Computational fluid dynamic (CFD) investigation of thermal uniformity in a thermal cycling based calibration chamber for MEMS

NASA Astrophysics Data System (ADS)

Gui, Xulong; Luo, Xiaobing; Wang, Xiaoping; Liu, Sheng

2015-12-01

Micro-electrical-mechanical system (MEMS) has become important for many industries such as automotive, home appliance, portable electronics, especially with the emergence of Internet of Things. Volume testing with temperature compensation has been essential in order to provide MEMS based sensors with repeatability, consistency, reliability, and durability, but low cost. Particularly, in the temperature calibration test, temperature uniformity of thermal cycling based calibration chamber becomes more important for obtaining precision sensors, as each sensor is different before the calibration. When sensor samples are loaded into the chamber, we usually open the door of the chamber, then place fixtures into chamber and mount the samples on the fixtures. These operations may affect temperature uniformity in the chamber. In order to study the influencing factors of sample-loading on the temperature uniformity in the chamber during calibration testing, numerical simulation work was conducted first. Temperature field and flow field were simulated in empty chamber, chamber with open door, chamber with samples, and chamber with fixtures, respectively. By simulation, it was found that opening chamber door, sample size and number of fixture layers all have effects on flow field and temperature field. By experimental validation, it was found that the measured temperature value was consistent with the simulated temperature value.

Energy conservation in two wheeler head tube welding fixture by modeling

NASA Astrophysics Data System (ADS)

Kamalanathan, S.; Guruprasad, B.; Elango, A.

2018-05-01

Energy conservation in automotive industry plays a significant role to increase the productivity which reduces the Men, Material, and Machinery. The Automotive industry sector is one of the major sector which works in two or more times of loading of work pieces in welding fixture. It consumes more energy. This project focuses on reduce the energy consumption by applying single time loading of work pieces with minimum number of labours, machine and reduces scrap. Welding fixtures are designed for the components which are difficult to weld in normal way or without any holding unit. The fixture is to be designed for the two wheeler head tube assembly which is to be welded with its companion for its application. It is demonstrated by modelling in Uni-graphics Software and FEA analysis will be done by ANSYS and experimentally products are tested and execute in industry. A code of practice suggested establishing acceptable standard for energy used in Automotive industry.

Sinking and fit of abutment of locking taper implant system

PubMed Central

Moon, Seung-Jin; Kim, Hee-Jung; Son, Mee-Kyoung

2009-01-01

STATEMENT OF PROBLEM Unlike screw-retention type, fixture-abutment retention in Locking taper connection depends on frictional force so it has possibility of abutment to sink. PURPOSE In this study, Bicon® Implant System, one of the conical internal connection implant system, was used with applying loading force to the abutments connected to the fixture. Then the amount of sinking was measured. MATERIAL AND METHODS 10 Bicon® implant fixtures were used. First, the abutment was connected to the fixture with finger force. Then it was tapped with a mallet for 3 times and loads of 20 kg corresponding to masticatory force using loading application instrument were applied successively. The abutment state, slightly connected to the fixture without pressure was considered as a reference length, and every new abutment length was measured after each load's step was added. The amount of abutment sinking (mm) was gained by subtracting the length of abutment-fixture under each loading condition from reference length. RESULTS It was evident, that the amount of abutment sinking in Bicon® Implant System increased as loads were added. When loads of 20 kg were applied more than 5 - 7 times, sinking stopped at 0.45 ± 0.09 mm. CONCLUSION Even though locking taper connection type implant shows good adaption to occlusal force, it has potential for abutment sinking as loads are given. When locking taper connection type implant is used, satisfactory loads are recommended for precise abutment location. PMID:21165262

A Single-Block TRL Test Fixture for the Cryogenic Characterization of Planar Microwave Components

NASA Technical Reports Server (NTRS)

Mejia, M.; Creason, A. S.; Toncich, S. S.; Ebihara, B. T.; Miranda, F. A.

1996-01-01

The High-Temperature-Superconductivity (HTS) group of the RF Technology Branch, Space Electronics Division, is actively involved in the fabrication and cryogenic characterization of planar microwave components for space applications. This process requires fast, reliable, and accurate measurement techniques not readily available. A new calibration standard/test fixture that enhances the integrity and reliability of the component characterization process has been developed. The fixture consists of 50 omega thru, reflect, delay, and device under test gold lines etched onto a 254 microns (0.010 in) thick alumina substrate. The Thru-Reflect-Line (TRL) fixture was tested at room temperature using a 30 omega, 7.62 mm (300 mil) long, gold line as a known standard. Good agreement between the experimental data and the data modelled using Sonnet's em(C) software was obtained for both the return (S(sub 11)) and insertion (S( 21)) losses. A gold two-pole bandpass filter with a 7.3 GHz center frequency was used as our Device Under Test (DUT), and the results compared with those obtained using a Short-Open-Load-Thru (SOLT) calibration technique.

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.

Cryogenic Temperature-Gradient Foam/Substrate Tensile Tester

NASA Technical Reports Server (NTRS)

Vailhe, Christophe

2003-01-01

The figure shows a fixture for measuring the tensile strength of the bond between an aluminum substrate and a thermally insulating polymeric foam. The specimen is meant to be representative of insulating foam on an aluminum tank that holds a cryogenic liquid. Prior to the development of this fixture, tensile tests of this type were performed on foam/substrate specimens immersed in cryogenic fluids. Because the specimens were cooled to cryogenic temperatures throughout their thicknesses, they tended to become brittle and to fracture at loads below true bond tensile strengths. The present fixture is equipped to provide a thermal gradient from cryogenic temperature at the foam/substrate interface to room temperature on the opposite foam surface. The fixture includes an upper aluminum block at room temperature and a lower aluminum block cooled to -423 F (approx. -253 C) by use of liquid helium. In preparation for a test, the metal outer surface (the lower surface) of a foam/substrate specimen is bonded to the lower block and the foam outer surface (the upper surface) of the specimen is bonded to the upper block. In comparison with the through-the-thickness cooling of immersion testing, the cryogenic-to-room-temperature thermal gradient that exists during testing on this fixture is a more realistic approximation of the operational thermal condition of sprayed insulating foam on a tank of cryogenic liquid. Hence, tensile tests performed on this fixture provide more accurate indications of operational bond tensile strengths. In addition, the introduction of the present fixture reduces the cost of testing by reducing the amount of cryogenic liquid consumed and the time needed to cool a specimen.

Test program, helium II orbital resupply coupling

NASA Technical Reports Server (NTRS)

Hyatt, William S.

1991-01-01

The full scope of this program was to have included development tests, design and production of custom test equipment and acceptance and qualification testing of prototype and protoflight coupling hardware. This program was performed by Ball Aerospace Systems Division, Boulder, Colorado until its premature termination in May 1991. Development tests were performed on cryogenic face seals and flow control devices at superfluid helium (He II) conditions. Special equipment was developed to allow quantified leak detection at large leak rates up to 8.4 x 10(exp -4) SCCS. Two major fixtures were developed and characterized: The Cryogenic Test Fixture (CTF) and the Thermal Mismatch Fixture (Glovebox). The CTF allows the coupling hardware to be filled with liquid nitrogen (LN2), liquid helium (LHe) or sub-cooled liquid helium when hardware flow control valves are either open or closed. Heat leak measurements, internal and external helium leakage measurements, cryogenic proof pressure tests and external load applications are performed in this fixture. Special reusable MLI closures were developed to provide repeatable installations in the CTF. The Thermal Mismatch Fixture allows all design configurations of coupling hardware to be engaged and disengaged while measuring applied forces and torques. Any two hardware components may be individually thermally preconditioned within the range of 117 deg K to 350 deg K prior to engage/disengage cycling. This verifies dimensional compatibility and operation when thermally mismatched. A clean, dry GN2 atmosphere is maintained in the fixture at all times. The first shipset of hardware was received, inspected and cycled at room temperature just prior to program termination.

Redesign of a fixture mount to be used as an impression coping and a provisional abutment as well

PubMed Central

Chang, Glenn Hsuan-Chen; Tian, Chen; Hung, Yuen-Siang

2011-01-01

Purpose: An integrated fixture mount/impression coping/ temporary abutment can provide many advantages for immediate loading of dental implants, such as simpler procedure, less chair time, cost reduction, and comfort for the patients. Materials and Methods: A newly designed dental implant fixture mount (DIFMA) can be used as an impression coping for taking an immediate impression. An immediate load provisional prosthesis can then be fabricated shortly after implant placement to immediately load the implants. This fixture mount can also serve as a temporary abutment for immediate chair-side fabrication of provisional prosthesis. Two clinical cases are presented. Results: A clinical case utilizing the fixture mount abutment (DIFMA)/implant assembly is presented. The precision of fitting between the impression copings and implants is secured with this system. The chair time for taking an immediate impression is greatly reduced. Less cost for the restoration is provided and patient comfort is delivered. Conclusions: More patient satisfaction can be conferred by employing the fixture mount in the process of immediate impression taking and as an immediate provisional abutment. PMID:22090763

Reliability and Failure Modes of a Hybrid Ceramic Abutment Prototype.

PubMed

Silva, Nelson Rfa; Teixeira, Hellen S; Silveira, Lucas M; Bonfante, Estevam A; Coelho, Paulo G; Thompson, Van P

2018-01-01

A ceramic and metal abutment prototype was fatigue tested to determine the probability of survival at various loads. Lithium disilicate CAD-milled abutments (n = 24) were cemented to titanium sleeve inserts and then screw attached to titanium fixtures. The assembly was then embedded at a 30° angle in polymethylmethacrylate. Each (n = 24) was restored with a resin-cemented machined lithium disilicate all-ceramic central incisor crown. Single load (lingual-incisal contact) to failure was determined for three specimens. Fatigue testing (n = 21) was conducted employing the step-stress method with lingual mouth motion loading. Failures were recorded, and reliability calculations were performed using proprietary software. Probability Weibull curves were calculated with 90% confidence bounds. Fracture modes were classified with a stereomicroscope, and representative samples imaged with scanning electron microscopy. Fatigue results indicated that the limiting factor in the current design is the fatigue strength of the abutment screw, where screw fracture often leads to failure of the abutment metal sleeve and/or cracking in the implant fixture. Reliability for completion of a mission at 200 N load for 50K cycles was 0.38 (0.52% to 0.25 90% CI) and for 100K cycles was only 0.12 (0.26 to 0.05)-only 12% predicted to survive. These results are similar to those from previous studies on metal to metal abutment/fixture systems where screw failure is a limitation. No ceramic crown or ceramic abutment initiated fractures occurred, supporting the research hypothesis. The limiting factor in performance was the screw failure in the metal-to-metal connection between the prototyped abutment and the fixture, indicating that this configuration should function clinically with no abutment ceramic complications. The combined ceramic with titanium sleeve abutment prototype performance was limited by the fatigue degradation of the abutment screw. In fatigue, no ceramic crown or ceramic abutment components failed, supporting the research hypothesis with a reliability similar to that of all-metal abutment fixture systems. A lithium disilcate abutment with a Ti alloy sleeve in combination with an all-ceramic crown should be expected to function clinically in a satisfactory manner. © 2016 by the American College of Prosthodontists.

1001518

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

1001519

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

1001520

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

1001521

NASA Image and Video Library

2010-09-01

DEVELOPMENT TESTING BEING CONDUCTED AT THE REQUEST OF THE MSFC DYNAMICS, LOADS, AND STRENGTH BRANCH (EV31) TO STUDY THE FAILURE BEHAVIOR OF FASTENERS SUBJECTED TO COMBINED SHEAR AND TENSION LOADING. THE DATA FROM THIS TESTING WILL BE USED TO DEVELOP APPROPRIATE STRUCTURAL ANALYSIS METHODS AS PART OF A FASTENER STANDARDS EFFORT SPONSORED BY THE NASA ENGINEERING SAFETY CENTER (NESC). THE TEST FIXTURE WAS DESIGNED AND FABRICATED THROUGH THE MSFC MECHANICAL FABRICATION BRANCH (ES23). THE TESTING ORGANIZATION IS THE MSFC MATERIALS TEST BRANCH (EM10).

Materials research for high-speed civil transport and generic hypersonics: Composites durability

NASA Technical Reports Server (NTRS)

Allen-Lilly, Heather; Cregger, Eric; Hoffman, Daniel; Mccool, Jim

1995-01-01

This report covers a portion of an ongoing investigation of the durability of composites for the High Speed Civil Transport (HSCT) program. Candidate HSCT composites need to possess the high-temperature capability required for supersonic flight. This program was designed to initiate the design, analysis, fabrication, and testing of equipment intended for use in validating the long-term durability of materials for the HSCT. This equipment includes thermally actuated compression and tension fixtures, hydraulic-actuated reversible load fixtures, and thermal chambers. This equipment can be used for the durability evaluation of both composite and adhesive materials. Thermally actuated fixtures are recommended for fatigue cycling when long-term thermomechanical fatigue (TMF) data are required on coupon-sized tension or compression specimens. Long term durability testing plans for polymer matrix composite specimens are included.

F-15B in flight with X-33 Thermal Protection Systems (TPS) on Flight Test Fixture

NASA Technical Reports Server (NTRS)

1998-01-01

In-flight photo of the NASA F-15B used in tests of the X-33 Thermal Protection System (TPS) materials. Flying at subsonic speeds, the F-15B tests measured the air loads on the proposed X-33 protective materials. In contrast, shock loads testing investigated the local impact of the supersonic shock wave itself on the TPS materials. Similar tests had been done in 1985 for the space shuttle tiles, using an F-104 aircraft.

F-15B in flight with X-33 Thermal Protection Systems (TPS) on Flight Test Fixture

NASA Image and Video Library

1998-05-14

In-flight photo of the NASA F-15B used in tests of the X-33 Thermal Protection System (TPS) materials. Flying at subsonic speeds, the F-15B tests measured the air loads on the proposed X-33 protective materials. In contrast, shock loads testing investigated the local impact of the supersonic shock wave itself on the TPS materials. Similar tests had been done in 1985 for the space shuttle tiles, using an F-104 aircraft.

Calculations of the Acceleration of Centrifugal Loading on Adherent Cells

NASA Astrophysics Data System (ADS)

Chen, Kang; Song, Yang; Liu, Qing; Zhang, Chunqiu

2017-07-01

Studies have shown that the morphology and function of living cells are greatly affected by the state of different high acceleration. Based on the centrifuge, we designed a centrifugal cell loading machine for the mechanical biology of cells under high acceleration loading. For the machine, the feasibility of the experiment was studied by means of constant acceleration or variable acceleration loading in the Petri dish fixture and/or culture flask. Here we analyzed the distribution of the acceleration of the cells with the change of position and size of the culturing device quantitatively. It is obtained that Petri dish fixture and/or culture flask can be used for constant acceleration loading by experiments; the centripetal acceleration of the adherent cells increases with the increase of the distance between the rotor center of the centrifuge and the fixture of the Petri dish and the size of the fixture. It achieves the idea that the general biology laboratory can conduct the study of mechanical biology at high acceleration. It also provides a basis for more accurate study of the law of high acceleration on mechanobiology of cells.

Evaluation of stability of interface between CCM (Co-Cr-Mo) UCLA abutment and external hex implant.

PubMed

Yoon, Ki-Joon; Park, Young-Bum; Choi, Hyunmin; Cho, Youngsung; Lee, Jae-Hoon; Lee, Keun-Woo

2016-12-01

The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant. Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of 1.0 × 10 6 cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05. Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups ( P >.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens. Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment.

Method and apparatus for determining weldability of thin sheet metal

DOEpatents

Goodwin, Gene M.; Hudson, Joseph D.

1988-01-01

A fixture is provided for testing thin sheet metal specimens to evaluate hot-cracking sensitivity for determining metal weldability on a heat-to-heat basis or through varying welding parameters. A test specimen is stressed in a first direction with a load selectively adjustable over a wide range and then a weldment is passed along over the specimen in a direction transverse to the direction of strain to evaluate the hot-cracking characteristics of the sheet metal which are indicative of the weldability of the metal. The fixture provides evaluations of hot-cracking sensitivity for determining metal weldability in a highly reproducible manner with minimum human error.

Titanium Honeycomb Panel Testing

NASA Technical Reports Server (NTRS)

Richards, W. Lance; Thompson, Randolph C.

1996-01-01

Thermal-mechanical tests were performed on a titanium honeycomb sandwich panel to experimentally validate the hypersonic wing panel concept and compare test data with analysis. Details of the test article, test fixture development, instrumentation, and test results are presented. After extensive testing to 900 deg. F, non-destructive evaluation of the panel has not detected any significant structural degradation caused by the applied thermal-mechanical loads.

Aerospace Threaded Fastener Strength in Combined Shear and Tension Loading

NASA Technical Reports Server (NTRS)

Steeve, B. E.; Wingate, R. J.

2012-01-01

A test program was initiated by Marshall Space Flight Center and sponsored by the NASA Engineering and Safety Center to characterize the failure behavior of a typical high-strength aerospace threaded fastener under a range of shear to tension loading ratios for both a nut and an insert configuration where the shear plane passes through the body and threads, respectively. The testing was performed with a customized test fixture designed to test a bolt with a single shear plane at a discrete range of loading angles. The results provide data to compare against existing combined loading failure criteria and to quantify the bolt strength when the shear plane passes through the threads.

46 CFR 154.406 - Design loads for cargo tanks and fixtures: General.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Design loads for cargo tanks and fixtures: General. 154.406 Section 154.406 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment...

46 CFR 154.406 - Design loads for cargo tanks and fixtures: General.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Design loads for cargo tanks and fixtures: General. 154.406 Section 154.406 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment...

46 CFR 154.406 - Design loads for cargo tanks and fixtures: General.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Design loads for cargo tanks and fixtures: General. 154.406 Section 154.406 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo Containment...

Evaluation of stability of interface between CCM (Co-Cr-Mo) UCLA abutment and external hex implant

PubMed Central

Yoon, Ki-Joon; Park, Young-Bum; Choi, Hyunmin; Cho, Youngsung; Lee, Jae-Hoon

2016-01-01

PURPOSE The purpose of this study is to evaluate the stability of interface between Co-Cr-Mo (CCM) UCLA abutment and external hex implant. MATERIALS AND METHODS Sixteen external hex implant fixtures were assigned to two groups (CCM and Gold group) and were embedded in molds using clear acrylic resin. Screw-retained prostheses were constructed using CCM UCLA abutment and Gold UCLA abutment. The external implant fixture and screw-retained prostheses were connected using abutment screws. After the abutments were tightened to 30 Ncm torque, 5 kg thermocyclic functional loading was applied by chewing simulator. A target of 1.0 × 106 cycles was applied. After cyclic loading, removal torque values were recorded using a driving torque tester, and the interface between implant fixture and abutment was evaluated by scanning electronic microscope (SEM). The means and standard deviations (SD) between the CCM and Gold groups were analyzed with independent t-test at the significance level of 0.05. RESULTS Fractures of crowns, abutments, abutment screws, and fixtures and loosening of abutment screws were not observed after thermocyclic loading. There were no statistically significant differences at the recorded removal torque values between CCM and Gold groups (P>.05). SEM analysis revealed that remarkable wear patterns were observed at the abutment interface only for Gold UCLA abutments. Those patterns were not observed for other specimens. CONCLUSION Within the limit of this study, CCM UCLA abutment has no statistically significant difference in the stability of interface with external hex implant, compared with Gold UCLA abutment. PMID:28018564

Carbon-carbon primary structure for SSTO vehicles

NASA Astrophysics Data System (ADS)

Croop, Harold C.; Lowndes, Holland B.

1997-01-01

A hot structures development program is nearing completion to validate use of carbon-carbon composite structure for primary load carrying members in a single-stage-to-orbit, or SSTO, vehicle. A four phase program was pursued which involved design development and fabrication of a full-scale wing torque box demonstration component. The design development included vehicle and component selection, design criteria and approach, design data development, demonstration component design and analysis, test fixture design and analysis, demonstration component test planning, and high temperature test instrumentation development. The fabrication effort encompassed fabrication of structural elements for mechanical property verification as well as fabrication of the demonstration component itself and associated test fixturing. The demonstration component features 3D woven graphite preforms, integral spars, oxidation inhibited matrix, chemical vapor deposited (CVD) SiC oxidation protection coating, and ceramic matrix composite fasteners. The demonstration component has been delivered to the United States Air Force (USAF) for testing in the Wright Laboratory Structural Test Facility, WPAFB, OH. Multiple thermal-mechanical load cycles will be applied simulating two atmospheric cruise missions and one orbital mission. This paper discusses the overall approach to validation testing of the wing box component and presents some preliminary analytical test predictions.

Removal torque evaluation of three different abutment screws for single implant restorations after mechanical cyclic loading.

PubMed

Paepoemsin, T; Reichart, P A; Chaijareenont, P; Strietzel, F P; Khongkhunthian, P

2016-01-01

The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer's recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, P<.05). After cyclic loading, removal torque in all groups decreased significantly (P<.05). Group C revealed significantly less removal torque than groups A and B (P<.005). Tensile force in all groups significantly increased after cyclic loading (P<.05), group A had significantly less tensile force than groups B and C (P<.005). Removal torque reduced significantly after cyclic loading. Before cyclic loading, tapered screws maintained more preload than did flat head screws. After cyclic loading, tapered and flat head screws maintained even amounts of preload. The tensile force that dislodged abutment from implant fixture increased immensely after cyclic loading.

Removal torque evaluation of three different abutment screws for single implant restorations after mechanical cyclic loading

PubMed Central

PAEPOEMSIN, T.; REICHART, P. A.; CHAIJAREENONT, P.; STRIETZEL, F. P.; KHONGKHUNTHIAN, P.

