the wall of the receive unit. Designs for pipeline diameters of 25 cm and 71 cm show that the pressure in water at the receive transducer is about 17 times that for a pitch-catch system using 5 cm diameter disk transducers. The enhanced signal increases the sensitivity of the measurements and improves the signal-to-noise ratio.« less

Development of Integrated Preamplifier for High-Frequency Ultrasonic Transducers and Low-Power Handheld Receiver

PubMed Central

Choi, Hojong; Li, Xiang; Lau, Sien-Ting; Hu, ChangHong; Zhou, Qifa; Shung, K. Kirk

2012-01-01

This paper describes the design of a front-end circuit consisting of an integrated preamplifier with a Sallen-Key Butterworth filter for very-high-frequency ultrasonic transducers and a low-power handheld receiver. This preamplifier was fabricated using a 0.18-μm 7WL SiGe bi-polar complementary metal oxide semiconductor (BiCMOS) process. The Sallen-Key filter is used to increase the voltage gain of the front-end circuit for high-frequency transducers which are generally low in sensitivity. The measured peak voltage gain of the frontend circuits for the BiCMOS preamplifier with the Sallen-Key filter was 41.28 dB at 100 MHz with a −6-dB bandwidth of 91%, and the dc power consumption of the BiCMOS preamplifier was 49.53 mW. The peak voltage gain of the front-end circuits for the CMOS preamplifier with the Sallen-Key filter was 39.52 dB at 100 MHz with a −6-dB bandwidth of 108%, and the dc power consumption of the CMOS preamplifier was 43.57 mW. Pulse-echo responses and wire phantom images with a single-element ultrasonic transducer have been acquired to demonstrate the performance of the front-end circuit. PMID:23443700

Design of ultrasonic attenuation sensor with focused transmitter for density measurements of a slurry in a large steel pipeline.

PubMed

Greenwood, Margaret Stautberg

2015-12-01

To design an ultrasonic sensor to measure the attenuation and density of slurry carried by a large steel pipeline (diameter up to 70 cm) is the goal of this research. The pitch-catch attenuation sensor, placed in a small section of the pipeline, contains a send unit with a focused transducer that focuses the ultrasound to a small region of the receive unit on the opposite wall. The focused transducer consists of a section of a sphere (base ∼12 cm) on the outer side of the send unit and a 500 kHz piezoelectric shell of lead zirconate titanate epoxied to it. The Rayleigh surface integral is used to calculate the pressure in steel and in water (slurry). An incremental method to plot the paths of ultrasonic rays shows that the rays focus where expected. Further, there is a region where the parallel rays are perpendicular to the wall of the receive unit. Designs for pipeline diameters of 25 and 71 cm show that the pressure in water at the receive transducer is about 17 times that for a pitch-catch system using 5 cm diameter disk transducers. The enhanced signal increases the sensitivity of the measurements and improves the signal-to-noise ratio.

In vivo microwave-based thermoacoustic tomography of rats (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lin, Li; Zhou, Yong; Wang, Lihong V.

2016-03-01

Microwave-based thermoacoustic tomography (TAT), based on the measurement of ultrasonic waves induced by microwave pulses, can reveal tissue dielectric properties that may be closely related to the physiological and pathological status of the tissues. Using microwaves as the excitation source improved imaging depth because of their deep penetration into biological tissues. We demonstrate, for the first time, in vivo microwave-based thermoacoustic imaging in rats. The transducer is rotated around the rat in a full circle, providing a full two-dimensional view. Instead of a flat ultrasonic transducer, we used a virtual line detector based on a cylindrically focused transducer. A 3 GHz microwave source with 0.6 µs pulse width and an electromagnetically shielded transducer with 2.25 MHz central frequency provided clear cross-sectional images of the rat's body. The high imaging contrast, based on the tissue's rate of absorption, and the ultrasonically defined spatial resolution combine to reveal the spine, kidney, muscle, and other deeply seated anatomical features in the rat's abdominal cavity. This non-invasive and non-ionizing imaging modality achieved an imaging depth beyond 6 cm in the rat's tissue. Cancer diagnosis based on information about tissue properties from microwave band TAT can potentially be more accurate than has previously been achievable.

Novel Real-Time Temperature Diagnosis of Conventional Hot-Embossing Process Using an Ultrasonic Transducer

PubMed Central

Cheng, Chin-Chi; Yang, Sen-Yeu; Lee, Dasheng

2014-01-01

This paper presents an integrated high temperature ultrasonic transducer (HTUT) on a sensor insert and its application for real-time diagnostics of the conventional hot embossing process to fabricate V-cut patterns. The sensor was directly deposited onto the sensor insert of the hot embossing mold by using a sol-gel spray technique. It could operate at temperatures higher than 400 °C and uses an ultrasonic pulse-echo technique. The ultrasonic velocity could indicate the three statuses of the hot embossing process and also evaluate the replication of V-cut patterns on a plastic plate under various processing conditions. The progression of the process, including mold closure, plastic plate softening, cooling and plate detachment inside the mold, was clearly observed using ultrasound. For an ultrasonic velocity range from 2197.4 to 2435.9 m/s, the height of the V-cut pattern decreased from 23.0 to 3.2 μm linearly, with a ratio of −0.078 μm/(m/s). The incompleteness of the replication of the V-cut patterns could be indirectly observed by the ultrasonic signals. This study demonstrates the effectiveness of the ultrasonic sensors and technology for diagnosing the replicating condition of microstructures during the conventional hot embossing process. PMID:25330051

Application of electromagnetic-acoustic transducers for nondestructive testing in steel bridge structures.

DOT National Transportation Integrated Search

1996-01-01

This report presents the results of a study to (1) assess the applicability of electromagnetic-acoustic transducers for nondestructive evaluation of stresses in bridge structures and (2) evaluate the new ultrasonic instruments as an effective techniq...

Losses in Ferroelectric Materials

PubMed Central

Liu, Gang; Zhang, Shujun; Jiang, Wenhua; Cao, Wenwu

2015-01-01

Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy loss mechanisms are discussed in terms of compositions, crystal structures, temperature, domain configurations, domain sizes and grain boundaries. The intrinsic and extrinsic contributions to the total energy dissipation are quantified. In domain engineered ferroelectric single crystals and ceramics, polarization rotations, domain wall motions and mechanical wave scatterings at grain boundaries are believed to control the mechanical quality factors of piezoelectric resonators. We show that a thorough understanding on the kinetic processes is critical in analyzing energy loss behavior and other time-dependent properties in ferroelectric materials. At the end of the review, existing challenges in the study and control of losses in ferroelectric materials are analyzed, and future perspective in resolving these issues is discussed. PMID:25814784

Losses in Ferroelectric Materials.

PubMed

Liu, Gang; Zhang, Shujun; Jiang, Wenhua; Cao, Wenwu

2015-03-01

Ferroelectric materials are the best dielectric and piezoelectric materials known today. Since the discovery of barium titanate in the 1940s, lead zirconate titanate ceramics in the 1950s and relaxor-PT single crystals (such as lead magnesium niobate-lead titanate and lead zinc niobate-lead titanate) in the 1980s and 1990s, perovskite ferroelectric materials have been the dominating piezoelectric materials for electromechanical devices, and are widely used in sensors, actuators and ultrasonic transducers. Energy losses (or energy dissipation) in ferroelectrics are one of the most critical issues for high power devices, such as therapeutic ultrasonic transducers, large displacement actuators, SONAR projectors, and high frequency medical imaging transducers. The losses of ferroelectric materials have three distinct types, i.e., elastic, piezoelectric and dielectric losses. People have been investigating the mechanisms of these losses and are trying hard to control and minimize them so as to reduce performance degradation in electromechanical devices. There are impressive progresses made in the past several decades on this topic, but some confusions still exist. Therefore, a systematic review to define related concepts and clear up confusions is urgently in need. With this objective in mind, we provide here a comprehensive review on the energy losses in ferroelectrics, including related mechanisms, characterization techniques and collections of published data on many ferroelectric materials to provide a useful resource for interested scientists and engineers to design electromechanical devices and to gain a global perspective on the complex physical phenomena involved. More importantly, based on the analysis of available information, we proposed a general theoretical model to describe the inherent relationships among elastic, dielectric, piezoelectric and mechanical losses. For multi-domain ferroelectric single crystals and ceramics, intrinsic and extrinsic energy loss mechanisms are discussed in terms of compositions, crystal structures, temperature, domain configurations, domain sizes and grain boundaries. The intrinsic and extrinsic contributions to the total energy dissipation are quantified. In domain engineered ferroelectric single crystals and ceramics, polarization rotations, domain wall motions and mechanical wave scatterings at grain boundaries are believed to control the mechanical quality factors of piezoelectric resonators. We show that a thorough understanding on the kinetic processes is critical in analyzing energy loss behavior and other time-dependent properties in ferroelectric materials. At the end of the review, existing challenges in the study and control of losses in ferroelectric materials are analyzed, and future perspective in resolving these issues is discussed.

Laser ultrasonics for bulk-density distribution measurement on green ceramic tiles

NASA Astrophysics Data System (ADS)

Revel, G. M.; Cavuto, A.; Pandarese, G.

2016-10-01

In this paper a Laser Ultrasonics (LUT) system is developed and applied to measure bulk density distribution of green ceramic tiles, which are porous materials with low heat conductivity. Bulk density of green ceramic bodies is a fundamental parameter to be kept under control in the industrial production of ceramic tiles. The LUT system proposed is based on a Nd:YAG pulsed laser for excitation and an air-coupled electro-capacitive transducer for detection. The paper reports experimental apparent bulk-density measurements on white ceramic bodies after a calibration procedures. The performances observed are better than those previously achieved by authors using air-coupled ultrasonic probes for both emission and detection, allowing to reduce average uncertainty down to about ±6 kg/m3 (±0.3%), thanks to the increase in excitation efficiency and lateral resolution, while maintaining potential flexibility for on-line application. The laser ultrasonic procedure proposed is available for both on-line and off-line application. In this last case it is possible to obtain bulk density maps with high spatial resolution by a 2D scan without interrupting the production process.

A program to calculate pulse transmission responses through transversely isotropic media

NASA Astrophysics Data System (ADS)

Li, Wei; Schmitt, Douglas R.; Zou, Changchun; Chen, Xiwei

2018-05-01

We provide a program (AOTI2D) to model responses of ultrasonic pulse transmission measurements through arbitrarily oriented transversely isotropic rocks. The program is built with the distributed point source method that treats the transducers as a series of point sources. The response of each point source is calculated according to the ray-tracing theory of elastic plane waves. The program could offer basic wave parameters including phase and group velocities, polarization, anisotropic reflection coefficients and directivity patterns, and model the wave fields, static wave beam, and the observed signals for pulse transmission measurements considering the material's elastic stiffnesses and orientations, sample dimensions, and the size and positions of the transmitters and the receivers. The program could be applied to exhibit the ultrasonic beam behaviors in anisotropic media, such as the skew and diffraction of ultrasonic beams, and analyze its effect on pulse transmission measurements. The program would be a useful tool to help design the experimental configuration and interpret the results of ultrasonic pulse transmission measurements through either isotropic or transversely isotropic rock samples.

Improving the axial resolution in time-reversed ultrasonically encoded (TRUE) optical focusing with dual ultrasonic waves

NASA Astrophysics Data System (ADS)

Yang, Qiang; Xu, Xiao; Lai, Puxiang; Sang, Xinzhu; Wang, Lihong V.

2014-03-01

Focusing light inside highly scattering media beyond the ballistic regime is a challenging task in biomedical optical imaging, manipulation, and therapy. This challenge can be overcome by time reversing ultrasonically encoded (TRUE) diffuse light to the ultrasonic focus inside a turbid medium. In TRUE optical focusing, a photorefractive crystal or polymer is used as the phase conjugate mirror for optical time reversal. Accordingly, a relatively long ultrasound burst, whose duration matches the response time of the photorefractive material, is used to encode the diffuse light. With this long ultrasound burst, the resolution of the TRUE focus along the acoustic axis is poor. In this work, we used two transducers, emitting two intersecting ultrasound beams at 3.4 MHz and 3.6 MHz respectively, to modulate the diffuse light within their intersection volume at the beat frequency. We show that light encoded at the beat frequency can be time-reversed and converge to the intersection volume. Experimentally, TRUE focusing with an acoustic axial resolution of ~1.1 mm was demonstrated inside turbid media, agreeing with the theoretical estimation.

System and technique for characterizing fluids using ultrasonic diffraction grating spectroscopy

DOEpatents

Greenwood, Margaret S.

2005-04-12

A system for determining a property of a fluid based on ultrasonic diffraction grating spectroscopy includes a diffraction grating on a solid in contact with the fluid. An interrogation device delivers ultrasound through the solid and a captures a reflection spectrum from the diffraction grating. The reflection spectrum including a diffraction order equal to zero exhibits a peak whose location is used to determine speed of sound in the fluid. A separate measurement of the acoustic impedance is combined with the determined speed of sound to yield a measure of fluid density. A system for determining acoustic impedance includes an ultrasonic transducer on a first surface of a solid member, and an opposed second surface of the member is in contact with a fluid to be monitored. A longitudinal ultrasonic pulse is delivered through the solid member, and a multiplicity of pulse echoes caused by reflections of the ultrasonic pulse between the solid-fluid interface and the transducer-solid interface are detected. The decay rate of the detected echo amplitude as a function of echo number is used to determine acoustic impedance.

