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Sample records for bending test designed

  1. Reversal bending fatigue testing

    DOEpatents

    Wang, Jy-An John; Wang, Hong; Tan, Ting

    2014-10-21

    Embodiments for apparatuses for testing reversal bending fatigue in an elongated beam are disclosed. Embodiments are configured to be coupled to first and second end portions of the beam and to apply a bending moment to the beam and create a pure bending condition in an intermediate portion of the beam. Embodiments are further configured to cyclically alternate the direction of the bending moment applied to the beam such that the intermediate portion of the beam cyclically bends in opposite directions in a pure bending condition.

  2. Design, Manufacture and Testing of A Bend-Twist D-Spar

    SciTech Connect

    Ong, Cheng-Huat; Tsai, Stephen W.

    1999-06-01

    Studies have indicated that an adaptive wind turbine blade design can significantly enhance the performance of the wind turbine blade on energy capture and load mitigation. In order to realize the potential benefits of aeroelastic tailoring, a bend-twist D-spar, which is the backbone of a blade, was designed and fabricated to achieve the objectives of having maximum bend-twist coupling and fulfilling desirable structural properties (031 & GJ). Two bend-twist D-spars, a hybrid of glass and carbon fibers and an all-carbon D-spar, were fabricated using a bladder process. One of the D-spars, the hybrid D-spar, was subjected to a cantilever static test and modal testing. Various parameters such as materials, laminate schedule, thickness and internal rib were examined in designing a bend-twist D-spar. The fabrication tooling, the lay-up process and the joint design for two symmetric clamshells are described in this report. Finally, comparisons between the experimental test results and numerical results are presented. The comparisons indicate that the numerical analysis (static and modal analysis) agrees well with test results.

  3. Design, modeling, fabrication and testing of a MEMS capacitive bending strain sensor

    NASA Astrophysics Data System (ADS)

    Aebersold, J.; Walsh, K.; Crain, M.; Voor, M.; Martin, M.; Hnat, W.; Lin, J.; Jackson, D.; Naber, J.

    2006-04-01

    Presented herein are the design, modelling, fabrication and testing of a MEMSbased capacitive bending strain sensor utilizing a comb drive. This sensor is designed to be integrated with a telemetry system that will monitor changes in bending strain to assist orthopaedic surgeons with the diagnosis of spinal fusion. ABAQUS/CAE version 6.5 finite element analysis (FEA) modelling software was used to predict sensor actuation, capacitance output and the avoidance of material failure. Highly doped boron silicon wafers with a low resistivity were fabricated into an interdigitated finger array employing deep reactive ion etching (DRIE) to create 150 µm sidewalls with 25 µm spacing between the adjacent fingers. For testing, the sensor was adhered to a steel beam, which was subjected to four-point bending. This mechanically changed the spacing between the interdigitated fingers as a function of strain. As expected, the capacitance output increased as an inverse function of the spacing between the interdigitated fingers, beginning with an initial capacitance of 7.56 pF at the unstrained state and increasing inversely to 17.04 pF at 1571 µɛ of bending strain. The FEA and analytical models were comparable with experimental data. The largest differential of 0.65 pF or 6.33% occurred at 1000 µɛ.

  4. Design of a hydraulic bending machine

    Treesearch

    Steven G. Hankel; Marshall Begel

    2004-01-01

    To keep pace with customer demands while phasing out old and unserviceable test equipment, the staff of the Engineering Mechanics Laboratory (EML) at the USDA Forest Service, Forest Products Laboratory, designed and assembled a hydraulic bending test machine. The EML built this machine to test dimension lumber, nominal 2 in. thick and up to 12 in. deep, at spans up to...

  5. Design and validation of bending test method for characterization of miniature pediatric cortical bone specimens.

    PubMed

    Albert, Carolyne I; Jameson, John; Harris, Gerald

    2013-02-01

    Osteogenesis imperfecta is a genetic disorder of bone fragility; however, the effects of this disorder on bone material properties are not well understood. No study has yet measured bone material strength in humans with osteogenesis imperfecta. Small bone specimens are often extracted during routine fracture surgeries in children with osteogenesis imperfecta. These specimens could provide valuable insight into the effects of osteogenesis imperfecta on bone material strength; however, their small size poses a challenge to their mechanical characterization. In this study, a validated miniature three-point bending test is described that enables measurement of the flexural material properties of pediatric cortical osteotomy specimens as small as 5 mm in length. This method was validated extensively using bovine bone, and the effect of span/depth aspect ratio (5 vs 6) on the measured flexural properties was examined. The method provided reasonable results for both Young's modulus and flexural strength in bovine bone. With a span/depth ratio of 6, the median longitudinal modulus and flexural strength results were 16.1 (range: 14.4-19.3)GPa and 251 (range: 219-293)MPa, respectively. Finally, the pilot results from two osteotomy specimens from children with osteogenesis imperfecta are presented. These results provide the first measures of bone material strength in this patient population.

  6. Wire and Cable Cold Bending Test

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony

    2010-01-01

    One of the factors in assessing the applicability of wire or cable on the lunar surface is its flexibility under extreme cold conditions. Existing wire specifications did not address their mechanical behavior under cold, cryogenic temperature conditions. Therefore tests were performed to provide this information. To assess this characteristic 35 different insulated wire and cable pieces were cold soaked in liquid nitrogen. The segments were then subjected to bending and the force was recorded. Any failure of the insulation or jacketing was also documented for each sample tested. The bending force tests were performed at room temperature to provide a comparison to the change in force needed to bend the samples due to the low temperature conditions. The results from the bending tests were plotted and showed how various types of insulated wire and cable responded to bending under cold conditions. These results were then used to estimate the torque needed to unroll the wire under these low temperature conditions.

  7. Initial Ares I Bending Filter Design

    NASA Technical Reports Server (NTRS)

    Jang, Jiann-Woei; Bedrossian, Nazareth; Hall, Robert; Norris, H. Lee; Hall, Charles; Jackson, Mark

    2007-01-01

    The Ares-I launch vehicle represents a challenging flex-body structural environment for control system design. Software filtering of the inertial sensor output will be required to ensure control system stability and adequate performance. This paper presents a design methodology employing numerical optimization to develop the Ares-I bending filters. The filter design methodology was based on a numerical constrained optimization approach to maximize stability margins while meeting performance requirements. The resulting bending filter designs achieved stability by adding lag to the first structural frequency and hence phase stabilizing the first Ares-I flex mode. To minimize rigid body performance impacts, a priority was placed via constraints in the optimization algorithm to minimize bandwidth decrease with the addition of the bending filters. The bending filters provided here have been demonstrated to provide a stable first stage control system in both the frequency domain and the MSFC MAVERIC time domain simulation.

  8. Design and fabrication of a bending rotation fatigue test rig for in situ electrochemical analysis during fatigue testing of NiTi shape memory alloy wires.

    PubMed

    Neelakantan, Lakshman; Zglinski, Jenni Kristin; Frotscher, Matthias; Eggeler, Gunther

    2013-03-01

    The current investigation proposes a novel method for simultaneous assessment of the electrochemical and structural fatigue properties of nickel-titanium shape memory alloy (NiTi SMA) wires. The design and layout of an in situ electrochemical cell in a custom-made bending rotation fatigue (BRF) test rig is presented. This newly designed test rig allows performing a wide spectrum of experiments for studying the influence of fatigue on corrosion and vice versa. This can be achieved by performing ex situ and∕or in situ measurements. The versatility of the combined electrochemical∕mechanical test rig is demonstrated by studying the electrochemical behavior of NiTi SMA wires in 0.9% NaCl electrolyte under load. The ex situ measurements allow addressing various issues, for example, the influence of pre-fatigue on the localized corrosion resistance, or the influence of hydrogen on fatigue life. Ex situ experiments showed that a pre-fatigued wire is more susceptible to localized corrosion. The synergetic effect can be concluded from the polarization studies and specifically from an in situ study of the open circuit potential (OCP) transients, which sensitively react to the elementary repassivation events related to the local failure of the oxide layer. It can also be used as an indicator for identifying the onset of the fatigue failure.

  9. Design and fabrication of a bending rotation fatigue test rig for in situ electrochemical analysis during fatigue testing of NiTi shape memory alloy wires

    SciTech Connect

    Neelakantan, Lakshman; Zglinski, Jenni Kristin; Eggeler, Gunther; Frotscher, Matthias

    2013-03-15

    The current investigation proposes a novel method for simultaneous assessment of the electrochemical and structural fatigue properties of nickel-titanium shape memory alloy (NiTi SMA) wires. The design and layout of an in situ electrochemical cell in a custom-made bending rotation fatigue (BRF) test rig is presented. This newly designed test rig allows performing a wide spectrum of experiments for studying the influence of fatigue on corrosion and vice versa. This can be achieved by performing ex situ and/or in situ measurements. The versatility of the combined electrochemical/mechanical test rig is demonstrated by studying the electrochemical behavior of NiTi SMA wires in 0.9% NaCl electrolyte under load. The ex situ measurements allow addressing various issues, for example, the influence of pre-fatigue on the localized corrosion resistance, or the influence of hydrogen on fatigue life. Ex situ experiments showed that a pre-fatigued wire is more susceptible to localized corrosion. The synergetic effect can be concluded from the polarization studies and specifically from an in situ study of the open circuit potential (OCP) transients, which sensitively react to the elementary repassivation events related to the local failure of the oxide layer. It can also be used as an indicator for identifying the onset of the fatigue failure.

  10. Biomechanical evaluation of bending strength of spinal pedicle screws, including cylindrical, conical, dual core and double dual core designs using numerical simulations and mechanical tests.

    PubMed

    Amaritsakul, Yongyut; Chao, Ching-Kong; Lin, Jinn

    2014-09-01

    Pedicle screws are used for treating several types of spinal injuries. Although several commercial versions are presently available, they are mostly either fully cylindrical or fully conical. In this study, the bending strengths of seven types of commercial pedicle screws and a newly designed double dual core screw were evaluated by finite element analyses and biomechanical tests. All the screws had an outer diameter of 7 mm, and the biomechanical test consisted of a cantilever bending test in which a vertical point load was applied using a level arm of 45 mm. The boundary and loading conditions of the biomechanical tests were applied to the model used for the finite element analyses. The results showed that only the conical screws with fixed outer diameter and the new double dual core screw could withstand 1,000,000 cycles of a 50-500 N cyclic load. The new screw, however, exhibited lower stiffness than the conical screw, indicating that it could afford patients more flexible movements. Moreover, the new screw produced a level of stability comparable to that of the conical screw, and it was also significantly stronger than the other screws. The finite element analysis further revealed that the point of maximum tensile stress in the screw model was comparable to the point at which fracture occurred during the fatigue test. Copyright © 2014 IPEM. Published by Elsevier Ltd. All rights reserved.

  11. Monitoring thermoplastic composites under cyclic bending tests

    NASA Astrophysics Data System (ADS)

    Boccardi, Simone; Meola, Carosena; Carlomagno, Giovanni Maria; Simeoli, Giorgio; Acierno, Domenico; Russo, Pietro

    2016-05-01

    This work is concerned with the use of infrared thermography to visualize temperature variations linked to thermo-elastic effects developing over the surface of a specimen undergoing deflection under bending tests. Several specimens are herein considered, which involve change of matrix and/or reinforcement. More specifically, the matrix is either a pure polypropylene, or a polypropylene added with a certain percentage of compatibilizing agent; the reinforcement is made of glass, or jute. Cyclic bending tests are carried out by the aid of an electromechanical actuator. Each specimen is viewed, during deflection, from one surface by an infrared imaging device. As main finding the different specimens display surface temperature variations which depend on the type of material in terms of both matrix and reinforcement.

  12. Light-bending tests of Lorentz invariance

    SciTech Connect

    Tso, Rhondale; Bailey, Quentin G.

    2011-10-15

    Classical light-bending is investigated for weak gravitational fields in the presence of hypothetical local Lorentz violation. Using an effective field theory framework that describes general deviations from local Lorentz invariance, we derive a modified deflection angle for light passing near a massive body. The results include anisotropic effects not present for spherical sources in General Relativity as well as Weak Equivalence Principle violation. We develop an expression for the relative deflection of two distant stars that can be used to analyze data in past and future solar-system observations. The measurement sensitivities of such tests to coefficients for Lorentz violation are discussed.

  13. Testing rig for low cycle fatigue tests in combined bending and torsion

    NASA Astrophysics Data System (ADS)

    Caligiana, Gianni; Curioni, Sergio

    1992-07-01

    In order to simulate, on samples, the fatigue behavior of notched or grooved shafts used in industrial plants, a biaxal testing equipment, to transform the alternate motion of a conventional testing machine into combined torsion and bending cyclic loadings, was devised and realized. Several different amplitude ratios between torsion and bending can be obtained beyond pure torsion and pure bending. Design choices, modeling, numerical simulations and experimental verifications performed for the testing apparatus are reported. Influence of misalignment and manufacturing imperfections on the behavior of the equipment are considered.

  14. Design and development of a MEMS capacitive bending strain sensor

    NASA Astrophysics Data System (ADS)

    Aebersold, J.; Walsh, K.; Crain, M.; Martin, M.; Voor, M.; Lin, J.-T.; Jackson, D.; Hnat, W.; Naber, J.

    2006-05-01

    The design, modeling, fabrication and testing of a MEMS-based capacitive bending strain sensor utilizing a comb drive is presented. This sensor is designed to be integrated with a telemetry system that will monitor changes in bending strain to assist with the diagnosis of spinal fusion. ABAQUS/CAE finite-element analysis (FEA) software was used to predict sensor actuation, capacitance output and avoid material failure. Highly doped boron silicon wafers with a low resistivity were fabricated into an interdigitated finger array employing deep reactive ion etching (DRIE) to create 150 µm sidewalls with 25 µm spacing between the adjacent fingers. The sensor was adhered to a steel beam and subjected to four-point bending to mechanically change the spacing between the interdigitated fingers as a function of strain. As expected, the capacitance output increased as an inverse function of the spacing between the interdigitated fingers. At the unstrained state, the capacitive output was 7.56 pF and increased inversely to 17.04 pF at 1571 µɛ of bending strain. The FEA and analytical models were comparable with the largest differential of 0.65 pF or 6.33% occurring at 1000 µɛ. Advantages of this design are a dice-free process without the use of expensive silicon-on-insulator (SOI) wafers.

  15. Reversible Bending Fatigue Testing on Zry-4 Surrogate Rods

    SciTech Connect

    Wang, Jy-An John; Wang, Hong; Bevard, Bruce Balkcom; Howard, Rob L

    2014-01-01

    Testing high-burnup spent nuclear fuel (SNF) presents many challenges in areas such as specimen preparation, specimen installation, mechanical loading, load control, measurements, data acquisition, and specimen disposal because these tasks are complicated by the radioactivity of the test specimens. Research and comparison studies conducted at Oak Ridge National Laboratory (ORNL) resulted in a new concept in 2010 for a U-frame testing setup on which to perform hot-cell reversible bending fatigue testing. Subsequently, the three-dimensional finite element analysis and the engineering design of components were completed. In 2013 the ORNL team finalized the upgrade of the U-frame testing setup and the integration of the U-frame setup into a Bose dual linear motor test bench to develop a cyclic integrated reversible-bending fatigue tester (CIRFT). A final check was conducted on the CIRFT test system in August 2013, and the CIRFT was installed in the hot cell in September 2013 to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The fatigue responses of Zircaloy-4 (Zry-4) cladding and the role of pellet pellet and pellet clad interactions are critical to SNF vibration integrity, but such data are not available due to the unavailability of an effective testing system. While the deployment of the developed CIRFT test system in a hot cell will provide the opportunity to generate the data, the use of a surrogate rod has proven quite effective in identifying the underlying deformation mechanism of an SNF composite rod under an equivalent loading condition. This paper presents the experimental results of using surrogate rods under CIRFT reversible cyclic loading. Specifically, monotonic and cyclic bending tests were conducted on surrogate rods made of a Zry-4 tube and alumina pellet inserts, both with and without an epoxy bond.

  16. Security hologram foil labels with a design facilitating authenticity testing: effects of mechanical bending of substrates with the glued on holograms

    NASA Astrophysics Data System (ADS)

    Aubrecht, Ivo

    2015-05-01

    Optimal design of security holograms or diffractive optically variable image devices (DOVIDs) that would be complex enough to deter counterfeiters from attempts of mimicking but contains features readily recognizable by laymen has been addressed by many experts. This paper tries to discuss effects of mechanical bending of a flexible substrate to visual appearance of a glued-on foil DOVID. Initially plane, the DOVID is deformed to a convex- or concave-shaped curved surface. Theoretical analyses and experimental results assume the surface to be a cylindrical segment and concern rainbow-type surface-relief holograms that are recorded piecewise in a photoresist material, coated on planar and non-planar substrates.

  17. Design of micro bending deformer for optical fiber weight sensor

    NASA Astrophysics Data System (ADS)

    Ula, R. K.; Hanto, D.; Waluyo, T. B.; Adinanta, H.; Widiyatmoko, B.

    2017-04-01

    The road damage due to excessive load is one of the causes of accidents on the road. A device to measure weight of the passing vehicles needs to be planted in the road structure. Thus, a weight sensor for the passing vehicles is required. In this study, we designed a weight sensor for a static load based on a power loss due to a micro bending on the optical fiber flanked on a board. The following main components are used i.e. LED 1310 nm as a light source, a multimode fiber optic as a transmission media and a power meter for measuring power loss. This works focuses on obtaining a suitable deformer design for weight sensor. Experimental results show that deformer design with 1.5 mm single side has level of accuracy as 4.32% while the design with 1.5 mm double side has level of accuracy as 98.77%. Increasing deformer length to 2.5 mm gives 71.18% level of accuracy for single side, and 76.94% level of accuracy for double side. Micro bending design with 1.5 mm double side has a high sensitivity and it is also capable of measuring load up to 100 kg. The sensor designed has been tested for measuring the weight of motor cycle, and it can be upgraded for measuring heavy vehicles.

  18. ACHRO: A program to help design achromatic bends

    SciTech Connect

    Rusthoi, D.

    1993-01-01

    ACHRO is a very simple 2000-line. FORTRAN code that provides help for the designer of the achromatic bend. Given a beam momentum, the program calculates the required drift lengths and dipole parameters which it will apply to any one of several different types of achromats. The types of achromats that the code helps to design include the Enge dual-270,'' the Brown 2-dipole, the Leboutet 3-dipole, and the Enge 4-dipole, as well as the periodic systems which can be designed to any order in symmetric, nonsymmetric and stair-step varieties. Given the dimensions into which a bend must fit, ACHRO will calculate the geometrical parameters in an X-Y plane for a single or multiple achromat, and for achromatic S-bend'' configurations where possible. ACHRO makes it very easy to optimize a bend with respect to drift lengths and magnet parameters by allowing the user to change parameter values and see the resulting calculation. Used in conjunction with a beam-transport code, ACHRO makes it possible for a designer to consider various types of achromatic bends in the same beamline layout in order to compare important bend characteristics such as dispersion, Isochronicity, sensitivity, geometric and chromatic aberrations, aperture requirements, space for diagnostics, etc., all of which are largely a function of the geometry and the type of achromat selected.

  19. Design of cold-formed HSS channels for bending and eccentric compression: Bending in the plane of symmetry

    NASA Astrophysics Data System (ADS)

    Talja, Asko

    1992-10-01

    Open channel sections manufactured from High Strength Steels (HSS) were tested. The sections were bent in the plane of symmetry of the cross sections. The roll formed test profiles, one double U, two C and two hat profiles with yield stress of 560 to 670 N/sq mm and material thickness of 4 to 6 mm were taken from normal production. The buckling of plates or edge stiffeners was observed in some profiles. Tests for bending, eccentric compression and concentrated load were made. The test results together with other tests results from literature are compared with the design resistances determined according to the proposed design method. The method is satisfactory for normal design, but in some cases it was found to be too conservative. Comparisons with the other test results confirmed that the accuracy of the design rules do not depend on the yield strength or wall thickness.

  20. Tension bending ratcheting tests of 304 stainless steel

    SciTech Connect

    Larson, L.D.; Jones, D.P.; Rapp, D.G.

    1996-12-31

    This paper discusses results of an experimental program conducted to investigate the strain ratcheting behavior of 304 stainless steel under various combinations of applied membrane load and displacement controlled cyclic bending strain. Tests were performed on uniaxial specimens at temperatures of 70 F (21 C) and 550 F (288 C). Bending strain, ratchet strain and axial displacement of the specimens were monitored throughout the tests. Membrane stress to monotonic yield stress ratios of 2/3, 1/2, and 1/3 were tested with pseudo-elastic bending stress to yield stress ratios ranging from 1.4 to 10.7. Test output was in the form of plots of cumulative axial membrane strain versus cycles up to the point of shakedown, i.e., the point at which no additional progressive strain was observed. Shakedown was demonstrated in the 500 F tests but not the room temperature tests. The 550 F results are shown in terms of shakedown membrane strain versus equivalent bending stress ratio for each of the tested membrane stress ratios. The cyclic and monotonic stress-strain curves for the test materials are presented to enable the use of various models for predicting the ratcheting and shakedown behavior. The results may be used to develop improved ratcheting and shakedown rules permitting a relaxation of the traditional ratcheting rules in the ASME Boiler and Pressure Vessel Code.

  1. Modelling The Bending Test Behaviour Of Carbon Fibre Reinforced SiC By Finite Element Method

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Koch, D.; Voggenreiter, H.

    2012-07-01

    Liquid silicon infiltrated carbon fibre reinforced SiC, has shown to be a high-potential material for thermal protection systems. The tensile and bending behaviour of the ceramic-matrix composite, C/C-SiC, were investigated in varying orientations relative to the 0/90° woven carbon fibres. The ratio of bending to tensile strength was about 1.7 to 2 depending on the loading direction. With the goal to understand this large difference finite element analyses (FEA) of the bending tests were performed. The different stress-strain behaviour of C/C-SiC under tensile and compression load were included in the FEA. Additionally the bending failure of the CMC-material was modelled by Cohesive Zone Elements (CZE) accounting for the directional tensile strength and Work of Fracture (WOF). The WOF was determined by Single Edge Notched Bending (SENB) tests. Comparable results from FEA and bending test were achieved. The presented approach could also be adapted for the design of C/C-SiC-components and structures.

  2. Comparing Rotary Bend Wire Fatigue Test Methods at Different Test Speeds

    NASA Astrophysics Data System (ADS)

    Weaver, Jason D.; Gutierrez, Erick J.

    2015-12-01

    Given its relatively simple setup and ability to produce results quickly, rotary bend fatigue testing is becoming commonplace in the medical device industry and is the subject of a new standard test method ASTM E2948-14. Although some research has been conducted to determine if results differ for different rotary bend fatigue test setups or test speeds, these parameters have not been extensively studied together. In this work, we investigate the effects of these two parameters on the fatigue life of three commonly used medical device alloys (ASTM F2063 nitinol, ASTM F138 stainless steel, and ASTM F1058 cobalt chromium). Results with three different rotary bend fatigue test setups revealed no difference in fatigue life among those setups. Increasing test speed, however, between 100 and 35,000 RPM led to an increased fatigue life for all three alloys studied (average number of cycles to fracture increased between 2.0 and 5.1 times between slowest and fastest test speed). Supplemental uniaxial tension tests of stainless steel wire at varying strain rates showed a strain rate dependence in the mechanical response which could in part explain the increased fatigue life at faster test speeds. How exactly strain rate dependence might affect the fatigue properties of different alloys at different alternating strain values requires further study. Given the difference in loading rates between benchtop fatigue tests and in vivo deformations, the potential for strain rate dependence should be considered when designing durability tests for medical devices and in extrapolating results of those tests to in vivo performance.

  3. Testing Aerospace Gears for Bending Fatigue, Pitting, and Scuffing

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy; Anderson, Cody; Shareef, Iqbal; Fetty, Jason

    2017-01-01

    This work was motivated by the goal to increase the power to weight ratio of rotorcraft drive systems. Experiments were conducted to establish the performance of gears made from an aerospace alloy used in production aircraft. Bending fatigue, pitting, and scuffing test procedures and results are documented. The data establishes a baseline for evaluation of new technologies. Recommendations are made to improve test procedures for future work.

  4. Fatigue Testing of TBC on Structural Steel by Cyclic Bending

    NASA Astrophysics Data System (ADS)

    Musalek, Radek; Kovarik, Ondrej; Medricky, Jan; Curry, Nicholas; Bjorklund, Stefan; Nylen, Per

    2015-01-01

    For applications with variable loading, fatigue performance of coated parts is of utmost importance. In this study, fatigue performance of conventional structural steel coated with thermal barrier coating (TBC) was evaluated in cyclic bending mode by "SF-Test" device. Testing was carried out at each stage of the TBC preparation process, i.e., for as-received and grit-blasted substrates, as well as for samples with Ni-based bond-coat and complete TBC: bond-coat with YSZ-based top-coat. Comparison of results obtained for different loading amplitudes supplemented by fractographic analysis enabled identification of dominating failure mechanisms and demonstrated applicability of the high-frequency resonant bending test for evaluation of fatigue resistance alteration at each stage of the TBC deposition process.

  5. Compression After Impact Testing of Sandwich Structures Using the Four Point Bend Test

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.; Gregory, Elizabeth; Jackson, Justin; Kenworthy, Devon

    2008-01-01

    For many composite laminated structures, the design is driven by data obtained from Compression after Impact (CAI) testing. There currently is no standard for CAI testing of sandwich structures although there is one for solid laminates of a certain thickness and lay-up configuration. Most sandwich CAI testing has followed the basic technique of this standard where the loaded ends are precision machined and placed between two platens and compressed until failure. If little or no damage is present during the compression tests, the loaded ends may need to be potted to prevent end brooming. By putting a sandwich beam in a four point bend configuration, the region between the inner supports is put under a compressive load and a sandwich laminate with damage can be tested in this manner without the need for precision machining. Also, specimens with no damage can be taken to failure so direct comparisons between damaged and undamaged strength can be made. Data is presented that demonstrates the four point bend CAI test and is compared with end loaded compression tests of the same sandwich structure.

  6. Bending continuous structures with SMAs: a novel robotic fish design.

    PubMed

    Rossi, C; Colorado, J; Coral, W; Barrientos, A

    2011-12-01

    In this paper, we describe our research on bio-inspired locomotion systems using deformable structures and smart materials, concretely shape memory alloys (SMAs). These types of materials allow us to explore the possibility of building motor-less and gear-less robots. A swimming underwater fish-like robot has been developed whose movements are generated using SMAs. These actuators are suitable for bending the continuous backbone of the fish, which in turn causes a change in the curvature of the body. This type of structural arrangement is inspired by fish red muscles, which are mainly recruited during steady swimming for the bending of a flexible but nearly incompressible structure such as the fishbone. This paper reviews the design process of these bio-inspired structures, from the motivations and physiological inspiration to the mechatronics design, control and simulations, leading to actual experimental trials and results. The focus of this work is to present the mechanisms by which standard swimming patterns can be reproduced with the proposed design. Moreover, the performance of the SMA-based actuators' control in terms of actuation speed and position accuracy is also addressed.

  7. Analysis of three-point-bend test for materials with unequal tension and compression properties

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1974-01-01

    An analysis capability is described for the three-point-bend test applicable to materials of linear but unequal tensile and compressive stress-strain relations. The capability consists of numerous equations of simple form and their graphical representation. Procedures are described to examine the local stress concentrations and failure modes initiation. Examples are given to illustrate the usefulness and ease of application of the capability. Comparisons are made with materials which have equal tensile and compressive properties. The results indicate possible underestimates for flexural modulus or strength ranging from 25 to 50 percent greater than values predicted when accounting for unequal properties. The capability can also be used to reduce test data from three-point-bending tests, extract material properties useful in design from these test data, select test specimen dimensions, and size structural members.

  8. Design of a Variable Thickness Plate to Focus Bending Waves

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Lin, Sz-Chin Steven; Cabell, Randolph H.; Huang, Tony Jun

    2012-01-01

    This paper describes the design of a thin plate whose thickness is tailored in order to focus bending waves to a desired location on the plate. Focusing is achieved by smoothly varying the thickness of the plate to create a type of lens, which focuses structural-borne energy. Damping treatment can then be positioned at the focal point to efficiently dissipate energy with a minimum amount of treatment. Numerical simulations of both bounded and unbounded plates show that the design is effective over a broad frequency range, focusing traveling waves to the same region of the plate regardless of frequency. This paper also quantifies the additional energy dissipated by local damping treatment installed on a variable thickness plate relative to a uniform plate.

  9. Design Optimization for Superconducting Bending Magnets using Pareto Front Curve

    NASA Astrophysics Data System (ADS)

    Murata, Yukihiro; Abe, Mitsushi; Ando, Ryuya

    2017-09-01

    A novel limit design method for superconducting magnets is presented. It is particularly suitable for ion core magnets such as those used in accelerator magnets. In general, a stochastic optimization whose objective functions consist of values, e.g., the magnetic field, experience field of superconducting coils, current density, and multipole field integral, is often used. However, it is well known that the obtained solution strongly depends on the initial one. Furthermore, once the calculation model is fixed, the range of solutions is also fixed, i.e., there are times when it may be impossible to find the global optimum solution even with a lot of parameter sweeps. In this study, we draw the Pareto front curve to obtain the range and infer whether the solution is an optimum one. In addition, the Pareto front curve indicates the neighborhood solution that is substituted for the initial one. After this process a stochastic optimization is implemented with its initial design parameters. To confirm the validity, we designed a superconducting bending magnet, and it showed that this method works well.

  10. Waveguide Parameter Design of Graded-Index Plastic Optical Fibers for Bending-Loss Reduction

    NASA Astrophysics Data System (ADS)

    Makino, Kenji; Ishigure, Takaaki; Koike, Yasuhiro

    2006-05-01

    The waveguide structure of graded-index plastic optical fibers (GI POFs), such as index profile, numerical aperture (NA), and core diameter, is appropriately designed for eliminating bending losses, even under a severe bending condition. The bending loss of GI POFs under a severe bending condition is drastically reduced when the core diameter is smaller than 200 µm and when the NA is higher than 0.25. The bending loss of GI POFs even under a severe bending condition vanishes with a core diameter of 200 µm and an NA of 0.24. It is experimentally confirmed for the first time that the mode coupling due to the bending induces the bending loss. The mode coupling strength before the fiber is bent affects the bending loss seriously. Moreover, the mode-coupling strength is evaluated by the propagation constant difference Δβ between the adjacent modes. The Δβ value, which is a function of the core diameter and NA, affects the bending loss. Therefore, based on the calculation of the Δβ, we propose a guideline for the appropriate design of waveguide parameters for GI POF, in order to suppress the bending loss.

  11. Wire-bending test as a predictor of preclinical performance by dental students.

    PubMed

    Kao, E C; Ngan, P W; Wilson, S; Kunovich, R

    1990-10-01

    Traditional Dental Aptitude Test and academic grade point average have been shown to be poor predictors of clinical performance by dental students. To refine predictors of psychomotor skills, a wire-bending test was given to 105 freshmen at the beginning of their dental education. Grades from seven restorative preclinical courses in their freshman and sophomore years were compared to scores on wire bending and the three traditional predictors: GPA, academic aptitude, and perceptual aptitude scores. Wire-bending scores correlated significantly with six out of seven preclinical restorative courses. The predictive power for preclinical performance was doubled when wire bending was added to traditional predictors in stepwise multiple regression analysis. Wire-bending scores identified students of low performance. These preliminary results suggest that the wire-bending test shows some potential as a screening test for identifying students who may hae psychomotor difficulties, early in their dental education.

  12. Tension and Bending Testing of an Integral T-Cap for Stitched Composite Airframe Joints

    NASA Technical Reports Server (NTRS)

    Lovejoy, Andrew E.; Leone, Frank A., Jr.

    2016-01-01

    The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a structural concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body aircraft configuration. An important design feature required for assembly is the integrally stitched T-cap, which provides connectivity of the corner (orthogonal) joint between adjacent panels. A series of tests were conducted on T-cap test articles, with and without a rod stiffener penetrating the T-cap web, under tension (pull-off) and bending loads. Three designs were tested, including the baseline design used in large-scale test articles. The baseline had only the manufacturing stitch row adjacent to the fillet at the base of the T-cap web. Two new designs added stitching rows to the T-cap web at either 0.5- or 1.0-inch spacing along the height of the web. Testing was conducted at NASA Langley Research Center to determine the behavior of the T-cap region resulting from the applied loading. Results show that stitching arrests the initial delamination failures so that the maximum strength capability exceeds the load at which the initial delaminations develop. However, it was seen that the added web stitching had very little effect on the initial delamination failure load, but actually decreased the initial delamination failure load for tension loading of test articles without a stiffener passing through the web. Additionally, the added web stitching only increased the maximum load capability by between 1% and 12.5%. The presence of the stiffener, however, did increase the initial and maximum loads for both tension and bending loading as compared to the stringerless baseline design. Based on the results of the few samples tested, the additional stitching in the T-cap web showed little advantage over the baseline design in terms of structural failure at the T-cap web/skin junction for the current test articles.

  13. Predicting bending strength of fire-retardant-treated plywood from screw-withdrawal tests

    Treesearch

    J. E. Winandy; P. K. Lebow; W. Nelson

    This report describes the development of a test method and predictive model to estimate the residual bending strength of fire-retardant-treated plywood roof sheathing from measurement of screw-withdrawal force. The preferred test methodology is described in detail. Models were developed to predict loss in mean and lower prediction bounds for plywood bending strength as...

  14. A New High-Speed, High-Cycle, Gear-Tooth Bending Fatigue Test Capability

    NASA Technical Reports Server (NTRS)

    Stringer, David B.; Dykas, Brian D.; LaBerge, Kelsen E.; Zakrajsek, Andrew J.; Handschuh, Robert F.

    2011-01-01

    A new high-speed test capability for determining the high cycle bending-fatigue characteristics of gear teeth has been developed. Experiments were performed in the test facility using a standard spur gear test specimens designed for use in NASA Glenn s drive system test facilities. These tests varied in load condition and cycle-rate. The cycle-rate varied from 50 to 1000 Hz. The loads varied from high-stress, low-cycle loads to near infinite life conditions. Over 100 tests were conducted using AISI 9310 steel spur gear specimen. These results were then compared to previous data in the literature for correlation. Additionally, a cycle-rate sensitivity analysis was conducted by grouping the results according to cycle-rate and comparing the data sets. Methods used to study and verify load-path and facility dynamics are also discussed.

  15. SiC-CMC-Zircaloy-4 Nuclear Fuel Cladding Performance during 4-Point Tubular Bend Testing

    SciTech Connect

    IJ van Rooyen; WR Lloyd; TL Trowbridge; SR Novascone; KM Wendt; SM Bragg-Sitton

    2013-09-01

    The U.S. Department of Energy Office of Nuclear Energy (DOE NE) established the Light Water Reactor Sustainability (LWRS) program to develop technologies and other solutions to improve the reliability, sustain the safety, and extend the life of current reactors. The Advanced LWR Nuclear Fuel Development Pathway in the LWRS program encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. Recent investigations of potential options for “accident tolerant” nuclear fuel systems point to the potential benefits of silicon carbide (SiC) cladding. One of the proposed SiC-based fuel cladding designs being investigated incorporates a SiC ceramic matrix composite (CMC) as a structural material supplementing an internal Zircaloy-4 (Zr-4) liner tube, referred to as the hybrid clad design. Characterization of the advanced cladding designs will include a number of out-of-pile (nonnuclear) tests, followed by in-pile irradiation testing of the most promising designs. One of the out-of-pile characterization tests provides measurement of the mechanical properties of the cladding tube using four point bend testing. Although the material properties of the different subsystems (materials) will be determined separately, in this paper we present results of 4-point bending tests performed on fully assembled hybrid cladding tube mock-ups, an assembled Zr-4 cladding tube mock-up as a standard and initial testing results on bare SiC-CMC sleeves to assist in defining design parameters. The hybrid mock-up samples incorporated SiC-CMC sleeves fabricated with 7 polymer impregnation and pyrolysis (PIP) cycles. To provide comparative information; both 1- and 2-ply braided SiC-CMC sleeves were used in this development study. Preliminary stress simulations were performed using the BISON nuclear fuel performance code to show the stress distribution differences for varying lengths between loading points

  16. Ares-I Bending Filter Design using a Constrained Optimization Approach

    NASA Technical Reports Server (NTRS)

    Hall, Charles; Jang, Jiann-Woei; Hall, Robert; Bedrossian, Nazareth

    2008-01-01

    The Ares-I launch vehicle represents a challenging flex-body structural environment for control system design. Software filtering of the inertial sensor output is required to ensure adequate stable response to guidance commands while minimizing trajectory deviations. This paper presents a design methodology employing numerical optimization to develop the Ares-I bending filters. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics, propellant slosh, and flex. Under the assumption that the Ares-I time-varying dynamics and control system can be frozen over a short period of time, the bending filters are designed to stabilize all the selected frozen-time launch control systems in the presence of parameter uncertainty. To ensure adequate response to guidance command, step response specifications are introduced as constraints in the optimization problem. Imposing these constrains minimizes performance degradation caused by the addition of the bending filters. The first stage bending filter design achieves stability by adding lag to the first structural frequency to phase stabilize the first flex mode while gain stabilizing the higher modes. The upper stage bending filter design gain stabilizes all the flex bending modes. The bending filter designs provided here have been demonstrated to provide stable first and second stage control systems in both Draper Ares Stability Analysis Tool (ASAT) and the MSFC MAVERIC 6DOF nonlinear time domain simulation.

  17. Four-point Bend Testing of Irradiated Monolithic U-10Mo Fuel

    SciTech Connect

    Rabin, B. H.; Lloyd, W. R.; Schulthess, J. L.; Wright, J. K.; Lind, R. P.; Scott, L.; Wachs, K. M.

    2015-03-01

    This paper presents results of recently completed studies aimed at characterizing the mechanical properties of irradiated U-10Mo fuel in support of monolithic base fuel qualification. Mechanical properties were evaluated in four-point bending. Specimens were taken from fuel plates irradiated in the RERTR-12 and AFIP-6 Mk. II irradiation campaigns, and tests were conducted in the Hot Fuel Examination Facility (HFEF) at Idaho National Laboratory (INL). The monolithic fuel plates consist of a U-10Mo fuel meat covered with a Zr diffusion barrier layer fabricated by co-rolling, clad in 6061 Al using a hot isostatic press (HIP) bonding process. Specimens exhibited nominal (fresh) fuel meat thickness ranging from 0.25 mm to 0.64 mm, and fuel plate average burnup ranged from approximately 0.4 x 1021 fissions/cm3 to 6.0 x 1021 fissions/cm3. After sectioning the fuel plates, the 6061 Al cladding was removed by dissolution in concentrated NaOH. Pre- and post-dissolution dimensional inspections were conducted on test specimens to facilitate accurate analysis of bend test results. Four-point bend testing was conducted on the HFEF Remote Load Frame at a crosshead speed of 0.1 mm/min using custom-designed test fixtures and calibrated load cells. All specimens exhibited substantially linear elastic behavior and failed in a brittle manner. The influence of burnup on the observed slope of the stress-strain curve and the calculated fracture strength is discussed.

  18. Strength Tests of Thin-walled Duralumin Cylinders in Pure Bending

    NASA Technical Reports Server (NTRS)

    Lundquist, Eugene E

    1933-01-01

    This report is the third of a series presenting the results of strengths tests on thin-walled cylinders and truncated cones of circular and elliptic section; it includes the results obtained from pure bending tests on 58 thin-walled duralumin cylinders of circular section with ends clamped to rigid bulkheads. The tests show that the stress on the extreme fiber at failure as calculated by the ordinary theory of bending is from 30 to 80 percent greater than the compressive stress at failure for thin-walled cylinders in compression. The tests also show that length/radius ratio has no consistent effect upon the bending strength and that the size of the wrinkles that form on the compression half of a cylinder in bending is approximately equal to the size of the wrinkles that form in the complete circumference of a cylinder of the same dimensions in compression.

  19. Reversal bending fatigue test system for investigating vibration integrity of spent nuclear fuel during transportation

    SciTech Connect

    Wang, Jy -An; Wang, Hong; Bevard, Bruce Balkcom; Howard, Rob L.; Flanagan, Michelle E.

    2014-09-01

    Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During transportation, SNF experiences unique conditions and challenges to cladding integrity due to the vibrational and impact loading during road or rail shipment. Oak Ridge National Laboratory (ORNL) has been developing testing capabilities that can be used to improve the understanding of the impacts on SNF integrity due to vibration loading, especially for high burn-up SNF in normal transportation operation conditions. This information can be used to meet the nuclear industry and U.S.Nuclear Regulatory Commission needs in the area of safety and security of SNF storage and transportation operations. The ORNL developed test system can perform reversal bending fatigue testing to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The testing apparatus is also designed to meet the challenges of hot cell operation, including remote installation and detachment of the SNF test specimen, in situ test specimen deformation measurement, and implementation of a driving system suitable for use in a hot cell. The system contains a U frame set-up equipped with uniquely designed grip rigs to protect the SNF rod sample and to ensure valid test results, and uses three specially designed linear variable differential transformers to obtain the in situ curvature measurement. A variety of surrogate test rods have been used to develop and calibrate the test system as well as in performing a series of systematic cyclic fatigue tests. The surrogate rods include stainless steel (SS) cladding, SS cladding with cast epoxy and SS cladding with alumina pellet inserts simulating fuel pellets. Testing to date has shown that the interface bonding between the SS cladding and the alumina pellets has a significant impact on the bending response of the test rods as well as their fatigue strength. The

  20. Reversal bending fatigue test system for investigating vibration integrity of spent nuclear fuel during transportation

    DOE PAGES

    Wang, Jy -An; Wang, Hong; Bevard, Bruce Balkcom; ...

    2014-09-01

    Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During transportation, SNF experiences unique conditions and challenges to cladding integrity due to the vibrational and impact loading during road or rail shipment. Oak Ridge National Laboratory (ORNL) has been developing testing capabilities that can be used to improve the understanding of the impacts on SNF integrity due to vibration loading, especially for high burn-up SNF in normal transportation operation conditions. This information can be used to meet the nuclear industry and U.S.Nuclear Regulatory Commission needs in the areamore » of safety and security of SNF storage and transportation operations. The ORNL developed test system can perform reversal bending fatigue testing to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The testing apparatus is also designed to meet the challenges of hot cell operation, including remote installation and detachment of the SNF test specimen, in situ test specimen deformation measurement, and implementation of a driving system suitable for use in a hot cell. The system contains a U frame set-up equipped with uniquely designed grip rigs to protect the SNF rod sample and to ensure valid test results, and uses three specially designed linear variable differential transformers to obtain the in situ curvature measurement. A variety of surrogate test rods have been used to develop and calibrate the test system as well as in performing a series of systematic cyclic fatigue tests. The surrogate rods include stainless steel (SS) cladding, SS cladding with cast epoxy and SS cladding with alumina pellet inserts simulating fuel pellets. Testing to date has shown that the interface bonding between the SS cladding and the alumina pellets has a significant impact on the bending response of the test rods as well as their fatigue strength

  1. Reversible Bending Fatigue Test System for Investigating Vibration Integrity of Spent Nuclear Fuel during Transportation

    SciTech Connect

    Wang, Jy-An John; Wang, Hong; Bevard, Bruce Balkcom; Howard, Rob L; Flanagan, Michelle

    2013-01-01

    Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During transportation, SNF experiences unique conditions and challenges to cladding integrity due to the vibrational and impact loading during road or rail shipment. Oak Ridge National Laboratory (ORNL) has been developing testing capabilities that can be used to improve the understanding of the impacts on SNF integrity due to vibration loading, especially for high burn-up SNF in normal transportation operation conditions. This information can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in the area of safety and security of spent nuclear fuel storage and transport operations. The ORNL developed test system can perform reversible-bending fatigue testing to evaluate both the static and dynamic mechanical response of SNF rods under simulated loads. The testing apparatus is also designed to meet the challenges of hot-cell operation, including remote installation and detachment of the SNF test specimen, in-situ test specimen deformation measurement, and implementation of a driving system suitable for use in a hot cell. The system contains a U-frame set-up equipped with uniquely designed grip rigs, to protect SNF rod and to ensure valid test results, and use of 3 specially designed LVDTs to obtain the in-situ curvature measurement. A variety of surrogate test rods have been used to develop and calibrate the test system as well as in performing a series of systematic cyclic fatigue tests. The surrogate rods include stainless steel (SS) cladding, SS cladding with cast epoxy, and SS cladding with alumina pellets inserts simulating fuel pellets. Testing to date has shown that the interface bonding between the SS cladding and the alumina pellets has a significant impact on the bending response of the test rods as well as their fatigue strength. The failure behaviors observed from

  2. A new compression design that increases proximal locking screw bending resistance in femur compression nails.

    PubMed

    Karaarslan, Ahmet Adnan; Karakaşli, Ahmet; Karci, Tolga; Aycan, Hakan; Yildirim, Serhat; Sesli, Erhan

    2015-06-01

    The aim is to present our new method of compression, a compression tube instead of conventional compression screw and to investigate the difference of proximal locking screw bending resistance between compression screw application (6 mm wide contact) and compression tube (two contact points with 13 mm gap) application. We formed six groups each consisting of 10 proximal locking screws. On metal cylinder representing lesser trochanter level, we performed 3-point bending tests with compression screw and with compression tube. We determined the yield points of the screws in 3-point bending tests using an axial compression testing machine. We determined the yield point of 5 mm screws as 1963±53 N (mean±SD) with compression screw, and as 2929±140 N with compression tubes. We found 51% more locking screw bending resistance with compression tube than with compression screw (p=0,000). Therefore compression tubes instead of compression screw must be preferred at femur compression nails.

  3. TEST SYSTEM FOR EVALUATING SPENT NUCLEAR FUEL BENDING STIFFNESS AND VIBRATION INTEGRITY

    SciTech Connect

    Wang, Jy-An John; Wang, Hong; Bevard, Bruce Balkcom; Howard, Rob L; Flanagan, Michelle

    2013-01-01

    Transportation packages for spent nuclear fuel (SNF) must meet safety requirements specified by federal regulations. For normal conditions of transport, vibration loads incident to transport must be considered. This is particularly relevant for high-burnup fuel (>45 GWd/MTU). As the burnup of the fuel increases, a number of changes occur that may affect the performance of the fuel and cladding in storage and during transportation. The mechanical properties of high-burnup de-fueled cladding have been previously studied by subjecting defueled cladding tubes to longitudinal (axial) tensile tests, ring-stretch tests, ring-compression tests, and biaxial tube burst tests. The objective of this study is to investigate the mechanical properties and behavior of both the cladding and the fuel in it under vibration/cyclic loads similar to the sustained vibration loads experienced during normal transport. The vibration loads to SNF rods during transportation can be characterized by dynamic, cyclic, bending loads. The transient vibration signals in a specified transport environment can be analyzed, and frequency, amplitude and phase components can be identified. The methodology being implemented is a novel approach to study the vibration integrity of actual SNF rod segments through testing and evaluating the fatigue performance of SNF rods at defined frequencies. Oak Ridge National Laboratory (ORNL) has developed a bending fatigue system to evaluate the response of the SNF rods to vibration loads. A three-point deflection measurement technique using linear variable differential transformers is used to characterize the bending rod curvature, and electromagnetic force linear motors are used as the driving system for mechanical loading. ORNL plans to use the test system in a hot cell for SNF vibration testing on high burnup, irradiated fuel to evaluate the pellet-clad interaction and bonding on the effective lifetime of fuel-clad structure bending fatigue performance. Technical

  4. Design and fabrication of Rene 41 advanced structural panels. [their performance under axial compression, shear, and bending loads

    NASA Technical Reports Server (NTRS)

    Greene, B. E.; Northrup, R. F.

    1975-01-01

    The efficiency was investigated of curved elements in the design of lightweight structural panels under combined loads of axial compression, inplane shear, and bending. The application is described of technology generated in the initial aluminum program to the design and fabrication of Rene 41 panels for subsequent performance tests at elevated temperature. Optimum designs for two panel configurations are presented. The designs are applicable to hypersonic airplane wing structure, and are designed specifically for testing at elevated temperature in the hypersonic wing test structure located at the NASA Flight Research Center. Fabrication methods developed to produce the Rene panels are described, and test results of smaller structural element specimens are presented to verify the design and fabrication methods used. Predicted strengths of the panels under several proposed elevated temperature test load conditions are presented.

  5. Comparison of ring compression testing to three point bend testing for unirradiated ZIRLO cladding

    SciTech Connect

    None, None

    2015-04-01

    Safe shipment and storage of nuclear reactor discharged fuel requires an understanding of how the fuel may perform under the various conditions that can be encountered. One specific focus of concern is performance during a shipment drop accident. Tests at Savannah River National Laboratory (SRNL) are being performed to characterize the properties of fuel clad relative to a mechanical accident condition such as a container drop. Unirradiated ZIRLO tubing samples have been charged with a range of hydride levels to simulate actual fuel rod levels. Samples of the hydrogen charged tubes were exposed to a radial hydride growth treatment (RHGT) consisting of heating to 400°C, applying initial hoop stresses of 90 to 170 MPa with controlled cooling and producing hydride precipitates. Initial samples have been tested using both a) ring compression test (RCT) which is shown to be sensitive to radial hydride and b) three-point bend tests which are less sensitive to radial hydride effects. Hydrides are generated in Zirconium based fuel cladding as a result of coolant (water) oxidation of the clad, hydrogen release, and a portion of the released (nascent) hydrogen absorbed into the clad and eventually exceeding the hydrogen solubility limit. The orientation of the hydrides relative to the subsequent normal and accident strains has a significant impact on the failure susceptability. In this study the impacts of stress, temperature and hydrogen levels are evaluated in reference to the propensity for hydride reorientation from the circumferential to the radial orientation. In addition the effects of radial hydrides on the Quasi Ductile Brittle Transition Temperature (DBTT) were measured. The results suggest that a) the severity of the radial hydride impact is related to the hydrogen level-peak temperature combination (for example at a peak drying temperature of 400°C; 800 PPM hydrogen has less of an impact/ less radial hydride fraction than 200 PPM hydrogen for the same thermal

  6. A testing technique allowing cyclic application of axial, bending, and torque loads to fracture plates to examine screw loosening.

    PubMed

    Szivek, J A; Yapp, R A

    1989-04-01

    Orthopaedic internal fracture fixation plates are subjected to combined axial, bending, and torsional loads in vivo which can cause screw loosening and implant failure. This paper outlines a relatively simple technique which allows controlled application of combined axial, bending, and torsional loading to examine the loosening rate of cortical screws used to attach these plates. Fiber reinforced polycarbonate rods with a tensile strength similar to that of cortical bone were cut at half their length to simulate fractured tibii. These were compression plated using a standardized technique and placed in a loading fixture. Joint loads at the knee determined from force plate analysis and statics were applied to a plated fixture during testing. The design of the fixture allowed adjustment of the proportion of bending and torsional loads applied to the test samples. It also allowed a reproducible means of applying a predetermined axial, bending, and torsional load. Screw loosening following cyclical loading was evaluated by measuring the amount of angular displacement required to retighten screws to a prescribed torque value. A torque wrench was modified to allow the measurement of these displacements.

  7. The History of Structural Fatigue Testing at Fishermans Bend Australia

    DTIC Science & Technology

    2005-10-01

    Test GAF Government Aircraft Factories IFOSTP International Follow - On Structural Test Project LEX Leading Edge...project known as the International Follow - On DSTO-TR-1773 34 Structural Test Project ( IFOSTP ). IFOSTP consisted of three separate FSFTs supported by...J. Roussel, L. Molent, A.D. Graham and N. Schmidt, The Canadian and Australian F/A-18 International Follow - On Structural

  8. Structural factor in bending testing of fivefold twinned nanowires revealed by finite element analysis

    NASA Astrophysics Data System (ADS)

    Mets, Magnus; Antsov, Mikk; Zadin, Vahur; Dorogin, Leonid M.; Aabloo, Alvo; Polyakov, Boris; Lõhmus, Rünno; Vlassov, Sergei

    2016-11-01

    In this study, we performed finite element method simulations to investigate the effect of the structure on the elastic response of Ag and Au nanowires (NWs) with a fivefold twinned crystal structure in bending tests. Two different models of a pentagonal NW were created: a ‘uniform model’ having an isotropic continuous structure and a ‘segmented model’ consisting of five anisotropic domains. Two asymmetrical mechanical test configurations were simulated: cantilevered beam bending and 3-point bending. The dimensions of the NW, the test configurations, as well as the force and the displacement ranges were based on the previously obtained experimental data. The results of the simulations demonstrated that the segmented model was stiffer than the uniform one in both of the bending tests. The effect was more pronounced for the cantilevered beam bending configuration. This fact should be taken into account in the interpretation of the increased measured Young’s modulus of pentagonal NWs in comparison to the elasticity of the same material in bulk form.

  9. Design, fabrication, and characterization of Si-based ARROW photonic crystal bend waveguides and power splitters.

    PubMed

    Chen, Jian-Hua; Huang, Yang-Tung; Yang, Yu-Lin; Lu, Ming-Feng; Shieh, Jia-Min

    2012-08-20

    Silicon-based (Si-based) photonic crystal waveguide based on antiresonant reflecting optical waveguide (ARROW PCW) structures consisting of 60° bends and Y-branch power splitters were designed and first efficiently fabricated and characterized. The ARROW structure has a relatively large core size suitable for efficient coupling with a single-mode fiber. Simple capsule-shaped topography defects at 60° photonic crystal (PC) bend corners and Y-branch PC power splitters were used for increasing the broadband light transmission. In the preliminary measurements, the propagation losses of the ARROW PC straight waveguides lower than 2 dB/mm with a long length of 1500 μm were achieved. The average bend loss of 60° PC bend waveguides was lower than 3 dB/bend. For the Y-branch PC power splitters, the average power imbalance was lower than 0.6 dB. The results show that our fabricated Si-based ARROW PCWs with 60° bends and Y-branch structures can provide good light transmission and power-splitting ability.