2016-01-01

SUMMARY Purpose The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. Methods The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer’s recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. Results Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, P<.05). After cyclic loading, removal torque in all groups decreased significantly (P<.05). Group C revealed significantly less removal torque than groups A and B (P<.005). Tensile force in all groups significantly increased after cyclic loading (P<.05), group A had significantly less tensile force than groups B and C (P<.005). Conclusions Removal torque reduced significantly after cyclic loading. Before cyclic loading, tapered screws maintained more preload than did flat head screws. After cyclic loading, tapered and flat head screws maintained even amounts of preload. The tensile force that dislodged abutment from implant fixture increased immensely after cyclic loading. PMID:28042450

Overview of the 6 Meter HIAD Inflatable Structure and Flexible TPS Static Load Test Series

NASA Technical Reports Server (NTRS)

Swanson, Greg; Kazemba, Cole; Johnson, Keith; Calomino, Anthony; Hughes, Steve; Cassell, Alan; Cheatwood, Neil

2014-01-01

To support NASAs long term goal of landing humans on Mars, technologies which enable the landing of heavy payloads are being developed. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current launch vehicle fairing limitations. Therefore, past and present technologies are now being explored to provide a mass and volume efficient solution to atmospheric entry, including Hypersonic Inflatable Aerodynamic Decelerators (HIADs). At the beginning of 2014, a 6m HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify the designs structural performance. The 6m HIAD structure was constructed in a stacked toroid configuration using nine inflatable torus segments composed of fiber reinforced thin films, which were joined together using adhesives and high strength textile woven structural straps to help distribute the loads throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials to protect the inflatable structure from heat loads that would be seen during atmospheric entry. To perform the static load test series, a custom test fixture was constructed. The fixture consisted of a structural tub rim with enough height to allow for displacement of the inflatable structure as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The centerbody of the inflatable structure was attached to a pedestal mount as seen in Figure 1. Using an impermeable membrane seal draped over the test article, partial vacuum was pulled beneath the HIAD, resulting in a uniform static pressure load applied to the outer surface. During the test series an extensive amount of instrumentation was used to provide many data sets including: deformed shape, shoulder deflection, strap loads, cord loads, inflation pressures, and applied static load.In this overview, the 6m HIAD static load test series will be discussed in detail, including the 6m HIAD inflatable structure and flexible TPS design, test setup and execution, and finally initial results and conclusions from the test series.

Test Fixture for Determination of Energy Absorbing Capabilities of Composite Materials

NASA Technical Reports Server (NTRS)

Lavoie, J. Andre (Inventor); Jackson, Karen E. (Inventor); Morton, John (Inventor)

1998-01-01

The present invention provides a fixture for supporting an elongated specimen for crush testing. The fixture comprises a base plate. four guiding rods, a sliding plate, four support rods and two collars. The guiding rods connect to the base plate and extend in a direction substantially perpendicular to the base plate. The sliding plate has linear bearings which encircle the guiding rods and enable translation of the sliding plate along the axis of each guiding rod. The four supporting rods mount to the base plate and also extend in a direction substantially perpendicular to the base plate. Each support rod has a keyway for a wedge which contacts the elongated specimen and holds the specimen in place during crushing. Each collar lies above the sliding plate and holds a pair of support rods on their ends opposite the ends connected to the base plate. A spherical bearing sits on top of the sliding plate and transfers an applied load to the sliding plate, which moves downward and crushes the elongated specimen.

Test fixture for determination of energy absorbing capabilities of composite materials

NASA Technical Reports Server (NTRS)

Lavoie, J. Andre (Inventor); Jackson, Karen E. (Inventor); Morton, John (Inventor)

1994-01-01

The present invention provides a fixture for supporting an elongated specimen for crush testing. The fixture comprises a base plate, four guiding rods, a sliding plate, four support rods and two collars. The guiding rods connect to the base plate and extend in a direction substantially perpendicular to the base plate. The sliding plate has linear bearings which encircle the guiding rods and enable translation of the sliding plate along the axis of each guiding rod. The four supporting rods mount to the base plate and also extend in a direction substantially perpendicular to the base plate. Each support rod has a keyway for a wedge which contacts the elongated specimen and holds the specimen in place during crushing. Each collar lies above the sliding plate and holds a pair of support rods on their ends opposite the ends connected to the base plate. A spherical bearing sits on top of the sliding plate and transfers an applied load to the sliding plate, which moves downward and crushes the elongated specimen.

Buckling test of a 3-meter-diameter corrugated graphite-epoxy ring-stiffened cylinder

NASA Technical Reports Server (NTRS)

Davis, R. C.

1982-01-01

A three m diameter by three m long corrugated cylindrical shell with external stiffening rings was tested to failure by buckling. The corrugation geometry for the graphite epoxy composite cylinder wall was optimized to withstand a compressive load producing an ultimate load intensity of 157.6 kN/m without buckling. The test method used to produce the design load intensity was to mount the specimen as a cantilevered cylinder and apply a pure bending moment to the end. A load introduction problem with the specimen was solved by using the BOSOR 4 shell of revolution computer code to analyze the shell and attached loading fixtures. The cylinder test loading achieved was 101 percent of design ultimate, and the resulting mass per unit of shell wall area was 1.96 kg/sq m.

Prosthetic aspects of osseointegrated fixtures supporting overdentures. A 4-year report.

PubMed

Naert, I; Quirynen, M; Theuniers, G; van Steenberghe, D

1991-05-01

Eighty-six consecutive patients, provided with 84 resilient and two nonresilient overdentures (six in the upper and 80 in the lower jaw), were examined. The overdentures were supported by a total of 173 osseointegrated titanium fixtures (the standard Branemark abutment), with a mean loading time of 19.1 months (range 4 to 48 months). In each jaw only two fixtures anchored the overdentures. No failures occurred during the observation period but two fixtures were lost before loading. The radiographic annual bone loss around fixtures in the lower jaw was -0.8 mm for the first year and less than -0.1 mm for the following years. The change in marginal bone height did not correlate with parameters such as the occlusion and articulation pattern, the presence or absence of a soft liner around the abutments, and the magnitude of the interabutment distance. The patients' reactions to overdenture treatment were, on the whole, positive concerning chewing function, phonetics, and comfort. The need for maintenance care of the clip-bar attachment was minimal.

Reducing Unsteady Loads on a Piggyback Miniature Submarine

NASA Technical Reports Server (NTRS)

Lin, John

2009-01-01

A small, simple fixture has been found to be highly effective in reducing destructive unsteady hydrodynamic loads on a miniature submarine that is attached in piggyback fashion to the top of a larger, nuclear-powered, host submarine. The fixture, denoted compact ramp, can be installed with minimal structural modification, and the use of it does not entail any change in submarine operations.

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.

Stress analysis and buckling of J-stiffened graphite-epoxy panel

NASA Technical Reports Server (NTRS)

Davis, R. C.

1980-01-01

A graphite epoxy shear panel with bonded on J stiffeners was investigated. The panel, loaded to buckling in a picture frame shear test is described. Two finite element models, each of which included the doubler material bonded to the panel skin under the stiffeners and at the panel edges, were used to make a stress analysis of the panel. The shear load distributions in the panel from two commonly used boundary conditions, applied shear load and applied displacement, were compared with the results from one of the finite element models that included the picture frame test fixture.

Free-free and fixed base modal survey tests of the Space Station Common Module Prototype

NASA Technical Reports Server (NTRS)

Driskill, T. C.; Anderson, J. B.; Coleman, A. D.

1992-01-01

This paper describes the testing aspects and the problems encountered during the free-free and fixed base modal surveys completed on the original Space Station Common Module Prototype (CMP). The CMP is a 40-ft long by 14.5-ft diameter 'waffle-grid' cylinder built by the Boeing Company and housed at the Marshall Space Flight Center (MSFC) near Huntsville, AL. The CMP modal survey tests were conducted at MSFC by the Dynamics Test Branch. The free-free modal survey tests (June '90 to Sept. '90) included interface verification tests (IFVT), often referred to as impedance measurements, mass-additive testing and linearity studies. The fixed base modal survey tests (Feb. '91 to April '91), including linearity studies, were conducted in a fixture designed to constrain the CMP in 7 total degrees-of-freedom at five trunnion interfaces (two primary, two secondary, and the keel). The fixture also incorporated an airbag off-load system designed to alleviate the non-linear effects of friction in the primary and secondary trunnion interfaces. Numerous test configurations were performed with the objective of providing a modal data base for evaluating the various testing methodologies to verify dynamic finite element models used for input to coupled load analysis.

RF Testing Of Microwave Integrated Circuits

NASA Technical Reports Server (NTRS)

Romanofsky, R. R.; Ponchak, G. E.; Shalkhauser, K. A.; Bhasin, K. B.

1988-01-01

Fixtures and techniques are undergoing development. Four test fixtures and two advanced techniques developed in continuing efforts to improve RF characterization of MMIC's. Finline/waveguide test fixture developed to test submodules of 30-GHz monolithic receiver. Universal commercially-manufactured coaxial test fixture modified to enable characterization of various microwave solid-state devices in frequency range of 26.5 to 40 GHz. Probe/waveguide fixture is compact, simple, and designed for non destructive testing of large number of MMIC's. Nondestructive-testing fixture includes cosine-tapered ridge, to match impedance wavequide to microstrip. Advanced technique is microwave-wafer probing. Second advanced technique is electro-optical sampling.

Coaxial test fixture

DOEpatents

Praeg, W.F.

1984-03-30

This invention pertains to arrangements for performing electrical tests on contact material samples, and in particular for testing contact material test samples in an evacuated environment under high current loads. Frequently, it is desirable in developing high-current separable contact material, to have at least a preliminary analysis of selected candidate conductor materials. Testing of material samples will hopefully identify materials unsuitable for high current electrical contact without requiring incorporation of the materials into a completed and oftentimes complex structure.

Structural Stability of a Stiffened Aluminum Fuselage Panel Subjected to Combined Mechanical and Internal Pressure Loads

NASA Technical Reports Server (NTRS)

Rouse, Marshall; Young, Richard D.; Gehrki, Ralph R.

2003-01-01

Results from an experimental and analytical study of a curved stiffened aluminum panel subjected to combined mechanical and internal pressure loads are presented. The panel loading conditions were simulated using a D-box test fixture. Analytical buckling load results calculated from a finite element analysis are presented and compared to experimental results. Buckling results presented indicate that the buckling load of the fuselage panel is significantly influenced by internal pressure loading. The experimental results suggest that the stress distribution is uniform in the panel prior to buckling. Nonlinear finite element analysis results correlates well with experimental results up to buckling.

Theoretical, Experimental, and Computational Evaluation of Disk-Loaded Circular Wave Guides

NASA Technical Reports Server (NTRS)

Wallett, Thomas M.; Qureshi, A. Haq

1994-01-01

A disk-loaded circular wave guide structure and test fixture were fabricated. The dispersion characteristics were found by theoretical analysis, experimental testing, and computer simulation using the codes ARGUS and SOS. Interaction impedances were computed based on the corresponding dispersion characteristics. Finally, an equivalent circuit model for one period of the structure was chosen using equivalent circuit models for cylindrical wave guides of different radii. Optimum values for the discrete capacitors and inductors describing discontinuities between cylindrical wave guides were found using the computer code TOUCHSTONE.

Note on performance of tapered grip tensile loading devices

NASA Technical Reports Server (NTRS)

Jones, M. H.; Brown, W. F., Jr.

1975-01-01

Alignment results are presented in terms of percent bending for a quick release, tapered grip, tensile loading device that has been proposed for testing sharply notched specimens of aluminum and magnesium alloys by a Task Group of the ASTM Committee E-24 on Fracture Testing of Metals. The results show that the bending introduced by the fixtures is strongly dependent on their relative rotational positions in respect to the loading rods which adapt them, to the tensile machine. For one set of tapered grips the highest bending was about 15%. Recommendations are made for improvement in the design of the tapered grips which should reduce the bending stresses substantially.

Structural Testing of a 6m Hypersonic Inflatable Aerodynamic Decelerator System

NASA Technical Reports Server (NTRS)

Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.

2015-01-01

NASA is developing low ballistic coefficient technologies to support the Nations long-term goal of landing humans on Mars. Current entry, decent, and landing technologies are not practical for this class of payloads due to geometric constraints dictated by current and future launch vehicle fairing limitations. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) are being developed to circumvent this limitation and are now considered a leading technology to enable landing of heavy payloads on Mars. At the beginning of 2014, a 6m diameter HIAD inflatable structure with an integrated flexible thermal protection system (TPS) was subjected to a static load test series to verify its structural performance under flight-relevant loads. The inflatable structure was constructed into a 60 degree sphere-cone configuration using nine inflatable torus segments composed of fiber-reinforced thin films. The inflatable tori were joined together using adhesives and high-strength textile woven structural straps. These straps help distribute the load throughout the inflatable structure. The 6m flexible TPS was constructed using multiple layers of high performance materials that are designed to protect the inflatable structure from heat loads that would be seen in flight during atmospheric entry. A custom test fixture was constructed to perform the static load test series. The fixture consisted of a round structural tub with enough height and width to allow for displacement of the HIAD test article as loads were applied. The bottom of the tub rim had an airtight seal with the floor. The rigid centerbody of the HIAD was mounted to a pedestal in the center of the structural tub. Using an impermeable membrane draped over the HIAD test article, an airtight seal was created with the top rim of the static load tub. This seal allowed partial vacuum to be pulled beneath the HIAD resulting in a uniform static pressure load applied to the outer surface. Using this technique, the test article was subjected to loads of up to 50,000lbs. During the test series an extensive amount of instrumentation was used to provide a rich data set, including deflected shape, structural strap loads, torus cord loads, inflation pressures, and applied static load. In this paper the 2014 6m HIAD static load test series will be discussed in detail, including the design of the 6m HIAD test article, the test setup, and test execution. Analysis results will be described supporting the conclusions that were drawn from the test series..

Elastic-Tether Suits for Artificial Gravity and Exercise

NASA Technical Reports Server (NTRS)

Torrance, Paul; Biesinger, Paul; Rybicki, Daniel D.

2005-01-01

Body suits harnessed to systems of elastic tethers have been proposed as means of approximating the effects of normal Earth gravitation on crewmembers of spacecraft in flight to help preserve the crewmembers physical fitness. The suits could also be used on Earth to increase effective gravitational loads for purposes of athletic training. The suit according to the proposal would include numerous small tether-attachment fixtures distributed over its outer surface so as to distribute the artificial gravitational force as nearly evenly as possible over the wearer s body. Elastic tethers would be connected between these fixtures and a single attachment fixture on a main elastic tether that would be anchored to a fixture on or under a floor. This fixture might include multiple pulleys to make the effective length of the main tether great enough that normal motions of the wearer cause no more than acceptably small variations in the total artificial gravitational force. Among the problems in designing the suit would be equalizing the load in the shoulder area and keeping tethers out of the way below the knees to prevent tripping. The solution would likely include running tethers through rings on the sides. Body suits with a weight or water ballast system are also proposed for very slight spinning space-station scenarios, in which cases the proposed body suits will easily be able to provide the equivalency of a 1-G or even greater load.

Vibration Testing of Electrical Cables to Quantify Loads at Tie-Down Locations

NASA Technical Reports Server (NTRS)

Dutson, Joseph D.

2013-01-01

The standard method for defining static equivalent structural load factors for components is based on Mile s equation. Unless test data is available, 5% critical damping is assumed for all components when calculating loads. Application of this method to electrical cable tie-down hardware often results in high loads, which often exceed the capability of typical tie-down options such as cable ties and P-clamps. Random vibration testing of electrical cables was used to better understand the factors that influence component loads: natural frequency, damping, and mass participation. An initial round of vibration testing successfully identified variables of interest, checked out the test fixture and instrumentation, and provided justification for removing some conservatism in the standard method. Additional testing is planned that will include a larger range of cable sizes for the most significant contributors to load as variables to further refine loads at cable tie-down points. Completed testing has provided justification to reduce loads at cable tie-downs by 45% with additional refinement based on measured cable natural frequencies.

Evaluation of a Highly Anticlastic Panel with Tow Overlaps

NASA Technical Reports Server (NTRS)

Wu, K. Chauncey; Gurdal, Zafer

2007-01-01

A rectangular, variable-stiffness panel with tow overlaps was manufactured using an advanced tow placement machine. The cured panel had large anticlastic imperfections, with measured amplitudes of over two times the average panel thickness. These imperfections were not due to the overall steered-fiber layup or the tow overlaps, but instead resulted from local asymmetries in the laminate that were caused by a manufacturing oversight. In the nominal panel layup, fiber angles vary linearly from 60 degrees on the panel axial centerline to 30 degrees on the parallel edges. A geometrically nonlinear analysis was performed with a -280 degree Fahrenheit thermal load to simulate the postcure cooldown to room temperature. The predicted geometric imperfections correlated well with the measured panel shape. Unique structural test fixtures were then developed which greatly reduced these imperfections, but they also caused prestresses in the panel. Surface imperfections measured after the panel was installed in the test fixtures were used with nonlinear finite element analyses to predict these fixturing-induced prestresses. These prestresses were also included in structural analyses of panel end compression to failure, and the analytical results compared well with test data when both geometric and material nonlinearities were included.

Titanium Aluminide Scramjet Inlet Flap Subelement Benchmark Tested

NASA Technical Reports Server (NTRS)

Krause, David L.; Draper, Susan L.

2005-01-01

A subelement-level ultimate strength test was completed successfully at the NASA Glenn Research Center (http://www.nasa.gov/glenn/) on a large gamma titanium aluminide (TiAl) inlet flap demonstration piece. The test subjected the part to prototypical stress conditions by using unique fixtures that allowed both loading and support points to be located remote to the part itself (see the photograph). The resulting configuration produced shear, moment, and the consequent stress topology proportional to the design point. The test was conducted at room temperature, a harsh condition for the material because of reduced available ductility. Still, the peak experimental load-carrying capability exceeded original predictions.

Measuring Fluctuating Pressure Levels and Vibration Response in a Jet Plume

NASA Technical Reports Server (NTRS)

Osterholt, Douglas J.; Knox, Douglas M.

2011-01-01

The characterization of loads due to solid rocket motor plume impingement allows for moreaccurate analyses of components subjected to such an environment. Typically, test verification of predicted loads due to these conditions is widely overlooked or unsuccessful. ATA Engineering, Inc., performed testing during a solid rocket motor firing to obtain acceleration and pressure responses in the hydrodynamic field surrounding the jet plume. The test environment necessitated a robust design to facilitate measurements being made in close proximity to the jet plume. This paper presents the process of designing a test fixture and an instrumentation package that could withstand the solid rocket plume environment and protect the required instrumentation.

Methodologies for Combined Loads Tests Using a Multi-Actuator Test Machine

NASA Technical Reports Server (NTRS)

Rouse, Marshall

2013-01-01

The NASA Langley COmbined Loads Test System (COLTS) Facility was designed to accommodate a range of fuselage structures and wing sections and subject them to both quasistatic and cyclic loading conditions. Structural tests have been conducted in COLTS that address structural integrity issues of metallic and fiber reinforced composite aerospace structures in support of NASA Programs (i.e. the Aircraft Structural Integrity (ASIP) Program, High-Speed-Research program and the Supersonic Project, NASA Engineering and Safety Center (NESC) Composite Crew Module Project, and the Environmentally Responsible Aviation Program),. This paper presents experimental results for curved panels subjected to mechanical and internal pressure loads using a D-box test fixture. Also, results are presented that describe use of a checkout beam for development of testing procedures for a combined mechanical and pressure loading test of a Multi-bay box. The Multi-bay box test will be used to experimentally verify the structural performance of the Multi-bay box in support of the Environmentally Responsible Aviation Project at NASA Langley.

Reactive Material Structures

DTIC Science & Technology

2014-03-31

dissimilar materials ( steel end fixtures and RMS). 2.6.4 Compression Tests To prevent the ends of the specimens from mushrooming during compression ...RMS cylinder. The compression test was modeled in ANSYS by applying a fixed displacement in the axial direction. The first ply to exceed the...four phases of loading: 1) a compressive acceleration during gun launch, 2) a tensile unloading on exit from the barrel , 3) a compressive decelera

Crash Testing of Helicopter Airframe Fittings

NASA Technical Reports Server (NTRS)

Clarke, Charles W.; Townsend, William; Boitnott, Richard

2004-01-01

As part of the Rotary Wing Structures Technology Demonstration (RWSTD) program, a surrogate RAH-66 seat attachment fitting was dynamically tested to assess its response to transient, crash impact loads. The dynamic response of this composite material fitting was compared to the performance of an identical fitting subjected to quasi-static loads of similar magnitude. Static and dynamic tests were conducted of both smaller bench level and larger full-scale test articles. At the bench level, the seat fitting was supported in a steel fixture, and in the full-scale tests, the fitting was integrated into a surrogate RAH-66 forward fuselage. Based upon the lessons learned, an improved method to design, analyze, and test similar composite material fittings is proposed.

Design and fabrication of graphite-epoxy bolted wing skin splice specimens

NASA Technical Reports Server (NTRS)

Johnson, R. W.; Mccarty, J. E.

1977-01-01

Graphite-epoxy bolted joint specimens were designed and fabricated. These specimens were to be representative of a side-of-body wing skin splice with a 20-year life expectancy in a commercial transport environment. Preliminary tests were performed to determine design values of bearing and net tension stresses. Based upon the information developed, a three-fastener-wide representative wing skin splice was designed for a load of 2627 KN/m (15,000 lbf/in.). One joint specimen was fabricated and tested at NASA. The wing skin splice failed at 106 percent of design ultimate load. This joint design achieved all static load objectives. Fabrication of six specimens, together with their loading fixtures, was completed, and the specimens were delivered to NASA-LRC.

Elevated-temperature application of the IITRI compression test fixture for graphite/polyimide filamentary composites

NASA Technical Reports Server (NTRS)

Raju, B. B.; Camarda, C. J.; Cooper, P. A.

1979-01-01

Seventy-nine graphite/polyimide compression specimens were tested to investigate experimentally the IITRI test method for determining compressive properties of composite materials at room and elevated temperatures (589 K (600 F)). Minor modifications were made to the standard IITRI fixture and a high degree of precision was maintained in specimen fabrication and load alignment. Specimens included four symmetric laminate orientations. Various widths were tested to evaluate the effect of width on measured modulus and strength. In most cases three specimens of each width were tested at room and elevated temperature and a polynomial regression analysis was used to reduce the data. Scatter of replicate tests and back-to-back strain variations were low, and no specimens failed by instability. Variation of specimen width had a negligible effect on the measured ultimate strengths and initial moduli of the specimens. Measured compressive strength and stiffness values were sufficiently high for the material to be considered a usable structural material at temperatures as high as 589 K (600 F).

Investigation of Hall Effect Thruster Channel Wall Erosion Mechanisms

DTIC Science & Technology

2016-08-02

pretest height and laser image, c, d) post - test height and laser image. On all the pre-roughened samples, a cell-pattern developed from the random...7.8: Pre and post - test sample microscopy: Fused silica sample SA6 (loaded), 20x, center of exposed surface, a, b) pretest height and laser image, c, d...stress on the surface features developed during plasma erosion. The experiment is also designed specifically to test the SRH. A test fixture is

Research on the design of fixture for motor vibration test

NASA Astrophysics Data System (ADS)

Shen, W. X.; Ma, W. S.; Zhang, L. W.