Novel Real-Time Diagnosis of the Freezing Process Using an Ultrasonic Transducer

PubMed Central

Tseng, Yen-Hsiang; Cheng, Chin-Chi; Cheng, Hong-Ping; Lee, Dasheng

2015-01-01

The freezing stage governs several critical parameters of the freeze drying process and the quality of the resulting lyophilized products. This paper presents an integrated ultrasonic transducer (UT) in a stainless steel bottle and its application to real-time diagnostics of the water freezing process. The sensor was directly deposited onto the stainless steel bottle using a sol-gel spray technique. It could operate at temperature range from −100 to 400 °C and uses an ultrasonic pulse-echo technique. The progression of the freezing process, including water-in, freezing point and final phase change of water, were all clearly observed using ultrasound. The ultrasonic signals could indicate the three stages of the freezing process and evaluate the cooling and freezing periods under various processing conditions. The temperature was also adopted for evaluating the cooling and freezing periods. These periods increased with water volume and decreased with shelf temperature (i.e., speed of freezing). This study demonstrates the effectiveness of the ultrasonic sensor and technology for diagnosing and optimizing the process of water freezing to save energy. PMID:25946629

Advanced Recording and Preprocessing of Physiological Signals. [data processing equipment for flow measurement of blood flow by ultrasonics

NASA Technical Reports Server (NTRS)

Bentley, P. B.

1975-01-01

The measurement of the volume flow-rate of blood in an artery or vein requires both an estimate of the flow velocity and its spatial distribution and the corresponding cross-sectional area. Transcutaneous measurements of these parameters can be performed using ultrasonic techniques that are analogous to the measurement of moving objects by use of a radar. Modern digital data recording and preprocessing methods were applied to the measurement of blood-flow velocity by means of the CW Doppler ultrasonic technique. Only the average flow velocity was measured and no distribution or size information was obtained. Evaluations of current flowmeter design and performance, ultrasonic transducer fabrication methods, and other related items are given. The main thrust was the development of effective data-handling and processing methods by application of modern digital techniques. The evaluation resulted in useful improvements in both the flowmeter instrumentation and the ultrasonic transducers. Effective digital processing algorithms that provided enhanced blood-flow measurement accuracy and sensitivity were developed. Block diagrams illustrative of the equipment setup are included.

pMUT+ASIC integrated platform for wide range ultrasonic imaging

NASA Astrophysics Data System (ADS)

Tillak, J.; Saeed, N.; Khazaaleh, S.; Viegas, J.; Yoo, J.

2017-03-01

We propose an integrated platform of Aluminum Nitrate (AlN) based Piezoelectric Micromachined Ultrasonic Transducer (pMUT) phased array with Application Specific Integrated Circuit (ASIC) for medical imaging and industrial diagnosis. The ASIC provides wide driving range for frequencies between 100 kHz and 5 MHz and channelscalable, programmable application adaptive transmitting beamformer. The system supports operation in various media, including gasses, liquids and biological tissue. The scan resolution for 5 MHz operation is 68 μm in air. The beamformer covers a test volume from -30° to +30° with a step of 3° and scan depth of 10 cm. The ASIC system features low noise receiver electronics, power saving transmission circuitry, and high-voltage drive of large capacitance transducer (up to 500 pF). Integrated pMUT phased array consists of 4 channels of single-membrane ultrasonic transducer of 400 nm deflection and 20 pF feed-thru capacitance, which produce 15 Pa pressure at 500 μm distance from the surface of the transducers. The active area of the ASIC is (700×1490) μm2, which includes channel scalable TX, 8-channale low noise RX, digital back end with autonomous beamformer and power management unit. The system is battery powered with 3.3V-5V standard supply, representing a truly portable solution for ultrasonic applications. Given the CMOS-compatible fabrication process for the AlN pMUTs, dense, miniaturized arrays are possible. Furthermore the smooth surface of dielectric AlN renders optical quality MEMS surfaces for integration in miniaturized photonic + ultrasound microsystems.

Receive-Noise Analysis of Capacitive Micromachined Ultrasonic Transducers.

PubMed

Bozkurt, Ayhan; Yaralioglu, G Goksenin

2016-11-01

This paper presents an analysis of thermal (Johnson) noise received from the radiation medium by otherwise noiseless capacitive micromachined ultrasonic transducer (CMUT) membranes operating in their fundamental resonance mode. Determination of thermal noise received by multiple numbers of transducers or a transducer array requires the assessment of cross-coupling through the radiation medium, as well as the self-radiation impedance of the individual transducer. We show that the total thermal noise received by the cells of a CMUT has insignificant correlation, and is independent of the radiation impedance, but is only determined by the mass of each membrane and the electromechanical transformer ratio. The proof is based on the analytical derivations for a simple transducer with two cells, and extended to transducers with numerous cells using circuit simulators. We used a first-order model, which incorporates the fundamental resonance of the CMUT. Noise power is calculated by integrating over the entire spectrum; hence, the presented figures are an upper bound for the noise. The presented analyses are valid for a transimpedance amplifier in the receive path. We use the analysis results to calculate the minimum detectable pressure of a CMUT. We also provide an analysis based on the experimental data to show that output noise power is limited by and comparable to the theoretical upper limit.

Capacitive micromachined ultrasonic transducers (CMUTs) with isolation posts.

PubMed

Huang, Yongli; Zhuang, Xuefeng; Haeggstrom, Edward O; Ergun, A Sanli; Cheng, Ching-Hsiang; Khuri-Yakub, Butrus T

2008-03-01

In this paper, an improved design of a capacitive micromachined ultrasonic transducer (CMUT) is presented. The design improvement aims to address the reliability issues of a CMUT and to extend the device operation beyond the contact (collapse) voltage. The major design novelty is the isolation posts in the vacuum cavities of the CMUT cells instead of full-coverage insulation layers in conventional CMUTs. This eliminates the contact voltage drifting due to charging caused by the insulation layer, and enables repeatable CMUT operation in the post-contact regime. Ultrasonic tests of the CMUTs with isolation posts (PostCMUTs) in air (electrical input impedance and capacitance vs. bias voltage) and immersion (transmission and reception) indicate acoustic performance similar to that obtained from conventional CMUTs while no undesired side effects of this new design is observed.

Development of a bi-directional standing wave linear piezoelectric actuator with four driving feet.

PubMed

Liu, Yingxiang; Shi, Shengjun; Li, Chunhong; Chen, Weishan; Wang, Liang; Liu, Junkao

2018-03-01

A bi-directional standing wave linear piezoelectric ultrasonic actuator with four driving feet is proposed in this work. Two sandwich type transducers operated in longitudinal-bending hybrid modes are set parallelly. The working mode of the transducer is not simple hybrid vibrations of a longitudinal one and a bending one, but a special coupling vibration mode contained both longitudinal and bending components. Two transducers with the same structure and unsymmetrical boundary conditions are set parallelly to accomplish the bi-directional driving: the first transducer can push the runner forward, while the other one produces the backward driving. In the experiments, two voltages with different amplitudes are applied on the two transducers, respectively: the one with higher voltage serves as the actuator, whereas the other one applied with lower voltage is used to reduce the frictional force. The prototype achieves maximum no-load speed and thrust force of 244 mm/s and 9.8 N. This work gives a new idea for the construction of standing wave piezoelectric ultrasonic actuator with bi-directional driving ability. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrasonic phased array controller for hyperthermia applications.

PubMed

Benkeser, P J; Pao, T L; Yoon, Y J

1991-01-01

Multiple and mechanically scanned ultrasound transducer systems have demonstrated the efficacy of using ultrasound to produce deep localized hyperthermia. The use of ultrasonic phased arrays has been proposed as an alternative to these systems. A phased array offers a more flexible approach to heating tumours in that the size, shape, and position of its focal region can be altered during the course of treatment in order to achieve the desired temperature distribution. This added flexibility comes at the cost of increased complexity of the hardware necessary to drive the transducer because each element requires its own amplifer with both phase and amplitude control. In order for phased arrays with large numbers of elements to be feasible for hyperthermia applications, the complexity of this circuitry must be minimized. This paper describes a circuit design which simplifies the electronics required to control a phased array transducer system for hyperthermia applications. The design is capable of controlling virtually any type of phased array transducer operating at frequencies less than 2 MHz. The system performance was verified through beam profile measurements using a 48-element tapered phased array transducer.

Capacitive micromachined ultrasonic transducers for medical imaging and therapy.

PubMed

Khuri-Yakub, Butrus T; Oralkan, Omer

2011-05-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated frontend electronic circuits we developed and their use for 2-D and 3-D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a MEMS technology for many medical diagnostic and therapeutic applications.

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

PubMed Central

Khuri-Yakub, Butrus T.; Oralkan, Ömer

2011-01-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated frontend electronic circuits we developed and their use for 2-D and 3-D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a MEMS technology for many medical diagnostic and therapeutic applications. PMID:21860542

Two-dimensional noncontact transportation of small objects in air using flexural vibration of a plate.

PubMed

Kashima, Ryota; Koyama, Daisuke; Matsukawa, Mami

2015-12-01

This paper investigates a two-dimensional ultrasonic manipulation technique for small objects in air. The ultrasonic levitation system consists of a rectangular vibrating plate with four ultrasonic transducers and a reflector. The configuration of the vibrator, the resonant frequency, and the positions of the four transducers with step horns were determined from finite element analysis such that an intense acoustic standing-wave field could be generated between the plates. A lattice flexural vibration mode with a wavelength of 28.3 mm was excited on the prototype plate at 24.6 kHz. Small objects could get trapped in air along the horizontal nodal plane of the standing wave. By controlling the driving phase difference between the transducers, trapped objects could be transported without contact in a two-dimensional plane. When the phase difference was changed from 0° to 720°, the distance moved by a small particle in the orthogonal direction was approximately 29 mm, which corresponds with the wavelength of the flexural vibration on the vibrating plate.

Ultrasonic model and system for measurement of corneal biomechanical properties and validation on phantoms.

PubMed

Liu, Jun; He, Xiaoyin; Pan, Xueliang; Roberts, Cynthia J

2007-01-01

Non-invasive measurement of biomechanical properties of corneas may provide important information for ocular disease management and therapeutic procedures. An ultrasonic non-destructive evaluation method with a wave propagation model was developed to determine corneal biomechanical properties in vivo. In this study, we tested the feasibility of the approach in differentiating the mechanical properties of soft contact lenses as corneal phantoms. Three material types of soft contact lenses (six samples in each group) were measured using a broadband ultrasound transducer. The ultrasonic reflections from the contact lenses were recorded by a 500MHz/8-bit digitizer, and displayed and processed by a PC. A reference signal was recorded to compute the normalized power spectra using Fast Fourier Transformation. An inverse algorithm based on least-squares minimization was used to reconstruct three parameters of the contact lenses: density, thickness, and elastic constants lambda+2micro. The thickness of each sample was verified using an electronic thickness gauge, and the averaged density for each type of lenses was verified using Archimedes' principle and manufacturer's report. Our results demonstrated that the ultrasonic system was able to differentiate the elastic properties of the three types of the soft contact lenses with statistical significance (P-value<0.001). The reconstructed thicknesses and densities agreed well with the independent measurements. Our studies on corneal phantoms indicated that the ultrasonic system was sensitive and accurate in measuring the material properties of cornea-like structures. It is important to optimize the system for in vivo measurements.

Fabrication of a two-dimensional piezoelectric micromachined ultrasonic transducer array using a top-crossover-to-bottom structure and metal bridge connections

NASA Astrophysics Data System (ADS)

Jung, Joontaek; Kim, Sangwon; Lee, Wonjun; Choi, Hongsoo

2013-12-01

A new design methodology and fabrication process for two-dimensional (2D) piezoelectric micromachined ultrasonic transducer (pMUT) arrays using a top-crossover-to-bottom (TCTB) structure was developed. Individual sensing and actuation of pMUT elements from a small number of connection lines was enabled by the TCTB structure, and the parasitic coupling capacitance of the array was significantly reduced as a result. A 32 × 32 pMUT array with a TCTB structure was fabricated, resulting in 64 connection lines over an area of 4.8 × 4.8 mm2. The top electrodes for each pMUT element were re-connected by metal bridging after bottom-electrode etching caused them to become disconnected. A deep reactive ion etching process was used to compactify the array. Each pMUT element was a circular-shaped K31-type ultrasonic transducer using a 1 µm thick sol-gel lead zirconate titanate (PZT: Pb1.10 Zr0.52 Ti0.48) thin film. To characterize a single element in the 2D pMUT array, the resonant frequency and coupling coefficient of 20 pMUT elements were averaged to 3.85 MHz and 0.0112, respectively. The maximum measured ultrasound intensity in water, measured at a distance of 4 mm, was 4.6 µW cm-2 from a single pMUT element driven by a 5 Vpp sine wave at 2.22 MHz. Potential applications for development of a TCTB-arranged 2D pMUT array include ultrasonic medical imaging, ultrasonic communication, ultrasonic range-finding and handwriting input systems.