  10. Design and optimization of a bend-and-sweep compliant mechanism

    NASA Astrophysics Data System (ADS)

    Tummala, Y.; Frecker, M. I.; Wissa, A. A.; Hubbard, J. E., Jr.

    2013-09-01

    A novel contact aided compliant mechanism called bend-and-sweep compliant mechanism is presented in this paper. This mechanism has nonlinear stiffness properties in two orthogonal directions. An angled compliant joint (ACJ) is the fundamental element of this mechanism. Geometric parameters of ACJs determine the stiffness of the compliant mechanism. This paper presents the design and optimization of bend-and-sweep compliant mechanism. A multi-objective optimization problem was formulated for design optimization of the bend-and-sweep compliant mechanism. The objectives of the optimization problem were to maximize or minimize the bending and sweep displacements, depending on the situation, while minimizing the von Mises stress and mass of each mechanism. This optimization problem was solved using NSGA-II (a genetic algorithm). The results of this optimization for a single ACJ during upstroke and downstroke are presented in this paper. Results of two different loading conditions used during optimization of a single ACJ for upstroke are presented. Finally, optimization results comparing the performance of compliant mechanisms with one and two ACJs are also presented. It can be inferred from these results that the number of ACJs and the design of each ACJ determines the stiffness of the bend-and-sweep compliant mechanism. These mechanisms can be used in various applications. The goal of this research is to improve the performance of ornithopters by passively morphing their wings. In order to achieve a bio-inspired wing gait called continuous vortex gait, the wings of the ornithopter need to bend, and sweep simultaneously. This can be achieved by inserting the bend-and-sweep compliant mechanism into the leading edge wing spar of the ornithopters.

  11. Coil End Parts Development Using BEND and Design for MQXF by LARP

    SciTech Connect

    Yu, Miao; Ambrosio, G.; Bermudez, S. Izquierdo; Bossert, R.; Ferracin, P.; Krave, S.

    2016-09-06

    End parts are critical components for saddle-shaped coils. They have a structural function where the cables are deformed in order to cross over the magnet aperture. Based on the previous design of the US LARP program for 90 mm aperture quadrupoles (TQ/LQ) and 120 mm aperture quadrupoles (HQ/LHQ) using BEND, the coil ends of the low-β quadruples (MQXF) for the HiLumi LHC upgrade were developed. This paper shows the design of the MQXF coil ends, the analysis of the coil ends during the coil fabrication, the autopsy analysis of the coil ends and the feedback to BEND parameters.

  12. Design of a multi-bend achromat lattice for 3 GeV synchrotron light source

    NASA Astrophysics Data System (ADS)

    Kim, Eun-San

    2016-03-01

    We present a lattice design for a low-emittance and high-brilliance 3 GeV synchrotron light source that has been widely investigated in the world. We show the design results for a MBA (Multi-Bend Achromat) lattice with an emittance of 1.3 nm and 282.4 m circumference. Each cell has 5 bending magnets that consist of outer two with bending angle of 4.5° and inner three with bending angle of 7°. The lattice is designed to be flexible and consists of 12 straight sections in which one straight section has a length of 5.9 m. We have studied the dynamic aperture in the lattice with machine errors. It is shown that the designed low-emittance lattice provides sufficient dynamic aperture after COD correction. We present the results of variations of emittance, energy spread and dynamic aperture due to in-vacuum undulators in the straight sections. We performed particle tracking after the beam injection to investigate the efficiency of the injection scheme. We show the designed results of an injection scheme that shows the space allocation in injection section and the particle motions of injected beam. Our designed lattice provides a good optimization in terms of the emittance and brilliance as a light source for 3 GeV energy and circumference of 28 m.

  13. Failure mechanisms in three and four point short beam bending tests of unidirectional glass/epoxy

    NASA Astrophysics Data System (ADS)

    Cui, W. C.; Wisnom, M. R.; Jones, M.

    1992-10-01

    Three and four point bending tests are compared both analytically and experimentally. In all the three point bending tests, damage was observed under the loading roller in addition to the interlaminar shear failure, while in the four point bending tests, only interlaminar shear failure was observed. Therefore, this four point bending test is valid for measuring the interlaminar shear strength. From the finite element analysis, it is found that the roller diameter is a critical parameter in determining the stress concentrations in short beam tests. In order to avoid damage under the roller and thus to make the short beam test a valid means for measuring the interlaminar shear strength, the appropriate roller diameters should be chosen. The damage under the loading roller in the three point bending test basically reduces the effective specimen thickness and thus this test underestimates the interlaminar shear strength. The interlaminar shear cracks in the short beam tests were found to be randomly distributed in a region between 30 percent and 70 percent through the thickness from the top surface. This is due to the non-linear shear response which means that the shear stress distribution is more uniform near the middle of the section. Also the maximum value of the shear stress is lower than the maximum value given by beam theory. A non-linear shear correction factor is suggested to account for this effect and for the glass/epoxy composite tested here, the actual interlaminar shear strength is only about 83 percent of the apparent value from classical beam theory.

  14. Static and Cyclic Load-Deflection Characteristics of NiTi Orthodontic Archwires Using Modified Bending Tests

    NASA Astrophysics Data System (ADS)

    Nili Ahmadabadi, Mahmoud; Shahhoseini, Tahereh; Habibi-Parsa, Mohamad; Haj-Fathalian, Maryam; Hoseinzadeh-Nik, Tahereh; Ghadirian, Hananeh

    2009-08-01

    Near-equiatomic nickel-titanium (nitinol) has the ability to return to a former shape when subjected to an appropriate thermomechanical procedure. One of the most successful applications of nitinol is orthodontic archwire. One of the suitable characteristics of these wires is superelasticity, a phenomenon that allows better-tolerated loading conditions during clinical therapy. Superelastic nitinol wires deliver clinically desired light continuous force enabling effective tooth movement with minimal damage for periodontal tissues. In this research, a special three-point bending fixture was invented and designed to determine the superelastic property in simulated clinical conditions, where the wire samples were held in the fixture similar to an oral cavity. In this experimental study, the load-deflection characteristics of superelastic NiTi commercial wires were studied through three-point bending test. The superelastic behavior was investigated by focusing on bending time, temperature, and number of cycles which affects the energy dissipating capacity. Experimental results show that the NiTi archwires are well suited for cyclic load-unload dental applications. Results show reduction in superelastic property for used archwires after long-time static bending.

  15. Parameters design of the dielectric elastomer spring-roll bending actuator (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Li, Jinrong; Liu, Liwu; Liu, Yanju; Leng, Jinsong

    2017-04-01

    Dielectric elastomers are novel soft smart material that could deform sustainably when subjected to external electric field. That makes dielectric elastomers promising materials for actuators. In this paper, a spring-roll actuator that would bend when a high voltage is applied was fabricated based on dielectric elastomer. Using such actuators as active parts, the flexible grippers and inchworm-inspired crawling robots were manufactured, which demonstrated some examples of applications in soft robotics. To guide the parameters design of dielectric elastomer based spring-roll bending actuators, the theoretical model of such actuators was established based on thermodynamic theories. The initial deformation and electrical induced bending angle of actuators were formulated. The failure of actuators was also analyzed considering some typical failure modes like electromechanical instability, electrical breakdown, loss of tension and maximum tolerant stretch. Thus the allowable region of actuators was determined. Then the bending angle-voltage relations and failure voltages of actuators with different parameters, including stretches of the dielectric elastomer film, number of active layers, and dimensions of spring, were investigated. The influences of each parameter on the actuator performances were discussed, providing meaningful guidance to the optical design of the spring-roll bending actuators.

  16. Elastic Moduli of Pyrolytic Boron Nitride Measured Using 3-Point Bending and Ultrasonic Testing

    NASA Technical Reports Server (NTRS)

    Kaforey, M. L.; Deeb, C. W.; Matthiesen, D. H.; Roth, D. J.

    1999-01-01

    Three-point bending and ultrasonic testing were performed on a flat plate of PBN. In the bending experiment, the deformation mechanism was believed to be shear between the pyrolytic layers, which yielded a shear modulus, c (sub 44), of 2.60 plus or minus .31 GPa. Calculations based on the longitudinal and shear wave velocity measurements yielded values of 0.341 plus or minus 0.006 for Poisson's ratio, 10.34 plus or minus .30 GPa for the elastic modulus (c (sub 33)), and 3.85 plus or minus 0.02 GPa for the shear modulus (c (sub 44)). Since free basal dislocations have been reported to affect the value of c (sub 44) found using ultrasonic methods, the value from the bending experiment was assumed to be the more accurate value.

  17. 16 CFR Figure 1 to Part 1512 - Bicycle Front Fork Cantilever Bending Test Rig

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Bicycle Front Fork Cantilever Bending Test Rig 1 Figure 1 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 1 Figure 1 to Part 1512—Bicycle...

  18. 16 CFR Figure 1 to Part 1512 - Bicycle Front Fork Cantilever Bending Test Rig

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Bicycle Front Fork Cantilever Bending Test Rig 1 Figure 1 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 1 Figure 1 to Part 1512—Bicycle...

  19. 16 CFR Figure 1 to Part 1512 - Bicycle Front Fork Cantilever Bending Test Rig

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Bicycle Front Fork Cantilever Bending Test Rig 1 Figure 1 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 1 Figure 1 to Part 1512—Bicycle...

  20. 16 CFR Figure 1 to Part 1512 - Bicycle Front Fork Cantilever Bending Test Rig

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Bicycle Front Fork Cantilever Bending Test Rig 1 Figure 1 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 1 Figure 1 to Part 1512—Bicycle...

  1. 16 CFR Figure 1 to Part 1512 - Bicycle Front Fork Cantilever Bending Test Rig

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Bicycle Front Fork Cantilever Bending Test Rig 1 Figure 1 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 1 Figure 1 to Part 1512—Bicycle...

  2. Historical perspective: William Adams, the forward bending test, and the spine of Gideon Algernon Mantell.

    PubMed

    Fairbank, Jeremy

    2004-09-01

    William Adams described the Forward Bending Test for scoliosis in 1865. His understanding of the nature of the rotational element of scoliosis was given by a postmortem he performed on an eminent surgeon and geologist, Gideon Mantell. The clinical history of Dr. Mantell is well documented.

  3. Design and delivery of the diamond double double bend achromat project

    SciTech Connect

    Kay, J. Hammond, N. P.; Thomson, A.

    2016-07-27

    A major project is underway at Diamond Light Source to remove one of the 24 Double Bend Achromat (DBA) Storage Ring cells and replace it with a Double Double Bend Achromat (DDBA). In this way a new Insertion Device (ID) straight can be created and so ID light can be produced and delivered to a beamline previously only capable of receiving Bending Magnet (BM) radiation. This project is in support of the micro-focus Protein Crystallography (MX) beamline VMX-m which is scheduled to take users towards the end of 2017. This paper describes the Engineering Design of the DDBA project in more detail and gives the current status of the project.

  4. A comparison of two reciprocating instruments using bending stress and cyclic fatigue tests.

    PubMed

    Scelza, Pantaleo; Harry, Davidowicz; Silva, Licinio Esmeraldo da; Barbosa, Igor Bastos; Scelza, Miriam Zaccaro

    2015-01-01

    The aim of this study was to comparatively evaluate the bending resistance at 45º, the static and dynamic cyclic fatigue life, and the fracture type of the WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) 25-08 and Reciproc (VDW, Munich, Germany) 25-08 instruments. A total of 60 nickel-titanium (NiTi) instruments (30 Reciproc and 30 WaveOne) from three different lots, each of which was 25 mm in length, were tested. The bending resistance was evaluated through the results of a cantilever-bending test conducted using a universal testing machine. Static and dynamic cyclic fatigue testing was conducted using a custom-made device. For the static and dynamic tests, a cast Ni-Cr-Mo-Ti alloy metal block with an artificial canal measuring 1.77 mm in diameter and 20.00 mm in total length was used. A scanning electron microscope was used to determine the type of fracture. Statistical analyses were performed on the results. The WaveOne instrument was less flexible than the Reciproc (p < 0.05). The Reciproc instrument showed better resistance in the static and dynamic cyclic fatigue tests (p < 0.05). The transverse cross-section and geometry of the instruments were important factors in their resistance to bending and cyclic fracture. Both of the instruments showed ductile-type fracture characteristics. It can be concluded that the Reciproc 25-08 instrument was more resistant to static and dynamic cyclic fatigue than the WaveOne 25-08 instrument, while the WaveOne 25-08 instrument was less flexible. Bending and resistance to cyclic fracture were influenced by the instruments' geometries and transverse cross-sections. Both of the instruments showed ductile-type fracture characteristics.

  5. Results of High Velocity Tests at Tampa Electric Company`s Big Bend 4 FGD System.

    SciTech Connect

    DeKraker, D.P.

    1997-10-15

    Test were conducted at the Big Bend Station to determine the feasibility of scrubbing gas from an additional boiler in the existing FGD system. Testing was accomplished by increasing the gas flow from the D absorber tower and measuring the performance of this module. Key performance aspects evaluated during the testing include mist eliminator performance, SO2 removal efficiency, oxidation of absorbed SO2, and limestone utilization.

  6. Design study of a low-emittance lattice with a five-bend achromat

    NASA Astrophysics Data System (ADS)

    Liu, Hao-Lin; Kim, Eun-San

    2016-04-01

    The multi-bend achromat (MBA) lattice, which can provide a small horizontal emittance in the subnanometer range, shows promise for future storage-ring-based light-source facilities. We present the linear and the nonlinear properties of an optical design and the results of its optimization. The MBA lattice is designed as a five-bend achromat, and an emittance of 0.270 nm rad is achieved. The energy and the circumference of the designed ring are 3 GeV and 499.3 m, respectively. We investigated an injection system with a single-pulsed sextupole magnet in the storage ring. We describe the space allocation in the injection section and the particle dynamics of the injected beam. The investigation shows that our design exhibits a very low emittance and a sufficient dynamic aperture, and provides a suitable injection scheme for a 3-GeV light source.

  7. Bending Tests of Circular Cylinders of Corrugated Aluminum-alloy Sheet

    NASA Technical Reports Server (NTRS)

    Buckwalter, John C; Reed, Warren D; Niles, Alfred S

    1937-01-01

    Bending tests were made of two circular cylinders of corrugated aluminum-alloy sheet. In each test failure occurred by bending of the corrugations in a plane normal to the skin. It was found, after analysis of the effect of short end bays, that the computed stress on the extreme fiber of a corrugated cylinder is in excess of that for a flat panel of the same basic pattern and panel length tested as a pin-ended column. It is concluded that this increased strength was due to the effects of curvature of the pitch line. It is also concluded from the tests that light bulkheads closely spaced strengthen corrugated cylinders very materially.

  8. Development of vehicle model test-bending of a simple structural surfaces model for automotive vehicle sedan

    NASA Astrophysics Data System (ADS)

    Nor, M. K. Mohd; Noordin, A.; Ruzali, M. F. S.; Hussen, M. H.; Mustapa@Othman, N.

    2017-04-01

    Simple Structural Surfaces (SSS) method is offered as a means of organizing the process for rationalizing the basic vehicle body structure load paths. The application of this simplified approach is highly beneficial in the development of modern passenger car structure design. In Malaysia, the SSS topic has been widely adopted and seems compulsory in various automotive programs related to automotive vehicle structures in many higher education institutions. However, there is no real physical model of SSS available to gain considerable insight and understanding into the function of each major subassembly in the whole vehicle structures. Based on this motivation, a real physical SSS of sedan model and the corresponding model vehicle tests of bending is proposed in this work. The proposed approach is relatively easy to understand as compared to Finite Element Method (FEM). The results prove that the proposed vehicle model test is useful to physically demonstrate the importance of providing continuous load path using the necessary structural components within the vehicle structures. It is clearly observed that the global bending stiffness reduce significantly when more panels are removed from the complete SSS model. The analysis shows the front parcel shelf is an important subassembly to sustain bending load.

  9. Single-mode optical fiber design with wide-band ultra low bending-loss for FTTH application.

    PubMed

    Watekar, Pramod R; Ju, Seongmin; Han, Won-Taek

    2008-01-21

    We propose a new design of a single-mode optical fiber (SMF) which exhibits ultra low bend sensitivity over a wide communication band (1.3 microm to 1.65 microm). A five-cladding fiber structure has been proposed to minimize the bending loss, estimated to be as low as 4.4x10(-10) dB/turn for the bend radius of 10 mm.

  10. Relating tensile, bending, and shear test data of asphalt binders to pavement performance

    SciTech Connect

    Chen, J.S.; Tsai, C.J.

    1998-12-01

    Eight different asphalt binders representing a wide range of applications for pavement construction were tested in uniaxial tension, bending, and shear stresses. Theoretical analyses were performed in this study to covert the data from the three engineering tests to stiffness moduli for predicting pavement performance. At low temperatures, high asphalt stiffness may induce pavement thermal cracking; thus, the allowable maximum stiffness was set at 1,000 MPa. At high temperatures, low asphalt stiffness may lead to pavement rutting (ruts in the road); master curves were constructed to rank the potential for rutting in the asphalts. All three viscoelastic functions were shown to be interchangeable within the linear viscoelastic region. When subjected to large deformation in the direct tension test, asphalt binders behaved nonlinear viscoelastic in which the data under bending, shear and tension modes were not comparable. The asphalts were, however, found toe exhibit linear viscoelasticity up to the failure point in the steady-state strain region.

  11. The use of experimental bending tests to more accurate numerical description of TBC damage process

    NASA Astrophysics Data System (ADS)

    Sadowski, T.; Golewski, P.

    2016-04-01

    Thermal barrier coatings (TBCs) have been extensively used in aircraft engines to protect critical engine parts such as blades and combustion chambers, which are exposed to high temperatures and corrosive environment. The blades of turbine engines are additionally exposed to high mechanical loads. These loads are created by the high rotational speed of the rotor (30 000 rot/min), causing the tensile and bending stresses. Therefore, experimental testing of coated samples is necessary in order to determine strength properties of TBCs. Beam samples with dimensions 50×10×2 mm were used in those studies. The TBC system consisted of 150 μm thick bond coat (NiCoCrAlY) and 300 μm thick top coat (YSZ) made by APS (air plasma spray) process. Samples were tested by three-point bending test with various loads. After bending tests, the samples were subjected to microscopic observation to determine the quantity of cracks and their depth. The above mentioned results were used to build numerical model and calibrate material data in Abaqus program. Brittle cracking damage model was applied for the TBC layer, which allows to remove elements after reaching criterion. Surface based cohesive behavior was used to model the delamination which may occur at the boundary between bond coat and top coat.

  12. Alternate Lattice Design for Advanced Photon Source Multi-Bend Achromat Upgrade

    SciTech Connect

    Sun, Yipeng; Borland, Michael

    2015-01-01

    A 67-pm hybrid-seven-bend achromat (H7BA) lattice is proposed for a futureAdvanced Photon Source (APS)multibend- achromat (MBA) upgrade. This lattice requires use of a swap-out (on-axis) injection scheme. Alternate lattice design work has also been performed to achieve better beam dynamics performance than the nominal APS MBA lattice, in order to allow beam accumulation. One of such alternate H7BA lattice designs, which still targets a very low emittance of 76 pm, is discussed in this paper. With these lattices, existing APS injector complex can be employed without the requirement of a very high charge operation. Studies show that an emittance below 76 pm can be achieved with the employment of reverse bends in an alternate lattice. We discuss the predicted performance and requirements for these lattices and compare them to the nominal lattice.

  13. MAGNET DESIGNS FOR THE MULTI-BEND ACHROMAT LATTICE AT THE ADVANCED PHOTON SOURCE

    SciTech Connect

    Jaski, M.; Liu, J.; Jain, A.; Spataro, C; Harding, D. J.; Kashikhin, V.; Lopes, M. L.

    2015-01-01

    The Advanced Photon Source (APS) is currently investigating replacing the existing two-bend 7 GeV lattice with a 6 GeV seven-bend achromat magnet lattice in order to achieve a low electron beam emittance [1]. This new lattice requires 1320 magnets, of which there are nine types. These include high strength quadrupoles (gradient up to ~97 T/m), sextupoles with second derivative of field up to ~7000 T/m2, longitudinal gradient dipoles with field ratio of up to 5, and transverse gradient dipoles with gradients of ~50 T/m and central field of ~0.6 T. These field requirements and the limited space available pose several design challenges. This paper presents a summary of magnet designs for the various magnet types developed through a collaboration of APS with FNAL and BNL.

  14. Utilization of the Bend Test for Determining Tensile Properties of a Brittle Material

    DTIC Science & Technology

    1975-08-01

    8217 5itCUmIV=CLAS5IFICATION OlP TMIS PAGC(Wb.. Date Uff-)- Block- No. 20 ABSTR.ACT A imited number of send as well as tension tests were performed...tends to predict-fracture stressesof -the -tnson s-cmn prxmtl %higher- -than- -those obtained in- the actual’ - tension tests. (Author) UNCLASSIFIEDp...SIIAP.D TENSION TEST SPECI.ENS ...... ................... .... 19 iI I. INTRODUCTION Interest in the bend test has gained considerable attention in

  15. Design of the optical structure of a LED light of airfield used on the taxiway centerline of bend

    NASA Astrophysics Data System (ADS)

    Ma, Xiaodan; Yang, Jianhong; Li, Lei

    2014-07-01

    Along with the continuous renewal of the light source, LED light source could have been used in the lights of airfield already. LED light source in the application will be more energy efficient. This paper designs the optical structure of the taxiway centerline light,which is used on the bend. Osram LT CPDP - KZ - 4 green LED has been chosen to be the light source.Optical components used in the structure, such as the prism, the lens, the scattering pieces, is designed on the basis of the optical design principles. The optical design principle include the edge-ray etendue conservation, conservation of energy and so on. Then, the structure is drawn and simulated. Completing these steps combines with software, such as ProE, Matlab and TracePro. To test the optical structure with Yuanfang GO-2000 distribution photometer. The test results meet the standards of the civil aviation administration's requirements. In order to further reduce energy consumption, and optimize the components on the premise of meeting the requirements of national standards. The paper reduces the input current from 900mA to 400mA by optimizing the components. The method of optimizing is combining the prism with scattering pieces and optimizing the lens surface. The optical structure of the taxiway centerline lights used on the bend after improving is more efficient and meet the requirements of national standards including chromaticity and light intensity.

  16. Refinements to the Mixed-Mode Bending Test for Delamination Toughness

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2000-01-01

    The mixed-mode bending (MMB) test for delamination toughness was first introduced in 1988. This simple test is a combination of the standard Mode I (opening) test and a Mode II (sliding) test. This MMB test has become widely used in the United States and around the world for mixed-mode toughness measurements. Because of the widespread use of this test method, it is being considered for standardization by ASTM Committee D30. This paper discusses several improvements to the original test method. The improvements to the MMB test procedure include an improved method for calculating toughness from the measured test quantities, a more accurate way of setting the mixed-mode ratio to be tested, and the inclusion of a new alignment criterion for improved consistency in measured values.

  17. A Criterion to Control Nonlinear Error in the Mixed-Mode Bending Test

    NASA Technical Reports Server (NTRS)

    Reeder, James R.

    2002-01-01

    The mixed-mode bending test ha: been widely used to measure delamination toughness and was recently standardized by ASTM as Standard Test Method D6671-01. This simple test is a combination of the standard Mode I (opening) test and a Mode II (sliding) test. This test uses a unidirectional composite test specimen with an artificial delamination subjected to bending loads to characterize when a delamination will extend. When the displacements become large, the linear theory used to analyze the results of the test yields errors in the calcu1ated toughness values. The current standard places no limit on the specimen loading and therefore test data can be created using the standard that are significantly in error. A method of limiting the error that can be incurred in the calculated toughness values is needed. In this paper, nonlinear models of the MMB test are refined. One of the nonlinear models is then used to develop a simple criterion for prescribing conditions where thc nonlinear error will remain below 5%.

  18. Experimental investigation of fatigue behavior of carbon fiber composites using fully-reversed four-point bending test

    NASA Astrophysics Data System (ADS)

    Amiri, Ali

    Carbon fiber reinforced polymers (CFRP) have become an increasingly notable material for use in structural engineering applications. Some of their advantages include high strength-to-weight ratio, high stiffness-to-weight ratio, and good moldability. Prediction of the fatigue life of composite laminates has been the subject of various studies due to the cyclic loading experienced in many applications. Both theoretical studies and experimental tests have been performed to estimate the endurance limit and fatigue life of composite plates. One of the main methods to predict fatigue life is the four-point bending test. In most previous works, the tests have been done in one direction (load ratio, R, > 0). In the current work, we have designed and manufactured a special fixture to perform a fully reversed bending test (R = -1). Static four-point bending tests were carried out on three (0°/90°)15 and (± 45°)15 samples to measure the mechanical properties of CFRP. Testing was displacement-controlled at the rate of 10 mm/min until failure. In (0°/90°)15 samples, all failed by cracking/buckling on the compressive side of the sample. While in (± 45°)15 all three tests, no visual fracture or failure of the samples was observed. 3.4 times higher stresses were reached during four-point static bending test of (0° /90°)15 samples compared to (± 45°)15. Same trend was seen in literature for similar tests. Four-point bending fatigue tests were carried out on (0° /90°)15 sample with stress ratio, R = -1 and frequency of 5 Hz. Applied maximum stresses were approximately 45%, 56%, 67%, 72% and 76% of the measured yield stress for (0° /90°)15 samples. There was visible cracking through the thickness of the samples. The expected downward trend in fatigue life with increasing maximum applied stress was observed in S-N curves of samples. There appears to be a threshold for ‘infinite’ life, defined as 1.7 million cycles in the current work, at a maximum stress of about

  19. Determination of dynamic fracture-initiation toughness using a novel impact bend test procedure

    SciTech Connect

    Yokoyama, T. . Faculty of Engineering Okayama Univ. of Science . Dept. of Mechanical Engineering)

    1993-11-01

    A novel impact bend test procedure is described for determining the dynamic fracture-initiation toughness, K[sub Id], at a loading rate (stress intensity factor rate), K[sub I], of the order of 10[sup 6] MPa [radical]m/s. A special arrangement of the split Hopkinson pressure bar is adopted to measure accurately dynamic loads applied to a fatigue-precracked bend specimen. The dynamic stress intensity factor history for the bend specimen is evaluated by means of a dynamic finite element technique. The onset of crack initiation is detected using a string gage attached on the side of the specimen near a crack tip. The value of K[sub Id] is determined from the critical dynamic stress intensity factor at crack initiation. A series of dynamic fracture tests is carried out on a 7075-T6 aluminum alloy, a Ti-6246 alloy and an AISI 4340 steel. The K[sub Id] values obtained for the three structural materials are compared with the corresponding values obtained under quasi-static loading conditions.

  20. Design study of the bending sections between harmonic cascade FEL stages

    SciTech Connect

    Wan, Weishi; Corlett, John; Fawley, William; Zholents, A.

    2004-06-30

    The present design of LUX (linac based ultra-fast X-ray facility) includes a harmonic cascade FEL chain to generate coherent EUV and soft X-ray radiation. Four cascade stages, each consisting of two undulators acting as a modulator and a radiator, respectively, are envisioned to produce photons of approximate wavelengths 48 nm, 12 nm, 4 nm and 1 nm. Bending sections may be placed between the modulator and the radiator of each stage to adjust and maintain bunching of the electrons, to separate, in space, photons of different wavelengths and to optimize the use of real estate. In this note, the conceptual design of such a bending section, which may be used at all four stages, is presented. Preliminary tracking results show that it is possible to maintain bunch structure of nm length scale in the presence of errors, provided that there is adequate orbit correction and there are 2 families of trim quads and trim skew quads, respectively, in each bending section.

  1. A benchmark bending test of a thick specimen, Part 1: Experiments

    NASA Astrophysics Data System (ADS)

    Finney, J. M.; Kowal, E.

    1993-06-01

    An experiment has been undertaken to provide benchmark data for validating methods of calculating the plastic behavior of metals. In this experiment a 30 mm square-test-section specimen of 7050-T7451 aluminum alloy has been loaded in four-point bending, and the surface distortions of all four faces have been measured with the aid of a square grid pattern imposed on the surfaces before deformation. This part of the report describes the experimental details and gives the results of the material property tests, thus, providing sufficient information for the prediction of surface displacements. Part II of the report gives the measured displacements with which predictions may be compared.

  2. Interfacial strength analyses of Al/Mg compounds using bending tests

    NASA Astrophysics Data System (ADS)

    Lehmann, T.; Kirbach, C.; Müller, J.; Stockmann, M.; Ihlemann, J.

    2017-03-01

    In the Collaborative Research Center 692, subproject B3 Al/Mg compounds are investigated. The hydrostatic co-extruded compounds presented in this paper were further manufactured by the forging process Rising. To continue the first investigations of Rising specimens regarding interface strength, a bending test developed in a previous project period was used. The specific load case and the bending specimen geometry considers the requirements concerning the special geometry of the Rising specimen. Based on experimentally determined failure forces (maximum forces), the stress state for the investigation of the interface strength was calculated by means of the elementary bending theory extended with a numerical determined correction factor. The numerical analyses were based on a parametric FE model of the load case. Crack initiation was caused by the maximum interlaminar interfacial tension stress. In the demonstrated investigations co-extruded compounds with different ratio of core material (Mg) in the transversal cross sectional area of the initial billet were analyzed. A particular feature of the investigations is the interfacial strength analysis of a subset of Rising specimens in different areas of the transversal cross section. This was enabled by using compounds with larger sleeve thickness due to a lower Mg ratio. Thus, in this case a more extensive characterization could be performed. The results show higher strength values for Rising specimens with the largest sleeve thickness compared to the other investigated configurations.

  3. Novel bending-resistant design of two-layer low-index trench fiber with parabolic-profile core.

    PubMed

    Sun, Jiang; Kang, Zexin; Wang, Jing; Liu, Chao; Jian, Shuisheng

    2014-07-28

    A novel design, two-layer low-index trench fiber with parabolic-profile core, is proposed and investigated numerically in this paper. Based on scalar FD-BPM algorithm, the excellent performance over other types of structures and great potential in mode area enlargement are demonstrated. The effective mode area of our design (D = 100μm) is approximately 890 μm2. Both the high order mode (HOM) suppression and bending resistance of our design are better than that of Multi-Trench Fiber (MTF). The mode loss ratio and effective mode area are independent on the bending radius. Due to the circular symmetry of our proposed configuration design, the bending property is not varied with the changing of bending directions.

  4. Design and Fabrication of the Superconducting Horizontal Bend Magnet for the Super High Momentum Spectrometer at Jefferson Lab

    SciTech Connect

    Chouhan, Shailendra S.; DeKamp, Jon; Burkhart, E. E,; Bierwagen, J.; Song, H.; Zeller, Albert F.; Brindza, Paul D.; Lassiter, Steven R.; Fowler, Michael J.; Sun, Qiuli

    2015-06-01

    A collaboration exists between NSCL and JLab to design and build JLab's Super High Momentum Spectrometer (SHMS) horizontal bend magnet that allows the bending of the 12 GeV/c particles horizontally by 3° to allow SHMS to reach angles as low as 5.5°. Two full size coils have been wound and are cold tested for both magnetic and structural properties. Each coil is built from 90 layers of single-turn SSC outer conductor cable. An initial test coil with one third the turns was fabricated to demonstrate that the unique saddle shape with fully contoured ends could be wound with Rutherford superconducting cable. Learned lessons during the trial winding were integrated into the two complete full-scale coils that are now installed in the helium vessel. The fabrication of the iron yoke, cold mass, and thermal shield is complete, and assembly of the vacuum vessel is in progress. This paper presents the process and progress along with the modified magnet design to reduce the fringe field in the primary beam region and also includes the impact of the changes on coil forces and coil restraint system.

  5. Effect of fluoride mouth rinses on various orthodontic archwire alloys tested by modified bending test: an in vitro study.

    PubMed

    Srivastava, Kamna; Chandra, Pavan Kumar; Kamat, Nandini

    2012-01-01

    Fluorides can cause corrosion and degradation in mechanical properties of commonly used archwires by forming hydrofluoric acid HF and causing disruption of protective titanium oxide layer. Hence, the aim of this study was to assess the change in load deflection characteristics of Ni-Ti, Cu Ni-Ti, S.S, and β-Ti wires on immersing in fluoride mouth rinses of two types- Phosflur and neutral NaF mouth rinse utilizing a modified bending test and comparing it to control. Round preformed wires were immersed in 10 ml of control and test solution (Phosflur and S-Flo mouth rinse) for 1.5 hours and incubated at 37°C. Modified bending test was carried out to evaluate load-deflection characteristics of different wires using Instron. Analysis of variance (ANOVA) was applied to determine if statistically significant difference exist among the mean load values obtained at various deflections in control and test solutions. There was no statistically significant reduction in load deflection characteristics of Ni-Ti, copper Ni-Ti, β-Ti, and S.S wires on immersing in Phosflur mouth rinse and neutral sodium fluoride mouth rinses as compared to control at 2.5 and 1 mm of deflection in unloading phase. Phosflur and a neutral sodium fluoride mouth rinse did not affect the mechanical bending properties of Ni-Ti, copper Ni-Ti, B-Ti, and SS wires in in vitro conditions.

  6. Bending and pressurisation test of the human aortic arch: experiments, modelling and simulation of a patient-specific case.

    PubMed

    García-Herrera, Claudio M; Celentano, Diego J; Cruchaga, Marcela A

    2013-01-01

    This work presents experiments, modelling and simulation aimed at describing the mechanical behaviour of the human aortic arch during the bending and pressurisation test. The main motivation is to describe the material response of this artery when it is subjected to large quasi-static deformations in three different stages: bending, axial stretching and internal pressurisation. The sample corresponds to a young artery without cardiovascular pathologies. The pressure levels are within the normal and hypertension physiological ranges. The two principal findings of this work are firstly, the material characterisation performed via tensile test measurements that serve to derive the material parameters of a hyperelastic isotropic constitutive model and, secondly, the assessment of these material parameters in the simulation of the bending and pressurisation test. Overall, the reported material characterisation was found to provide a realistic description of the mechanical behaviour of the aortic arch under severe complex loading conditions considered in the bending and pressurisation test.

  7. Fabrication and testing of novel blood separation devices based on microchannel bend structures

    NASA Astrophysics Data System (ADS)

    Blattert, C.; Jurischka, R.; Schoth, A.; Kerth, P.; Menz, W.

    2005-02-01

    Most clinical chemistry tests are performed on cell-free serum or plasma. Therefore micro assay devices for blood tests require integrated on-chip microfluidics for separation of plasma or serum from blood. Polymers are ideally suited for these applications due to their material properties and their applicability for high volume production. These requirements are achieved by a new on-chip blood separation technique based on microchannel bend structures and a rapid processing technology for micro assay devices using injection molding or hot embossing. Different prototype polymer chips with channel dimensions down to 20 μm and aspect ratios of 4 have been fabricated by injection molding and hot embossing. The inserts for the molding tools were fabricated by an UV-LIGA technology. The separation efficiency of these chips has been tested with human blood samples. The results show different separation efficiencies up to 100 % for blood cells and plasma depending on microchannel geometry as well as cell concentration. As compared to present microfluidic devices for the separation of blood cells like filters, membranes or filtration by diffusion the microchannel bend is an integrated on-chip blood separation method. It combines the advantages of rapid separation times and a simple geometry that leads to cost-effective high volume production using injection molding.

  8. Design of triangular core LMA-PCF with low-bending loss and low non-linearity for laser application

    NASA Astrophysics Data System (ADS)

    Kabir, Sumaiya; Khandokar, Md. Rezwanul Haque; Khan, Muhammad Abdul Goffar

    2016-07-01

    In this paper we characterize the design of a simple large-mode area photonic crystal fiber (LMA-PCF) with low bending loss and low non-linearity. The finite element method (FEM) with perfectly matched boundary layer (PML) is used to investigate the guiding properties. According to simulation the characterized four ring fluorine doped triangular core LMA-PCF achieves 1500 μm2 effective mode area with a low bending loss of 10-5dB/km at the wavelength of 1.064 μm and at a bending radius of 40 cm which is suitable for high power fiber laser.

  9. Design optimization of wide-band Tonpilz piezoelectric transducer with a bending piezoelectric disk on the radiation surface.

    PubMed

    Saijyou, Kenji; Okuyama, Tomonao

    2010-05-01

    Wide-band Tonpilz piezoelectric transducer with a bending piezoelectric disk on the radiation surface has been proposed to improve sonar detection performance in shallow water. This transducer is driven by utilizing two vibration modes, i.e., longitudinal and bending. Consequently, to achieve a wide-band signal transmission by this transducer, the phase difference between signals, which drive the ring-stack and the bending-disk piezoelectric resonators has to be optimized. In this paper, optimization approach of this phase difference in the design process is proposed. The effectiveness of this approach was confirmed by water-pool experiments.

  10. Bending properties of a macroalga: Adaptation of Peirce's cantilever test for in situ measurements of Laminaria digitata (Laminariaceae).

    PubMed

    Henry, Pierre-Yves T

    2014-06-01

    • Premise of the study: The mechanical properties of a plant are key variables governing the interaction between the plant and its environment. Thus, measuring variables such as the flexural rigidity (bending) of a plant element is necessary to understand and predict the plant-flow interaction. However, plant elements such as macrophyte blades can be relatively thin and flexible, thus difficult to characterize. Different adaptations of the classical 3-point bending tests can also affect the interpretation of the flexural rigidity of an element. A simple, robust, method is newly applied to a biomaterial and validated here as an alternative to measure flexural rigidity of thin, flexible plant elements.• Methods: Based on a bending test procedure developed for the textile industry, an apparatus for in-situ measurements was developed and compared with other normalized methods, then used in a field test on the blade of a marine macroalga (Laminaria digitata) to assess its suitability to measure the bending modulus of a biomaterial.• Key results: Results of the presented method on selected surrogate materials agree with a normalized cantilever method (ISO 9073-7:1998) and 3-point bending test (ISO 178:2010). Values determined for the bending moduli for blades of L. digitaria were in the typical range for algal material. The range of validity of the method is discussed.• Conclusion: By validating this method with existing norms, this study suggests a better approach to measure bending properties of different biomaterials in the field compared with more traditional bending tests and opens new possibilities. © 2014 Botanical Society of America, Inc.

  11. Design of pseudo-symmetric high bit rate, bend insensitive optical fiber applicable for high speed FTTH

    NASA Astrophysics Data System (ADS)

    Makouei, Somayeh; Koozekanani, Z. D.

    2014-12-01

    In this paper, with sophisticated modification on modal-field distribution and introducing new design procedure, the single-mode fiber with ultra-low bending-loss and pseudo-symmetric high bit-rate of uplink and downlink, appropriate for fiber-to-the-home (FTTH) operation is presented. The bending-loss reduction and dispersion management are done by the means of Genetic Algorithm. The remarkable feature of this methodology is designing a bend-insensitive fiber without reduction of core radius and MFD. Simulation results show bending loss of 1.27×10-2 dB/turn at 1.55 μm for 5 mm curvature radius. The MFD and Aeff are 9.03 μm and 59.11 μm2. Moreover, the upstream and downstream bit-rates are approximately 2.38 Gbit/s-km and 3.05 Gbit/s-km.

  12. A biomechanical analysis of plate fixation using unicortical and bicortical screws in transverse metacarpal fracture models subjected to 4-point bending and dynamical bending test.

    PubMed

    Liodaki, Eirini; Wendlandt, Robert; Waizner, Klaus; Schopp, Brigitte E; Mailänder, Peter; Stang, Felix

    2017-07-01

    In the published literature there are controversial data to the biomechanical stability of monocortical comparing to the bicortical fixation of metacarpal fractures. The aim of this study was to compare the biomechanical stability of monocortical and bicortical locking osteosynthesis in quasi-static and dynamic 4-point bending tests of composite third metacarpal bone (4th Gen third metacarpal, Sawbones, Malmö, Sweden) fixed with 7-hole locking plate (XXS System, Biotech-Ortho, Wright, Memphis, TN). The tests to determine quasi-static yield and bending strength as well as fatigue strength were conducted in 4 groups of 10 samples after creating standardized mid-shaft transverse osteotomies using a diamont belt grinder (0.3 mm saw blade). The force applied was the dorsal apex loading, similar to the forces applied to metacarpals during normal finger flexion and extension.In the quasi-static testing, no plate breakage was observed in each group. All metacarpals broke at their thinnest part. The average bending strength of the bicortical samples (10.54 ± 0.998 Nm) was significantly higher comparing to the monocortical samples (8.57 ± 0.894 Nm) (P < .001).In the dynamic loading test, all constructs (8 monocortical samples and 7 bicortical) that failed broke at the osteotomy site and the average fatigue strength did not differ in both groups.Consequently, a unicortical plating method may provide adequate strength and stability to metacarpal fractures based on the results of the cyclical loading representative of in vivo loading.

  13. A biomechanical analysis of plate fixation using unicortical and bicortical screws in transverse metacarpal fracture models subjected to 4-point bending and dynamical bending test

    PubMed Central

    Liodaki, Eirini; Wendlandt, Robert; Waizner, Klaus; Schopp, Brigitte E.; Mailänder, Peter; Stang, Felix

    2017-01-01

    Abstract In the published literature there are controversial data to the biomechanical stability of monocortical comparing to the bicortical fixation of metacarpal fractures. The aim of this study was to compare the biomechanical stability of monocortical and bicortical locking osteosynthesis in quasi-static and dynamic 4-point bending tests of composite third metacarpal bone (4th Gen third metacarpal, Sawbones, Malmö, Sweden) fixed with 7-hole locking plate (XXS System, Biotech-Ortho, Wright, Memphis, TN). The tests to determine quasi-static yield and bending strength as well as fatigue strength were conducted in 4 groups of 10 samples after creating standardized mid-shaft transverse osteotomies using a diamont belt grinder (0.3 mm saw blade). The force applied was the dorsal apex loading, similar to the forces applied to metacarpals during normal finger flexion and extension. In the quasi-static testing, no plate breakage was observed in each group. All metacarpals broke at their thinnest part. The average bending strength of the bicortical samples (10.54 ± 0.998 Nm) was significantly higher comparing to the monocortical samples (8.57 ± 0.894 Nm) (P < .001). In the dynamic loading test, all constructs (8 monocortical samples and 7 bicortical) that failed broke at the osteotomy site and the average fatigue strength did not differ in both groups. Consequently, a unicortical plating method may provide adequate strength and stability to metacarpal fractures based on the results of the cyclical loading representative of in vivo loading. PMID:28682860

  14. Simplified analytical model and balanced design approach for light-weight wood-based structural panel in bending

    Treesearch

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2016-01-01

    This paper presents a simplified analytical model and balanced design approach for modeling lightweight wood-based structural panels in bending. Because many design parameters are required to input for the model of finite element analysis (FEA) during the preliminary design process and optimization, the equivalent method was developed to analyze the mechanical...

  15. The biomechanics of human ribs: material and structural properties from dynamic tension and bending tests.

    PubMed

    Kemper, Andrew R; McNally, Craig; Pullins, Clayton A; Freeman, Laura J; Duma, Stefan M; Rouhana, Stephen M

    2007-10-01

    The purpose of this study was to quantify both the tensile material properties and structural response of human ribs in order to determine which variables contribute to regional variation in the strength of human ribs. This was done by performing 94 matched tests on human rib specimens; 46 tension coupon tests, 48 three-point bending tests. Contralateral matched specimens were dissected from anterior and lateral regions of ribs 4 through 7 of six male fresh frozen post mortem human subjects ranging from 42 to 81 years of age. Tension coupons were taken from one side of the thorax, while three-point bending specimens were taken from the opposite side as the tension coupons at corresponding anatomical locations. The results of the tension coupon testing showed that there were no significant differences with respect to region or rib level: ultimate stress (p=0.90; p=0.53), ultimate strain (p=0.49; p=0.86), or modulus (p=0.72; p=0.81). In contrast, lateral three-point bending specimens were found to have a significantly higher peak bending moment (p<0.01), peak strain (p=0.03), modulus (p=0.05), and stiffness (p<0.01) than anterior specimens. The lateral three-point bending specimens also had a significantly larger area moment of inertia (p<0.01), larger distance to the neutral axis (p<0.01), smaller ratio of distance to the neutral axis to area moment of inertia (p<0.01), larger cortical bone area (p<0.01), and larger radius of gyration (p<0.01) than the anterior specimens. In addition, the peak moment (Ant p=0.20; Lat p=0.02), peak strain (Ant p=0.05; Lat p=0.15), and stiffness (Ant p<0.01; Lat p<0.01) were found to vary significantly with respect to rib level. Similar to anatomical region, the changes in the structural response with respect to rib level were also accompanied by significant changes in geometry. For anterior specimens, distance to the neutral axis (p<0.01), ratio of the distance to the neutral axis to area moment of inertia (p=0.02) and radius of

  16. Surface effects in various bending-based test methods for measuring the elastic property of nanowires.

    PubMed

    Zheng, Xiu-Peng; Cao, Yan-Ping; Li, Bo; Feng, Xi-Qiao; Wang, Gang-Feng

    2010-05-21

    The size-dependent elastic property of nanowires induced by the surface effect is investigated by using the core-shell model. The overall effective elastic moduli of nanowires with regular polygonal cross-sections are unified into a simple and explicit relation. It is found that the effect of surface elasticity on the elastic moduli can be well characterized by two dimensionless material and geometric parameters with clear physical meaning. Finite element simulations demonstrate that the derived theoretical relation is applicable for all the vibration, bending, and buckling test methods for measuring the mechanical properties of nanowires. The analytical result is also validated by comparing it with relevant experimental measurements. This study is helpful not only for interpreting various phenomena associated with size-dependent mechanical properties of nanowires but also for developing and evaluating test techniques for material characterization at the nanoscale.

  17. A benchmark bending test of a thick specimen. Part 2: Surface displacement measurements

    NASA Astrophysics Data System (ADS)

    Finney, J. M.; Kowal, E.

    1993-06-01

    An experiment has been undertaken to provide benchmark data for validating methods of calculating the plastic behavior of metals. In this experiment, a 30 mm square-test-section specimen of 7050-T7451 aluminum alloy has been loaded in four-point bending, and the surface distortions of all four faces have been measured with the aid of a square grid pattern imposed on the surfaces before deformation. Part 1 of the report describes the experimental details and gives the results of the material property tests, thus, providing sufficient information for the prediction of surface displacements. This part of the report gives the displacements measured and describes the various manipulation and averaging procedures used with the data to put them in a form suitable for comparison with predictions.

  18. A photoelastic investigation of asymmetric four point bend shear test for composite materials

    NASA Technical Reports Server (NTRS)

    Prabhakaran, R.; Sawyer, W.

    1986-01-01

    The shear stress fringe value of orthotropic birefringent model materials is presently used in an asymmetric four-point bend test that employs a notched specimen and is a modification of the Iosipescu test (1967). While in the case of a unidirectionally reinforced glass-polyester model material, shear stress fringe values obtained from 90- and 120-deg (sharp and radiused) notches are reasonably close to the values obtained for an off-axis tensile specimen, no conclusions can be drawn on the influence of the notch parameters, due to the peculiarities of the photoelastic response of the inhomogeneous orthotropic model material. The failure modes nevertheless indicate that a notch radius, and the 120-deg notch angle, reduce the stress concentration. Comparisons are made with finite element results.

  19. Accelerated test design

    NASA Technical Reports Server (NTRS)

    Mcdermott, P. P.

    1980-01-01

    The design of an accelerated life test program for electric batteries is discussed. A number of observations and suggestions on the procedures and objectives for conducting an accelerated life test program are presented. Equations based on nonlinear regression analysis for predicting the accelerated life test parameters are discussed.

  20. Development of four-point bending fatigue test method using continuously hydrogen-charging pipe specimen

    NASA Astrophysics Data System (ADS)

    Yoshimoto, T.; Matsuo, T.

    2017-05-01

    To evaluate hydrogen embrittlement, the following two types of testing method are available: (i) testing in high-pressure hydrogen gas environment and (ii) testing in ambient air using hydrogen precharged specimen. Testing in high-pressure hydrogen gas environment is technically difficult and expensive because high-pressure gas equipments, such as high-pressure vessel and pipe, have to be installed in the laboratory. On the other hand, in the case of precharging method, outgassing of hydrogen from the specimen occurs during the test. Therefore, hydrogen embrittlement can hardly be evaluated properly, especially, in long-term testing such as high cycle fatigue test at low frequency. In this study, to effectively evaluate the hydrogen embrittlement in fatigue, an experimental method, which was the four-point bending fatigue test system with a mechanism of internal circulation of hydrogen-charging solution in a pipe specimen, was developed. By using this method, the fatigue crack growth properties in the presence of hydrogen were investigated at frequencies of 0.05 Hz and 1 Hz.

  1. Conceptual Design of Front Ends for the Advanced Photon Source Multi-bend Achromats Upgrade

    SciTech Connect

    Jaski, Y.; Westferro, F.; Lee, S. H.; Yang, B.; Abliz, M.; Ramanathan, M.

    2016-07-27

    The proposed Advanced Photon Source (APS) upgrade from a double-bend achromats (DBA) to multi-bend achromats (MBA) lattice with ring energy change from 7 GeV to 6 GeV and beam current from 100 mA to 200 mA poses new challenges for front ends. All front ends must be upgraded to fulfill the following requirements: 1) handle the high heat load from two insertion devices in either inline or canted configuration, 2) include a clearing magnet in the front end to deflect and dump any electrons in case the electrons escape from the storage ring during swap-out injection with the safety shutters open, 3) incorporate the next generation x-ray beam position monitors (XBPMs) into the front end to meet the new stringent beam stability requirements. This paper presents the evaluation of the existing APS front ends and standardizes the insertion device (ID) front ends into two types: one for the single beam and one for the canted beams. The conceptual design of high heat load front end (HHLFE) and canted undulator front end (CUFE) for APS MBA upgrade is presented.

  2. Flexural strengths of conventional and nanofilled fiber-reinforced composites: a three-point bending test.

    PubMed

    Sfondrini, Maria Francesca; Massironi, Sarah; Pieraccini, Giulia; Scribante, Andrea; Vallittu, Pekka K; Lassila, Lippo V; Gandini, Paola

    2014-02-01

    The purpose of this study was to evaluate the effect of the introduction of nanofillers on the mechanical properties of fiber-reinforced composites (FRCs) for stabilization and conservative treatment of multiple traumatized anterior teeth. In particular, the aim of the research was to point out the force levels of two sizes (diameters 0.6 and 0.9 mm) of both conventional and nanofilled FRCs. Eighty FRCs samples were divided into eight groups, each consisting of 10 specimens. Conventional (groups 1, 2, 3, and 4) and nanofilled (groups 5, 6, 7, and 8) FRC samples were evaluated. Each FRC was tested in two diameters (0.6 and 0.9 mm) and under two deflections (1 and 2 mm). Each sample was polymerized with the same halogen curing unit and then evaluated with a 3-point bending test on a universal testing machine after 48 h of dry storage. Nanofilled FRCs showed significantly higher load values than conventional FRCs. Moreover, 0.9-mm-diameter FRCs showed significantly higher load value than 0.6-mm-diameter FRCs. Specimens tested at 2-mm deflection showed significantly higher load values than those tested at 1-mm deflection. Nanofilled FRCs showed significantly higher load values than conventional FRCs. Higher flexural strength values were recorded with 1-mm deflection for both FRC tested. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Computer Designed Instruction & Testing.

    ERIC Educational Resources Information Center

    New Mexico State Univ., Las Cruces.

    Research findings on computer designed instruction and testing at the college level are discussed in 13 papers from the first Regional Conference on University Teaching at New Mexico State University. Titles and authors are as follows: "Don't Bother Me with Instructional Design, I'm Busy Programming! Suggestions for More Effective Educational…

  4. Computer Designed Instruction & Testing.

    ERIC Educational Resources Information Center

    New Mexico State Univ., Las Cruces.

    Research findings on computer designed instruction and testing at the college level are discussed in 13 papers from the first Regional Conference on University Teaching at New Mexico State University. Titles and authors are as follows: "Don't Bother Me with Instructional Design, I'm Busy Programming! Suggestions for More Effective Educational…

  5. Progress Letter Report on Bending Fatigue Test System Development for Spent Nuclear Fuel Vibration Integrity Study (Out-of-cell fatigue testing development - Task 2.4)

    SciTech Connect

    Wang, Jy-An John; Wang, Hong; Cox, Thomas S; Baldwin, Charles A; Bevard, Bruce Balkcom

    2013-08-01

    Vibration integrity of high burn-up spent nuclear fuel in transportation remains to be a critical component of US nuclear waste management system. The structural evaluation of package for spent fuel transportation eventually will need to see if the content or spent fuel is in a subcritical condition. However, a system for testing and characterizing such spent fuel is still lacking mainly due to the complication involved with dealing radioactive specimens in a hot cell environment. Apparently, the current state-of-the-art in spent fuel research and development is quite far away from the delivery of reliable mechanical property data for the assessment of spent fuels in the transport package evaluation. Under the sponsorship of US NRC, ORNL has taken the challenge in developing a robust testing system for spent fuel in hot cell. An extensive literature survey was carried out and unique requirements of such testing system were identified. The U-frame setup has come to the top among various designs examined for reverse bending fatigue test of spent fuel rod. The U-frame has many features that deserve mentioned here: Easy to install spent fuel rod in test; Less linkages than in conventional bending test setup such as three-point or four-point bending; Target the failure mode relevant to the fracture of spent fuel rod in transportation by focusing on pure bending; The continuous calibrations and modifications resulted in the third generation (3G) U-frame testing setup. Rigid arms are split along the LBB axis at rod sample ends. For each arm, this results in a large arm body and an end piece. Mating halves of bushings were modified into two V-shaped surfaces on which linear roller bearings (LRB) are embedded. The rod specimen is installed into the test fixture through opening and closing slide end-pieces. The 3G apparently has addressed major issues of setup identified in the previous stage and been proven to be eligible to be further pursued in this project. On the other

  6. Semicircular bend testing with split Hopkinson pressure bar for measuring dynamic tensile strength of brittle solids

    NASA Astrophysics Data System (ADS)

    Dai, F.; Xia, K.; Luo, S. N.