2018-03-01

The vibration reliability of the new energy automobile motor plays a very important role in driving safety, so it is very important to test the vibration durability of the motor. In the vibration test process, the fixture is very important, simulated road spectrum signal vibration can be transmitted without distortion to the motor through the fixture, fixture design directly affect the result of vibration endurance test. On the basis of new energy electric vehicle motor concrete structure, Two fixture design and fixture installation schemes for lateral cantilever type and base bearing type are put forward in this article, the selection of material, weighting process, middle alignment process and manufacturing process are summarized.The modal analysis and frequency response calculation of the fixture are carried out in this design, combine with influence caused by fixture height and structure profile on response frequency, the response frequency of each order of the fixture is calculated, then ultimately achieve the purpose of guiding the design.

Comparative Microstrain Study of Internal Hexagon and Plateau Design of Short Implants Under Vertical Loading.

PubMed

Nishioka, Renato Sussumu; Rodrigues, Vinicius Anéas; De Santis, Leandro Ruivo; Nishioka, Gabriela Nogueira De Melo; Santos, Vivian Mayumi Miyazaki; Souza, Francisley Ávila

2016-02-01

To quantify microstrain development during axial loading using strain gauge analysis for short implants, varying the type of fixture-abutment joint and thread design. An internal hexagon implant (4 × 8 mm) and a plateau design implant (4 × 8 mm) were embedded on the center of 10 polyurethane blocks with dimensions of 190 × 30 × 12 mm. The respective abutments were screwed onto the implants. Four strain gauges (SGs) were bonded onto the surface of each block, and 4 vertical SGs were bonded onto the side of each block. Axial load of 30 kgf was applied for 10 seconds in the center of each implant. The data were analyzed statistically by analysis of variance for repeated measures and Tukey test (P < 0.05). The interaction between implant and region factors have been statistically significant (P = 0.0259). Tukey test revealed a difference on plateau's horizontal region. The cervical region presented higher microstrain values, when compared with the medium and apical regions of the implants. Within the purpose of the study, the type of fixture-abutment joint is a relevant factor to affect the amount of stress/strain in bone simulation. The microstrain development was concentrated on the cervical region of the implant.

Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

2007-01-01

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semi-logarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

2007-01-01

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semilogarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

Effect of load introduction on graphite epoxy compression specimens

NASA Technical Reports Server (NTRS)

Reiss, R.; Yao, T. M.

1981-01-01

Compression testing of modern composite materials is affected by the manner in which the compressive load is introduced. Two such effects are investigated: (1) the constrained edge effect which prevents transverse expansion and is common to all compression testing in which the specimen is gripped in the fixture; and (2) nonuniform gripping which induces bending into the specimen. An analytical model capable of quantifying these foregoing effects was developed which is based upon the principle of minimum complementary energy. For pure compression, the stresses are approximated by Fourier series. For pure bending, the stresses are approximated by Legendre polynomials.

Immediate loading of implants in the aesthetic zone: comparison between two placement timings.

PubMed

Carini, Fabrizio; Longoni, Salvatore; Pisapia, Valeria; Francesconi, Manuel; Saggese, Vito; Porcaro, Gianluca

2014-01-01

Implant rehabilitation delivered in accordance with the traditional protocol has proven to be highly predictable and acceptable (1). Nevertheless, the application of immediate loading on post-extraction implants, especially for aesthetic zones, has now considerably increased (2). The aim of this work is to illustrate the immediate loading of implants placed in the aesthetic zone through tapered design fixtures with microgeometry of a high degree of porosity inserted at the same time or 4-8 weeks from dental avulsion (TSA® Advance, Phibo®). A total of 15 implant fixtures of which 8 at an interval of 4-8 weeks from extraction (type 2) and the remaining according to the immediate post-extraction technique (type 1) were positioned. All implants were prosthesized within 24 hours from the placement. Definitive crowns replaced provisional restorations after 20-24 weeks. After 4 and 12 months from implant insertion, the following parameters were assessed: X-ray image, pain, mobility or suppuration, soft tissue condition and aesthetic appearance. Percentage of osseointegration was 93.75%, and 53.5% of the osseointegrated fixtures was type 2. No statistically significant difference between the mean ISQ values for implants of type 1 and 2 both in the post-operative period and after 12 months was evident, indicating that the timing of insertion did not affect the achievement of stability for the implant fixtures tested in our study. Immediate post-extraction implants showed a greater propensity for gingival recession and a peri-implant radiolucency greater than those placed at an interval of 4-8 weeks. The values obtained for the PES/WES and the subjective evaluation of the analyzed sample showed the considerable aesthetic value and the high level of satisfaction guaranteed by the implant technique illustrated. Although well-designed, high quality, randomized clinical trials are still needed as well as the requirement to establish a common, complete, and reproducible index for the evaluation of aesthetic outcome, immediate/early placement and loading of a single TSA® Advance, Phibo® may be considered a valuable and predictable option in terms of implant success as well as hard and soft tissue stability.

A comparative study of gold UCLA-type and CAD/CAM titanium implant abutments

PubMed Central

Park, Ji-Man; Lee, Jai-Bong; Heo, Seong-Joo

2014-01-01

PURPOSE The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments. MATERIALS AND METHODS An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of ±0.1 µm at 50 points. RESULTS Initial detorque values of milled abutment were significantly higher than those of cast abutment (P<.05). Detorque values after one million dynamic cyclic loadings were not significantly different (P>.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (P<.05). There was no significant difference of gap dimension between the milled abutment group and the cast abutment group after cyclic loading. CONCLUSION In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment. PMID:24605206

Graphite Composite Panel Polishing Fixture

NASA Technical Reports Server (NTRS)

Hagopian, John; Strojny, Carl; Budinoff, Jason

2011-01-01

The use of high-strength, lightweight composites for the fixture is the novel feature of this innovation. The main advantage is the light weight and high stiffness-to-mass ratio relative to aluminum. Meter-class optics require support during the grinding/polishing process with large tools. The use of aluminum as a polishing fixture is standard, with pitch providing a compliant layer to allow support without deformation. Unfortunately, with meter-scale optics, a meter-scale fixture weighs over 120 lb (.55 kg) and may distort the optics being fabricated by loading the mirror and/or tool used in fabrication. The use of composite structures that are lightweight yet stiff allows standard techniques to be used while providing for a decrease in fixture weight by almost 70 percent. Mounts classically used to support large mirrors during fabrication are especially heavy and difficult to handle. The mount must be especially stiff to avoid deformation during the optical fabrication process, where a very large and heavy lap often can distort the mount and optic being fabricated. If the optic is placed on top of the lapping tool, the weight of the optic and the fixture can distort the lap. Fixtures to support the mirror during fabrication are often very large plates of aluminum, often 2 in. (.5 cm) or more in thickness and weight upwards of 150 lb (68 kg). With the addition of a backing material such as pitch and the mirror itself, the assembly can often weigh over 250 lb (.113 kg) for a meter-class optic. This innovation is the use of a lightweight graphite panel with an aluminum honeycomb core for use as the polishing fixture. These materials have been used in the aerospace industry as structural members due to their light weight and high stiffness. The grinding polishing fixture consists of the graphite composite panel, fittings, and fixtures to allow interface to the polishing machine, and introduction of pitch buttons to support the optic under fabrication. In its operation, the grinding polishing fixture acts as a reaction structure to the polishing tool. It must be stiff enough to avoid imparting a distorted shape to the optic under fabrication and light enough to avoid self-deflection. The fixture must also withstand significant tangential loads from the polishing machine during operations.

EIGHTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W. L.

2013-09-03

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23more » GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 61 - 85 months, which is still bounding to O-ring temperatures during storage in KArea Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leaktight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 41 - 45 months. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

Analysis of stiffness reduction in varying curvature ankle foot orthoses.

PubMed

Braund, Matt; Kroontje, David; Brooks, James; Self, Brian; Aaron, Gregory; Bearden, Keith

2005-01-01

Ankle foot orthoses (AFO) are often used for patients who cannot generate a strong enough extension moment at the knee to allow functional gait. Orthotists often cut out portions of the AFO around the malleoli in order to improve comfort. There has been some question as to how this affects the stress distribution around the orthosis, the fatigue performance of the device, and the AFOs stiffness. To examine this, three orthoses were constructed with differing curvatures cut out of the malleolar regions. Photoelastic coatings were placed on the most stiff and least stiff orthoses, and the stress distributions while wearing the device were examined. A fixture was created to test the orthosis, and the stress distribution while loaded in the fixture closely matched the distribution with actual wear. These orthoses were then tested in fatigue for 500,000 cycles at 5 Hz in displacement control. Initial displacements were set to provide maximum loads of 45 lbs. The displacement settings for the stiffest orthosis were 0.4 to 0.6 inches of deflection; the load decreased from 44 lbs to 28 lbs after the final cycle. The least stiff displacement varied from 1.3 to 1.5 inches, and the load value changed from 46 lbs to 35 lbs. The data will be useful in guiding orthotists in building AFOs, particularly when shaving portions of the AFO for comfort. Excessive shaving may seriously degrade the performance of the device, especially after longer life cycles.

Load deflection characteristics of inflated structures

NASA Technical Reports Server (NTRS)

Baumgarten, J. R.

1983-01-01

A single, closed form relationship to relate load to the deformed dimensions of the horizontal torus was developed. Wall elasticity was included in the analysis, and special care was taken to predict the final footprint area of the loaded structure. The test fixture utilized is shown. The tori used for the bulk of the testing were rubber inner tubes for a 32 and 160 pneumatic tire. The inner tube being tested was plumbed, to a mercury-filled manometer, which had a 50 inch measurement capacity, by use of a special adapter. The adapter fit over the valve stem and allowed air to be added from a shop-air source and to be bled through the standard valve mechanism. In this fashion, tests requiring the maintenance of a constant indication of air pressure could be run with little difficulty.

Experimental Aerodynamic Facilities of the Aerodynamics Research and Concepts Assistance Section

DTIC Science & Technology

1983-02-01

experimental data desired. Internal strain gage balances covering a range of sizes and load capabilities are available for static force and moment tests...tunnel. Both sting and side wall model mounts are available which can be adapted to a variety of internal strain gage balance systems for force and...model components or liquids in the test section. A selection of internal and external strain gage balances and associated mounting fixtures are

Manufacturing Systems Demonstration: Bimetallic Friction STIR Joining of AA6061 and High Hardness Steel

DTIC Science & Technology

2013-05-31

fusion welding and virtually eliminates the material porosity inherent with liquid alloy processes. Also because less heat is input to the material...Fe intermetallic present. Mechanical load testing determined that the bimetallic FSP joint was stronger than similar AA6061-to-AA6061 fusion- welded and...5 b) Weld Coupon Fixture ........................................................................................ 5 2. Friction Stir Tools

A study of facilities and fixtures for testing of a high speed civil transport wing component

NASA Technical Reports Server (NTRS)

Cerro, J. A.; Vause, R. F.; Bowman, L. M.; Jensen, J. K.; Martin, C. J., Jr.; Stockwell, A. E.; Waters, W. A., Jr.

1996-01-01

A study was performed to determine the feasibility of testing a large-scale High Speed Civil Transport wing component in the Structures and Materials Testing Laboratory in Building 1148 at NASA Langley Research Center. The report includes a survey of the electrical and hydraulic resources and identifies the backing structure and floor hard points which would be available for reacting the test loads. The backing structure analysis uses a new finite element model of the floor and backstop support system in the Structures Laboratory. Information on the data acquisition system and the thermal power requirements is also presented. The study identified the hardware that would be required to test a typical component, including the number and arrangement of hydraulic actuators required to simulate expected flight loads. Load introduction and reaction structure concepts were analyzed to investigate the effects of experimentally induced boundary conditions.

46 CFR 154.406 - Design loads for cargo tanks and fixtures: General.

Code of Federal Regulations, 2010 CFR

2010-10-01

... motion of the vessel. (4) Transient or stationary thermal loads if the design temperature is colder that..., cargo weight, and corresponding support reaction. (8) Insulation weight. (9) Loads of a pipe tower and...

46 CFR 154.406 - Design loads for cargo tanks and fixtures: General.

Code of Federal Regulations, 2011 CFR

2011-10-01

... motion of the vessel. (4) Transient or stationary thermal loads if the design temperature is colder that..., cargo weight, and corresponding support reaction. (8) Insulation weight. (9) Loads of a pipe tower and...

Shear-Panel Test Fixture Eliminates Corner Stresses

NASA Technical Reports Server (NTRS)

Kiss, J. J.; Farley, G. L.; Baker, D. J.

1984-01-01

New design eliminates corner stresses while maintaining uniform stress across panel. Shear panel test fixture includes eight frames and eight corner pins. Fixture assembled in two halves with shear panel sandwiched in between. Results generated from this fixture will result in good data base for design of efficient aircraft structures and other applications.

Overview of the 2nd Gen 3.7m HIAD Static Load Test

NASA Technical Reports Server (NTRS)

Swanson, G. T.; Kazemba, C. D.; Johnson, R. K.; Hughes, S. J.; Calomino, A. M.; Cheatwood, F. M.; Cassell, A. M.; Anderson, P.; Lowery, A.

2015-01-01

To support NASAs long term goal of landing humans on Mars, technologies which enable the landing of heavy payloads are being developed. Current entry, decent, and landing technologies are not practical for human class payloads due to geometric constraints dictated by current launch vehicle fairing limitations. Therefore, past and present technologies are now being explored to provide a mass and volume efficient solution to atmospheric entry, including Hypersonic Inflatable Aerodynamic Decelerators (HIADs). In October of 2014, a 3.7m HIAD inflatable structure with an integrated flexible thermal protection sys-tem (F-TPS) was subjected to a static load test series to verify the designs structural performance. The 3.7m HIAD structure was constructed in a 70 deg sphere-cone stacked-toroid configuration using eight inflatable tori, which were joined together using adhesives and high strength textile webbing to help distribute the loads throughout the inflatable structure. The inflatable structure was fabricated using 2nd generation structural materials that permit an increase in use temperature to 400 C+ as compared to the 250 C limitation of the 1st generation materials. In addition to the temperature benefit, these materials also offer a 40 reduction in structure mass. The 3.7m F-TPS was fabricated using high performance materials to protect the inflatable structure from heat loads that would be seen during atmospheric entry. The F-TPS was constructed of 2nd generation TPS materials increasing its heating capability from 35W sq cm to over 100W sq cm. This test article is the first stacked-torus HIAD to be fabricated and tested with a 70 deg sphere-cone. All previous stacked-torus HIADs have employed a 60o sphere-cone. To perform the static load test series, a custom test fixture was constructed. The fixture consisted of a structural tub rim with enough height to allow for dis-placement of the inflatable structure as loads were applied. The tub rim was attached to the floor to provide an airtight seal. The center body of the inflatable structure was attached to a pedestal mount as seen in Figure 1. Using an impermeable membrane seal draped over the test article, partial vacuum was pulled beneath the HIAD, resulting in a uniform static pressure load applied to the outer surface. During the test series an extensive amount of instrumentation was used to characterize deformed shape, shoulder deflection, strap loads, and cord loads as a function of structural configuration and applied static load. In this overview, the 3.7m HIAD static load test series will be discussed in detail, including the 3.7m HIAD inflatable structure and flexible TPS design, test setup and execution, and finally results and conclusions from the test series.

Mixed-Mode Bending Method for Delamination Testing

NASA Technical Reports Server (NTRS)

Reeder, James R.; Crews, John R., Jr.

1990-01-01

A mixed mode delamination test procedure was developed combining double cantilever beam (DCB) mode I loading and end-notch fixture (ENF) mode II loading on a split unidirectional laminate. By loading with a lever, a single applied load simultaneously produces mode I and mode II bending loads on the specimen. This mixed-mode bending (MMB) test was analyzed using both finite-element procedures and beam theory to calculate the mode I and mode II components of strain-energy release rate G(sub I) and G(sub II), respectively. A wide range of G(sub I)/G(sub II) ratios can be produced by varying the load position on the lever. As the delamination extended, the G(sub I)/G(sub II) ratios varied by less than 5%. Beam theory equations agreed closely with the finite-element results and provide a basis for selection of G(sub I)/G(sub II) test ratios and a basis for computing the mode I and mode II components of measured delamination toughness. The MMB test was demonstrated using AS4/PEEK (APC2) unidirectional laminates. The MMB test introduced in this paper is rather simple and is believed to offer several advantages over most current mixed-mode test.

Contact resistance evolution of highly cycled, lightly loaded micro-contacts

NASA Astrophysics Data System (ADS)

Stilson, Christopher; Coutu, Ronald

2014-03-01

Reliable microelectromechanical systems (MEMS) switches are critical for developing high performance radio frequency circuits like phase shifters. Engineers have attempted to improve reliability and lifecycle performance using novel contact metals, unique mechanical designs and packaging. Various test fixtures including: MEMS devices, atomic force microscopes (AFM) and nanoindentors have been used to collect resistance and contact force data. AFM and nanoindentor test fixtures allow direct contact force measurements but are severely limited by low resonance sensors, and therefore low data collection rates. This paper reports the contact resistance evolution results and fabrication of thin film, sputtered and evaporated gold, micro-contacts dynamically tested up to 3kHz. The upper contact support structure consists of a gold surface micromachined, fix-fix beam designed with sufficient restoring force to overcome adhesion. The hemisphere-upper and planar-lower contacts are mated with a calibrated, external load resulting in approximately 100μN of contact force and are cycled in excess of 106 times or until failure. Contact resistance is measured, in-situ, using a cross-bar configuration and the entire apparatus is isolated from external vibration and housed in an enclosure to minimize contamination due to ambient environment. Additionally, contact cycling and data collection are automated using a computer and LabVIEW. Results include contact resistance measurements of 6 and 8 μm radius contact bumps and lifetime testing up to 323.6 million cycles.

Constitutive Modeling of a Glass Fiber-Reinforced PTFE Gasketed-Joint Under a Re-torque

NASA Astrophysics Data System (ADS)

Williams, James; Gordon, Ali P.

Joints gasketed with viscoelastic seals often receive an application of a secondary torque, i.e., retorque, in order to ensure joint tightness and proper sealing. The motivation of this study is to characterize and analytically model the load and deflection re-torque response of a single 25% glass-fiber reinforced polytetrafluorethylene (PTFE) gasket-bolted joint with serrated flange detail. The Burger-type viscoelastic modeling constants of the material are obtained through isolating the gasket from the bolt by performing a gasket creep test via a MTS electromechanical test frame. The re-load creep response is also investigated by re-loading the gasket after a period of initial creep to observe the response. The modeling constants obtained from the creep tests are used with a Burger-type viscoelastic model to predict the re-torque response of a single bolt-gasket test fixture in order to validate the ability of the model to simulate the re-torque response under various loading conditions and flange detail.

SEVENTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2012-08-30

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23more » GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 54-72 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 30 - 36 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the O-rings displayed a compression set ranging from 51 – 96%. This is greater than seen to date for any packages inspected during KAC field surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350 – 400 ºF). However, at 300 ºF, the room temperature leak test failures to date experienced longer aging times than predicted by the CSRbased model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 ºF will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining PCV O-ring fixtures.« less

NINTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2014-08-06

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperatures. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determinemore » if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The earliest 300 °F GLT O-ring fixture failure was observed at 34 months. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 72 - 96 months, which bounds O-ring temperatures anticipated during storage in K-Area Complex (KAC). Based on expectations that the 200 ºF fixtures will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures, thus providing additional time to failure data. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 54 - 57 months. No additional O-ring failures have been observed since the last interim report was issued. Aging and periodic leak testing will continue for the remaining PCV fixtures. Additional irradiation of several fixtures is recommended to maintain a balance between thermal and radiation exposures similar to that experienced in storage, and to show the degree of consistency of radiation response between GLT and GLT-S O-rings.« less

SIXTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2011-08-31

A series of experiments to monitor the aging performance of Viton{reg_sign} GLT O-rings used in the Model 9975 package has been ongoing for seven years at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues formore » 33 GLT O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 F and higher temperatures, and in 7 fixtures aging at 300 F. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 41-60 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 F will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging within the past year at an intermediate temperature of 270 F, with hopes that they may leak before the 200 F fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 F. No failures have yet been observed in GLT-S O-ring fixtures aging at 200-300 F for up to 26 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the Orings displayed a compression set ranging from 51-96%. This is greater than seen to date for packages inspected during KAC field surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350-400 F). However, at 300 F, the room temperature leak test failures to date experienced longer aging times than predicted by the CSR-based model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 F will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining fixtures.« less

Advanced Joining of Aerospace Metallic Materials.

DTIC Science & Technology

1986-07-01

uniaxial tensile test with varying temperature and cyclic loading. This simple test problem excercises maray aspects of the phenomena. suOn- ,Ual Yield...6vidence Ia seconde configuration apparait plus n~ faste . 5.3. Ents-e-igne-men-t-s s-u r a dyna-mique de. bain-s de fu-sion A lusage il svest r~vle que la...scanning system for fast and exact alignment of the EB-qun is used. In a fixture the cleaned detail parts are positioned exactly and clamped for welding. At

Test and Analysis of Composite Hat Stringer Pull-off Test Specimens

NASA Technical Reports Server (NTRS)

Li, Jian; OBrien, T. Kevin; Rousseau, Carl Q.

1996-01-01

Hat stringer pull-off tests were performed to evaluate the delamination failure mechanisms in the flange region for a rod-reinforced hat stringer section. A special test fixture was used to pull the hat off the stringer while reacting the pull-off load through roller supports at both stringer flanges. Microscopic examinations of the failed specimens revealed that failure occurred at the ply termination in the flange area where the flange of the stiffener is built up by adding 45/-45 tape plies on the top surface. Test results indicated that the as-manufactured microstructure in the flange region has a strong influence on the delamination initiation and the associated pull-off loads. Finite element models were created for each specimen with a detailed mesh based on micrographs of the critical location. A fracture mechanics approach and a mixed mode delamination criterion were used to predict the onset of delamination and the pull-off load. By modeling the critical local details of each specimen from micrographs, the model was able to accurately predict the hat stringer pull-off loads and replicate the variability in the test results.

F-15B/Flight Test Fixture 2: A Test Bed for Flight Research

NASA Technical Reports Server (NTRS)

Richwine, David M.