Review of progress in quantitative NDE

NASA Astrophysics Data System (ADS)

s of 386 papers and plenary presentations are included. The plenary sessions are related to the national technology initiative. The other sessions covered the following NDE topics: corrosion, electromagnetic arrays, elastic wave scattering and backscattering/noise, civil structures, material properties, holography, shearography, UT wave propagation, eddy currents, coatings, signal processing, radiography, computed tomography, EM imaging, adhesive bonds, NMR, laser ultrasonics, composites, thermal techniques, magnetic measurements, nonlinear acoustics, interface modeling and characterization, UT transducers, new techniques, joined materials, probes and systems, fatigue cracks and fracture, imaging and sizing, NDE in engineering and process control, acoustics of cracks, and sensors. An author index is included.

Ultrasonic sensor and method of use

DOEpatents

Condreva, Kenneth J.

2001-01-01

An ultrasonic sensor system and method of use for measuring transit time though a liquid sample, using one ultrasonic transducer coupled to a precision time interval counter. The timing circuit captures changes in transit time, representing small changes in the velocity of sound transmitted, over necessarily small time intervals (nanoseconds) and uses the transit time changes to identify the presence of non-conforming constituents in the sample.

An Airborne Ultrasonic Imaging System Based on 16 Elements: 150 kHz Piezopolymer Transducer Arrays—Preliminary Simulated and Experimental Results for Cylindrical Targets Detection

NASA Astrophysics Data System (ADS)

Capineri, L.; Bulletti, A.; Calzolai, M.; Giannelli, P.

2016-12-01

This paper describes the design and fabrication of a 16-element transducer array for airborne ultrasonic imaging operating at 150 kHz, that can operate both at close range (50 mm) in the near field of a synthetic aperture, and up to 250 mm. The proposed imaging technique is based on a modified version of the delay and sum algorithm implemented with a synthetic aperture where each pixel amplitude is determined by the integration of the signal obtained by the coherent summation of the acquired signals over a delayed window with fixed length. The image reconstruction methods using raw data provides the possibility to detect targets with smaller feature size on the order of one wavelength because the coherent signals summation over the selected window length while the image reconstruction methods using the summation of enveloped signals increases the amplitude response at the expenses of a lower spatial resolution. For the implementation of this system it is important to design compact airborne transducers with large field of view and this can be obtained with a new design of hemi-cylindrical polyvinylidene fluoride film transducers directly mounted on a printed circuit board. This new method is low cost and has repeatable transducer characteristics. The complete system is compact, with a modular architecture, in which eight boards with dual ultrasonic channels are mounted on a mother board. Each daughter board hosts a microcontroller unit and can operate with transducers in the bandwidth 40-200 kHz with on-board data acquisition, pre-processing and transfer on a dedicated bus.

A new application of PVDF line-focus transducers on measuring dispersion curves of a layered medium

NASA Astrophysics Data System (ADS)

Lee, Yung-Chun; Ko, Shin-Pin

2000-05-01

In the past few years, PVDF line-focus acoustic transducers have been proven to be a useful and convenient tool for accurately measuring surface wave velocity. The transducer is very easy to construct and the measurement system can be readily established with conventional ultrasonic instruments. In this investigation, however, the capability of PVDF line-focus transducers will be further extended to the measurement of dispersion relation of surface acoustic waves of a layered medium. To achieve this, a number of line-focus transducers are first fabricated with PVDF films of various thickness so that they can operate at different frequencies. Experimental testing on these transducers shows that surface acoustic waves of frequency ranging from 2 MHz to 20 MHz can be effectively generated and detected. For the determination of surface wave velocity as a function of frequency, a new method of processing the measured waveforms during a z-direction defocusing measurements is developed. A mathematical model is given to explain how this method works. With the transducers and the analyzing method, the surface wave dispersion relation of a layer/substrate configuration have been experimentally determined. Samples include thick polymeric films as well as metal films deposited on glass, aluminum, and silicon crystal. Possibility of determining material properties of the layers from the measured dispersion curves will be discussed.

Correlating Inertial Acoustic Cavitation Emissions with Material Erosion Resistance

NASA Astrophysics Data System (ADS)

Ibanez, I.; Hodnett, M.; Zeqiri, B.; Frota, M. N.

The standard ASTM G32-10 concerns the hydrodynamic cavitation erosion resistance of materials by subjecting them to acoustic cavitation generated by a sonotrode. The work reported extends this technique by detecting and monitoring the ultrasonic cavitation, considered responsible for the erosion process, specifically for coupons of aluminium-bronze alloy. The study uses a 65 mm diameter variant of NPL's cavitation sensor, which detects broadband acoustic emissions, and logs acoustic signals generated in the MHz frequency range, using NPL's Cavimeter. Cavitation readings were made throughout the exposure duration, which was carried out at discrete intervals (900 to 3600 s), allowing periodic mass measurements to be made to assess erosion loss under a strict protocol. Cavitation measurements and erosion were compared for different separations of the sonotrode tip from the material under test. The maximum variation associated with measurement of cavitation level was between 2.2% and 3.3% when the separation (λ) between the transducer horn and the specimen increased from 0.5 to 1.0 mm, for a transducer (sonotrode) displacement amplitude of 43.5 μm. Experiments conducted at the same transducer displacement amplitude show that the mass loss of the specimen -a measure of erosion- was 67.0 mg (λ = 0.5 mm) and 66.0 mg (λ = 1.0 mm).

A Simple Ultrasonic Experiment Using a Phase Shift Detection Technique.

ERIC Educational Resources Information Center

Yunus, W. Mahmood Mat; Ahmad, Maulana

1996-01-01

Describes a simple ultrasonic experiment that can be used to measure the purity of liquid samples by detecting variations in the velocity of sound. Uses a phase shift detection technique that incorporates the use of logic gates and a piezoelectric transducer. (JRH)

A passively tunable acoustic metamaterial lens for selective ultrasonic excitation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, H.; Semperlotti, F., E-mail: Fabio.Semperlotti.1@nd.edu

2014-09-07

In this paper, we present an approach to ultrasonic beam-forming and beam-steering in structures based on the concept of embedded acoustic metamaterial lenses. The lens design exploits the principle of acoustic drop-channel that enables the dynamic coupling of multiple ultrasonic waveguides at selected frequencies. In contrast with currently available technology, the embedded lens allows exploiting the host structure as a key component of the transducer system therefore enabling directional excitation by means of a single ultrasonic transducer. The design and the performance of the lens are numerically investigated by using Plane Wave Expansion and Finite Difference Time Domain techniques appliedmore » to bulk structures. Then, the design is experimentally validated on a thin aluminum plate waveguide where the lens is implemented by through-holes. The dynamic response of the embedded lens is estimated by reconstructing, via Laser Vibrometry, the velocity field induced by a single source located at the center of the lens.« less

Ultrasonic sensing of GMAW: Laser/EMAT defect detection system. [Gas Metal Arc Welding (GMAW), Electromagnetic acoustic transducer (EMAT)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlson, N.M.; Johnson, J.A.; Larsen, E.D.

1992-01-01

In-process ultrasonic sensing of welding allows detection of weld defects in real time. A noncontacting ultrasonic system is being developed to operate in a production environment. The principal components are a pulsed laser for ultrasound generation and an electromagnetic acoustic transducer (EMAT) for ultrasound reception. A PC-based data acquisition system determines the quality of the weld on a pass-by-pass basis. The laser/EMAT system interrogates the area in the weld volume where defects are most likely to occur. This area of interest is identified by computer calculations on a pass-by-pass basis using weld planning information provided by the off-line programmer. Themore » absence of a signal above the threshold level in the computer-calculated time interval indicates a disruption of the sound path by a defect. The ultrasonic sensor system then provides an input signal to the weld controller about the defect condition. 8 refs.« less

An HDF5-based framework for the distribution and analysis of ultrasonic concrete data

NASA Astrophysics Data System (ADS)

Prince, Luke; Clayton, Dwight; Santos-Villalobos, Hector

2017-02-01

There are many commercial ultrasonic tomography devices (UTDs) available for use in nondestructive evaluation (NDE) of reinforced concrete structures. These devices emit, measure, and store ultrasonic signals typically in the 25 kHz to 5 MHz frequency range. UTDs are characterized by a composition of multiple transducers, also known as a transducer array or phased array. Often, UTDs data are in a proprietary format. Consequently, NDE research data is limited to those who have prior non-disclosure agreements or the appropriate licenses. Thus, there is a need for a proper universal data framework to exist such that proprietary file datasets for different concrete specimens can be converted, organized, and stored with relative metadata for individual or collaborative NDE research. Building upon the Hierarchical Data Format (HDF5) model, we have developed a UTD data management framework and Graphic User Interface (GUI) to promote the algorithmic reconstruction of ultrasonic data in a controlled environment for easily reproducible and publishable results.

An HDF5-Based Framework for the Distribution and Analysis of Ultrasonic Concrete Data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prince, Luke J; Clayton, Dwight A; Santos-Villalobos, Hector J

There are many commercial ultrasonic tomography devices (UTDs) available for use in nondestructive evaluation (NDE) of reinforced concrete structures. These devices emit, measure, and store ultrasonic signals typically in the 25 kHz to 5 MHz frequency range. UTDs are characterized by a composition of multiple transducers, also known as a transducer array or phased array. Often, UTDs data are in a proprietary format. Consequently, NDE research data is limited to those who have prior non-disclosure agreements or the appropriate licenses. Thus, there is a need for a proper universal data framework to exist such that proprietary file datasets for differentmore » concrete specimens can be converted, organized, and stored with relative metadata for individual or collaborative NDE research. Building upon the Hierarchical Data Format (HDF5) model, we have developed a UTD data management framework and Graphic User Interface (GUI) to promote the algorithmic reconstruction of ultrasonic data in a controlled environment for easily reproducible and publishable results.« less

Experiments in ultrasonic flaw detection using a MEMS transducer

NASA Astrophysics Data System (ADS)

Jain, Akash; Greve, David W.; Oppenheim, Irving J.

2003-08-01

In earlier work we developed a MEMS phased array transducer, fabricated in the MUMPs process, and we reported on initial experimental studies in which the device was affixed into contact with solids. We demonstrated the successful detection of signals from a conventional ultrasonic source, and the successful localization of the source in an off-axis geometry using phased array signal processing. We now describe the predicted transmission and coupling characteristics for such devices in contact with solids, demonstrating reasonable agreement with experimental behavior. We then describe the results of flaw detection experiments, as well as results for fluid-coupled detectors.

Optical Production and Detection of Ultrasonic Waves in Metals for Nondestructive Testing

NASA Technical Reports Server (NTRS)

Morrison, R. A.

1972-01-01

Ultrasonic waves were produced by striking the surface of a metal with the focused one-joule pulse of a Q-switched ruby laser. Rayleigh (surface) waves and longitudinal waves were detected with conventional transducers. Optical methods of detection were tested and developed. Rayleigh waves were produced with an oscillator and transducer. They were optically detected on curved polished surfaces, and on unpolished surfaces. The technique uses a knife edge to detect small angle changes of the surface as the wave pulse passes the illuminated spot. Optical flaw detection using pulse echo and attenuation is demonstrated.

Fabrication and characterization of SU-8-based capacitive micromachined ultrasonic transducer for airborne applications

NASA Astrophysics Data System (ADS)

Joseph, Jose; Singh, Shiv Govind; Vanjari, Siva Rama Krishna

2018-01-01

We present a successful fabrication and characterization of a capacitive micromachined ultrasonic transducer (CMUT) with SU-8 as the membrane material. The goal of this research is to develop a post-CMOS compatible CMUT that can be monolithically integrated with the CMOS circuitry. The fabrication is based on a simple, three mask process, with all wet etching steps involved so that the device can be realized with minimal laboratory conditions. The maximum temperature involved in the whole process flow was 140°C, and hence, it is post-CMOS compatible. The fabricated device exhibited a resonant frequency of 835 kHz with bandwidth 62 kHz, when characterized in air. The pull-in and snapback characteristics of the device were analyzed. The influence of membrane radius on the center frequency and bandwidth was also experimentally evaluated by fabricating CMUTs with membrane radius varying from 30 to 54 μm with an interval of 4 μm. These devices were vibrating at frequencies from 5.2 to 1.8 MHz with an average Q-factor of 23.41. Acoustic characterization of the fabricated devices was performed in air, demonstrating the applicability of SU-8 CMUTs in airborne applications.