    2008-12-01

    We propose and validate an indirect tensile testing method to measure the dynamic tensile strength of rocks and other brittle solids: semicircular bend (SCB) testing with a modified split Hopkinson pressure bar (SHPB) system. A strain gauge is mounted near the failure spot on the specimen to determine the rupture time. The momentum trap technique is utilized to ensure single pulse loading for postmortem examination. Tests without and with pulse shaping are conducted on rock specimens. The evolution of tensile stress at the failure spot is determined via dynamic and quasistatic finite element analyses with the dynamic loads measured from SHPB as inputs. Given properly shaped incident pulse, far-field dynamic force balance is achieved and the peak of the loading matches in time with the rupture onset of the specimen. In addition, the dynamic tensile stress history at the failure spot obtained from the full dynamic finite element analysis agrees with the quasistatic analysis. The opposite occurs for the test without pulse shaping. These results demonstrate that when the far-field dynamic force balance is satisfied, the inertial effects associated with stress wave loading are minimized and thus one can apply the simple quasistatic analysis to obtain the tensile strength in the SCB-SHPB testing. This method provides a useful and cost effective way to measure indirectly the dynamic tensile strength of rocks and other brittle materials.

  7. SLOW BEND-TENSION TEST CORRELATIONS OF SHORT BEAMS WITH SPECIAL REFERENCE TO THE CHARPY-TYPE SPECIMEN,

    DTIC Science & Technology

    longitudinal compressive stress of the unnotched Charpy specimen correlated well with the uniaxial tension test yield stress data. Also, the yield loads...unnotched Charpy yield-load data. Finally, it is shown that it is possible to calculate from uniaxial tension test data the maximum bending load of an

  8. Numerical Modeling for Hole-Edge Cracking of Advanced High-Strength Steels (AHSS) Components in the Static Bend Test

    NASA Astrophysics Data System (ADS)

    Kim, Hyunok; Mohr, William; Yang, Yu-Ping; Zelenak, Paul; Kimchi, Menachem

    2011-08-01

    Numerical modeling of local formability, such as hole-edge cracking and shear fracture in bending of AHSS, is one of the challenging issues for simulation engineers for prediction and evaluation of stamping and crash performance of materials. This is because continuum-mechanics-based finite element method (FEM) modeling requires additional input data, "failure criteria" to predict the local formability limit of materials, in addition to the material flow stress data input for simulation. This paper presents a numerical modeling approach for predicting hole-edge failures during static bend tests of AHSS structures. A local-strain-based failure criterion and a stress-triaxiality-based failure criterion were developed and implemented in LS-DYNA simulation code to predict hole-edge failures in component bend tests. The holes were prepared using two different methods: mechanical punching and water-jet cutting. In the component bend tests, the water-jet trimmed hole showed delayed fracture at the hole-edges, while the mechanical punched hole showed early fracture as the bending angle increased. In comparing the numerical modeling and test results, the load-displacement curve, the displacement at the onset of cracking, and the final crack shape/length were used. Both failure criteria also enable the numerical model to differentiate between the local formability limit of mechanical-punched and water-jet-trimmed holes. The failure criteria and static bend test developed here are useful to evaluate the local formability limit at a structural component level for automotive crash tests.

  9. Bending fatigue tests on flattened strand wire rope at high working loads

    SciTech Connect

    Wang, R.C.; Shapiro, D.E.

    1995-09-01

    The US Bureau of Mines established a wire rope research laboratory to examine the factors that affect the safety and the useful life of wire rope. In the most recent work, two 32-mm 6x27H flattened strand ropes were degraded on a bending fatigue machine. The two tests were run at constant loads of 285 and 347 kN or safety factors of 2.5 and 2. Nondestructive and tensile strength tests were performed on samples of the ropes to determine the relationship between rope deterioration and rope breaking strength. Neither the area loss nor the number of broken wires measured from nondestructive tests could be used as clear indicators of the loss of strength. However, it was found from the tensile tests for both rope specimens that the strength loss was associated with the reduction of breaking strain. This suggests that measuring the strain of many short sections of a rope in the elastic region may locate the high stress sections and thus determine the condition of the rope.

  10. Nonlinear analysis and redesign of the mixed-mode bending delamination test

    NASA Technical Reports Server (NTRS)

    Reeder, J. R.; Crews, J. H., Jr.

    1991-01-01

    The Mixed Mode Bending (MMB) test uses a lever to simultaneously apply mode I and mode II loading to a split beam specimen. An iterative analysis that accounts for the geometric nonlinearity of the MMB test was developed. The analysis accurately predicted the measured load displacement response and the strain energy release rate, G, of an MMB test specimen made of APC2 (AS4/PEEK). The errors in G when calculated using linear theory were found to be as large as thirty percent in some cases. Because it would be inconvenient to use a nonlinear analysis to analyze MMB data, the MMB apparatus was redesigned to minimize the nonlinearity. The nonlinear analysis was used as a guide in redesigning the MMB apparatus. With the redesigned apparatus, loads were applied through a roller attached to the level and loaded just above the midplane of the test specimen. The redesigned apparatuus has geometric nonlinearity errors of less than three percent, even for materials substantially tougher than APC2. This apparatus was demonstrated by measuring the mixed mode delamination fracture toughness of APC2.

  11. Cracking and Spalling Behavior of HVOF Thermally Sprayed WC-Co-Cr Coating in Bend and Axial Fatigue Tests

    NASA Astrophysics Data System (ADS)

    Gui, M.; Eybel, R.; Asselin, B.; Monerie-Moulin, F.

    2015-03-01

    In this work, WC-10Co-4Cr coating was sprayed by high-velocity oxygen fuel (HVOF) process on Almen strip and axial fatigue coupon. Three-point bend test was used to bend Almen strip coating specimens with tensile and compressive stress applied to the coating. Axial fatigue coating specimens were tested at a load stress of 1250 MPa and a stress ratio of R = -1. Process condition of Thermal spraying was found to have an effect on spalling performance of the coating in the fatigue test. The mechanism of cracking and spalling process in the coating was studied in bend and fatigue conditions. Based on deformation difference between the coating and the substrate, the factors, especially coating thickness, to impact the coating spalling behavior in axial fatigue test are discussed. HVOF-sprayed WC-10Co-4Cr coating matches the deformation of base substrate by cracking when tensile stress is applied in bend and fatigue tests because the coating has very limit deformation capability. In axial fatigue test of WC-10Co-4Cr coating specimen, the substrate works in a stress-to-strain manner; however the coating works in a strain-to-stress manner and is stressed due to the substrate deformation.

  12. [Method to Calculate the Yield Load of Bone Plate in Four-point Bending Test].

    PubMed

    Jia, Xiaohang; Zhou, Jun; Ma, Jun; Wen, Yan

    2015-09-01

    This paper developed a calculation method to acquire the yield load P of bone plate during four-point bending test. This method is based on the displacement--force (δ-F) curve function f(M)(δ) obtained from the test, each slope of the curve was calculated using piecewise smooth function and the line segment in f(M)(δ) elastic deformation area was searched by setting the minimum slope T. Slope S was obtained through linear fit so as to build parallel displacement function f(L)(δ). Then, approximating intersection point of f(M)(δ) and f(L)(δ) was obtained through linear interpolation. Thus, yield load P was acquired. The method in the paper was loyal to YY/T 0342-2002 regulation and was liable to program calculation. The calculating process was nothing to do with whether the initial point during the test was preloaded or unloaded, and there was no need to correct the original point. In addition, T was set in an ideal fitting level guaranteed by the fitting coefficient of determination R2, and thus S was very close to the real value, and P was with a high accuracy.

  13. A new method for fracture toughness determination of graded (Pt,Ni)Al bond coats by microbeam bend tests

    NASA Astrophysics Data System (ADS)

    Jaya B, Nagamani; Jayaram, Vikram; Biswas, Sanjay Kumar

    2012-09-01

    A novel method is proposed for fracture toughness determination of graded microstructurally complex (Pt,Ni)Al bond coats using edge-notched doubly clamped beams subjected to bending. Micron-scale beams are machined using the focused ion beam and loaded in bending under a nanoindenter. Failure loads gathered from the pop-ins in the load-displacement curves combined with XFEM analysis are used to calculate K c at individual zones, free from substrate effects. The testing technique and sources of errors in measurement are described and possible micromechanisms of fracture in such heterogeneous coatings discussed.

  14. In-situ scanning electron microscopy study of fracture events during back-end-of-line microbeam bending tests

    SciTech Connect

    Vanstreels, K. Zahedmanesh, H.; Bender, H.; Gonzalez, M.; De Wolf, I.; Lefebvre, J.; Bhowmick, S.

    2014-11-24

    This paper demonstrates the direct observation of crack initiation, crack propagation, and interfacial delamination events during in-situ microbeam bending tests of FIB milled BEOL structures. The elastic modulus and the critical force of fracture of the BEOL beam samples were compared for beams of different length and width.

  15. Measurements of emittance growth through the achromatic bend at the BNL Accelerator Test Facility

    SciTech Connect

    Wang, X.J.; Kehne, D.

    1997-07-01

    Measurements of emittance growth in a high peak current beam as it passes through an achromatic double bend are summarized. Experiments were performed using the ATF at Brookhaven National Laboratory by X.J. Wang and D. Kehne as a collaboration resulting from the proposal attached at the end of the document. The ATF consists off an RF gun (1 MeV), two sections of linac (40-75 MeV), a diagnostic section immediately following the linac, a 20{degree} bend magnet, a variable aperture slit at a high dispersion point, 5 quadrupoles, then another 20{degree} bend followed by another diagnostic section. The TRANSPORT deck describing the region from the end of the linac to the end of the diagnostic line following the achromatic bends is attached to the end of this document. Printouts of the control screens are also attached.

  16. Elevated-temperature fracture resistances of monolithic and composite ceramics using chevron-notched bend tests

    NASA Technical Reports Server (NTRS)

    Ghosh, Asish; Jenkins, Michael G.; Ferber, Mattison K.; Peussa, Jouko; Salem, Jonathan A.

    1992-01-01

    The quasi-static fracture behaviors of monolithic ceramics (SiC, Si3N4, MgAl2O4), self-reinforced monoliths (acicular grained Si3N4, acicular grained mullite), and ceramic matrix composites (SiC whisker/Al2O3 matrix, TiB2 particulate/SiC matrix, SiC fiber/CVI SiC matrix, Al2O3 fiber/CVI SiC matrix) were measured over the temperature range of 20 to 1400 C. The chevron notched, bend bar test geometry was essential for characterizing the elevated temperature fracture resistances of this wide range of quasi-brittle materials during stable crack growth. Fractography revealed the differences in the fracture behavior of the different materials at the various temperatures. The fracture resistances of the self-reinforced monoliths were comparable to those of the composites and the fracture mechanisms were found to be similar at room temperature. However at elevated temperatures the differences of the fracture behavior became apparent where the superior fracture resistance of the self-reinforced monoliths were attributed to the minor amounts of glassy, intergranular phases which were often more abundant in the composites and affected the fracture behavior when softened by elevated temperatures.

  17. Three Point Bending Test of Human Femoral Tissue: An Essay in Ancient and Modern Bones

    NASA Astrophysics Data System (ADS)

    González-Bárcenas, L. A.; Trejo-Camacho, H.; Suárez-Estrella, I.; Heredia, A.; Magaña, C.; Bucio, L.; Orozco, E.

    2003-09-01

    Some procedures for characterising the mechanical properties of femur diaphysis are reviewed here. We have used the three point bending test to measure the relative rupture modulus of ancient healthy human tissues (1250, 800, 614, and 185 years BP) as well as recent bones. The maximum resistance to fracture was measured applying a force (by a wedge) over the femoral inner surface. The maximum rupture strength was about 150 MPa for recent bone and decreased as the antiquity increased. The typical anisotropy that is observed in this kind of tissues is due to the anisotropical orientation of fibres as well as the textured orientation of the apatite crystals over the collagen fibres. Therefore we found that ancient bones show less fracture strength probably due to an abiotic crystal growth phenomenon during the diagenesis process. By LVSEM analysis we have found that in recent samples the fracture surface is irregular due to the crosslinking interactions between the collagen molecules, in comparison with the ancient samples, where a smooth surface is clearly appreciated as the antiquity of the sample increases. The results reported here strongly suggest that these composites should contain a fibrillar phase as a matrix constituted mainly by a natural polymer (i.e. collagen, cellulose, etc.). Moreover, this composite must have a minimum rupture strength of about 150 MPa.

  18. Elevated-temperature fracture resistances of monolithic and composite ceramics using chevron-notched bend tests

    NASA Technical Reports Server (NTRS)

    Ghosh, Asish; Jenkins, Michael G.; Ferber, Mattison K.; Peussa, Jouko; Salem, Jonathan A.

    1992-01-01

    The quasi-static fracture behaviors of monolithic ceramics (SiC, Si3N4, MgAl2O4), self-reinforced monoliths (acicular grained Si3N4, acicular grained mullite), and ceramic matrix composites (SiC whisker/Al2O3 matrix, TiB2 particulate/SiC matrix, SiC fiber/CVI SiC matrix, Al2O3 fiber/CVI SiC matrix) were measured over the temperature range of 20 to 1400 C. The chevron notched, bend bar test geometry was essential for characterizing the elevated temperature fracture resistances of this wide range of quasi-brittle materials during stable crack growth. Fractography revealed the differences in the fracture behavior of the different materials at the various temperatures. The fracture resistances of the self-reinforced monoliths were comparable to those of the composites and the fracture mechanisms were found to be similar at room temperature. However at elevated temperatures the differences of the fracture behavior became apparent where the superior fracture resistance of the self-reinforced monoliths were attributed to the minor amounts of glassy, intergranular phases which were often more abundant in the composites and affected the fracture behavior when softened by elevated temperatures.

  19. Design and characterization of single-mode holey fibers with low bending losses.

    PubMed

    Tsuchida, Yukihiro; Saitoh, Kunimasa; Koshiba, Masanori

    2005-06-13

    As the fiber-to-the-home network construction increased, optical fiber cables are demanded to be easier to handle and require less space. Under this situation, a single mode fiber (SMF) permitting small bending radius is strongly requested. In this paper, we propose and demonstrate a novel type of bending-insensitive single-mode holey fiber that has a doped core and two layers of holes with different air-hole diameters. The fiber has a mode field diameter of 9.3 microm at 1.55 microm and a cutoff wavelength below 1.1 microm, and shows a bending loss of 0.011 dB/turn at 1.55 microm for a bending radius of 5 mm and a low splice loss of 0.08 dB per fusion-splicing to a conventional SMF.

  20. Mechanical properties of several nickel-titanium alloy wires in three-point bending tests.

    PubMed

    Nakano, H; Satoh, K; Norris, R; Jin, T; Kamegai, T; Ishikawa, F; Katsura, H

    1999-04-01

    The purpose of this study was to clarify the mechanical properties of 42 brands of nickel-titanium alloy orthodontic wires from 9 manufacturers by conducting three-point bending tests under uniform testing conditions. Manufacturers included A-Company, Hoya Medical, Lancer, Ormco, Rocky Mountain, Sankin, Tomy (GAC), TP, and 3M/Unitek. Cobalt-chrome, and titanium-molybdenum alloy wires were also tested as a reference for comparison of force levels. All reported data were recorded during the unloading process to simulate the force that a wire exerts on a tooth as it is moved into the dental arch from a position of malocclusion. The following results were obtained for the nickel-titanium wires tested. (1) Among the 0.016 inch round wires tested under a maximum deflection of 1.5 mm, the difference between the smallest (Copper nickel-titanium 35) and the largest (Aline) load values was 136 g. For the 0.016 x 0.022 inch rectangular wires tested, the difference between the smallest (Copper nickel-titanium 40) and the largest (Aline) load values was 337 g. (2) The change in load between 1.5 and 0.5 mm of deflection was examined to clarify the superelastic properties of the wires tested. For the 0.016 inch wires, 17 wire brands produced a load difference of less than 100 g, and two brands produced a difference of at least 100 g (Aline and Titanal = 100 g). For the 0.016 x 0.022 inch wires, 15 brands produced a load difference of less than 100 g, and eight brands produced a difference of over 100 g. The smallest and largest load differences were 3 g (Copper nickel-titanium 35) and 200 g (Aline). (3) The majority of the samples with a smaller load difference between deflections of 1.5 mm and 0.5 mm in the unloading process were found among super-elastic wires, while samples with a larger load difference were predominantly found among work-hardened wires. Compared with cobalt-chrome and TMA wires, nickel-titanium alloy wires exert significantly less force. However, the amount

  1. Design of GaN-based S-bend Y-branch power splitter with MMI structure

    NASA Astrophysics Data System (ADS)

    Azhar, Arviza; Purnamaningsih, Retno W.

    2015-01-01

    In this work, we have designed GaN based symmetric S-Bend Y-branch power splitter with rectangular MMI structure at telecommunication wavelength. Optimization of the structure parameters required for this structure was conducted accurately by theoretical tools using BPM methods. The simulation results proposed the optimum dimension for the design Y-branch power splitter at relative output power 94.5%.

  2. The effect of core thickness variation of sandwich composite cantala rHDPE on mechanical strength of bending test

    NASA Astrophysics Data System (ADS)

    Setiadi, Andri; Raharjo, Wijang Wisnu; Triyono, Teguh

    2017-01-01

    The components of the sandwich structure using materials not environmentally friendly because it cannot be recycled after its useful life runs out. This research is focused on the effect of core thickness on the bending strength of the composite sandwich-rHDPE cantula. The variation of thickness is 10mm, 15mm, and 20mm. Skin is made only of powder recycled- High-Density Polyethylene (rHDPE), while the core is made of fiber cantula and rHDPE. The process of making skins and cores made using a hot press. The parameter process use includes a process temperature of 170°C, holding time 15minutes and the pressing pressure of 50bar. Dimensions and bending testing refer to ASTM C 393 for the dimension and compression testing method. The results showed that variations thickness core effect on the bending strength and compression strength of the composite sandwich-rHDPEcantula. The highest bending strength of 23,56Mpa MPa was obtained with core thickness 20mm.

  3. Effect of ball geometry on endurance limit in bending of drilled balls

    NASA Technical Reports Server (NTRS)

    Munson, H. E.

    1975-01-01

    Four designs of drilled (cylindrically hollow) balls were tested for resistance to bending fatigue. Bending fatigue has been demonstrated to be a limiting factor in previous evaluations of the drilled ball concept. A web reinforced drilled ball was most successful in resisting bending fatigue. Another design of through drilled design, involving a heavier wall than the standard reference ball, also showed significant improvement in resistance to bending fatigue.

  4. Load-displacement measurement and work determination in three-point bend tests of notched or precracked specimens

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    Suggestions for testing of notched or cracked three-point bend specimens are presented which: (1) correct displacement measurement errors resulting from misalignment between the load applicator and specimen; (2) account for coincidental strains not associated with the work of crack extension; (3) simplify record analysis and processing; and (4) extend displacement gage range without sacrifice of sensitivity or accuracy. These testing details are particularly applicable to procedures in which the crack extension force is determined from the work done on the specimen.

  5. Manipulating surface plasmon waves by transformation optics: Design examples of a beam squeezer, bend, and omnidirectional absorber

    NASA Astrophysics Data System (ADS)

    Yu, Zhen-Zhong; Feng, Yi-Jun; Wang, Zheng-Bin; Zhao, Jun-Ming; Jiang, Tian

    2013-03-01

    We present several design examples of how to apply transformation optics and curved space under coordinate transformation to manipulating the surface plasmon waves in a controlled manner. We demonstrate in detail the design procedure of the plasmonic wave squeezer, in-plane bend and omnidirectional absorber. We show that the approximation method of modifying only the dielectric material of a dielectric-metal surface of the plasmonic device could lead to acceptable performance, which facilitates the fabrication of the device. The functionality of the proposed plasmonic device is verified using three-dimensional full-wave electromagnetic simulations. Aiming at practical realization, we also show the design of a plasmonic in-plane bend and omnidirectional absorber by an alternative transformation scheme, which results in a simple device structure with a tapered isotropic dielectric cladding layer on the top of the metal surface that can be fabricated with existing nanotechnology.

  6. Numerical Analysis of AHSS Fracture in a Stretch-bending Test

    NASA Astrophysics Data System (ADS)

    Luo, Meng; Chen, Xiaoming; Shi, Ming F.; Shih, Hua-Chu

    2010-06-01

    Advanced High Strength Steels (AHSS) are increasingly used in the automotive industry due to their superior strength and substantial weight reduction advantage. However, their limited ductility gives rise to numerous manufacturing issues. One of them is the so-called `shear fracture' often observed on tight radii during stamping processes. Since traditional approaches, such as the Forming Limit Diagram (FLD), are unable to predict this type of fracture, efforts have been made to develop failure criteria that can predict shear fractures. In this paper, a recently developed Modified Mohr-Coulomb (MMC) ductile fracture criterion[1] is adopted to analyze the failure behavior of a Dual Phase (DP) steel sheet during stretch bending operations. The plasticity and ductile fracture of the present sheet are fully characterized by the Hill'48 orthotropic model and the MMC fracture model respectively. Finite Element models with three different element types (3D, shell and plane strain) were built for a Stretch Forming Simulator (SFS) test and numerical simulations with four different R/t ratios (die radius normalized by sheet thickness) were performed. It has been shown that the 3D and shell element models can accurately predict the failure location/mode, the upper die load-displacement responses as well as the wall stress and wrap angle at the onset of fracture for all R/t ratios. Furthermore, a series of parametric studies were conducted on the 3D element model, and the effects of tension level (clamping distance) and tooling friction on the failure modes/locations were investigated.

  7. Local strain and damage mapping in single trabeculae during three-point bending tests.

    PubMed

    Jungmann, R; Szabo, M E; Schitter, G; Tang, Raymond Yue-Sing; Vashishth, D; Hansma, P K; Thurner, P J

    2011-05-01

    The use of bone mineral density as a surrogate to diagnose bone fracture risk in individuals is of limited value. However, there is growing evidence that information on trabecular microarchitecture can improve the assessment of fracture risk. One current strategy is to exploit finite element analysis (FEA) applied to 3D image data of several mm-sized trabecular bone structures obtained from non-invasive imaging modalities for the prediction of apparent mechanical properties. However, there is a lack of FE damage models, based on solid experimental facts, which are needed to validate such approaches and to provide criteria marking elastic-plastic deformation transitions as well as microdamage initiation and accumulation. In this communication, we present a strategy that could elegantly lead to future damage models for FEA: direct measurements of local strains involved in microdamage initiation and plastic deformation in single trabeculae. We use digital image correlation to link stress whitening in bone, reported to be correlated to microdamage, to quantitative local strain values. Our results show that the whitening zones, i.e. damage formation, in the presented loading case of a three-point bending test correlate best with areas of elevated tensile strains oriented parallel to the long axis of the samples. The average local strains along this axis were determined to be (1.6±0.9)% at whitening onset and (12±4)% just prior to failure. Overall, our data suggest that damage initiation in trabecular bone is asymmetric in tension and compression, with failure originating and propagating over a large range of tensile strains.

  8. Local strain and damage mapping in single trabeculae during three-point bending tests

    PubMed Central

    Jungmann, R.; Szabo, M.E.; Schitter, G.; Tang, Raymond Yue-Sing; Vashishth, D.; Hansma, P.K.; Thurner, P.J.

    2012-01-01

    The use of bone mineral density as a surrogate to diagnose bone fracture risk in individuals is of limited value. However, there is growing evidence that information on trabecular microarchitecture can improve the assessment of fracture risk. One current strategy is to exploit finite element analysis (FEA) applied to 3D image data of several mm-sized trabecular bone structures obtained from non-invasive imaging modalities for the prediction of apparent mechanical properties. However, there is a lack of FE damage models, based on solid experimental facts, which are needed to validate such approaches and to provide criteria marking elastic–plastic deformation transitions as well as microdamage initiation and accumulation. In this communication, we present a strategy that could elegantly lead to future damage models for FEA: direct measurements of local strains involved in microdamage initiation and plastic deformation in single trabeculae. We use digital image correlation to link stress whitening in bone, reported to be correlated to microdamage, to quantitative local strain values. Our results show that the whitening zones, i.e. damage formation, in the presented loading case of a three-point bending test correlate best with areas of elevated tensile strains oriented parallel to the long axis of the samples. The average local strains along this axis were determined to be (1.6 ± 0.9)% at whitening onset and (12 ± 4)% just prior to failure. Overall, our data suggest that damage initiation in trabecular bone is asymmetric in tension and compression, with failure originating and propagating over a large range of tensile strains. PMID:21396601

  9. Design of a triple-bend isochronous achromat with minimum coherent-synchrotron-radiation-induced emittance growth

    NASA Astrophysics Data System (ADS)

    Venturini, M.

    2016-06-01

    Using a 1D steady-state free-space coherent synchrotron radiation (CSR) model, we identify a special design setting for a triple-bend isochronous achromat that yields vanishing emittance growth from CSR. When a more refined CSR model with transient effects is included in the analysis, numerical simulations show that the main effect of the transients is to shift the emittance growth minimum slightly, with the minimum changing only modestly.

  10. Fracture-toughness tests and displacement and crack-stability analyses of round-bar bend specimens of liquid-phase-sintered tungsten. Final report

    SciTech Connect

    Underwood, J.H.; Baratta, F.I.; Zalinka, J.J.

    1991-10-01

    Plane strain fracture toughness tests were performed using the recently proposed round bar bend test procedure with a liquid-phase sintered tungsten alloy. The tests included a direct comparison of fracture toughness from rectangular and round bend specimens and measurements of load line compliance using the unloading technique of J integral fracture tests. Complementary displacement and crack growth stability analyses of the round bar were performed as an extension of recent work in these two areas.

  11. Effects of subcritical crack growth on fracture toughness of ceramics assessed in chevron-notched three-point bend tests

    NASA Technical Reports Server (NTRS)

    Chao, L. Y.; Singh, D.; Shetty, D. K.

    1988-01-01

    A numerical computational study was carried out to assess the effects of subcritical crack growth on crack stability in the chevron-notched three-point bend specimens. A power-law relationship between the subcritical crack velocity and the applied stress intensity were used along with compliance and stress-intensity relationships for the chevron-notched bend specimen to calculate the load response under fixed deflection rate and a machine compliance. The results indicate that the maximum load during the test occurs at the same crack length for all the deflection rates; the maximum load, however, is dependent on the deflection rate for rates below the critical rate. The resulting dependence of the apparent fracture toughness on the deflection rate is compared to experimental results on soda-lime glass and polycrystalline alumina.

  12. Effects of subcritical crack growth on fracture toughness of ceramics assessed in chevron-notched three-point bend tests

    NASA Technical Reports Server (NTRS)

    Chao, L. Y.; Singh, D.; Shetty, D. K.

    1988-01-01

    A numerical computational study was carried out to assess the effects of subcritical crack growth on crack stability in the chevron-notched three-point bend specimens. A power-law relationship between the subcritical crack velocity and the applied stress intensity were used along with compliance and stress-intensity relationships for the chevron-notched bend specimen to calculate the load response under fixed deflection rate and a machine compliance. The results indicate that the maximum load during the test occurs at the same crack length for all the deflection rates; the maximum load, however, is dependent on the deflection rate for rates below the critical rate. The resulting dependence of the apparent fracture toughness on the deflection rate is compared to experimental results on soda-lime glass and polycrystalline alumina.

  13. Effect of mixed convection and u-bends on the design of double-pipe heat exchangers

    SciTech Connect

    Abdelmessih, A.N.; Bell, K.J.

    1999-09-01

    For horizontal flow in the laminar flow regimen, the interaction between natural and forced convection and the effect of the secondary flow induced by an unheated U-bend were considered in developing an empirical correlation for the nearly uniform heat flux condition. The correlation predicts the local peripheral average heat transfer coefficient with an absolute average deviation of 9.9%. In this article the mechanisms involved in laminar flow with the presence of a U-bend are explained. The realistic behavior of the correlation is illustrated. Also, a brief discussion of some of the existing correlations for laminar flow is presented. Four cases showing the practicality of using the correlation in the design of horizontal double-pipe heat exchangers are demonstrated.

  14. Multiaxial pedicle screw designs: static and dynamic mechanical testing.

    PubMed

    Stanford, Ralph Edward; Loefler, Andreas Herman; Stanford, Philip Mark; Walsh, William R

    2004-02-15

    Randomized investigation of multiaxial pedicle screw mechanical properties. Measure static yield and ultimate strengths, yield stiffness, and fatigue resistance according to an established model. Compare these measured properties with expected loads in vivo. Multiaxial pedicle screws provide surgical versatility, but the complexity of their design may reduce their strength and fatigue resistance. There is no published data on the mechanical properties of such screws. Screws were assembled according to a vertebrectomy model for destructive mechanical testing. Groups of five assemblies were tested in static tension and compression and subject to three cyclical loads. Modes of failure, yield, and ultimate strength, yield stiffness, and cycles to failure were determined for six designs of screw. Static compression yield loads ranged from 217.1 to 388.0 N and yield stiffness from 23.7 to 38.0 N/mm. Cycles to failure ranged from 42 x 10(3) to 4,719 x 10(3) at 75% of static ultimate load. There were significant differences between designs in all modes of testing. Failure occurred at the multiaxial link in static and cyclical compression. Bending yield strengths just exceeded loads expected in vivo. Multiaxial designs had lower static bending yield strength than fixed screw designs. Five out of six multiaxial screw designs achieved one million cycles at 200 N in compression bending. "Ball-in-cup" multiaxial locking mechanisms were vulnerable to fatigue failure. Smooth surfaces and thicker material appeared to be protective against fatigue failure.

  15. Load-displacement measurement and work determination in three-point bend tests of notched or precracked specimens

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    Suggestions for testing of notched or cracked three-point bend specimens are presented that (1) correct displacement measurement errors resulting from misalignment between the load applicator and specimen; (2) account for coincidental strains not associated with the work of crack extension; (3) simplify record analysis and processing; and (4) extend displacement gage range without sacrifice of sensitivity or accuracy. These testing details are particularly applicable to procedures in which the crack extension force J(I) is determined from the work done on the specimen.

  16. Long-Term Immersion Testing of Alloy 22 and Titanium Grade 7 Double U-bend Specimens

    SciTech Connect

    Evans, K J; Stuart, M L; Hailey, P D; Rebak, R B

    2007-02-08

    Double U-bend specimens of Alloy 22 (N06022) and Titanium Grade 7 (R52400) were exposed to a naturally aerated concentrated Basic Saturated Water (BSW) electrolyte at 105 C for over six years. Different type of discoloration of the Ti Gr 7 and Alloy 22 specimens was observed. General Corrosion was minimal and not distinguishable under a scanning electron microscope. None of the tested specimens suffered environmentally assisted cracking (EAC) or localized corrosion under the tested conditions. The specimens retained their residual stress after the long environmental exposure.

  17. Design of a hybrid spoof plasmonic sub-terahertz waveguide with low bending loss in a broad frequency band.

    PubMed

    Moghaddam, Mohammad Ali Khosrovani; Ahmadi-Boroujeni, Mehdi

    2017-03-20

    The effect of dielectric cladding on the waveguiding characteristics of an array of metallic pillars on a metal plane in the sub-terahertz band is explored. Firstly, a 2D structure made up of a metallic grating of infinite lateral width with various dielectric overlays is analytically studied to get more insight into the problem. Then the ideas inferred from the 2D structure are applied to the realistic 3D structure that has a finite lateral width. It is shown that by proper design of the dielectric medium surrounding the metallic structure the modal field confinement can be enhanced in a broad frequency band resulting in a low bending loss. Especially, by integrating the pillars into a silicon channel of finite size and evacuating the spaces between them a highly confined spoof surface plasmon is supported and a considerable reduction in the bending loss over a broad bandwidth is observed. Due to small cross-sectional size, low bending loss and ease of fabrication, the proposed waveguide is a promising choice for millimeter-wave and terahertz integrated circuits; particularly those based on the silicon technology.

  18. An ion-optical design study of a carbon-ion rotating gantry with a superconducting final bending magnet

    NASA Astrophysics Data System (ADS)

    Bokor, J.; Pavlovič, M.

    2016-03-01

    Ion-optical designs of an isocentric ion gantry with a compact curved superconducting final bending magnet are presented. The gantry is designed for transporting carbon-therapy beams with nominal kinetic energy of 400 MeV/u, which corresponds to the penetration range of C6+ beam in water of about 28 cm. In contrast to other existing designs, we present a ;hybrid; beam transport system containing a single superconducting element - the last bending magnet. All other elements are based on conventional warm technology. Ion-optical properties of such a hybrid system are investigated in case of transporting non-symmetric (i.e. different emittance patterns in the horizontal and vertical plane) beams. Different conditions for transporting the non-symmetric beams are analyzed aiming at finding the optimal, i.e. the most compact, gantry version. The final gantry layout is presented including a 2D parallel scanning. The ion-optical and scanning properties of the final gantry design are described, discussed and illustrated by computer simulations performed by WinAGILE.

  19. Test Analysis Correlation of the Single Stringer Bending Tests for the Space Shuttle ET-137 Intertank Stringer Crack Investigation

    NASA Technical Reports Server (NTRS)

    Phillips, Dawn R.; Saxon, Joseph B.; Wingate, Robert J.

    2012-01-01

    , occurred as the LOX liquid level crossed the LOX tank / Intertank interface ring frame. Hence, cryogenically-induced displacements were suspected as a contributing cause of the stringer cracks. To study the behavior of Intertank stringers subjected to similar displacements, static load tests of individual stringers, colloquially known as "single stringer bending tests" were performed. Approximately thirty stringers were tested, many of which were cut from the partially completed Intertank for what would have been ET-139. In addition to the tests, finite element (FE) analyses of the test configuration were also performed. In this paper, the FE analyses and test-analysis correlation for stringer test S6-8 are presented. Stringer S6-8 is a "short chord" configuration with no doubler panels.

  20. Hydrogen-enhanced cracking revealed by in situ micro-cantilever bending test inside environmental scanning electron microscope.

    PubMed

    Deng, Yun; Hajilou, Tarlan; Barnoush, Afrooz

    2017-07-28

    To evaluate the hydrogen (H)-induced embrittlement in iron aluminium intermetallics, especially the one with stoichiometric composition of 50 at.% Al, a novel in situ micro-cantilever bending test was applied within an environmental scanning electron microscope (ESEM), which provides both a full process monitoring and a clean, in situ H-charging condition. Two sets of cantilevers were analysed in this work: one set of un-notched cantilevers, and the other set with focused ion beam-milled notch laying on two crystallographic planes: (010) and (110). The cantilevers were tested under two environmental conditions: vacuum (approximately 5 × 10(-4) Pa) and ESEM (450 Pa water vapour). Crack initiation at stress-concentrated locations and propagation to cause catastrophic failure were observed when cantilevers were tested in the presence of H; while no cracking occurred when tested in vacuum. Both the bending strength for un-notched beams and the fracture toughness for notched beams were reduced under H exposure. The hydrogen embrittlement (HE) susceptibility was found to be orientation dependent: the (010) crystallographic plane was more fragile to HE than the (110) plane.This article is part of the themed issue 'The challenges of hydrogen and metals'. © 2017 The Author(s).

  1. Hydrogen-enhanced cracking revealed by in situ micro-cantilever bending test inside environmental scanning electron microscope

    NASA Astrophysics Data System (ADS)

    Deng, Yun; Hajilou, Tarlan; Barnoush, Afrooz

    2017-06-01

    To evaluate the hydrogen (H)-induced embrittlement in iron aluminium intermetallics, especially the one with stoichiometric composition of 50 at.% Al, a novel in situ micro-cantilever bending test was applied within an environmental scanning electron microscope (ESEM), which provides both a full process monitoring and a clean, in situ H-charging condition. Two sets of cantilevers were analysed in this work: one set of un-notched cantilevers, and the other set with focused ion beam-milled notch laying on two crystallographic planes: (010) and (110). The cantilevers were tested under two environmental conditions: vacuum (approximately 5 × 10-4 Pa) and ESEM (450 Pa water vapour). Crack initiation at stress-concentrated locations and propagation to cause catastrophic failure were observed when cantilevers were tested in the presence of H; while no cracking occurred when tested in vacuum. Both the bending strength for un-notched beams and the fracture toughness for notched beams were reduced under H exposure. The hydrogen embrittlement (HE) susceptibility was found to be orientation dependent: the (010) crystallographic plane was more fragile to HE than the (110) plane. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  2. An acoustic bending waveguide designed by anisotropic density-near-zero metamaterial

    NASA Astrophysics Data System (ADS)

    Wang, Yang-Yang; Ding, Er-Liang; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2016-12-01

    Anisotropic metamaterial with only one component of the mass density tensor near zero (ADNZ) is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize perfect bending waveguides. According to a coordinate transformation, the surface waves on the input and output interfaces of the ADNZ metamaterial induces the sound energy flow to be redistributed and match smoothly with the propagating modes inside the metamaterial waveguide. According to the theory of bending waveguide, we realize the “T”-type sound shunting and convergence, as well as acoustic channel selection by embedding small-sized defects. Numerical calculations are performed to confirm the above effects. Project supported by the National Basic Research Program of China (Grant No. 2012CB921504), the National Natural Science Foundation of China (Grant No. 11474160), the Fundamental Research Funds for the Central Universities, China (Grant No. 020414380001), the State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLA201609), and the Priority Academic Program Development of Jiangsu Higher Education Institution, China.

  3. Design of guide vanes for minimizing the pressure loss in sharp bends

    NASA Astrophysics Data System (ADS)

    Sahlin, Alexander; Johansson, Arne V.

    1991-08-01

    A guide-vane section was designed with the aim of minimizing the pressure drop for flow in a 90-deg corner. A central part of the design process was to use potential flow calculations in order to obtain a vane geometry such that the velocity distribution on the suction side replicates that of a chosen single airfoil at the angle of attack for maximum lift/drag in a straight free stream. The choice was based on proven good drag characteristics at low Reynolds numbers. For the design of the pressure-side velocity, distribution advantage of the expansion in the middle part of the cascade was taken to obtain a high pressure coefficient on the pressure side, as compared to the single airfoil case. Vanes were built and tested in a special-purpose wind tunnel. The 2D pressure-loss coefficient, as measured downstream of a five-vane corner, was found to be as low as 0.036, which is about one-fifth of that for traditional quarter-circle-shaped vanes.

  4. The design and experiment of a novel ultrasonic motor based on the combination of bending modes.

    PubMed

    Yan, Jipeng; Liu, Yingxiang; Liu, Junkao; Xu, Dongmei; Chen, Weishan

    2016-09-01

    This paper presents a new-type linear ultrasonic motor which takes advantage of the combination of two orthogonal bending vibration modes. The proposed ultrasonic motor consists of eight pieces of PZT ceramic plates and a metal beam that includes two cone-shaped horns and a cylindrical driving foot. The finite element analyses were finished to verify the working principle of the proposed motor. The mode shapes of the motor were obtained by modal analysis; the elliptical trajectories of nodes on the driving foot were obtained by time-domain analysis. Based on the analyses, a prototype of the proposed motor was fabricated and measured. The mechanical output characteristics were obtained by experiments. The maximal velocity of the proposed motor is 735mm/s and the maximal thrust is 1.1N.

  5. Bending testing and characterization of surrogate nuclear fuel rods made of Zircaloy-4 cladding and aluminum oxide pellets

    NASA Astrophysics Data System (ADS)

    Wang, Hong; Wang, Jy-An John

    2016-10-01

    Behavior of surrogate nuclear fuel rods made of Zircaloy-4 (Zry-4) cladding with alumina pellets under reversed cyclic bending was studied. Tests were performed under load or moment control at 5 Hz. The surrogate rods fractured under moment amplitudes greater than 10.16 Nm with fatigue lives between 2.4 × 103 and 2.2 × 106 cycles. Fatigue response of Zry-4 cladding was characterized by using flexural rigidity. Degradation of flexural rigidity was shown to depend on the moment and the prefatigue condition of specimens. Pellet-to-pellet interface (PPI), pellet-to-cladding interface (PCI), and pellet condition affect surrogate rod failure. Both debonding of PPI/PCI and pellet fracturing contribute to surrogate rod bending fatigue. The effect of sensor spacing on curvature measurement using three-point deflections was studied; the method based on effective gauge length is effective in sensor spacing correction. The database developed and the understanding gained in this study can serve as input to analysis of SNF (spent nuclear fuel) vibration integrity.

  6. Bending testing and characterization of surrogate nuclear fuel rods made of Zircaloy-4 cladding and aluminum oxide pellets

    SciTech Connect

    Wang, Hong; Wang, Jy-An John

    2016-07-20

    We studied behavior of surrogate nuclear fuel rods made of Zircaloy-4 (Zry-4) cladding with alumina pellets under reversed cyclic bending. Tests were performed under load or moment control at 5 Hz, and an empirical correlation was established between rod fatigue life and amplitude of the applied moment. Fatigue response of Zry-4 cladding was further characterized by using flexural rigidity. Degradation of flexural rigidity was shown to depend on the moment applied and the prefatigue condition of specimens. Pellet-to-pellet interface (PPI), pellet-to-cladding interface (PCI), and pellet condition all affect surrogate rod failure. Bonding/debonding of PPI/PCI and pellet fracturing contribute to surrogate rod bending fatigue. Also, the effect of sensor spacing on curvature measurement using three-point deflections was studied; the method based on effective specimen gauge length is effective in sensor spacing correction. Finally, we developed the database and gained understanding in this study such that it will serve as input to analysis of SNF vibration integrity.

  7. Bending testing and characterization of surrogate nuclear fuel rods made of Zircaloy-4 cladding and aluminum oxide pellets

    DOE PAGES

    Wang, Hong; Wang, Jy-An John

    2016-07-20

    We studied behavior of surrogate nuclear fuel rods made of Zircaloy-4 (Zry-4) cladding with alumina pellets under reversed cyclic bending. Tests were performed under load or moment control at 5 Hz, and an empirical correlation was established between rod fatigue life and amplitude of the applied moment. Fatigue response of Zry-4 cladding was further characterized by using flexural rigidity. Degradation of flexural rigidity was shown to depend on the moment applied and the prefatigue condition of specimens. Pellet-to-pellet interface (PPI), pellet-to-cladding interface (PCI), and pellet condition all affect surrogate rod failure. Bonding/debonding of PPI/PCI and pellet fracturing contribute to surrogatemore » rod bending fatigue. Also, the effect of sensor spacing on curvature measurement using three-point deflections was studied; the method based on effective specimen gauge length is effective in sensor spacing correction. Finally, we developed the database and gained understanding in this study such that it will serve as input to analysis of SNF vibration integrity.« less

  8. Bending testing and characterization of surrogate nuclear fuel rods made of Zircaloy-4 cladding and aluminum oxide pellets

    SciTech Connect

    Wang, Hong; Wang, Jy-An John

    2016-07-20

    We studied behavior of surrogate nuclear fuel rods made of Zircaloy-4 (Zry-4) cladding with alumina pellets under reversed cyclic bending. Tests were performed under load or moment control at 5 Hz, and an empirical correlation was established between rod fatigue life and amplitude of the applied moment. Fatigue response of Zry-4 cladding was further characterized by using flexural rigidity. Degradation of flexural rigidity was shown to depend on the moment applied and the prefatigue condition of specimens. Pellet-to-pellet interface (PPI), pellet-to-cladding interface (PCI), and pellet condition all affect surrogate rod failure. Bonding/debonding of PPI/PCI and pellet fracturing contribute to surrogate rod bending fatigue. Also, the effect of sensor spacing on curvature measurement using three-point deflections was studied; the method based on effective specimen gauge length is effective in sensor spacing correction. Finally, we developed the database and gained understanding in this study such that it will serve as input to analysis of SNF vibration integrity.

  9. Design considerations for a novel shape-memory-plate osteosynthesis allowing for non-invasive alteration of bending stiffness.

    PubMed

    Krämer, Manuel; Müller, Christian W; Hermann, Maike; Decker, Sebastian; Springer, André; Overmeyer, Ludger; Hurschler, Christof; Pfeifer, Ronny

    2017-08-23

    Biomechanical stimuli play a major role in fracture healing. Changing the fixation stiffness through the course of healing might accelerate bone healing and prevent healing complications. Shape memory alloy (SMA) based implants were developed to allow for non-invasive stiffness alteration during the fracture healing process. To gain a deeper understanding of the implant functionality based on the alloy characteristics and geometric design, the mechanical properties of different shape memory alloys where mechanically characterized. SMA bone plates were manufactured and the structural bending stiffness of the implants was determined at different temperatures and configurations. The temperature required for complete recovery of shape after deformation increased continuously with increasing pseudo-plastic deformation in SMA probes. Full recovery was observed at temperatures ranging from 38°C to 52°C after pseudo-plastic deformations ranging from 0.2% to 1.0% outer fibre strain, respectively. The small fragment inverse-dynamisation implants revealed bending stiffnesses ranging from 0.09Nm(2) to 0.34Nm(2) in the initial state and from 0.16Nm(2) to 0.46Nm(2) after shape alteration. Dependent on the design, a relative gain of the implant stiffness ranging from 18.8% to 115.0% could be observed. The large inverse-dynamisation implants revealed bending stiffnesses from 3.7Nm(2) to 7.1Nm(2) before and 4.1Nm(2) to 12.6Nm(2) after triggering the shape memory effect. Dependent on the design a gain in stiffness from 11.8% to 117.2% was observed. Warming the SMA implant to 40°C for a short period of time, leads to a moderate increase in implant stiffness of up to 64.5%, while triggering the implant with 50°C leads to a maximum increase in stiffness of up to 127.3%. The Nitinol shape memory bone plates have a huge potential for improving the treatment of long shaft fractures by allowing for the increase, decrease or incremental change of implant stiffness in fracture

  10. Enhancing propulsive efficiency through proper design of bending patterns of a flexible pitching foil

    NASA Astrophysics Data System (ADS)

    Zeyghami, Samane; Akoz, Emre; Moored, Keith

    2016-11-01

    Many aquatic animals propel themselves efficiently through water by oscillating flexible fins. These fins are, however, not homogeneously flexible, but instead their flexural rigidity varies along their chord and span. To detail the flow structures and propulsive performance of these functionally-graded propulsors a simple model of an unsteady pitching airfoil with a flexible hinge of varying location is examined. This acts as a first-order model of a functionally-graded fin by varying both the flexibility and bending pattern of the propulsor. Recent experiments have shown that adding a flexible 'tail' with the proper stiffness to a rigid pitching foil can effectively delay/suppress the formation of a deflected wake thereby enhancing the cycle-averaged wake momentum in the swimming direction. To extend these observations, we investigate the dependency of the wake pattern of a hinged pitching airfoil to the location and flexibility of the hinge by employing a fast boundary element method solver that is strongly coupled with a torsional spring structural model. The observed wake patterns are further connected to the thrust production and propulsive efficiency with the goal of determining the proper combinations of parameters that yields the maximum gain in efficiency. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI Grant Number N00014-14-1-0533.

  11. International round robin test of the retained critical current after double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires

    NASA Astrophysics Data System (ADS)

    Yamada, Y.; Nishijima, G.; Osamura, K.; Shin, H. S.; Goldacker, W.; Breschi, M.; Ribani, P.

    2016-02-01

    An international round robin test was carried out in order to establish a test method for retained critical current after double bending at room temperature of Ag-sheathed Bi-2223 superconducting wires. Tests for commercial Bi-2223 tape were conducted by six laboratories using the same guidelines. The standard uncertainties (SUs) of measurands were evaluated for these four quantities: I C0, I C/I C080, I C/I C060, I C/I C050, where, I C0 is initial critical current and I C /I C0XX is critical current after XX mm bending. Using an F test to determine where the most scatter was generated in the test results it was found that the greatest scatter in the normalized critical current measurements came from inter-laboratory scatter. In a type-B uncertainty evaluation, the major contribution was from the bending diameter and measuring temperature. The relative SU tended to increase as the bending diameter decreased. A specific mandrel diameter corresponding to a retained critical current of 95% could be determined with a relative SU of 1.3%. In order to reduce the overall scatter, the temperature difference between the critical current measurements before and after bending should be small.

  12. Capability Test Design and Analysis

    DTIC Science & Technology

    2009-01-13

    UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Joint Test and Evaluation Methodology (JTEM),Washington,DC,20301 8. PERFORMING...refinement process for testing in a joint environment (TIJE) 2. Review the methods and processes for an evaluation strategy refinement process 3...Environment System Design Document (SDD) JTEM Capability Test Methodology (CTM) v2.0 Event Management Plan Test Plan Joint Capability Evaluation (JCE

  13. Initiation and Propagation Behaviors of Fatigue Cracks in 5056 Aluminum Alloy Studied by Rotating-Bending Tests with Smooth Specimen

    NASA Astrophysics Data System (ADS)

    Shikama, Takahiro; Yoshihara, Shinji; Aiura, Tadashi; Lee, Dongsun; Noguchi, Hiroshi

    The fatigue properties of the 5056 aluminum alloy, which is the highest Mg-rich alloy among the commercial Al-Mg alloys and exhibits high work hardening and strain aging, was investigated. Rotating-bending tests using smooth specimens were performed at room temperature with the stress ratio R=-1 and frequency of stress cycle f =55 Hz. The experimental results showed that a distinct fatigue limit as in the case of steel existed on the S-N curve. Surface observations using the replica method revealed a wavy pattern around the second phase particle for N=106-107, but no non-propagation cracks were observed. It was speculated that the observed fatigue limit appeared as a result of high work hardening rate and strain aging in the heavily deformed zone, and the fatigue cracks did not initiate from this zone up to the maximum number of stress cycle, N=3.5×107, in the present study.

  14. Mixed-mode I+II fracture characterization of human cortical bone using the Single Leg Bending test.

    PubMed

    Silva, F G A; de Moura, M F S F; Dourado, N; Xavier, J; Pereira, F A M; Morais, J J L; Dias, M I R

    2016-02-01

    Mixed-mode I+II fracture characterization of human cortical bone was analyzed in this work. A miniaturized version of the Single Leg Bending test (SLB) was used owing to its simplicity. A power law criterion was verified to accurately describe the material fracture envelop under mixed-mode I+II loading. The crack tip opening displacements measured by digital image correlation were used in a direct method to determine the cohesive law mimicking fracture behavior of cortical bone. Cohesive zone modeling was used for the sake of validation. Several fracture quantities were compared with the experimental results and the good agreement observed proves the appropriateness of the proposed procedure for fracture characterization of human bone under mixed-mode I+II loading.

  15. Field Bending Tests of Three Riparian Species Common to the Central Platte River: Resistance, Rigidity and Plant Streamlining

    NASA Astrophysics Data System (ADS)

    Thomas, R. E.; Bankhead, N. L.; Simon, A.

    2010-12-01

    The braided Platte River, central Nebraska, was described by the 19th Century wit Artemus Ward as being “a mile wide and an inch deep”. 150 years on, the upstream diversion and storage of water for agricultural, municipal and industrial uses has caused significant alteration of the hydrologic regime. As a result, sandbars have been progressively colonized by vegetation, leading to the formation of semi-permanent islands and the narrowing of braids by 30-90%. In response, a program was initiated early in 2007 to recreate habitat for endangered birds. One potential management strategy is to modify the hydrologic regime with the goal of removing vegetation and hence re-establishing a dynamic braided channel. An interdisciplinary approach has been adopted to evaluate the likelihood for successful implementation of such a strategy. In a companion paper, Bankhead et al. describe field tests conducted to quantify the forces necessary to uproot and/or break the stems and roots of four common riparian species. Herein, we describe field measurements of the behavior of reed canary grass, phragmites australis and cottonwood plants in response to being pulled horizontally at a known height above the ground. During the tests, the extent of plant bending in response to the applied force and the resistance to bending were monitored continuously. Furthermore, a novel approach employing time lapse photography and image processing was used to quantify associated changes in plant projected area. The mean stem diameter of reed canary grass plants was 3.21 ± 1.08 mm (μ ± σ, n = 69), that of phragmites australis plants was 6.05 ± 1.95 mm (n = 90), and that of cottonwood plants was 4.18 ± 3.59 mm (n = 76). The mean stem length of reed canary grass was 0.77 ± 0.35 m (n = 69), that of phragmites australis was 0.86 ± 0.64 m (n = 90), and that of cottonwoods was 0.55 ± 0.43 m (n = 76). The flexural rigidities (J) of cottonwoods were particularly sensitive to plant age: for 1 year

  16. Bending fatigue tests on SiC-Al tapes under alternating stress at room temperature

    NASA Technical Reports Server (NTRS)

    Herzog, J. A.

    1981-01-01

    The development of a testing method for fatigue tests on SiC-Al tapes containing a small amount of SiC filaments under alternating stress is reported. The fatigue strength curves resulting for this composite are discussed. They permit an estimate of its behavior under continuous stress and in combination with various other matrices, especially metal matrices.