1996-01-01

NASA Dryden Flight Research Center has developed a second-generation flight test fixture for use as a generic test bed for aerodynamic and fluid mechanics research. The Flight Test Fixture 2 (FTF-2) is a low-aspect-ratio vertical fin-like shape that is mounted on the centerline of the F-I5B lower fuselage. The fixture is designed for flight research at Mach numbers to a maximum of 2.0. The FTF-2 is a composite structure with a modular configuration and removable components for functional flexibility. This report documents the flow environment of the fixture, such as surface pressure distributions and boundary-layer profiles, throughout a matrix of conditions within the F-15B/FTF-2 flight envelope. Environmental conditions within the fixture are presented to assist in the design and testing of future avionics and instrumentation. The intent of this document is to serve as a user's guide and assist in the development of future flight experiments that use the FTF-2 as a test bed. Additional information enclosed in the appendices has been included to assist with more detailed analyses, if required.

FY2017 status report: Model 9975 O-ring fixture long-term leak performance

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

Daugherty, W. L.

A series of experiments to monitor the aging performance of Viton® GLT and GLT-S O-rings used in the Model 9975 shipping package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups with GLT O-rings were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially andmore » have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, a smaller test matrix with fourteen additional tests was initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. Leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The 300 °F GLT O-ring fixtures failed after 2.8 to 5.7 years at temperature. The remaining GLT O-ring fixtures aging at 300 ºF were retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 9 to 10.5 years, or in GLT O-ring fixtures aging at 270 ºF for 5.7 years. These aging temperatures bound O-ring temperatures anticipated during normal storage in K-Area Complex (KAC). Leak test failures have been experienced in all of the GLT-S O-ring fixtures aging at 300 ºF and above. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 and 250 ºF for 6.9 to 7.5 years. Data from the O-ring fixtures are generally consistent with results from compression stress relaxation testing, and provide confidence in the predictive models based on those results. However, uncertainty still exists in extrapolating these elevated temperature results to the lower temperatures of interest for normal storage in KAC. Measurement of compression set in O-rings removed from failed fixtures, compared to that from KAC surveillance O-rings, indicates margin remains for O-rings still in service. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

Simulating flight boundary conditions for orbiter payload modal survey

NASA Technical Reports Server (NTRS)

Chung, Y. T.; Sernaker, M. L.; Peebles, J. H.

1993-01-01

An approach to simulate the characteristics of the payload/orbiter interfaces for the payload modal survey was developed. The flexure designed for this approach is required to provide adequate stiffness separation in the free and constrained interface degrees of freedom to closely resemble the flight boundary condition. Payloads will behave linearly and demonstrate similar modal effective mass distribution and load path as the flight if the flexure fixture is used for the payload modal survey. The potential non-linearities caused by the trunnion slippage during the conventional fixed base modal survey may be eliminated. Consequently, the effort to correlate the test and analysis models can be significantly reduced. An example is given to illustrate the selection and the sensitivity of the flexure stiffness. The advantages of using flexure fixtures for the modal survey and for the analytical model verification are also demonstrated.

Warrior Injury Assessment Manikin (WIAMan) Lumbar Spine Model Validation: Development, Testing, and Analysis of Physical and Computational Models of the WIAMan Lumbar Spine Materials Demonstrator

DTIC Science & Technology

2016-08-01

load. The 1 and 10 s-1 rate tests were run on a hydraulic high-rate Instron MTS (8821S), placed in a custom- designed tension fixture (Fig. 8...lateral compression prior to shear testing . The sides of the coupon rest on blocks at the bottom of the vice jaw to allow for travel of the center post ...mode of failure based on the lap shear testing . However, since the pretest spine survived all hits at the BRC speeds, it was decided to proceed with

A method for accounting for test fixture compliance when estimating proximal femur stiffness.

PubMed

Rossman, Timothy; Dragomir-Daescu, Dan

2016-09-06

Fracture testing of cadaveric femora to obtain strength and stiffness information is an active area of research in developing tools for diagnostic prediction of bone strength. These measurements are often used in the estimation and validation of companion finite element models constructed from the femora CT scan data, therefore, the accuracy of the data is of paramount importance. However, experimental stiffness calculated from force-displacement data has largely been ignored by most researchers due to inherent error in the differential displacement measurement obtained when not accounting for testing apparatus compliance. However, having such information is necessary for validation of computational models. Even in the few cases when fixture compliance was considered the measurements showed large lab-to-lab variation due to lack of standardization in fixture design. We examined the compliance of our in-house designed cadaveric femur test fixture to determine the errors we could expect when calculating stiffness from the collected experimental force-displacement data and determined the stiffness of the test fixture to be more than 10 times the stiffness of the stiffest femur in a sample of 44 femora. When correcting the apparent femur stiffness derived from the original data, we found that the largest stiffness was underestimated by about 10%. The study confirmed that considering test fixture compliance is a necessary step in improving the accuracy of fracture test data for characterizing femur stiffness, and highlighted the need for test fixture design standardization for proximal femur fracture testing. Copyright © 2016 Elsevier Ltd. All rights reserved.

Blast protection of infrastructure using advanced composites

NASA Astrophysics Data System (ADS)

Brodsky, Evan

This research was a systematic investigation detailing the energy absorption mechanisms of an E-glass web core composite sandwich panel subjected to an impulse loading applied orthogonal to the facesheet. Key roles of the fiberglass and polyisocyanurate foam material were identified, characterized, and analyzed. A quasi-static test fixture was used to compressively load a unit cell web core specimen machined from the sandwich panel. The web and foam both exhibited non-linear stress-strain responses during axial compressive loading. Through several analyses, the composite web situated in the web core had failed in axial compression. Optimization studies were performed on the sandwich panel unit cell in order to maximize the energy absorption capabilities of the web core. Ultimately, a sandwich panel was designed to optimize the energy dissipation subjected to through-the-thickness compressive loading.

Analysis of a Hybrid Wing Body Center Section Test Article

NASA Technical Reports Server (NTRS)

Wu, Hsi-Yung T.; Shaw, Peter; Przekop, Adam

2013-01-01

The hybrid wing body center section test article is an all-composite structure made of crown, floor, keel, bulkhead, and rib panels utilizing the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) design concept. The primary goal of this test article is to prove that PRSEUS components are capable of carrying combined loads that are representative of a hybrid wing body pressure cabin design regime. This paper summarizes the analytical approach, analysis results, and failure predictions of the test article. A global finite element model of composite panels, metallic fittings, mechanical fasteners, and the Combined Loads Test System (COLTS) test fixture was used to conduct linear structural strength and stability analyses to validate the specimen under the most critical combination of bending and pressure loading conditions found in the hybrid wing body pressure cabin. Local detail analyses were also performed at locations with high stress concentrations, at Tee-cap noodle interfaces with surrounding laminates, and at fastener locations with high bearing/bypass loads. Failure predictions for different composite and metallic failure modes were made, and nonlinear analyses were also performed to study the structural response of the test article under combined bending and pressure loading. This large-scale specimen test will be conducted at the COLTS facility at the NASA Langley Research Center.

Optical alignment of the JWST ISIM to the OTE simulator (OSIM): current concept and design studies

NASA Astrophysics Data System (ADS)

Frey, Bradley J.; Davila, Pamela S.; Hagopian, John G.; Marsh, James M.; Ohl, Raymond G.; Wilson, Mark E.; Young, Philip J.

2007-09-01

The James Webb Space Telescope's (JWST) Integrated Science Instrument Module (ISIM) contains the observatory's four science instruments and their support subsystems. During alignment and test of the integrated ISIM at NASA's Goddard Space Flight Center (GSFC), the Optical telescope element SIMulator (OSIM) will be used to optically stimulate the science instruments to verify their operation and performance. In this paper we present the design of two cryogenic alignment fixtures that will be used to align the OSIM to the ISIM during testing at GSFC. These fixtures, the Master Alignment Target Fixture (MATF) and the ISIM Alignment Target Fixture (IATF), will provide continuous, six degree of freedom feedback to OSIM during initial ambient alignment as well as during cryogenic vacuum testing. These fixtures will allow us to position the OSIM and detect OSIM-ISIM absolute alignment to better than 180 microns in translation and 540 micro-radians in rotation. We will provide a brief overview of the OSIM system and we will also discuss the relevance of these fixtures in the context of the overall ISIM alignment and test plan.

The Shock and Vibration Bulletin. Part 4. Vibration Testing, Instrumentation, Loads and Environments, Tracked Vehicles

DTIC Science & Technology

1978-09-01

self with a nonlinear (thermocouple) function, the limits X os nu 2O being: x Enables Temperature Controller to command heat 0 Code Temnperature ___6...34 Shock and Vi- bration Bulletin 42, 1970. (2) R.T. Fandrich, " Self -Tuning Re- • sonant Fixtures", 47th Shock andVibration Symposium, October 1976. . " (3...is given in Fig. 4. timTit for "ysem From the shape of some of these it is apparent linear respose that in some tests dampino ratios of the order 0 of

Extended Life PZT Stack Test Fixture

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, S.; Bao, X.; Aldrich, J.; Bar-Cohen, Y.; Jones, C.

2009-01-01

Piezoelectric stacks are being sought to be used as actuators for precision positioning and deployment of mechanisms in future planetary missions. Beside the requirement for very high operation reliability, these actuators are required for operation at space environments that are considered harsh compared to normal terrestrial conditions.These environmental conditions include low and high temperatures and vacuum or high pressure. Additionally, the stacks are subjected to high stress and in some applications need to operate with a very long lifetime durability.Many of these requirements are beyond the current industry design margins for nominal terrestrial applications. In order to investigate some of the properties that will indicate the durability of such actuators and their limitations we have developed a new type of test fixture that can be easily integrated in various test chambers for simulating environmental conditions, can provide access for multiple measurements while being exposed to adjustable stress levels. We designed and built two test fixtures and these fixtures were made to be adjustable for testing stacks with different dimensions and can be easily used in small or large numbers. The properties that were measured using these fixtures include impedance, capacitance, dielectric loss factor, leakage current, displacement, breakdown voltage, and lifetime performance. The fixtures characteristics and the test capabilities are presented in this paper.

Periodontitis and periimplantitis: one and the same?

PubMed

Meffert, R M

1993-12-01

Research shows that the same anaerobic, gram-negative pathogens are present in the periodontal and implant pocket or crevice. The implants in a partially edentulous case are probably more at risk due to the bacteria being more pathogenic and a seeding mechanism from the tooth pocket to the implant crevice. In the face of a normal microbial flora, retrograde periimplantitis or radiographic bone loss without gingival changes may be due to trauma because of overloading, loading too soon, and/or loading in a lateral direction. Finally, the combination of an infective process (periimplantitis) and noninfective or traumatic process (retrograde periimplantitis) will result in rapid osseous destruction and, possibly, loss of the implant fixture(s).

Thermal Vacuum Testing of Swift XRT Ethane Heat Pipes

NASA Technical Reports Server (NTRS)

Kobel, Mark; Ku, Jentung

2003-01-01

This paper presents the results obtained from a recent ethane heat pipe program. Three identical ethane heat pipes were tested individually, and then two selected heat pipes were tested collectively in their system configuration. Heat transport, thermal conductance, and non-condensable gas tests were performed on each heat pipe. To gain insight into the reflux operation as seen at spacecraft level ground testing, the test fixture was oriented in a vertical configuration. The system level test included a computer-controlled heater designed to emulate the heat load generated at the thermoelectric cooler interface. The system performance was successfully characterized for a wide range of environmental conditions while staying within the operating limits.

Immediate functional loading of single implants: a multicenter study with 4 years of follow-up

PubMed Central

Raes, Filiep; Eccellente, Tammaro; Lenzi, Carolina; Ortolani, Michele; Luongo, Giuseppe; Mangano, Carlo; Mangano, Francesco

2018-01-01

Background. In the current scientific literature there are only few studies on the immediate functional loading of single implants. The aim of the present present study was to evaluate the 4-year survival rate, complication rate and peri-implant marginal bone loss (PIMBL) of immediately loaded single implants inserted in healed ridges and fresh post-extraction sites. Methods. Six centers were involved in this prospective study. The surgical and prosthetic protocol was defined in detail, before the start of recruiting patients. Recruitment of patients and performance of surgeries took place between February 2012 and February 2013. Criteria for inclusion were single-tooth gaps in healed ridges and fresh post-extraction sockets. All the fixtures (Anyridge®, Megagen Corporation, Gyeongbuk, South Korea) were functionally loaded immediately after insertion and followed for a period of 4 years. Outcome measures were implant survival, complications and PIMBL. Results. Forty-six patients (18‒73 years of age) were selected. In total, 57 fixtures were placed (10 in fresh post-extraction sockets). After 4 years of functional loading, only one fixture was lost; therefore, high survival rates (97.6% patient-based; 98.1% implant-based) were reported. In addition, a limited incidence of biologic (4.8% patient-based; 3.8% implant-based) and prosthetic (9.7% patient-based; 7.6% implant-based) complications was reported. The overall 4-year PIMBL amounted to 0.38±0.21 mm (healed ridges: 0.4±0.21 mm; fresh post-extraction sockets: 0.33±0.20 mm). Conclusion. Loading single implants immediately seems to be a highly successful treatment modality. However, long-term data are needed to confirm these positive outcomes. PMID:29732018

A low cost method of testing compression-after-impact strength of composite laminates

NASA Technical Reports Server (NTRS)

Nettles, Alan T.

1991-01-01

A method was devised to test the compression strength of composite laminate specimens that are much thinner and wider than other tests require. The specimen can be up to 7.62 cm (3 in) wide and as thin as 1.02 mm (.04 in). The best features of the Illinois Institute of Technology Research Institute (IITRI) fixture are combined with an antibuckling jig developed and used at the University of Dayton Research Institute to obtain a method of compression testing thin, wide test coupons on any 20 kip (or larger) loading frame. Up to 83 pct. less composite material is needed for the test coupons compared to the most commonly used compression-after-impact (CAI) tests, which calls for 48 ply thick (approx. 6.12 mm) test coupons. Another advantage of the new method is that composite coupons of the exact lay-up and thickness of production parts can be tested for CAI strength, thus yielding more meaningful results. This new method was used to compression test 8 and 16 ply laminates of T300/934 carbon/epoxy. These results were compared to those obtained using ASTM standard D 3410-87 (Celanese compression test). CAI testing was performed on IM6/3501-6, IM7/SP500 and IM7/F3900. The new test method and associated fixture work well and is a valuable asset to MSFC's damage tolerance program.

A Hot Dynamic Seal Rig for Measuring Hypersonic Engine Seal Durability and Flow Performance

NASA Technical Reports Server (NTRS)

Miller, Jeffrey H.; Steinetz, Bruce M.; Sirocky, Paul J.; Kren, Lawrence A.

1993-01-01

A test fixture for measuring the dynamic performance of candidate high-temperature engine seal concepts was installed at NASA Lewis Research Center. The test fixture was designed to evaluate seal concepts under development for advanced hypersonic engines, such as those being considered for the National Aerospace Plane (NASP). The fixture can measure dynamic seal leakage performance from room temperature up to 840 C (1550 F) and air pressure differentials up to 690 kPa (100 psi). Performance of the seals can be measured while sealing against flat or distorted walls. In the fixture two seals are preloaded against the sides of a 30 cm (1 ft) long saber that slides transverse to the axis of the seals, simulating the scrubbing motion anticipated in these engines. The capabilities of this test fixture along with preliminary data showing the dependence of seal leakage performance on high temperature cycling are addressed.

Hot dynamic test rig for measuring hypersonic engine seal flow and durability

NASA Technical Reports Server (NTRS)

Miller, Jeffrey H.; Steinetz, Bruce M.; Sirocky, Paul J.; Kren, Lawrence A.

1994-01-01

A test fixture for measuring the dynamic performance of candidate high-temperature engine seal concepts was developed. The test fixture was developed to evaluate seal concepts under development for advanced hypersonic engines, such as those being considered for the National Aerospace Plane (NASP). The fixture can measure dynamic seal leakage performance from room temperature up to 840 C and air pressure differentials of to 0.7 MPa. Performance of the seals can be measured while sealing against flat or engine-simulated distorted walls. In the fixture, two seals are preloaded against the sides of a 0.3 m long saber that slides transverse to the axis of the seals, simulating the scrubbing motion anticipated in these engines. The capabilities of this text fixture along with preliminary data showing the dependence of seal leakage performance on high temperature cycling are covered.

A hot dynamic seal rig for measuring hypersonic engine seal durability and flow performance

NASA Technical Reports Server (NTRS)

Miller, Jeffrey H.; Steinetz, Bruce M.; Sirocky, Paul J.; Kren, Lawrence A.

1993-01-01

A test fixture for measuring the dynamic performance of candidate high-temperature engine seal concepts has been installed at NASA Lewis Research Center. The test fixture has been designed to evaluate seal concepts under development for advanced hypersonic engines, such as those being considered for the National Aerospace Plane (NASP). The fixture can measure dynamic seal leakage performance from room temperature up to 840 C (1550 F) and air pressure differentials up to 690 kPa (100 psi). Performance of the seals can be measured while sealing against flat or distorted walls. In the fixture two seals are preloaded against the sides of a 30 cm (1 ft) long saber that slides transverse to the axis of the seals, simulating the scrubbing motion anticipated in these engines. This report covers the capabilities of this test fixture along with preliminary data showing the dependence of seal leakage performance on high temperature cycling.

Multiple direction vibration fixture

DOEpatents

Cericola, Fred; Doggett, James W.; Ernest, Terry L.; Priddy, Tommy G.

1991-01-01

An apparatus for simulating a rocket launch environment on a test item undergoing centrifuge testing by subjecting the item simultaneously or separately to vibration along an axis of centripetal force and along an axis perpendicular to the centripetal force axis. The apparatus includes a shaker motor supported by centrifuge arms and a right angle fixture pivotally connected to one of the shaker motor mounts. When the shaker motor vibrates along the centripetal force axis, the vibrations are imparted to a first side of the right angle fixture. The vibrations are transmitted 90 degrees around the pivot and are directed to a second side of the right angle fixture which imparts vibrations perpendicular to the centripetal force axis. The test item is in contact with a third side of the right angle fixture and receives both centripetal-force-axis vibrations and perpendicular axis vibrations simultaneously. A test item can be attached to the third side near the flexible coupling or near the air bag to obtain vibrations along the centripetal force axis or transverse to the centripetal force axis.

Design and fabrication of brazed Rene 41 honeycomb sandwich structural panels for advanced space transportation systems

NASA Technical Reports Server (NTRS)

Hepler, A. K.; Swegle, A. R.

1981-01-01

The design and fabrication of two large brazed Rene 41 honeycomb panels, the establishment of a test plan, the design and fabrication of a test fixture to subject the panels to cyclic thermal gradients and mechanical loads equivalent to those imposed on an advanced space transportation vehicle during its boost and entry trajectories are discussed. The panels will be supported at four points, creating three spans. The outer spans are 45.7 cm (18 in.) and the center span 76.2 cm (30 in). Specimen width is 30.5 cm (12 in.). The panels were primarily designed by boost conditions simulated by subjecting the panels to liquid nitrogen, 77K (-320 F) on one side and 455K (360 F) on the other side and by mechanically imposing loads representing vehicle fuel pressure loads. Entry conditions were simulated by radiant heating to 1034K (1400 F). The test program subjected the panels to 500 boost thermal conditions. Results are presented.

Optimal Design and Damage Tolerance Verification of an Isogrid Structure for Helicopter Application

NASA Technical Reports Server (NTRS)

Baker, Donald J.; Fudge, Jack; Ambur, Damodar R.; Kassapoglou, Christos

2003-01-01

A composite isogrid panel design for application to a rotorcraft fuselage is presented. An optimum panel design for the lower fuselage of the rotorcraft that is subjected to combined in-plane compression and shear loads was generated using a design tool that utilizes a smeared-stiffener theory in conjunction with a genetic algorithm. A design feature was introduced along the edges of the panel that facilitates introduction of loads into the isogrid panel without producing undesirable local bending gradients. A low-cost manufacturing method for the isogrid panel that incorporates these design details is also presented. Axial compression tests were conducted on the undamaged and low-speed impact damaged panels to demonstrate the damage tolerance of this isogrid panel. A combined loading test fixture was designed and utilized that allowed simultaneous application of compression and shear loads to the test specimen. Results from finite element analyses are presented for the isogrid panel designs and these results are compared with experimental results. This study illustrates the isogrid concept to be a viable candidate for application to the helicopter lower fuselage structure.

Design, Fabrication, and Performance of Foil Gas Thrust Bearings for Microturbomachinery Applications

NASA Technical Reports Server (NTRS)

Dykas, Brian; Bruckner, Robert; DellaCorte, Christopher; Edmonds, Brian; Prahl, Joseph

2008-01-01

A methodology for the design and construction of simple foil thrust bearings intended for parametric performance testing and low marginal costs is presented. Features drawn from a review of the open literature are discussed as they relate to bearing performance. The design of fixtures and tooling required to fabricate foil thrust bearings is presented, using conventional machining processes where possible. A prototype bearing with dimensions drawn from the literature is constructed, with all fabrication steps described. A load-deflection curve for the bearing is presented to illustrate structural stiffness characteristics. Start-top cycles are performed on the bearing at a temperature of 425 C to demonstrate early-life wear patterns. A test of bearing load capacity demonstrates useful performance when compared with data obtained from the open literature.

Fixture tests bellows reliability through repetitive pressure/temperature cycling

NASA Technical Reports Server (NTRS)

Levinson, C.

1967-01-01

Fixture explores the reliability of bellows used in precision in inertial systems. The fixture establishes the ability of the bellows to withstand repetitive over-stress pressure cycling at elevated temperatures. It is applicable in quality control and reliability programs.

Comparison of theoretical and flight-measured local flow aerodynamics for a low-aspect-ratio fin

NASA Technical Reports Server (NTRS)

Johnson, J. B.; Sandlin, D. R.

1984-01-01

Flight test and theoretical aerodynamic data were obtained for a flight test fixture mounted on the underside of an F-104G aircraft. The theoretical data were generated using two codes, a two dimensional transonic code called Code H, and a three dimensional subsonic and supersonic code call wing-body. Pressure distributions generated by the codes for the flight test fixture as well as boundary layer displacement thickness generated by the two dimensional code were compared to the flight test data. The two dimensional code pressure distributions compared well except at the minimum pressure point and trailing edge. Shock locations compared well except at high transonic speeds. The three dimensional code pressure distributions compared well except at the trailing edge of the flight test fixture. The two dimensional code does not predict displacement thickness of the flight test fixture well.

Hybrid Residual Flexibility/Mass-Additive Method for Structural Dynamic Testing

NASA Technical Reports Server (NTRS)

Tinker, M. L.