Ultrasonic Real-Time Quality Monitoring Of Aluminum Spot Weld Process

NASA Astrophysics Data System (ADS)

Perez Regalado, Waldo Josue

The real-time ultrasonic spot weld monitoring system, introduced by our research group, has been designed for the unsupervised quality characterization of the spot welding process. It comprises the ultrasonic transducer (probe) built into one of the welding electrodes and an electronics hardware unit which gathers information from the transducer, performs real-time weld quality characterization and communicates with the robot programmable logic controller (PLC). The system has been fully developed for the inspection of spot welds manufactured in steel alloys, and has been mainly applied in the automotive industry. In recent years, a variety of materials have been introduced to the automotive industry. These include high strength steels, magnesium alloys, and aluminum alloys. Aluminum alloys have been of particular interest due to their high strength-to-weight ratio. Resistance spot welding requirements for aluminum vary greatly from those of steel. Additionally, the oxide film formed on the aluminum surface increases the heat generation between the copper electrodes and the aluminum plates leading to accelerated electrode deterioration. Preliminary studies showed that the real-time quality inspection system was not able to monitor spot welds manufactured with aluminum. The extensive experimental research, finite element modelling of the aluminum welding process and finite difference modeling of the acoustic wave propagation through the aluminum spot welds presented in this dissertation, revealed that the thermodynamics and hence the acoustic wave propagation through an aluminum and a steel spot weld differ significantly. For this reason, the hardware requirements and the algorithms developed to determine the welds quality from the ultrasonic data used on steel, no longer apply on aluminum spot welds. After updating the system and designing the required algorithms, parameters such as liquid nugget penetration and nugget diameter were available in the ultrasonic data acquired during the aluminum welding process. Finally, a fuzzy system was designed to receive these parameters and determine the weld quality.

Crossed SMPS MOSFET-based protection circuit for high frequency ultrasound transceivers and transducers

PubMed Central

2014-01-01

Background The ultrasonic transducer is one of the core components of ultrasound systems, and the transducer’s sensitivity is significantly related the loss of electronic components such as the transmitter, receiver, and protection circuit. In an ultrasonic device, protection circuits are commonly used to isolate the electrical noise between an ultrasound transmitter and transducer and to minimize unwanted discharged pulses in order to protect the ultrasound receiver. However, the performance of the protection circuit and transceiver obviously degrade as the operating frequency or voltage increases. We therefore developed a crossed SMPS (Switching Mode Power Supply) MOSFET-based protection circuit in order to maximize the sensitivity of high frequency transducers in ultrasound systems. The high frequency pulse signals need to trigger the transducer, and high frequency pulse signals must be received by the transducer. We therefore selected the SMPS MOSFET, which is the main component of the protection circuit, to minimize the loss in high frequency operation. The crossed configuration of the protection circuit can drive balanced bipolar high voltage signals from the pulser and transfer the balanced low voltage echo signals from the transducer. Methods The equivalent circuit models of the SMPS MOSFET-based protection circuit are shown in order to select the proper device components. The schematic diagram and operation mechanism of the protection circuit is provided to show how the protection circuit is constructed. The P-Spice circuit simulation was also performed in order to estimate the performance of the crossed MOSFET-based protection circuit. Results We compared the performance of our crossed SMPS MOSFET-based protection circuit with a commercial diode-based protection circuit. At 60 MHz, our expander and limiter circuits have lower insertion loss than the commercial diode-based circuits. The pulse-echo test is typical method to evaluate the sensitivity of ultrasonic transducers. Therefore, we performed a pulse-echo test using a single element transducer in order to utilize the crossed SMPS MOSFET-based protection circuit in an ultrasound system. Conclusions The SMPS-based protection circuit could be a viable alternative that provides better sensitivity, especially for high frequency ultrasound applications. PMID:24924595

Two transducer formula for more precise determination of ultrasonic phase velocity from standing wave measurements

NASA Technical Reports Server (NTRS)

Ringermacher, H. I.; Moerner, W. E.; Miller, J. G.

1974-01-01

A two transducer correction formula valid for both solid and liquid specimens is presented. Using computer simulations of velocity measurements, the accuracy and range of validity of the results are discussed and are compared with previous approximations.

Preparation and Characteristics of Ultrasonic Transducers for High Temperature Using PbNb2O6

NASA Astrophysics Data System (ADS)

Soejima, Junichiro; Sato, Kokichi; Nagata, Kunihiro

2000-05-01

The substance PZT(Pb(Zr, Ti)O3) is chiefly used for piezoceramic transducers in many ultrasonic flow meters. It is difficult to use PZT transducers for flow meters for automobile exhaust gas at high temperatures over 350°C. Lead niobate (PbNb2O6) has a high Curie temperature of 540°C and a low mechanical quality factor, and is the most suitable as the sensor element in flow meters for automobile exhaust gas. However, it is difficult to fabricate dense PbNb2O6 ceramics that have good piezoelectric properties. In this study, ceramics with high density and a high piezoelectric effect were fabricated by adding various elements such as Mn and Ca to PbNb2O6 and by examining the sintering process. A Langevin transducer with a resonance frequency of 80 kHz was made for measuring automobile exhaust gas flow using PbNb2O6 ceramics.

Structural health monitoring of glass/epoxy composite plates with MEMS PMN-PT sensors

NASA Astrophysics Data System (ADS)

Simon, Brenton R.; Tang, Hong-Yue; Horsley, David A.; La Saponara, Valeria; Lestari, Wahyu

2009-03-01

Sensors constructed with single-crystal PMN-PT, i.e. Pb(Mg1/3Nb2/3)O3-PbTiO3 or PMN, are developed in this paper for structural health monitoring of composite plates. To determine the potential of PMN-PT for this application, glass/epoxy composite specimens were created containing an embedded delamination-starter. Two different piezoelectric materials were bonded to the surface of each specimen: PMN-PT, the test material, was placed on one side of the specimen, while a traditional material, PZT-4, was placed on the other. A comparison of the ability of both materials to transmit and receive an ultrasonic pulse was conducted, with the received signal detected by both a second surface-bonded transducer constructed of the same material, as well as a laser Doppler vibrometer (LDV) analyzing the same location. The optimal frequency range of both sets of transducers is discussed and a comparison is presented of the experimental results to theory. The specimens will be fatigued until failure with further data collected every 3,000 cycles to characterize the ability of each material to detect the growing delamination in the composite structure. This additional information will be made available during the conference.

Micromachined ultrasound transducers with improved coupling factors from a CMOS compatible process

PubMed

Eccardt; Niederer

2000-03-01

For medical high frequency acoustic imaging purposes the reduction in size of a single transducer element for one-dimensional and even more for two-dimensional arrays is more and more limited by fabrication and cabling technology. In the fields of industrial distance measurement and simple object recognition low cost phased arrays are lacking. Both problems can be solved with micromachined ultrasound transducers (MUTs). A single transducer is made of a large number of microscopic elements. Because of the array structure of these transducers, groups of elements can be built up and used as a phased array. By integrating parts of the sensor electronics on chip, the cabling effort for arrays can be reduced markedly. In contrast to standard ultrasonic technology, which is based on massive thickness resonators, vibrating membranes are the radiating elements of the MUTs. New micromachining technologies have emerged, allowing a highly reproducible fabrication of electrostatically driven membranes with gap heights below 500 nm. A microelectronic BiCMOS process was extended for surface micromechanics (T. Scheiter et al., Proceedings 11th European Conference on Solid-State Transducers, Warsaw, Vol. 3, 1997, pp. 1595-1598). Additional process steps were included for the realization of the membranes which form sealed cavities with the underlying substrate. Membrane and substrate are the opposite electrodes of a capacitive transducer. The transducers can be integrated monolithically on one chip together with the driving, preamplifying and multiplexing circuitry, thus reducing parasitic capacities and noise level significantly. Owing to their low mass the transducers are very well matched to fluid loads, resulting in a very high bandwidth of 50-100% (C. Eccardt et al., Proceedings Ultrasonics Symposium, San Antonio, Vol. 2, 1996, pp. 959-962; P.C. Eccardt et al., Proceedings of the 1997 Ultrasonics Symposium, Toronto, Vol. 2, 1997, pp. 1609-1618). In the following it is shown how the BiCMOS process has been modified to meet the demands for ultrasound generation and reception. Bias and driving voltages have been reduced down to the 10 V range. The electromechanical coupling is now almost comparable with that for piezoelectric transducers. The measurements exhibit sound pressures and bandwidths that are at least comparable with those of conventional piezoelectric transducer arrays.

Lamb wave propagation in monocrystalline silicon wafers.

PubMed

Fromme, Paul; Pizzolato, Marco; Robyr, Jean-Luc; Masserey, Bernard

2018-01-01

Monocrystalline silicon wafers are widely used in the photovoltaic industry for solar panels with high conversion efficiency. Guided ultrasonic waves offer the potential to efficiently detect micro-cracks in the thin wafers. Previous studies of ultrasonic wave propagation in silicon focused on effects of material anisotropy on bulk ultrasonic waves, but the dependence of the wave propagation characteristics on the material anisotropy is not well understood for Lamb waves. The phase slowness and beam skewing of the two fundamental Lamb wave modes A 0 and S 0 were investigated. Experimental measurements using contact wedge transducer excitation and laser measurement were conducted. Good agreement was found between the theoretically calculated angular dependency of the phase slowness and measurements for different propagation directions relative to the crystal orientation. Significant wave skew and beam widening was observed experimentally due to the anisotropy, especially for the S 0 mode. Explicit finite element simulations were conducted to visualize and quantify the guided wave beam skew. Good agreement was found for the A 0 mode, but a systematic discrepancy was observed for the S 0 mode. These effects need to be considered for the non-destructive testing of wafers using guided waves.

Method for measuring liquid viscosity and ultrasonic viscometer

DOEpatents

Sheen, Shuh-Haw; Lawrence, William P.; Chien, Hual-Te; Raptis, Apostolos C.

1994-01-01

An ultrasonic viscometer and method for measuring fluid viscosity are provided. Ultrasonic shear and longitudinal waves are generated and coupled to the fluid. Reflections from the generated ultrasonic shear and longitudinal waves are detected. Phase velocity of the fluid is determined responsive to the detected ultrasonic longitudinal waves reflections. Viscosity of the fluid is determined responsive to the detected ultrasonic shear waves reflections. Unique features of the ultrasonic viscometer include the use of a two-interface fluid and air transducer wedge to measure relative signal change and to enable self calibration and the use of a ratio of reflection coefficients for two different frequencies to compensate for environmental changes, such as temperature.

Monitoring the integrity of massive aluminum structures using PZT transducers and the technique of impedance

NASA Astrophysics Data System (ADS)

da Costa, Rosalba; Maia, Joaquim M.; Assef, Amauri A.; Pichorim, Sergio F.; Costa, Eduardo T.; L. S. N. Button, Vera

2015-04-01

Safety, performance, economy and durability are essential items to qualify materials for the manufacturing of structures used in different areas. Generally, the materials used for this purpose are formed by composites and sometimes they can present failure during the manufacturing process. Such failures can also occur during use due to fatigue and wear, causing damage often difficult to be visually detected. In these cases, the use of non destructive testing (NDT) has proven to be a good choice for assessing the materials quality. The objective of this work was the electromechanical impedance evaluation of massive aluminum structures using ultrasonic transducers to detect discontinuities in the material. The tests have been done using an impedance analyzer (Agilent 4294A), an ultrasound transducer (1.6 MHz of central frequency), two types of PZT ceramics (0.267 mm and 1 mm thickness) and four aluminum samples (250 x 50 x 50 mm) with the transducer placed at three different regions. One sample was kept intact (reference) and the others were drilled in three positions with different sizes of holes (5 mm. 8 mm and 11 mm). The electromechanical impedance was recorded for each sample. The root mean square deviation index (RMSD) between the impedance magnitude of the reference and damaged samples was calculated and it was observed an increase in the RMSD due to the increase of the diameter of the holes (failures) in the samples completely drilled. The results show that the proposed methodology is suitable for monitoring the integrity of aluminum samples. The technique may be evaluated in characterizing other materials to be used in the construction of prostheses and orthoses.

Characterization of mechanical properties of leather with airborne ultrasonics

USDA-ARS?s Scientific Manuscript database

A nondestructive method to accurately evaluate the quality of hides and leather is urgently needed by leather and hide industries. We previously reported the research results for airborne ultrasonic (AU) testing using non-contact transducers to evaluate the quality of hides and leather. The abilit...

Application of neural networks to prediction of advanced composite structures mechanical response and behavior

NASA Technical Reports Server (NTRS)

Cios, K. J.; Vary, A.; Berke, L.; Kautz, H. E.

1992-01-01

Two types of neural networks were used to evaluate acousto-ultrasonic (AU) data for material characterization and mechanical reponse prediction. The neural networks included a simple feedforward network (backpropagation) and a radial basis functions network. Comparisons of results in terms of accuracy and training time are given. Acousto-ultrasonic (AU) measurements were performed on a series of tensile specimens composed of eight laminated layers of continuous, SiC fiber reinforced Ti-15-3 matrix. The frequency spectrum was dominated by frequencies of longitudinal wave resonance through the thickness of the specimen at the sending transducer. The magnitude of the frequency spectrum of the AU signal was used for calculating a stress-wave factor based on integrating the spectral distribution function and used for comparison with neural networks results.

Method and apparatus to assess compartment syndrome

NASA Technical Reports Server (NTRS)

Hargens, Alan R. (Inventor); Yost, William T. (Inventor); Ueno, Toshiaki (Inventor)

2008-01-01

A method and apparatus for measuring pressure buildup in a body compartment that encases muscular tissue. The method includes assessing the body compartment configuration and identifying the effect of pulsatile components on at least one compartment dimension. This process is used in preventing tissue necrosis, and in decisions of whether to perform surgery on the body compartment for prevention of Compartment Syndrome. An apparatus is used for measuring excess pressure in the body compartment having components for imparting ultrasonic waves such as a transducer, placing the transducer to impart the ultrasonic waves, capturing the reflected imparted ultrasonic waves, and converting them to electrical signals, a pulsed phase-locked loop device for assessing a body compartment configuration and producing an output signal, and means for mathematically manipulating the output signal to thereby categorize pressure build-up in the body compartment from the mathematical manipulations.