  17. Relationships between Loblolly Pine small clear specimens and Dimension Lumber Tested in Static Bending

    Treesearch

    Mark Alexander Butler; Joseph Dahlen; Finto Antony; Michael Kane; Thomas L. Eberhardt; Huizhe Jin; Kim Love-Myers; John Paul McTague

    2016-01-01

    Prior to the 1980s, the allowable stresses for lumber in North America were derived from testing of small clear specimens. However, the procedures were changed because these models were found to be inaccurate. Nevertheless, small clear testing continues to be used around the world for allowable stress determinations and in studies that examine forest management impacts...

  18. LSP Composite Test Bed Design

    NASA Technical Reports Server (NTRS)

    Day, Arthur C.; Griess, Kenneth H.

    2013-01-01

    This document provides standalone information for the Lightning Strike Protection (LSP) Composite Substrate Test Bed Design. A six-sheet drawing set is reproduced for reference, as is some additional descriptive information on suitable sensors and use of the test bed.

  19. Questions Dog Design of Tests

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    On the verge of signing a contract to help design assessments for the common standards, ACT Inc. has withdrawn from the project amid conflict-of-interest questions sparked by its own development of a similar suite of tests. Even though it involves only a small subcontract, the move by the Iowa-based test-maker, and the questions from the state…

  20. Questions Dog Design of Tests

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    On the verge of signing a contract to help design assessments for the common standards, ACT Inc. has withdrawn from the project amid conflict-of-interest questions sparked by its own development of a similar suite of tests. Even though it involves only a small subcontract, the move by the Iowa-based test-maker, and the questions from the state…

  1. A novel method of strain - bending moment calibration for blade testing

    NASA Astrophysics Data System (ADS)

    Greaves, P.; Prieto, R.; Gaffing, J.; van Beveren, C.; Dominy, R.; Ingram, G.

    2016-09-01

    A new method of interpreting strain data in full scale static and fatigue tests has been implemented as part of the Offshore Renewable Energy Catapult's ongoing development of biaxial fatigue testing of wind turbine blades. During bi-axial fatigue tests, it is necessary to be able to distinguish strains arising from the flapwise motion of the blade from strains arising from the edgewise motion. The method exploits the beam-like structure of blades and is derived using the equations of beam theory. It offers several advantages over the current state of the art method of calibrating strain gauges.

  2. Bend it like Beckham! The Ethics of Genetically Testing Children for Athletic Potential

    PubMed Central

    Camporesi, Silvia

    2016-01-01

    The recent boom of direct-to-consumer (DTC) genetic tests, aimed at measuring children’s athletic potential, is the latest wave in the ‘pre-professionalization’ of children that has characterized, especially but not exclusively, the USA in the last 15 years or so. In this paper, I analyse the use of DTC genetic tests, sometimes coupled with more traditional methods of ‘talent scouting’, to assess a child’s predisposition to athletic performance. I first discuss the scientific evidence at the basis of these tests, and the parental decision in terms of education, and of investing in the children’s future, taken on the basis of the results of the tests. I then discuss how these parental practices impact on the children’s right to an open future, and on their developing sense of autonomy. I also consider the meaning and role of sports in childhood, and conclude that the use of DTC genetic tests to measure children’s athletic potential should be seen as a ‘wake up’ call for other problematic parental attitudes aimed at scouting and developing children’s talent. PMID:27996058

  3. Bend it like Beckham! The Ethics of Genetically Testing Children for Athletic Potential.

    PubMed

    Camporesi, Silvia

    2013-01-01

    The recent boom of direct-to-consumer (DTC) genetic tests, aimed at measuring children's athletic potential, is the latest wave in the 'pre-professionalization' of children that has characterized, especially but not exclusively, the USA in the last 15 years or so. In this paper, I analyse the use of DTC genetic tests, sometimes coupled with more traditional methods of 'talent scouting', to assess a child's predisposition to athletic performance. I first discuss the scientific evidence at the basis of these tests, and the parental decision in terms of education, and of investing in the children's future, taken on the basis of the results of the tests. I then discuss how these parental practices impact on the children's right to an open future, and on their developing sense of autonomy. I also consider the meaning and role of sports in childhood, and conclude that the use of DTC genetic tests to measure children's athletic potential should be seen as a 'wake up' call for other problematic parental attitudes aimed at scouting and developing children's talent.

  4. Effects of microcrack evolution on the electrical resistance of Cu thin films on flexible PI substrates during cyclic-bend testing

    NASA Astrophysics Data System (ADS)

    Bag, Atanu; Park, Ki-Seong; Choi, Shi-Hoon

    2017-07-01

    Cyclic-bend testing was conducted on flexible Cu-clad laminate (FCCL) to investigate the correlation between electrical resistance and the evolution of microcracks. During the test, the change in the electrical resistance of the FCCL was monitored using two-point probe method. The variation in the electrical resistance of the FCCL with respect to the bending cycle can be divided into three stages according to the slope. In order to reveal the microcracks in Cu thin film and how they contribute to the variation in electrical resistance, quantitative analysis of the microcracks was conducted on the surface and cross-section of the deformed Cu thin films using field emission scanning electron microscopy. Analysis showed that the simultaneous extensive evolution of microcracks in the tension and compression zones were main contributors to increase the electrical resistance following specific critical bending cycles.

  5. A novel bending fatigue test device based on self-excited vibration principle and its application to superelastic Nitinol microwire study

    NASA Astrophysics Data System (ADS)

    Leng, Jiaming; Yan, Xiaojun; Zhang, Xiaoyong; Qi, Mingjing; Liu, Zhiwei; Huang, Dawei

    2017-10-01

    Most Nitinol-alloy-based biomedical devices are usually manufactured from straight drawn microwires or microbeams. Fatigue due to cyclic bending is interpreted as the primary failure mechanism in these devices. However, the bending fatigue performance of a Nitinol microwire is rarely studied because of the lack of test devices. Therefore, we firstly establish a bending fatigue test device based on the self-excited vibration principle. Then, we further improve and experimentally verify the device in three aspects to enlarge the strain amplitude: electrode distance optimization, electrode placement angle optimization and local stiffness enhancement. Based on these improvements, the strain amplitude is increased to 6%, successfully meeting the requirements of Nitinol microwire bending fatigue tests. Using the improved test device, a group of superelastic Nitinol (55.8% Ni-44.2% Ti) microwires with a diameter of 50.8 μm are tested. The test results show that the fatigue strain limit for the chosen life (1 × 106 cycles) is around 1.9%, and the inflexion appears at a strain amplitude of 2.3%. SEM observation shows the typical features of low-cycle and high-cycle fatigue on the fracture surfaces.

  6. Experimental Analysis of Mast Lifting and Bending Forces on Vibration Patterns Before and After Pinion Reinstallation in an OH-58 Transmission Test Rig

    NASA Technical Reports Server (NTRS)

    Huff, Edward M.; Lewicki, David G.; Tumer, Irem Y.; Decker, Harry; Barszez, Eric; Zakrajsek, James J.; Norvig, Peter (Technical Monitor)

    2000-01-01

    As part of a collaborative research program between NASA Ames Research Center (ARC), NASA Glenn Research Center (GRC), and the US Army Laboratory, a series of experiments is being performed in GRC's 500 HP OH-58 Transmission Test Rig facility and ARC's AH-I Cobra and OH-58c helicopters. The findings reported in this paper were drawn from Phase-I of a two-phase test-rig experiment, and are focused on the vibration response of an undamaged pinion gear operating in the transmission test rig. To simulate actual flight conditions, the transmission system was run at three torque levels, as well as two mast lifting and two mast bending levels. The test rig was also subjected to disassembly and reassembly of the main pinion housing to simulate the effect of maintenance operations. An analysis of variance based on the total power of the spectral distribution indicates the relative effect of each experimental factor, including Wong interactions with torque. Reinstallation of the main pinion assembly is shown to introduce changes in the vibration signature, suggesting the possibility of a strong effect of maintenance on HUMS design and use. Based on these results, further research will be conducted to compare these vibration responses with actual OH58c helicopter transmission vibration patterns.

  7. Experimental Analysis of Mast Lifting and Bending Forces on Vibration Patterns Before and After Pinion Reinstallation in an OH-58 Transmission Test Rig

    NASA Technical Reports Server (NTRS)

    Huff, Edward M.; Lewicki, David G.; Tumer, Irem Y.; Decker, Harry; Barszez, Eric; Zakrajsek, James J.; Norvig, Peter (Technical Monitor)

    2000-01-01

    As part of a collaborative research program between NASA Ames Research Center (ARC), NASA Glenn Research Center (GRC), and the US Army Laboratory, a series of experiments is being performed in GRC's 500 HP OH-58 Transmission Test Rig facility and ARC's AH-I Cobra and OH-58c helicopters. The findings reported in this paper were drawn from Phase-I of a two-phase test-rig experiment, and are focused on the vibration response of an undamaged pinion gear operating in the transmission test rig. To simulate actual flight conditions, the transmission system was run at three torque levels, as well as two mast lifting and two mast bending levels. The test rig was also subjected to disassembly and reassembly of the main pinion housing to simulate the effect of maintenance operations. An analysis of variance based on the total power of the spectral distribution indicates the relative effect of each experimental factor, including Wong interactions with torque. Reinstallation of the main pinion assembly is shown to introduce changes in the vibration signature, suggesting the possibility of a strong effect of maintenance on HUMS design and use. Based on these results, further research will be conducted to compare these vibration responses with actual OH58c helicopter transmission vibration patterns.

  8. A Biaxial-Bending Test to Observe the Growth of Interacting Delaminations in a Composite Laminate Plate

    NASA Technical Reports Server (NTRS)

    McElroy, Mark; Jackson, Wade; Pankow, Mark

    2016-01-01

    It is not easy to isolate the damage mechanisms associated with low-velocity impact in composites using traditional experiments. In this work, a new experiment is presented with the goal of generating data representative of progressive damage processes caused by low-velocity impact in composite materials. Carbon fiber reinforced polymer test specimens were indented quasi-statically such that a biaxial-bending state of deformation was achieved. As a result, a three-dimensional damage process, involving delamination and delamination-migration, was observed and documented using ultrasonic and x-ray computed tomography. Results from two different layups are presented in this paper. Delaminations occurred at up to three different interfaces and interacted with one another via transverse matrix cracks. Although this damage pattern is much less complex than that of low-velocity impact on a plate, it is more complex than that of a standard delamination coupon test and provides a way to generate delamination, matrix cracking, and delamination-migration in a controlled manner. By limiting the damage process in the experiment to three delaminations, the same damage mechanisms seen during impact could be observed but in a simplified manner. This type of data is useful in stages of model development and validation when the model is capable of simulating simple tests, but not yet capable of simulating more complex and realistic damage scenarios.

  9. Bending properties of different REBCO coated conductor tapes and Roebel cables at T = 77 K

    NASA Astrophysics Data System (ADS)

    Otten, Simon; Kario, Anna; Kling, Andrea; Goldacker, Wilfried

    2016-12-01

    Application of REBCO coated conductors in coils or cables involves deformation of the conductor in different modes, such as in-plane bending, out-of-plane bending and torsion. For example, the dipole magnet designs in the EuCARD-2 project require bending radii as low as 7.5 mm, inducing significant bending strain in the REBCO layer. In this paper, we investigate the effect of out-of-plane bending on the current-carrying properties of coated conductors from different manufacturers. The samples are manipulated by means of a Goldacker-type bending rig, which allows continuous bending at T = 77 K. By reversal to R=∞ after each bending step, the reversible strain effect is separated from irreversible degradation. All tested conductors are found to tolerate compressive bending to a radius of 6 mm with less than 5% irreversible degradation of the critical current. The magnitude of the reversible strain effect shows a large variation among the samples. The effect of out-of-plane bending on Roebel cables is investigated as well, and the results are compared to the bending characteristic of single conductors. The results show no detrimental effect of the cable assembly on the bending properties within the constraints of the test.

  10. Dispersion suppressors with bending

    SciTech Connect

    Garren, A.

    1985-10-01

    Dispersion suppressors of two main types are usually used. In one the cell quadrupole focussing structure is the same as in normal cells but some of the dipoles are replaced by drifts. In the other, the quadrupole strengths and/or spacings are different from those of the normal cells, but the bending is about the same as it is in the cells. In SSC designs to date, dispersion suppressors of the former type have been used, consisting of two cells with bending equivalent to one. In this note a suppressor design with normal bending and altered focussing is presented. The advantage of this scheme is that circumference is reduced. The disadvantages are that additional special quadrupoles must be provided (however, they need not be adjustable), and the maximum beta values within them are about 30% higher than the cell maxima.

  11. On the impact bending test technique for high-strength pipe steels

    NASA Astrophysics Data System (ADS)

    Arsenkin, A. M.; Odesskii, P. D.; Shabalov, I. P.; Likhachev, M. V.

    2015-10-01

    It is shown that the impact toughness (KCV-40 = 250 J/cm2) accepted for pipe steels of strength class K65 (σy ≥ 550 MPa) intended for large-diameter gas line pipes is ineffective to classify steels in fracture strength. The results obtained upon testing of specimens with a fatigue crack and additional sharp lateral grooves seem to be more effective. In energy consumption, a macrorelief with splits is found to be intermediate between ductile fracture and crystalline brittle fracture. A split formation mechanism is considered and a scheme is proposed for split formation.

  12. Stringer Bending Test Helps Diagnose and Prevent Cracks in the Space Shuttle's External Tank

    NASA Technical Reports Server (NTRS)

    Saxon, Joseph B.; Swanson, Gregory R.; Ondocsin, William P.; Wingate, Robert J.

    2012-01-01

    Space Shuttle Discovery's last mission, STS-133, was scheduled to launch on November 5, 2010. Just hours before liftoff, a hydrogen leak at an umbilical connection scrubbed the launch attempt. After the scrub, further inspection revealed a large crack in the foam insulation covering the External Tank, ET-137. Video replay of the launch attempt confirmed the crack first appeared as cryogenic propellants were being loaded into the ET. When the cracked foam was removed, technicians found the underlying stringer had two 9-inch-long cracks. Further inspection revealed a total of 5 of the 108 ET stringers had cracked. NASA and Lockheed Martin immediately launched an aggressive campaign to understand the cracks and repair the stringers in ET-137, targeting February 2011 as the new launch date for STS-133. Responsibilities for the various aspects of the investigation were widely distributed among NASA centers and organizations. This paper will focus on lab testing at Marshall Space Flight Center (MSFC) in Huntsville, Alabama that was intended to replicate the stringer failure and gauge the effect of proposed countermeasures.

  13. Improving the estimate of the effective elastic modulus derived from three-point bending tests of long bones.

    PubMed

    Kourtis, Lampros C; Carter, Dennis R; Beaupre, Gary S

    2014-08-01

    Three-point bending tests are often used to determine the apparent or effective elastic modulus of long bones. The use of beam theory equations to interpret such tests can result in a substantial underestimation of the true effective modulus. In this study three-dimensional, nonlinear finite element analysis is used to quantify the errors inherent in beam theory and to create plots that can be used to correct the elastic modulus calculated from beam theory. Correction plots are generated for long bones representative of a variety of species commonly used in research studies. For a long bone with dimensions comparable to the mouse femur, the majority of the error in the effective elastic modulus results from deformations to the bone cross section that are not accounted for in the equations from beam theory. In some cases, the effective modulus calculated from beam theory can be less than one-third of the true effective modulus. Errors are larger: (1) for bones having short spans relative to bone length; (2) for bones with thin vs. thick cortices relative to periosteal diameter; and (3) when using a small radius or "knife-edge" geometry for the center loading ram and the outer supports in the three-point testing system. The use of these correction plots will enable researchers to compare results for long bones from different animal strains and to compare results obtained using testing systems that differ with regard to length between the outer supports and the radius used for the loading ram and outer supports.

  14. Ultimate bending capacity of strain hardening steel pipes

    NASA Astrophysics Data System (ADS)

    Chen, Yan-fei; Zhang, Juan; Zhang, Hong; Li, Xin; Zhou, Jing; Cao, Jing

    2016-04-01

    Based on Hencky's total strain theory of plasticity, ultimate bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material, the simplified analytical solution is proposed as well. Good agreement is observed when ultimate bending capacities obtained from analytical solutions are compared with experimental results from full-size tests of steel pipes. Parametric study conducted as part of this paper indicates that the strain hardening effect has significant influence on the ultimate bending capacity of steel pipes. It is shown that pipe considering strain hardening yields higher bending capacity than that of pipe assumed as elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the ultimate bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore/onshore steel pipes, supports of offshore platforms and other tubular structural steel members.

  15. Bending strength of shallow glued-laminated beams of a uniform grade

    Treesearch

    Catherine M. Marx; Russell C. Moody

    1981-01-01

    Ninety glued-laminated Douglas-fir or southern pine beams of a uniform grade with 2-, 4-, or 6-laminations were evaluated in static bending tests. No specially graded tension laminations or end joints were used. The purpose of the tests was to determine which of three present design criteria best predict near minimum bending strength values for shallow glued-laminated...

  16. Ares I Static Tests Design

    NASA Technical Reports Server (NTRS)

    Carson, William; Lindemuth, Kathleen; Mich, John; White, K. Preston; Parker, Peter A.

    2009-01-01

    Probabilistic engineering design enhances safety and reduces costs by incorporating risk assessment directly into the design process. In this paper, we assess the format of the quantitative metrics for the vehicle which will replace the Space Shuttle, the Ares I rocket. Specifically, we address the metrics for in-flight measurement error in the vector position of the motor nozzle, dictated by limits on guidance, navigation, and control systems. Analyses include the propagation of error from measured to derived parameters, the time-series of dwell points for the duty cycle during static tests, and commanded versus achieved yaw angle during tests. Based on these analyses, we recommend a probabilistic template for specifying the maximum error in angular displacement and radial offset for the nozzle-position vector. Criteria for evaluating individual tests and risky decisions also are developed.

  17. Design and manufacturing rules for maximizing the performance of polycrystalline piezoelectric bending actuators

    NASA Astrophysics Data System (ADS)

    Jafferis, Noah T.; Smith, Michael J.; Wood, Robert J.

    2015-06-01

    Increasing the energy and power density of piezoelectric actuators is very important for any weight-sensitive application, and is especially crucial for enabling autonomy in micro/milli-scale robots and devices utilizing this technology. This is achieved by maximizing the mechanical flexural strength and electrical dielectric strength through the use of laser-induced melting or polishing, insulating edge coating, and crack-arresting features, combined with features for rigid ground attachments to maximize force output. Manufacturing techniques have also been developed to enable mass customization, in which sheets of material are pre-stacked to form a laminate from which nearly arbitrary planar actuator designs can be fabricated using only laser cutting. These techniques have led to a 70% increase in energy density and an increase in mean lifetime of at least 15× compared to prior manufacturing methods. In addition, measurements have revealed a doubling of the piezoelectric coefficient when operating at the high fields necessary to achieve maximal energy densities, along with an increase in the Young’s modulus at the high compressive strains encountered—these two effects help to explain the higher performance of our actuators as compared to that predicted by linear models.

  18. Optical design and testing: introduction.

    PubMed

    Fang, Yi Chin; Liang, Chao-Wen; Koshel, John; Sasian, Jose; Yatagai, Toyohiko; Wang, Yongtian; Zavisian, James M

    2015-10-01

    Optical design and testing have numerous applications in industrial, military, consumer, and bio-medical settings. This issue features original research ranging from the optical design of image and nonimage optical stimuli for human perception, optics applications, bio-optics applications, displays, and solar energy systems to novel imaging modalities from deep UV to infrared spectral imaging, a systems perspective to imaging, as well as optical measurement. In addition, new concepts and trends for optics and further optical systems will be especially highlighted in this special issue.

  19. Optical design and testing: introduction.

    PubMed

    Liang, Chao-Wen; Koshel, John; Sasian, Jose; Breault, Robert; Wang, Yongtian; Fang, Yi Chin

    2014-10-10

    Optical design and testing has numerous applications in industrial, military, consumer, and medical settings. Assembling a complete imaging or nonimage optical system may require the integration of optics, mechatronics, lighting technology, optimization, ray tracing, aberration analysis, image processing, tolerance compensation, and display rendering. This issue features original research ranging from the optical design of image and nonimage optical stimuli for human perception, optics applications, bio-optics applications, 3D display, solar energy system, opto-mechatronics to novel imaging or nonimage modalities in visible and infrared spectral imaging, modulation transfer function measurement, and innovative interferometry.

  20. Critical current measurement with spatial periodic bending imposed by electromagnetic force on a standard test barrel with slots

    NASA Astrophysics Data System (ADS)

    Nijhuis, A.; Wessel, W. A. J.; Ilyin, Y.; den Ouden, A.; ten Kate, H. H. J.

    2006-05-01

    We have developed and validated a straightforward and fast method to investigate the response of technological superconducting strain sensitive wires (e.g., Nb3Sn) to a spatial periodic bending strain. In the present concept of cabled superconductors for application in nuclear fusion reactors the wires are twisted and cabled in several stages. When subjected to transverse electromagnetic forces after charging the magnet, the individual strands are subjected to spatial periodic bending with wavelengths in the order of 5-10mm. Several apparatuses are presently under development to study the effect of bending on the transport properties, i.e., the voltage-current transition in terms of critical current (Ic) and n value. We propose a supplementary simple method to investigate the influence of bending strain by using a spatial periodic wire support on a broadly used standard Ic measurement barrel in combination with a Lorentz force. The bending force (BI) is varied by changing the applied field B. The peak bending strain in the Nb3Sn filaments is determined by the amplitude of the bending deflection, which is deduced from the mechanical axial tensile stress-strain properties of the wire. Three different spatial periodic wavelengths are applied and the results are in good agreement with the predictions. In addition we found a good agreement with results obtained by a more advanced experiment, named TARSIS, which is described briefly. The "barrel-with-slots" method can be applied easily and straightforward with minor effort and cost in laboratories having a standard Ic measurement facility for superconducting wire.

  1. Critical current measurement with spatial periodic bending imposed by electromagnetic force on a standard test barrel with slots

    SciTech Connect

    Nijhuis, A.; Wessel, W.A.J.; Ilyin, Y.; Ouden, A. den; Kate, H.H.J. ten

    2006-05-15

    We have developed and validated a straightforward and fast method to investigate the response of technological superconducting strain sensitive wires (e.g., Nb{sub 3}Sn) to a spatial periodic bending strain. In the present concept of cabled superconductors for application in nuclear fusion reactors the wires are twisted and cabled in several stages. When subjected to transverse electromagnetic forces after charging the magnet, the individual strands are subjected to spatial periodic bending with wavelengths in the order of 5-10 mm. Several apparatuses are presently under development to study the effect of bending on the transport properties, i.e., the voltage-current transition in terms of critical current (I{sub c}) and n value. We propose a supplementary simple method to investigate the influence of bending strain by using a spatial periodic wire support on a broadly used standard I{sub c} measurement barrel in combination with a Lorentz force. The bending force (BI) is varied by changing the applied field B. The peak bending strain in the Nb{sub 3}Sn filaments is determined by the amplitude of the bending deflection, which is deduced from the mechanical axial tensile stress-strain properties of the wire. Three different spatial periodic wavelengths are applied and the results are in good agreement with the predictions. In addition we found a good agreement with results obtained by a more advanced experiment, named TARSIS, which is described briefly. The 'barrel-with-slots' method can be applied easily and straightforward with minor effort and cost in laboratories having a standard I{sub c} measurement facility for superconducting wire.

  2. Test Method for the Fatigue Life of Layered TiB/Ti Functionally Graded Beams Subjected to Fully Reversed Bending

    NASA Astrophysics Data System (ADS)

    Byrd, Larry; Rickerd, Greg; Wyen, Travis; Cooley, Glenn; Quast, Jeff

    2008-02-01

    Sonic fatigue of aircraft is characterized by fully reversed bending of components subjected to acoustic excitation. This problem is compounded in high temperature environments because solutions for acoustics which tend to result in stiff structures make thermal problems worse. Conversely solutions to the thermal problem which allow expansion often fail in the presence of high acoustic levels. Errors in fatigue life prediction in the combined environment often range from a factor of 4 to 10. This results in either heavy, overly stiff structure or premature failure. This work will test the hypothesis that the fatigue life of a layered functionally graded material (FGM) will be dominated by the failure of the stiffest outer layer. This is based on the observation that for isotropic materials the life is approximately 90% crack initiation and only 10% crack growth before failure. Four sets of cantilever specimens will be tested using an electro-mechanical shaker for base excitation. The excitation will be narrow band random around the fundamental frequency. Two sets of specimens are of uniform composition consisting of 85%TiB/Ti and two are graded specimens consisting of layers that vary from commercially pure titanium to 85%TiB/Ti. Strain vs number of cycles to failure curves will be generated with both constant amplitude sine and narrow band random around the fundamental frequency excitation. The results will be examined to compare life of the uniform material to the functionally graded material. Also to be studied will be the use of Miner's rule to predict the fatigue life of the randomly excited specimens.

  3. Influence of cross-sectional design and dimension on mechanical behavior of nickel-titanium instruments under torsion and bending: a numerical analysis.

    PubMed

    Zhang, En-Wei; Cheung, Gary S P; Zheng, Yu-Feng

    2010-08-01

    The aim of this study was to examine the influence of the cross-sectional configuration and dimensions (size and taper) on the torsional and bending behavior of nickel-titanium rotary instruments, taking into account the nonlinear mechanical properties of material. Ten cross-sectional configurations, square, triangular, U-type, S-type (large and small), convex-triangle, and 4 proprietary ones (Mani NRT and RT2, Quantec, and Mtwo), were analyzed under torsion or bending by using a 3-dimensional finite element method. The von Mises stresses were correlated with the critical values for various phases of the nickel-titanium material. Different loading conditions led to unequal patterns of stress distribution. Increasing the applied torque or bending angle resulted in a rise in the corresponding stresses in the instrument. Favorable stress distribution without dangerous stress concentration was observed if the material was undergoing superelastic transformation at that applied load. The ultimate strength of the material was not exceeded when the instrument was bent up to a 50-degree curvature. On the other hand, when a torsional moment of greater than 1.0 N*mm was applied, the maximum stresses developed in some designs would exceed the ultimate strength of the material. Little variation in the von Mises stresses was observed for instruments of different nominal sizes and tapers on bending to similar extent. The cross-sectional design has a greater impact than taper or size of the instrument on the stresses developed in the instrument under either torsion or bending. Certain cross-sectional configurations are prone to fracture by excess torsional stresses. Copyright 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Performance monitoring of large-scale autonomously healed concrete beams under four-point bending through multiple non-destructive testing methods

    NASA Astrophysics Data System (ADS)

    Karaiskos, G.; Tsangouri, E.; Aggelis, D. G.; Van Tittelboom, K.; De Belie, N.; Van Hemelrijck, D.

    2016-05-01

    Concrete is still the leading structural material due to its low production cost and great structural design flexibility. Although it is distinguished by such a high durability and compressive strength, it is vulnerable in a series of ambient and operational degradation factors which all too frequently result in crack formation that can adversely affect its mechanical performance. The autonomous healing system, using encapsulated polyurethane-based, expansive, healing agent embedded in concrete, is triggered by the crack formation and propagation and promises material repair and operational service life extension. As shown in our previous studies, the formed cracks on small-scale concrete beams are sealed and repaired by filling them with the healing agent. In the present study, the crack formation and propagation in autonomously healed, large-scale concrete beams are thoroughly monitored through a combination of non-destructive testing (NDT) methods. The ultrasonic pulse velocity (UPV), using embedded low-cost and aggregate-size piezoelectric transducers, the acoustic emission (AE) and the digital image correlation (DIC) are the NDT methods which are comprehensively used. The integrated ultrasonic, acoustic and optical monitoring system introduces an experimental configuration that detects and locates the four-point bending mode fracture on large-scale concrete beams, detects the healing activation process and evaluates the subsequent concrete repair.

  5. Engineering test facility design definition

    NASA Technical Reports Server (NTRS)

    Bercaw, R. W.; Seikel, G. R.

    1980-01-01

    The Engineering Test Facility (ETF) is the major focus of the Department of Energy (DOE) Magnetohydrodynamics (MHD) Program to facilitate commercialization and to demonstrate the commercial operability of MHD/steam electric power. The ETF will be a fully integrated commercial prototype MHD power plant with a nominal output of 200 MW sub e. Performance of this plant is expected to meet or surpass existing utility standards for fuel, maintenance, and operating costs; plant availability; load following; safety; and durability. It is expected to meet all applicable environmental regulations. The current design concept conforming to the general definition, the basis for its selection, and the process which will be followed in further defining and updating the conceptual design.

  6. Bend ductility of tungsten heavy alloys

    SciTech Connect

    Gurwell, W.E.; Garnich, M.R.; Dudder, G.B.; Lavender, C.A.

    1992-11-01

    A bend ductility test is used to indicate the formability of tungsten heavy alloys sheet. The primary test bends a notchless Charpy impact specimen to a bend angle of approximately 100C. This can be augmented by a bend-completion test. Finite element modeling as well as strain-gaged bend specimens elucidate the strain distribution in the specimen as a function of material thickness and bend angle. The bend ductilities of 70%W, 807.W and 90%W alloys are characterized. As expected, decreasing thickness or tungsten content enhances bend ductility. Oxidation is not detrimental; therefore, controlled atmosphere is not required for cooling. The potentially detrimental effects of mechanical working (e.g., rolling, roller-leveling, grit blasting, and peening) and machining (e.g., cutting and sanding) are illustrated.

  7. Bend ductility of tungsten heavy alloys

    SciTech Connect

    Gurwell, W.E.; Garnich, M.R.; Dudder, G.B.; Lavender, C.A.

    1992-11-01

    A bend ductility test is used to indicate the formability of tungsten heavy alloys sheet. The primary test bends a notchless Charpy impact specimen to a bend angle of approximately 100C. This can be augmented by a bend-completion test. Finite element modeling as well as strain-gaged bend specimens elucidate the strain distribution in the specimen as a function of material thickness and bend angle. The bend ductilities of 70%W, 807.W and 90%W alloys are characterized. As expected, decreasing thickness or tungsten content enhances bend ductility. Oxidation is not detrimental; therefore, controlled atmosphere is not required for cooling. The potentially detrimental effects of mechanical working (e.g., rolling, roller-leveling, grit blasting, and peening) and machining (e.g., cutting and sanding) are illustrated.

  8. In vivo measurements of human bone deformation using optical segment tracking: surgical approach and validation in a three-point bending test.

    PubMed

    Ganse, B; Yang, P-F; Brüggemann, G-P; Müller, L P; Rittweger, J; Koy, T

    2014-03-01

    The purpose of the study was to validate optical segment tracking, a new method for in vivo human tibia deformation measurements and to assess bending in a three-point bending test. The approach relies upon optical motion capturing of reflecting marker clusters affixed to the bone via screws inserted three millimeters into the corticalis in local anesthesia. The method was tested in five healthy subjects. Screws were left in place for six to eight hours and a variety of exercises performed. A pain questionnaire was used to assess pain levels. PQCT-images were taken to locate screw holes in the bone. A three-point bending test was performed and repeatability evaluated. The new method shows good feasibility though this was previously considered impossible by many experts. Local anesthesia works for screw implantation and explantation. Results show linearity with an average of 0.25 degrees per 10 kg of weight applied with good repeatability (average variation coefficient 8%). Optical segment tracking is feasible for human in vivo bone deformation measurements. There is a variety of possible clinical and experimental applications including stability testing of osteosyntheses and joints, monitoring of bone healing, evaluation of exercises in physiotherapy, and assessment of bone deformation patterns in bone disease.

  9. Finding line of action of the force exerted on erect spine based on lateral bending test in personalization of scoliotic spine models.

    PubMed

    Jalalian, Athena; Tay, Francis Eng Hock; Arastehfar, Soheil; Gibson, Ian; Liu, Gabriel

    2017-04-01

    In multi-body models of scoliotic spine, personalization of mechanical properties of joints significantly improves reconstruction of the spine shape. In personalization methods based on lateral bending test, simulation of bending positions is an essential step. To simulate, a force is exerted on the spine model in the erect position. The line of action of the force affects the moment of the force about the joints and thus, if not correctly identified, causes over/underestimation of mechanical properties. Therefore, we aimed to identify the line of action, which has got little attention in previous studies. An in-depth analysis was performed on the scoliotic spine movement from the erect to four spine positions in the frontal plane by using pre-operative X-rays of 18 adolescent idiopathic scoliosis (AIS) patients. To study the movement, the spine curvature was considered as a 2D chain of micro-scale motion segments (MMSs) comprising rigid links and 1-degree-of-freedom (DOF) rotary joints. It was found that two MMSs representing the inflection points of the erect spine had almost no rotation (0.0028° ± 0.0021°) in the movement. The small rotation can be justified by weak moment of the force about these MMSs due to very small moment arm. Therefore, in the frontal plane, the line of action of the force to simulate the left/right bending position was defined as the line that passes through these MMSs in the left/right bending position. Through personalization of a 3D spine model for our patients, we demonstrated that our line of action could result in good estimates of the spine shape in the bending positions and other positions not included in the personalization, supporting our proposed line of action.

  10. Beam bending via plasmonic lenses.

    PubMed

    Zhao, Yanhui; Lin, Sz-Chin Steven; Nawaz, Ahmad Ahsan; Kiraly, Brian; Hao, Qingzhen; Liu, Yanjun; Huang, Tony Jun

    2010-10-25

    We have designed and characterized three different types of plasmonic lenses that cannot only focus, but can also bend electromagnetic (EM) waves. The bending effect is achieved by constructing an asymmetric phase front caused by varying phase retardations in EM waves as they pass through a plasmonic lens. With an incident wave normal to the lens surface, light bends up to 8° off the axial direction. The optical wave propagation was numerically investigated using the finite-difference time-domain (FDTD) method. Simulation results show that the proposed plasmonic lenses allow effective beam bending under both normal and tilted incidence. With their relatively large bending range and capability to perform in the far field, the plamsonic lenses described in this article could be valuable in applications such as photonic communication and plasmonic circuits.

  11. Biomechanical properties of the mid-shaft femur in middle-aged hypophysectomized rats as assessed by bending test.

    PubMed

    Bozzini, Clarisa; Picasso, Emilio O; Champin, Graciela M; Alippi, Rosa María; Bozzini, Carlos E

    2012-10-01

    Both stiffness and strength of bones are thought to be controlled by the "bone mechanostat". Its natural stimuli would be the strains of bone tissue (sensed by osteocytes) that are induced by both gravitational forces (body weight) and contraction of regional muscles. Body weight and muscle mass increase with age. Biomechanical performance of load-bearing bones must adapt to these growth-induced changes. Hypophysectomy in the rat slows the rate of body growth. With time, a great difference in body size is established between a hypophysectomized rat and its age-matched control, which makes it difficult to establish the real effect of pituitary ablation on bone biomechanics. The purpose of the present investigation was to compare mid-shaft femoral mechanical properties between hypophysectomized and weight-matched normal rats, which will show similar sizes and thus will be exposed to similar habitual loads. Two groups of 10 female rats each (H and C) were established. H rats were 12-month-old that had been hypophysectomized 11 months before. C rats were 2.5-month-old normals. Right femur mechanical properties were tested in 3-point bending. Structural (load-bearing capacity and stiffness), geometric (cross-sectional area, cortical sectional area, and moment of inertia), and material (modulus of elasticity and maximum elastic stress) properties were evaluated. The left femur was ashed for calcium content. Comparisons between parameters were performed by the Student's t test. Average body weight, body length, femur weight, femur length, and gastrocnemius weight were not significantly different between H and C rats. Calcium content in ashes was significantly higher in H than in C rats. Cross-sectional area, medullary area, and cross-sectional moment of inertia were higher in C rats, whereas cortical area did not differ between groups. Structural properties (diaphyseal stiffness, elastic limit, and load at fracture) were about four times higher in hypophysectomized rats

  12. Designing Test Chips for Custom Integrated Circuits

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Griswold, T. W.; Pina, C. A.; Timoc, C. C.

    1985-01-01

    Collection of design and testing procedures partly automates development of built-in test chips for CMOS integrated circuits. Testchip methodology intended especially for users of custom integratedcircuit wafers. Test-Chip Designs and Testing Procedures (including datareduction procedures) generated automatically by computer from programed design and testing rules and from information supplied by user.

  13. Bend-insensitive optical fibers for FTTH applications

    NASA Astrophysics Data System (ADS)

    Li, Ming-Jun

    2009-01-01

    This paper reviews recent development in bend-insensitive fibers for fiber-to-the-home (FTTH) applications. First, requirements for bend-insensitive fibers are discussed. Then different design approaches for reducing fiber bending loss are described and compared. A new bend-insensitive fiber using the nano-engineered ring design is presented in detail.

  14. Design, tests and commissioning of the EMMA injection septum

    NASA Astrophysics Data System (ADS)

    Marinov, K.; Clarke, J. A.; Marks, N.; Tzenov, S.

    2013-02-01

    The paper describes the main steps taken during the design and commissioning stages of the EMMA injection and extraction septum magnets. A preliminary analysis of the problem is presented first followed by a discussion of the results obtained through finite element magnetic modeling and design optimization. The measures taken to suppress the stray field generated by the magnet are discussed in detail. Two sets of tests are performed on the magnet: magnetic field measurement resulting in a three-dimensional magnetic field map and measurement of the electron beam bending angle as a function of the magnet current. The values of the effective magnetic length resulting from the two sets of measurement are found to be in excellent agreement.

  15. Design and test of a squeeze-film damper for a flexible power transmission shaft

    NASA Technical Reports Server (NTRS)

    Darlow, M. S.; Smalley, A. J.

    1978-01-01

    For a flexible shaft designed to pass through a number of bending critical speeds, a squeeze-film damper has been designed and tested. The damper properties were selected to provide control of all critical speeds, while meeting additional constraints of high power transmission requirements and damper simplicity. The damper was fabricated and installed and its ability to control flexible shaft vibrations was demonstrated by the comparison of vibration amplitudes both with and without the damper.

  16. Design and test of a squeeze-film damper for a flexible power transmission shaft

    NASA Technical Reports Server (NTRS)

    Darlow, M. S.; Smalley, A. J.

    1978-01-01

    For a flexible shaft designed to pass through a number of bending critical speeds, a squeeze-film damper has been designed and tested. The damper properties were selected to provide control of all critical speeds, while meeting additional constraints of high power transmission requirements and damper simplicity. The damper was fabricated and installed and its ability to control flexible shaft vibrations was demonstrated by the comparison of vibration amplitudes both with and without the damper.

  17. Bending rules for animal propulsion.

    PubMed

    Lucas, Kelsey N; Johnson, Nathan; Beaulieu, Wesley T; Cathcart, Eric; Tirrell, Gregory; Colin, Sean P; Gemmell, Brad J; Dabiri, John O; Costello, John H

    2014-01-01

    Animal propulsors such as wings and fins bend during motion and these bending patterns are believed to contribute to the high efficiency of animal movements compared with those of man-made designs. However, efforts to implement flexible designs have been met with contradictory performance results. Consequently, there is no clear understanding of the role played by propulsor flexibility or, more fundamentally, how flexible propulsors should be designed for optimal performance. Here we demonstrate that during steady-state motion by a wide range of animals, from fruit flies to humpback whales, operating in either air or water, natural propulsors bend in similar ways within a highly predictable range of characteristic motions. By providing empirical design criteria derived from natural propulsors that have convergently arrived at a limited design space, these results provide a new framework from which to understand and design flexible propulsors.

  18. Design considerations and test facilities for accelerated radiation effects testing

    NASA Technical Reports Server (NTRS)

    Price, W. E.; Miller, C. G.; Parker, R. H.

    1972-01-01

    Test design parameters for accelerated dose rate radiation effects tests for spacecraft parts and subsystems used in long term mission (years) are detailed. A facility for use in long term accelerated and unaccelerated testing is described.

  19. Item Calibration in Incomplete Testing Designs

    ERIC Educational Resources Information Center

    Eggen, Theo J. H. M.; Verhelst, Norman D.

    2011-01-01

    This study discusses the justifiability of item parameter estimation in incomplete testing designs in item response theory. Marginal maximum likelihood (MML) as well as conditional maximum likelihood (CML) procedures are considered in three commonly used incomplete designs: random incomplete, multistage testing and targeted testing designs.…

  20. Aerosol deposition in bends with turbulent flow

    SciTech Connect

    McFarland, A.R.; Gong, H.; Wente, W.B.

    1997-08-01

    The losses of aerosol particles in bends were determined numerically for a broad range of design and operational conditions. Experimental data were used to check the validity of the numerical model, where the latter employs a commercially available computational fluid dynamics code for characterizing the fluid flow field and Lagrangian particle tracking technique for characterizing aerosol losses. Physical experiments have been conducted to examine the effect of curvature ratio and distortion of the cross section of bends. If it curvature ratio ({delta} = R/a) is greater than about 4, it has little effect on deposition, which is in contrast with the recommendation given in ANSI N13.1-1969 for a minimum curvature ratio of 10. Also, experimental results show that if the tube cross section is flattened by 25% or less, the flattening also has little effect on deposition. Results of numerical tests have been used to develop a correlation of aerosol penetration through a bend as a function of Stokes number (Stk), curvature ratio ({delta}) and the bend angle ({theta}). 17 refs., 10 figs., 2 tabs.

  1. Program Helps Design Tests Of Developmental Software

    NASA Technical Reports Server (NTRS)

    Hops, Jonathan

    1994-01-01

    Computer program called "A Formal Test Representation Language and Tool for Functional Test Designs" (TRL) provides automatic software tool and formal language used to implement category-partition method and produce specification of test cases in testing phase of development of software. Category-partition method useful in defining input, outputs, and purpose of test-design phase of development and combines benefits of choosing normal cases having error-exposing properties. Traceability maintained quite easily by creating test design for each objective in test plan. Effort to transform test cases into procedures simplified by use of automatic software tool to create cases based on test design. Method enables rapid elimination of undesired test cases from consideration and facilitates review of test designs by peer groups. Written in C language.

  2. Sheet Bending using Soft Tools

    NASA Astrophysics Data System (ADS)

    Sinke, J.

    2011-05-01

    Sheet bending is usually performed by air bending and V-die bending processes. Both processes apply rigid tools. These solid tools facilitate the generation of software for the numerical control of those processes. When the lower rigid die is replaced with a soft or rubber tool, the numerical control becomes much more difficult, since the soft tool deforms too. Compared to other bending processes the rubber backed bending process has some distinct advantages, like large radius-to-thickness ratios, applicability to materials with topcoats, well defined radii, and the feasibility of forming details (ridges, beads). These advantages may give the process exclusive benefits over conventional bending processes, not only for industries related to mechanical engineering and sheet metal forming, but also for other disciplines like Architecture and Industrial Design The largest disadvantage is that also the soft (rubber) tool deforms. Although the tool deformation is elastic and recovers after each process cycle, the applied force during bending is related to the deformation of the metal sheet and the deformation of the rubber. The deformation of the rubber interacts with the process but also with sheet parameters. This makes the numerical control of the process much more complicated. This paper presents a model for the bending of sheet materials using a rubber lower die. This model can be implemented in software in order to control the bending process numerically. The model itself is based on numerical and experimental research. In this research a number of variables related to the tooling and the material have been evaluated. The numerical part of the research was used to investigate the influence of the features of the soft lower tool, like the hardness and dimensions, and the influence of the sheet thickness, which also interacts with the soft tool deformation. The experimental research was focused on the relation between the machine control parameters and the most

  3. Dynamic testing for shuttle design verification

    NASA Technical Reports Server (NTRS)

    Green, C. E.; Leadbetter, S. A.; Rheinfurth, M. H.

    1972-01-01

    Space shuttle design verification requires dynamic data from full scale structural component and assembly tests. Wind tunnel and other scaled model tests are also required early in the development program to support the analytical models used in design verification. Presented is a design philosophy based on mathematical modeling of the structural system strongly supported by a comprehensive test program; some of the types of required tests are outlined.

  4. Designing special test instruments for preventive maintenance.

    PubMed

    McCullough, C E; Baker, L S

    1979-01-01

    Periodic performance testing of biomedical equipment can be made considerably more efficient by careful design of test procedures and by fabrication of special test instruments which are designed for those procedures. The design philosophy behind such procedures and instruments and its applicability to a wide variety of biomedical devices is discussed. As a practical example, an ECG machine/patient monitor test system is described and construction details are given.

  5. An Experimental Investigation of Transverse Tension Fatigue Characterization of IM6/3501-6 Composite Materials Using a Three-Point Bend Test

    NASA Technical Reports Server (NTRS)

    Peck, Ann W.

    1998-01-01

    As composites are introduced into more complex structures with out-of-plane loadings, a better understanding is needed of the out-of-plane, matrix-dominated failure mechanisms. This work investigates the transverse tension fatigue characteristics of IM6/3501 composite materials. To test the 90 degree laminae, a three-point bend test was chosen, potentially minimizing handling and gripping issues associated with tension tests. A finite element analysis was performed of a particular specimen configuration to investigate the influence of specimen size on the stress distribution for a three-point bend test. Static testing of 50 specimens of 9 different sized configurations produced a mean transverse tensile strength of 61.3 Mpa (8.0 ksi). The smallest configuration (10.2 mm wide, Span-to-thickness ratio of 3) consistently exhibited transverse tensile failures. A volume scale effect was difficult to discern due to the large scatter of the data. Static testing of 10 different specimens taken from a second panel produced a mean transverse tensile strength of 82.7 Mpa (12.0 ksi). Weibull parameterization of the data was possible, but due to variability in raw material and/or manufacturing, more replicates are needed for greater confidence. Three-point flex fatigue testing of the smallest configuration was performed on 59 specimens at various levels of the mean static transverse tensile strength using an R ratio of 0.1 and a frequency of 20 Hz. A great deal of scatter was seen in the data. The majority of specimens failed near the center loading roller. To determine whether the scatter in the fatigue data is due to variability in raw material and/or the manufacturing process, additional testing should be performed on panels manufactured from different sources.

  6. A3 Subscale Diffuser Test Article Design

    NASA Technical Reports Server (NTRS)

    Saunders, G. P.

    2009-01-01

    This paper gives a detailed description of the design of the A3 Subscale Diffuser Test (SDT) Article Design. The subscale diffuser is a geometrically accurate scale model of the A3 altitude rocket facility. It was designed and built to support the SDT risk mitigation project located at the E3 facility at Stennis Space Center, MS (SSC) supporting the design and construction of the A3 facility at SSC. The subscale test article is outfitted with a large array of instrumentation to support the design verification of the A3 facility. The mechanical design of the subscale diffuser and test instrumentation are described here

  7. Contemporary optical instrument design, fabrication and testing

    SciTech Connect

    Beckmann, L.H.J.F.; Briers, J.D.; Yodev, P.R.

    1986-01-01

    These proceedings consist of papers divided between the following sessions: Integration of the design into the system, Fabrication and testing techniques, and Contemporary Optical Instrumentation. Some of the titles are: Optical replication: an overview and design guide for the systems engineer, Fabrication and testing of highly nonconventional optics, Narcissus, a testing tool, and Automatic gauge block measurement using multiple wavelength interferometry.

  8. Limited Associations between Keel Bone Damage and Bone Properties Measured with Computer Tomography, Three-Point Bending Test, and Analysis of Minerals in Swiss Laying Hens

    PubMed Central

    Gebhardt-Henrich, Sabine G.; Pfulg, Andreas; Fröhlich, Ernst K. F.; Käppeli, Susanna; Guggisberg, Dominik; Liesegang, Annette; Stoffel, Michael H.

    2017-01-01

    Keel bone damage is a wide-spread welfare problem in laying hens. It is unclear so far whether bone quality relates to keel bone damage. The goal of the present study was to detect possible associations between keel bone damage and bone properties of intact and damaged keel bones and of tibias in end-of-lay hens raised in loose housing systems. Bones were palpated and examined by peripheral quantitative computer tomography (PQCT), a three-point bending test, and analyses of bone ash. Contrary to our expectations, PQCT revealed higher cortical and trabecular contents in fractured than in intact keel bones. This might be due to structural bone repair after fractures. Density measurements of cortical and trabecular tissues of keel bones did not differ between individuals with and without fractures. In the three-point bending test of the tibias, ultimate shear strength was significantly higher in birds with intact vs. fractured keel bones. Likewise, birds with intact or slightly deviated keel bones had higher mineral and calcium contents of the keel bone than birds with fractured keel bones. Calcium content in keel bones was correlated with calcium content in tibias. Although there were some associations between bone traits related to bone strength and keel bone damage, other factors such as stochastic events related to housing such as falls and collisions seem to be at least as important for the prevalence of keel bone damage. PMID:28848740

  9. Design and Testing of Suit Regulator Test Rigs

    NASA Technical Reports Server (NTRS)

    Campbell, Colin

    2010-01-01

    The next generation space suit requires additional capabilities for controlling and adjusting internal pressure compared to that of historical designs. Next generation suit pressures will range from slight pressure, for astronaut prebreathe comfort, to hyperbaric pressure levels for emergency medical treatment of decompression sickness. In order to test these regulators through-out their development life cycle, novel automated test rigs are being developed. This paper addresses the design philosophy, performance requirements, physical implementation, and test results with various units under test.

  10. Variations in epidural catheter manufacture: implications for bending and stiffness.

    PubMed

    Eckmann, David M

    2003-01-01

    There is no formal evaluation method used to relate epidural catheter design and manufacture to clinical outcomes, such as subarachnoid or intravascular catheter placement. We analyzed catheter bending stiffness to determine the range of stiffness of catheters commonly used. We hypothesized that catheter material has a greater influence on stiffness than does cross-sectional shape. We determined the elastic modulus by axial load testing and the area moment of inertia using calibrated microscopic measurements of cross-sectional geometry for 6 different catheter types, including 2 types of wire styletted catheters. We calculated bending stiffness as the product of the elastic modulus and the area moment of inertia. Catheters had similar area moments of inertia, but markedly different elastic moduli. Nylon and polyurethane catheters had the same bending stiffness, which was twice as high as that of coil reinforced catheters (P <.05), but 35% lower than that of radiopaque catheters (P <.05). Nylon and radiopaque wire styletted catheters had similar bending stiffness, which were 23-fold to 90-fold greater than that of the nonstyletted catheters (P <.05). Catheters currently available establish the range of bending stiffness that should not be exceeded, only optimized to clinical outcome. Clinical studies are needed to correlate the incidence of unintentional intravascular or subarachnoid catheter placement or migration and bending stiffness. Catheter technology improvements may enhance safety and increase the likelihood of successful catheter insertion, maintenance, and removal.

  11. Thermal Oscar Design Test Report and Prototype

    DTIC Science & Technology

    2010-09-01

    1 UNCLAS | CG-926 RDC | D. Decker | Public | Sep 2010 Thermal Oscar Design Test Report and Prototype Distribution Statement...A: Approved for public release; distribution is unlimited. September 2010 Report No: CG-D-05-11 Thermal Oscar Design Test Report and Prototype...06320 Thermal Oscar Design Test Report and Prototype iii UNCLAS | CG-926 RDC | D. Decker | Public | Sep 2010 Technical Report

  12. Metrology and Tests beamline at SOLEIL Design and first results

    SciTech Connect

    Idir, Mourad; Mercere, Pascal; Moreno, Thierry; Delmotte, Aurelien; Dasilva, Paulo; Modi, Mohammed H.

    2010-06-23

    The objectives of this project is install at the 2.75 GeV SOLEIL synchrotron radiation source a calibration and metrology test facility for the R and D of optical components and detectors. We have build, on a bending magnet, two branches to cover an energy range from few eV to 28 keV and give access to white beam. This installation will first address the needs of the SOLEIL experimental groups(Optics and Detectors)and will be used by a large community. This beamline will also be valuable as a general-purpose beamline to prepare, test and set up a wide range of experiments in the field of Astrophysics, laser plasma etc...A complementary important aspect of this installation is the realization of primary standard: the metrology beamline of SOLEIL could become the national primary standard source in collaboration with the Laboratoire National d'Essais(LNE)and help in the design and characterization of several diagnostics for the Megajoule Laser in Bordeaux in collaboration with the CEA DIF. The beamline has been designed to provide great flexibility. In this paper, we describe the beamline design, the end station instrumentation and give also some preliminary results.

  13. Arbitrary angle waveguide bends based on zero-index metamaterials

    NASA Astrophysics Data System (ADS)

    Li, Y. H.; Zhang, L. H.; Chen, Y. Q.; Feng, T. H.; Jiang, H. T.; Chen, H.

    2014-08-01

    In this paper, efficient arbitrary angle bends based on impedance-matched zero-index metamaterials (ZIMs) are proposed. Numerical simulations on ZIM-based bends are carried out in waveguide systems. The results show clearly that electromagnetic waves can tunnel through the ZIM-based bends with high transmittance at any bending angles. Moreover, a realistic ZIM-based bends are designed and fabricated on microstrip transmission line. Both simulated and experimental results confirm well the low loss and arbitrary angle bending effects in a system hiring ZIM-based microstrip ring resonator as bending corners.

  14. Bend Properties of Sapphire Fibers at Elevated Temperatures. 1; Bend Survivability

    NASA Technical Reports Server (NTRS)

    Morscher, Gregory N.; Sayir, Haluk

    1995-01-01

    The effect of temperature on the bend radius that a c-axis-oriented sapphire fiber can withstand was determined for fibers of various diameter. Bend stress rupture tests were performed for times of 1-100 h and temperatures of 300-1700 C. Fibers would survive the bend test undeformed, would fracture or would deform. The bend survival radius was determined to be the radius above which no fibers fractured or deformed for a given time-temperature treatment. It was found that the ability of fibers to withstand curvature decreases substantially with time and increasing temperature and that fibers of smaller diameter (46-83 micron) withstood smaller bend radii than would be expected from just a difference in fiber diameter when compared with the bend results of the fibers of large diameter (144 micron). This was probably due to different flaw populations, causing high temperature bend failure for the tested sapphire fibers of different diameters.