2003-01-01

A large fixture was designed and constructed for modal vibration testing of International Space Station elements. This fixed-base test fixture, which weighs thousands of pounds and is anchored to a massive concrete floor, initially utilized spherical bearings and pendulum mechanisms to simulate Shuttle orbiter boundary constraints for launch of the hardware. Many difficulties were encountered during a checkout test of the common module prototype structure, mainly due to undesirable friction and excessive clearances in the test-article-to-fixture interface bearings. Measured mode shapes and frequencies were not representative of orbiter-constrained modes due to the friction and clearance effects in the bearings. As a result, a major redesign effort for the interface mechanisms was undertaken. The total cost of the fixture design, construction and checkout, and redesign was over $2 million. Because of the problems experienced with fixed-base testing, alternative free-suspension methods were studied, including the residual flexibility and mass-additive approaches. Free-suspension structural dynamics test methods utilize soft elastic bungee cords and overhead frame suspension systems that are less complex and much less expensive than fixed-base systems. The cost of free-suspension fixturing is on the order of tens of thousands of dollars as opposed to millions, for large fixed-base fixturing. In addition, free-suspension test configurations are portable, allowing modal tests to be done at sites without modal test facilities. For example, a mass-additive modal test of the ASTRO-1 Shuttle payload was done at the Kennedy Space Center launch site. In this Technical Memorandum, the mass-additive and residual flexibility test methods are described in detail. A discussion of a hybrid approach that combines the best characteristics of each method follows and is the focus of the study.

Methods of Measuring Stress Relaxation in Composite Tape Springs

DTIC Science & Technology

2015-03-26

plate in order to spread the load evenly and prevent excess torque . The plate also allows for force on the tape spring to be applied to the entire...aluminum squares that can be tightened to the base. The test fixture is secured to the marble base. The tape springs are folded in three locations with...top plate is pressed down by tightening the bolt on each nut. The tightening is complete when the tape spring just begins to create an M shape and

Wire Test Grip Fixture

NASA Technical Reports Server (NTRS)

Burke, Christopher S.

2011-01-01

Wire-testing issues, such as the gripping strains imposed on the wire, play a critical role in obtaining clean data. In a standard test frame fitted with flat wedge grips, the gripping action alone creates stresses on the wire specimen that cause the wire to fail at the grip location. A new test frame, which is outfitted with a vacuum chamber, negated the use of any conventional commercially available wire test fixtures, as only 7 in. (17.8 cm) existed between the grip faces. An innovative grip fixture was designed to test thin gauge wire for a variety of applications in an existing Instron test frame outfitted with a vacuum chamber.

Measurement of impulse peak insertion loss from two acoustic test fixtures and four hearing protector conditions with an acoustic shock tube

PubMed Central

Murphy, William J.; Fackler, Cameron J.; Berger, Elliott H.; Shaw, Peter B.; Stergar, Mike

2015-01-01

Impulse peak insertion loss (IPIL) was studied with two acoustic test fixtures and four hearing protector conditions at the E-A-RCAL Laboratory. IPIL is the difference between the maximum estimated pressure for the open-ear condition and the maximum pressure measured when a hearing protector is placed on an acoustic test fixture (ATF). Two models of an ATF manufactured by the French-German Research Institute of Saint-Louis (ISL) were evaluated with high-level acoustic impulses created by an acoustic shock tube at levels of 134 decibels (dB), 150 dB, and 168 dB. The fixtures were identical except that the E-A-RCAL ISL fixture had ear canals that were 3 mm longer than the National Institute for Occupational Safety and Health (NIOSH) ISL fixture. Four hearing protection conditions were tested: Combat Arms earplug with the valve open, ETYPlugs® earplug, TacticalPro headset, and a dual-protector ETYPlugs earplug with TacticalPro earmuff. The IPILs measured for the E-A-RCAL fixture were 1.4 dB greater than the National Institute for Occupational Safety and Health (NIOSH) ISL ATF. For the E-A-RCAL ISL ATF, the left ear IPIL was 2.0 dB greater than the right ear IPIL. For the NIOSH ATF, the right ear IPIL was 0.3 dB greater than the left ear IPIL. PMID:26356380

SFR test fixture for hemispherical and hyperhemispherical camera systems

NASA Astrophysics Data System (ADS)

Tamkin, John M.

2017-08-01

Optical testing of camera systems in volume production environments can often require expensive tooling and test fixturing. Wide field (fish-eye, hemispheric and hyperhemispheric) optical systems create unique challenges because of the inherent distortion, and difficulty in controlling reflections from front-lit high resolution test targets over the hemisphere. We present a unique design for a test fixture that uses low-cost manufacturing methods and equipment such as 3D printing and an Arduino processor to control back-lit multi-color (VIS/NIR) targets and sources. Special care with LED drive electronics is required to accommodate both global and rolling shutter sensors.

Analysis of shear test method for composite laminates

NASA Technical Reports Server (NTRS)

Bergner, H. W., Jr.; Davis, J. G., Jr.; Herakovich, C. T.

1977-01-01

An elastic plane stress finite element analysis of the stress distributions in four flat test specimens for in-plane shear response of composite materials subjected to mechanical or thermal loads is presented. The shear test specimens investigated include: slotted coupon, cross beam, losipescu, and rail shear. Results are presented in the form of normalized shear contour plots for all three in-plane stess components. It is shown that the cross beam, losipescu, and rail shear specimens have stress distributions which are more than adequate for determining linear shear behavior of composite materials. Laminate properties, core effects, and fixture configurations are among the factors which were found to influence the stress distributions.

Universal nondestructive mm-wave integrated circuit test fixture

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R. (Inventor); Shalkhauser, Kurt A. (Inventor)

1990-01-01

Monolithic microwave integrated circuit (MMIC) test includes a bias module having spring-loaded contacts which electrically engage pads on a chip carrier disposed in a recess of a base member. RF energy is applied to and passed from the chip carrier by chamfered edges of ridges in the waveguide passages of housings which are removably attached to the base member. Thru, Delay, and Short calibration standards having dimensions identical to those of the chip carrier assure accuracy and reliability of the test. The MMIC chip fits in an opening in the chip carrier with the boundaries of the MMIC lying on movable reference planes thereby establishing accuracy and flexibility.

Alignment and testing of critical interface fixtures for the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

McLean, Kyle; Bagdanove, Paul; Berrier, Joshua; Cofie, Emmanuel; Glassman, Tiffany; Hadjimichael, Theodore; Johnson, Eric; Levi, Joshua; Lo, Amy; McMann, Joseph; Ohl, Raymond; Osgood, Dean; Parker, James; Redman, Kevin; Roberts, Vicki; Stephens, Matthew; Sutton, Adam; Wenzel, Greg; Young, Jerrod

2017-08-01

NASA's James Webb Space Telescope (JWST) is a 6.5m diameter, segmented, deployable telescope for cryogenic IR space astronomy. The JWST Observatory architecture includes the Primary Mirror Backplane Support Structure (PMBSS) and Integrated Science Instrument Module (ISIM) Electronics Compartment (IEC) which is designed to integrate to the spacecraft bus via six cup/cone interfaces. Prior to integration to the spacecraft bus, the JWST observatory must undergo environmental testing, handling, and transportation. Multiple fixtures were developed to support these tasks including the vibration fixture and handling and integration fixture (HIF). This work reports on the development of the nominal alignment of the six interfaces and metrology operations performed for the JWST observatory to safely integrate them for successful environmental testing.

Alignment and Testing of Critical Interface Fixtures for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Mclean, Kyle; Bagdanove, Paul; Berrier, Joshua; Cofie, Emmanuel; Glassman, Tiffany; Hadjimichael, Theodore; Johnson, Eric; Levi, Joshua; Lo, Amy; McMann, Joseph;

Alignment and Testing of Critical Interface Fixtures for the James Webb Space Telescope

NASA Technical Reports Server (NTRS)

Mclean, Kyle; Bagdanove, Paul; Berrier, Joshua; Cofie, Emmanuel; Glassman, Tiffany; Hadjimichael, Theodore; Johnson, Eric; Levi, Joshua; Lo, Amy; McMann, Joseph;

Using Bonding Enamel-Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures

DTIC Science & Technology

2010-02-01

Initial tests with enameled metal straps cracked all the test cylinders and straps would not pull out BUILDING STRONG® New Strong Durable Ties...BUILDING STRONG® Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures Principal Investigator: Steven C...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry

Calculating Nozzle Side Loads using Acceleration Measurements of Test-Based Models

NASA Technical Reports Server (NTRS)

Brown, Andrew M.; Ruf, Joe

2007-01-01

As part of a NASA/MSFC research program to evaluate the effect of different nozzle contours on the well-known but poorly characterized "side load" phenomena, we attempt to back out the net force on a sub-scale nozzle during cold-flow testing using acceleration measurements. Because modeling the test facility dynamics is problematic, new techniques for creating a "pseudo-model" of the facility and nozzle directly from modal test results are applied. Extensive verification procedures were undertaken, resulting in a loading scale factor necessary for agreement between test and model based frequency response functions. Side loads are then obtained by applying a wide-band random load onto the system model, obtaining nozzle response PSD's, and iterating both the amplitude and frequency of the input until a good comparison of the response with the measured response PSD for a specific time point is obtained. The final calculated loading can be used to compare different nozzle profiles for assessment during rocket engine nozzle development and as a basis for accurate design of the nozzle and engine structure to withstand these loads. The techniques applied within this procedure have extensive applicability to timely and accurate characterization of all test fixtures used for modal test.A viewgraph presentation on a model-test based pseudo-model used to calculate side loads on rocket engine nozzles is included. The topics include: 1) Side Loads in Rocket Nozzles; 2) Present Side Loads Research at NASA/MSFC; 3) Structural Dynamic Model Generation; 4) Pseudo-Model Generation; 5) Implementation; 6) Calibration of Pseudo-Model Response; 7) Pseudo-Model Response Verification; 8) Inverse Force Determination; 9) Results; and 10) Recent Work.

Fixture for environmental exposure of structural materials under compression load

NASA Technical Reports Server (NTRS)

Clark, R. K.; Lisagor, W. B. (Inventor)

1983-01-01

A device for stressing a deformable material specimen consists of top plate and a bottom plate sandwiching a guide cylinder. The specimen is positioned on the bottom plate and attached to a load piston. Force is applied through the top plate into the guide cylinder. Once the specimen is loaded, the stress is maintained by tightening tie bolt nuts.

Fixtures Hold Nuts During Tightening Of Bolts

NASA Technical Reports Server (NTRS)

Gyekenyesi, John Z.

1993-01-01

Two fixtures designed for use on cross-head of tensile testing machine simplify adjustments of crosshead to accommodate specimens of various lengths. Two cagelike fixtures hold pairs of nuts, preventing nuts from turning while bolts are tightened. Enable one person acting alone to tighten bolts.

Results from a Test Fixture for button BPM Trapped Mode Measurements

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

Cameron,P.; Bacha, B.; Blednykh, A.

2009-05-04

A variety of measures have been suggested to mitigate the problem of button BPM trapped mode heating. A test fixture, using a combination of commercial-off-the-shelf and custom machined components, was assembled to validate the simulations. We present details of the fixture design, measurement results, and a comparison of the results with the simulations. A brief history of the trapped mode button heating problem and a set of design rules for BPM button optimization are presented elsewhere in these proceedings. Here we present measurements on a test fixture that was assembled to confirm, if possible, a subset of those rules: (1)more » Minimize the trapped mode impedance and the resulting power deposited in this mode by the beam. (2) Maximize the power re-radiated back into the beampipe. (3) Maximize electrical conductivity of the outer circumference of the button and minimize conductivity of the inner circumference of the shell, to shift power deposition from the button to the shell. The problem is then how to extract useful and relevant information from S-parameter measurements of the test fixture.« less

High-performance space shuttle auxiliary propellant valve system

NASA Technical Reports Server (NTRS)

Smith, G. M.

1973-01-01

Several potential valve closures for the space shuttle auxiliary propulsion system (SS/APS) were investigated analytically and experimentally in a modeling program. The most promising of these were analyzed and experimentally evaluated in a full-size functional valve test fixture of novel design. The engineering investigations conducted for both model and scale evaluations of the SS/APS valve closures and functional valve fixture are described. Preliminary designs, laboratory tests, and overall valve test fixture designs are presented, and a final recommended flightweight SS/APS valve design is presented.

Apparatus and method of capturing an orbiting spacecraft

NASA Technical Reports Server (NTRS)

Harwell, William D. (Inventor); Gardner, Dale A. (Inventor)

1987-01-01

Apparatus and a method of capturing an orbiting spacecraft by attaching a grapple fixture are discussed. A probe is inserted into an opening, such as a rocket nozzle, in the spacecraft until a stop on the prove mechanism contacts the spacecraft. A lever is actuated releasing a spring loaded rod which moves axially along the probe removing a covering sleeve to expose spring loaded toffle fingers which pivot open engaging the side of the opening. The probe is shortened and tensioned by turning a screw thread, pressing the fingers inside of the opening to compress the spacecraft between the toggle fingers and the stop. A grapple fixture attached to the probe, which is thus secured to the spacecraft, is engaged by appropriate retrieval means such as a remote manipulator arm.

Portable fixture facilitates pressure testing of instrumentation fittings

NASA Technical Reports Server (NTRS)

Olson, G. A.

1967-01-01

Portable fixture facilitates pressure testing to detect possible leaks in instrumentation fittings mounted on tank bulkheads. It uses a vacuum cup which seals a pressure regulator adapter around one side of the fitting to be pressure tested. Leakage is detected with a gas sniffer.

Experimental compliance calibration of the compact fracture toughness specimen

NASA Technical Reports Server (NTRS)

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

1980-01-01

Compliances and stress intensity coefficients were determined over crack length to width ratios from 0.1 to 0.8. Displacements were measured at the load points, load line, and crack mouth. Special fixturing was devised to permit accurate measurement of load point displacement. The results are in agreement with the currently used results of boundary collocation analyses. The errors which occur in stress intensity coefficients or specimen energy input determinations made from load line displacement measurements rather than from load point measurements are emphasized.

Inelastic response of metal matrix composites under biaxial loading

NASA Technical Reports Server (NTRS)

Lissenden, C. J.; Mirzadeh, F.; Pindera, M.-J.; Herakovich, C. T.

1991-01-01

Theoretical predictions and experimental results were obtained for inelastic response of unidirectional and angle ply composite tubes subjected to axial and torsional loading. The composite material consist of silicon carbide fibers in a titanium alloy matrix. This material is known to be susceptible to fiber matrix interfacial damage. A method to distinguish between matrix yielding and fiber matrix interfacial damage is suggested. Biaxial tests were conducted on the two different layup configurations using an MTS Axial/Torsional load frame with a PC based data acquisition system. The experimentally determined elastic moduli of the SiC/Ti system are compared with those predicted by a micromechanics model. The test results indicate that fiber matrix interfacial damage occurs at relatively low load levels and is a local phenomenon. The micromechanics model used is the method of cells originally proposed by Aboudi. Finite element models using the ABACUS finite element program were used to study end effects and fixture specimen interactions. The results to date have shown good correlation between theory and experiment for response prior to damage initiation.

Optical Alignment of the JWST ISIM to the OTE Simulator (OSIM): Current Concept and Design Studies

NASA Technical Reports Server (NTRS)

Frey, Bradley J.; Davila, Pamela S.; Marsh, James M.; Ohl, Raymond G.; Sullivan, Joseph

2007-01-01

The James Webb Space Telescope's (JWST) Integrated Science Instrument Module (ISIM) is the scientific payload of the observatory and contai ns four science instruments. During alignment and test of the integrated ISIM (i.e. ISIM + science instruments) at NASA's Goddard Space Fli ght Center (GSFC), the Optical telescope element SIMulator (OSIM) wil l be used to optically stimulate the science instruments to verify their operation and performance. In this paper we present the design of two cryogenic alignment fixtures that will be used to determine and verify the proper alignment of OSIM to ISIM during testing at GSFC. The se fixtures, the Master Alignment Target Fixture (MATF) and the ISIM Alignment Target Fixture (IATF), will provide continuous, 6 degree of freedom feedback to OSIM during initial ambient alignment as well as during cryogenic vacuum testing.

Buckling Behavior of Compression-Loaded Quasi-Isotropic Curved Panels with a Circular Cutout

NASA Technical Reports Server (NTRS)

Hilburger, Mark W.; Britt, Vicki O.; Nemeth, Michael P.

1999-01-01

Results from a numerical and experimental study of the response of compression-loaded quasi-isotropic curved panels with a centrally located circular cutout are presented. The numerical results were obtained by using a geometrically nonlinear finite element analysis code. The effects of cutout size, panel curvature and initial geo- metric imperfections on the overall response of compression-loaded panels are described. In addition, results are presented from a numerical parametric study that indicate the effects of elastic circumferential edge restraints on the prebuckling and buckling response of a selected panel and these numerical results are compared to experimentally measured results. These restraints are used to identify the effects of circumferential edge restraints that are introduced by the test fixture that was used in the present study. It is shown that circumferential edge restraints can introduce substantial nonlinear prebuckling deformations into shallow compression-loaded curved panels that can results in a significant increase in buckling load.

Critical Current of Superconducting Rutherford Cable in High Magnetic Fields with Transverse Pressure

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

Dietderich, D.R.; Scanlan, R.M.; Walsh, R.P.

For high energy physics applications superconducting cables are subjected to large stresses and high magnetic fields during service. It is essential to know how these cables perform in these operating conditions. A loading fixture capable of applying loads of up to 700 kN has been developed by NHMFL for LBNL. This fixture permits uniform loading of straight cables over a 122 mm length in a split-pair solenoid in fields up to 12 T at 4.2 K. The first results from this system for Rutherford cables of internal-tin and modified jelly roll strand of Nb{sub 3}Sn produced by IGC and TWCmore » showed that little permanent degradation occurs up to 210 MPa. However, the cable made from internal-tin strand showed a 40% reduction in K{sub c} at 11T and 210 MPa while a dable made from modified jelly roll material showed only a 15% reduction in I{sub c} at 11T and 185 MPa.« less

Universal test fixture for monolithic mm-wave integrated circuits calibrated with an augmented TRD algorithm

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R.; Shalkhauser, Kurt A.

1989-01-01

The design and evaluation of a novel fixturing technique for characterizing millimeter wave solid state devices is presented. The technique utilizes a cosine-tapered ridge guide fixture and a one-tier de-embedding procedure to produce accurate and repeatable device level data. Advanced features of this technique include nondestructive testing, full waveguide bandwidth operation, universality of application, and rapid, yet repeatable, chip-level characterization. In addition, only one set of calibration standards is required regardless of the device geometry.

Deployable Aeroshell Flexible Thermal Protection System Testing

NASA Technical Reports Server (NTRS)

Hughes, Stephen J.; Ware, Joanne S.; DelCorso, Joseph A.; Lugo, Rafael A.

2009-01-01

Deployable aeroshells offer the promise of achieving larger aeroshell surface areas for entry vehicles than otherwise attainable without deployment. With the larger surface area comes the ability to decelerate high-mass entry vehicles at relatively low ballistic coefficients. However, for an aeroshell to perform even at the low ballistic coefficients attainable with deployable aeroshells, a flexible thermal protection system (TPS) is required that is capable of surviving reasonably high heat flux and durable enough to survive the rigors of construction handling, high density packing, deployment, aerodynamic loading and aerothermal heating. The Program for the Advancement of Inflatable Decelerators for Atmospheric Entry (PAIDAE) is tasked with developing the technologies required to increase the technology readiness level (TRL) of inflatable deployable aeroshells, and one of several of the technologies PAIDAE is developing for use on inflatable aeroshells is flexible TPS. Several flexible TPS layups were designed, based on commercially available materials, and tested in NASA Langley Research Center's 8 Foot High Temperature Tunnel (8ft HTT). The TPS layups were designed for, and tested at three different conditions that are representative of conditions seen in entry simulation analyses of inflatable aeroshell concepts. Two conditions were produced in a single run with a sting-mounted dual wedge test fixture. The dual wedge test fixture had one row of sample mounting locations (forward) at about half the running length of the top surface of the wedge. At about two thirds of the running length of the wedge, a second test surface drafted up at five degrees relative to the first test surface established the remaining running length of the wedge test fixture. A second row of sample mounting locations (aft) was positioned in the middle of the running length of the second test surface. Once the desired flow conditions were established in the test section the dual wedge test fixture, oriented at 5 degrees angle of attack down, was injected into the flow. In this configuration the aft sample mounting location was subjected to roughly twice the heat flux and surface pressure of the forward mounting location. The tunnel was run at two different conditions for the test series: 1) 'Low Pressure', and 2) 'High Pressure'. At 'Low Pressure' conditions the TPS layups were tested at 6W/cm2 and 11W/cm2 while at 'High Pressure' conditions the TPS layups were tested at 11W/cm2 and 20W/cm2. This paper details the test configuration of the TPS samples in the 8Ft HTT, the sample holder assembly, TPS sample layup construction, sample instrumentation, results from this testing, as well as lessons learned.

LSRA STS Tire Test - on rim

NASA Technical Reports Server (NTRS)

1995-01-01

From 1993 to 1995, in conjunction with other NASA centers, NASA Dryden Flight Research Center, Edwards, California, used a Convair CV-990 airplane as a Landing Systems Research Aircraft (LSRA) to perform Space Shuttle tire tests. The results provided the Space Shuttle Program with data to support its flight rules and enabled it to resurface a grooved runway at Kennedy Space Center that had added unnecessary wear to the Space Shuttle tires. Tests were done using a unique fixture mounted in the center of the CV-990 fuselage, between the main landing gear. Landing gear systems from other aircraft could be attached to the test fixture, which lowered them to the runway surface during actual landings. The LSRA had the ability to reproduce the loads and speeds of the other aircraft, as well as simulate crosswind landing conditions in a safe, controlled environment. The video clip shows a landing on the concrete runway at Edwards, California on August 11, 1995, which concluded the Space Shuttle gear research program. As the Space Shuttle tire was lowered onto the surface, it was destroyed almost instantly. The rim scraped on the concrete, and stopped rolling as it became flat. It heated up and left a flaming trail of hot rubber and aluminum alloy particles. Notice how the fire quickly went out as the test gear was raised, indicating a safer condition than prevailed in a lakebed landing.