Application of Discrete Huygens Method for Diffraction of Transient Ultrasonic Field

NASA Astrophysics Data System (ADS)

Alia, A.

2018-01-01

Several time-domain methods have been widely used to predict impulse response in acoustics. Despite its great potential, Discrete Huygens Method (DHM) has not been as widely used in the domain of ultrasonic diffraction as in other fields. In fact, little can be found in literature about the application of the DHM to diffraction phenomenon that can be described in terms of direct and edge waves, a concept suggested by Young since 1802. In this paper, a simple axisymmetric DHM-model has been used to simulate the transient ultrasonic field radiation of a baffled transducer and its diffraction by a target located on axis. The results are validated by impulse response based calculations. They indicate the capability of DHM to simulate diffraction occurring at transducer and target edges and to predict the complicated transient field in pulse mode.

Concrete Infill Monitoring in Concrete-Filled FRP Tubes Using a PZT-Based Ultrasonic Time-of-Flight Method.

PubMed

Luo, Mingzhang; Li, Weijie; Hei, Chuang; Song, Gangbing

2016-12-07

Concrete-filled fiber-reinforced polymer tubes (CFFTs) have attracted interest for their structural applications in corrosive environments. However, a weak interfacial strength between the fiber-reinforced polymer (FRP) tube and the concrete infill may develop due to concrete shrinkage and inadequate concrete compaction during concrete casting, which will destroy the confinement effect and thereby reduce the load bearing capacity of a CFFT. In this paper, the lead zirconate titanate (PZT)-based ultrasonic time-of-flight (TOF) method was adopted to assess the concrete infill condition of CFFTs. The basic idea of this method is that the velocity of the ultrasonic wave propagation in the FRP material is about half of that in concrete material. Any voids or debonding created along the interface between the FRP tube and the concrete will delay the arrival time between the pairs of PZT transducers. A comparison of the arrival times of the PZT pairs between the intact and the defected CFFT was made to assess the severity of the voids or the debonding. The feasibility of the methodology was analyzed using a finite-difference time-domain-based numerical simulation. Experiments were setup to validate the numerical results, which showed good agreement with the numerical findings. The results showed that the ultrasonic time-of-flight method is able to detect the concrete infill condition of CFFTs.

Concrete Infill Monitoring in Concrete-Filled FRP Tubes Using a PZT-Based Ultrasonic Time-of-Flight Method

PubMed Central

Luo, Mingzhang; Li, Weijie; Hei, Chuang; Song, Gangbing

2016-01-01

Concrete-filled fiber-reinforced polymer tubes (CFFTs) have attracted interest for their structural applications in corrosive environments. However, a weak interfacial strength between the fiber-reinforced polymer (FRP) tube and the concrete infill may develop due to concrete shrinkage and inadequate concrete compaction during concrete casting, which will destroy the confinement effect and thereby reduce the load bearing capacity of a CFFT. In this paper, the lead zirconate titanate (PZT)-based ultrasonic time-of-flight (TOF) method was adopted to assess the concrete infill condition of CFFTs. The basic idea of this method is that the velocity of the ultrasonic wave propagation in the FRP material is about half of that in concrete material. Any voids or debonding created along the interface between the FRP tube and the concrete will delay the arrival time between the pairs of PZT transducers. A comparison of the arrival times of the PZT pairs between the intact and the defected CFFT was made to assess the severity of the voids or the debonding. The feasibility of the methodology was analyzed using a finite-difference time-domain-based numerical simulation. Experiments were setup to validate the numerical results, which showed good agreement with the numerical findings. The results showed that the ultrasonic time-of-flight method is able to detect the concrete infill condition of CFFTs. PMID:27941617

Development of coaxial ultrasonic probe for fatty liver diagnostic system using ultrasonic velocity change

NASA Astrophysics Data System (ADS)

Hori, Makoto; Yokota, Daiki; Aotani, Yuhei; Kumagai, Yuta; Wada, Kenji; Matsunaka, Toshiyuki; Morikawa, Hiroyasu; Horinaka, Hiromichi

2017-07-01

A diagnostic system for fatty liver at an early stage is needed because fatty liver is linked to metabolic syndrome. We have already proposed a fatty liver diagnosis method based on the temperature coefficient of ultrasonic velocity. In this study, we fabricated a coaxial ultrasonic probe by integrating two kinds of transducers for warming and signal detection. The diagnosis system equipped with the coaxial probe was applied to tissue-mimicking phantoms including the fat area. The fat content rates corresponding to the set rates of the phantoms were estimated by the ultrasonic velocity-change method.

Anodic bonding using SOI wafer for fabrication of capacitive micromachined ultrasonic transducers

NASA Astrophysics Data System (ADS)

Bellaredj, M.; Bourbon, G.; Walter, V.; Le Moal, P.; Berthillier, M.

2014-02-01

In medical ultrasound imaging, mostly piezoelectric crystals are used as ultrasonic transducers. Capacitive micromachined ultrasonic transducers (CMUTs) introduced around 1994 have been shown to be a good alternative to conventional piezoelectric transducers in various aspects, such as sensitivity, transduction efficiency or bandwidth. This paper focuses on a fabrication process for CMUTs using anodic bonding of a silicon on insulator wafer on a glass wafer. The processing steps are described leading to a good control of the mechanical response of the membrane. This technology makes possible the fabrication of large membranes and can extend the frequency range of CMUTs to lower frequencies of operation. Silicon membranes having radii of 50, 70, 100 and 150 µm and a 1.5 µm thickness are fabricated and electromechanically characterized using an auto-balanced bridge impedance analyzer. Resonant frequencies from 0.6 to 2.3 MHz and an electromechanical coupling coefficient around 55% are reported. The effects of residual stress in the membranes and uncontrolled clamping conditions are clearly responsible for the discrepancies between experimental and theoretical values of the first resonance frequency. The residual stress in the membranes is determined to be between 90 and 110 MPa. The actual boundary conditions are between the clamped condition and the simply supported condition and can be modeled with a torsional stiffness of 2.10-7 Nm rad-1 in the numerical model.

New real-time algorithms for arbitrary, high precision function generation with applications to acoustic transducer excitation

NASA Astrophysics Data System (ADS)

Gaydecki, P.

2009-07-01

A system is described for the design, downloading and execution of arbitrary functions, intended for use with acoustic and low-frequency ultrasonic transducers in condition monitoring and materials testing applications. The instrumentation comprises a software design tool and a powerful real-time digital signal processor unit, operating at 580 million multiplication-accumulations per second (MMACs). The embedded firmware employs both an established look-up table approach and a new function interpolation technique to generate the real-time signals with very high precision and flexibility. Using total harmonic distortion (THD) analysis, the purity of the waveforms have been compared with those generated using traditional analogue function generators; this analysis has confirmed that the new instrument has a consistently superior signal-to-noise ratio.

A top-crossover-to-bottom addressed segmented annular array using piezoelectric micromachined ultrasonic transducers

NASA Astrophysics Data System (ADS)

Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Hong, Hyeryung; Yuen Song, Hi; Oh, Inn-yeal; Park, Chul Soon; Choi, Hongsoo

2015-11-01

We design and fabricate segmented annular arrays (SAAs) using piezoelectric micromachined ultrasonic transducers (pMUTs) to demonstrate the feasibility of acoustic focusing of ultrasound. The fabricated SAAs have 25 concentric top-electrode signal lines and eight bottom-electrodes for grounding to enable electronic steering of selectively grouped ultrasonic transducers from 2393 pMUT elements. Each element in the array is connected by top-crossover-to-bottom metal bridges, which reduce the parasitic capacitance. Circular-shaped pMUT elements, 120 μm in diameter, are fabricated using 1 μm-thick sol-gel lead zirconate titanate on a silicon wafer. To utilize the high-density pMUT array, a deep reactive ion etching process is used for anisotropic silicon etching to realize the transducer membranes. The resonant frequency and effective coupling coefficient of the elements, measured with an impedance analyzer, yields 1.517 MHz and 1.29%, respectively, in air. The SAAs using pMUTs are packaged on a printed circuit board and coated with parylene C for acoustic intensity measurements in water. The ultrasound generated by each segmented array is focused on a selected point in space. When a 5 Vpp, 1.5 MHz square wave is applied, the maximum spatial peak temporal average intensity ({{I}\\text{spta}} ) is found to be 79 mW cm-2 5 mm from the SAAs’ surface without beamforming. The beam widths (-3 dB) of ultrasonic radiation patterns in the elevation and azimuth directions are recorded as 3 and 3.4 mm, respectively. The results successfully show the feasibility of focusing ultrasound on a small area with SAAs using pMUTs.

Quantitative ultrasonic testing of acoustically anisotropic materials with verification on austenitic and dissimilar weld joints

NASA Astrophysics Data System (ADS)

Boller, C.; Pudovikov, S.; Bulavinov, A.

2012-05-01

Austenitic stainless steel materials are widely used in a variety of industry sectors. In particular, the material is qualified to meet the design criteria of high quality in safety related applications. For example, the primary loop of the most of the nuclear power plants in the world, due to high durability and corrosion resistance, is made of this material. Certain operating conditions may cause a range of changes in the integrity of the component, and therefore require nondestructive testing at reasonable intervals. These in-service inspections are often performed using ultrasonic techniques, in particular when cracking is of specific concern. However, the coarse, dendritic grain structure of the weld material, formed during the welding process, is extreme and unpredictably anisotropic. Such structure is no longer direction-independent to the ultrasonic wave propagation; therefore, the ultrasonic beam deflects and redirects and the wave front becomes distorted. Thus, the use of conventional ultrasonic testing techniques using fixed beam angles is very limited and the application of ultrasonic Phased Array techniques becomes desirable. The "Sampling Phased Array" technique, invented and developed by Fraunhofer IZFP, allows the acquisition of time signals (A-scans) for each individual transducer element of the array along with fast image reconstruction techniques based on synthetic focusing algorithms. The reconstruction considers the sound propagation from each image pixel to the individual sensor element. For anisotropic media, where the sound beam is deflected and the sound path is not known a-priori, a novel phase adjustment technique called "Reverse Phase Matching" is implemented. By taking into account the anisotropy and inhomogeneity of the weld structure, a ray tracing algorithm for modeling the acoustic wave propagation and calculating the sound propagation time is applied. This technique can be utilized for 2D and 3D real time image reconstruction. The "Gradient Constant Descent Method" (GECDM), an iterative algorithm, is implemented, which is essential for examination of inhomogeneous anisotropic media having unknown properties (elastic constants). The Sampling Phased Array technique with Reverse Phase Matching extended by GECDM-technique determines unknown elastic constants and provides reliable and efficient quantitative flaw detection in the austenitic welds. The validation of ray-tracing algorithm and GECDM-method is performed by number of experiments on test specimens with artificial as well as natural material flaws. A mechanized system for ultrasonic testing of stainless steel and dissimilar welds is developed. The system works on both conventional and Sampling Phased Array techniques. The new frontend ultrasonic unit with optical data link allows the 3D visualization of the inspection results in real time.

Influence of acoustic impedance of multilayer acoustic systems on the transfer function of ultrasonic airborne transducers.

PubMed

Gudra, Tadeusz; Opieliński, Krzysztof J

2002-05-01

In different solutions of ultrasonic transducers radiating acoustic energy into the air there occurs the problem of the proper selection of the acoustic impedance of one or more matching layers. The goal of this work was a computer analysis of the influence of acoustic impedance on the transfer function of piezoceramic transducers equipped with matching layers. Cases of resonance and non-resonance matching impedance in relation to the transfer function and the energy transmission coefficient for solid state-air systems were analysed. With stable thickness of matching layers the required shape of the transfer function can be obtained through proper choice of acoustic impedance were built (e.g. maximal flat function). The proper choice of acoustic impedance requires an elaboration of precise methods of synthesis of matching systems. Using the known matching criteria (Chebyshev's, DeSilets', Souquet's), the transfer function characteristics of transducers equipped with one, two, and three matching layers as well as the optimisation methods of the energy transmission coefficient were presented. The influence of the backside load of the transducer on the shape of transfer function was also analysed. The calculation results of this function for different loads of the transducer backside without and with the different matching layers were presented. The proper load selection allows us to obtain the desired shape of the transfer function, which determines the pulse shape generated by the transducer.

Method and apparatus for air-coupled transducer

NASA Technical Reports Server (NTRS)

Song, Junho (Inventor); Chimenti, Dale E. (Inventor)

2010-01-01

An air-coupled transducer includes a ultrasonic transducer body having a radiation end with a backing fixture at the radiation end. There is a flexible backplate conformingly fit to the backing fixture and a thin membrane (preferably a metallized polymer) conformingly fit to the flexible backplate. In one embodiment, the backing fixture is spherically curved and the flexible backplate is spherically curved. The flexible backplate is preferably patterned with pits or depressions.