  15. Ovalization of Tubes Under Bending and Compression

    NASA Technical Reports Server (NTRS)

    Demer, L J; Kavanaugh, E S

    1944-01-01

    An empirical equation has been developed that gives the approximate amount of ovalization for tubes under bending loads. Tests were made on tubes in the d/t range from 6 to 14, the latter d/t ratio being in the normal landing gear range. Within the range of the series of tests conducted, the increase in ovalization due to a compression load in combination with a bending load was very small. The bending load, being the principal factor in producing the ovalization, is a rather complex function of the bending moment, d/t ratio, cantilever length, and distance between opposite bearing faces. (author)

  16. Formal functional test designs with a test representation language

    NASA Technical Reports Server (NTRS)

    Hops, J. M.

    1993-01-01

    The application of the category-partition method to the test design phase of hardware, software, or system test development is discussed. The method provides a formal framework for reducing the total number of possible test cases to a minimum logical subset for effective testing. An automatic tool and a formal language were developed to implement the method and produce the specification of test cases.

  17. Design, manufacture and test of the composite case for ERINT-1 solid rocket motor

    NASA Astrophysics Data System (ADS)

    Mard, Francis

    1993-06-01

    SEP is in charge since 1989 of the ERINT-1 motor case and nozzle. The stringent missile weight and volume requirements coupled with the specification to provide an aerodynamically stable configuration over a very large Mach number range led to the need to develop a high-performance composite motor case. Development of this SRM case presented a variety of technical challenges that were solved by an original design: (1) integral skirts, high bending stiffness, and bending loads are required; (2) high temperature composite stiffness and loads are required up to 160 C; (3) integral fin lugs attachments high aerodynamic loading is required on fin lugs; (4) enclosed fore dome; and (5) aft-pinned joint: a large rear opening is required to cast the propellant. Structural testing in ultimate conditions confirmed the soundness of the design. Positive safety margins were demonstrated on both internal pressure and mechanical loads requirements.

  18. 10 CFR 63.133 - Design testing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Design testing. 63.133 Section 63.133 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Performance Confirmation Program § 63.133 Design testing. (a) During the early...

  19. 10 CFR 63.133 - Design testing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Design testing. 63.133 Section 63.133 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Performance Confirmation Program § 63.133 Design testing. (a) During the early or...

  20. 10 CFR 63.133 - Design testing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 2 2013-01-01 2013-01-01 false Design testing. 63.133 Section 63.133 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Performance Confirmation Program § 63.133 Design testing. (a) During the early or...

  1. 10 CFR 63.133 - Design testing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 2 2012-01-01 2012-01-01 false Design testing. 63.133 Section 63.133 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Performance Confirmation Program § 63.133 Design testing. (a) During the early or...

  2. 10 CFR 63.133 - Design testing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Design testing. 63.133 Section 63.133 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN A GEOLOGIC REPOSITORY AT YUCCA MOUNTAIN, NEVADA Performance Confirmation Program § 63.133 Design testing. (a) During the early or...

  3. 10 CFR 60.142 - Design testing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 2 2011-01-01 2011-01-01 false Design testing. 60.142 Section 60.142 Energy NUCLEAR... Performance Confirmation Program § 60.142 Design testing. (a) During the early or developmental stages of... thermal interaction effects of the waste packages, backfill, rock, and groundwater shall be conducted....

  4. 10 CFR 60.142 - Design testing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Design testing. 60.142 Section 60.142 Energy NUCLEAR... Performance Confirmation Program § 60.142 Design testing. (a) During the early or developmental stages of... thermal interaction effects of the waste packages, backfill, rock, and groundwater shall be conducted....

  5. Formal Functional Test Designs: Bridging the Gap Between Test Requirements and Test Specifications

    NASA Technical Reports Server (NTRS)

    Hops, Jonathan

    1993-01-01

    This presentation describes the testing life cycle, the purpose of the test design phase, and test design methods and gives an example application. Also included is a description of Test Representation Language (TRL), a summary of the language, and an example of an application of TRL. A sample test requirement and sample test design are included.

  6. Conducting distributed exercises: coordinated design and testing

    NASA Astrophysics Data System (ADS)

    Sottilare, Robert A.

    1995-06-01

    This paper provides a basis for planning, designing, and testing distributed exercises and experiments. Lessons learned from the Synthetic Theater of War--Europe (STOW-E) exercise conducted in November 1994 are incorporated to provide system engineers/integrators areas of consideration in the design and testing of distributed interactive simulation (DIS) exercises and experiments. Issues involving DIS compliance in accordance with IEEE 1278.1, and interoperability and compatibility testing measures are also discussed. Design and test issues for live, virtual, and constructive simulations are considered. This paper assumes basic knowledge of DIS principles.

  7. Conceptual design of ECLSS microgravity test beds

    NASA Technical Reports Server (NTRS)

    Kolodney, Matt; Dall-Bauman, Liese

    1992-01-01

    Conceptual designs were prepared for Space Station Freedom ECLSS test beds for both the Air Revitalization Subsystem (ARS) and the Water Recovery and Management Subsystem (WRMS), which will allow extended testing of equipment under microgravity conditions. The separate designs for the ARS and the WRMS include storage tanks, plumbing, and limited instrumentation that would be expected to be common to all air or water treatment equipment of interest. The beds are designed to recycle process fluids to the greatest extent possible, thus minimizing the spacecraft/test bed interface requirements. Schematic diagrams of both the ARS and the WRMS test beds are included.

  8. A powerful test for Balaam's design.

    PubMed

    Mori, Joji; Kano, Yutaka

    2015-01-01

    The crossover trial design (AB/BA design) is often used to compare the effects of two treatments in medical science because it performs within-subject comparisons, which increase the precision of a treatment effect (i.e., a between-treatment difference). However, the AB/BA design cannot be applied in the presence of carryover effects and/or treatments-by-period interaction. In such cases, Balaam's design is a more suitable choice. Unlike the AB/BA design, Balaam's design inflates the variance of an estimate of the treatment effect, thereby reducing the statistical power of tests. This is a serious drawback of the design. Although the variance of parameter estimators in Balaam's design has been extensively studied, the estimators of the treatment effect to improve the inference have received little attention. If the estimate of the treatment effect is obtained by solving the mixed model equations, the AA and BB sequences are excluded from the estimation process. In this study, we develop a new estimator of the treatment effect and a new test statistic using the estimator. The aim is to improve the statistical inference in Balaam's design. Simulation studies indicate that the type I error of the proposed test is well controlled, and that the test is more powerful and has more suitable characteristics than other existing tests when interactions are substantial. The proposed test is also applied to analyze a real dataset.

  9. Compaction managed mirror bend achromat

    DOEpatents

    Douglas, David [Yorktown, VA

    2005-10-18

    A method for controlling the momentum compaction in a beam of charged particles. The method includes a compaction-managed mirror bend achromat (CMMBA) that provides a beamline design that retains the large momentum acceptance of a conventional mirror bend achromat. The CMMBA also provides the ability to tailor the system momentum compaction spectrum as desired for specific applications. The CMMBA enables magnetostatic management of the longitudinal phase space in Energy Recovery Linacs (ERLs) thereby alleviating the need for harmonic linearization of the RF waveform.

  10. Investigation of span-chordwise bending anisotropy of honeybee forewings

    PubMed Central

    Ning, JianGuo; Ma, Yun; Zhang, PengFei

    2017-01-01

    ABSTRACT In this study, the spanwise and chordwise bending stiffness EI of honeybee forewings were measured by a cantilevered bending test. The test results indicate that the spanwise EI of the forewing is two orders of magnitude larger than the chordwise EI. Three structural aspects result in this span-chordwise bending anisotropy: the distribution of resilin patches, the corrugation along the span and the leading edge vein of the venation. It was found that flexion lines formed by resilin patches revealed through fluorescence microscopy promoted the chordwise bending of the forewing during flapping flight. Furthermore, the corrugation of the wing and leading edge veins of the venation, revealed by micro-computed tomography, determines the relatively greater spanwise EI of the forewing. The span-chordwise anisotropy exerts positive structural and aerodynamic influences on the wing. In summary, this study potentially assists researchers in understanding the bending characteristics of insect wings and might be an important reference for the design and manufacture of bio-inspired wings for flapping micro aerial vehicles. PMID:28396486

  11. Quasi-Static 3-Point Reinforced Carbon-Carbon Bend Test and Analysis for Shuttle Orbiter Wing Leading Edge Impact Damage Thresholds

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Sotiris, Kellas

    2006-01-01

    Static 3-point bend tests of Reinforced Carbon-Carbon (RCC) were conducted to failure to provide data for additional validation of an LS-DYNA RCC model suitable for predicting the threshold of impact damage to shuttle orbiter wing leading edges. LS-DYNA predictions correlated well with the average RCC failure load, and were good in matching the load vs. deflection. However, correlating the detectable damage using NDE methods with the cumulative damage parameter in LS-DYNA material model 58 was not readily achievable. The difficulty of finding internal RCC damage with NDE and the high sensitivity of the mat58 damage parameter to the load near failure made the task very challenging. In addition, damage mechanisms for RCC due to dynamic impact of debris such as foam and ice and damage mechanisms due to a static loading were, as expected, not equivalent.

  12. Microcantilever bend testing and finite element simulations of HIP-ed interface-free bulk Al and Al-Al HIP bonded interfaces

    NASA Astrophysics Data System (ADS)

    Mara, Nathan A.; Crapps, Justin; Wynn, Thomas A.; Clarke, Kester D.; Antoniou, Antonia; Dickerson, Patricia O.; Dombrowski, David E.; Mihaila, Bogdan

    2013-07-01

    We report on the strength of Al-Al interfaces and the effects of chemical segregation and interfacial void formation on bond strength using microcantilever bend testing. Interfaces are synthesised via hot isostatic pressing. Microcantilevers of several nominal dimensions were fabricated via focused ion beam and deformed in a nanoindenter. We find increased cantilever strength as a function of decreasing sample size, with a linear dependence of the yield strength on the inverse square root of the length scale characteristic to the cantilever cross-section. The presence of pores and chemical segregation decreases the yield strength of the material by 17% and the accommodated strain energy by 10-15% for strain values in the 6-12% range.

  13. Creep Behavior of P92 Steel in the Steam Environment at 600 °C Using Miniature Three-Point Bend Test

    NASA Astrophysics Data System (ADS)

    Huang, Yuhui; Xuan, Fu-Zhen

    2016-12-01

    A miniature three-point bend test system with steam-circulating device was introduced in order to study the interaction behavior between steam oxidation and tensile, compressive creep of P92 steel at 600 °C. It was observed that the formation of oxidation scale accelerated creep deformation which induced by reducing the effective stress on underlying metal. The oxidation mechanisms as well as oxidation kinetics on tensile and compressive surface were examined by scanning electron microscope, x-ray diffraction and energy-dispersive spectrometer. It can be revealed that applied tensile and compressive loading had strong influence on oxidation rate rather than on oxidation mechanism. Furthermore, a mechanical model coupled with oxidation scale growth was proposed to predict the deformation rate of the miniature three-point specimen which could agree well with the experimental results.

  14. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  15. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  16. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  17. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  18. 46 CFR 56.80-5 - Bending.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Forming § 56.80-5 Bending. Pipe may be bent by any hot or cold method and to any radius which will result in a bend surface free of cracks, as determined by a method of inspection specified in the design... ultrasonics or other acceptable method. Alternatively, the pipe may be drilled, gaged, and fitted with a...

  19. Compression-bending of multi-component semi-rigid columns in response to axial loads and conjugate reciprocal extension-prediction of mechanical behaviours and implications for structural design.

    PubMed

    Lau, Ernest W

    2013-01-01

    The mathematical modelling of column buckling or beam bending under an axial or transverse load is well established. However, the existent models generally assume a high degree of symmetry in the structure of the column and minor longitudinal and transverse displacements. The situation when the column is made of several components with different mechanical properties asymmetrically distributed in the transverse section, semi-rigid, and subjected to multiple axial loads with significant longitudinal and transverse displacements through compression and bending has not been well characterised. A more comprehensive theoretical model allowing for these possibilities and assuming a circular arc contour for the bend is developed, and used to establish the bending axes, balance between compression and bending, and equivalent stiffness of the column. In certain situations, such as with pull cable catheters commonly used for minimally invasive surgical procedures, the compression loads are applied via cables running through channels inside a semi-rigid column. The model predicts the mathematical relationships between the radius of curvature of the bend and the tension in and normal force exerted by such cables. Conjugate extension with reciprocal compression-bending is a special structural arrangement for a semi-rigid column such that extension of one segment is linked to compression-bending of another by inextensible cables running between them. Leads are cords containing insulated electrical conductor coil and cables between the heart muscle and cardiac implantable electronic devices. Leads can behave like pull cable catheters through differential component pulling, providing a possible mechanism for inside-out abrasion and conductor cable externalisation. Certain design features may predispose to this mode of structural failure. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Experimental Characterization of Stretch-Bending Formability of AHSS Sheets

    NASA Astrophysics Data System (ADS)

    Kitting, Daniela; Ofenheimer, Aldo; Pauli, Heinrich; Till, Edwin T.

    2011-05-01

    Deformation conditions of combined stretching and bending are known to enhance material formability compared to forming conditions without bending (e.g. in-plane stretching). These phenomena can be observed for most conventional steel grades but is even more pronounced for Advanced High Strength Steel (AHSS) sheets. Consequently, there is an urgent need in industry to quantify the phenomena of enhanced material formability due to bending effects. In this work new stretch-bend test setups are presented which can be used in addition to the conventional Angular Stretch Bend Test to systematically investigate the influence of various stretch-bending deformation conditions on the formability of AHSS sheets.

  1. Tailoring the bending stiffness of elastomeric dual-matrix composites

    NASA Astrophysics Data System (ADS)

    Platt, David Lewis

    Aircraft structural design is becoming increasingly oriented towards multifunctional structures, which are capable of supporting large loads while exhibiting additional functional capabilities; morphing is an example. Composite materials provide the perfect testbed for such morphing technologies. Dual-matrix composites are being investigated by a number of researchers, primarily for use in deployable structures. This work investigates a more load-intensive application in aircraft cabin interiors. A morphing composite meal-tray table prototype is fabricated and tested. The macromechanics of dual-matrix laminates are investigated, with the focus being the tailoring of the bending stiffness of such laminates. The cross-section anticlastic deflections of +/-45 degree layups, due to high Poisson ratios, are shown to increase the bending stiffness of the laminate, resulting from an increased second moment of area. A predictive model for bending stiffness is constructed, compared with FEA and experiments, and its limitations in predicting woven-fabric composite behaviour are discussed.

  2. Analytical model for a polymer optical fiber under dynamic bending

    NASA Astrophysics Data System (ADS)

    Leal Junior, Arnaldo G.; Frizera, Anselmo; Pontes, Maria José

    2017-08-01

    Advantages such as sensibility in bending, high fracture toughness, and high sensibility in strain enable the application of polymer optical fibers as sensors for strain, temperature, level, and for angle measurements. In order to enhance the sensor design, this paper presents an analytical model for a side polished polymer optical fiber under dynamic bending. Differently from analytical models that use only the geometrical optics approach with no correction for the stress-optical effects, here the refractive index is corrected at every bending angle to consider the stress-optical effects observed polymer optical fibers. Furthermore, the viscoelastic response of the polymer is also considered. The model is validated in quasi-static and dynamic tests for a polymer optical fiber curvature sensor. Results show good agreement between the model and the experiments.

  3. Phase trombones with bending

    SciTech Connect

    Courant, E.D.; Garren, A.

    1985-10-01

    The phase shifting trombones considered up to now for SSC application consisted of sets of evenly spaced quadrupoles separated by drift spaces. One such trombone was placed between a dispersion suppressor and a crossing insertion, so that the trombone had zero dispersion. With such trombones, it is possible to change {beta}{sup *} at constant tune, or to change the tunes by several units without altering the cell phase advances in the arcs. An objection to the above type of phase trombone is that it adds to the circumference, since no bending is included. This objection may or may not be valid depending on the potential usefulness of the drift spaces in them. In this note the authors show an alternative trombone design in which dipoles are included between the quadrupoles as in the normal arc cells. Since these trombones have dispersion, they are placed at the ends of the arcs, to be followed in turn by the dispersion suppressors and crossing insertions.

  4. Designing a Gas Test Loop for the Advanced Test Reactor

    SciTech Connect

    James R. Parry

    2005-11-01

    The Generation IV Reactor Program and the Advanced Fuel Cycle Initiative are investigating some new reactor concepts which require extensive materials and fuels testing in a fast neutron spectrum. The capability to test materials and fuels in a fast neutron flux in the United States is very limited to non-existent. It has been proposed to install a gas test loop (GTL) in one of the lobes of the Advanced Test Reactor (ATR) at the Idaho National Laboratory and harden the spectrum to provide some fast neutron flux testing capabilities in the United States. This paper describes the neutronics investigation into the design of the GTL for the ATR.

  5. Los Alamos Novel Rocket Design Flight Tested

    ScienceCinema

    Tappan, Bryce

    2016-07-12

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  6. Los Alamos Novel Rocket Design Flight Tested

    SciTech Connect

    Tappan, Bryce

    2014-10-23

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  7. Results of Sediment Sampling and Elutriate Testing at the Proposed Little Sioux Bend Shallow Water Habitat Project Site

    DTIC Science & Technology

    2013-04-01

    5 2.2 Section 303( d ) Impaired Waters Listings...advisory has recently been removed based on recent fish tissue sampling (NDEQ, 2012). 2.2 Section 303( d ) Impaired Waters Listings Section 303( d ) of...the Federal CWA requires States to evaluate water quality conditions in designated waterbodies, and list as impaired (i.e. 303( d ) list) any

  8. Testing Multiple Outcomes in Repeated Measures Designs

    ERIC Educational Resources Information Center

    Lix, Lisa M.; Sajobi, Tolulope

    2010-01-01

    This study investigates procedures for controlling the familywise error rate (FWR) when testing hypotheses about multiple, correlated outcome variables in repeated measures (RM) designs. A content analysis of RM research articles published in 4 psychology journals revealed that 3 quarters of studies tested hypotheses about 2 or more outcome…

  9. Testing Multiple Outcomes in Repeated Measures Designs

    ERIC Educational Resources Information Center

    Lix, Lisa M.; Sajobi, Tolulope

    2010-01-01

    This study investigates procedures for controlling the familywise error rate (FWR) when testing hypotheses about multiple, correlated outcome variables in repeated measures (RM) designs. A content analysis of RM research articles published in 4 psychology journals revealed that 3 quarters of studies tested hypotheses about 2 or more outcome…

  10. Design and testing of cryogenic target systems

    SciTech Connect

    Alexander, N B; Baugh, W A; Bernat, T P; Besenbruch, G E; Boline, K K; Brown, L C; Collins, G P; Gibson, C R; Goodin, D T; Harding, D R; Nobile, A; Schultz, K R; Steimke, R E

    1999-09-09

    General Atomics (GA) together with the University of Rochester/Laboratory for Laser Energetics (UR/LLE) and Los Alamos National Laboratory (LANL), has designed the OMEGA Cryogenic Target System. This system fills, cools, and layers DT targets and places them in the center of the OMEGA Target Chamber. All equipment was procured, assembled, and tested at GA and UR/LLE. GA along with Lawrence Livermore National Laboratory and LANL is designing a test unit to evaluate the key process parameters and design issues associated with fielding cryogenic targets on the National Ignition Facility.

  11. An evaluation of the sandwich beam in four-point bending as a compressive test method for composites

    NASA Technical Reports Server (NTRS)

    Shuart, M. J.; Herakovich, C. T.

    1978-01-01

    The experimental phase of the study included compressive tests on HTS/PMR-15 graphite/polyimide, 2024-T3 aluminum alloy, and 5052 aluminum honeycomb at room temperature, and tensile tests on graphite/polyimide at room temperature, -157 C, and 316 C. Elastic properties and strength data are presented for three laminates. The room temperature elastic properties were generally found to differ in tension and compression with Young's modulus values differing by as much as twenty-six percent. The effect of temperature on modulus and strength was shown to be laminate dependent. A three-dimensional finite element analysis predicted an essentially uniform, uniaxial compressive stress state in the top flange test section of the sandwich beam. In conclusion, the sandwich beam can be used to obtain accurate, reliable Young's modulus and Poisson's ratio data for advanced composites; however, the ultimate compressive stress for some laminates may be influenced by the specimen geometry.

  12. Optical Metamaterial Design, Fabrication, and Test

    DTIC Science & Technology

    2011-03-01

    This work will focus on the development of metamaterials operating in the visible and infrared which will be constructed and tested for basic optical...permittivity at an infrared wavelength. The investigations into the 3D material did yield a possible for design using a novel material for the dielectric, but...16 2.4 Testing Using Spectrophotometry .......................................................................16 2.5 Testing Using Fourier

  13. Failure Behavior of Plasma-Sprayed Yttria-Stabilized Zirconia Thermal Barrier Coatings Under Three-Point Bending Test via Acoustic Emission Technique

    NASA Astrophysics Data System (ADS)

    Wang, L.; Ni, J. X.; Shao, F.; Yang, J. S.; Zhong, X. H.; Zhao, H. Y.; Liu, C. G.; Tao, S. Y.; Wang, Y.; Li, D. Y.

    2017-01-01

    In this paper, the failure behavior of plasma-sprayed yttria-stabilized zirconia thermal barrier coatings fabricated by atmospheric plasma spraying (APS-TBCs) under three-point bending (3PB) test has been characterized via acoustic emission (AE) technique. Linear positioning method has been adopted to monitor dynamic failure process of the APS-TBCs under 3PB test. The investigation results indicate that the variation of AE parameters (AE event counts, amplitudes and AE energy) corresponds well with the change of stress-strain curve of the loading processes. The failure mechanism was analyzed based on the characteristics of AE parameters. The distribution of frequency of crack propagation has been obtained. The AE signals came from two aspects: i.e., plastic deformation of substrates, initiation and propagation of the cracks in the coatings. The AE analysis combined with cross-sectional observation has indicated that many critical cracks initiate at the surface of the top-coat. And some main cracks tend to propagate toward the substrate/bond-coat interface. The actual failure mechanism of the APS-TBCs under 3PB test is attributed to the debonding of metallic coating from the substrates and the propagation of the horizontal crack along the substrate/bond-coat interface under the action of flexural moment.

  14. Evaluation of constraint methodologies applied to a shallow-flaw cruciform bend specimen tested under biaxial loading conditions

    SciTech Connect

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-01-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a prototypic, far-field. out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies. namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness, the conventional maximum principal stress criterion indicated no effect.

  15. Fracture assessment of HSST Plate 14 shallow-flaw cruciform bend specimens tested under biaxial loading conditions

    SciTech Connect

    Bass, B.R.; McAfee, W.J.; Williams, P.T.; Pennell, W.E.

    1998-06-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow surface flaws. Matrices of cruciform beam tests were developed to investigate and quantify the effects of temperature, biaxial loading, and specimen size on fracture initiation toughness of two-dimensional (constant depth), shallow, surface flaws. The cruciform beam specimens were developed at Oak Ridge National Laboratory (ORNL) to introduce a far-field, out-of-plane biaxial stress component in the test section that approximates the nonlinear stresses resulting from pressurized-thermal-shock or pressure-temperature loading of an RPV. Tests were conducted under biaxial load ratios ranging from uniaxial to equibiaxial. These tests demonstrated that biaxial loading can have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for an RPV material. The cruciform fracture toughness data were used to evaluate fracture methodologies for predicting the observed effects of biaxial loading on shallow-flaw fracture toughness. Initial emphasis was placed on assessment of stress-based methodologies, namely, the J-Q formulation, the Dodds-Anderson toughness scaling model, and the Weibull approach. Applications of these methodologies based on the hydrostatic stress fracture criterion indicated an effect of loading-biaxiality on fracture toughness; the conventional maximum principal stress criterion indicated no effect. A three-parameter Weibull model based on the hydrostatic stress criterion is shown to correlate the experimentally observed biaxial effect on cleavage fracture toughness by providing a scaling mechanism between uniaxial and biaxial loading states.

  16. Effect of train carbody's parameters on vertical bending stiffness performance

    NASA Astrophysics Data System (ADS)

    Yang, Guangwu; Wang, Changke; Xiang, Futeng; Xiao, Shoune

    2016-10-01

    Finite element analysis(FEA) and modal test are main methods to give the first-order vertical bending vibration frequency of train carbody at present, but they are inefficiency and waste plenty of time. Based on Timoshenko beam theory, the bending deformation, moment of inertia and shear deformation are considered. Carbody is divided into some parts with the same length, and it's stiffness is calculated with series principle, it's cross section area, moment of inertia and shear shape coefficient is equivalent by segment length, and the fimal corrected first-order vertical bending vibration frequency analytical formula is deduced. There are 6 simple carbodies and 1 real carbody as examples to test the formula, all analysis frequencies are very close to their FEA frequencies, and especially for the real carbody, the error between analysis and experiment frequency is 0.75%. Based on the analytic formula, sensitivity analysis of the real carbody's design parameters is done, and some main parameters are found. The series principle of carbody stiffness is introduced into Timoshenko beam theory to deduce a formula, which can estimate the first-order vertical bending vibration frequency of carbody quickly without traditional FEA method and provide a reference to design engineers.

  17. Generating circuit tests by exploiting designed behavior

    NASA Astrophysics Data System (ADS)

    Shirley, Mark H.

    1988-12-01

    Generating tests for sequential devices is one of the hardest problems in designing and manufacturing digital circuits. This task is difficult primarily because internal components are accessible only indirectly, forcing a test generator to use the surrounding components collectively as a probe for detecting faults. This in turn forces the test generator to reason about complex interactions between the behaviors of these surrounding components. Current automated solutions are becoming ineffective as designs grow larger and more complex. Yet, despite the complexity, human experts remain remarkably successful, in part, because they use knowledge from many sources and use a variety of reasoning techniques. This thesis exploits several kinds of expert knowledge about circuits and test generation not used by the current algorithms. First, many test generation problems can be solved efficiently using operation relations, a novel representation of circuit behavior that connects internal component operations with directly executable circuit operations. Operation relations can be computed efficiently for sequential circuits that provide few operations at their interfaces by searching traces of simulated circuit behavior. Second, experts write test programs rather than test vectors because programs are a more readable and compact representation for tests than vectors are. Test programs can be constructed automatically by merging test program fragments using expert supplied goal-refined rules and domain independent planning techniques from artificial intelligence.

  18. Design and Test of the CC Cryostat Head Cart

    SciTech Connect

    Jaques, Al; /Fermilab

    1989-08-08

    This Engineering Note documents the design of the stand to be used to transport the CC Cryostat heads into the D-Zero clean room. Due to the width of the clean room access door, the heads will have to be upright to fit through. This head cart will hold the heads upright and wheel them into the clean room on a guided track. Before the wheels are placed on the heat cart, it will be used as a stand to place the heads on for the purpose of test fitting the super insulation. The head cart will not only be structurally sufficient to support the weight of the heads but also stiff enough to allow a maximum deflection of 1/2-inch at the end of the 48-inch cylinder. The heaviest head assembly weighs about 9000 pounds. Following A.I.S.C. specifications and using a 9000 pound design load, the head cart was initially designed and built and later modified in order to meet the deflection requirements. Bending and tension stresses were limited to two thirds the yield strength. Weld and shear stresses are limited to 0.4*Fy. The C7 X 12.25 channels, the L2.5 X 2.5 X 0.25 angles adn the 1/2-inch plate are all A36 steel. In order to validate the need for an end plate in the 48-inch cylinder, an ANSYS model was created of the cylinder itself to determine it's rigidity under a point load applied at it's outer end. Appendix D contains the results which demonstrate the rigidity of the cylinder-end plate assembly. Also included is a Frame-Mac simulation of the head cart which was used to estimate the deflection at the cylinder end. A load test was performed to 133% of the rated capacity, or 12,000 pounds. The test load was incrementally applied using a crane and hook scale. A graph of deflection vs. load is shown in Appendix E. A spreader beam was designed and built to properly test the head cart. Stress calculations for this test spreader beam are included in Appendix C.

  19. Marker Sequential Test (MaST) design.

    PubMed

    Freidlin, Boris; Korn, Edward L; Gray, Robert

    2014-02-01

    New targeted anticancer therapies often benefit only a subset of patients with a given cancer. Definitive evaluation of these agents may require phase III randomized clinical trial designs that integrate evaluation of the new treatment and the predictive ability of the biomarker that putatively determines the sensitive subset. We propose a new integrated biomarker design, the Marker Sequential Test (MaST) design, that allows sequential testing of the treatment effect in the biomarker subgroups and overall population while controlling the relevant type I error rates. After defining the testing and error framework for integrated biomarker designs, we review the commonly used approaches to integrated biomarker testing. We then present a general form of the MaST design and describe how it can be used to provide proper control of false-positive error rates for biomarker-positive and biomarker-negative subgroups. The operating characteristics of the MaST design are compared by analytical methods and simulations to the sequential subgroup-specific design that sequentially assesses the treatment effect in the biomarker subgroups. Practical aspects of MaST design implementation are discussed. The MaST design is shown to have higher power relative to the sequential subgroup-specific design in situations where the treatment effect is homogeneous across biomarker subgroups, while preserving the power for settings where treatment benefit is limited to biomarker-positive subgroup. For example, in the time-to-event setting considered with 30% biomarker-positive prevalence, the MaST design provides up to a 30% increase in power in the biomarker-positive and biomarker-negative subgroups when the treatment benefits all patients equally, while sustaining less than a 2% loss of power against alternatives where the benefit is limited to the biomarker-positive subgroup. The proposed design is appropriate for settings where it is reasonable to assume that the treatment will not be

  20. Reaction wheel design, construction and qualification testing

    NASA Astrophysics Data System (ADS)

    Proper, Ian

    This thesis examines the design, construction, and space-qualification testing of a microsatellite class reaction wheel. A literature review compares both currently and formerly operational, as well as commercially available reaction wheel assemblies, to assess the torque and momentum generation capabilities relative to the masses of the respective units. Several potential software models for a prototype reaction wheel are constructed and compared to the units described in the literature review to determine feasibility of operation. Choosing a particular model, the prototype wheel is then constructed and baseline tests are performed to determine its operational characteristics. Finally, a series of qualification tests are performed: a life test, a vibration test and a thermal vacuum test. These tests aim to validate the ability of the prototype reaction wheel unit to operate for at least a six-month mission in a typical low Earth orbit environment.

  1. Discovering Gee's Bend Quilts

    ERIC Educational Resources Information Center

    Johnson, Ann

    2008-01-01

    Gee's Bend is a small community near Selma, Alabama where cotton plantations filled the land before the Civil War. After the war, the freed slaves of the plantations worked as tenant farmers and founded an African-American community. In 2002, the women of this community brought international attention and acclaim to Gee's Bend through the art of…

  2. Discovering Gee's Bend Quilts

    ERIC Educational Resources Information Center

    Johnson, Ann

    2008-01-01

    Gee's Bend is a small community near Selma, Alabama where cotton plantations filled the land before the Civil War. After the war, the freed slaves of the plantations worked as tenant farmers and founded an African-American community. In 2002, the women of this community brought international attention and acclaim to Gee's Bend through the art of…

  3. Microhole Tubing Bending Report

    DOE Data Explorer

    Oglesby, Ken

    2012-01-01

    A downhole tubing bending study was made and is reported herein. IT contains a report and 2 excel spreadsheets to calculate tubing bending and to estimate contact points of the tubing to the drilled hole wall (creating a new support point).

  4. Lithium Circuit Test Section Design and Fabrication

    SciTech Connect

    Godfroy, Thomas; Garber, Anne; Martin, James

    2006-01-20

    The Early Flight Fission -- Test Facilities (EFF-TF) team has designed and built an actively pumped lithium flow circuit. Modifications were made to a circuit originally designed for NaK to enable the use of lithium that included application specific instrumentation and hardware. Component scale freeze/thaw tests were conducted to both gain experience with handling and behavior of lithium in solid and liquid form and to supply anchor data for a Generalized Fluid System Simulation Program (GFSSP) model that was modified to include the physics for freeze/thaw transitions. Void formation was investigated. The basic circuit components include: reactor segment, lithium to gas heat exchanger, electromagnetic (EM) liquid metal pump, load/drain reservoir, expansion reservoir, instrumentation, and trace heaters. This paper discusses the overall system design and build and the component testing findings.

  5. Lithium Circuit Test Section Design and Fabrication

    NASA Astrophysics Data System (ADS)

    Godfroy, Thomas; Garber, Anne; Martin, James

    2006-01-01

    The Early Flight Fission - Test Facilities (EFF-TF) team has designed and built an actively pumped lithium flow circuit. Modifications were made to a circuit originally designed for NaK to enable the use of lithium that included application specific instrumentation and hardware. Component scale freeze/thaw tests were conducted to both gain experience with handling and behavior of lithium in solid and liquid form and to supply anchor data for a Generalized Fluid System Simulation Program (GFSSP) model that was modified to include the physics for freeze/thaw transitions. Void formation was investigated. The basic circuit components include: reactor segment, lithium to gas heat exchanger, electromagnetic (EM) liquid metal pump, load/drain reservoir, expansion reservoir, instrumentation, and trace heaters. This paper discusses the overall system design and build and the component testing findings.

  6. Certification Testing Approach for Propulsion System Design

    NASA Technical Reports Server (NTRS)

    Rodriguez, Henry; Popp, Chris

    2006-01-01

    The Certification of Propulsion Systems is costly and complex, involving development and qualification testing. The desire of the certification process is to assure all requirements can be demonstrated to be compliant. The purpose of this paper is to address the technical design concerns of certifying a propulsion system for flight. Presented are Pressurization, Tankage, Feed System and Combustion Instability concerns. Propulsion System Engineers are challenged with the dilemma for testing new systems to specific levels to reduce risk yet maintain budgetary targets. A methodical approach is presented to define the types of test suitable to address the technical issues for qualifying systems for retiring the risk levels. Experience of the lessons learned from supporting the Shuttle Program for Main Propulsion and On Orbit Propulsions Systems as well as previous collaborations on design concerns for certifying propulsion systems are utilized to address design concerns and verification approaches.

  7. Lithium Circuit Test Section Design and Fabrication

    NASA Technical Reports Server (NTRS)

    Godfroy, Thomas; Garber, Anne

    2006-01-01

    The Early Flight Fission - Test Facilities (EFF-TF) team has designed and built an actively pumped lithium flow circuit. Modifications were made to a circuit originally designed for NaK to enable the use of lithium that included application specific instrumentation and hardware. Component scale freeze/thaw tests were conducted to both gain experience with handling and behavior of lithium in solid and liquid form and to supply anchor data for a Generalized Fluid System Simulation Program (GFSSP) model that was modified to include the physics for freeze/thaw transitions. Void formation was investigated. The basic circuit components include: reactor segment, lithium to gas heat exchanger, electromagnetic (EM) liquid metal pump, load/drain reservoir, expansion reservoir, instrumentation, and trace heaters. This paper will discuss the overall system design and build and the component testing findings.

  8. Design, development and field testing of Cecil

    SciTech Connect

    Trovato, S.A. ); Ruggieri, S.K. )

    1990-01-01

    Inspection and cleaning of the secondary side of a pressurized water reactor (PWR) steam generator should be performed on a regular basis to prevent the degradation and early replacement of this equipment due to corrosion. Corrosion products, or sludge, settle in the secondary side of the steam generator and promote corrosion of the tube bundle. The CECIL robot was developed to improve inspection and cleaning of the secondary side of a steam generator. This paper describes the evolution in design of the CECIL robot. The design, development and field testing of the robot at India Point 2 nuclear station are discussed. Particular emphasis is placed on the fourth generation of its design, CECIL-4. The importance of iteration in design, test, fabrication and field application of mobile robots in a nuclear power station is discussed.

  9. Design and Testing of High Performance Brushes.

    DTIC Science & Technology

    1982-03-01

    with the development of compact homopolar motors and generators, in that no known electrical brushes were capable of meeting the design requirements...seems that unlubricated metal to metal contact brushes, lightly loaded and with a large number of a-spots, will be used not only in the homopolar ...serviceable and quite versatile, brush testing apparatus is alike, since The major goal in designing the apparatus they basically consist of a motor and axle

  10. Designing, engineering, and testing wood structures

    NASA Technical Reports Server (NTRS)

    Gorman, Thomas M.

    1992-01-01

    The objective of this paper is to introduce basic structural engineering concepts in a clear, simple manner while actively involving students. This project emphasizes the fact that a good design uses materials efficiently. The test structure in this experiment can easily be built and has various design options. Even when the structure is loaded to collapsing, only one or two pieces usually break, leaving the remaining pieces intact and reusable.

  11. Occipital bending in schizophrenia.

    PubMed

    Maller, Jerome J; Anderson, Rodney J; Thomson, Richard H; Daskalakis, Zafiris J; Rosenfeld, Jeffrey V; Fitzgerald, Paul B

    2017-01-01

    To investigate the prevalence of occipital bending (an occipital lobe crossing or twisting across the midline) in subjects with schizophrenia and matched healthy controls. Occipital bending prevalence was investigated in 37 patients with schizophrenia and 44 healthy controls. Ratings showed that prevalence was nearly three times higher among schizophrenia patients (13/37 [35.1%]) than in control subjects (6/44 [13.6%]). Furthermore, those with schizophrenia had greater normalized gray matter volume but less white matter volume and had larger brain-to-cranial ratio. The results suggest that occipital bending is more prevalent among schizophrenia patients than healthy subjects and that schizophrenia patients have different gray matter-white matter proportions. Although the cause and clinical ramifications of occipital bending are unclear, the results infer that occipital bending may be a marker of psychiatric illness.

  12. DESIGN AND SHIELDING OF A BEAM LINE FROM ELENA TO ATRAP USING ELECTROSTATIC QUADRUPOLE LENSES AND BENDS

    SciTech Connect

    Yuri, Yosuke; Lee, Edward P.

    2010-09-01

    The construction of the Extra Low ENergy Antiprotons (ELENA) upgrade to the Antiproton Decelerator (AD) ring has been proposed at CERN to produce a greatly increased current of low-energy antiprotons for various experiments including anti-hydrogen studies. This upgrade involves the addition of a small storage ring and electrostatic beam lines. The 5.3-MeV antiproton beams from AD are decelerated down to 100 keV in the compact ring and transported to each experimental apparatus. In this paper, we describe an electrostatic beam line from the ELENA ring to the ATRAP experimental apparatus and magnetic shielding of the low-energy beam line against the ATRAP superconducting solenoid magnet. A possible rough conceptual design of this system is displayed.

  13. Conditional statistical inference with multistage testing designs.

    PubMed

    Zwitser, Robert J; Maris, Gunter

    2015-03-01

    In this paper it is demonstrated how statistical inference from multistage test designs can be made based on the conditional likelihood. Special attention is given to parameter estimation, as well as the evaluation of model fit. Two reasons are provided why the fit of simple measurement models is expected to be better in adaptive designs, compared to linear designs: more parameters are available for the same number of observations; and undesirable response behavior, like slipping and guessing, might be avoided owing to a better match between item difficulty and examinee proficiency. The results are illustrated with simulated data, as well as with real data.

  14. Hardened engineering test building: Conceptual design report

    SciTech Connect

    Not Available

    1984-05-01

    Both the special nuclear materials nuclear explosive-like assemblies (SNM NELA) engineering tests and the intrinsic radiation (INRAD) activity is a programmatic necessity supported by Lawrence Livermore National Laboratory (LLNL) management. A new facility conforming to DOE standards for hardening and providing adequate security is an urgent requirement. The total project cost of $3,300,000 includes site improvements, building construction, and supporting utility services, as well as engineering services. The conceptual design in this report is based on functional requirements and the applicable design criteria. The design is the result of close interaction between LLNL personnel and the conceptual design team. Siting, building configuration, structural method, material selection, and mechanical and electrical systems were considered in the course of the design process. The concepts were evaluated from the viewpoints of cost effectiveness, energy conservation, functional requirements, operational patterns, and the creation of a desirable working environment.

  15. Advanced wing design survivability testing and results

    NASA Technical Reports Server (NTRS)

    Bruno, J.; Tobias, M.

    1992-01-01

    Composite wings on current operational aircraft are conservatively designed to account for stress/strain concentrations, and to assure specified damage tolerance. The technology that can lead to improved composite wing structures and associated structural efficiency is to increase design ultimate strain levels beyond their current limit of 3500 to 4000 micro-in/in to 6000 micro-in/in without sacrificing structural integrity, durability, damage tolerance, or survivability. Grumman, under the sponsorship of the Naval Air Development Center (NADC), has developed a high-strain composite wing design for a subsonic aircraft wing using novel and innovative design concepts and manufacturing methods, while maintaining a state-of-the-art fiber/resin system. The current advanced wing design effort addressed a tactical subsonic aircraft wing using previously developed, high-strain wing design concepts in conjunction with newer/emerging fiber and polymer matrix composite (PMC) materials to achieve the same goals, while reducing complexity. Two categories of advanced PMC materials were evaluated: toughened thermosets; and engineered thermoplastics. Advanced PMC materials offer the technological opportunity to take maximum advantage of improved material properties, physical characteristics, and tailorability to increase performance and survivability over current composite structure. Damage tolerance and survivability to various threats, in addition to structural integrity and durability, were key technical issues addressed during this study, and evaluated through test. This paper focuses on the live-fire testing, and the results performed to experimentally evaluate the survivability of the advanced wing design.

  16. A pressure transient test design expert system

    SciTech Connect

    MacAllister, D.J.; Kamal, M.M. )

    1991-09-01

    This paper describes an expert system for routine field use to optimize pressure transient test design and tool selection. The expert system first interacts with the user to determine the well type (exploration, injection, production, or observation) and then queries the user for such facts as reservoir layering, artificial lift, and fracturing. It sometimes asks clarifying questions for a variety of special cases. At this point, the expert system determines if the test is feasible. If not, the user has the option to quit or to continue test is feasible, the expert system calculates test design parameters using accepted technique from the literature and in-house experts. The expert system queries the user for additional data needed for test design calculations. The expert system produces an optimized test procedure and a list of appropriate tools from a data base supplied with the expert system. The tool data base is accessed by the expert system but maintained separately from the expert system code. This allows updates to the data base without the need for rewriting the expert system code. The user also can save and retrieve input data using another data base, making sensitivity studies easy to perform.

  17. FFAG lattice without opposite bends

    NASA Astrophysics Data System (ADS)

    Trbojevic, Dejan; Courant, Ernest D.; Garren, Al

    2000-08-01

    A future "neutrino factory" or Muon Collider requires fast muon acceleration before the storage ring. Several alternatives for fast muon acceleration have previously been considered. One of them is the FFAG (Fixed Field Alternating Gradient) synchrotron. The FFAG concept was developed in 1952 by K. R. Symon (ref. 1). The advantages of this design are the fixed magnetic field, large range of particle energy, simple RF; power supplies are simple, and there is no transition energy. But a drawback is that reverse bending magnets are included in the configuration; this increases the size and cost of the ring. Recently some modified FFAG lattice designs have been described where the amount of opposite bending was significantly reduced (ref. 2, ref. 3).

  18. Tunable waveguide bends with graphene-based anisotropic metamaterials

    NASA Astrophysics Data System (ADS)

    Chen, Zhao-xian; Chen, Ze-guo; Ming, Yang; Wu, Ying; Lu, Yan-qing

    2016-02-01

    We design tunable waveguide bends filled with graphene-based anisotropic metamaterials to achieve a nearly perfect bending effect. The anisotropic properties of the metamaterials can be described by the effective medium theory. The nearly perfect bending effect is demonstrated by finite element simulations of various structures with different bending curvatures and shapes. This effect is attributed to zero effective permittivity along the direction of propagation and matched effective impedance at the interfaces between the bending part and the dielectric waveguides. We envisage that the design will be applicable in the far-infrared and terahertz frequency ranges owing to the tunable dielectric responses of graphene.

  19. BETA (Bitter Electromagnet Testing Apparatus) Design and Testing

    NASA Astrophysics Data System (ADS)

    Bates, Evan; Birmingham, William; Rivera, William; Romero-Talamas, Carlos

    2016-10-01

    BETA is a 1T water cooled Bitter-type magnetic system that has been designed and constructed at the Dusty Plasma Laboratory of the University of Maryland, Baltimore County to serve as a prototype of a scaled 10T version. Currently the system is undergoing magnetic, thermal and mechanical testing to ensure safe operating conditions and to prove analytical design optimizations. These magnets will function as experimental tools for future dusty plasma based and collaborative experiments. An overview of design methods used for building a custom made Bitter magnet with user defined experimental constraints is reviewed. The three main design methods consist of minimizing the following: ohmic power, peak conductor temperatures, and stresses induced by Lorentz forces. We will also discuss the design of BETA which includes: the magnet core, pressure vessel, cooling system, power storage bank, high powered switching system, diagnostics with safety cutoff feedback, and data acquisition (DAQ)/magnet control Matlab code. Furthermore, we present experimental data from diagnostics for validation of our analytical preliminary design methodologies and finite element analysis calculations. BETA will contribute to the knowledge necessary to finalize the 10 T magnet design.

  20. SAPHIRE Change Design and Testing Procedure

    SciTech Connect

    Curtis Smith

    2010-02-01

    This document describes the procedure software developers of SAPHIRE follow when adding a new feature or revising an existing capability. This procedure first describes the general approach to changes, and then describes more specific processes. The process stages include design and development, testing, and documentation.

  1. Test Design with Cognition in Mind

    ERIC Educational Resources Information Center

    Gorin, Joanna S.

    2006-01-01

    One of the primary themes of the National Research Council's 2001 book "Knowing What Students Know" was the importance of cognition as a component of assessment design and measurement theory (NRC, 2001). One reaction to the book has been an increased use of sophisticated statistical methods to model cognitive information available in test data.…

  2. Siemens SOFC Test Article and Module Design

    SciTech Connect

    Pierre, Joseph F.

    2011-03-31

    Preliminary design studies of the 95 kWe-class SOFC test article continue resulting in a stack architecture of that is 1/3 of 250 kWe-class SOFC advanced module. The 95 kWeclass test article is envisioned to house 20 bundles (eight cells per bundle) of Delta8 cells with an active length of 100 cm. Significant progress was made in the conceptual design of the internal recirculation loop. Flow analyses were initiated in order to optimize the bundle row length for the 250 kWeclass advanced module. A preferred stack configuration based on acceptable flow and thermal distributions was identified. Potential module design and analysis issues associated with pressurized operation were identified.

  3. Backed Bending Actuator

    NASA Technical Reports Server (NTRS)

    Costen, Robert C.; Su, Ji

    2004-01-01

    Bending actuators of a proposed type would partly resemble ordinary bending actuators, but would include simple additional components that would render them capable of exerting large forces at small displacements. Like an ordinary bending actuator, an actuator according to the proposal would include a thin rectangular strip that would comprise two bonded layers (possibly made of electroactive polymers with surface electrodes) and would be clamped at one end in the manner of a cantilever beam. Unlike an ordinary bending actuator, the proposed device would include a rigid flat backplate that would support part of the bending strip against backward displacement; because of this feature, the proposed device is called a backed bending actuator. When an ordinary bending actuator is inactive, the strip typically lies flat, the tip displacement is zero, and the force exerted by the tip is zero. During activation, the tip exerts a transverse force and undergoes a bending displacement that results from the expansion or contraction of one or more of the bonded layers. The tip force of an ordinary bending actuator is inversely proportional to its length; hence, a long actuator tends to be weak. The figure depicts an ordinary bending actuator and the corresponding backed bending actuator. The bending, the tip displacement (d(sub t)), and the tip force (F) exerted by the ordinary bending actuator are well approximated by the conventional equations for the loading and deflection of a cantilever beam subject to a bending moment which, in this case, is applied by the differential expansion or contraction of the bonded layers. The bending, displacement, and tip force of the backed bending actuator are calculated similarly, except that it is necessary to account for the fact that the force F(sub b) that resists the displacement of the tip could be sufficient to push part of the strip against the backplate; in such a condition, the cantilever beam would be effectively shortened

  4. Design of a fusion engineering test facility

    SciTech Connect

    Sager, P.H.

    1980-01-01

    The fusion Engineering Test Facility (ETF) is being designed to provide for engineering testing capability in a program leading to the demonstration of fusion as a viable energy option. It will combine power-reactor-type components and subsystems into an integrated tokamak system and provide a test bed to test blanket modules in a fusion environment. Because of the uncertainties in impurity control two basic designs are being developed: a design with a bundle divertor (Design 1) and one with a poloidal divertor (Design 2). The two designs are similar where possible, the latter having somewhat larger toroidal field (TF) coils to accommodate removal of the larger torus sectors required for the single-null poloidal divertor. Both designs have a major radius of 5.4 m, a minor radius of 1.3 m, and a D-shaped plasma with an elongation of 1.6. Ten TF coils are incorporated in both designs, producing a toroidal field of 5.5 T on-axis. The ohmic heating and equilibrium field (EF) coils supply sufficient volt-seconds to produce a flat-top burn of 100 s and a duty cycle of 135 s, including a start of 12 s, a burn termination of 10 s, and a pumpdown of 13 s. The total fusion power during burn is 750 MW, giving a neutron wall loading of 1.5 MW/m/sup 2/. In Design 1 of the poloidal field (PF) coils except the fast-response EF coils are located outside the FT coils and are superconducting. The fast-response coils are located inside the TF coil bore near the torus and are normal conducting so that they can be easily replaced.In Design 2 all of the PF coils are located outside the TF coils and are superconducting. Ignition is achieved with 60 MW of neutral beam injection at 150 keV. Five megawatts of radio frequency heating (electron cyclotron resonance heating) is used to assist in the startup and limit the breakdown requirement to 25 V.

  5. Engineering design of vertical test stand cryostat

    SciTech Connect

    Suhane, S.K.; Sharma, N.K.; Raghavendra, S.; Joshi, S.C.; Das, S.; Kush, P.K.; Sahni, V.C.; Gupta, P.D.; Sylvester, C.; Rabehl, R.; Ozelis, J.; /Fermilab

    2011-03-01

    Under Indian Institutions and Fermilab collaboration, Raja Ramanna Centre for Advanced Technology and Fermi National Accelerator Laboratory are jointly developing 2K Vertical Test Stand (VTS) cryostats for testing SCRF cavities at 2K. The VTS cryostat has been designed for a large testing aperture of 86.36 cm for testing of 325 MHz Spoke resonators, 650 MHz and 1.3 GHz multi-cell SCRF cavities for Fermilab's Project-X. Units will be installed at Fermilab and RRCAT and used to test cavities for Project-X. A VTS cryostat comprises of liquid helium (LHe) vessel with internal magnetic shield, top insert plate equipped with cavity support stand and radiation shield, liquid nitrogen (LN{sub 2}) shield and vacuum vessel with external magnetic shield. The engineering design and analysis of VTS cryostat has been carried out using ASME B&PV Code and Finite Element Analysis. Design of internal and external magnetic shields was performed to limit the magnetic field inside LHe vessel at the cavity surface <1 {micro}T. Thermal analysis for LN{sub 2} shield has been performed to check the effectiveness of LN{sub 2} cooling and for compliance with ASME piping code allowable stresses.

  6. Analgesic effects of lidocaine, morphine and diclofenac on movement-induced nociception, as assessed by the Knee-Bend and CatWalk tests in a rat model of osteoarthritis.

    PubMed

    Ferreira-Gomes, Joana; Adães, Sara; Mendonça, Marcelo; Castro-Lopes, José Manuel

    2012-06-01

    Pain is the major symptom of osteoarthritis (OA) and the main reason for patients seeking medical care, but its treatment is not optimal. Animal studies are necessary to elucidate mechanisms underlying OA-induced pain and assess analgesics' efficacy. Previously, we showed that the Knee-Bend test and dynamic weight bearing by the CatWalk test are clinically relevant methods for assessing movement-induced nociception in the mono-iodoacetate (MIA) OA model. Using the same tests, in the present study we investigate the effects of lidocaine (5 mg, 10% solution, intra-articular), morphine (6 mg/kg, subcutaneous) and diclofenac (30 mg/kg per os) on nociceptive behavior in OA animals, on days 3 and 20 of OA evolution. Morphine reduced nociceptive behavior in both tests at both time-points. Lidocaine also decreased nociceptive behavior in both tests on day 3, but on day 20 only reduced the Knee-Bend score. Diclofenac was highly effective in both tests on day 3, while on day 20 it induced a less pronounced decrease in the Knee-Bend score and was ineffective in the CatWalk test. The results showed that the Knee-Bend and CatWalk tests are reliable alternative methods for evaluating movement-induced nociception in OA animals, and measure nociception in a clinically relevant way, since an analgesic profile similar to the one described in humans was observed. Therefore, these tests might be important as good predictors of drug efficacy. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Bending stresses due to torsion in cantilever box beams

    NASA Technical Reports Server (NTRS)

    Kuhn, Paul

    1935-01-01

    The paper beings with a brief discussion on the origin of the bending stresses in cantilever box beams under torsion. A critical survey of existing theory is followed by a summary of design formulas; this summary is based on the most complete solution published but omits all refinements considered unnecessary at the present state of development. Strain-gage tests made by NACA to obtained some experimental verification of the formulas are described next. Finally, the formulas are applied to a series of box beams previously static-tested by the U.S. Army Air Corps; the results show that the bending stresses due to torsion are responsible to a large extent for the free-edge type of failure frequently experienced in these tests.