Additive Manufacturing of Advanced High Temperature Masking Fixtures for EBPVD TBC Coating

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

List, III, Frederick Alyious; Feuerstein, Albert; Dehoff, Ryan

2016-03-30

The purpose of this Manufacturing Demonstration Facility (MDF) technical collaboration project between Praxair Surface Technologies, Inc. (PST) and Oak Ridge National Laboratory (ORNL) was to develop an additive manufacturing process to fabricate next generation high temperature masking fixtures for coating of turbine airfoils with ceramic Thermal Barrier Coatings (TBC) by the Electron Beam Physical Vapor Deposition (EBPVD) process. Typical masking fixtures are sophisticated designs and require complex part manipulation in order to achieve the desired coating distribution. Fixtures are typically fabricated from high temperature nickel (Ni) based superalloys. The fixtures are fabricated from conventional processes by welding of thin sheetmore » material into a complex geometry, to decrease the weight load for the manipulator and to reduce the thermal mass of the fixture. Recent attempts have been made in order to fabricate the fixtures through casting, but thin walled sections are difficult to cast and have high scrap rates. This project focused on understanding the potential for fabricating high temperature Ni based superalloy fixtures through additive manufacturing. Two different deposition processes; electron beam melting (EBM) and laser powder bed fusion were evaluated to determine the ideal processing route of these materials. Two different high temperature materials were evaluated. The high temperature materials evaluated were Inconel 718 and another Ni base alloy, designated throughout the remainder of this document as Alloy X, as the alloy composition is sensitive. Inconel 718 is a more widely utilized material for additive manufacturing although it is not currently the material utilized for current fixtures. Alloy X is the alloy currently used for the fixtures, but is not a commercially available alloy for additive manufacturing. Praxair determined it was possible to build the fixture using laser powder bed technology from Inconel 718. ORNL fabricated the fixture geometry using the EBM technology in order to compare deposition features such as surface roughness, geometric accuracy, deposition rate, surface and subsurface porosity, and material quality. It was determined that the laser powder bed technology was ideal for the geometry and requirements of the fixture set by Praxair, and Praxair moved forward with the purchase of a laser powder bed system. The subsequent portion of the project focused on determining the ideal processing parameters for alloy X for the laser powder bed system using ORNL’s Renishaw laser powder bed system. Praxair supplied gas atomized powders of alloy X material with properties specified by ORNL. ORNL printed text cube arrays in order to determine the ideal combination of laser powder and laser travel speed in order to maximize material density, improve surface quality, and maintain geometric accuracy. Additional powder supplied by Praxair was used to fabricate a full-scale fixture component.« less

CM-2 Environmental / Modal Testing of Spacehab Racks

NASA Technical Reports Server (NTRS)

McNelis, Mark E.; Goodnight, Thomas W.; Farkas, Michael A.

2001-01-01

Combined environmental/modal vibration testing has been implemented at the NASA Glenn Research Center's Structural Dynamics Laboratory. The benefits of combined vibration testing are that it facilitates test article modal characterization and vibration qualification testing. The Combustion Module-2 (CM-2) is a space experiment that launches on Shuttle mission STS 107 in the SPACEHAB Research Double Module. The CM-2 flight hardware is integrated into a SPACEHAB single and double rack. CM-2 rack level combined vibration testing was recently completed on a shaker table to characterize the structure's modal response and verify the random vibration response. Control accelerometers and limit force gauges, located between the fixture and rack interface, were used to verify the input excitation. Results of the testing were used to verify the loads and environments for flight on the Shuttle.

4th Day of Equipment Being Loaded for Recovery of Orion

NASA Image and Video Library

2014-11-20

A forklift is used to set the Orion handling fixture down in the well deck of the USS Anchorage at Naval Base San Diego in California. The fixture and other ground support equipment will be used during recovery of the Orion crew module after its first flight test. Before launch of Orion on a Delta IV Heavy rocket from Cape Canaveral Air Force Station in Florida, NASA, Lockheed Martin and U.S. Navy personnel will head out to sea in the USS Anchorage and the USNS Salvor, a salvage ship, and wait for splashdown of the Orion crew module in the Pacific Ocean. The Ground Systems Development and Operations Program will lead the recovery efforts. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted flight test of Orion is scheduled to launch in December atop a United Launch Alliance Delta IV Heavy rocket and in 2018 on NASA’s Space Launch System rocket.

Case Studies of Rock Reinforcement Components and Systems Testing

NASA Astrophysics Data System (ADS)

Thompson, A. G.; Villaescusa, E.

2014-09-01

Rock reinforcement is widely used in tunnels and surface and underground mines. A large number of proprietary products are available in various configurations of components. While the mechanical properties of the primary element are available from product brochures, the associated component properties may vary widely and adversely influence the overall performance of the system. Field pull out tests are most commonly used to measure the system response in the toe anchor region. However, the response of the collar region is less commonly considered but may be more important. Several case studies are described in which various components and systems of rock bolts and cable bolts have been subjected to static loading in the laboratory and in the field. The results generally demonstrate the importance of considering the properties of all the components and not simply those of the primary element. In some cases, the internal fixtures have strengths much less than the elements. Often it has also been found that the fixture at the collar has significantly less strength than the element and this will result in complete loss of function in restraining surface support hardware, such as plates, mesh and reinforced shotcrete.

High power s-band vacuum load

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

Neubauer, Michael; Dudas, Alan; Krasnykh, Anatoly

Through a combination of experimentation and calculation the components of a novel room temperature dry load were successfully fabricated. These components included lossy ceramic cylinders of various lengths, thicknesses, and percent of silicon carbide (SiC). The cylinders were then assembled into stainless steel compression rings by differential heating of the parts and a special fixture. Post machining of this assembly provided a means for a final weld. The ring assemblies were then measured for S-parameters, individually and in pairs using a low-cost TE10 rectangular to TE01 circular waveguide adapter specially designed to be part of the final load assembly. Matchedmore » pairs of rings were measured for assembly into the final load, and a sliding short designed and fabricated to assist in determining the desired short location in the final assembly. The plan for the project was for Muons, Inc. to produce prototype loads for long-term testing at SLAC. The STTR funds for SLAC were to upgrade and operate their test station to ensure that the loads would satisfy their requirements. Phase III was to be the sale to SLAC of loads that Muons, Inc. would manufacture. However, an alternate solution that involved a rebuild of the old loads, reduced SLAC budget projections, and a relaxed time for the replacement of all loads meant that in-house labor will be used to do the upgrade without the need for the loads developed in this project. Consequently, the project was terminated before the long term testing was initiated. However, SLAC can use the upgraded test stand to compare the long-term performance of the ones produced in this project with their rebuilt loads when they are available.« less

Design, fabrication, and initial test of a fixture for reducing the natural frequency of the Mod-O wind turbine tower

NASA Technical Reports Server (NTRS)

Winemiller, J. R.; Sullivan, T. L.; Sizemore, R. L.; Yee, S. T.

1979-01-01

It was desired to observe the behavior of a two bladed wind turbine where the tower first bending natural frequency is less than twice the rotor speed. The system then passes through resonance when accelerating to operating speed. The frequency of the original Mod-O tower was reduced by placing it on a spring fixture. The fixture is adjustable to provide a range of tower bending frequencies. Fixture design details are given and behavior during initial operation is described.

Demagnetization Tests Performed on a Linear Alternator for a Stirling Power Convertor

NASA Technical Reports Server (NTRS)

Geng, Steven M.; Niedra, Janis M.; Schwarze, Gene E.

2012-01-01

The NASA Glenn Research Center (GRC) is conducting in-house research on rare-earth permanent magnets and linear alternators to assist in developing free-piston Stirling convertors for radioisotope space power systems and for developing advanced linear alternator technology. This research continues at GRC, but, with the exception of Advanced Stirling Radioisotope Generator references, the work presented in this paper was conducted in 2005. A special arc-magnet characterization fixture was designed and built to measure the M-H characteristics of the magnets used in Technology Demonstration Convertors developed under the 110-W Stirling Radioisotope Generator (SRG110) project. This fixture was used to measure these characteristics of the arc magnets and to predict alternator demagnetization temperatures in the SRG110 application. Demagnetization tests using the TDC alternator on the Alternator Test Rig were conducted for two different magnet grades: Sumitomo Neomax 44AH and 42AH. The purpose of these tests was to determine the demagnetization temperatures of the magnets for the alternator under nominal loads. Measurements made during the tests included the linear alternator terminal voltage, current, average power, magnet temperatures, and stator temperatures. The results of these tests were found to be in good agreement with predictions. Alternator demagnetization temperatures in the Advanced Stirling Convertor (ASC-developed under the Advanced Stirling Radioisotope Generator project) were predicted as well because the prediction method had been validated through the SRG110 alternator tests. These predictions led to a specification for maximum temperatures of the ASC pressure vessel.

Mammalian Toxicology Testing: Problem Definition Study, Technical Plan.

DTIC Science & Technology

1981-03-01

Acute Oral Exposure Area, Rzdent 2. Subchrcnic Oral Exposure Area, .odent 3. Chronic Oral Exposure Area, Rodent 4. Subchronic Oral Eposure Area, "og...Alarms Fire Extinguisher First Aid Fiscal Year Record Fixtures (See Jigs, Fixtures & Molds Control System) Food Preparation/Blending Forms Control...Insurance Invoicing (See Bookkeeping) Janitorial Service Jigs, Fixtures & Molds Control System Key Control System Keypunch Control System Label

Distributed Aerodynamic Sensing and Processing Toolbox

NASA Technical Reports Server (NTRS)

Brenner, Martin; Jutte, Christine; Mangalam, Arun

2011-01-01

A Distributed Aerodynamic Sensing and Processing (DASP) toolbox was designed and fabricated for flight test applications with an Aerostructures Test Wing (ATW) mounted under the fuselage of an F-15B on the Flight Test Fixture (FTF). DASP monitors and processes the aerodynamics with the structural dynamics using nonintrusive, surface-mounted, hot-film sensing. This aerodynamic measurement tool benefits programs devoted to static/dynamic load alleviation, body freedom flutter suppression, buffet control, improvement of aerodynamic efficiency through cruise control, supersonic wave drag reduction through shock control, etc. This DASP toolbox measures local and global unsteady aerodynamic load distribution with distributed sensing. It determines correlation between aerodynamic observables (aero forces) and structural dynamics, and allows control authority increase through aeroelastic shaping and active flow control. It offers improvements in flutter suppression and, in particular, body freedom flutter suppression, as well as aerodynamic performance of wings for increased range/endurance of manned/ unmanned flight vehicles. Other improvements include inlet performance with closed-loop active flow control, and development and validation of advanced analytical and computational tools for unsteady aerodynamics.

Explosive Venting Technology for Cook-Off Response Mitigation

DTIC Science & Technology

2010-07-01

endplate blew off 188.3 PAX-28 Go 6.4 Explode, HE boiled out, body banana peeled 177.8 PAX-28 No go 7.6 Burn, HE boiled out of fixture, smoking, then burn...PAX-28 5.1-mm diameter vent test was to blow off the top fixture and peel off three out of the four heating bands while leaving the fixture in its

The Aerostructures Test Wing (ATW), which consisted of an 18-inch carbon fiber test wing with surface-mounted piezoelectric strain actuators, was mounted on a special ventral flight test fixture and flown on Dryden's F-15B Research Testbed aircraft

NASA Image and Video Library

2001-03-28

The Aerostructures Test Wing (ATW), which consisted of an 18-inch carbon fiber test wing with surface-mounted piezoelectric strain actuators, was mounted on a special ventral flight test fixture and flown on Dryden's F-15B Research Testbed aircraft

CM-2 Environmental/Modal Testing of SPACEHAB Racks

NASA Technical Reports Server (NTRS)

McNelis, Mark E.; Goodnight, Thomas W.

2001-01-01

Combined environmental/modal vibration testing has been implemented at the NASA Glenn Research Center's Structural Dynamics Laboratory. The benefits of combined vibration testing are that it facilitates test article modal characterization and vibration qualification testing. The Combustion Module-2 (CM-2) is a space experiment that will launch on shuttle mission STS-107 in the SPACEHAB Research Double Module. The CM-2 flight hardware is integrated into a SPACEHAB single and double rack. CM-2 rack-level combined vibration testing was recently completed on a shaker table to characterize the structure's modal response and verify the random vibration response. Control accelerometers and limit force gauges, located between the fixture and rack interface, were used to verify the input excitation. Results of the testing were used to verify the loads and environments for flight on the shuttles.

30 CFR 56.3203 - Rock fixtures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... similar strata, opening dimensions and ground stresses in any mine; or (2) Have been tested and shown to... dimensions, and ground stresses as the area where the fixtures are expected to be used. During the test... the rock. (2) The torque of the first bolt, every tenth bolt, and the last bolt installed in each work...

30 CFR 56.3203 - Rock fixtures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... similar strata, opening dimensions and ground stresses in any mine; or (2) Have been tested and shown to... dimensions, and ground stresses as the area where the fixtures are expected to be used. During the test... the rock. (2) The torque of the first bolt, every tenth bolt, and the last bolt installed in each work...

Microelectronics Instrument Products Shock and Vibration Electro-Optics. Section B; Acceptance Data Package

NASA Technical Reports Server (NTRS)

1995-01-01

The motor/encoder (henceforth referred to as the UUT) test sequence began with a baseline functional evaluation, which demonstrated that the motor satisfied the operating torque, cogging torque, winding resistance, and mechanical requirements of SOW. In addition, the encoder electrical requirements were verified, as well as the alignment of the encoder outputs relative to the motor shaft position. There were no discrepancies observed in this portion of the test. The UUT was then exposed to a number of environments, including thermal vacuum, thermal cycling, random and sine vibration, and mechanical shock. During the thermal environments, the performance of the UUT under load was verified at specified points in the cycles, as described in ATP 20049. In addition, the UUT was bench tested between the two thermal environments. No anomalies were observed during the thermal tests. The vibration and shock tests were performed by East-West Technology Corporation, West Babylon, New York. The UUT was delivered to the lab in a sealed vibration fixture in order to maintain the cleanliness levels required by the SOW. In addition, a three ounce load was attached to the motor shaft. The attachment method of this load caused damage to the shaft and bearing during random vibration of S/N 0003 on April 28, 1995, and is described further in NCR 00168.

Quasi-Static Indentation Analysis of Carbon-Fiber Laminates.

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

Briggs, Timothy; English, Shawn Allen; Nelson, Stacy Michelle

2015-12-01

A series of quasi - static indentation experiments are conducted on carbon fiber reinforced polymer laminates with a systematic variation of thicknesses and fixture boundary conditions. Different deformation mechanisms and their resulting damage mechanisms are activated b y changing the thickn ess and boundary conditions. The quasi - static indentation experiments have been shown to achieve damage mechanisms similar to impact and penetration, however without strain rate effects. The low rate allows for the detailed analysis on the load response. Moreover, interrupted tests allow for the incremental analysis of various damage mechanisms and pr ogressions. The experimentally tested specimens aremore » non - destructively evaluated (NDE) with optical imaging, ultrasonics and computed tomography. The load displacement responses and the NDE are then utilized in numerical simulations for the purpose of model validation and vetting. The accompanying numerical simulation work serves two purposes. First, the results further reveal the time sequence of events and the meaning behind load dro ps not clear from NDE . Second, the simulations demonstrate insufficiencies in the code and can then direct future efforts for development.« less

OH-58 Composite Main Rotor Blade Preliminary Design Investigation

DTIC Science & Technology

1978-11-01

of Damage on Root Loads. . . .... .......... 138 59 Effect of Damage on Fixed Hub Vertical Forces . . . 139 60 Schematic of Impact Test Fixture...LINE C •.. ~~OSTN .-- cs VRr -7 Ai . 60 (TYP)1.65] 3.30 "TWIST REp? LINE e ~ ~ ~ _l H,,i...%-.lORI.ZONTAL REF $UNE .- 2. 4 .. , +-+ Figure 4. OH-58C/A...I 0 -- . .. . . . . -- - -- _ . .. I-z _-- .. ~>0 co 0 0 4 wU) 04 C;C4t44 %0 400 a cH cmI C4 to co 4a co 60 c 0 1 o c4 % ol WA

Load regulating expansion fixture

DOEpatents

Wagner, Lawrence M.; Strum, Michael J.

1998-01-01

A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components.

Rotating Juno for Integrating Instruments

NASA Image and Video Library

2010-07-12

Once the radiation vault was installed on top of the propulsion module, NASA Juno spacecraft was lifted onto a large rotation fixture. The fixture allows the spacecraft to be turned for convenient access for integrating and testing instruments.

Sandia Internship Fall 2014

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

Kuhn, Joshua

2015-01-01

While working at Sandia National Laboratories as a graduate intern from September 2014 to January 2015, most of my time was spent on two projects. The first project involved designing a test fixture for circuit boards used in a recording device. The test fixture was needed to decrease test set up time. The second project was to use optimization techniques to determine the optimal G-Switch for given acceleration profiles.

O-Ring-Testing Fixture

NASA Technical Reports Server (NTRS)

Turner, James E.; Mccluney, D. Scott

1991-01-01

Fixture tests O-rings for sealing ability under dynamic conditions after extended periods of compression. Hydraulic cylinder moves plug in housing. Taper of 15 degrees on plug and cavity of housing ensures that gap created between O-ring under test and wall of cavity. Secondary O-rings above and below test ring maintain pressure applied to test ring. Evaluates effects of variety of parameters, including temperature, pressure, rate of pressurization, rate and magnitude of radial gap movement, and pretest compression time.

Samus Counter Lifting Fixture

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

Stredde, H.; /Fermilab

1998-05-27

A lifting fixture has been designed to handle the Samus counters. These counters are being removed from the D-zero area and will be transported off site for further use at another facility. This fixture is designed specifically for this particular application and will be transferred along with the counters. The future use of these counters may entail installation at a facility without access to a crane and therefore a lift fixture suitable for both crane and/or fork lift usage has been created The counters weigh approximately 3000 lbs. and have threaded rods extended through the counter at the top comersmore » for lifting. When these counters were first handled/installed these rods were used in conjunction with appropriate slings and handled by crane. The rods are secured with nuts tightened against the face of the counter. The rod thread is M16 x 2({approx}.625-inch dia.) and extends 2-inch (on average) from the face of the counter. It is this cantilevered rod that the lift fixture engages with 'C' style plates at the four top comers. The strongback portion of the lift fixture is a steel rectangular tube 8-inch (vertical) x 4-inch x .25-inch wall, 130-inch long. 1.5-inch square bars are welded perpendicular to the long axis of the rectangular tube at the appropriate lift points and the 'C' plates are fastened to these bars with 3/4-10 high strength bolts -grade 8. Two short channel sections are positioned-welded-to the bottom of the rectangular tube on 40 feet centers, which are used as locators for fork lift tines. On the top are lifting eyes for sling/crane usage and are rated at 3500 lbs. safe working load each - vertical lift only.« less

Preliminary eddy current modelling for the large angle magnetic suspension test fixture

NASA Technical Reports Server (NTRS)

Britcher, Colin

1994-01-01

This report presents some recent developments in the mathematical modeling of the Large Angle Magnetic Suspension Test Fixture (LAMSTF) at NASA Langley Research Center. It is shown that these effects are significant, but may be amenable to analysis, modeling and measurement. A theoretical framework is presented, together with a comparison of computed and experimental data.

NASA Dryden's new in-house designed Propulsion Flight Test Fixture (PFTF), carried on an F-15B's centerline attachment point, underwent flight envelope expansion in order to verify its design and capabilities.

NASA Image and Video Library

2001-11-30

NASA Dryden's new in-house designed Propulsion Flight Test Fixture (PFTF), carried on an F-15B's centerline attachment point, underwent flight envelope expansion in order to verify its design and capabilities.

Viking 1975 Orbiter Development Test Model/Lander Dynamic Test Model dynamic environmental testing - An overview

NASA Technical Reports Server (NTRS)

Milder, G.

1975-01-01

The current work presents an overview of the Viking 1975 environmental testing from an engineering standpoint. An extremely large vibration test fixture had to be designed, analyzed, and integrated into a test setup that employed hydrostatic bearings in a new fashion. A vibration control system was also required that would allow for thirty-six channels of sine-wave peak select control from acceleration, force-of-strain transducers. In addition, some 68 channels of peak limiting shutdown capability were needed for backup and monitoring of other data during the forced vibration test. Pretesting included analyses of the fixture design, overturning moment, control system capabilities, and response of the entire spacecraft/fixture/exciter system to the test environment. Closed-loop control for acoustic testing was a necessity due to the fact that the Viking spacecraft took up a major portion of the volume of the 10,000 cu ft chamber. The spacecraft emerged from testing undamaged.

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.

Improved Tensile Adhesion Specimens for High Strength Epoxy Systems in Aerospace Applications

NASA Technical Reports Server (NTRS)

Haddock, M. Reed; McLennan, Michael L.

2000-01-01

An improved tensile adhesion button has been designed and tested that results in higher measured tensile adhesion strength while providing increased capability for testing high strength epoxy adhesive systems. The best attributes of two well-established tensile button designs were combined and refined into an optimized tensile button. The most significant design change to the tensile button was to improve alignment of the bonded tensile button specimens during tensile testing by changing the interface between the tensile button and the tensile test machine. The established or old button design uses a test fixture that pulls from a grooved annulus or anvil head while the new button design pulls from a threaded hole in the centerline of the button. Finite element (FE) analysis showed that asymmetric loading of the established anvil head tensile button significantly increases the stress concentration in the adhesive, causing failure at lower tensile test loads. The new tensile button was designed to eliminate asymmetric loading and eliminate misalignment sensitivity. Enhanced alignment resulted in improved tensile adhesion strength measurement up to 13.8 MPa (2000psi) over the established button design. Another design change increased the capability of the button by increasing the threaded hole diameter allowing it to test high strength epoxy systems up to 85 MPa(less than 12,000 psi). The improved tensile button can be used in button- to-button or button-to-panel configurations.

Influence of the implant abutment types and the dynamic loading on initial screw loosening

PubMed Central

Kim, Eun-Sook

2013-01-01

PURPOSE This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading. MATERIALS AND METHODS Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at 30° to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for 105 cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (α=0.05). RESULTS Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences. CONCLUSION The abutment types did not have a significant influence on short term screw loosening. On the other hand, after 105 cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not. PMID:23509006

Alignment verification procedures

NASA Technical Reports Server (NTRS)

Edwards, P. R.; Phillips, E. P.; Newman, J. C., Jr.