Portable rapid and quiet drill

NASA Technical Reports Server (NTRS)

Badescu, Mireca (Inventor); Chang, Zenshea (Inventor); Sherrit, Stewart (Inventor); Bar-Cohen, Yoseph (Inventor); Bao, Xiaoqi (Inventor)

2010-01-01

A hand-held drilling device, and method for drilling using the device, has a housing, a transducer within the housing, with the transducer effectively operating at ultrasonic frequencies, a rotating motor component within the housing and rigid cutting end-effector rotationally connected to the rotating motor component and vibrationally connected to the transducer. The hand-held drilling device of the present invention operates at a noise level of from about 50 decibels or less.

Development of glucose measurement system based on pulsed laser-induced ultrasonic method

NASA Astrophysics Data System (ADS)

Ren, Zhong; Wan, Bin; Liu, Guodong; Xiong, Zhihua

2016-09-01

In this study, a kind of glucose measurement system based on pulsed-induced ultrasonic technique was established. In this system, the lateral detection mode was used, the Nd: YAG pumped optical parametric oscillator (OPO) pulsed laser was used as the excitation source, the high sensitivity ultrasonic transducer was used as the signal detector to capture the photoacoustic signals of the glucose. In the experiments, the real-time photoacoustic signals of glucose aqueous solutions with different concentrations were captured by ultrasonic transducer and digital oscilloscope. Moreover, the photoacoustic peak-to-peak values were gotten in the wavelength range from 1300nm to 2300nm. The characteristic absorption wavelengths of glucose were determined via the difference spectral method and second derivative method. In addition, the prediction models of predicting glucose concentrations were established via the multivariable linear regression algorithm and the optimal prediction model of corresponding optimal wavelengths. Results showed that the performance of the glucose system based on the pulsed-induced ultrasonic detection method was feasible. Therefore, the measurement scheme and prediction model have some potential value in the fields of non-invasive monitoring the concentration of the glucose gradient, especially in the food safety and biomedical fields.

Comparison of a piezoceramic transducer and an EMAT for the omnidirectional transduction of SH0

NASA Astrophysics Data System (ADS)

Gauthier, Baptiste; Thon, Aurelien; Belanger, Pierre

2018-04-01

The fundamental shear horizontal ultrasonic guided wave mode has unique properties for non-destructive testing as well as structural health monitoring applications. It is the only non-dispersive guided wave mode and it is not attenuated by fluid loading. Moreover, shear horizontal waves do not convert to other guided wave modes when interacting with a boundary or defect parallel to the direction of polarization. In many applications, omnidirectional transduction is preferred so as to maximize the inspection coverage. The omnidirectional transduction of the fundamental shear horizontal ultrasonic guided wave mode is, however, challenging because a torsional surface stress is required. This paper compares the performances of two concepts recently proposed in the literature: 1- a piezoceramic transducer and 2- an electromagnetic-acoustic transducer. The piezoceramic transducer uses 6 trapezoidal shear piezoelectric elements arranged on a discretized circle. The electromagnetic acoustic transducer concept consists of a pair of ring-type permanent magnets and a coil wrapped in the radial direction. In this paper, both transducers were designed to have a 150 kHz centre frequency. Experimental results were performed on a thin aluminum plate using both transducers. A 3D laser Doppler vibrometer was used to verify the omnidirectional nature, the mode selectivity and the frequency response of the transducers. The EMAT has undeniable advantages in terms of omnidirectionality and mode selectivity. However it has a larger footprint than the piezoceramic concept and is only suitable for the inspection of metallic structures.

2D Analytical Model for the Directivity Prediction of Ultrasonic Contact Type Transducers in the Generation of Guided Waves.

PubMed

Tiwari, Kumar Anubhav; Raisutis, Renaldas; Mazeika, Liudas; Samaitis, Vykintas

2018-03-26

In this paper, a novel 2D analytical model based on the Huygens's principle of wave propagation is proposed in order to predict the directivity patterns of contact type ultrasonic transducers in the generation of guided waves (GWs). The developed model is able to estimate the directivity patterns at any distance, at any excitation frequency and for any configuration and shape of the transducers with prior information of phase dispersive characteristics of the guided wave modes and the behavior of transducer. This, in turn, facilitates to choose the appropriate transducer or arrays of transducers, suitable guided wave modes and excitation frequency for the nondestructive testing (NDT) and structural health monitoring (SHM) applications. The model is demonstrated for P1-type macro-fiber composite (MFC) transducer glued on a 2 mm thick aluminum (Al) alloy plate. The directivity patterns of MFC transducer in the generation of fundamental guided Lamb modes (the S0 and A0) and shear horizontal mode (the SH0) are successfully obtained at 80 kHz, 5-period excitation signal. The results are verified using 3D finite element (FE) modelling and experimental investigation. The results obtained using the proposed model shows the good agreement with those obtained using numerical simulations and experimental analysis. The calculation time using the analytical model was significantly shorter as compared to the time spent in experimental analysis and FE numerical modelling.

A spherically-shaped PZT thin film ultrasonic transducer with an acoustic impedance gradient matching layer based on a micromachined periodically structured flexible substrate.

PubMed

Feng, Guo-Hua; Liu, Wei-Fan

2013-10-09

This paper presents the microfabrication of an acoustic impedance gradient matching layer on a spherically-shaped piezoelectric ultrasonic transducer. The acoustic matching layer can be designed to achieve higher acoustic energy transmission and operating bandwidth. Also included in this paper are a theoretical analysis of the device design and a micromachining technique to produce the novel transducer. Based on a design of a lead titanium zirconium (PZT) micropillar array, the constructed gradient acoustic matching layer has much better acoustic transmission efficiency within a 20-50 MHz operation range compared to a matching layer with a conventional quarter-wavelength thickness Parylene deposition. To construct the transducer, periodic microcavities are built on a flexible copper sheet, and then the sheet forms a designed curvature with a ball shaping. After PZT slurry deposition, the constructed PZT micropillar array is released onto a curved thin PZT layer. Following Parylene conformal coating on the processed PZT micropillars, the PZT micropillars and the surrounding Parylene comprise a matching layer with gradient acoustic impedance. By using the proposed technique, the fabricated transducer achieves a center frequency of 26 MHz and a -6 dB bandwidth of approximately 65%.

Ultrasonic correlator versus signal averager as a signal to noise enhancement instrument

NASA Technical Reports Server (NTRS)

Kishoni, Doron; Pietsch, Benjamin E.

1989-01-01

Ultrasonic inspection of thick and attenuating materials is hampered by the reduced amplitudes of the propagated waves to a degree that the noise is too high to enable meaningful interpretation of the data. In order to overcome the low Signal to Noise (S/N) ratio, a correlation technique has been developed. In this method, a continuous pseudo-random pattern generated digitally is transmitted and detected by piezoelectric transducers. A correlation is performed in the instrument between the received signal and a variable delayed image of the transmitted one. The result is shown to be proportional to the impulse response of the investigated material, analogous to a signal received from a pulsed system, with an improved S/N ratio. The degree of S/N enhancement depends on the sweep rate. This paper describes the correlator, and compares it to the method of enhancing S/N ratio by averaging the signals. The similarities and differences between the two are highlighted and the potential advantage of the correlator system is explained.

Ultrasonic correlator versus signal averager as a signal to noise enhancement instrument

NASA Technical Reports Server (NTRS)

Kishoni, Doron; Pietsch, Benjamin E.

1990-01-01

Ultrasonic inspection of thick and attenuating materials is hampered by the reduce amplitudes of the propagated waves to a degree that the noise is too high to enable meaningful interpretation of the data. In order to overcome the low signal to noise ratio (S/N), a correlation technique has been developed. In this method, a continuous pseudo-random pattern generated digitally is transmitted and detected by piezoelectric transducers. A correlation is performed in the instrument between the received signal and a variable delayed image of the transmitted one. The result is shown to be proportional to the impulse response of the investigated material, analogous to a signal received from a pulsed system, with an improved S/N ratio. The degree of S/N enhancement depends on the sweep rate. The correlator is described, and it is compared to the method of enhancing S/N ratio by averaging the signals. The similarities and differences between the two are highlighted and the potential advantage of the correlator system is explained.

Effects of specimen resonances on acoustic-ultrasonic testing

NASA Technical Reports Server (NTRS)

Williams, J. H., Jr.; Kahn, E. B.; Lee, S. S.

1983-01-01

The effects of specimen resonances on acoustic ultrasonic (AU) nondestructive testing were investigated. Selected resonant frequencies and the corresponding normal mode nodal patterns of the aluminum block are measured up to 75.64 kHz. Prominent peaks in the pencil lead fracture and sphere impact spectra from the two transducer locations corresponded exactly to resonant frequencies of the block. It is established that the resonant frequencies of the block dominated the spectral content of the output signal. The spectral content of the output signals is further influenced by the transducer location relative to the resonant frequency nodal lines. Implications of the results are discussed in relation to AU parameters and measurements.

Methods And Apparatus For Acoustic Fiber Fractionation

DOEpatents

Brodeur, Pierre

1999-11-09

Methods and apparatus for acoustic fiber fractionation using a plane ultrasonic wave field interacting with water suspended fibers circulating in a channel flow using acoustic radiation forces to separate fibers into two or more fractions based on fiber radius, with applications of the separation concept in the pulp and paper industry. The continuous process relies on the use of a wall-mounted, rectangular cross-section piezoelectric ceramic transducer to selectively deflect flowing fibers as they penetrate the ultrasonic field. The described embodiment uses a transducer frequency of approximately 150 kHz. Depending upon the amount of dissolved gas in water, separation is obtained using a standing or a traveling wave field.

Radiation tolerance of piezoelectric bulk single-crystal aluminum nitride

DOE Office of Scientific and Technical Information (OSTI.GOV)

David A. Parks; Bernhard R. Tittmann

2014-07-01

For practical use in harsh radiation environments, we pose selection criteria for piezoelectric materials for nondestructive evaluation (NDE) and material characterization. Using these criteria, piezoelectric aluminum nitride is shown to be an excellent candidate. The results of tests on an aluminumnitride-based transducer operating in a nuclear reactor are also presented. We demonstrate the tolerance of single-crystal piezoelectric aluminum nitride after fast and thermal neutron fluences of 1.85 × 1018 neutron/cm2 and 5.8 × 1018 neutron/cm2, respectively, and a gamma dose of 26.8 MGy. The radiation hardness of AlN is most evident from the unaltered piezoelectric coefficient d33, which measured 5.5more » pC/N after a fast and thermal neutron exposure in a nuclear reactor core for over 120 MWh, in agreement with the published literature value. The results offer potential for improving reactor safety and furthering the understanding of radiation effects on materials by enabling structural health monitoring and NDE in spite of the high levels of radiation and high temperatures, which are known to destroy typical commercial ultrasonic transducers.« less

Polarization-dependent optical reflection ultrasonic detection

NASA Astrophysics Data System (ADS)

Zhu, Xiaoyi; Huang, Zhiyu; Wang, Guohe; Li, Wenzhao; Li, Changhui

2017-03-01

Although ultrasound transducers based on commercial piezoelectric-material have been widely used, they generally have limited bandwidth centered at the resonant frequency. Currently, several pure-optical ultrasonic detection methods have gained increasing interest due to their wide bandwidth and high sensitivity. However, most of them require customized components (such as micro-ring, SPR, Fabry-Perot film, etc), which limit their broad implementations. In this study, we presented a simple pure-optical ultrasound detection method, called "Polarization-dependent Reflection Ultrasonic Detection" (PRUD). It detects the intensity difference between two polarization components of the probe beam that is modulated by ultrasound waves. PRUD detect the two components by using a balanced detector, which effectively suppressed much of the unwanted noise. We have achieved the sensitivity (noise equivalent pressure) to be 1.7kPa, and this can be further improved. In addition, like many other pure-optical ultrasonic detection methods, PRUD also has a flat and broad bandwidth from almost zero to over 100MHz. Besides theoretical analysis, we did a phantom study by imaging a tungsten filament to demonstrate the performance of PRUD. We believe this simple and economic method will attract both researchers and engineers in optical and ultrasound fields.

Setting behaviour of luting cements monitored by an ultrasonic method.

PubMed

Tsubota, Keishi; Mori, Kentarou; Yasuda, Genta; Kawamoto, Ryo; Yoshida, Takeshi; Yamaguchi, Kanako; Kurokawa, Hiroyasu; Miyazaki, Masashi

2008-06-01

The purpose of this study was to monitor the setting behaviour and elastic modulus of luting cements using an ultrasonic device. The ultrasonic equipment comprised a pulser-receiver, transducers and an oscilloscope. The transit time through the cement disk was multiplied by the thickness of the specimen, and the sonic velocity within the material was then calculated. The sonic velocities of the longitudinal and shear waves were used to determine the elastic modulus. Analysis of variance and the Tukey HSD test were used to compare the elastic moduli of the set cements. In the earliest stages of the setting process, most of the ultrasound energy was absorbed by the cements and the sound waves were relatively weak. As the cements hardened, the sound velocities increased and this tendency differed among the luting cements used. The mean elastic moduli of the specimens ranged from 2.9 to 9.9 GPa after 15 min, from 14.4 to 20.3 GPa after 24 h and from 12.1 to 15.9 GPa after 1 month. The setting processes of the luting cements were thus clearly defined by using the present ultrasonic method.

Ultrasonic characterization of single drops of liquids

DOEpatents

Sinha, Dipen N.