  8. A Computerized Test of Design Fluency.

    PubMed

    Woods, David L; Wyma, John M; Herron, Timothy J; Yund, E William

    2016-01-01

    Tests of design fluency (DF) assess a participant's ability to generate geometric patterns and are thought to measure executive functions involving the non-dominant frontal lobe. Here, we describe the properties of a rapidly administered computerized design-fluency (C-DF) test that measures response times, and is automatically scored. In Experiment 1, we found that the number of unique patterns produced over 90 s by 180 control participants (ages 18 to 82 years) correlated with age, education, and daily computer-use. Each line in the continuous 4-line patterns required approximately 1.0 s to draw. The rate of pattern production and the incidence of repeated patterns both increased over the 90 s test. Unique pattern z-scores (corrected for age and computer-use) correlated with the results of other neuropsychological tests performed on the same day. Experiment 2 analyzed C-DF test-retest reliability in 55 participants in three test sessions at weekly intervals and found high z-score intraclass correlation coefficients (ICC = 0.79). Z-scores in the first session did not differ significantly from those of Experiment 1, but performance improved significantly over repeated tests. Experiment 3 investigated the performance of Experiment 2 participants when instructed to simulate malingering. Z-scores were significantly reduced and pattern repetitions increased, but there was considerable overlap with the performance of the control population. Experiment 4 examined performance in veteran patients tested more than one year after traumatic brain injury (TBI). Patients with mild TBI performed within the normal range, but patients with severe TBI showed reduced z-scores. The C-DF test reliably measures visuospatial pattern generation ability and reveals performance deficits in patients with severe TBI.

  9. A Computerized Test of Design Fluency

    PubMed Central

    Woods, David L.; Wyma, John M.; Herron, Timothy J.; Yund, E. William

    2016-01-01

    Tests of design fluency (DF) assess a participant’s ability to generate geometric patterns and are thought to measure executive functions involving the non-dominant frontal lobe. Here, we describe the properties of a rapidly administered computerized design-fluency (C-DF) test that measures response times, and is automatically scored. In Experiment 1, we found that the number of unique patterns produced over 90 s by 180 control participants (ages 18 to 82 years) correlated with age, education, and daily computer-use. Each line in the continuous 4-line patterns required approximately 1.0 s to draw. The rate of pattern production and the incidence of repeated patterns both increased over the 90 s test. Unique pattern z-scores (corrected for age and computer-use) correlated with the results of other neuropsychological tests performed on the same day. Experiment 2 analyzed C-DF test-retest reliability in 55 participants in three test sessions at weekly intervals and found high z-score intraclass correlation coefficients (ICC = 0.79). Z-scores in the first session did not differ significantly from those of Experiment 1, but performance improved significantly over repeated tests. Experiment 3 investigated the performance of Experiment 2 participants when instructed to simulate malingering. Z-scores were significantly reduced and pattern repetitions increased, but there was considerable overlap with the performance of the control population. Experiment 4 examined performance in veteran patients tested more than one year after traumatic brain injury (TBI). Patients with mild TBI performed within the normal range, but patients with severe TBI showed reduced z-scores. The C-DF test reliably measures visuospatial pattern generation ability and reveals performance deficits in patients with severe TBI. PMID:27138985

  10. Design and Test of an Electrometer Test Track

    NASA Astrophysics Data System (ADS)

    Lui, C.

    2010-12-01

    I worked on a experiment that would help on testing the parts of the MSRG satellite of Stanford. The goal of my experiment is to figure out how far a probe can be moved from a piece of mass to still be able to measure the potential (voltage) between the two.A model designed in Solidworks will be used; this model is put in a vacuum chamber for precise results.

  11. Severe Accident Test Station Design Document

    SciTech Connect

    Snead, Mary A.; Yan, Yong; Howell, Michael; Keiser, James R.; Terrani, Kurt A.

    2015-09-01

    The purpose of the ORNL severe accident test station (SATS) is to provide a platform for evaluation of advanced fuels under projected beyond design basis accident (BDBA) conditions. The SATS delivers the capability to map the behavior of advanced fuels concepts under accident scenarios across various temperature and pressure profiles, steam and steam-hydrogen gas mixtures, and thermal shock. The overall facility will include parallel capabilities for examination of fuels and irradiated materials (in-cell) and non-irradiated materials (out-of-cell) at BDBA conditions as well as design basis accident (DBA) or loss of coolant accident (LOCA) conditions. Also, a supporting analytical infrastructure to provide the data-needs for the fuel-modeling components of the Fuel Cycle Research and Development (FCRD) program will be put in place in a parallel manner. This design report contains the information for the first, second and third phases of design and construction of the SATS. The first phase consisted of the design and construction of an out-of-cell BDBA module intended for examination of non-irradiated materials. The second phase of this work was to construct the BDBA in-cell module to test irradiated fuels and materials as well as the module for DBA (i.e. LOCA) testing out-of-cell, The third phase was to build the in-cell DBA module. The details of the design constraints and requirements for the in-cell facility have been closely captured during the deployment of the out-of-cell SATS modules to ensure effective future implementation of the in-cell modules.

  12. Design Analysis for a Scaled Erosion Test

    SciTech Connect

    Lee, S.Y.

    2002-04-10

    In support of a slurry wear evaluation in the pretreatment filtration and evaporation systems of RPP-WTP, Engineering Modeling and Simulation Group (EMSG) has developed the computational models to help guide component design and scaling decisions and to assist in the full-scale analyses. This report deals with the filtration system. In this project, computational fluid dynamics (CFD) methods were applied to ensure that the test facility design would capture the erosion phenomena expected in the full-scale cross-flow ultrafiltration facility. The literature survey was initially performed to identify the principal mechanisms of erosion for a solids laden fluid.

  13. Drag Reduction Tests on Supersonic Transport Design

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Langley researchers recently completed supersonic tests in the Unitary Plan Wind Tunnel on a nonlinear design for a supersonic transport. Although the drag reduction measured during the tests was not as great as that predicted using computational methods, significant drag reductions were achieved. Future tests will be conducted at a higher Reynolds number, which will be more representative of flight conditions. These tests will be used to identify a supersonic transport configuration that provides maximum drag reduction. Reducing drag decreases operating cost by improving fuel consumption and lowering aircraft weight. As a result, this research has the potential to help make a future high-speed civil transport (HSCT) an affordable means of travel for the flying public.

  14. Design, Fabrication and Test of Composite Curved Frames for Helicopter Fuselage Structure

    NASA Technical Reports Server (NTRS)

    Lowry, D. W.; Krebs, N. E.; Dobyns, A. L.

    1984-01-01

    Aspects of curved beam effects and their importance in designing composite frame structures are discussed. The curved beam effect induces radial flange loadings which in turn causes flange curling. This curling increases the axial flange stresses and induces transverse bending. These effects are more important in composite structures due to their general inability to redistribute stresses by general yielding, such as in metal structures. A detailed finite element analysis was conducted and used in the design of composite curved frame specimens. Five specimens were statically tested and compared with predicted and test strains. The curved frame effects must be accurately accounted for to avoid premature fracture; finite element methods can accurately predict most of the stresses and no elastic relief from curved beam effects occurred in the composite frames tested. Finite element studies are presented for comparative curved beam effects on composite and metal frames.

  15. Design, analysis, and testing of a metal matrix composite web/flange intersection

    NASA Technical Reports Server (NTRS)

    Biggers, S. B.; Knight, N. F., Jr.; Moran, S. G.; Olliffe, R.

    1992-01-01

    An experimental and analytical program to study the local design details of a typical T-shaped web/flange intersection made from a metal matrix composite is described. Loads creating flange bending were applied to specimens having different designs and boundary conditions. Finite element analyses were conducted on models of the test specimens to predict the structural response. The analyses correctly predict failure load, mode, and location in the fillet material in the intersection region of the web and the flange when specimen quality is good. The test program shows the importance of fabrication quality in the intersection region. The full-scale test program that led to the investigation of this local detail is also described.

  16. Deep Borehole Field Test Conceptual Design Report

    SciTech Connect

    Hardin, Ernest L.

    2016-09-30

    This report documents conceptual design development for the Deep Borehole Field Test (DBFT), including test packages (simulated waste packages, not containing waste) and a system for demonstrating emplacement and retrieval of those packages in the planned Field Test Borehole (FTB). For the DBFT to have demonstration value, it must be based on conceptualization of a deep borehole disposal (DBD) system. This document therefore identifies key options for a DBD system, describes an updated reference DBD concept, and derives a recommended concept for the DBFT demonstration. The objective of the DBFT is to confirm the safety and feasibility of the DBD concept for long-term isolation of radioactive waste. The conceptual design described in this report will demonstrate equipment and operations for safe waste handling and downhole emplacement of test packages, while contributing to an evaluation of the overall safety and practicality of the DBD concept. The DBFT also includes drilling and downhole characterization investigations that are described elsewhere (see Section 1). Importantly, no radioactive waste will be used in the DBFT, nor will the DBFT site be used for disposal of any type of waste. The foremost performance objective for conduct of the DBFT is to demonstrate safe operations in all aspects of the test.

  17. Design, manufacturing and characterization of aero-elastically scaled wind turbine blades for testing active and passive load alleviation techniques within a ABL wind tunnel

    NASA Astrophysics Data System (ADS)

    Campagnolo, Filippo; Bottasso, Carlo L.; Bettini, Paolo

    2014-06-01

    In the research described in this paper, a scaled wind turbine model featuring individual pitch control (IPC) capabilities, and equipped with aero-elastically scaled blades featuring passive load reduction capabilities (bend-twist coupling, BTC), was constructed to investigate, by means of wind tunnel testing, the load alleviation potential of BTC and its synergy with active load reduction techniques. The paper mainly focus on the design of the aero-elastic blades and their dynamic and static structural characterization. The experimental results highlight that manufactured blades show desired bend-twist coupling behavior and are a first milestone toward their testing in the wind tunnel.

  18. Spacecraft load, design and test philosophies

    NASA Technical Reports Server (NTRS)

    Wada, B. K.

    1986-01-01

    The development of spacecraft loads, design and test philosophies at the Jet Propulsion Laboratory (JPL) during the past 25 years is presented. Examples from the JPL's Viking, Voyager and Galileo spacecraft are used to explain the changes in philosophy necessary to meet the program requirements with a reduction in cost and schedule. Approaches to validate mathematical models of large structures which can't be ground tested as an overall system because of size and/or adverse effects of terrestrial conditions such as gravity are presented.

  19. Spacecraft load, design and test philosophies

    NASA Technical Reports Server (NTRS)

    Wada, B. K.

    1986-01-01

    The development of spacecraft loads, design and test philosophies at the Jet Propulsion Laboratory (JPL) during the past 25 years is presented. Examples from the JPL's Viking, Voyager and Galileo spacecraft are used to explain the changes in philosophy necessary to meet the program requirements with a reduction in cost and schedule. Approaches to validate mathematical models of large structures which can't be ground tested as an overall system because of size and/or adverse effects of terrestrial conditions such as gravity are presented.

  20. Design and testing of a double X-frame piezoelectric actuator

    NASA Astrophysics Data System (ADS)

    Hall, Steven R.; Tzianetopoulou, Theodora; Straub, Friedrich K.; Ngo, Hieu T.

    2000-06-01

    The development and testing of a new actuator for helicopter rotor control, the Double X-Frame, is described. The actuator is being developed for wind tunnel and flight testing on an MD-900 helicopter. The double X-frame actuator has a number of design innovations to improve its performance over the original X-frame design of Prechtl and Hall. First, the double X-frame design uses two X-frames operating in opposition, which allows the actuator stack preloads to be applied internally to the actuator, rather than through the actuation path. Second, the frames of the actuator have been modified to improve the actuator form factor, and increase the volume of active material in the actuator. Testing of the double X-frame piezoelectric actuator was conducted in order to determine its performance (stroke and stiffness) and robustness. In general, stiffness test data compared well with the analytical predictions. The actuator stroke was about 15% less than expected, probably due to the stack output being less in the actuator than as measured in single stack segment testing in the lab. The actuator was also tested dynamically, to determine its frequency response. Actuator robustness was evaluated by measuring its performance when subjected to the effects of blade bending, vibration, and centrifugal loading. Blade elastic bending and torsion deformations were simulated by shimming of the actuator mounts. To assess the impact of the blade vibrations, the actuator and bench test rig were mounted on a hydraulic shaker and subjected to flapwise or chordwise accelerations up to 30 g. To assess the impact of centrifugal force loading, the actuator and bench test rig were spun in the University of Maryland vacuum chamber, so that the actuator was subjected to realistic accelerations, up to 115% of nominal. Results showed that actuator output (force times stroke) was largely unaffected by dynamic and steady accelerations or elastic blade deformations.

  1. Composite transport wing technology development: Design development tests and advanced structural concepts

    NASA Technical Reports Server (NTRS)

    Griffin, Charles F.; Harvill, William E.

    1988-01-01

    Numerous design concepts, materials, and manufacturing methods were investigated for the covers and spars of a transport box wing. Cover panels and spar segments were fabricated and tested to verify the structural integrity of design concepts and fabrication techniques. Compression tests on stiffened panels demonstrated the ability of graphite/epoxy wing upper cover designs to achieve a 35 percent weight savings compared to the aluminum baseline. The impact damage tolerance of the designs and materials used for these panels limits the allowable compression strain and therefore the maximum achievable weight savings. Bending and shear tests on various spar designs verified an average weight savings of 37 percent compared to the aluminum baseline. Impact damage to spar webs did not significantly degrade structural performance. Predictions of spar web shear instability correlated well with measured performance. The structural integrity of spars manufactured by filament winding equalled or exceeded those fabricated by hand lay-up. The information obtained will be applied to the design, fabrication, and test of a full-scale section of a wing box. When completed, the tests on the technology integration box beam will demonstrate the structural integrity of an advanced composite wing design which is 25 percent lighter than the metal baseline.

  2. Crashworthy airframe design concepts: Fabrication and testing

    NASA Technical Reports Server (NTRS)

    Cronkhite, J. D.; Berry, V. L.

    1982-01-01

    Crashworthy floor concepts applicable to general aviation aircraft metal airframe structures were investigated. Initially several energy absorbing lower fuselage structure concepts were evaluated. Full scale floor sections representative of a twin engine, general aviation airplane lower fuselage structure were designed and fabricated. The floors featured an upper high strength platform with an energy absorbing, crushable structure underneath. Eighteen floors were fabricated that incorporated five different crushable subfloor concepts. The floors were then evaluated through static and dynamic testing. Computer programs NASTRAN and KRASH were used for the static and dynamic analysis of the floor section designs. Two twin engine airplane fuselages were modified to incorporate the most promising crashworthy floor sections for test evaluation.

  3. SP-100 design, safety, and testing

    NASA Technical Reports Server (NTRS)

    Cox, Carl. M.; Mahaffey, Michael M.; Smith, Gary L.

    1991-01-01

    The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major nuclear assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4-MWt nuclear and heat transport assembly.

  4. SP-100 design, safety, and testing

    NASA Technical Reports Server (NTRS)

    Cox, Carl. M.; Mahaffey, Michael M.; Smith, Gary L.

    1991-01-01

    The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major nuclear assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4-MWt nuclear and heat transport assembly.

  5. SP-100 design, safety, and testing

    NASA Astrophysics Data System (ADS)

    Cox, Carl. M.; Mahaffey, Michael M.; Smith, Gary L.

    The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major nuclear assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4-MWt nuclear and heat transport assembly.

  6. SP-100 design, safety, and testing

    NASA Astrophysics Data System (ADS)

    Smith, Gary L.; Cox, Carl M.; Mahaffey, Michael M.

    1990-05-01

    The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4 Mwt nuclear and heat transport assembly.

  7. SP-100 design, safety, and testing

    NASA Astrophysics Data System (ADS)

    Smith, Gary L.; Cox, Carl M.; Mahaffey, Michael M.

    1990-07-01

    The SP-100 Program is developing a nuclear reactor power system that can enhance and/or enable future civilian and military space missions. The program is directed to develop space reactor technology to provide electrical power in the range of tens to hundreds of kilowatts. The major nuclear assembly test is to be conducted at the Hanford Site near Richland, Washington, and is designed to validate the performance of the 2.4-MWt nuclear and heat transport assembly.

  8. Ceramic high temperature receiver design and tests

    NASA Technical Reports Server (NTRS)

    Davis, S. B.

    1982-01-01

    The High Temperature Solar Thermal Receiver, which was tested a Edwards AFB, CA during the winter of 1980-1981, evolved from technologies developed over a five year period of work. This receiver was tested at the Army Solar Furnace at White Sands, NM in 1976. The receiver, was tested successfully at 1768 deg F and showed thermal efficiencies of 85%. The results were sufficiently promising to lead ERDA to fund our development and test of a 250 kW receiver to measure the efficiency of an open cavity receiver atop a central tower of a heliostat field. This receiver was required to be design scalable to 10, 50, and 100 MW-electric sizes to show applicability to central power tower receivers. That receiver employed rectagular silicon carbide panels and vertical stanchions to achieve scalability. The construction was shown to be fully scalable; and the receiver was operated at temperatures up to 2000 deg F to achieve the performance goals of the experiment during tests at the GIT advanced components test facility during the fall of 1978.

  9. Wrapped multilayer insulation design and testing

    NASA Astrophysics Data System (ADS)

    Dye, S. A.; Tyler, P. N.; Mills, G. L.; Kopelove, A. B.

    2014-11-01

    New vehicles need improved cryogenic propellant storage and transfer capabilities for long duration missions. Multilayer insulation (MLI) for cryogenic propellant feedlines is much less effective than MLI tank insulation, with heat leak into spiral wrapped MLI on pipes 3-10 times higher than conventional tank MLI. Better insulation for cryogenic feed lines is an important enabling technology that could help NASA reach cryogenic propellant storage and transfer requirements. Improved insulation for Ground Support Equipment could reduce cryogen losses during launch vehicle loading. Wrapped-MLI (WMLI) is a high performance multilayer insulation using innovative discrete spacer technology specifically designed for cryogenic transfer lines and Vacuum Jacketed Pipe (VJP) to reduce heat flux. The poor performance of traditional MLI wrapped on feed lines is due in part to compression of the MLI layers, with increased interlayer contact and heat conduction. WMLI uses discrete spacers that maintain precise layer spacing, with a unique design to reduce heat leak. A Triple Orthogonal Disk spacer was engineered to minimize contact area/length ratio and reduce solid heat conduction for use in concentric MLI configurations. A new insulation, WMLI, was developed and tested. Novel polymer spacers were designed, analyzed and fabricated; different installation techniques were examined; and rapid prototype nested shell components to speed installation on real world piping were designed and tested. Prototypes were installed on tubing set test fixtures and heat flux measured via calorimetry. WMLI offered superior performance to traditional MLI installed on cryogenic pipe, with 2.2 W/m2 heat flux compared to 26.6 W/m2 for traditional spiral wrapped MLI (5 layers, 77-295 K). WMLI as inner insulation in VJP can offer heat leaks as low as 0.09 W/m, compared to industry standard products with 0.31 W/m. WMLI could enable improved spacecraft cryogenic feedlines and industrial hot/cold transfer

  10. Refuge alternatives relief valve testing and design

    PubMed Central

    Lutz, T.J.; Bissert, P.T.; Homce, G.T.; Yonkey, J.A.

    2016-01-01

    The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. PMID:28018003

  11. Refuge alternatives relief valve testing and design.

    PubMed

    Lutz, T J; Bissert, P T; Homce, G T; Yonkey, J A

    2016-10-01

    The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer's steel prefabricated RAs and had been adapted for use in one mine operator's built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer's specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster.

  12. OPSAID Initial Design and Testing Report.

    SciTech Connect

    Hurd, Steven A.; Stamp, Jason Edwin; Chavez, Adrian R.

    2007-11-01

    Process Control System (PCS) security is critical to our national security. Yet, there are a number of technological, economic, and educational impediments to PCS owners implementing effective security on their systems. OPSAID (Open PCS Security Architecture for Interoperable Design), a project sponsored by the US Department of Energy's Office of Electricity Delivery and Reliability, aims to address this issue through developing and testing an open source architecture for PCS security. Sandia National Laboratories, along with a team of PCS vendors and owners, have developed and tested this PCS security architecture. This report describes their progress to date.2 AcknowledgementsThe authors acknowledge and thank their colleagues for their assistance with the OPSAID project.Sandia National Laboratories: Alex Berry, Charles Perine, Regis Cassidy, Bryan Richardson, Laurence PhillipsTeumim Technical, LLC: Dave TeumimIn addition, the authors are greatly indebted to the invaluable help of the members of the OPSAID Core Team. Their assistance has been critical to the success and industry acceptance of the OPSAID project.Schweitzer Engineering Laboratory: Rhett Smith, Ryan Bradetich, Dennis GammelTelTone: Ori Artman Entergy: Dave Norton, Leonard Chamberlin, Mark AllenThe authors would like to acknowledge that the work that produced the results presented in this paper was funded by the U.S. Department of Energy/Office of Electricity Delivery and Energy Reliability (DOE/OE) as part of the National SCADA Test Bed (NSTB) Program. Executive SummaryProcess control systems (PCS) are very important for critical infrastructure and manufacturing operations, yet cyber security technology in PCS is generally poor. The OPSAID (Open PCS (Process Control System) Security Architecture for Interoperable Design) program is intended to address these security shortcomings by accelerating the availability and deployment of comprehensive security technology for PCS, both for existing PCS and

  13. Savonius wind turbines: Design and testing of unique blade designs

    NASA Astrophysics Data System (ADS)

    McPherson, Paul B.

    As the idea of implementing alternative energy systems into urbanized areas continues to gain popularity, there is a growing need to improve the efficiency of such systems. Therefore, the purpose of this research was to determine whether or not six unique blade designs, developed by the researcher, would lead to a more efficient vertical axis Savonius wind turbine. This report provides details regarding the study of aerodynamic forces, drag coefficients, and flow characteristics around each blade as well as information pertaining to the assembly and field testing of a turbine. The researcher began by conducting wind tunnel tests and computational fluid dynamic simulations on a single blade with the proposed designs. The data from these experiments was then used to calculate the driving and opposing forces and drag coefficients that would be present when each blade design is used in a fully assembled turbine. Lastly, the researcher determined the theoretical maximum efficiency of each turbine by multiplying the difference between the drag coefficients with the Betz Limit (4/27). Upon analyzing the results, the researcher discovered that the forces that were reported in the CFD analysis were more than double those measured in the wind tunnel. In addition, upon calculating the performance of each blade design when assembled into a full turbine, it was found that the turbines may not perform as well as the researcher initially expected; with only one having an efficiency of greater than 12%. However, because of the differences between the wind tunnel and CFD results, the researcher suggests that further experimentation and analysis needs to be completed to accurately justify the performance calculations.

  14. EFFICIENT HYDROLOGICAL TRACER-TEST DESIGN (EHTD ...

    EPA Pesticide Factsheets

    Hydrological tracer testing is the most reliable diagnostic technique available for establishing flow trajectories and hydrologic connections and for determining basic hydraulic and geometric parameters necessary for establishing operative solute-transport processes. Tracer-test design can be difficult because of a lack of prior knowledge of the basic hydraulic and geometric parameters desired and the appropriate tracer mass to release. A new efficient hydrologic tracer-test design (EHTD) methodology has been developed that combines basic measured field parameters (e.g., discharge, distance, cross-sectional area) in functional relationships that describe solute-transport processes related to flow velocity and time of travel. The new method applies these initial estimates for time of travel and velocity to a hypothetical continuously stirred tank reactor as an analog for the hydrologic flow system to develop initial estimates for tracer concentration and axial dispersion, based on a preset average tracer concentration. Root determination of the one-dimensional advection-dispersion equation (ADE) using the preset average tracer concentration then provides a theoretical basis for an estimate of necessary tracer mass.Application of the predicted tracer mass with the hydraulic and geometric parameters in the ADE allows for an approximation of initial sample-collection time and subsequent sample-collection frequency where a maximum of 65 samples were determined to

  15. Insights Gained from Testing Alternate Cell Designs

    SciTech Connect

    J. E. O'Brien; C. M. Stoots; J. S. Herring; G. K. Housley; M. S. Sohal; D. G. Milobar; Thomas Cable

    2009-09-01

    The Idaho National Laboratory (INL) has been researching the application of solid-oxide electrolysis cell for large-scale hydrogen production from steam over a temperature range of 800 to 900ºC. The INL has been testing various solid oxide cell designs to characterize their electrolytic performance operating in the electrolysis mode for hydrogen production. Some results presented in this report were obtained from cells, initially developed by the Forschungszentrum Jülich and now manufactured by the French ceramics firm St. Gobain. These cells have an active area of 16 cm2 per cell. They were initially developed as fuel cells, but are being tested as electrolytic cells in the INL test stands. The electrolysis cells are electrode-supported, with ~10 µm thick yttria-stabilized zirconia (YSZ) electrolytes, ~1400 µm thick nickel-YSZ steam-hydrogen electrodes, and manganite (LSM) air-oxygen electrodes. The experiments were performed over a range of steam inlet mole fractions (0.1 to 0.6), gas flow rates, and current densities (0 to 0.6 A/cm2). Steam consumption rates associated with electrolysis were measured directly using inlet and outlet dewpoint instrumentation. On a molar basis, the steam consumption rate is equal to the hydrogen production rate. Cell performance was evaluated by performing DC potential sweeps at 800, 850, and 900°C. The voltage-current characteristics are presented, along with values of area-specific resistance as a function of current density. Long-term cell performance is also assessed to evaluate cell degradation. Details of the custom single-cell test apparatus developed for these experiments are also presented. NASA, in conjunction with the University of Toledo, has developed another fuel cell concept with the goals of reduced weight and high power density. The NASA cell is structurally symmetrical, with both electrodes supporting the thin electrolyte and containing micro-channels for gas diffusion. This configuration is called a bi

  16. Testing and evaluation of a slot and tab construction technique for light-weight wood-fiber-based structural panels under bending

    Treesearch

    Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

    2015-01-01

    This paper presented construction and strain distributions for light-weight wood-fiber-based structural panels with tri-grid core made from phenolic impregnated laminated paper composites under bending. A new fastening configuration of slots in the faces and tabs on the core was applied to the face/core interfaces of the sandwich panel in addition to epoxy resin. Both...

  17. Some Investigations of the General Instability of Stiffened Metal Cylinders V : Stiffened Metal Cylinders Subjected to Pure Bending

    NASA Technical Reports Server (NTRS)

    Hoff, N J; Boley, Bruno A; Nardo, S V

    1938-01-01

    This report summarizes the work that has been carried on in the experimental investigation of the problem of general instability of stiffened metal cylinders subjected to pure bending at the C.I.T. This part of the investigation included tests of 46 sheet-covered specimens. The most significant result was the determination of a new design parameter for the case of a stiffened metal cylinder subjected to pure bending.

  18. 29 mm Diameter Test Target Design Report

    SciTech Connect

    Woloshun, Keith Albert; Dale, Gregory E.; Olivas, Eric Richard; Naranjo, Angela Carol; Romero, Frank Patrick

    2016-08-15

    The Northstar target for Mo99 production is made up of Mo100 disks in a stack separated by coolant gaps for helium flow. A number of targets have been tested at ANL for both production of Mo99 and for thermal-hydraulic performance. These have all been with a 12 mm diameter target, even while the production goals have increased the diameter to now 29 mm. A 29 mm diameter target has been designed that is consistent with the ANL beam capabilities and the capabilities of the helium circulation system currently in use at ANL. This target is designed for 500 μA at 35 MeV electrons. While the plant design calls for 42 MeV, the chosen design point is more favorable and higher power given the limits of the ANL accelerator. The intended beam spot size is 12 mm FWHM, but the thermal analysis presented herein conservatively assumed a 10 mm FWHM beam, which results in a 44% higher beam current density at beam center.

  19. Wind Turbine Blade Design for Subscale Testing

    NASA Astrophysics Data System (ADS)

    Hassanzadeh, Arash; Naughton, Jonathan W.; Kelley, Christopher L.; Maniaci, David C.

    2016-09-01

    Two different inverse design approaches are proposed for developing wind turbine blades for sub-scale wake testing. In the first approach, dimensionless circulation is matched for full scale and sub-scale wind turbine blades for equal shed vorticity in the wake. In the second approach, the normalized normal and tangential force distributions are matched for large scale and small scale wind turbine blades, as these forces determine the wake dynamics and stability. The two approaches are applied for the same target full scale turbine blade, and the shape of the blades are compared. The results show that the two approaches have been successfully implemented, and the designed blades are able to produce the target circulation and target normal and tangential force distributions.

  20. Testing for Spatial Isotropy Under General Designs.

    PubMed

    Maity, Arnab; Sherman, Michael

    2012-05-01

    Spatial modeling is typically composed of a specification of a mean function and a model for the correlation structure. A common assumption on the spatial correlation is that it is isotropic. This means that the correlation between any two observations depends only on the distance between those sites and not on their relative orientation. The assumption of isotropy is often made due to a simpler interpretation of correlation behavior and to an easier estimation problem under an assumed isotropy. The assumption of isotropy, however, can have serious deleterious effects when not appropriate. In this paper we formulate a test of isotropy for spatial observations located according to a general class of stochastic designs. Distribution theory of our test statistic is derived and we carry out extensive simulations which verify the efficacy of our approach. We apply our methodology to a data set on longleaf pine trees from an oldgrowth forest in the southern United States.

  1. Testing for Spatial Isotropy Under General Designs

    PubMed Central

    Maity, Arnab; Sherman, Michael

    2011-01-01

    Spatial modeling is typically composed of a specification of a mean function and a model for the correlation structure. A common assumption on the spatial correlation is that it is isotropic. This means that the correlation between any two observations depends only on the distance between those sites and not on their relative orientation. The assumption of isotropy is often made due to a simpler interpretation of correlation behavior and to an easier estimation problem under an assumed isotropy. The assumption of isotropy, however, can have serious deleterious effects when not appropriate. In this paper we formulate a test of isotropy for spatial observations located according to a general class of stochastic designs. Distribution theory of our test statistic is derived and we carry out extensive simulations which verify the efficacy of our approach. We apply our methodology to a data set on longleaf pine trees from an oldgrowth forest in the southern United States. PMID:22328802

  2. ACCESS: Design, Strategy, and Test Performance

    NASA Astrophysics Data System (ADS)

    Kaiser, Mary Elizabeth; Morris, M. J.; McCandliss, S. R.; Rauscher, B. J.; Kimble, R. A.; Kruk, J. W.; Wright, E. L.; Pelton, R. S.; Feldman, P. D.; Moos, H. W.; Riess, A. G.; Benford, D. J.; Foltz, R.; Gardner, J. P.; Mott, D. B.; Wen, Y.; Woodgate, B. E.; Bohlin, R.; Deustua, S. E.; Dixon, W. V.; Sahnow, D. J.; Kurucz, R. L.; Lampton, M.; Perlmutter, S.

    2013-01-01

    Improvements in the astrophysical flux scale are needed to answer fundamental scientific questions ranging from cosmology to stellar physics. In particular, the precise calibration of the flux scale across the visible-NIR bandpass is fundamental to the precise determination of dark energy parameters based on SNeIa photometry. ACCESS, Absolute Color Calibration Experiment for Standard Stars, is a series of rocket-borne sub-orbital missions and ground-based experiments that will enable improvements in the precision of the astrophysical flux scale through the transfer of absolute laboratory detector standards from the National Institute of Standards and Technology (NIST) to a network of stellar standards with a calibration accuracy of 1% and a spectral resolving power of 500 across the 0.35 to 1.7 micron bandpass. The telescope is a Dall-Kirkham Cassegrain with a 15.5-inch primary. The spectrograph is a Rowland circle design, with the grating operating as a low order (m=1-4) echelle, a Fery prism provides cross dispersion, and a HST/WFC3 heritage HAWAII-1R HgCdTe detector is used across the full spectral bandpass. The telescope mirrors have received their flight coatings. The flight detector and detector spare have been integrated with their electronics and flight mount. The controller electronics have been flight qualified. Vibration testing to launch loads and thermal vacuum testing of the detector, mount, and housing have been performed. Detector characterization testing is in progress (Morris et al.). Fabrication, integration, and automation of the ground-based calibration subsystems are also in progress. The ACCESS design, calibration strategy, and ground-based integration and test results will be presented. Launch is expected this year. NASA sounding rocket grant NNX08AI65G and DOE DE-FG02-07ER41506 support this work.

  3. Temperature buffer test design, instrumentation and measurements

    NASA Astrophysics Data System (ADS)

    Sandén, Torbjörn; Goudarzi, Reza; de Combarieu, Michel; Åkesson, Mattias; Hökmark, Harald

    The Temperature Buffer Test, TBT, is a heated full-scale field experiment carried out jointly by ANDRA and SKB at the SKB Äspö Hard Rock Laboratory in Southeast Sweden. An existing 8 m deep, 1.8 m diameter KBS-3-type deposition hole located at -420 m level has been selected for the test. The objectives are to improve the general understanding of Thermo-Hydro-Mechanical, THM, behavior of buffer materials submitted to severe thermal conditions with temperatures well over 100 °C during water uptake of partly saturated bentonite-based buffer materials, and to check, in due time, their properties after water saturation. The test includes two carbon steel heating canisters each 3 m high and 0.6 m diameter, surrounded by 0.6 m of buffer material. There is a 0.2 m thick sand shield between the upper heater and the surrounding bentonite, while the lower heater is surrounded by bentonite only. On top of the stack of bentonite blocks is a confining plug anchored to the rock. In the slot between buffer and rock wall is a sand filter equipped with pipes to control the water pressure at the boundary, which is seldom done with an EBS in situ experiment. Both heater mid-height planes are densely instrumented in order to follow, with direct or indirect methods, buffer THM evolution. Temperature, relative humidity, stress and pore pressure have been monitored since the test start in March 2003. Total water inflow is also monitored. Firstly, the present paper describes the test design, the instrumentation, the plug anchoring system and the system for water boundary pressure control. Second, having described the test, the paper shows different measurements that illustrate evolution of temperature, saturation, suction and swelling pressure in the upper and the lower buffer.

  4. Thermal static bending of deployable interlocked booms

    NASA Technical Reports Server (NTRS)

    Staugaitis, C. L.; Predmore, R. E.

    1973-01-01

    Metal ribbons processed with a heat-forming treatment are enabled to form tubelike structures when deployed from a roll. Deployable booms of this have been utilized for gravity-gradient stabilization on the RAE, ATS, and Nimbus D satellites. An experimental thermal-mechanics test apparatus was developed to measure the thermal static bending and twist of booms up to 3 meters long. The apparatus was calibrated by using the correlation between calculated and observed thermal bending of a seamless tube. Thermal static bending values of 16 interlocked deployable booms were observed to be within a factor of 2.5 of the values calculated from seamless-tube theory. Out-of-Sun-plane thermal bending was caused by complex heat transfer across the interlocked seam. Significant thermal static twisting was not observed.

  5. Solar Probe thermal shield design and testing

    NASA Technical Reports Server (NTRS)

    Millard, Jerry M.; Miyake, Robert N.; Rainen, Richard A.

    1992-01-01

    This paper discusses the major thermal shield subsystem development activities in support of the Solar Probe study being conducted at JPL. The Solar Probe spacecraft will travel to within 4 solar radii of the sun's center to perform fundamental experiments in space physics. Exposure to 2900 earth suns at perihelion requires the spacecraft to be protected within the shadow envelope of a protective shield. In addition, the mass loss rate off of the shield at elevated temperature must comply with plasma instrument requirements and has become the driver of the shield design. This paper will focus on the analytical design work to size the shield and control the shield mass loss rate for the various spacecraft options under study, the application of carbon-carbon materials for shield components, development and preparation of carbon-carbon samples for materials testing, and a materials testing program for carbon-carbon and tungsten alloys to investigate thermal/optical properties, mass loss (carbon-carbon only), material integrity, and high velocity impact behavior.

  6. Solar Probe thermal shield design and testing

    NASA Technical Reports Server (NTRS)

    Millard, Jerry M.; Miyake, Robert N.; Rainen, Richard A.

    1992-01-01

    This paper discusses the major thermal shield subsystem development activities in support of the Solar Probe study being conducted at JPL. The Solar Probe spacecraft will travel to within 4 solar radii of the sun's center to perform fundamental experiments in space physics. Exposure to 2900 earth suns at perihelion requires the spacecraft to be protected within the shadow envelope of a protective shield. In addition, the mass loss rate off of the shield at elevated temperature must comply with plasma instrument requirements and has become the driver of the shield design. This paper will focus on the analytical design work to size the shield and control the shield mass loss rate for the various spacecraft options under study, the application of carbon-carbon materials for shield components, development and preparation of carbon-carbon samples for materials testing, and a materials testing program for carbon-carbon and tungsten alloys to investigate thermal/optical properties, mass loss (carbon-carbon only), material integrity, and high velocity impact behavior.

  7. 49 CFR 178.33b-7 - Design qualification test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Specifications for Inside Containers, and Linings § 178.33b-7 Design qualification test. (a) Drop testing. (1) To...) Criteria for passing the drop test: The containers must not break or leak. (b) Design qualification testing... 49 Transportation 3 2012-10-01 2012-10-01 false Design qualification test. 178.33b-7 Section...

  8. 49 CFR 178.33b-7 - Design qualification test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Specifications for Inside Containers, and Linings § 178.33b-7 Design qualification test. (a) Drop testing. (1) To...) Criteria for passing the drop test: The containers must not break or leak. (b) Design qualification testing... 49 Transportation 3 2014-10-01 2014-10-01 false Design qualification test. 178.33b-7 Section...

  9. 49 CFR 178.33b-7 - Design qualification test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Specifications for Inside Containers, and Linings § 178.33b-7 Design qualification test. (a) Drop testing. (1) To...) Criteria for passing the drop test: The containers must not break or leak. (b) Design qualification testing... 49 Transportation 3 2013-10-01 2013-10-01 false Design qualification test. 178.33b-7 Section...

  10. Optimal Design of Tests with Dichotomous and Polytomous Items.

    ERIC Educational Resources Information Center

    Berger, Martijn P. F.

    1998-01-01

    Reviews some results on optimal design of tests with items of dichotomous and polytomous response formats and offers rules and guidelines for optimal test assembly. Discusses the problem of optimal test design for two optimality criteria. (Author/SLD)

  11. Degradation mechanisms and accelerated aging test design

    SciTech Connect

    Clough, R L; Gillen, K T

    1985-01-01

    The fundamental mechanisms underlying the chemical degradation of polymers can change as a function of environmental stress level. When this occurs, it greatly complicates any attempt to use accelerated tests for predicting long-term material degradation behaviors. Understanding how degradation mechanisms can change at different stress levels facilitates both the design and the interpretation of aging tests. Oxidative degradation is a predominant mechanism for many polymers exposed to a variety of different environments in the presence of air, and there are two mechanistic considerations which are widely applicable to material oxidation. One involves a physical process, oxygen diffusion, as a rate-limiting step. This mechanism can predominate at high stress levels. The second is a chemical process, the time-dependent decomposition of peroxide species. This leads to chain branching and can become a rate-controlling factor at lower stress levels involving time-scales applicable to use environments. The authors describe methods for identifying the operation of these mechanisms and illustrate the dramatic influence they can have on the degradation behaviors of a number of polymer types. Several commonly used approaches to accelerated aging tests are discussed in light of the behaviors which result from changes in degradation mechanisms. 9 references, 4 figures.

  12. Mechanical bending behaviour of composite T-beams

    NASA Astrophysics Data System (ADS)

    Silva, A.; Travassos, J.; de Freitas, M. M.; Mota Soares, C. M.

    A study of the design and mechanical behavior of co-cured T-beams subjected to very high loading is presented. The T-beams were made by press molding from pre-pregs of uni-directional glass or carbon fiber and glass fabric reinforced high performant epoxy matrix. Each type of beam was instrumented with strain gauges in the web and flange in order to carry out experimental four point bending tests. Analytical and numerical studies were also performed to compare experimental versus numerical and analytical results and to establish the suitability of a simplified bending theory for statically determinate composite beams constructed from laminated composite panels. The maximum carrying loads in the beam layers were evaluated experimentally and analytically using the Tsai-Wu failure criterion. Results showing the suitability of the simplified beam theory are presented and discussed.

  13. Occipital bending in depression.

    PubMed

    Maller, Jerome J; Thomson, Richard H S; Rosenfeld, Jeffrey V; Anderson, Rodney; Daskalakis, Zafiris J; Fitzgerald, Paul B

    2014-06-01

    There are reports of differences in occipital lobe asymmetry within psychiatric populations when compared with healthy control subjects. Anecdotal evidence and enlarged lateral ventricles suggests that there may also be a different pattern of curvature whereby one occipital lobe wraps around the other, termed 'occipital bending'. We investigated the prevalence of occipital bending in 51 patients with major depressive disorder (males mean age = 41.96 ± 14.00 years, females mean age = 40.71 ± 12.41 years) and 48 age- and sex-matched healthy control subjects (males mean age = 40.29 ± 10.23 years, females mean age = 42.47 ± 14.25 years) and found the prevalence to be three times higher among patients with major depressive disorder (18/51, 35.3%) when compared with control subjects (6/48, 12.5%). The results suggest that occipital bending is more common among patients with major depressive disorder than healthy subjects, and that occipital asymmetry and occipital bending are separate phenomena. Incomplete neural pruning may lead to the cranial space available for brain growth being restricted, or ventricular enlargement may exacerbate the natural occipital curvature patterns, subsequently causing the brain to become squashed and forced to 'wrap' around the other occipital lobe. Although the clinical implications of these results are unclear, they provide an impetus for further research into the relevance of occipital bending in major depression disorder. © The Author (2014). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Changes in bending stiffness and lumbar spine range of movement following lumbar mobilization and manipulation.

    PubMed

    Stamos-Papastamos, Nikolaos; Petty, Nicola J; Williams, Jonathan M

    2011-01-01

    The purpose of this study was to investigate the effects of lumbar rotational manipulation and lumbar central posteroanterior mobilization on lumbar bending stiffness and flexion and extension range of motion (ROM). A same-subject, repeated-measures, crossover design was used using 32 asymptomatic subjects (16 female and 16 male; mean [SD] age, 25.5 [4.5] years; weight, 65.7 [11.8] kg; and height, 1.70 [0.08] m). Each subject received mobilization or manipulation on 2 different occasions. Bending stiffness was calculated using a 3-point bending model using an electromagnetic tracking device and a force platform; lumbar flexion and extension ROM was measured using an electromagnetic tracking device. All variables were measured pre- and postintervention. Their effect was compared using paired t tests. Manipulation and mobilization did not significantly alter either bending stiffness or lumbar flexion and extension ROM (mobilization: P = .175, P = .613, and P = .535; manipulation: P = .973, P = .323, and P = .439). Bending stiffness changes were not correlated to changes in ROM (Pearson r for stiffness-flexion = -0.102, P = .586; Pearson r for stiffness-extension = 0.014, P = .941). Manipulation and mobilization had no significant effect on bending stiffness or flexion and extension ROM for this group of subjects. Some individual variations in effect were observed. Copyright © 2011 National University of Health Sciences. Published by Mosby, Inc. All rights reserved.

  15. Car drivers attend to different gaze targets when negotiating closed vs. open bends.

    PubMed

    Kandil, Farid I; Rotter, Alexander; Lappe, Markus

    2010-04-29

    On winding roads, car drivers have to control speed and steering angle in order to keep the car in an optimal lane position. Among the strategies proposed for steering regulation are the use of the tangent point, a geometrical method, and gaze sampling, in which retinal flow lines obtained by tracking a spot on the future road need to be assessed. Previous studies used a variety of scenarios (real-road vs. simulator) and different road designs (closed vs. open bends, different curvatures) and found results speaking in favor of either strategy. Here, we investigate what effects the openness of the bend, i.e. the sight distance of the driver, has on the percentage with which drivers use the tangent point. Six drivers drove a test car repeatedly through a series of twelve bends on real roads while their eye-movements were recorded. Results show that the reliance on the tangent point is generally high and increases with the closedness (shorter sight distances) of the bend and higher curvature. In open bends they alternatively look far into the straight road segments adjacent to the bend, but do not use gaze sampling.

  16. Learning Design at White Sands Test Facility

    NASA Technical Reports Server (NTRS)

    Grotewiel, Shane

    2010-01-01

    During the Fall of 2010, I spent my time at NASA White Sands Test Facility in Las Cruces, NM as an Undergraduate Student Research Program (USRP) Intern. During that time, I was given three projects to work on: Large Altitude Simulation System (LASS) basket strainer, log books, and the design of a case for touch screen monitors used for simulations. I spent most of my time on the LASS basket strainer. The LASS system has a water feed line with a basket strainer that filters out rust. In 2009, there were three misfires which cost approximately $27,000 and about 8% of the allotted time. The strainer was getting a large change in pressure that would result in a shutdown of the system. I have designed a new basket that will eliminate the large pressure change and it can be used with the old basket strainer housing. The LASS system has three steam generators (modules). Documents pertaining to these modules are stored electronically, and the majority of the documents are not able to be searched with keywords, so they have to be gone through one by one. I have come up with an idea on how to organize these files so that the Propulsion Department may efficiently search through the documents needed. Propulsion also has a LASS simulator that incorporates two touch screen monitors. Currently these monitors are in six foot by two foot metal cabinet on wheels. During simulation these monitors are used in the block house and need to be taken out of the block house when not in use. I have designed different options for hand held cases for storing and transporting the monitors in and out of the block house. The three projects previously mentioned demonstrate my contributions to the Propulsion Department and have taught me real world experience that is essential in becoming a productive engineer.

  17. A transparent bending-insensitive pressure sensor.

    PubMed

    Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

    2016-05-01

    Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

  18. A transparent bending-insensitive pressure sensor

    NASA Astrophysics Data System (ADS)

    Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

    2016-05-01

    Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

  19. Springback Control in Industrial Bending Operations: Assessing the Accuracy of Three Commercial FEA Codes

    NASA Astrophysics Data System (ADS)

    Welo, Torgeir; Granly, Bjørg M.; Elverum, Christer; Søvik, Odd P.; Sørbø, Steinar

    2011-05-01

    Over the past two decades, a quantum leap has been made in FE technology for metal forming applications, including methods, algorithms, models and hardware capabilities. A myriad of research articles reports on methodologies that provide excellent capabilities in reproducing springback obtained from physical experiments. However, it is felt that we are not yet to the point where current modeling practice provides satisfactory value to tool designers and manufacturing engineers, particularly when the results have to be available before the first piece of tool steel has been cut; the main reasons being lack of accuracy in predicting elastic springback. The main objective of the present work is to validate springback capabilities using a strategy that integrates industrial tool simulation practice with carefully controlled physical experiments conducted in an academic setting. An industry-like (rotary) draw bending machine has been built and equipped with advanced measurement capabilities. Extruded rectangular, hollow aluminum alloy AA6060 sections were heat treated to two different tempers to produce a range of material properties prior to forming into two different bending angles. The selected set-up represents a challenging benchmark due to tight-radius bending and complex contact conditions, meaning that elastic springback is resulting from interaction effects between excessive local cross-sectional distortions and global bending mechanisms. The material properties were obtained by tensile testing, curve-fitting data to a conventional isotropic Ludwik-type material model. The bending process was modeled in three different commercial FE codes following best practice, including LS-Dyna, Stampack and Abaqus (explicit). The springback analyses were done prior to bending tests as would be done in an industrial tool design process. After having completed the bending tests and carefully measured the released bend angle for the different combinations, the results were

  20. Advanced burner test reactor preconceptual design report.

    SciTech Connect

    Chang, Y. I.; Finck, P. J.; Grandy, C.; Cahalan, J.; Deitrich, L.; Dunn, F.; Fallin, D.; Farmer, M.; Fanning, T.; Kim, T.; Krajtl, L.; Lomperski, S.; Moisseytsev, A.; Momozaki, Y.; Sienicki, J.; Park, Y.; Tang, Y.; Reed, C.; Tzanos, C; Wiedmeyer, S.; Yang, W.; Chikazawa, Y.; JAEA

    2008-12-16

    advanced fuel cycle; (2) To qualify the transuranics-containing fuels and advanced structural materials needed for a full-scale ABR; and (3) To support the research, development and demonstration required for certification of an ABR standard design by the U.S. Nuclear Regulatory Commission. The ABTR should also address the following additional objectives: (1) To incorporate and demonstrate innovative design concepts and features that may lead to significant improvements in cost, safety, efficiency, reliability, or other favorable characteristics that could promote public acceptance and future private sector investment in ABRs; (2) To demonstrate improved technologies for safeguards and security; and (3) To support development of the U.S. infrastructure for design, fabrication and construction, testing and deployment of systems, structures and components for the ABRs. Based on these objectives, a pre-conceptual design of a 250 MWt ABTR has been developed; it is documented in this report. In addition to meeting the primary and additional objectives listed above, the lessons learned from fast reactor programs in the U.S. and worldwide and the operating experience of more than a dozen fast reactors around the world, in particular the Experimental Breeder Reactor-II have been incorporated into the design of the ABTR to the extent possible.

  1. Multiple-cladding fibers with reduced bend loss

    NASA Astrophysics Data System (ADS)

    Tomljenovic-Hanic, Snjezana; Bulla, Douglas A. P.; Ankiewicz, Adrian; Love, John D.; Bailey, Ron

    2007-04-01

    We demonstrate that a highly bend-resistant fiber can be realized. It is shown theoretically that, by introducing both depressed and elevated rings into the cladding, bending loss can be reduced significantly. A fiber based on this design has been fabricated and characterized as a first step toward achieving this goal. The results show that a multiple-cladding fiber is highly bend resistant when compared with the standard telecom single-mode fiber.

  2. Cricket antennae shorten when bending (Acheta domesticus L.).

    PubMed

    Loudon, Catherine; Bustamante, Jorge; Kellogg, Derek W

    2014-01-01

    Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to "unfold" and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head.

  3. Cricket antennae shorten when bending (Acheta domesticus L.)

    PubMed Central

    Loudon, Catherine; Bustamante, Jorge; Kellogg, Derek W.

    2014-01-01

    Insect antennae are important mechanosensory and chemosensory organs. Insect appendages, such as antennae, are encased in a cuticular exoskeleton and are thought to bend only between segments or subsegments where the cuticle is thinner, more flexible, or bent into a fold. There is a growing appreciation of the dominating influence of folds in the mechanical behavior of a structure, and the bending of cricket antennae was considered in this context. Antennae will bend or deflect in response to forces, and the resulting bending behavior will affect the sensory input of the antennae. In some cricket antennae, such as in those of Acheta domesticus, there are a large number (>100) of subsegments (flagellomeres) that vary in their length. We evaluated whether these antennae bend only at the joints between flagellomeres, which has always been assumed but not tested. In addition we questioned whether an antenna undergoes a length change as it bends, which would result from some patterns of joint deformation. Measurements using light microscopy and SEM were conducted on both male and female adult crickets (Acheta domesticus) with bending in four different directions: dorsal, ventral, medial, and lateral. Bending occurred only at the joints between flagellomeres, and antennae shortened a comparable amount during bending, regardless of sex or bending direction. The cuticular folds separating antennal flagellomeres are not very deep, and therefore as an antenna bends, the convex side (in tension) does not have a lot of slack cuticle to “unfold” and does not lengthen during bending. Simultaneously on the other side of the antenna, on the concave side in compression, there is an increasing overlap in the folded cuticle of the joints during bending. Antennal shortening during bending would prevent stretching of antennal nerves and may promote hemolymph exchange between the antenna and head. PMID:25018734

  4. Fluidized Bed Asbestos Sampler Design and Testing

    SciTech Connect

    Karen E. Wright; Barry H. O'Brien

    2007-12-01

    A large number of samples are required to characterize a site contaminated with asbestos from previous mine or other industrial operations. Current methods, such as EPA Region 10’s glovebox method, or the Berman Elutriator method are time consuming and costly primarily because the equipment is difficult to decontaminate between samples. EPA desires a shorter and less costly method for characterizing soil samples for asbestos. The objective of this was to design and test a qualitative asbestos sampler that operates as a fluidized bed. The proposed sampler employs a conical spouted bed to vigorously mix the soil and separate fine particulate including asbestos fibers on filters. The filters are then analyzed using transmission electron microscopy for presence of asbestos. During initial testing of a glass prototype using ASTM 20/30 sand and clay fines as asbestos surrogates, fine particulate adhered to the sides of the glass vessel and the tubing to the collection filter – presumably due to static charge on the fine particulate. This limited the fines recovery to ~5% of the amount added to the sand surrogate. A second prototype was constructed of stainless steel, which improved fines recovery to about 10%. Fines recovery was increased to 15% by either humidifying the inlet air or introducing a voltage probe in the air space above the sample. Since this was not a substantial improvement, testing using the steel prototype proceeded without using these techniques. Final testing of the second prototype using asbestos suggests that the fluidized bed is considerably more sensitive than the Berman elutriator method. Using a sand/tremolite mixture with 0.005% tremolite, the Berman elutriator did not segregate any asbestos structures while the fluidized bed segregated an average of 11.7. The fluidized bed was also able to segregate structures in samples containing asbestos at a 0.0001% concentration, while the Berman elutriator method did not detect any fibers at this

  5. Prediction and measurement of composite tube twist and bending due to thermal loading

    NASA Astrophysics Data System (ADS)

    Bluth, A. Marcel; Tucker, James R.; Thompson, Troy

    2013-09-01

    Composite materials are applied in precision optical metering structures because of their low thermal expansion properties in concert with high specific stiffness. Twisting and bending of long composite tubes, such as the secondary mirror support structure for the JWST telescope, requires control and verification. A stochastic modeling method was applied that simulates the manufacturing process variability and estimates ranges for expected twist and bend over the tube length from ambient to cryogenic temperatures. A development strut for the JWST secondary mirror support structure was fabricated and a metrology system was designed and implemented that measured the bend and twist response from ambient to 30 K. Modeling methods and predictions are outlined. The test metrology and results are summarized, along with a comparison between test and prediction.

  6. Single Event Testing on Complex Devices: Test Like You Fly versus Test-Specific Design Structures

    NASA Technical Reports Server (NTRS)

    Berg, Melanie; LaBel, Kenneth A.