1988-01-01

In alignment verification procedures each laboratory is required to align its test machines and gripping fixtures to produce a nearly uniform tensile stress field on an un-notched sheet specimen. The blank specimens (50 mm w X 305 mm l X 2.3 mm th) supplied by the coordinators were strain gauged. Strain gauge readings were taken at all gauges (n = 1 through 10). The alignment verification procedures are as follows: (1) zero all strain gauges while specimen is in a free-supported condition; (2) put strain-gauged specimen in the test machine so that specimen front face (face 1) is in contact with reference jaw (standard position of specimen), tighten grips, and at zero load measure strains on all gauges. (epsilon sub nS0 is strain at gauge n, standard position, zero load); (3) with specimen in machine and at a tensile load of 10 kN measure strains (specimen in standard position). (Strain = epsilon sub nS10); (4) remove specimen from machine. Put specimen in machine so that specimen back face (face 2) is in contact with reference jaw (reverse position of specimen), tighten grips, and at zero load measure strains on all gauges. (Strain - epsilon sub nR0); and (5) with specimen in machine and at tensile load of 10 kN measure strains (specimen in reverse position). (epsilon sub nR10 is strain at gauge n, reverse position, 10 kN load).

Mechanical properties of resin glass fiber-reinforced abutment in comparison to titanium abutment

PubMed Central

Andreasi Bassi, Mirko; Bedini, Rossella; Pecci, Raffella; Ioppolo, Pietro; Lauritano, Dorina; Carinci, Francesco

2015-01-01

Purpose: So far, definitive implant abutments have been performed with high elastic modulus materials, which prevented any type of shock absorption of the chewing loads and as a consequence, the protection of the bone-fixture interface. This is particularly the case when the esthetic restorative material chosen is ceramic rather than composite resin. The adoption of an anisotropic abutment, characterized by an elastic deformability, could allow decreasing the impulse of chewing forces transmitted to the crestal bone. Materials and Methods: According to research protocol, the mechanical resistance to cyclical load was evaluated in a tooth-colored fiber-reinforced abutment (TCFRA) prototype and compared to that of a titanium abutment (TA), thus eight TCFRAs and eight TAs were adhesively cemented on as many titanium implants. The swinging that the two types of abutments showed during the application of sinusoidal load was also analyzed. Results: In the TA group, both fracture and deformation occurred in 12.5% of samples while debonding 62.5%. In the TCFRA group, only debonding was present in 37.5% of samples. In comparison to the TAs, the TCFRAs exhibited a greater swinging during the application of sinusoidal load. In the TA group, the extrusion prevailed, whereas in the TCFRA group, the intrusion was more frequent. Conclusion: The greater elasticity of TCFRA to the flexural load allows absorbing part of the transversal load applied on the fixture during the chewing function, thus reducing the stress on the bone-implant interface. PMID:26229266

Finite Elements Analysis of a Composite Semi-Span Test Article With and Without Discrete Damage

NASA Technical Reports Server (NTRS)

Lovejoy, Andrew E.; Jegley, Dawn C. (Technical Monitor)

2000-01-01

AS&M Inc. performed finite element analysis, with and without discrete damage, of a composite semi-span test article that represents the Boeing 220-passenger transport aircraft composite semi-span test article. A NASTRAN bulk data file and drawings of the test mount fixtures and semi-span components were utilized to generate the baseline finite element model. In this model, the stringer blades are represented by shell elements, and the stringer flanges are combined with the skin. Numerous modeling modifications and discrete source damage scenarios were applied to the test article model throughout the course of the study. This report details the analysis method and results obtained from the composite semi-span study. Analyses were carried out for three load cases: Braked Roll, LOG Down-Bending and 2.5G Up-Bending. These analyses included linear and nonlinear static response, as well as linear and nonlinear buckling response. Results are presented in the form of stress and strain plots. factors of safety for failed elements, buckling loads and modes, deflection prediction tables and plots, and strainage prediction tables and plots. The collected results are presented within this report for comparison to test results.

Load regulating expansion fixture

DOEpatents

Wagner, L.M.; Strum, M.J.

1998-12-15

A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils is disclosed. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located therebetween. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components. 1 fig.

Test Operations Procedure (TOP) 6-3-044. Optical Transfer Function

DTIC Science & Technology

2009-07-27

Mounting Fixtures As required Alignment Periscope See section 4.1.6 TOP 6-3-040 27 July 2009 3 3. REQUIRED TEST CONDITIONS. 3.1 Pre-test...carefully selected. The stabilized cast iron lathe bed type, typically 2-3 m long, provides adequate support for mounting the various assemblies...combined size and weight of some vehicle mounted sights, a special mounting fixture , perhaps including a periscopic system may be required. It is

Spectroscopic temperature measurements in interior ballistic environments

NASA Astrophysics Data System (ADS)

Klingenberg, G.; Mach, H.

1984-11-01

Spectroscopic temperature measurements during the interior ballistic cycle of a 20 mm test fixture gun and inside the muzzle flash of a 7.62 mm rifle are described. The investigation yields information on temperature distribution in the burning propellant charge of the 20 mm test fixture and on radial temperature profiles in the 7.62 mm muzzle flash region. A technique to obtain temperature during the ignition and combustion within the 20 mm propellant charge is presented. Additional in-bore measurements by quartz windows mounted into bores along the barrel and emission-absorption measurements inside the muzzle flash of the 20 mm test fixture yield a complete temperature profile for the gun system. Spectroscopic infrared measurements inside the muzzle flash of a 7.62 mm rifle complete the investigation.

Space vehicle electromechanical system and helical antenna winding fixture

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

Judd, Stephen; Dallmann, Nicholas; Guenther, David

A space vehicle electromechanical system may employ an architecture that enables convenient and practical testing, reset, and retesting of solar panel and antenna deployment on the ground. A helical antenna winding fixture may facilitate winding and binding of the helical antenna.

An Evaluation of the Iosipescu Specimen for Composite Materials Shear Property Measurement. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Ho, Henjen

1991-01-01

A detailed evaluation of the suitability of the Iosipescu specimen tested in the modified Wyoming fixture is presented. An experimental investigation using conventional strain gage instrumentation and moire interferometry is performed. A finite element analysis of the Iosipescu shear test for unidirectional and cross-ply composites is used to assess the uniformity of the shear stress field in the vicinity of the notch, and demonstrate the effect of the nonuniform stress field upon the strain gage measurements used for the determination of composite shear moduli. From the test results for graphite-epoxy laminates, it is shown that the proximity of the load introduction point to the test section greatly influences the individual gage readings for certain fiber orientations but the effect upon shear modulus measurement is relatively unimportant. A numerical study of the load contact effect shows the sensitivity of some fiber configurations to the specimen/fixture contact mechanism and may account for the variations in the measured shear moduli. A comparison of the strain gage readings from one surface of a specimen with corresponding data from moire interferometry on the opposite face documented an extreme sensitivity of some fiber orientations to eccentric loading which induced twisting and yielded spurious shear stress-strain curves. In the numerical analysis, it is shown that the Iosipescu specimens for different fiber orientations have to be modeled differently in order to closely approximate the true loading conditions. Correction factors are needed to allow for the nonuniformity of the strain field and the use of the average shear stress in the shear modulus evaluation. The correction factors, which are determined for the region occupied by the strain gage rosette, are found to be dependent upon the material orthotropic ratio and the finite element models. Based upon the experimental and numerical results, recommendations for improving the reliability and accuracy of the shear modulus values are made, and the implications for shear strength measurement discussed. Further application of the Iosipescu shear test to woven fabric composites is presented. The limitations of the traditional strain gage instrumentation on the satin weave and high tow plain weave fabrics is discussed. Test results of a epoxy based aluminum particulate composite is also presented. A modification of the Iosipescu specimen is proposed and investigated experimentally and numerically. It is shown that the proposed new specimen design provides a more uniform shear stress field in the test section and greatly reduces the normal and shear stress concentrations in the vicinity of the notches. While the fabrication and the material cost of the proposed specimen is tremendously reduced, it is shown the accuracy of the shear modulus measurement is not sacrificed.

Inelastic response of metal matrix composites under biaxial loading

NASA Technical Reports Server (NTRS)

Mirzadeh, F.; Pindera, Marek-Jerzy; Herakovich, Carl T.

1990-01-01

Elements of the analytical/experimental program to characterize the response of silicon carbide titanium (SCS-6/Ti-15-3) composite tubes under biaxial loading are outlined. The analytical program comprises prediction of initial yielding and subsequent inelastic response of unidirectional and angle-ply silicon carbide titanium tubes using a combined micromechanics approach and laminate analysis. The micromechanics approach is based on the method of cells model and has the capability of generating the effective thermomechanical response of metal matrix composites in the linear and inelastic region in the presence of temperature and time-dependent properties of the individual constituents and imperfect bonding on the initial yield surfaces and inelastic response of (0) and (+ or - 45)sub s SCS-6/Ti-15-3 laminates loaded by different combinations of stresses. The generated analytical predictions will be compared with the experimental results. The experimental program comprises generation of initial yield surfaces, subsequent stress-strain curves and determination of failure loads of the SCS-6/Ti-15-3 tubes under selected loading conditions. The results of the analytical investigation are employed to define the actual loading paths for the experimental program. A brief overview of the experimental methodology is given. This includes the test capabilities of the Composite Mechanics Laboratory at the University of Virginia, the SCS-6/Ti-15-3 composite tubes secured from McDonnell Douglas Corporation, a text fixture specifically developed for combined axial-torsional loading, and the MTS combined axial-torsion loader that will be employed in the actual testing.

Inflatable Launch and Recovery System

DTIC Science & Technology

2014-07-31

clamping fixture connects the ramp structure to the vessel. A snubber element dampens vibrations and transient tow loads. Unclassified Unclassified...integrated dynamic snubber element to dampen out vibrations and transient tow loads. The main air fill line from the handling system to the inflatable ramp...of the vessel A with standard container cam locks 12a (two of which are shown in phantom in FIG. 1). The system 10 can connect to a vessel power

An in-situ study in SEM of delamination in several graphite/epoxy composite material systems

NASA Technical Reports Server (NTRS)

Bradley, W. L.

1986-01-01

A three point bend fixture compatible with the current loading stage for the Scanning Electron Microscope was designed and fabricated. End-notched flexure tests were run on several materials. Work to date was on AS4/3502, T6T145/F155, and T6T145/F185. Fracture toughness was measured. Fracture of neat resin specimens was begun. The decrease in delaminatin fracture toughness, compared to neat resin toughness, due to rigid fiber filler and interlaminar failure is addressed. An experimental program was designed to try to determine the proper interpretatin for apparent microcracking in neat resin specimens.

The Effects of High Intensity Impulse Loading on Reinforced Concrete Beams.

DTIC Science & Technology

1976-06-01

bunker were buried in a shallow trench leading to an ^ J^^ uipment for the about 200 feet away This bunker ho!i!"daJ^ /^eler an3 pJe ?ure transducer...transducer was utilized in an effort to obtain more reliable pressure-time data. The test cJnf gSralion was further modified by burying the ^st fixture...Concluded) 5.i, ms PAQS IS QUALITY FRACtXCABLB mOgOOiPYfUKHlSUiiSrOODC ___ •■•I VCVINM ^ M < >• •*•••«• •» • Its’" ■ > ,1 I I • * ^ ; *.8 • • 81

High Temperature Ultrasonic Probe and Pulse-Echo Probe Mounting Fixture for Testing and Blind Alignment on Steam Pipes

NASA Technical Reports Server (NTRS)

Lih, Shyh-Shiuh (Inventor); Takano, Nobuyuki (Inventor); Lee, Hyeong Jae (Inventor); Bao, Xiaoqi (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Sherrit, Stewart (Inventor); Ostlund, Patrick N. (Inventor)

2017-01-01

A high temperature ultrasonic probe and a mounting fixture for attaching and aligning the probe to a steam pipe using blind alignment. The high temperature ultrasonic probe includes a piezoelectric transducer having a high temperature. The probe provides both transmitting and receiving functionality. The mounting fixture allows the high temperature ultrasonic probe to be accurately aligned to the bottom external surface of the steam pipe so that the presence of liquid water in the steam pipe can be monitored. The mounting fixture with a mounted high temperature ultrasonic probe are used to conduct health monitoring of steam pipes and to track the height of condensed water through the wall in real-time.

24 CFR 3280.607 - Plumbing fixtures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... less than 11/2 inches for sinks of two or more compartments, dishwashers, clothes washing machines... of Test for Safety Glazing Materials Used in Buildings, ANSI Z97.1-1984. (iv) Prefabricated plumbing fixtures shall be approved or listed. (4) Dishwashing machines. (i) A dishwashing machine shall not be...

24 CFR 3280.607 - Plumbing fixtures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... less than 11/2 inches for sinks of two or more compartments, dishwashers, clothes washing machines... of Test for Safety Glazing Materials Used in Buildings, ANSI Z97.1-1984. (iv) Prefabricated plumbing fixtures shall be approved or listed. (4) Dishwashing machines. (i) A dishwashing machine shall not be...

24 CFR 3280.607 - Plumbing fixtures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... less than 11/2 inches for sinks of two or more compartments, dishwashers, clothes washing machines... of Test for Safety Glazing Materials Used in Buildings, ANSI Z97.1-1984. (iv) Prefabricated plumbing fixtures shall be approved or listed. (4) Dishwashing machines. (i) A dishwashing machine shall not be...

24 CFR 3280.607 - Plumbing fixtures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... less than 11/2 inches for sinks of two or more compartments, dishwashers, clothes washing machines... of Test for Safety Glazing Materials Used in Buildings, ANSI Z97.1-1984. (iv) Prefabricated plumbing fixtures shall be approved or listed. (4) Dishwashing machines. (i) A dishwashing machine shall not be...

In-flight investigation of shuttle tile pressure orifice installations

NASA Technical Reports Server (NTRS)

Moes, Timothy R.; Meyer, Robert R., Jr.

1990-01-01

To determine shuttle orbiter wing loads during ascent, wing load instrumentation was added to Columbia (OV-102). This instrumentation included strain gages and pressure orifices on the wing. The loads derived from wing pressure measurements taken during STS 61-C did not agree with those derived from strain gage measurements or with the loads predicted from the aerodynamic database. Anomalies in the surface immediately surrounding the pressure orifices in the thermal protection system (TPS) tiles were one possible cause of errors in the loads derived from wing pressure measurements. These surface anomalies were caused by a ceramic filler material which was installed around the pressure tubing. The filler material allowed slight movement of the TPS tile and pressure tube as the airframe flexed and bent under aerodynamic loads during ascent and descent. Postflight inspection revealed that this filler material had protruded from or receeded beneath the surface, causing the orifice to lose its flushness. Flight tests were conducted at NASA Ames Research Center Dryden Flight Research Facility to determine the effects of any anomaly in surface flushness of the orifice installation on the measured pressures at Mach numbers between 0.6 and 1.4. An F-104 aircraft with a flight test fixture mounted beneath the fuselage was used for these flights. Surface flushness anomalies typical of those on the orbiter after flight (STA 61-C) were tested. Also, cases with excessive protrusion and recession of the filler material were tested. This report shows that the anomalies in STS 61-C orifice installations adversely affected the pressure measurements. But the magnitude of the affect was not great enough to account for the discrepancies with the strain gage measurements and the aerodynamic predictions.

Quality improvement program for the B83 bomb hand truck

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

Loll, M.B.; Buck, S.A.

1998-04-01

This report describes the problems, issues, and history of the H1347 bomb hand truck for the B83 bomb after the bomb was put into stockpile in the mid-1980s. Major issues that were reported in Unsatisfactory Reports (URs) were cracking problems on stacking fixture welds, cracked welds on the caster bracket receptacles on the cradle, cracked caster mounting brackets, casters unlocking from the swivel lock position, and caster tires rubbing and binding on the stacking frame. Resolution of these and other problems is described. The introduction of the H695B storage-only bomb hand truck to alleviate a shortage of bomb hand trucksmore » in the mid-1990s is described. The development and qualification of the H1347A bomb hand truck as a replacement for the H695 B is covered. The results from load test evaluations on the stacking fixture, cradle, and casters for the H1347 are described along with towing results on one and two-high stack configurations of B83 bombs in bomb hand trucks. New towing and truck/trailer transport procedures are described. Development, evaluation, and production recommendations for a stronger caster mounting bracket are described.« less

Shuttle antenna radome technology test program. Volume 2: Development of S-band antenna interface design

NASA Technical Reports Server (NTRS)

Kuhlman, E. A.; Baranowski, L. C.

1977-01-01

The effects of the Thermal Protection Subsystem (TPS) contamination on the space shuttle orbiter S band quad antenna due to multiple mission buildup are discussed. A test fixture was designed, fabricated and exposed to ten cycles of simulated ground and flight environments. Radiation pattern and impedance tests were performed to measure the effects of the contaminates. The degradation in antenna performance was attributed to the silicone waterproofing in the TPS tiles rather than exposure to the contaminating sources used in the test program. Validation of the accuracy of an analytical thermal model is discussed. Thermal vacuum tests with a test fixture and a representative S band quad antenna were conducted to evaluate the predictions of the analytical thermal model for two orbital heating conditions and entry from each orbit. The results show that the accuracy of predicting the test fixture thermal responses is largely dependent on the ability to define the boundary and ambient conditions. When the test conditions were accurately included in the analytical model, the predictions were in excellent agreement with measurements.

Porcelain Enamel Material Testing Procedures to Determine the Damping Properties and the Results of Selected Materials

DTIC Science & Technology

1980-09-01

AFWAL-TR-80-41 16 a N0946 6 6 PORCELAIN ENAMEL MATERIAL TESTING PROCEDURES TO DETERMINE THE DAMPINGi l PROPERTIES AND THE RESULTS OF ,= SELECTED...15..DECLASSI FtCATION/ DOWNGRADING SCHEDULE N.A(U~~~~ ~N A. 7~ ~&:’? 16 . DISThmBUTTUSTATEMENT (o1 this Report) Approved for public release...Damping Fixture 15 Number One 6 High Temperature Enamels Damping Fixture 16 Number Two 7 Schematic of the Enamels Testing Furnace Showing 18 the

Testing Fixture For Microwave Integrated Circuits

NASA Technical Reports Server (NTRS)

Romanofsky, Robert; Shalkhauser, Kurt

1989-01-01

Testing fixture facilitates radio-frequency characterization of microwave and millimeter-wave integrated circuits. Includes base onto which two cosine-tapered ridge waveguide-to-microstrip transitions fastened. Length and profile of taper determined analytically to provide maximum bandwidth and minimum insertion loss. Each cosine taper provides transformation from high impedance of waveguide to characteristic impedance of microstrip. Used in conjunction with automatic network analyzer to provide user with deembedded scattering parameters of device under test. Operates from 26.5 to 40.0 GHz, but operation extends to much higher frequencies.

Educational Attainment as Process: Using Hierarchical Discrete-Time Event History Analysis to Model Rate of Progress

ERIC Educational Resources Information Center

Bahr, Peter Riley

2009-01-01

Variables that address student enrollment patterns (e.g., persistence, enrollment inconsistency, completed credit hours, course credit load, course completion rate, procrastination) constitute a longstanding fixture of analytical strategies in educational research, particularly research that focuses on explaining variation in academic outcomes.…

In vitro validation of a novel mechanical model for testing the anchorage capacity of pedicle screws using physiological load application.

PubMed

Liebsch, Christian; Zimmermann, Julia; Graf, Nicolas; Schilling, Christoph; Wilke, Hans-Joachim; Kienle, Annette

2018-01-01

Biomechanical in vitro tests analysing screw loosening often include high standard deviations caused by high variabilities in bone mineral density and pedicle geometry, whereas standardized mechanical models made of PU foam often do not integrate anatomical or physiological boundary conditions. The purpose of this study was to develop a most realistic mechanical model for the standardized and reproducible testing of pedicle screws regarding the resistance against screw loosening and the holding force as well as to validate this model by in vitro experiments. The novel mechanical testing model represents all anatomical structures of a human vertebra and is consisting of PU foam to simulate cancellous bone, as well as a novel pedicle model made of short carbon fibre filled epoxy. Six monoaxial cannulated pedicle screws (Ø6.5 × 45mm) were tested using the mechanical testing model as well as human vertebra specimens by applying complex physiological cyclic loading (shear, tension, and bending; 5Hz testing frequency; sinusoidal pulsating forces) in a dynamic materials testing machine with stepwise increasing load after each 50.000 cycles (100.0N shear force + 20.0N per step, 51.0N tension force + 10.2N per step, 4.2Nm bending moment + 0.8Nm per step) until screw loosening was detected. The pedicle screw head was fixed on a firmly clamped rod while the load was applied in the vertebral body. For the in vitro experiments, six human lumbar vertebrae (L1-3, BMD 75.4 ± 4.0mg/cc HA, pedicle width 9.8 ± 0.6mm) were tested after implanting pedicle screws under X-ray control. Relative motions of pedicle screw, specimen fixture, and rod fixture were detected using an optical motion tracking system. Translational motions of the mechanical testing model experiments in the point of load introduction (0.9-2.2mm at 240N shear force) were reproducible within the variation range of the in vitro experiments (0.6-3.5mm at 240N shear force). Screw loosening occurred continuously in each case between 140N and 280N, while abrupt failures of the specimen were observed only in vitro. In the mechanical testing model, no translational motion was detected in the screw entry point, while in vitro, translational motions of up to 2.5mm in inferior direction were found, leading to a slight shift of the centre of rotation towards the screw tip. Translational motions of the screw tip of about 5mm in superior direction were observed both in vitro and in the mechanical testing model, while they were continuous in the mechanical testing model and rapidly increasing after screw loosening initiation in vitro. The overall pedicle screw loosening characteristics were qualitatively and quantitatively similar between the mechanical testing model and the human vertebral specimens as long as there was no translation of the screw at the screw entrance point. Therefore, the novel mechanical testing model represents a promising method for the standardized testing of pedicle screws regarding screw loosening for cases where the screw rotates around a point close to the screw entry point. Copyright © 2017 Elsevier Ltd. All rights reserved.