1998-01-01

Ultrasonic characterization of single drops of liquids. The present invention includes the use of two closely spaced transducers, or one transducer and a closely spaced reflector plate, to form an interferometer suitable for ultrasonic characterization of droplet-size and smaller samples without the need for a container. The droplet is held between the interferometer elements, whose distance apart may be adjusted, by surface tension. The surfaces of the interferometer elements may be readily cleansed by a stream of solvent followed by purified air when it is desired to change samples. A single drop of liquid is sufficient for high-quality measurement. Examples of samples which may be investigated using the apparatus and method of the present invention include biological specimens (tear drops; blood and other body fluid samples; samples from tumors, tissues, and organs; secretions from tissues and organs; snake and bee venom, etc.) for diagnostic evaluation, samples in forensic investigations, and detection of drugs in small quantities.

Nonlinear ultrasonic fatigue crack detection using a single piezoelectric transducer

NASA Astrophysics Data System (ADS)

An, Yun-Kyu; Lee, Dong Jun

2016-04-01

This paper proposes a new nonlinear ultrasonic technique for fatigue crack detection using a single piezoelectric transducer (PZT). The proposed technique identifies a fatigue crack using linear (α) and nonlinear (β) parameters obtained from only a single PZT mounted on a target structure. Based on the different physical characteristics of α and β, a fatigue crack-induced feature is able to be effectively isolated from the inherent nonlinearity of a target structure and data acquisition system. The proposed technique requires much simpler test setup and less processing costs than the existing nonlinear ultrasonic techniques, but fast and powerful. To validate the proposed technique, a real fatigue crack is created in an aluminum plate, and then false positive and negative tests are carried out under varying temperature conditions. The experimental results reveal that the fatigue crack is successfully detected, and no positive false alarm is indicated.

Non-contact defect diagnostics in Cz-Si wafers using resonance ultrasonic vibrations

NASA Astrophysics Data System (ADS)

Belyaev, A.; Kochelap, V. A.; Tarasov, I.; Ostapenko, S.

2001-01-01

A new resonance effect of generation of sub-harmonic acoustic vibrations was applied to characterize defects in as-grown and processed Cz-Si wafers. Ultrasonic vibrations were generated into standard 8″ wafers using an external ultrasonic transducer and their amplitude recorded in a non-contact mode using a scanning acoustic probe. By tuning the frequency, f, of the transducer we observed generation of intense sub-harmonic acoustic mode ("whistle" or w-mode) with f/2 frequency. The characteristics of the w-mode-amplitude dependence, frequency scans, spatial distribution allow a clear distinction versus harmonic vibrations of the same wafer. The origin of sub-harmonic vibrations observed on 8″ Cz-Si wafers is attributed to a parametric resonance of flexural vibrations in thin silicon circular plates. We present evidence that "whistle" effect shows a strong dependence on the wafer's growth and processing history and can be used for quality assurance purposes.

Digital ultrasonics signal processing: Flaw data post processing use and description

NASA Technical Reports Server (NTRS)

Buel, V. E.

1981-01-01

A modular system composed of two sets of tasks which interprets the flaw data and allows compensation of the data due to transducer characteristics is described. The hardware configuration consists of two main units. A DEC LSI-11 processor running under the RT-11 sngle job, version 2C-02 operating system, controls the scanner hardware and the ultrasonic unit. A DEC PDP-11/45 processor also running under the RT-11, version 2C-02, operating system, stores, processes and displays the flaw data. The software developed the Ultrasonics Evaluation System, is divided into two catagories; transducer characterization and flaw classification. Each category is divided further into two functional tasks: a data acquisition and a postprocessor ask. The flaw characterization collects data, compresses its, and writes it to a disk file. The data is then processed by the flaw classification postprocessing task. The use and operation of a flaw data postprocessor is described.

Feasibility of MR-Temperature Mapping of Ultrasonic Heating from a CMUT

PubMed Central

Wong, Serena H.; Watkins, Ronald D.; Kupnik, Mario; Butts-Pauly, Kim; Khuri-Yakub, Butrus T.

2014-01-01

In the last decade, high intensity focused ultrasound (HIFU) has gained popularity as a minimally-invasive and non-invasive therapeutic tool for treatment of cancers, arrhythmias, and other medical conditions. HIFU therapy is often guided by magnetic resonance imaging (MRI), which provides anatomical images for therapeutic device placement, temperature maps for treatment guidance, and post-operative evaluation of the region of interest. While piezoelectric transducers are dominantly used for MR-guided HIFU, capacitive micromachined ultrasonic transducers (CMUTs) show competitive advantages such as ease of fabrication, integration with electronics, improved efficiency, and reduction of self-heating. In this paper, we will show our first results of an unfocused CMUT transducer monitored by MR-temperature maps. This 2.51 mm by 2.32 mm, unfocused CMUT heated a HIFU phantom by 14°C in 2.5 min. This temperature rise was successfully monitored by MR thermometry in a 3.0 T General Electric scanner. PMID:18467225

Apparatus for and Method of Monitoring Condensed Water in Steam Pipes at High Temperature

NASA Technical Reports Server (NTRS)

Lih, Shyh-Shiuh (Inventor); Bao, Xiaoqi (Inventor); Bar-Cohen, Yoseph (Inventor); Lee, Hyeong Jae (Inventor)

2016-01-01

A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

In-Service Monitoring of Steam Pipe Systems at High Temperatures

NASA Technical Reports Server (NTRS)

Sherrit, Stewart (Inventor); Scott, James Samson (Inventor); Bar-Cohen, Yoseph (Inventor); Badescu, Mircea (Inventor); Widholm, Scott E. (Inventor); Lih, Shyh-Shiuh (Inventor); Bao, Xiaoqi (Inventor); Blosiu, Julian O. (Inventor)

2014-01-01

A system and method for monitoring the properties of a fluid, such as water, in a steam pipe without mechanically penetrating the wall of the pipe. The system uses a piezoelectric transducer to launch an ultrasonic probe signal into the pipe. Reflected ultrasonic signals are captured in a transducer, which can be the same transducer that launched the probe signal. The reflected signals are subjected to data processing, which can include filtering, amplification, analog-to-digital conversion and autocorrelation analysis. A result is extracted which is indicative of a property of the fluid, such as a height of the condensed fluid, a cavitation of the condensed fluid, and a surface perturbation of the condensed fluid. The result can be recorded, displayed, and/or transmitted to another location. One embodiment of the system has been constructed and tested based on a general purpose programmable computer using instructions recorded in machine-readable non-volatile memory.

AlN-based piezoelectric micromachined ultrasonic transducer for photoacoustic imaging

NASA Astrophysics Data System (ADS)

Chen, Bingzhang; Chu, Futong; Liu, Xingzhao; Li, Yanrong; Rong, Jian; Jiang, Huabei

2013-07-01

We report on the fabrication of a piezoelectric micromachined ultrasonic transducer (pMUT) and its application to photoacoustic imaging. With c-axis orientation, AlN was grown on a 300 nm-thick SiO2 film and a 200 nm-thick bottom electrode at room temperature. The device consists of SiO2, bottom electrode, AlN films, upper electrode, and polyimide protective layer. An area ratio of 0.45 was used between the upper electrode and the vibration area of the pMUT to provide an optimal sensitivity of transducer. Its resonant frequency was measured to be 2.885 MHz, and the coupling coefficient in the range of 2.38%-3.71%. The fabricated pMUT was integrated with a photoacoustic imaging system and photoacoustic image of a phantom was obtained. The resolution of the system was measured to be about 240 μm.

Recent progress in online ultrasonic process monitoring

NASA Astrophysics Data System (ADS)

Wen, Szu-Sheng L.; Chen, Tzu-Fang; Ramos-Franca, Demartonne; Nguyen, Ky T.; Jen, Cheng-Kuei; Ihara, Ikuo; Derdouri, A.; Garcia-Rejon, Andres

1998-03-01

On-line ultrasonic monitoring of polymer co-extrusion and gas-assisted injection molding are presented. During the co- extrusion of high density polyethylene and Santoprene ultrasonic sensors consisting of piezoelectric transducers and clad ultrasonic buffer rods are used to detect the interface between these two polymers and the stability of the extrusion. The same ultrasonic sensor also measures the surface temperature of the extruded polymer. The results indicate that temperature measurements using ultrasound have a faster response time than those obtained by conventional thermocouple. In gas-assisted injection molding the polymer and gas flow front positions are monitored simultaneously. This information may be used to control the plunger movement.

Ultrasonic scanning for pallet part grading

Treesearch

Mohammed F. Kabir; Daniel L. Schmoldt; Mark E. Schafer; Philip A. Araman

2000-01-01

Sorting and grading of wooden pallet parts are key factors for pallet manufacturing quality and pallet durability. The feasibility of ultrasonic scanning for defect detection in pallet manufacturing is examined in this report. Scanning was conducted by two pressure-contact rolling transducers in a pitch-catch arrangement. Pallet part deckboards were fed through the...

Inorganic plugs removal using ultrasonic waves

NASA Astrophysics Data System (ADS)

Khan, Nasir; Pu, Chunsheng; Xu, Li; Lei, Zhang

2017-03-01

It is essential to recover the lost productivity caused by formation damage in the proximity of the wellbore during different well operations. In comparison to conventionally used methods, the efficiency, reliability, environment friendly, and simple and convenient technique of ultrasonic waves make it more attractive in petroleum industries. In current study, ultrasonic waves were applied to mitigate the formation damage caused by deposition of calcium carbonate (CaCO3) nearby well bore. Results showed that 100 minutes exposure time could efficiently recover 38.1% of original productivity but further increase in irradiation time (120mins) would decrease the recovery to 37.1%. This aberration can be attributed to the particle-bridge formation formed by larger particles at later stages and tendency of acoustic wave to push back the fluid flow. Moreover, ultrasonic waves transducer#2 (Frequency 20KHz and Power 1000W) could recovery maximum recovery of 36.3%, however, high frequency transducer was not effective in this recovery. This inorganic removal can be attributed to the cavitation and thermal energy produced through three different ways including cavitation, boundary friction and transformation upon hitting the medium.

Noncontact measurement of vibration using airborne ultrasound.

PubMed

Mater, O B; Remenieras, J P; Bruneel, C; Roncin, A; Patat, F

1998-01-01

A noncontact ultrasonic method for measuring the surface normal vibration of objects was studied. The instrument consists of a pair of 420 kHz ultrasonic air transducers. One is used to emit ultrasounds toward the moving surface, and the other receives the ultrasound reflected from the object under test. Two effects induce a phase modulation on the received signal. The first effect results from the variation of the round trip time interval tau required for the wavefront to go from the emitter to the moving surface and back to the receiver. This is the Doppler effect directly proportional to the surface displacement. The second effect results from the nonlinear parametric interactions of the ultrasonic beams (forward and backward) with the low frequency sound field emitted in the air by the vibrating surface. This latter phenomenon, which is a volume effect, is proportional to the velocity of the vibrating surface and increases with the distance between the transducers and the surface under test. The relative contribution of the Doppler and parametric effects are evaluated, and both have to be taken into account for ultrasonic interferometry in air.

In situ ice and structure thickness monitoring using integrated and flexible ultrasonic transducers

NASA Astrophysics Data System (ADS)

Liu, Q.; Wu, K.-T.; Kobayashi, M.; Jen, C.-K.; Mrad, N.

2008-08-01

Two types of ultrasonic sensors are presented for in situ capability development of ice detection and structure thickness measurement. These piezoelectric film based sensors have been fabricated by a sol-gel spray technique for aircraft environments and for temperatures ranging from -80 to 100 °C. In one sensor type, piezoelectric films of thickness greater than 40 µm are deposited directly onto the interior of a 1.3 mm thick aluminum (Al) alloy control surface (stabilizer) of an aircraft wing structure as integrated ultrasonic transducers (UTs). In the other sensor type, piezoelectric films are coated onto a 50 µm thick polyimide membrane as flexible UTs. These were subsequently glued onto similar locations at the same control surfaces. In situ monitoring of stabilizer outer skin thickness was performed. Ice build-up ranging from a fraction of 1 mm to less than 1.5 mm was also detected on a 3 mm thick Al plate. Measurements using these ultrasonic sensors agreed well with those obtained by a micrometer. Tradeoffs of these two approaches are presented.

Underwater detection by using ultrasonic sensor

NASA Astrophysics Data System (ADS)

Bakar, S. A. A.; Ong, N. R.; Aziz, M. H. A.; Alcain, J. B.; Haimi, W. M. W. N.; Sauli, Z.

2017-09-01

This paper described the low cost implementation of hardware and software in developing the system of ultrasonic which can visualize the feedback of sound in the form of measured distance through mobile phone and monitoring the frequency of detection by using real time graph of Java application. A single waterproof transducer of JSN-SR04T had been used to determine the distance of an object based on operation of the classic pulse echo detection method underwater. In this experiment, the system was tested by placing the housing which consisted of Arduino UNO, Bluetooth module of HC-06, ultrasonic sensor and LEDs at the top of the box and the transducer was immersed in the water. The system which had been tested for detection in vertical form was found to be capable of reporting through the use of colored LEDs as indicator to the relative proximity of object distance underwater form the sensor. As a conclusion, the system can detect the presence of an object underwater within the range of ultrasonic sensor and display the measured distance onto the mobile phone and the real time graph had been successfully generated.