    2014-01-01

    We present a framework for evaluating complex digital systems targeted for harsh radiation environments such as space. Focus is limited to analyzing the single event upset (SEU) susceptibility of designs implemented inside Field Programmable Gate Array (FPGA) devices. Tradeoffs are provided between application-specific versus test-specific test structures.

  7. Test Design Project: Studies in Test Bias. Annual Report.

    ERIC Educational Resources Information Center

    McArthur, David

    Item bias in a multiple-choice test can be detected by appropriate analyses of the persons x items scoring matrix. This permits comparison of groups of examinees tested with the same instrument. The test may be biased if it is not measuring the same thing in comparable groups, if groups are responding to different aspects of the test items, or if…

  8. On-line fuzzy logic control of tube bending

    NASA Astrophysics Data System (ADS)

    Lieh, Junghsen; Li, Wei Jie

    2005-11-01

    This paper describes the simulation and on-line fuzzy logic control of tube bending. By combining elasticity and plasticity theories, a conventional model was developed. The results from simulation were compared with those obtained from testing. The experimental data reveal that there exists certain level of uncertainty and nonlinearity in tube bending, and its variation could be significant. To overcome this, a on-line fuzzy logic controller with self-tuning capabilities was designed. The advantages of this on-line system are (1) its computational requirement is simple in comparison with more algorithmic-based controllers, and (2) the system does not need prior knowledge of material characteristics. The device includes an AC motor, a servo controller, a forming mechanism, a 3D optical sensor, and a microprocessor. This automated bending machine adopts primary and secondary errors between the actual response and desired output to conduct on-line rule reasoning. Results from testing show that the spring back angle can be effectively compensated by the self- tuning fuzzy system in a real-time fashion.

  9. Optimal Test Design with Rule-Based Item Generation

    ERIC Educational Resources Information Center

    Geerlings, Hanneke; van der Linden, Wim J.; Glas, Cees A. W.

    2013-01-01

    Optimal test-design methods are applied to rule-based item generation. Three different cases of automated test design are presented: (a) test assembly from a pool of pregenerated, calibrated items; (b) test generation on the fly from a pool of calibrated item families; and (c) test generation on the fly directly from calibrated features defining…

  10. Optimal Test Design with Rule-Based Item Generation

    ERIC Educational Resources Information Center

    Geerlings, Hanneke; van der Linden, Wim J.; Glas, Cees A. W.

    2013-01-01

    Optimal test-design methods are applied to rule-based item generation. Three different cases of automated test design are presented: (a) test assembly from a pool of pregenerated, calibrated items; (b) test generation on the fly from a pool of calibrated item families; and (c) test generation on the fly directly from calibrated features defining…

  11. Design, fabrication and test of block 4 design solar cell modules. Part 2: Residential module

    NASA Technical Reports Server (NTRS)

    Jester, T. L.

    1982-01-01

    Design, fabrication and test of the Block IV residential load module are reported. Design changes from the proposed module design through three iterations to the discontinuance of testing are outlined.

  12. High-efficiency beam bending using graded photonic crystals.

    PubMed

    Oner, B B; Turduev, M; Kurt, H

    2013-05-15

    We explore beam-bending properties of graded index (GRIN) waveguide with hyperbolic secant profile. The transmission efficiency and bandwidth features are extracted for GRIN photonic crystal (PC) media composed of dielectric rods. Light guiding performance of the GRIN PC medium is analyzed for 90° and 180° waveguide bends. The finite-difference time-domain method is deployed to investigate the performance of the designed GRIN waveguides. By the help of proposed photonic configuration, bending of light is achieved with a high efficiency within a broad bandwidth, which promotes the use of GRIN PC structures for efficient light-bending purposes.

  13. 46 CFR 61.40-3 - Design verification testing.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Design verification testing. 61.40-3 Section 61.40-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND INSPECTIONS Design Verification and Periodic Testing of Vital System Automation § 61.40-3 Design...

  14. 46 CFR 61.40-3 - Design verification testing.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Design verification testing. 61.40-3 Section 61.40-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND INSPECTIONS Design Verification and Periodic Testing of Vital System Automation § 61.40-3 Design...

  15. 46 CFR 61.40-3 - Design verification testing.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Design verification testing. 61.40-3 Section 61.40-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND INSPECTIONS Design Verification and Periodic Testing of Vital System Automation § 61.40-3 Design...

  16. 46 CFR 61.40-3 - Design verification testing.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Design verification testing. 61.40-3 Section 61.40-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND INSPECTIONS Design Verification and Periodic Testing of Vital System Automation § 61.40-3 Design...

  17. 46 CFR 61.40-3 - Design verification testing.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Design verification testing. 61.40-3 Section 61.40-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PERIODIC TESTS AND INSPECTIONS Design Verification and Periodic Testing of Vital System Automation § 61.40-3 Design...

  18. 49 CFR 178.33b-7 - Design qualification test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Design qualification test. 178.33b-7 Section 178... PACKAGINGS Specifications for Inside Containers, and Linings § 178.33b-7 Design qualification test. (a) Drop..., each new design must be drop tested as follows: Three groups of twenty-five filled containers must...

  19. Affordable Acoustic Disdrometer: Design, Calibration, Tests

    NASA Astrophysics Data System (ADS)

    van de Giesen, N.; Degen, C.; Hut, R.

    2009-12-01

    It would be a hydrological understatement to say that measuring rainfall correctly is important. Recent years have seen important lowering of the costs of raingauges capable of measuring rainfall intensities. Such raingauges are typically tipping bucket raingauges, connected to an event logger. Costs for such a raingauge are about 100. Accuracy is not always very high, especially during high intensity storms. The moving parts make them vulnerable to slight disruptions such as insects. We set out to design a raingauge without moving parts and at a better price/quality ratio than existing raingauges. After testing several potential candidates, we settled on a very simple piezo ceramic element, which measures the impact of single drops. Such an element costs around 1. The impact of each drop causes an acoustic signal that is transformed into a voltage. A typical impact gives an upswing of up to 1 V and the ringing lasts about 50 ms. With a surface area of about 20 cm2, there is almost never overlap between the signals of different drops. The basic assumption is that each drop will have reached terminal velocity and that the total energy of the impact can, thereby, be related to drop size. We calibrated this acoustic disdrometer by letting drops of different size fall on the disdrometer. A very encouraging calibration curve was obtained in this way. Further testing consisted of comparisons during rainstorms between the acoustic disdrometer and standard tipping bucket raingauges. During intensive storms, the acoustic disdrometer gave results that were very close to those of a nearby totaling raingauge. The signal of the tipping bucket raingauges was clearly saturated as these were not capable of keeping up with the rain. During low intensity events, tipping bucket raingauges performed better as drops too small to detect by the acoustic disdrometer became a significant part of the total rainfall. In first instance, a simple MP3 player with recording functionality ($50

  20. Behavior of sandwich panels subjected to bending fatigue, axial compression loading and in-plane bending

    NASA Astrophysics Data System (ADS)

    Mathieson, Haley Aaron

    This thesis investigates experimentally and analytically the structural performance of sandwich panels composed of glass fibre reinforced polymer (GFRP) skins and a soft polyurethane foam core, with or without thin GFRP ribs connecting skins. The study includes three main components: (a) out-of-plane bending fatigue, (b) axial compression loading, and (c) in-plane bending of sandwich beams. Fatigue studies included 28 specimens and looked into establishing service life (S-N) curves of sandwich panels without ribs, governed by soft core shear failure and also ribbed panels governed by failure at the rib-skin junction. Additionally, the study compared fatigue life curves of sandwich panels loaded under fully reversed bending conditions (R=-1) with panels cyclically loaded in one direction only (R=0) and established the stiffness degradation characteristics throughout their fatigue life. Mathematical models expressing fatigue life and stiffness degradation curves were calibrated and expanded forms for various loading ratios were developed. Approximate fatigue thresholds of 37% and 23% were determined for non-ribbed panels loaded at R=0 and -1, respectively. Digital imaging techniques showed significant shear contribution significantly (90%) to deflections if no ribs used. Axial loading work included 51 specimens and examined the behavior of panels of various lengths (slenderness ratios), skin thicknesses, and also panels of similar length with various rib configurations. Observed failure modes governing were global buckling, skin wrinkling or skin crushing. In-plane bending involved testing 18 sandwich beams of various shear span-to-depth ratios and skin thicknesses, which failed by skin wrinkling at the compression side. The analytical modeling components of axially loaded panels include; a simple design-oriented analytical failure model and a robust non-linear model capable of predicting the full load-displacement response of axially loaded slender sandwich panels

  1. Characterization of the bending stiffness of large space structure joints

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey

    1989-01-01

    A technique for estimating the bending stiffness of large space structure joints is developed and demonstrated for an erectable joint concept. Experimental load-deflection data from a three-point bending test was used as input to solve a closed-form expression for the joint bending stiffness which was derived from linear beam theory. Potential error sources in both the experimental and analytical procedures are identified and discussed. The bending stiffness of a mechanically preloaded erectable joint is studied at three applied moments and seven joint orientations. Using this technique, the joint bending stiffness was bounded between 6 and 17 percent of the bending stiffness of the graphite/epoxy strut member.

  2. Pitting and Bending Fatigue Evaluations of a New Case-Carburized Gear Steel

    NASA Technical Reports Server (NTRS)

    Krantz, Timothy; Tufts, Brian

    2007-01-01

    The power density of a gearbox is an important consideration for many applications and is especially important for gearboxes used on aircraft. One approach to improving power density of gearing is to improve the steel properties by design of the alloy. The alloy tested in this work was designed to be case-carburized with surface hardness of Rockwell C66 after hardening. Test gear performance was evaluated using surface fatigue tests and single-tooth bending fatigue tests. The performance of gears made from the new alloy was compared to the performance of gears made from two alloys currently used for aviation gearing. The new alloy exhibited significantly better performance in surface fatigue testing, demonstrating the value of the improved properties in the case layer. However, the alloy exhibited lesser performance in single-tooth bending fatigue testing. The fracture toughness of the tested gears was insufficient for use in aircraft applications as judged by the behavior exhibited during the single tooth bending tests. This study quantified the performance of the new alloy and has provided guidance for the design and development of next generation gear steels.

  3. 10 CFR 60.142 - Design testing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... construction, a program for in situ testing of such features as borehole and shaft seals, backfill, and the thermal interaction effects of the waste packages, backfill, rock, and groundwater shall be conducted. (b) The testing shall be initiated as early as is practicable. (c) A backfill test section shall...

  4. 10 CFR 60.142 - Design testing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... construction, a program for in situ testing of such features as borehole and shaft seals, backfill, and the thermal interaction effects of the waste packages, backfill, rock, and groundwater shall be conducted. (b) The testing shall be initiated as early as is practicable. (c) A backfill test section shall...

  5. 10 CFR 60.142 - Design testing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... construction, a program for in situ testing of such features as borehole and shaft seals, backfill, and the thermal interaction effects of the waste packages, backfill, rock, and groundwater shall be conducted. (b) The testing shall be initiated as early as is practicable. (c) A backfill test section shall...

  6. HiMAT aerodynamic design and flight test experience

    NASA Technical Reports Server (NTRS)

    Matheny, N. W.; Panageas, G. N.

    1981-01-01

    Consideration is given to the design phase of the highly maneuverable aircraft technology program. Design objectives are examined, noting full-scale design and the remotely piloted research vehicle. Attention is given to subsonic, transonic, and supersonic design. Design results are discussed with reference to aerodynamic efficiency, aeroelastic tailoring, and the flight test program.

  7. Design and performance test of spacecraft test and operation software

    NASA Astrophysics Data System (ADS)

    Wang, Guohua; Cui, Yan; Wang, Shuo; Meng, Xiaofeng

    2011-06-01

    Main test processor (MTP) software is the key element of Electrical Ground Support Equipment (EGSE) for spacecraft test and operation used in the Chinese Academy of Space Technology (CAST) for years without innovation. With the increasing demand for a more efficient and agile MTP software, the new MTP software was developed. It adopts layered and plug-in based software architecture, whose core runtime server provides message queue management, share memory management and process management services and forms the framework for a configurable and open architecture system. To investigate the MTP software's performance, the test case of network response time, test sequence management capability and data-processing capability was introduced in detail. Test results show that the MTP software is common and has higher performance than the legacy one.

  8. Statistical mechanics of bend flexoelectricity and the twist-bend phase in bent-core liquid crystals.

    PubMed

    Shamid, Shaikh M; Dhakal, Subas; Selinger, Jonathan V

    2013-05-01

    We develop a Landau theory for bend flexoelectricity in liquid crystals of bent-core molecules. In the nematic phase of the model, the bend flexoelectric coefficient increases as we reduce the temperature toward the nematic to polar phase transition. At this critical point, there is a second-order transition from high-temperature uniform nematic phase to low-temperature nonuniform polar phase composed of twist-bend or splay-bend deformations. To test the predictions of Landau theory, we perform Monte Carlo simulations to find the director and polarization configurations as functions of temperature, applied electric field, and interaction parameters.

  9. Bending Gold Nanorods with Light.

    PubMed

    Babynina, Anastasia; Fedoruk, Michael; Kühler, Paul; Meledin, Alexander; Döblinger, Markus; Lohmüller, Theobald

    2016-10-12

    V-shaped gold nanoantennas are the functional components of plasmonic metasurfaces, which are capable of manipulating light in unprecedented ways. Designing a metasurface requires the custom arrangement of individual antennas with controlled shape and orientation. Here, we show how highly crystalline gold nanorods in solution can be bent, one-by-one, into a V-shaped geometry and printed to the surface of a solid support through a combination of plasmonic heating and optical force. Significantly, we demonstrate that both the bending angle and the orientation of each rod-antenna can be adjusted independent from each other by tuning the laser intensity and polarization. This approach is applicable for the patterning of V-shaped plasmonic antennas on almost any substrate, which holds great potential for the fabrication of ultrathin optical components and devices.

  10. NASA Now: Engineering Design: Wind Tunnel Testing

    NASA Image and Video Library

    Dr. Norman W. Schaeffler, a NASA aerospace research engineer, describes how wind tunnels work and how aircraft designers use them to understand aerodynamic forces at low speeds. Learn the advantage...

  11. Bending the Rings

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Saturn's rings appear strangely warped in this view of the rings seen through the upper Saturn atmosphere.

    The atmosphere acts like a lens in refracting (bending) the light reflected from the rings. As the rings pass behind the overexposed limb (edge) of Saturn as seen from Cassini, the ring structure appears to curve downward due to the bending of the light as it passes through the upper atmosphere.

    This image was obtained using a near-infrared filter. The filter samples a wavelength where methane gas does not absorb light, thus making the far-off rings visible through the upper atmosphere.

    By comparing this image to similar ones taken using filters where methane gas does absorb, scientists can estimate the vertical profile of haze and the abundance of methane in Saturn's high atmosphere.

    The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 14, 2005, through a filter sensitive to wavelengths of infrared light centered at 938 nanometers and at a distance of approximately 197,000 kilometers (123,000 miles) from Saturn. The image scale is 820 meters (2,680 feet) per pixel.

  12. An optical fiber Fabry-Perot flow measurement technology based on partial bend structure

    NASA Astrophysics Data System (ADS)

    Yang, Huijia; Jiang, Junfeng; Zhang, Xuezhi; Pan, Yuheng; Zhu, Wanshan; Zhou, Xiang; Liu, Tiegen

    2016-08-01

    An optical fiber Fabry-Perot (F-P) flow measurement technology is presented, which is based on partial bend structure. A 90° partial bend structure is designed to achieve the non-probe flow measurement with a pressure difference. The fluid simulation results of partial bend structure show that the error of the pressure difference is below 0.05 kPa during steady flow. The optical fiber F-P sensor mounted on the elbow with pressure test accuracy of 1% full scale is used to measure the fluid flow. Flow test results show that when the flow varies from 1 m3/h to 6.5 m3/h at ambient temperature of 25 °C, the response time is 1 s and the flow test accuracy is 4.5% of the F-P flow test system, proving that the F-P flow test method based on partial bend structure can be used in fluid flow measurement.

  13. An optical fiber Fabry-Perot flow measurement technology based on partial bend structure.

    PubMed

    Yang, Huijia; Jiang, Junfeng; Zhang, Xuezhi; Pan, Yuheng; Zhu, Wanshan; Zhou, Xiang; Liu, Tiegen

    2016-08-01

    An optical fiber Fabry-Perot (F-P) flow measurement technology is presented, which is based on partial bend structure. A 90° partial bend structure is designed to achieve the non-probe flow measurement with a pressure difference. The fluid simulation results of partial bend structure show that the error of the pressure difference is below 0.05 kPa during steady flow. The optical fiber F-P sensor mounted on the elbow with pressure test accuracy of 1% full scale is used to measure the fluid flow. Flow test results show that when the flow varies from 1 m(3)/h to 6.5 m(3)/h at ambient temperature of 25 °C, the response time is 1 s and the flow test accuracy is 4.5% of the F-P flow test system, proving that the F-P flow test method based on partial bend structure can be used in fluid flow measurement.

  14. FASTER Test Reactor Preconceptual Design Report

    SciTech Connect

    Grandy, C.; Belch, H.; Brunett, A. J.; Heidet, F.; Hill, R.; Hoffman, E.; Jin, E.; Mohamed, W.; Moisseytsev, A.; Passerini, S.; Sienicki, J.; Sumner, T.; Vilim, R.; Hayes, S.

    2016-03-31

    The FASTER test reactor plant is a sodium-cooled fast spectrum test reactor that provides high levels of fast and thermal neutron flux for scientific research and development. The 120MWe FASTER reactor plant has a superheated steam power conversion system which provides electrical power to a local grid allowing for recovery of operating costs for the reactor plant.

  15. Bending Strength of Shallow Glued-Laminated Beams of a Uniform Grade.

    DTIC Science & Technology

    1981-04-01

    study AITC beams with knots. Of the 90 Douglas-timber have concentrated on better 117-76 (1) listed design bending fir beams tested. 30 had 8 lamina...SPIB) rules (16) by SPIB supervised as described by the IKIIG concept. L3, respectively. Quality of the ten- mill graders AITC representatives Through...IG theory predicted lumber as No. 2D at the plant. AITC modulus of rupture (MOR) and that the selected test beam combina- representatives and a plant

  16. A Comparison of Testlet-Based Test Designs for Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Schnipke, Deborah L.; Reese, Lynda M.

    Two-stage and multistage test designs provide a way of roughly adapting item difficulty to test-taker ability. All test takers take a parallel stage-one test, and, based on their scores, they are routed to tests of different difficulty levels in subsequent stages. These designs provide some of the benefits of standard computerized adaptive testing…

  17. Interface Design in Computer-Based Language Testing.

    ERIC Educational Resources Information Center

    Fulcher, Glenn

    2003-01-01

    Describes a three-phase process model for interface design, drawing on practices developed in the software industry and adapting them for computer-based languages tests. Describes good practice in initial design, emphasizes the importance of usability testing, and argues that only through following a principled approach to interface design can the…

  18. Light bending in radiation background

    SciTech Connect

    Kim, Jin Young; Lee, Taekoon E-mail: tlee@kunsan.ac.kr

    2014-01-01

    We consider the velocity shift of light in presence of radiation emitted by a black body. Within geometric optics formalism we calculate the bending angle of a light ray when there is a gradient in the energy density. We model the bending for two simplified cases. The bending angle is proportional to the inverse square power of the impact parameter (∝1/b{sup 2}) when the dilution of energy density is spherically symmetric. The bending angle is inversely proportional to the impact parameter (∝1/b) when the energy density dilutes cylindrically. Assuming that a neutron star is an isothermal black body, we estimate the order of magnitude for such bending angle and compare it with the bending angle by magnetic field.

  19. Dynamic (Vibration) Testing: Design-Certification of Aerospace System

    NASA Technical Reports Server (NTRS)

    Aggarwal, Pravin K.

    2010-01-01

    Various types of dynamic testing of structures for certification purposes are described, including vibration, shock and acoustic testing. Modal testing is discussed as it frequently complements dynamic testing and is part of the structural verification/validation process leading up to design certification. Examples of dynamic and modal testing are presented as well as the common practices, procedures and standards employed.

  20. Test Design Project: Studies in Test Adequacy. Annual Report.

    ERIC Educational Resources Information Center

    Wilcox, Rand R.

    These studies in test adequacy focus on two problems: procedures for estimating reliability, and techniques for identifying ineffective distractors. Fourteen papers are presented on recent advances in measuring achievement (a response to Molenaar); "an extension of the Dirichlet-multinomial model that allows true score and guessing to be…

  1. APEX 3D Propeller Test Preliminary Design

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    2002-01-01

    A low Reynolds number, high subsonic mach number flight regime is fairly uncommon in aeronautics. Most flight vehicles do not fly under these aerodynamic conditions. However, recently there have been a number of proposed aircraft applications (such as high altitude observation platforms and Mars aircraft) that require flight within this regime. One of the main obstacles to flight under these conditions is the ability to reliably generate sufficient thrust for the aircraft. For a conventional propulsion system, the operation and design of the propeller is the key aspect to its operation. Due to the difficulty in experimentally modeling the flight conditions in ground-based facilities, it has been proposed to conduct propeller experiments from a high altitude gliding platform (APEX). A preliminary design of a propeller experiment under the low Reynolds number, high mach number flight conditions has been devised. The details of the design are described as well as the potential data that will be collected.

  2. Cost effective dynamic design and test requirements for Shuttle payloads

    NASA Technical Reports Server (NTRS)

    Stahle, C. V.; Gongloff, H. R.; Bangs, W. F.

    1975-01-01

    The results of a study examining current spacecraft dynamic design and test requirements for the cost effective design and development of Shuttle payloads are presented. Dynamic environments, payload configurations, design/test requirements, test levels, assembly level of testing, simulation methods, prototype role, load limiting, test facilities, and flight measurements are discussed as they relate to the development of a cost effective design and test philosophy for Shuttle Spacelab payloads. It is concluded that changes to current design/test practices will minimize long range payload costs. However, changes to current practices need be quantitatively evaluated before an orderly progression to more cost effective methods can be achieved without undue risk of mission failures. Of major importance is optimization of test levels and plans for payloads and payload subsystems which will result in minimum project costs.

  3. Accelerated Reliability Testing Utilizing Design of Experiments

    DTIC Science & Technology

    1993-12-01

    hat to Measure ............................... 23 b. Identify Stresses ................................ 24 c . Stress Levels...36 c . Test Time ................................... 48 d. Trade Off Analysis .............................. 56 3. A nalysis...79 2. Exam ple 2 . ..................................... 92 3. Exam ple 3 . .................................... 102 C . Conclusion

  4. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    NASA Astrophysics Data System (ADS)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2017-02-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  5. Bending Behavior of Porous Sintered Stainless Steel Fiber Honeycombs

    NASA Astrophysics Data System (ADS)

    Zou, Shuiping; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-12-01

    A novel porous honeycomb-type substrate has been developed using solid-state sintering stainless steel fibers. The porous sintered stainless steel fiber honeycombs (PSSSFH) are composed of a skeleton of sintered stainless steel fibers, three-dimensionally interconnected porous structures and multiple parallel microchannels. The bending behavior of the PSSSFH is investigated using three-point bending tests. Four stages, including an elastic stage, a yielding stage with a plateau, a hardening stage and a failure stage, are observed during the bending process of the PSSSFH. In the initial yielding stage, the bending forces increase slowly with displacement increasing, and then a yielding plateau follows, which is unique compared with other porous materials. Moreover, the structure parameters of the PSSSFH are varied to investigate the influence on the bending strength. It is determined that the multiple parallel microchannels can enhance the bending strength of porous stainless steel fiber sintered substrates (PSSFSS) and do not influence the variation trend of bending strength of PSSFSS with porosity increasing. The open ratio is conducive to increasing the bending strength, and the microchannel diameters ranging from 0.5 mm to 1.5 mm have little influence on the bending strength. In addition, both the increasing of sintering temperature and sintering time can strengthen the PSSSFH.

  6. Impedance-matching acoustic bend composed of perforated plates and side pipes

    NASA Astrophysics Data System (ADS)

    Yang, Yuzhen; Jia, Han; Lu, Wenjia; Sun, Zhaoyong; Yang, Jun

    2017-08-01

    In this article, we propose a design for an impedance-matching acoustic bend. The bending structure is composed of sub-wavelength unit cells containing perforated plates and side pipes that allow the mass density and the bulk modulus of each unit cell to be tuned simultaneously. The refractive index and the impedance of the acoustic bend can therefore be modulated simultaneously to guarantee both the bending effect and high acoustic transmission. The results of simulation of the sound pressure field distribution show that the bending effect of the proposed impedance-matching acoustic bend is very good. Transmission spectra are calculated for both the impedance-matching acoustic bend and an acoustic bend composed of the perforated plates alone for comparison. The results indicate that the impedance-matching acoustic bend successfully improves the impedance ratio while also obviously increasing the transmission.

  7. Design manual: Oxygen Thermal Test Article (OTTA)

    NASA Technical Reports Server (NTRS)

    Chronic, W. L.; Baese, C. L.; Conder, R. L.

    1974-01-01

    The characteristics of a cryogenic tank for storing liquid hydrogen, nitrogen, oxygen, methane, or helium for an extended period of time with minimum losses are discussed. A description of the tank and control module, assembly drawings and details of major subassemblies, specific requirements controlling development of the system, thermal concept considerations, thermal analysis methods, and a record of test results are provided. The oxygen thermal test article thermal protection system has proven that the insulation system for cryogenic vessels is effective.

  8. Engineering and Design: Laboratory Investigations and Testing

    DTIC Science & Technology

    2007-11-02

    Requirements for Hazardous, Toxic, and Radioactive Waste (HTRW) and Ordnance and Explosive Waste (OEW) Activities . b. ER 1110-1-261, Quality Assurance of...Laboratory Testing Procedures. c. ER 1110-1-263, Chemical Data Quality Management for Hazardous Waste Remedial Activities . d. ER 1110-1-2002, Cement...Slag, and Pozzolan Acceptance Testing. e. ER 1110-2-8154, Water Quality Management at Corps Civil Works Projects. f. ER 200-2-3, Environmental

  9. An Optimal Design Approach to Criterion-Referenced Computerized Testing

    ERIC Educational Resources Information Center

    Wiberg, Marie

    2003-01-01

    A criterion-referenced computerized test is expressed as a statistical hypothesis problem. This admits that it can be studied by using the theory of optimal design. The power function of the statistical test is used as a criterion function when designing the test. A formal proof is provided showing that all items should have the same item…

  10. A Psychological Measurement of Student Testing Design Preferences.

    ERIC Educational Resources Information Center

    Shukla, P. K.; Bruno, James

    An analytical technique from the field of market research called conjoint analysis was applied to a psychological measurement of student testing design preferences. Past concerns with testing design are reviewed, and a newer approach to testing is identified--the modified confidence weighted-admissible probability measurement (MCW-APM) test…

  11. 49 CFR 178.33b-7 - Design qualification test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Design qualification test. 178.33b-7 Section 178... Specifications for Inside Containers, and Linings § 178.33b-7 Design qualification test. (a) Drop testing. (1) To ensure that creep does not affect the ability of the container to retain the contents, each new...

  12. Test Designers Tap Students for Feedback

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    Pondering a math problem while she swings her sneakered feet from a chair, 12-year-old Andrea Guevara is helping researchers design an assessment that will shape the learning of 19 million students. The 8th grader, who came to the United States from Ecuador three years ago, is trying out two ways of providing English-language support on a…

  13. Test Designers Tap Students for Feedback

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2012-01-01

    Pondering a math problem while she swings her sneakered feet from a chair, 12-year-old Andrea Guevara is helping researchers design an assessment that will shape the learning of 19 million students. The 8th grader, who came to the United States from Ecuador three years ago, is trying out two ways of providing English-language support on a…

  14. Creating Ribo-T: (Design, Build, Test)n.

    PubMed

    Carlson, Erik D

    2015-11-20

    Engineering biology is especially challenging given our relatively poor ability to rationally design within life's complex design landscape. Thus, moving through the engineering "design, build, test" cycle multiple times accumulates system knowledge and hopefully yields a successful design. Here I discuss the engineering process behind our recently published work creating a ribosome with tethered subunits, Ribo-T.

  15. Bending strength of piezoelectric ceramics and single crystals for multifunctional load-bearing applications.

    PubMed

    Anton, Steven R; Erturk, Alper; Inman, Daniel

    2012-06-01

    The topic of multifunctional material systems using active or smart materials has recently gained attention in the research community. Multifunctional piezoelectric systems present the ability to combine multiple functions into a single active piezoelectric element, namely, combining sensing, actuation, or energy conversion ability with load-bearing capacity. Quantification of the bending strength of various piezoelectric materials is, therefore, critical in the development of load-bearing piezoelectric systems. Three-point bend tests are carried out on a variety of piezoelectric ceramics including soft monolithic piezoceramics (PZT-5A and PZT-5H), hard monolithic ceramics (PZT-4 and PZT-8), single-crystal piezoelectrics (PMN-PT and PMN-PZT), and commercially packaged composite devices (which contain active PZT-5A layers). A common 3-point bend test procedure is used throughout the experimental tests. The bending strengths of these materials are found using Euler-Bernoulli beam theory to be 44.9 MPa for PMN-PZT, 60.6 MPa for PMN-PT, 114.8 MPa for PZT- 5H, 123.2 MPa for PZT-4, 127.5 MPa for PZT-8, 140.4 MPa for PZT-5A, and 186.6 MPa for the commercial composite. The high strength of the commercial configuration is a result of the composite structure that allows for shear stresses on the surfaces of the piezoelectric layers, whereas the low strength of the single-crystal materials is due to their unique crystal structure, which allows for rapid propagation of cracks initiating at flaw sites. The experimental bending strength results reported, which are linear estimates without nonlinear ferroelastic considerations, are intended for use in the design of multifunctional piezoelectric systems in which the active device is subjected to bending loads.

  16. Bending strength of delaminated aerospace composites.

    PubMed

    Kinawy, Moustafa; Butler, Richard; Hunt, Giles W

    2012-04-28

    Buckling-driven delamination is considered among the most critical failure modes in composite laminates. This paper examines the propagation of delaminations in a beam under pure bending. A pre-developed analytical model to predict the critical buckling moment of a thin sub-laminate is extended to account for propagation prediction, using mixed-mode fracture analysis. Fractography analysis is performed to distinguish between mode I and mode II contributions to the final failure of specimens. Comparison between experimental results and analysis shows agreement to within 5 per cent in static propagation moment for two different materials. It is concluded that static fracture is almost entirely driven by mode II effects. This result was unexpected because it arises from a buckling mode that opens the delamination. For this reason, and because of the excellent repeatability of the experiments, the method of testing may be a promising means of establishing the critical value of mode II fracture toughness, G(IIC), of the material. Fatigue testing on similar samples showed that buckled delamination resulted in a fatigue threshold that was over 80 per cent lower than the static propagation moment. Such an outcome highlights the significance of predicting snap-buckling moment and subsequent propagation for design purposes.

  17. The R.M.C. Design-Build-Test Projects

    ERIC Educational Resources Information Center

    Ellis, J. S.

    1971-01-01

    Four projects were assigned to final year civil engineering undergraduates in a course on structural steel design. The projects involved the design, construction, and testing of two columns and two trusses. (TS)

  18. The R.M.C. Design-Build-Test Projects

    ERIC Educational Resources Information Center

    Ellis, J. S.

    1971-01-01

    Four projects were assigned to final year civil engineering undergraduates in a course on structural steel design. The projects involved the design, construction, and testing of two columns and two trusses. (TS)

  19. Speculations on the Future of Test Design.

    DTIC Science & Technology

    1984-04-01

    test taker. It is tempting to say that adaptive testing became possible as a result of coupling computers and IRT. The fact is that Binet was doing... Alfred F. Smode, Director I Major Frank Yohannan, USME Department N-7 Headquarters, Marine Corps Naval Training Equipment Center (Code MPI-20) Orlando...20301 1 Mr. Raimond E. Christal I Ma;or jack Thorpe - . AFNRL/MOE DARPA Brooks AFB, TX 78-135 4;C Wi’sor Blvd. ,." 4 Arlington, VA 22209 I Dr. Alfred F

  20. The effect of contact stresses in four-point bend testing of graphite/epoxy and graphite/PMR-15 composite beams

    NASA Technical Reports Server (NTRS)

    Binienda, Wieslaw K.; Roberts, Gary D.; Papadopoulos, Demetrios S.

    1992-01-01

    The results of in-plane four-point bend experiments on unidirectionally reinforced composite beams are presented for graphite/epoxy (T300/934) and graphite/polyimide (G30-500/PMR-15) composites. The maximum load and the location of cracks formed during failure were measured for testpieces with fibers oriented at various angles to the beam axis. Since most of the beams failed near one or more of the load points, the strength of the beams was evaluated in terms of a proposed model, for the local stress distribution. In this model, an exact solution to the problem of a localized contact force acting on a unidirectionally reinforced half plane is used to describe the local stress field. The stress singularity at the load points is treated in a manner similar to the stress singularity at a crack tip in fracture mechanisms problems. Using this approach, the effect of fiber angle and elastic material properties on the strength of the beam is described in terms of a load intensity factor. For fiber angles less than 45 deg from the beam axis, a single crack is initiated near one of the load points at a critical value of the load intensity factor. The critical load intensity factor decreases with the increasing fiber angle. For larger fiber angles, multiple cracks occur at locations both near and away from the load points, and the load intensity factor at failure increases sharply with increasing fiber angle.

  1. Effect of contact stresses in four-point bend testing of graphite/epoxy and graphite/PMR-15 composite beams

    NASA Technical Reports Server (NTRS)

    Binienda, W. K.; Roberts, G. D.; Papadopoulos, D. S.

    1992-01-01

    The results of in-plane four-point bend experiments on unidirectionally reinforced composite beams are presented for graphite/epoxy (T300/934) and graphite/polyimide (G30-500/PMR-15) composites. The maximum load and the location of cracks formed during failure were measured for testpieces with fibers oriented at various angles to the beam axis. Since most of the beams failed near one or more of the load points, the strength of the beams was evaluated in terms of a proposed model for the local stress distribution. In this model, an exact solution to the problem of a localized contact force acting on a unidirectionally reinforced half plane is used to describe the local stress field. The stress singularity at the load points is treated in a manner similar to the stress singularity at a crack tip in fracture mechanisms problems. Using this approach, the effect of fiber angle and elastic material properties on the strength of the beam is described in terms of a load intensity factor. For fiber angles less than 45 deg from the beam axis, a single crack is initiated near one of the load points at a critical value of the load intensity factor. The critical load intensity factor decreases with increasing fiber angle. For larger fiber angles, multiple cracks occur at locations both near and away from the load points, and the load intensity factor at failure increases sharply with increasing fiber angle.

  2. Effect of contact stresses in four-point bend testing of graphite/epoxy and graphite/PMR-15 composite beams

    NASA Technical Reports Server (NTRS)

    Binienda, W. K.; Roberts, G. D.; Papadopoulos, D. S.

    1992-01-01

    The results of in-plane four-point bend experiments on unidirectionally reinforced composite beams are presented for graphite/epoxy (T300/934) and graphite/polyimide (G30-500/PMR-15) composites. The maximum load and the location of cracks formed during failure were measured for testpieces with fibers oriented at various angles to the beam axis. Since most of the beams failed near one or more of the load points, the strength of the beams was evaluated in terms of a proposed model for the local stress distribution. In this model, an exact solution to the problem of a localized contact force acting on a unidirectionally reinforced half plane is used to describe the local stress field. The stress singularity at the load points is treated in a manner similar to the stress singularity at a crack tip in fracture mechanisms problems. Using this approach, the effect of fiber angle and elastic material properties on the strength of the beam is described in terms of a load intensity factor. For fiber angles less than 45 deg from the beam axis, a single crack is initiated near one of the load points at a critical value of the load intensity factor. The critical load intensity factor decreases with increasing fiber angle. For larger fiber angles, multiple cracks occur at locations both near and away from the load points, and the load intensity factor at failure increases sharply with increasing fiber angle.

  3. Design and Laboratory Testing of a Prototype Linear Temperature Sensor

    DTIC Science & Technology

    1982-07-01

    Report DT-8203-01 Dynamics Technology, Inc. ’-4 DESIGN AND LABORATORY TESTING OF A PROTOTYPE LINEAR TEMPERATURE SENSOR C. Michael Dube and Christian...PERIOD COVERED DESIGN AND LABORATORY TESTING OF A PROTOTYPE FINAL REPORT LINEAR TEMPERATURE SENSOR 1 January 82 - 30 June 1982 7. AUTOMIGHOR. EPRTNUBE...discusses the basic theory, design, and laboratory testing of a A p.ototype linear temperature sensor (or "line sensor "), which is an instru- m1ent for

  4. Design, fabrication, testing, and delivery of improved beam steering devices

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The development, manufacture, and testing of an optical steerer intended for use in spaceborne optical radar systems are described. Included are design principles and design modifications made to harden the device against launch and space environments, the quality program and procedures developed to insure consistent product quality throughout the manufacturing phase, and engineering qualification model testing and evaluation. The delivered hardware design is considered conditionally qualified pending action on further recommended design modifications.

  5. Design development tests for composite crashworthy helicopter fuselage

    SciTech Connect

    Sen, J.K.; Dremann, C.C.

    1985-10-01

    Design development tests were conducted to investigate the crashworthy characteristics of composite helicopter fuselage subcomponents, and to design helicopter center beam/bulkhead specimens lighter than structural elements of honeycomb sandwich construction. Skinstringer designs of center beams - made of carbon, and hybrids of carbon and Kevlar - were fabricated and tested in axial compression. Crashworthy design parameters of specific energy, operating load and stroke efficiency were investigated. 8 references, 15 figures, 2 tables.

  6. Design Guidelines and Optimization Procedures for Test Subsystem Design.

    DTIC Science & Technology

    1980-04-01

    WALZ. S GREEN F30602-78 C 0167 UNCLASSIFIED R C-TR-8I-l11 L moon EE nEEooEE EEEEohhEEEshEI Ehhhhhmmmhls )C ~n 00 -*lrgl WaT j2w Ma w 4b1 Air Fore...61 3-3 Avionic-GRD Electronics R &NM Analysis During the System Design Process ......................................... 63 xv V-V...SYSTEMS, U. S. NAVAL ELECTRONICS LABORA- TORY CENTER 0179-064W Fig. 1-2 Primary Reference Documents r . :W ments are simply lowered and the BIT system

  7. FASTER test reactor preconceptual design report summary

    SciTech Connect

    Grandy, C.; Belch, H.; Brunett, A.; Heidet, F.; Hill, R.; Hoffman, E.; Jin, E.; Mohamed, W.; Moisseytsev, A.; Passerini, S.; Sienicki, J.; Sumner, T.; Vilim, R.; Hayes, Steven

    2016-02-29

    The FASTER reactor plant is a sodium-cooled fast spectrum test reactor that provides high levels of fast and thermal neutron flux for scientific research and development. The 120MWe FASTER reactor plant has a superheated steam power conversion system which provides electrical power to a local grid allowing for recovery of operating costs for the reactor plant.

  8. Design and Evaluation of Cascade Test Facility.

    DTIC Science & Technology

    1982-06-01

    New York: McGraw-Hill Book Company, 1979. 6. Erwin, John R., and James C. Emery. NACA TR 1016: Effect of Tunnel Configuration and Testing Technique on... Dgt .,opid 1 4 FEB 1983 S Force laut* 01 clbtebo legy (ATC) 19. KEY WORDS (Continue on ceverse side it necessary and identify by block number) Cascade

  9. Designing the Board's New Literature Achievement Test.

    ERIC Educational Resources Information Center

    Purves, Alan C.

    1968-01-01

    This article describes the problems that the College Entrance Examination Board's Committee of Review for the Examinations in English encountered in creating a fair, objective, hour-long literature achievement test which would meet four objectives--to measure the breadth of a student's reading, his understanding of that reading, his response to…

  10. Design, analysis and test verification of advanced encapsulation systems

    NASA Technical Reports Server (NTRS)

    Garcia, A., III

    1982-01-01

    An analytical methodology for advanced encapsulation designs was developed. From these methods design sensitivities are established for the development of photovoltaic module criteria and the definition of needed research tasks. Analytical models were developed to perform optical, thermal, electrical and analyses on candidate encapsulation systems. From these analyses several candidate systems were selected for qualification testing. Additionally, test specimens of various types are constructed and tested to determine the validity of the analysis methodology developed. Identified deficiencies and/or discrepancies between analytical models and relevant test data are corrected. Prediction capability of analytical models is improved. Encapsulation engineering generalities, principles, and design aids for photovoltaic module designers is generated.

  11. Space power distribution system technology. Volume 3: Test facility design

    NASA Technical Reports Server (NTRS)

    Decker, D. K.; Cannady, M. D.; Cassinelli, J. E.; Farber, B. F.; Lurie, C.; Fleck, G. W.; Lepisto, J. W.; Messner, A.; Ritterman, P. F.

    1983-01-01

    The AMPS test facility is a major tool in the attainment of more economical space power. The ultimate goals of the test facility, its primary functional requirements and conceptual design, and the major equipment it contains are discussed.

  12. Designing Good Experiments to Test Bad Hypotheses

    DTIC Science & Technology

    1989-08-15

    and detailed analysis of moment to moment behavior of people -- typically ordinary college students -- operating in this context (e.g., Mynatt ...work and the work of others (e.g., Mynatt et al. 1977), were not testing multiple hypotheses is revealing. In this study, subjects were given hypotheses...McGraw-Hill. Mynatt , C. R., Doherty, M. E., & Tweney, R.D. (1977). Confirmation bias in a simulated research environment: an experimental study of

  13. Generating Circuit Tests by Exploiting Designed Behavior

    DTIC Science & Technology

    1988-12-01

    determine whether the circuit is in test-mode and control /AR shifting. We modified the circuit model accordingly. Figure 6.16 shows the consequences for...productive. Yehudah Freundlich opened my mind to the history and philosophy of science. He knows lots of pretty good jokes too. Glenn Kramer, Narinder...39 2.2 Modeling Circuits and Faults ...... ...................... 44 2.2.1 Circuit Models

  14. Engineering and Design: Standard Penetration Test

    DTIC Science & Technology

    2007-11-02

    Penetration TestDe Contract Number Grant Number Program Element Number Author(s) Project Number Task Number Work Unit Number Performing Organization Name...jsfi I I US* of drlXXi~ mucl -r*ueusiog In I Decrm8e8 hcrea8ea Zither Increases Increases Increeses Decrea8es lncreeaes Increases Increeaes Zither &creases DecrU8e* nem8*s hcruses Xnt-ses tieee Utber k~ee Enclosure 2

  15. Panel Design Variations in the Multistage Test Using the Mixed-Format Tests

    ERIC Educational Resources Information Center

    Kim, Jiseon; Chung, Hyewon; Dodd, Barbara G.; Park, Ryoungsun

    2012-01-01

    This study compared various panel designs of the multistage test (MST) using mixed-format tests in the context of classification testing. Simulations varied the design of the first-stage module. The first stage was constructed according to three levels of test information functions (TIFs) with three different TIF centers. Additional computerized…

  16. Test fixture design for boron-aluminum and beryllium test panels

    NASA Technical Reports Server (NTRS)

    Breaux, C. G.

    1973-01-01

    A detailed description of the test fixture design and the backup analysis of the fixture assembly and its components are presented. The test fixture is required for the separate testing of two boron-aluminum and two beryllium compression panels. This report is presented in conjunction with a complete set of design drawings on the test fixture system.

  17. Students' Initial Knowledge State and Test Design: Towards a Valid and Reliable Test Instrument

    ERIC Educational Resources Information Center

    CoPo, Antonio Roland I.

    2015-01-01

    Designing a good test instrument involves specifications, test construction, validation, try-out, analysis and revision. The initial knowledge state of forty (40) tertiary students enrolled in Business Statistics course was determined and the same test instrument undergoes validation. The designed test instrument did not only reveal the baseline…

  18. Panel Design Variations in the Multistage Test Using the Mixed-Format Tests

    ERIC Educational Resources Information Center

    Kim, Jiseon; Chung, Hyewon; Dodd, Barbara G.; Park, Ryoungsun

    2012-01-01

    This study compared various panel designs of the multistage test (MST) using mixed-format tests in the context of classification testing. Simulations varied the design of the first-stage module. The first stage was constructed according to three levels of test information functions (TIFs) with three different TIF centers. Additional computerized…

  19. Inhibited Shaped Charge Launcher Testing of Spacecraft Shield Designs

    NASA Technical Reports Server (NTRS)

    Grosch, Donald J.

    1996-01-01

    This report describes a test program in which several orbital debris shield designs were impact tested using the inhibited shaped charge launcher facility at Southwest Research Institute. This facility enables researchers to study the impact of one-gram aluminum projectiles on various shielding designs at velocities above 11 km/s. A total of twenty tests were conducted on targets provided by NASA-MSFC. This report discusses in detail the shield design, the projectile parameters and the test configuration used for each test. A brief discussion of the target damage is provided, as the detailed analysis of the target response will be done by NASA-MSFC.

  20. Inhibited Shaped Charge Launcher Testing of Spacecraft Shield Designs

    NASA Technical Reports Server (NTRS)

    Grosch, Donald J.

    1996-01-01

    This report describes a test program in which several orbital debris shield designs were impact tested using the inhibited shaped charge launcher facility at Southwest Research Institute. This facility enables researchers to study the impact of one-gram aluminum projectiles on various shielding designs at velocities above 11 km/s. A total of twenty tests were conducted on targets provided by NASA-MSFC. This report discusses in detail the shield design, the projectile parameters and the test configuration used for each test. A brief discussion of the target damage is provided, as the detailed analysis of the target response will be done by NASA-MSFC.

  1. Z-2 Threaded Insert Design and Testing

    NASA Technical Reports Server (NTRS)

    Ross, Amy; Rhodes, Richard; Jones, Robert J.; Graziosi, David; Ferl, Jinny; Sweeny, Mitch; Scarborough, Stephen

    2016-01-01

    NASA's Z-2 prototype space suit contains several components fabricated from an advanced hybrid composite laminate consisting of IM10 carbon fiber and fiber glass. One requirement was to have removable, replaceable helicoil inserts to which other suit components would be fastened. An approach utilizing bonded in inserts with helicoils inside of them was implemented. During initial assembly, cracking sounds were heard followed by the lifting of one of the blind inserts out of its hole when the screws were torqued. A failure investigation was initiated to understand the mechanism of the failure. Ultimately, it was determined that the pre-tension caused by torqueing the fasteners is a much larger force than induced from the pressure loads of the suit which was not considered in the insert design. Bolt tension is determined by dividing the torque on the screw by a k value multiplied by the thread diameter of the bolt. The k value is a factor that accounts for friction in the system. A common value used for k for a non-lubricated screw is 0.2. The k value can go down by as much as 0.1 if the screw is lubricated which means for the same torque, a much larger tension could be placed on the bolt and insert. This paper summarizes the failure investigation that was performed to identify the root cause of the suit failure and details how the insert design was modified to resist a higher pull out tension.

  2. Design and Testing of Prototypic Elements Containing Monolithic Fuel

    SciTech Connect

    N.E. Woolstenhulme; M.K. Meyer; D.M. Wachs

    2011-10-01

    The US fuel development team has performed numerous irradiation tests on small to medium sized specimens containing low enriched uranium fuel designs. The team is now focused on qualification and demonstration of the uranium-molybdenum Base Monolithic Design and has entered the next generation of testing with the design and irradiation of prototypic elements which contain this fuel. The designs of fuel elements containing monolithic fuel, such as AFIP-7 (which is currently under irradiation) and RERTR-FE (which is currently under fabrication), are appropriate progressions relative to the technology life cycle. The culmination of this testing program will occur with the design, fabrication, and irradiation of demonstration products to include the base fuel demonstration and design demonstration experiments. Future plans show that design, fabrication, and testing activities will apply the rigor needed for a demonstration campaign.

  3. A Testlet Assembly Design for Adaptive Multistage Tests

    ERIC Educational Resources Information Center

    Luecht, Richard; Brumfield, Terry; Breithaupt, Krista

    2006-01-01

    This article describes multistage tests and some practical test development considerations related to the design and implementation of a multistage test, using the Uniform CPA (certified public accountant) Examination as a case study. The article further discusses the use of automated test assembly procedures in an operational context to produce…

  4. A Testlet Assembly Design for Adaptive Multistage Tests

    ERIC Educational Resources Information Center

    Luecht, Richard; Brumfield, Terry; Breithaupt, Krista

    2006-01-01

    This article describes multistage tests and some practical test development considerations related to the design and implementation of a multistage test, using the Uniform CPA (certified public accountant) Examination as a case study. The article further discusses the use of automated test assembly procedures in an operational context to produce…

  5. Design and testing of an electromagnetic coupling

    NASA Technical Reports Server (NTRS)

    Anderson, William J.

    1986-01-01

    Hostile environments such as the hard vacuum of space, and exposure to water or caustic fluids have fostered the development of devices which allow mechanical rotary feed throughs with positive sealing without the use of conventional dynamic seals. One such device is an electromagnetic coupling which transfers motion across a hermetic seal by means of a rotating magnetic field. Static pull-out torque and dynamic heat build-up and pull-out torque tests of a synchronous reluctance homopolar coupling are reported herein. Coupling efficiencies are estimated for a range of speeds and torques.

  6. Spatial variation in mandibular bone elastic modulus and its effect on structural bending stiffness: A test case using the Taï Forest monkeys.

    PubMed

    Le, Kim N; Marsik, Matthew; Daegling, David J; Duque, Ana; McGraw, William Scott

    2017-03-01

    We investigated how heterogeneity in material stiffness affects structural stiffness in the cercopithecid mandibular cortical bone. We assessed (1) whether this effect changes the interpretation of interspecific structural stiffness variation across four primate species, (2) whether the heterogeneity is random, and (3) whether heterogeneity mitigates bending stress in the jaw associated with food processing. The sample consisted of Taï Forest, Cote d'Ivoire, monkeys: Cercocebus atys, Piliocolobus badius, Colobus polykomos, and Cercopithecus diana. Vickers indentation hardness samples estimated elastic moduli throughout the cortical bone area of each coronal section of postcanine corpus. For each section, we calculated maximum area moment of inertia, Imax (structural mechanical property), under three models of material heterogeneity, as well as spatial autocorrelation statistics (Moran's I, IMORAN ). When the model considered material stiffness variation and spatial patterning, Imax decreased and individual ranks based on structural stiffness changed. Rank changes were not significant across models. All specimens showed positive (nonrandom) spatial autocorrelation. Differences in IMORAN were not significant among species, and there were no discernable patterns of autocorrelation within species. Across species, significant local IMORAN was often attributed to proximity of low moduli in the alveolar process and high moduli in the basal process. While our sample did not demonstrate species differences in the degree of spatial autocorrelation of elastic moduli, there may be mechanical effects of heterogeneity (relative strength and rigidity) that do distinguish at the species or subfamilial level (i.e., colobines vs. cercopithecines). The potential connections of heterogeneity to diet and/or taxonomy remain to be discovered. © 2016 Wiley Periodicals, Inc.

  7. Design and testing of small composite specimens

    NASA Technical Reports Server (NTRS)

    Sharma, A. V.

    1981-01-01

    The effect of specimen size on the buckling strains of laminates subjected to low velocity projectile impact was investigated. The fiber composite selected was T300/5208 graphite/epoxy system. The quasi-isotropic laminates tested had 16 and 32 plies. The results were compared with those of a 48-ply laminate. Specimens of three different lengths with length to width aspect ratios of 1, 1.5, and 2 were also studied. The results show that (1) the specimen length does not have any significant influence on the buckling strains at failure caused by the projectile impact, and (2) the influence of specimen thickness on the strains at failure would decrease as the velocity of the impacting projectile increases.

  8. Development and testing of new upper-limb prosthetic devices: research designs for usability testing.

    PubMed

    Resnik, Linda

    2011-01-01

    The purposes of this article are to describe usability testing and introduce designs and methods of usability testing research as it relates to upper-limb prosthetics. This article defines usability, describes usability research, discusses research approaches to and designs for usability testing, and highlights a variety of methodological considerations, including sampling, sample size requirements, and usability metrics. Usability testing is compared with other types of study designs used in prosthetic research.

  9. Using partial safety factors in wind turbine design and testing

    SciTech Connect

    Musial, W D; Butterfield, C

    1997-09-01

    This paper describes the relationship between wind turbine design and testing in terms of the certification process. An overview of the current status of international certification is given along with a description of limit-state design basics. Wind turbine rotor blades are used to illustrate the principles discussed. These concepts are related to both International Electrotechnical Commission and Germanischer Lloyd design standards, and are covered using schematic representations of statistical load and material strength distributions. Wherever possible, interpretations of the partial safety factors are given with descriptions of their intended meaning. Under some circumstances, the authors` interpretations may be subjective. Next, the test-load factors are described in concept and then related to the design factors. Using technical arguments, it is shown that some of the design factors for both load and materials must be used in the test loading, but some should not be used. In addition, some test factors not used in the design may be necessary for an accurate test of the design. The results show that if the design assumptions do not clearly state the effects and uncertainties that are covered by the design`s partial safety factors, outside parties such as test labs or certification agencies could impose their own meaning on these factors.

  10. Using partial safety factors in wind turbine design and testing

    SciTech Connect

    Musial, W.D.

    1997-12-31

    This paper describes the relationship between wind turbine design and testing in terms of the certification process. An overview of the current status of international certification is given along with a description of limit-state design basics. Wind turbine rotor blades are used to illustrate the principles discussed. These concepts are related to both International Electrotechnical Commission and Germanischer Lloyd design standards, and are covered using schematic representations of statistical load and material strength distributions. Wherever possible, interpretations of the partial safety factors are given with descriptions of their intended meaning. Under some circumstances, the authors` interpretations may be subjective. Next, the test-load factors are described in concept and then related to the design factors. Using technical arguments, it is shown that some of the design factors for both load and materials must be used in the test loading, but some should not be used. In addition, some test factors not used in the design may be necessary for an accurate test of the design. The results show that if the design assumptions do not clearly state the effects and uncertainties that are covered by the design`s partial safety factors, outside parties such as test labs or certification agencies could impose their own meaning on these factors.

  11. Optimal Design of Item Banks for Computerized Adaptive Tests.

    ERIC Educational Resources Information Center

    Stocking, Martha L.; Swanson, Len

    1998-01-01

    Applied optimal design methods to the item-bank design of adaptive testing for continuous testing situations using a version of the weighted-deviations model (M. Stocking and L. Swanson, 1993) in a simulation. Independent and overlapping item banks used items more efficiently than did a large item bank. (SLD)

  12. Design and testing of a superfluid liquid helium cooling loop

    SciTech Connect

    Gavin, L.M.; Green, M.A.; Levin, S.M.; Smoot, G.F.; Witebsky, C.

    1989-07-01

    This paper describes the design and preliminary testing of a cryogenic cooling loop that uses a thermomechanical pump to circulate superfluid liquid helium. The cooling loop test apparatus is designed to prove forced liquid helium flow concepts that will be used on the Astromag superconducting magnet facility. 3 refs., 2 figs.

  13. Optimal Design of Item Banks for Computerized Adaptive Tests.

    ERIC Educational Resources Information Center

    Stocking, Martha L.; Swanson, Len

    1998-01-01

    Applied optimal design methods to the item-bank design of adaptive testing for continuous testing situations using a version of the weighted-deviations model (M. Stocking and L. Swanson, 1993) in a simulation. Independent and overlapping item banks used items more efficiently than did a large item bank. (SLD)

  14. Design, analysis and test verification of advanced encapsulation systems

    NASA Technical Reports Server (NTRS)

    Garcia, A., III

    1983-01-01

    The analytical methodology for advanced encapsulation designs for the development of photovoltaic modules is presented. Analytical models are developed to test optical, thermal, electrical and structural properties of the various encapsulation systems. Model data is compared to relevant test data to improve model accuracy and develop general principles for the design of photovoltaic modules.

  15. Bending properties of nickel electrodes for nickel-hydrogen batteries

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley

    1995-01-01

    Recent changes in manufacturing have resulted in nickel-hydrogen batteries which fail prematurely by electrical shorting. This is believed to be a result of a blistering problem in the nickel electrodes. This study investigates the bending properties of nickel electrodes in an attempt to correlate the bending properties with the propensity of the electrode to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. Effects of specimen curvature and position within the electrode on the bending strength were studied and within-electrode and batch-to-batch variation were addressed. Two color imaging techniques were employed which allowed differentiation of phases within the electrodes. These techniques aided in distinguishing the relative amounts of nickel hydroxide surface loading on each electrode, relating surface loading to bend strength. Bend strength was found to increase with the amount of surface loading.

  16. Bending properties of nickel electrodes for nickel-hydrogen batteries

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley

    1995-01-01

    Recent changes in manufacturing have resulted in nickel-hydrogen batteries which fail prematurely by electrical shorting. This is believed to be a result of a blistering problem in the nickel electrodes. This study investigates the bending properties of nickel electrodes in an attempt to correlate the bending properties with the propensity of the electrode to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. Effects of specimen curvature and position within the electrode on the bending strength were studied and within-electrode and batch-to-batch variation were addressed. Two color imaging techniques were employed which allowed differentiation of phases within the electrodes. These techniques aided in distinguishing the relative amounts of nickel hydroxide surface loading on each electrode, relating surface loading to bend strength. Bend strength was found to increase with the amount of surface loading.

  17. Bending Properties of Nickel Electrodes for Nickel-Hydrogen Batteries

    NASA Technical Reports Server (NTRS)

    Lerch, Brad A.; Wilson, Richard M.; Keller, Dennis; Corner, Ralph

    1995-01-01

    Recent changes in manufacturing have resulted in nickel-hydrogen batteries that fail prematurely by electrical shorting, This failure is believed to be a result of a blistering problem in the nickel electrodes. In this study the bending properties of nickel electrodes are investigated in an attempt to correlate the bending properties of the electrode with its propensity to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. The effects of specimen curvature and position within the electrode on the bending strength were studied, and within-electrode and batch-to-batch variations were addressed. Two color-imaging techniques were employed to differentiate between the phases within the electrodes. These techniques aided in distinguishing the relative amounts of nickel hyroxide surface loading on each electrode, thereby relating surface loading to bend strength. Bend strength was found to increase with the amount of surface loading.

  18. Overall Thermal Performance of Flexible Piping Under Simulated Bending Conditions

    NASA Technical Reports Server (NTRS)

    Fesmire, James E.; Augustynowicz, S. D.; Demko, J. A.; Thompson, Karen (Technical Monitor)

    2001-01-01

    Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k(sub oafi)) is described for use in design and analysis of cryogenic piping systems.

  19. Overall thermal performance of flexible piping under simulated bending conditions

    NASA Astrophysics Data System (ADS)

    Fesmire, J. E.; Augustynowicz, S. D.; Demko, J. A.

    2002-05-01

    Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (koafi) is described for use in design and analysis of cryogenic piping systems.

  20. The Design, Fabrication, and Testing of Composite Heat Exchange Coupons

    NASA Technical Reports Server (NTRS)

    Quade, Derek J.; Meador, Michael A.; Shin, Euy-Sik; Johnston, James C.; Kuczmarski, Maria A.

    2011-01-01

    Several heat exchanger (HX) test panels were designed, fabricated and tested at the NASA Glenn Research Center to explore the fabrication and performance of several designs for composite heat exchangers. The development of these light weight, high efficiency air-liquid test panels was attempted using polymer composites and carbon foam materials. The fundamental goal of this effort was to demonstrate the feasibility of the composite HX for various space exploration and thermal management applications including Orion CEV and Altair. The specific objectives of this work were to select optimum materials, designs, and to optimize fabrication procedures. After fabrication, the individual design concept prototypes were tested to determine their thermal performance and to guide the future development of full-size engineering development units (EDU). The overall test results suggested that the panel bonded with pre-cured composite laminates to KFOAM Grade L1 scored above the other designs in terms of ease of manufacture and performance.

  1. ZERODUR: bending strength data for etched surfaces

    NASA Astrophysics Data System (ADS)

    Hartmann, Peter; Leys, Antoine; Carré, Antoine; Kerz, Franca; Westerhoff, Thomas

    2014-07-01

    In a continuous effort since 2007 a considerable amount of new data and information has been gathered on the bending strength of the extremely low thermal expansion glass ceramic ZERODUR®. By fitting a three parameter Weibull distribution to the data it could be shown that for homogenously ground surfaces minimum breakage stresses exist lying much higher than the previously applied design limits. In order to achieve even higher allowable stress values diamond grain ground surfaces have been acid etched, a procedure widely accepted as strength increasing measure. If surfaces are etched taking off layers with thickness which are comparable to the maximum micro crack depth of the preceding grinding process they also show statistical distributions compatible with a three parameter Weibull distribution. SCHOTT has performed additional measurement series with etch solutions with variable composition testing the applicability of this distribution and the possibility to achieve further increase of the minimum breakage stress. For long term loading applications strength change with time and environmental media are important. The parameter needed for prediction calculations which is combining these influences is the stress corrosion constant. Results from the past differ significantly from each other. On the basis of new investigations better information will be provided for choosing the best value for the given application conditions.

  2. Space station prototype Sabatier reactor design verification testing

    NASA Technical Reports Server (NTRS)

    Cusick, R. J.

    1974-01-01

    A six-man, flight prototype carbon dioxide reduction subsystem for the SSP ETC/LSS (Space Station Prototype Environmental/Thermal Control and Life Support System) was developed and fabricated for the NASA-Johnson Space Center between February 1971 and October 1973. Component design verification testing was conducted on the Sabatier reactor covering design and off-design conditions as part of this development program. The reactor was designed to convert a minimum of 98 per cent hydrogen to water and methane for both six-man and two-man reactant flow conditions. Important design features of the reactor and test conditions are described. Reactor test results are presented that show design goals were achieved and off-design performance was stable.

  3. A Dark Bend

    NASA Image and Video Library

    2016-09-05

    Saturn's rings appear to bend as they pass behind the planet's darkened limb due to refraction by Saturn's upper atmosphere. The effect is the same as that seen in an earlier Cassini view (see PIA20491), except this view looks toward the unlit face of the rings, while the earlier image viewed the rings' sunlit side. The difference in illumination brings out some noticeable differences. The A ring is much darker here, on the rings' unlit face, since its larger particles primarily reflect light back toward the sun (and away from Cassini's cameras in this view). The narrow F ring (at bottom), which was faint in the earlier image, appears brighter than all of the other rings here, thanks to the microscopic dust that is prevalent within that ring. Small dust tends to scatter light forward (meaning close to its original direction of travel), making it appear bright when backlit. (A similar effect has plagued many a driver with a dusty windshield when driving toward the sun.) This view looks toward the unilluminated side of the rings from about 19 degrees below the ring plane. The image was taken in red light with the Cassini spacecraft narrow-angle camera on July 24, 2016. The view was acquired at a distance of approximately 527,000 miles (848,000 kilometers) from Saturn and at a sun-Saturn-spacecraft, or phase, angle of 169 degrees. Image scale is 3 miles (5 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20497

  4. Design requirements for the supercritical water oxidation test bed

    SciTech Connect

    Svoboda, J.M.; Valentich, D.J.

    1994-05-01

    This report describes the design requirements for the supercritical water oxidation (SCWO) test bed that will be located at the Idaho National Engineering Laboratory (INEL). The test bed will process a maximum of 50 gph of waste plus the required volume of cooling water. The test bed will evaluate the performance of a number of SCWO reactor designs. The goal of the project is to select a reactor that can be scaled up for use in a full-size waste treatment facility to process US Department of Energy mixed wastes. EG&G Idaho, Inc. will design and construct the SCWO test bed at the Water Reactor Research Test Facility (WRRTF), located in the northern region of the INEL. Private industry partners will develop and provide SCWO reactors to interface with the test bed. A number of reactor designs will be tested, including a transpiring wall, tube, and vessel-type reactor. The initial SCWO reactor evaluated will be a transpiring wall design. This design requirements report identifies parameters needed to proceed with preliminary and final design work for the SCWO test bed. A flow sheet and Process and Instrumentation Diagrams define the overall process and conditions of service and delineate equipment, piping, and instrumentation sizes and configuration Codes and standards that govern the safe engineering and design of systems and guidance that locates and interfaces test bed hardware are provided. Detailed technical requirements are addressed for design of piping, valves, instrumentation and control, vessels, tanks, pumps, electrical systems, and structural steel. The approach for conducting the preliminary and final designs and environmental and quality issues influencing the design are provided.

  5. Recent developments in bend-insensitive and ultra-bend-insensitive fibers

    NASA Astrophysics Data System (ADS)

    Boivin, David; de Montmorillon, Louis-Anne; Provost, Lionel; Montaigne, Nelly; Gooijer, Frans; Aldea, Eugen; Jensma, Jaap; Sillard, Pierre

    2010-02-01

    Designed to overcome the limitations in case of extreme bending conditions, Bend- and Ultra-Bend-Insensitive Fibers (BIFs and UBIFs) appear as ideal solutions for use in FTTH networks and in components, pigtails or patch-cords for ever demanding applications such as military or sensing. Recently, however, questions have been raised concerning the Multi-Path-Interference (MPI) levels in these fibers. Indeed, they are potentially subject to interferences between the fundamental mode and the higher-order mode that is also bend resistant. This MPI is generated because of discrete discontinuities such as staples, bends and splices/connections that occur on distance scales that become comparable to the laser coherent length. In this paper, we will demonstrate the high MPI tolerance of all-solid single-trench-assisted BIFs and UBIFs. We will present the first comprehensive study combining theoretical and experimental points of view to quantify the impact of fusion splices on coherent MPI. To be complete, results for mechanical splices will also be reported. Finally, we will show how the single-trench- assisted concept combined with the versatile PCVD process allows to tightly control the distributions of fibers characteristics. Such controls are needed to massively produce BIFs and to meet the more stringent specifications of the UBIFs.

  6. A soft stretchable bending sensor and data glove applications.

    PubMed

    Shen, Zhong; Yi, Juan; Li, Xiaodong; Lo, Mark Hin Pei; Chen, Michael Z Q; Hu, Yong; Wang, Zheng

    2016-01-01

    Soft sensors are required to accommodate the flexible and deformable natures of the human body in wearable device applications. They are also suitable for integration with soft robotic devices to monitor the performance status and provide references for feedback control. However, the choices for bending sensors are still highly limited. In this paper, a soft bending sensor is presented. By careful design with a blend of sensitive and insensitive regions, the sensor could be stretchable while being insensitive to stretching. An analytical study was presented on how to design the sensor with the named bending/stretching feature. This feature enables the sensor to be implemented in measuring human motions where a large amount of skin stretch is involved. Two sensor gloves were designed and fabricated based on the proposed soft bending sensor, aiming for different application scenarios. Both the sensor and the gloves were evaluated using a dedicated evaluation platform with experimental results compared against each other.

  7. Design, fabrication, testing and delivery of a solar collector

    NASA Technical Reports Server (NTRS)

    Sims, W. H.; Ballheim, R. W.; Bartley, S. M.; Smith, G. W.

    1976-01-01

    A two phase program encompassing the redesign and fabrication of a solar collector which is low in cost and aesthetically appealing is described. Phase one work reviewed the current collector design and developed a low-cost design based on specific design/performance/cost requirements. Throughout this phase selected collector component materials were evaluated by testing and by considering cost, installation, maintainability and durability. The resultant collector design was composed of an absorber plate, insulation, frame, cover, desiccant and sealant. In Phase two, three collector prototypes were fabricated and evaluated for both nonthermal and thermal characteristics. Tests included static load tests of covers, burst pressure tests of absorber plates, and tests for optical characteristics of selective absorber plate coatings. The three prototype collectors were shipped to Marshall Space Flight Center for use in their solar heating and cooling test facility.

  8. Testing block subdivision algorithms on block designs

    NASA Astrophysics Data System (ADS)

    Wiseman, Natalie; Patterson, Zachary

    2016-01-01

    Integrated land use-transportation models predict future transportation demand taking into account how households and firms arrange themselves partly as a function of the transportation system. Recent integrated models require parcels as inputs and produce household and employment predictions at the parcel scale. Block subdivision algorithms automatically generate parcel patterns within blocks. Evaluating block subdivision algorithms is done by way of generating parcels and comparing them to those in a parcel database. Three block subdivision algorithms are evaluated on how closely they reproduce parcels of different block types found in a parcel database from Montreal, Canada. While the authors who developed each of the algorithms have evaluated them, they have used their own metrics and block types to evaluate their own algorithms. This makes it difficult to compare their strengths and weaknesses. The contribution of this paper is in resolving this difficulty with the aim of finding a better algorithm suited to subdividing each block type. The proposed hypothesis is that given the different approaches that block subdivision algorithms take, it's likely that different algorithms are better adapted to subdividing different block types. To test this, a standardized block type classification is used that consists of mutually exclusive and comprehensive categories. A statistical method is used for finding a better algorithm and the probability it will perform well for a given block type. Results suggest the oriented bounding box algorithm performs better for warped non-uniform sites, as well as gridiron and fragmented uniform sites. It also produces more similar parcel areas and widths. The Generalized Parcel Divider 1 algorithm performs better for gridiron non-uniform sites. The Straight Skeleton algorithm performs better for loop and lollipop networks as well as fragmented non-uniform and warped uniform sites. It also produces more similar parcel shapes and patterns.

  9. Effect of bend separation distance on the mass transfer in back-to-back pipe bends arranged in a 180° configuration

    NASA Astrophysics Data System (ADS)

    Chen, X.; Le, T.; Ewing, D.; Ching, C. Y.

    2016-12-01

    The mass transfer to turbulent flow through back-to-back pipe bends arranged in a 180° configuration with different lengths of pipe between the bends was measured using a dissolving gypsum test section in water. The measurements were performed for bends with a radius of curvature of 1.5 times the pipe diameter ( D) at a Reynolds numbers of 70,000 and Schmidt number of 1280. The maximum mass transfer in the bends decreased from approximately 1.8 times the mass transfer in the upstream pipe when there was no separation distance between the bends to 1.7 times when there was a 1 D or 5 D length of pipe between the bends. The location of the maximum mass transfer was on the inner sidewall downstream of the second bend when there was no separation distance between the bends. This location changed to the inner wall at the beginning of the second bend when there was a 1 D long pipe between the bends, and to the inner sidewall at the end of the first bend when there was a 5 D long pipe between the bends.

  10. In vivo measurement of bending stiffness in fracture healing

    PubMed Central

    Hente, Reiner; Cordey, Jacques; Perren, Stephan M

    2003-01-01

    Background Measurement of the bending stiffness a healing fracture represents a valid variable in the assessment of fracture healing. However, currently available methods typically have high measurement errors, even for mild pin loosening. Furthermore, these methods cannot provide actual values of bending stiffness, which precludes comparisons among individual fractures. Thus, even today, little information is available with regards to the fracture healing pattern with respect to actual values of bending stiffness. Our goals were, therefore: to develop a measurement device that would allow accurate and sensitive measurement of bending stiffness, even in the presence of mild pin loosening; to describe the course of healing in individual fractures; and help to evaluate whether the individual pattern of bending stiffness can be predicted at an early stage of healing. Methods A new measurement device has been developed to precisely measure the bending stiffness of the healing fracture by simulating four-point-bending. The system was calibrated on aluminum models and intact tibiae. The influence of pin loosening on measurement error was evaluated. The system was tested at weekly intervals in an animal experiment to determine the actual bending stiffness of the fracture. Transverse fractures were created in the right tibia of twelve sheep, and then stabilized with an external fixator. At ten weeks, bending stiffness of the tibiae were determined in a four-point-bending test device to validate the in-vivo-measurement data. Results In-vivo bending stiffness can be measured accurately and sensitive, even in the early phase of callus healing. Up to a bending stiffness of 10 Nm/degree, measurement error was below 3.4% for one pin loose, and below 29.3% for four pins loose, respectively. Measurement of stiffness data over time revealed a significant logarithmic increase between the third and seventh weeks, whereby the logarithmic rate of change among sheep was similar, but

  11. Study of test script design methods for Web Service performance testing

    NASA Astrophysics Data System (ADS)

    Xu, Peng

    2017-09-01

    Web Service interface technology is more and more widely applied in information system. And more requirements of Web Service performance testing are demanded. Nevertheless, designing the test script for performance testing is hard to take into practice. In this paper, two kinds of test script design methods for Web Service performance testing are presented by using LoadRunner and SOAP UI tools. That is The Service Call Method and The SOAP Method.

  12. The effect of skin passing on the material behavior of metal strip in pure bending and tension

    NASA Astrophysics Data System (ADS)

    Weiss, Matthias; Ryan, Will; Rolfe, Bernard; Yang, Chunhui

    2010-06-01

    The metal strip used in roll forming has often been preprocessed by (tension or roller) leveling or by skin-pass rolling, and as a consequence, may contain residual stresses. These stresses are not well observed by the tensile test, but could have a significant effect on the bending and springback behavior. With the advent of improved process design techniques for roll forming, including advanced finite element techniques, the need for precise material property data has become important. The major deformation mode of roll forming is that of bending combined with unloading and reverse bending, and hence property data derived from bend tests could be more relevant than that from tensile testing. This work presents a numerical study on the effect of skin passing on the material behavior of stainless steel strip in pure bending and tension. A two dimensional (2-D) numerical model was developed using Abaqus Explicit to analyze the affect of skin passing on the residual stress profile across a section for various working conditions. The deformed meshes and their final stress fields were then imported as pre-defined fields into Abaqus Standard, and the post-skin passing material behavior in pure bending was determined. The results show that a residual stress profile is introduced into the steel strip during skin passing, and that its shape and stress level depend on the overall thickness reduction as well as the number of rolling passes used in the skin passing process. The material behavior in bending and the amount of springback changed significantly depending on the skin pass condition.

  13. Effect of screw insertion torque on push-out and cantilever bending properties of five different angle-stable systems.

    PubMed

    Boero Baroncelli, Alessandro; Reif, Ulrich; Bignardi, Cristina; Peirone, Bruno

    2013-04-01

    To compare the screw push-out strength and resistance to cantilever bending of 5 different angle-stable systems using 4 different insertion torque values to tighten locking screws. In vitro mechanical testing of 5 screw-plate constructs. Screw plate constructs (n = 60) were tested; 12 of each design, 3 for each torque value. To compare push-out strength, screws were loaded in axial direction on the screw tip until loosening of the locking mechanism was recorded. For cantilever bending test, screws were loaded perpendicularly to their longitudinal axis at 2 mm of distance from the under surface of the plate. Load was applied in displacement control at 1 mm/min. There was a significant difference between the 5 different angle-stable systems regarding both push-out and cantilever bending strength. There was an influence of insertion torque value on push-out strength for 2 systems and insertion torque value influenced cantilever bending behavior only in 1 locking system. Locking mechanisms using "thread in thread" principle provided a stronger screw push-out behavior. Screws materials and core diameter of the different screws were directly related to cantilever bending strength. © Copyright 2013 by The American College of Veterinary Surgeons.

  14. Reliability based design including future tests and multiagent approaches

    NASA Astrophysics Data System (ADS)

    Villanueva, Diane

    The initial stages of reliability-based design optimization involve the formulation of objective functions and constraints, and building a model to estimate the reliability of the design with quantified uncertainties. However, even experienced hands often overlook important objective functions and constraints that affect the design. In addition, uncertainty reduction measures, such as tests and redesign, are often not considered in reliability calculations during the initial stages. This research considers two areas that concern the design of engineering systems: 1) the trade-off of the effect of a test and post-test redesign on reliability and cost and 2) the search for multiple candidate designs as insurance against unforeseen faults in some designs. In this research, a methodology was developed to estimate the effect of a single future test and post-test redesign on reliability and cost. The methodology uses assumed distributions of computational and experimental errors with re-design rules to simulate alternative future test and redesign outcomes to form a probabilistic estimate of the reliability and cost for a given design. Further, it was explored how modeling a future test and redesign provides a company an opportunity to balance development costs versus performance by simultaneously designing the design and the post-test redesign rules during the initial design stage. The second area of this research considers the use of dynamic local surrogates, or surrogate-based agents, to locate multiple candidate designs. Surrogate-based global optimization algorithms often require search in multiple candidate regions of design space, expending most of the computation needed to define multiple alternate designs. Thus, focusing on solely locating the best design may be wasteful. We extended adaptive sampling surrogate techniques to locate multiple optima by building local surrogates in sub-regions of the design space to identify optima. The efficiency of this method

  15. Test methods and design allowables for fibrous composites. Volume 2

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C. (Editor)

    1989-01-01

    Topics discussed include extreme/hostile environment testing, establishing design allowables, and property/behavior specific testing. Papers are presented on environmental effects on the high strain rate properties of graphite/epoxy composite, the low-temperature performance of short-fiber reinforced thermoplastics, the abrasive wear behavior of unidirectional and woven graphite fiber/PEEK, test methods for determining design allowables for fiber reinforced composites, and statistical methods for calculating material allowables for MIL-HDBK-17. Attention is also given to a test method to measure the response of composite materials under reversed cyclic loads, a through-the-thickness strength specimen for composites, the use of torsion tubes to measure in-plane shear properties of filament-wound composites, the influlence of test fixture design on the Iosipescu shear test for fiber composite materials, and a method for monitoring in-plane shear modulus in fatigue testing of composites.

  16. Test methods and design allowables for fibrous composites. Volume 2

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C. (Editor)

    1989-01-01

    Topics discussed include extreme/hostile environment testing, establishing design allowables, and property/behavior specific testing. Papers are presented on environmental effects on the high strain rate properties of graphite/epoxy composite, the low-temperature performance of short-fiber reinforced thermoplastics, the abrasive wear behavior of unidirectional and woven graphite fiber/PEEK, test methods for determining design allowables for fiber reinforced composites, and statistical methods for calculating material allowables for MIL-HDBK-17. Attention is also given to a test method to measure the response of composite materials under reversed cyclic loads, a through-the-thickness strength specimen for composites, the use of torsion tubes to measure in-plane shear properties of filament-wound composites, the influlence of test fixture design on the Iosipescu shear test for fiber composite materials, and a method for monitoring in-plane shear modulus in fatigue testing of composites.

  17. The Design and Field Test of the ACT Portfolio System.

    ERIC Educational Resources Information Center

    Reckase, Mark D.

    The American College Testing Program (ACT) is field testing a portfolio assessment model. The field test is designed to determine whether it is possible to implement a portfolio assessment model on a national level that will result in scores that are of sufficient reliability and validity that they can be used for decisions at the student level.…

  18. Designing an Affordable Usability Test for E-Learning Modules

    ERIC Educational Resources Information Center

    O'Bryan, Corliss A.; Johnson, Donald M.; Shores-Ellis, Katrina D.; Crandall, Philip G.; Marcy, John A.; Seideman, Steve C.; Ricke, Steven C.

    2010-01-01

    This article provides background and an introduction to a user-centered design and usability test in an inexpensive format that allows content experts who are novices in e-learning development to perform testing on newly developed technical training modules prior to their release. The use of a small number of test participants, avoidance of…

  19. Optical design for the Laser Astrometric Test of Relativity

    NASA Technical Reports Server (NTRS)

    Turyshev, Slava G.; Shao, Michael; Nordtvedt, Kenneth L., Jr.

    2004-01-01

    This paper discusses the Laser Astrometric Test of Relativity (LATOR) mission. LATOR is a Michelson-Morley-type experiment designed to test the pure tensor metric nature of gravitation the fundamental postulate of Einstein's theory of general relativity. With its focus on gravity's action on light propagation it complements other tests which rely on the gravitational dynamics of bodies.

  20. Multidimensional Adaptive Testing with Optimal Design Criteria for Item Selection

    ERIC Educational Resources Information Center

    Mulder, Joris; van der Linden, Wim J.

    2009-01-01

    Several criteria from the optimal design literature are examined for use with item selection in multidimensional adaptive testing. In particular, it is examined what criteria are appropriate for adaptive testing in which all abilities are intentional, some should be considered as a nuisance, or the interest is in the testing of a composite of the…

  1. Designing an Affordable Usability Test for E-Learning Modules

    ERIC Educational Resources Information Center

    O'Bryan, Corliss A.; Johnson, Donald M.; Shores-Ellis, Katrina D.; Crandall, Philip G.; Marcy, John A.; Seideman, Steve C.; Ricke, Steven C.

    2010-01-01

    This article provides background and an introduction to a user-centered design and usability test in an inexpensive format that allows content experts who are novices in e-learning development to perform testing on newly developed technical training modules prior to their release. The use of a small number of test participants, avoidance of…

  2. Optical design for the Laser Astrometric Test of Relativity

    NASA Technical Reports Server (NTRS)

    Turyshev, Slava G.; Shao, Michael; Nordtvedt, Kenneth L., Jr.

    2004-01-01

    This paper discusses the Laser Astrometric Test of Relativity (LATOR) mission. LATOR is a Michelson-Morley-type experiment designed to test the pure tensor metric nature of gravitation the fundamental postulate of Einstein's theory of general relativity. With its focus on gravity's action on light propagation it complements other tests which rely on the gravitational dynamics of bodies.

  3. A flight test facility design for examining digital information transfer

    NASA Technical Reports Server (NTRS)

    Knox, Charles E.

    1990-01-01

    Information is given in viewgraph form on a flight test facility design for examining digital information transfer. Information is given on aircraft/ground exchange, data link research activities, data link display format, a data link flight test, and the flight test setup.

  4. Task 8 -- Design and test of critical components

    SciTech Connect

    Chance, T.F.

    1996-11-01

    This report covers tasks 8.1, 8.1.1, and 8.2. The primary objective of Task 8.1, Particulates Flow Deposition, is to characterize the particulate generated in an operating gas turbine combined cycle (GTCC) power plant whose configuration approximates that proposed for an ATS power plant. In addition, the task is to evaluate the use of full-flow filtering to reduce the steam particulate loads. Before the start of this task, GE had already negotiated an agreement with the candidate power plant, piping and a filter unit had already been installed at the power plant site, and major elements of the data acquisition system had been purchased. The objective of Task 8.1.1, Coolant Purity, is to expose typical ATS gas turbine airfoil cooling channel geometries to real steam flow to determine whether there are any unexpected deposit formations. The task is a static analog of the centrifugal deposition rig trials of Task 8.2, in which a bucket channel return bend is exposed to steam flow. Two cooling channel geometries are of primary interest in this static exposure. The primary objective of Task 8.2, Particle Centrifugal Sedimentation, is to determine the settling characteristics of particles in a cooling stream from an operating gas turbine combined cycle (GTCC) power plant when that stream is ducted through a passage experiencing the G-loads expected in a simulated bucket channel specimen representative of designs proposed for an ATS gas turbine.

  5. Prototype spent-fuel canister design, analysis, and test

    SciTech Connect

    Leisher, W.B.; Eakes, R.G.; Duffey, T.A.

    1982-03-01

    Sandia National Laboratories was asked by the US Energy Research and Development Administration (now US Department of Energy) to design the spent fuel shipping cask system for the Clinch River Breeder Reactor Plant (CRBRP). As a part of this task, a canister which holds liquid sodium and the spent fuel assembly was designed, analyzed, and tested. The canister body survived the regulatory Type-B 9.1-m (30-ft) drop test with no apparent leakage. However, the commercially available metal seal used in this design leaked after the tests. This report describes the design approach, analysis, and prototype canister testing. Recommended work for completing the design, when funding is available, is included.

  6. Hybrid Computerized Adaptive Testing: From Group Sequential Design to Fully Sequential Design

    ERIC Educational Resources Information Center

    Wang, Shiyu; Lin, Haiyan; Chang, Hua-Hua; Douglas, Jeff

    2016-01-01

    Computerized adaptive testing (CAT) and multistage testing (MST) have become two of the most popular modes in large-scale computer-based sequential testing. Though most designs of CAT and MST exhibit strength and weakness in recent large-scale implementations, there is no simple answer to the question of which design is better because different…

  7. Hybrid Computerized Adaptive Testing: From Group Sequential Design to Fully Sequential Design

    ERIC Educational Resources Information Center

    Wang, Shiyu; Lin, Haiyan; Chang, Hua-Hua; Douglas, Jeff

    2016-01-01

    Computerized adaptive testing (CAT) and multistage testing (MST) have become two of the most popular modes in large-scale computer-based sequential testing. Though most designs of CAT and MST exhibit strength and weakness in recent large-scale implementations, there is no simple answer to the question of which design is better because different…

  8. The J-2X Fuel Turbopump - Design, Development, and Test

    NASA Technical Reports Server (NTRS)

    Tellier, James G.; Hawkins, Lakiesha V.; Shinguchi, Brian H.; Marsh, Matthew W.

    2011-01-01

    Pratt and Whitney Rocketdyne (PWR), a NASA subcontractor, is executing the design, development, test, and evaluation (DDT&E) of a liquid oxygen, liquid hydrogen two hundred ninety four thousand pound thrust rocket engine initially intended for the Upper Stage (US) and Earth Departure Stage (EDS) of the Constellation Program Ares-I Crew Launch Vehicle (CLV). A key element of the design approach was to base the new J-2X engine on the heritage J-2S engine with the intent of uprating the engine and incorporating SSME and RS-68 lessons learned. The J-2S engine was a design upgrade of the flight proven J-2 configuration used to put American astronauts on the moon. The J-2S Fuel Turbopump (FTP) was the first Rocketdyne-designed liquid hydrogen centrifugal pump and provided many of the early lessons learned for the Space Shuttle Main Engine High Pressure Fuel Turbopumps. This paper will discuss the design trades and analyses performed for the current J-2X FTP to increase turbine life; increase structural margins, facilitate component fabrication; expedite turbopump assembly; and increase rotordynamic stability margins. Risk mitigation tests including inducer water tests, whirligig turbine blade tests, turbine air rig tests, and workhorse gas generator tests characterized operating environments, drove design modifications, or identified performance impact. Engineering design, fabrication, analysis, and assembly activities support FTP readiness for the first J-2X engine test scheduled for July 2011.

  9. Design of Multilayer Insulation for the Multipurpose Hydrogen Test Bed

    NASA Technical Reports Server (NTRS)

    Marlow, Weston A.

    2011-01-01

    Multilayer insulation (MLI) is a critical component for future, long term space missions. These missions will require the storage of cryogenic fuels for extended periods of time with little to no boil-off and MLI is vital due to its exceptional radiation shielding properties. Several MLI test articles were designed and fabricated which explored methods of assembling and connecting blankets, yielding results for evaluation. Insight gained, along with previous design experience, will be used in the design of the replacement blanket for the Multipurpose Hydrogen Test Bed (MHTB), which is slated for upcoming tests. Future design considerations are discussed which include mechanical testing to determine robustness of such a system, as well as cryostat testing of samples to give insight to the loss of thermal performance of sewn panels in comparison to the highly efficient, albeit laborious application of the original MHTB blanket.

  10. Design and Construction of a Hydroturbine Test Facility

    NASA Astrophysics Data System (ADS)

    Ayli, Ece; Kavurmaci, Berat; Cetinturk, Huseyin; Kaplan, Alper; Celebioglu, Kutay; Aradag, Selin; Tascioglu, Yigit; ETU Hydro Research Center Team

    2014-11-01

    Hydropower is one of the clean, renewable, flexible and efficient energy resources. Most of the developing countries invest on this cost-effective energy source. Hydroturbines for hydroelectric power plants are tailor-made. Each turbine is designed and constructed according to the properties, namely the head and flow rate values of the specific water source. Therefore, a center (ETU Hydro-Center for Hydro Energy Research) for the design, manufacturing and performance tests of hydraulic turbines is established at TOBB University of Economics and Technology to promote research in this area. CFD aided hydraulic and structural design, geometry optimization, manufacturing and performance tests of hydraulic turbines are the areas of expertise of this center. In this paper, technical details of the design and construction of this one of a kind test facility in Turkey, is explained. All the necessary standards of IEC (International Electrotechnical Commission) are met since the test facility will act as a certificated test center for hydraulic turbines.

  11. Design, development and testing twin pulse tube cryocooler

    NASA Astrophysics Data System (ADS)

    Gour, Abhay Singh; Sagar, Pankaj; Karunanithi, R.

    2017-09-01

    The design and development of Twin Pulse Tube Cryocooler (TPTC) is presented. Both the coolers are driven by a single Linear Moving Magnet Synchronous Motor (LMMSM) with piston heads at both ends of the mover shaft. Magnetostatic analysis for flux line distribution was carried-out during design and development of LMMSM based pressure wave generator. Based on the performance of PWG, design of TPTC was carried out using Sage and Computational Fluid Dynamics (CFD) analysis. Detailed design, fabrication and testing of LMMSM, TPTC and their integration tests are presented in this paper.

  12. Bending Instabilities of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Silvestre, N.; Camotim, D.

    This paper presents an investigation on the buckling behaviour of single-walled carbon nanotubes (NTs) under bending and unveils several aspects concerning the dependence of critical bending curvature on the NT length. The buckling results are obtained by means of non-linear shell finite element analyses using ABAQUS code. It is shown that eigenvalue analyses do not give a correct prediction of the critical curvature of NTs under bending. Conversely, incremental-iterative non-linear analyses provide a better approximation to the molecular dynamics results due to the progressive ovalization of the NT cross-section under bending. For short NTs, the limit curvature drops with the increasing length mostly due to the decreasing influence of end effects. For moderate to long tubes, the limit curvature remains practically constant and independent on the tube length. An approximate formula based on the Brazier expression is proposed to predict the limit curvature.

  13. Vanguard/PLACE experiment system design and test plan

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.

    1973-01-01

    The design, development, and testing of the NASA-GFSC Position Location and Aircraft Communications Equipment (PLACE) at C band frequency are discussed. The equipment was installed on the USNS Vanguard. The tests involved a sea test to evalute the position-location, 2-way voice, and 2-way data communications capability of PLACE and a trilateration test to position-fix the ATS-5 satellite using the PLACE system.

  14. Design, testing and evaluation of latching end effector

    NASA Technical Reports Server (NTRS)

    Walker, B.; Vandersluis, R.

    1995-01-01

    The Latching End Effector (LEE) forms part of the Space Station Remote Manipulator System (SSRMS) for which Spar Aerospace Ltd, Space Systems Division is the prime contractor. The design, testing and performance evaluation of the Latching End Effector mechanisms is the subject of this paper focusing on: (1) ambient, thermal and vibration testing; (2) snare/rigidize performance testing and interaction during payload acquisition; and (3) latch/umbilical test results and performance.

  15. Holey fibers for low bend loss

    NASA Astrophysics Data System (ADS)

    Nakajima, Kazuhide; Saito, Kotaro; Yamada, Yusuke; Kurokawa, Kenji; Shimizu, Tomoya; Fukai, Chisato; Matsui, Takashi

    2013-12-01

    Bending-loss insensitive fiber (BIF) has proved an essential medium for constructing the current fiber to the home (FTTH) network. By contrast, the progress that has been made on holey fiber (HF) technologies provides us with novel possibilities including non-telecom applications. In this paper, we review recent progress on hole-assisted type BIF. A simple design consideration is overviewed. We then describe some of the properties of HAF including its mechanical reliability. Finally, we introduce some applications of HAF including to high power transmission. We show that HAF with a low bending loss has the potential for use in various future optical technologies as well as in the optical communication network.

  16. Environmental Analysis of the Air Bending Process

    NASA Astrophysics Data System (ADS)

    Kellens, Karel; Dewulf, Wim; Duflou, Joost R.

    2011-05-01

    This paper presents the results of a data collection effort, allowing to assess the overall environmental impact of the air bending process using the CO2PE!-Methodology. First the different modes of the air bending process are investigated, including both productive and non-productive modes. In particular consumption of electric power is recorded for the different modes. Subsequently, time studies allow determining the importance of productive and nonproductive modes of the involved process. The study demonstrates that the influence of standby losses can be substantial. In addition to life cycle analysis, in depth process analysis also provides insight in achievable environmental impact reducing measures towards machine tool builders and eco-design recommendations for product developers. The energy consumption of three different machine tool architectures are analysed and compared within this paper.

  17. Heat pipe design for sheath insulator reactor test

    SciTech Connect

    Miskolczy, G.; Lee, C.C.M. )

    1991-01-05

    A reactor experiment was designed to test the sheath insulator component of the thermionic fuel element (TFE) of a space power reactor. In this fully instrumented reactor test, two gas-controlled sodium heat pipes will be used to control the temperature of the sheath insulator specimens to which an external voltage will be applied. The heat pipes were designed with the aid of a computer program, which predicted performance. A demonstrator heat pipe was built and electrically tested. The test results agreed with the prediction as modeled by the computer program.

  18. Skylab Medical Experiments Altitude Test /SMEAT/ facility design and operation.

    NASA Technical Reports Server (NTRS)

    Hinners, A. H., Jr.; Correale, J. V.

    1973-01-01

    This paper presents the design approaches and test facility operation methods used to successfully accomplish a 56-day test for Skylab to permit evaluation of selected Skylab medical experiments in a ground test simulation of the Skylab environment with an astronaut crew. The systems designed for this test include the two-gas environmental control system, the fire suppression and detection system, equipment transfer lock, ground support equipment, safety systems, potable water system, waste management system, lighting and power system, television monitoring, communications and recreation systems, and food freezer.

  19. Skylab Medical Experiments Altitude Test /SMEAT/ facility design and operation.

    NASA Technical Reports Server (NTRS)

    Hinners, A. H., Jr.; Correale, J. V.

    1973-01-01

    This paper presents the design approaches and test facility operation methods used to successfully accomplish a 56-day test for Skylab to permit evaluation of selected Skylab medical experiments in a ground test simulation of the Skylab environment with an astronaut crew. The systems designed for this test include the two-gas environmental control system, the fire suppression and detection system, equipment transfer lock, ground support equipment, safety systems, potable water system, waste management system, lighting and power system, television monitoring, communications and recreation systems, and food freezer.

  20. Advanced Control Design for Wind Turbines; Part I: Control Design, Implementation, and Initial Tests

    SciTech Connect

    Wright, A. D.; Fingersh, L. J.

    2008-03-01

    The purpose of this report is to give wind turbine engineers information and examples of the design, testing through simulation, field implementation, and field testing of advanced wind turbine controls.

  1. Teaching beyond the Test: A Method for Designing Test-Preparation Classes

    ERIC Educational Resources Information Center

    Derrick, Deirdre

    2013-01-01

    Test-preparation classes that focus on skills will benefit students beyond the test by developing skills they can use at university. This article discusses the purposes of various tests and outlines how to design effective test-prep classes. Several practical activities are included, and an appendix provides information on common standardized…

  2. Design and test of lithium-alloy/iron monosulfide batteries

    SciTech Connect

    Chilenskas, A.A.; Biwer, R.L.; DeLuca, W.H.

    1986-04-01

    A program has been initiated by the Electric Power Research Institute to examine the feasibility of using the Li-alloy/FeS battery for electric-vehicle propulsion. In the first phase of the program, a joint effort between Argonne National Laboratory and Gould Reserch Center resulted in the design, fabrication, and testing of two full-scale 12-V modules and related battery components at Argonne's National Battery Test Laboratory. The design of the module and battery components was based upon a van battery design study supported by the US Department of Energy. The objective of the Phase I program was to provide test data to the battery developers applicable to cell and module development, insulated case design, heating/cooling subsystem design, and charger development.

  3. SMART Wind Turbine Rotor: Design and Field Test

    SciTech Connect

    Berg, Jonathan C.; Resor, Brian R.; Paquette, Joshua A.; White, Jonathan R.

    2014-01-29

    This report documents the design, fabrication, and testing of the SMART Rotor. This work established hypothetical approaches for integrating active aerodynamic devices (AADs) into the wind turbine structure and controllers.

  4. Execution of Multidisciplinary Design Optimization Approaches on Common Test Problems

    NASA Technical Reports Server (NTRS)

    Balling, R. J.; Wilkinson, C. A.

    1997-01-01

    A class of synthetic problems for testing multidisciplinary design optimization (MDO) approaches is presented. These test problems are easy to reproduce because all functions are given as closed-form mathematical expressions. They are constructed in such a way that the optimal value of all variables and the objective is unity. The test problems involve three disciplines and allow the user to specify the number of design variables, state variables, coupling functions, design constraints, controlling design constraints, and the strength of coupling. Several MDO approaches were executed on two sample synthetic test problems. These approaches included single-level optimization approaches, collaborative optimization approaches, and concurrent subspace optimization approaches. Execution results are presented, and the robustness and efficiency of these approaches an evaluated for these sample problems.

  5. The NASA computer aided design and test system

    NASA Technical Reports Server (NTRS)

    Gould, J. M.; Juergensen, K.

    1973-01-01

    A family of computer programs facilitating the design, layout, evaluation, and testing of digital electronic circuitry is described. CADAT (computer aided design and test system) is intended for use by NASA and its contractors and is aimed predominantly at providing cost effective microelectronic subsystems based on custom designed metal oxide semiconductor (MOS) large scale integrated circuits (LSIC's). CADAT software can be easily adopted by installations with a wide variety of computer hardware configurations. Its structure permits ease of update to more powerful component programs and to newly emerging LSIC technologies. The components of the CADAT system are described stressing the interaction of programs rather than detail of coding or algorithms. The CADAT system provides computer aids to derive and document the design intent, includes powerful automatic layout software, permits detailed geometry checks and performance simulation based on mask data, and furnishes test pattern sequences for hardware testing.

  6. Conceptual Design Report for the Extreme Ecosystems Test Chambers

    SciTech Connect

    C. Barnes; J. Beller; K. Caldwell; K. Croft; R. Cherry; W. Landman

    1998-12-01

    This conceptual design supports the creation of Extreme Ecosystems Test Chambers, which will replicate deep subsurface and subocean environments characterized by high pressure (2,000 psi) and subfreezing to high temperature (-4 to 300 degrees F) with differing chemical and saturation conditions. The design provides a system to support research and development that includes heat transfer, phase change issues in porous media, microbiology in extreme environments, and carbon sequestration and extraction. The initial system design is based on the research needs to support the commercial production of methane hydrates from subsurface sediments. The design provides for three pressure vessels: a Down Hole Test Vessel, a Vertical Multi-phase Test Vessel, and a Horizontal Multi-phase Test Vessel.

  7. MITG post-test analysis and design improvements

    SciTech Connect

    Schock, A.

    1983-01-01

    The design, performance analysis, and key attributes of the Modular Isotopic Thermoelectric Generator (MITG) were described in a 1981 IECEC paper; and the design, fabrication, and testing of prototypical MITG test assemblies were described in preceding papers in these proceedings. Each test assembly simulated a typical modular slice of the flight generator. The present paper describes a detailed thermal-stress analysis, which identified the causes of stress-related problems observed during the tests. It then describes how additional analyses were used to evaluate design changes to alleviate those problems. Additional design improvements are discussed in the next paper in these proceedings, which also describes revised fabrication procedures and updated performance estimates for the generator.

  8. Design and Testing of CPAS Main Deployment Bag Energy Modulator

    NASA Technical Reports Server (NTRS)

    Mollmann, Catherine

    2017-01-01

    During the developmental testing program for CPAS (Capsule Parachute Assembly System), the parachute system for the NASA Orion Crew Module, simulation revealed that high loads may be experienced by the pilot risers during the most devere deployment conditions. As the role of the pilot parachutes is to deploy the main parachutes, these high loads introduced the possibility of main deployment failure. In order to mitigate these high loads, a set of energy modulators was incorporated between the pilot riser and the main deployment bag. An extensive developmental program was implemented to ensure the adequacy of these energy modulators. After initial design comparisons, the energy modulator design was validated through slow-speed joint tests as well as through high-speed bungee tests. This paper documents the design, development, and results of multiple tests completed on the final design.

  9. Thermal design, analysis and testing of the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Foss, Richard A.; Smith, Dewey M.

    1987-01-01

    This paper briefly introduces the Halogen Occultation Experiment (HALOE) and describes the thermal requirements in some detail. The thermal design of the HALOE is described, together with the design process and the analytical techniques used to arrive at this design. The flight hardware has undergone environmental testing in a thermal vacuum chamber to validate the thermal design. The HALOE is a unique problem in thermal control due to its variable solar loading, its extremely sensitive optical components and the high degree of pointing accuracy required. This paper describes the flight hardware, the design process and its verification.

  10. Thermal design, analysis and testing of the Halogen Occultation Experiment

    NASA Technical Reports Server (NTRS)

    Foss, Richard A.; Smith, Dewey M.

    1987-01-01

    This paper briefly introduces the Halogen Occultation Experiment (HALOE) and describes the thermal requirements in some detail. The thermal design of the HALOE is described, together with the design process and the analytical techniques used to arrive at this design. The flight hardware has undergone environmental testing in a thermal vacuum chamber to validate the thermal design. The HALOE is a unique problem in thermal control due to its variable solar loading, its extremely sensitive optical components and the high degree of pointing accuracy required. This paper describes the flight hardware, the design process and its verification.

  11. Passive, achromatic, nearly isochronous bending system

    DOEpatents

    Douglas, David R.; Yunn, Byung C.

    2004-05-18

    A particle beam bending system having a geometry that applies active bending only beyond the chord of the orbit for any momentum component. Using this bending configuration, all momentum components emerge dispersed in position only; all trajectories are parallel by construction. Combining a pair of such bends with reflective symmetry produces a bend cell that is, by construction, achromatic to all orders. By the particular choice of 45.degree. individual bends, a pair of such achromats can be used as the basis of a 180.degree. recirculation arc. Other rational fractions of a full 180.degree. bend serve equally well (e.g., 2 bends/cell.times.90.degree./bend.times.1 cell /arc; 2 bends/cell.times.30.degree./bend.times.3 cells/arc, etc), as do combinations of multiple bending numerologies (e.g., 2 bends/cell.times.22.5.degree./bend.times.2 cells+2 bends/cell.times.45.degree./bend.times.1 cell). By the choice of entry pole face rotation of the first magnet and exit pole face rotation of the second magnet (with a value to be determined from the particular beam stability requirements imposed by the choice of bending angle and beam properties to be used in any particular application), desirable focusing properties can be introduced and beam stability can be insured.

  12. Preconceptual design of the new production reactor circulator test facility

    SciTech Connect

    Thurston, G.

    1990-06-01

    This report presents the results of a study of a new circulator test facility for the New Production Reactor Modular High-Temperature Gas-Cooled Reactor. The report addresses the preconceptual design of a stand-alone test facility with all the required equipment to test the Main Circulator/shutoff valve and Shutdown Cooling Circulator/shutoff valve. Each type of circulator will be tested in its own full flow, full power helium test loop. Testing will cover the entire operating range of each unit. The loop will include a test vessel, in which the circulator/valve will be mounted, and external piping. The external flow piping will include a throttle valve, flowmeter, and heat exchanger. Subsystems will include helium handling, helium purification, and cooling water. A computer-based data acquisition and control system will be provided. The estimated costs for the design and construction of this facility are included. 2 refs., 15 figs.

  13. Design and test of a magnetic thrust bearing

    NASA Technical Reports Server (NTRS)

    Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

    1993-01-01

    A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

  14. Design and test of a magnetic thrust bearing

    NASA Astrophysics Data System (ADS)

    Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

    A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

  15. Design and test of the microwave cavity in an optically-pumped Rubidium beam frequency standard

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Wang, Yan-Hui

    2015-01-01

    We are developing a compact rubidium atomic beam frequency standard with optical pumping and detection. The cavity for microwave interrogation is an important part of the clock. The cavity in our design is a Ramsey-type, E-bend one, which is the same as the conventional method in most cesium beam clocks. Requirements for the design are proposed based on the frequency shift associated with the cavity. The basic structure of the cavity is given by theoretical analysis and detailed dimensions are determined by means of electromagnetic field simulation with the help of commercial software. The cavity is manufactured and fabricated successfully. The preliminary test result of the cavity is given, which is in good agreement with the simulation. The resonant frequency is 6.835 GHz, equal to the clock transition frequency of 87Rb, and the loaded quality factor is 500. These values are adjustable with posts outside the cavity. Estimations on the Ramsey line width and several frequency shifts are made. Project supported by the National Natural Science Foundation of China (Grant No. 11174015).

  16. Designs and test results for three new rotational sensors

    USGS Publications Warehouse

    Jedlicka, P.; Kozak, J.T.; Evans, J.R.; Hutt, C.R.

    2012-01-01

    We discuss the designs and testing of three rotational seismometer prototypes developed at the Institute of Geophysics, Academy of Sciences (Prague, Czech Republic). Two of these designs consist of a liquid-filled toroidal tube with the liquid as the proof mass and providing damping; we tested the piezoelectric and pressure transduction versions of this torus. The third design is a wheel-shaped solid metal inertial sensor with capacitive sensing and magnetic damping. Our results from testing in Prague and at the Albuquerque Seismological Laboratory of the US Geological Survey of transfer function and cross-axis sensitivities are good enough to justify the refinement and subsequent testing of advanced prototypes. These refinements and new testing are well along.

  17. Design and test of the 172K fluidic rudder

    NASA Technical Reports Server (NTRS)

    Belsterling, C. A.

    1978-01-01

    Progress in the development of concepts for control of aircraft without moving parts or a separate source of power is described. The design and wind tunnel tests of a full scale fluidic rudder for a Cessna 172K aircraft, intended for subsequent flight tests were documented. The 172K fluidic rudder was designed to provide a control force equivalent to 3.3 degrees of deflection of the conventional rudder. In spite of an extremely thin airfoil, cascaded fluidic amplifiers were built to fit, with the capacity for generating the required level of control force. Wind tunnel tests demonstrated that the principles of lift control using ram air power are sound and reliable under all flight conditions. The tests also demonstrated that the performance of the 172K fluidic rudder is not acceptable for flight tests until the design of the scoop is modified to prevent interference with the lift control phenomenon.

  18. Conceptual design of the MHD Engineering Test Facility

    NASA Technical Reports Server (NTRS)

    Bents, D. J.; Bercaw, R. W.; Burkhart, J. A.; Mroz, T. S.; Rigo, H. S.; Pearson, C. V.; Warinner, D. K.; Hatch, A. M.; Borden, M.; Giza, D. A.

    1981-01-01

    The reference conceptual design of the MHD engineering test facility, a prototype 200 MWe coal-fired electric generating plant designed to demonstrate the commerical feasibility of open cycle MHD is summarized. Main elements of the design are identified and explained, and the rationale behind them is reviewed. Major systems and plant facilities are listed and discussed. Construction cost and schedule estimates are included and the engineering issues that should be reexamined are identified.

  19. Spacecraft System Integration and Test: SSTI Lewis critical design audit

    NASA Technical Reports Server (NTRS)

    Brooks, R. P.; Cha, K. K.

    1995-01-01

    The Critical Design Audit package is the final detailed design package which provides a comprehensive description of the SSTI mission. This package includes the program overview, the system requirements, the science and applications activities, the ground segment development, the assembly, integration and test description, the payload and technology demonstrations, and the spacecraft bus subsystems. Publication and presentation of this document marks the final requirements and design freeze for SSTI.

  20. High-Temperature Gas-Cooled Test Reactor Point Design

    SciTech Connect

    Sterbentz, James William; Bayless, Paul David; Nelson, Lee Orville; Gougar, Hans David; Kinsey, James Carl; Strydom, Gerhard; Kumar, Akansha

    2016-04-01

    A point design has been developed for a 200 MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched UCO fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technological readiness level, licensing approach and costs.