Computerized Ultrasonic Testing System (CUTS) for in-process thickness determination

NASA Technical Reports Server (NTRS)

Frankel, J.; Doxbeck, M.; Schroeder, S. C.; Abbate, A.

1994-01-01

A Computerized Ultrasonic Testing System (CUTS) was developed to measure, in real-time, the rate of deposition and thickness of chromium plated on the inside of thick steel tubes. The measurements are made from the outside of the tubes with the ultrasonic pulse-echo technique. The resolution of the system is 2.5 micron. (0.0001 in.) and the accuracy is better than 10 micron (0.0004 in.). The thickness is measured using six transducers mounted at different locations on the tube. In addition, two transducers are mounted on two reference standards, thereby allowing the system to be continuously calibrated. The tube temperature varies during the process, thus the input from eight thermocouples, located at the measurement sites, is used to calculate and compensate for the change in return time of the ultrasonic echo due to the temperature dependence of the sound velocity. CUTS is applicable to any commercial process where real-time change of thickness of a sample has to be known, with the advantage of facilitating increased efficiency and of improving process control.

Mapping of cavitational activity in a pilot plant dyeing equipment.

PubMed

Actis Grande, G; Giansetti, M; Pezzin, A; Rovero, G; Sicardi, S

2015-11-01

A large number of papers of the literature quote dyeing intensification based on the application of ultrasound (US) in the dyeing liquor. Mass transfer mechanisms are described and quantified, nevertheless these experimental results in general refer to small laboratory apparatuses with a capacity of a few hundred millilitres and extremely high volumetric energy intensity. With the strategy of overcoming the scale-up inaccuracy consequent to the technological application of ultrasounds, a dyeing pilot-plant prototype of suitable liquor capacity (about 40 L) and properly simulating several liquor to textile hydraulic relationships was designed by including US transducers with different geometries. Optimal dyeing may be obtained by optimising the distance between transducer and textile material, the liquid height being a non-negligible operating parameter. Hence, mapping the cavitation energy in the machinery is expected to provide basic data on the intensity and distribution of the ultrasonic field in the aqueous liquor. A flat ultrasonic transducer (absorbed electrical power of 600 W), equipped with eight devices emitting at 25 kHz, was mounted horizontally at the equipment bottom. Considering industrial scale dyeing, liquor and textile substrate are reciprocally displaced to achieve a uniform colouration. In this technology a non uniform US field could affect the dyeing evenness to a large extent; hence, mapping the cavitation energy distribution in the machinery is expected to provide fundamental data and define optimal operating conditions. Local values of the cavitation intensity were recorded by using a carefully calibrated Ultrasonic Energy Meter, which is able to measure the power per unit surface generated by the cavitation implosion of bubbles. More than 200 measurements were recorded to define the map at each horizontal plane positioned at a different distance from the US transducer; tap water was heated at the same temperature used for dyeing tests (60°C). Different liquid flow rates were tested to investigate the effect of the hydrodynamics characterising the equipment. The mapping of the cavitation intensity in the pilot-plant machinery was performed to achieve with the following goals: (a) to evaluate the influence of turbulence on the cavitation intensity, and (b) to determine the optimal distance from the ultrasound device at which a fabric should be positioned, this parameter being a compromise between the cavitation intensity (higher next to the transducer) and the US field uniformity (achieved at some distance from this device). By carrying out dyeing tests of wool fabrics in the prototype unit, consistent results were confirmed by comparison with the mapping of cavitation intensity. Copyright © 2015 Elsevier B.V. All rights reserved.

Roller-transducer scanning of wooden pallet parts for defect detection

Treesearch

Mohammed F. Kabir; Daniel L. Schmoldt; Mark E. Schafer

2001-01-01

Ultrasonic scanning experiments were conducted on two species of pallet deckboards using rolling transducers in a pitch-catch arrangement. Sound and unsound knots, cross grain, bark pockets, holes, splits, decay, and wane were characterized using several ultrasound parameters. Almost all parameters displayed sensitivity to defects distinctly from clear wood regions—...

21 CFR Appendix B to Subpart B of... - Scope of Product Coverage

Code of Federal Regulations, 2010 CFR

2010-04-01

... Transducer ITX—Transducer, Ultrasonic, Diagnostic Diagnostic X-Ray Imaging Devices (except mammographic x-ray systems): RA 892.1600 Angiographic X-Ray System IZI—System, X-Ray, Angiographic RA 892.1650 Image-Intensified Fluoroscopic X-Ray System MQB—Solid State X-Ray Imager (Flat Panel/Digital Imager) JAA—System, X...

21 CFR Appendix B to Subpart B of... - Scope of Product Coverage

Code of Federal Regulations, 2011 CFR

2011-04-01

... Transducer ITX—Transducer, Ultrasonic, Diagnostic Diagnostic X-Ray Imaging Devices (except mammographic x-ray systems): RA 892.1600 Angiographic X-Ray System IZI—System, X-Ray, Angiographic RA 892.1650 Image-Intensified Fluoroscopic X-Ray System MQB—Solid State X-Ray Imager (Flat Panel/Digital Imager) JAA—System, X...

A macrosonic system for industrial processing

PubMed

Gallego-Juarez; Rodriguez-Corral; Riera-Franco de Sarabia E; Campos-Pozuelo; Vazquez-Martinez; Acosta-Aparicio

2000-03-01

The development of high-power applications of sonic and ultrasonic energy in industrial processing requires a great variety of practical systems with characteristics which are dependent on the effect to be exploited. Nevertheless, the majority of systems are basically constituted of a treatment chamber and one or several transducers coupled to it. Therefore, the feasibility of the application mainly depends on the efficiency of the transducer-chamber system. This paper deals with a macrosonic system which is essentially constituted of a high-power transducer with a double stepped-plate radiator coupled to a chamber of square section. The radiator, which has a rectangular shape, is placed on one face of the chamber in order to drive the inside fluid volume. The stepped profile of the radiator allows a piston-like radiation to be obtained. The radiation from the back face of the radiator is also applied to the chamber by using adequate reflectors. Transducer-chamber systems for sonic and ultrasonic frequencies have been developed with power capacities up to about 5 kW for the treatment of fluid volumes of several cubic meters. The characteristics of these systems are presented in this paper.

A Coaxial Dual-element Focused Ultrasound Probe for Guidance of Epidural Catheterization: An Experimental Study.

PubMed

Dong, Guo-Chung; Chiu, Li-Chen; Ting, Chien-Kun; Hsu, Jia-Ruei; Huang, Chih-Chung; Chang, Yin; Chen, Gin-Shin

2017-09-01

Ultrasound guidance for epidural block has improved clinical blind-trial problems but the design of present ultrasonic probes poses operating difficulty of ultrasound-guided catheterization, increasing the failure rate. The purpose of this study was to develop a novel ultrasonic probe to avoid needle contact with vertebral bone during epidural catheterization. The probe has a central circular passage for needle insertion. Two focused annular transducers are deployed around the passage for on-axis guidance. A 17-gauge insulated Tuohy needle containing the self-developed fiber-optic-modified stylet was inserted into the back of the anesthetized pig, in the lumbar region under the guidance of our ultrasonic probe. The inner transducer of the probe detected the shallow echo signals of the peak-peak amplitude of 2.8 V over L3 at the depth of 2.4 cm, and the amplitude was decreased to 0.8 V directly over the L3 to L4 interspace. The outer transducer could detect the echoes from the deeper bone at the depth of 4.5 cm, which did not appear for the inner transducer. The operator tilted the probe slightly in left-right and cranial-caudal directions until the echoes at the depth of 4.5 cm disappeared, and the epidural needle was inserted through the central passage of the probe. The needle was advanced and stopped when the epidural space was identified by optical technique. The needle passed without bone contact. Designs of the hollow probe for needle pass and dual transducers with different focal lengths for detection of shallow and deep vertebrae may benefit operation, bone/nonbone identification, and cost.

Determining the acoustic properties of the lens using a high-frequency ultrasonic needle transducer.

PubMed

Huang, Chih-Chung; Zhou, Qifa; Ameri, Hossein; Wu, Da Wei; Sun, Lei; Wang, Shyh-Hau; Humayun, Mark S; Shung, K Kirk

2007-12-01

Ultrasonic parameters including sound velocity and attenuation coefficient have recently been found to be useful in characterizing the cataract lens noninvasively. However, the regional changes of these acoustic parameters in the lens cannot be detected directly by those ultrasonic measurements. This prompted us to fabricate a 46-MHz needle transducer (lead magnesium niobate-lead titanate [PMN-PT] single crystal) with an aperture size of 0.4 mm and a diameter of 0.9 mm for directly measuring the sound velocity and frequency-dependent attenuation coefficient in lenses. These parameters have been shown to be related to the hardness of a cataract, and hence this technique may allow surgeons to detect the acoustic properties of the cataract via a small incision on the cornea before/during phacoemulsification surgery. To verify the performance of the needle transducer, experiments were performed on porcine lenses in which two types of cataracts (nucleus and cortical) were induced artificially. The needle transducer was mounted on a positioning system and its tip was inserted into the lens, allowing the anterior-to-posterior profiles of acoustic parameters along the lens axis to be obtained immediately. The experimental results show that the acoustic parameters are not constant within a single normal lens. The sound velocity and ultrasound attenuation coefficient (at 46 MHz) were 1701.2 +/- 8.4 m/s (mean +/- SD) and 9.42 +/- 0.57 dB/mm, respectively, at the nucleus, and 1597.2 +/- 9.6, 1589.3 +/- 6.1 m/s and 0.42 +/- 0.26 and 0.40 +/- 0.33 dB/mm close to the anterior and posterior capsules, respectively. Finally, the data obtained demonstrate that regional variations in the acoustic properties of lenses corresponding to the hardness of different types of cataract can be detected sensitively by a needle transducer.

A novel large thrust-weight ratio V-shaped linear ultrasonic motor with a flexible joint.

PubMed

Li, Xiaoniu; Yao, Zhiyuan; Yang, Mojian

2017-06-01

A novel large thrust-weight ratio V-shaped linear ultrasonic motor with a flexible joint is proposed in this paper. The motor is comprised of a V-shaped transducer, a slider, a clamp, and a base. The V-shaped transducer consists of two piezoelectric beams connected through a flexible joint to form an appropriate coupling angle. The V-shaped motor is operated in the coupled longitudinal-bending mode. Longitudinal and bending movements are transferred by the flexible joint between the two beams. Compared with the coupled longitudinal-bending mode of the single piezoelectric beam or the symmetrical and asymmetrical modes of the previous V-shaped transducer, the coupled longitudinal-bending mode of the V-shaped transducer with a flexible joint provides higher vibration efficiency and more convenient mode conformance adjustment. A finite element model of the V-shaped transducer is created to numerically study the influence of geometrical parameters and to determine the final geometrical parameters. In this paper, three prototypes were then fabricated and experimentally investigated. The modal test results match well with the finite element analysis. The motor mechanical output characteristics of three different coupling angles θ indicate that V-90 (θ = 90°) is the optimal angle. The mechanical output experiments conducted using the V-90 prototype (Size: 59.4 mm × 30.7 mm × 4 mm) demonstrate that the maximum unloaded speed is 1.2 m/s under a voltage of 350 Vpp, and the maximum output force is 15 N under a voltage of 300 Vpp. The proposed novel V-shaped linear ultrasonic motor has a compact size and a simple structure with a large thrust-weight ratio (0.75 N/g) and high speed.

Actuating mechanism and design of a cylindrical traveling wave ultrasonic motor using cantilever type composite transducer.

PubMed

Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

2010-04-02

Ultrasonic motors (USM) are based on the concept of driving the rotor by a mechanical vibration excited on the stator via piezoelectric effect. USM exhibit merits such as simple structure, quick response, quiet operation, self-locking when power off, nonelectromagnetic radiation and higher position accuracy. A cylindrical type traveling wave ultrasonic motor using cantilever type composite transducer was proposed in this paper. There are two cantilevers on the outside surface of cylinder, four longitudinal PZT ceramics are set between the cantilevers, and four bending PZT ceramics are set on each outside surface of cantilevers. Two degenerate flexural vibration modes spatially and temporally orthogonal to each other in the cylinder are excited by the composite transducer. In this new design, a single transducer can excite a flexural traveling wave in the cylinder. Thus, elliptical motions are achieved on the teeth. The actuating mechanism of proposed motor was analyzed. The stator was designed with FEM. The two vibration modes of stator were degenerated. Transient analysis was developed to gain the vibration characteristic of stator, and results indicate the motion trajectories of nodes on the teeth are nearly ellipses. The study results verify the feasibility of the proposed design. The wave excited in the cylinder isn't an ideal traveling wave, and the vibration amplitudes are inconsistent. The distortion of traveling wave is generated by the deformation of bending vibration mode of cylinder, which is caused by the coupling effect between the cylinder and transducer. Analysis results also prove that the objective motions of nodes on the teeth are three-dimensional vibrations. But, the vibration in axial direction is minute compared with the vibrations in circumferential and radial direction. The results of this paper can guide the development of this new type of motor.