KSC-99pp1181

NASA Image and Video Library

1999-10-06

KENNEDY SPACE CENTER, FLA. -- NASA's Super Guppy airplane, with the International Space Station's (ISS) S1 truss aboard, rolls to a stop at KSC's Shuttle Landing Facility. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The Super Guppy, with its 25-foot diameter fuselage designed to handle oversized loads, is well prepared to transport the truss and other ISS segments. Loading the Guppy is easy because of the unique "fold-away" nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight. The truss is to be transferred to the Operations and Checkout Building

KSC-99pp1180

NASA Image and Video Library

1999-10-06

KENNEDY SPACE CENTER, FLA. -- NASA's Super Guppy airplane, with the International Space Station's (ISS) S1 truss aboard, arrives at KSC's Shuttle Landing Facility from Marshall Space Flight Center. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The Super Guppy, with its 25-foot diameter fuselage designed to handle oversized loads, is well prepared to transport the truss and other ISS segments. Loading the Guppy is easy because of the unique "fold-away" nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight. The truss is to be moved to the Operations and Checkout Building

KSC-99pp1182

NASA Image and Video Library

1999-10-07

KENNEDY SPACE CENTER, FLA. -- At KSC's Shuttle Landing Facility, NASA's Super Guppy opens to reveal its cargo, the International Space Station's (ISS) S1 truss. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The Super Guppy, with its 25-foot diameter fuselage designed to handle oversized loads, is well prepared to transport the truss and other ISS segments. Loading the Guppy is easy because of the unique "fold-away" nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight. The truss is to be transferred to the Operations and Checkout Building

KSC-99pp1185

NASA Image and Video Library

1999-10-07

KENNEDY SPACE CENTER, FLA. -- At the Shuttle Landing Facility, workers attach cranes to the S1 truss, a segment of the International Space Station, to lift the truss to a payload transporter for its transfer to the Operations and Checkout Building. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The truss arrived at KSC aboard NASA's Super Guppy, with a 25-foot diameter fuselage designed to handle oversized loads. Loading the Guppy is easy because of the unique "fold-away" nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight

KSC-99pp1183

NASA Image and Video Library

1999-10-07

KENNEDY SPACE CENTER, FLA. -- At the Shuttle Landing Facility, the newly arrived S1 truss, a segment of the International Space Station (ISS), is offloaded from NASA's Super Guppy aircraft. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The Super Guppy, with its 25-foot diameter fuselage designed to handle oversized loads, is well prepared to transport the truss and other ISS segments. Loading the Guppy is easy because of the unique "fold-away" nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight. The truss is being transferred to the Operations and Checkout Building

Micromotion and stress distribution of immediate loaded implants: a finite element analysis.

PubMed

Fazel, A; Aalai, S; Rismanchian, M; Sadr-Eshkevari, P

2009-12-01

Primary stability and micromotion of the implant fixture is mostly influenced by its macrodesign. To assess and compare the peri-implant stress distribution and micromotion of two types of immediate loading implants, immediate loaded screw (ILS) Nisastan and Xive (DENTSPLY/Friadent, Monnheim, Germany), and to determine the best macrodesign of these two implants by finite element analysis. In this experimental study, the accurate pictures of two fixtures (ILS: height = 13, diameter = 4 mm and Xive: height = 13, diameter = 3.8 mm) were taken by a new digital camera (Nikon Coolpix 5700 [Nikon, Japan], resolution = 5.24 megapixel, lens = 8x optical, 4x digital zoom). Following accurate measurements, the three-dimensional finite element computer model was simulated and inserted in simulated mandibular bone (D(2)) in SolidWorks 2003 (SolidWork Corp., MA, USA) and Ansys 7.1 (Ansys, Inc., Canonsburg, PA, USA). After loading (500 N, 75 degrees above horizon), the displacement was displayed and von Mises stress was recorded. It was found that the primary stability of ILS was greater (152 microm) than Xive (284 microm). ILS exhibited more favorable stress distribution. Maximum stress concentration found in periapical bone around Xive ( approximately 30 MPa) was lesser than Nisastan ( approximately 37 MPa). Macrodesign of ILS leads to better primary stability and stress distribution. Maximum stress around Xive was less.

10 CFR 429.54 - Metal halide lamp ballasts and fixtures.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Metal halide lamp ballasts and fixtures. 429.54 Section 429.54 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... and tested to ensure that: (i) Any represented value of estimated energy efficiency calculated as the...

10 CFR 429.54 - Metal halide lamp ballasts and fixtures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Metal halide lamp ballasts and fixtures. 429.54 Section 429.54 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... and tested to ensure that: (i) Any represented value of estimated energy efficiency calculated as the...

10 CFR 429.54 - Metal halide lamp ballasts and fixtures.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Metal halide lamp ballasts and fixtures. 429.54 Section 429.54 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION CERTIFICATION, COMPLIANCE, AND ENFORCEMENT FOR... and tested to ensure that: (i) Any represented value of estimated energy efficiency calculated as the...

KSC-99pp0229

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building's high bay, the Rotation Handling Fixture (RHF), with a simulated module attached, is lowered by crane into the altitude chamber below during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, depositing it into the altitude chamber for leak testing. The chamber was recently reactivated after a 24-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

KSC-99pp0230

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- Viewed from inside the altitude chamber in the Operations and Checkout Building's high bay, the Rotation Handling Fixture (RHF), with a simulated module attached, is lowered during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, depositing it into the altitude chamber for leak testing. The chamber was recently reactivated after a 24-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

KSC-99pp0228

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building's high bay, a crane lifts the Rotation Handling Fixture (RHF) and simulated module during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, lifting it up and into an altitude chamber for leak testing. The chamber was recently reactivated after a 24-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Experimental evaluation of tailored chordwise deformable box beam and correlation with theory

NASA Technical Reports Server (NTRS)

Rehfield, Lawrence W.; Zischka, Peter J.; Chang, Stephen; Fentress, Michael L.; Ambur, Damodar R.

1993-01-01

This paper describes an experimental methodology based upon the use of a flexible sling support and load application system that has been created and utilized to evaluate a box beam which incorporates an elastic tailoring technology. The design technique used here for elastically tailoring the composite box beam structure is to produce exaggerated chordwise camber deformation of substantial magnitude to be of practical use in the new composite aircraft wings. The traditional methods such as a four-point bend test to apply constant bending moment with rigid fixtures inhibits the designed chordwise deformation from occurring and, hence, the need for the new test method. The experimental results for global camber and spanwise bending compliances correlate well with theoretical predictions based on a beam-like model.

Conceptual design of modular fixture for frame welding and drilling process integration case study: Student chair in UNS industrial engineering integrated practicum

NASA Astrophysics Data System (ADS)

Darmawan, Tofiq Dwiki; Priadythama, Ilham; Herdiman, Lobes

2018-02-01

Welding and drilling are main processes of making chair frame from metal material. Commonly, chair frame construction includes many arcs which bring difficulties for its welding and drilling process. In UNS industrial engineering integrated practicum there are welding fixtures which use to fixing frame component position for welding purpose. In order to achieve exact holes position for assembling purpose, manual drilling processes were conducted after the frame was joined. Unfortunately, after it was welded the frame material become hard and increase drilling tools wear rate as well as reduce holes position accuracy. The previous welding fixture was not equipped with clamping system and cannot accommodate drilling process. To solve this problem, our idea is to reorder the drilling process so that it can be execute before welding. Thus, this research aims to propose conceptual design of modular fixture which can integrate welding and drilling process. We used Generic Product Development Process to address the design concept. We collected design requirements from 3 source, jig and fixture theoretical concepts, user requirements, and clamping part standards. From 2 alternatives fixture tables, we propose the first which equipped with mounting slots instead of holes. We test the concept by building a full sized prototype and test its works by conducting welding and drilling of a student chair frame. Result from the welding and drilling trials showed that the holes are on precise position after welding. Based on this result, we conclude that the concept can be a consideration for application in UNS Industrial Engineering Integrated Practicum.

Analysis of Nonlinear Insertion Loss of Hearing Protection Devices using an Acoustic Test Fixture

DTIC Science & Technology

2015-09-01

USAARL Report No. 2016-05 Analysis of Nonlinear Insertion Loss of Hearing Protection Devices using an Acoustic Test Fixture By Robert Williams1...through circuitry. Talk through circuits use electro- acoustic transducers to pass ambient sounds through the protector. When the circuitry detects...the SPL of the acoustic insult. If the protective capacity is variable, it should be accounted for in the selection of appropriate HPDs. REAT

A Portable Ultrasonic Nondestructive Inspection System for Metal Matrix Composite Track Shoes

NASA Astrophysics Data System (ADS)

Mi, Bao; Zhao, Xiaoliang; Qian, Tao; Stevenson, Mark; Kwan, Chiman; Owens, Steven E.; Royer, Roger L.; Tittmann, Bernhard R.; Raju, Basavaraju B.

2007-03-01

Cast aluminum track shoes reinforced with metal matrix composite (MMC) inserts at heavy loading areas such as center splines and sprocket windows are light in weight, and can resist high temperature and wear. Various defects such as disbonds at the insert-substrate interface, cracks and porosity in the MMC layer, etc. can be introduced during the manufacturing process and/or in service. This paper presents a portable ultrasonic system to automatically inspect tank track shoes for disbond. Ultrasonic pulse/echo inspection has shown good reliability for disbond detection. A prototype sensor array fixture has been designed and fabricated to prove the feasibility. Good agreements between the sensor fixture results and ultrasonic C-scan images were obtained.

Simulated Space Environmental Testing on Thin Films

NASA Technical Reports Server (NTRS)

Russell, Dennis A.; Fogdall, Larry B.; Bohnhoff-Hlavacek, Gail; Connell, John W. (Technical Monitor)

2000-01-01

An exploratory program has been conducted, to irradiate some mature commercial and some experimental polymer films with radiation simulating certain Earth orbits, and to obtain data about the response of each test film's reflective and tensile properties. Protocols to conduct optimized tests were considered and developed to a "prototype" level during this program. Fifteen polymer film specimens were arranged on a specially designed test fixture. The fixture featured controlled exposure areas, and protected the ends of the samples for later gripping in tensile tests. The fixture featured controlled exposure areas, and protected the ends of the samples for later gripping in tensile tests. The fixture containing the films was installed in a clean vacuum chamber where protons, electrons and solar ultraviolet (UV) radiation could simultaneously irradiate the specimens. Near realtime UV rates were used, whereas proton and electron rates were accelerated appreciably to simulate 5 years in orbit during a two month test. Periodically, the spectral reflectance of each film was measured in situ. After the end of the irradiation, final reflectance measurements were made in situ, and solar absorptance values were derived for each specimen. These samples were then measured in air for thermal emittance and for tensile strength. Most specimens withstood the irradiation intact, but with reduced reflectance (increased solar absorptance). Thermal emittance changed slightly in several materials, as did their tensile strength and elongation at break. Conclusions are drawn about the performance of the films. Simulated testing to an expected 5 year dose of electrons and protons consistent with those expected at L2 and 0.98 AU orbits and 100 equivalent solar hours exposure.

KSC-99pp1186

NASA Image and Video Library

1999-10-07

KENNEDY SPACE CENTER, FLA. -- Escort vehicles prepare to leave the Shuttle Landing Facility with the S1 truss (at right) on its trek to the Operations and Checkout Building. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The truss arrived at KSC aboard NASA's Super Guppy, seen in the background. The aircraft is uniquely built with a 25-foot diameter fuselage designed to handle oversized loads and a "fold-away" nose that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight

Brief, Why the Launch Equipment Test Facility Needs a Laser Tracker

NASA Technical Reports Server (NTRS)

Yue, Shiu H.

2011-01-01

The NASA Kennedy Space Center Launch Equipment Test Facility (LETF) supports a wide spectrum of testing and development activities. This capability was originally established in the 1970's to allow full-scale qualification of Space Shuttle umbilicals and T-O release mechanisms. The LETF has leveraged these unique test capabilities to evolve into a versatile test and development area that supports the entire spectrum of operational programs at KSC. These capabilities are historically Aerospace related, but can certainly can be adapted for other industries. One of the more unique test fixtures is the Vehicle Motion Simulator or the VMS. The VMS simulates all of the motions that a launch vehicle will experience from the time of its roll-out to the launch pad, through roughly the first X second of launch. The VMS enables the development and qualification testing of umbilical systems in both pre-launch and launch environments. The VMS can be used to verify operations procedures, clearances, disconnect systems performance &margins, and vehicle loads through processing flow motion excursions.

Fatigue loading and R-curve behavior of a dental glass-ceramic with multiple flaw distributions.

PubMed

Joshi, Gaurav V; Duan, Yuanyuan; Della Bona, Alvaro; Hill, Thomas J; St John, Kenneth; Griggs, Jason A

2013-11-01

To determine the effects of surface finish and mechanical loading on the rising toughness curve (R-curve) behavior of a fluorapatite glass-ceramic (IPS e.max ZirPress) and to determine a statistical model for fitting fatigue lifetime data with multiple flaw distributions. Rectangular beam specimens were fabricated by pressing. Two groups of specimens (n=30) with polished (15 μm) or air abraded surface were tested under rapid monotonic loading in oil. Additional polished specimens were subjected to cyclic loading at 2 Hz (n=44) and 10 Hz (n=36). All fatigue tests were performed using a fully articulated four-point flexure fixture in 37°C water. Fractography was used to determine the critical flaw size and estimate fracture toughness. To prove the presence of R-curve behavior, non-linear regression was used. Forward stepwise regression was performed to determine the effects on fracture toughness of different variables, such as initial flaw type, critical flaw size, critical flaw eccentricity, cycling frequency, peak load, and number of cycles. Fatigue lifetime data were fit to an exclusive flaw model. There was an increase in fracture toughness values with increasing critical flaw size for both loading methods (rapid monotonic loading and fatigue). The values for the fracture toughness ranged from 0.75 to 1.1 MPam(1/2) reaching a plateau at different critical flaw sizes based on loading method. Cyclic loading had a significant effect on the R-curve behavior. The fatigue lifetime distribution was dependent on the flaw distribution, and it fit well to an exclusive flaw model. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Fatigue loading and R-curve behavior of a dental glass-ceramic with multiple flaw distributions

PubMed Central

Joshi, Gaurav V.; Duan, Yuanyuan; Bona, Alvaro Della; Hill, Thomas J.; John, Kenneth St.; Griggs, Jason A.

2013-01-01

Objectives To determine the effects of surface finish and mechanical loading on the rising toughness curve (R-curve) behavior of a fluorapatite glass-ceramic (IPS e.max ZirPress) and to determine a statistical model for fitting fatigue lifetime data with multiple flaw distributions. Materials and Methods Rectangular beam specimens were fabricated by pressing. Two groups of specimens (n=30) with polished (15 μm) or air abraded surface were tested under rapid monotonic loading in oil. Additional polished specimens were subjected to cyclic loading at 2 Hz (n=44) and 10 Hz (n=36). All fatigue tests were performed using a fully articulated four-point flexure fixture in 37°C water. Fractography was used to determine the critical flaw size and estimate fracture toughness. To prove the presence of R-curve behavior, non-linear regression was used. Forward stepwise regression was performed to determine the effects on fracture toughness of different variables, such as initial flaw type, critical flaw size, critical flaw eccentricity, cycling frequency, peak load, and number of cycles. Fatigue lifetime data were fit to an exclusive flaw model. Results There was an increase in fracture toughness values with increasing critical flaw size for both loading methods (rapid monotonic loading and fatigue). The values for the fracture toughness ranged from 0.75 to 1.1 MPa·m1/2 reaching a plateau at different critical flaw sizes based on loading method. Significance Cyclic loading had a significant effect on the R-curve behavior. The fatigue lifetime distribution was dependent on the flaw distribution, and it fit well to an exclusive flaw model. PMID:24034441

Analysis of the stress state in an Iosipescu sheartest specimen

NASA Technical Reports Server (NTRS)

Walrath, D. E.; Adams, D. F.

1983-01-01

The state of stress in an Iosipescu shear test specimen is analyzed, utilizing a finite element computer program. The influence of test fixture configuration on this stress state is included. Variations of the standard specimen configuration, including notch depth, notch angle, and notch root radius are modeled. The purpose is to establish guidelines for a specimen geometry which will accommodate highly orthotropic materials while minimizing stress distribution nonuniformities. Materials ranging from isotropic to highly orthotropic are considered. An optimum specimen configuration is suggested, along with changes in the test fixture.

Modelling of eddy currents related to large angle magnetic suspension test fixture

NASA Technical Reports Server (NTRS)

Britcher, Colin P.; Foster, Lucas E.

1994-01-01

This report presents a preliminary analysis of the mathematical modelling of eddy current effects in a large-gap magnetic suspension system. It is shown that eddy currents can significantly affect the dynamic behavior and control of these systems, but are amenable to measurement and modelling. A theoretical framework is presented, together with a comparison of computed and experimental data related to the Large Angle Magnetic Suspension Test Fixture at NASA Langley Research Center.

Engine Load Path Calculations - Project Neo

NASA Technical Reports Server (NTRS)

Fisher, Joseph

2014-01-01

A mathematical model of the engine and actuator geometry was developed and used to perform a static force analysis of the system with the engine at different pitch and yaw angles. This analysis yielded the direction and magnitude of the reaction forces at the mounting points of the engine and actuators. These data were used to validate the selection of the actuators installed in the system and to design a new spherical joint to mount the engine on the test fixture. To illustrate the motion of the system and to further interest in the project, a functional 3D printed version of the system was made, featuring the full mobility of the real system.

Contribution a l'inspection automatique des pieces flexibles a l'etat libre sans gabarit de conformation

NASA Astrophysics Data System (ADS)

Sattarpanah Karganroudi, Sasan

The competitive industrial market demands manufacturing companies to provide the markets with a higher quality of production. The quality control department in industrial sectors verifies geometrical requirements of products with consistent tolerances. These requirements are presented in Geometric Dimensioning and Tolerancing (GD&T) standards. However, conventional measuring and dimensioning methods for manufactured parts are time-consuming and costly. Nowadays manual and tactile measuring methods have been replaced by Computer-Aided Inspection (CAI) methods. The CAI methods apply improvements in computational calculations and 3-D data acquisition devices (scanners) to compare the scan mesh of manufactured parts with the Computer-Aided Design (CAD) model. Metrology standards, such as ASME-Y14.5 and ISO-GPS, require implementing the inspection in free-state, wherein the part is only under its weight. Non-rigid parts are exempted from the free-state inspection rule because of their significant geometrical deviation in a free-state with respect to the tolerances. Despite the developments in CAI methods, inspection of non-rigid parts still remains a serious challenge. Conventional inspection methods apply complex fixtures for non-rigid parts to retrieve the functional shape of these parts on physical fixtures; however, the fabrication and setup of these fixtures are sophisticated and expensive. The cost of fixtures has doubled since the client and manufacturing sectors require repetitive and independent inspection fixtures. To eliminate the need for costly and time-consuming inspection fixtures, fixtureless inspection methods of non-rigid parts based on CAI methods have been developed. These methods aim at distinguishing flexible deformations of parts in a free-state from defects. Fixtureless inspection methods are required to be automatic, reliable, reasonably accurate and repeatable for non-rigid parts with complex shapes. The scan model, which is acquired as point clouds, represent the shape of a part in a free-state. Afterward, the inspection of defects is performed by comparing the scan and CAD models, but these models are presented in different coordinate systems. Indeed, the scan model is presented in the measurement coordinate system whereas the CAD model is introduced in the designed coordinate system. To accomplish the inspection and facilitate an accurate comparison between the models, the registration process is required to align the scan and CAD models in a common coordinate system. The registration includes a virtual compensation for the flexible deformation of the parts in a free-state. Then, the inspection is implemented as a geometrical comparison between the CAD and scan models. This thesis focuses on developing automatic and accurate fixtureless CAI methods for non-rigid parts along with assessing the robustness of the methods. To this end, an automatic fixtureless CAI method for non-rigid parts based on filtering registration points is developed to identify and quantify defects more accurately on the surface of scan models. The flexible deformation of parts in a free-state in our developed automatic fixtureless CAI method is compensated by applying FE non-rigid Registration (FENR) to deform the CAD model towards the scan mesh. The displacement boundary conditions (BCs) for FENR are determined based on the corresponding sample points, which are generated by the Generalized Numerical Inspection Fixture (GNIF) method on the CAD and scan models. These corresponding sample points are evenly distributed on the surface of the models. The comparison between this deformed CAD model and the scan mesh intend to evaluate and quantify the defects on the scan model. However, some sample points can be located close or on defect areas which result in an inaccurate estimation of defects. These sample points are automatically filtered out in our CAI method based on curvature and von Mises stress criteria. Once filtered out, the remaining sample points are used in a new FENR, which allows an accurate evaluation of defects with respect to the tolerances. The performance and robustness of all CAI methods are generally required to be assessed with respect to the actual measurements. This thesis also introduces a new validation metric for Verification and Validation (V&V) of CAI methods based on ASME recommendations. The developed V&V approach uses a nonparametric statistical hypothesis test, namely the Kolmogorov-Smirnov (K-S) test. In addition to validating the defects size, the K-S test allows a deeper evaluation based on distance distribution of defects. The robustness of CAI method with respect to uncertainties such as scanning noise is quantitatively assessed using the developed validation metric. Due to the compliance of non-rigid parts, a geometrically deviated part can still be assembled in the assembly-state. This thesis also presents a fixtureless CAI method for geometrically deviated (presenting defects) non-rigid parts to evaluate the feasibility of mounting these parts in the functional assembly-state. Our developed Virtual Mounting Assembly-State Inspection (VMASI) method performs a non-rigid registration to virtually mount the scan mesh in assembly-state. To this end, the point clouds of scan model representing the part in a free-state is deformed to meet the assembly constraints such as fixation position (e.g. mounting holes). In some cases, the functional shape of a deviated part can be retrieved by applying assembly loads, which are limited to permissible loads, on the surface of the part. The required assembly loads are estimated through our developed Restraining Pressures Optimization (RPO) aiming at displacing the deviated scan model to achieve the tolerance for mounting holes. Therefore, the deviated scan model can be assembled if the mounting holes on the predicted functional shape of scan model attain the tolerance range. Different industrial parts are used to evaluate the performance of our developed methods in this thesis. The automatic inspection for identifying different types of small (local) and big (global) defects on the parts results in an accurate evaluation of defects. The robustness of this inspection method is also validated with respect to different levels of scanning noise, which shows promising results. Meanwhile, the VMASI method is performed on various parts with different types of defects, which concludes that in some cases the functional shape of deviated parts can be retrieved by mounting them on a virtual fixture in assembly-state under restraining loads.

Structural Qualification Testing of the WindSat Payload Using Sine Bursts Near Structural Resonance

NASA Technical Reports Server (NTRS)

Pontius, Jim; Barnes, Donald; Broduer, Steve (Technical Monitor)

2001-01-01

Sine burst tests are often used for structural qualification of space flight hardware. In most instances, the driving frequency of the shaker is specified far below the structure's first resonant mode, such that the entire test article sees uniform acceleration. For large structures, this limits qualification testing to lower parts of the structure, or else it over-tests the lower structure to achieve qualification of the upper structure. The WindSat payload, a 10.5 foot tall graphite/epoxy, titanium, and aluminum radiometer, experiences accelerations at the six foot diameter reflector nearly four times that at the spacecraft interface. Due to size of the payload, the number of bonded joints, and the lightweight reflector support structure design and construction, using static pull testing to qualify all of the bonded joints in the upper structure would result in large, expensive, and extensive test fixturing. Sine burst testing near the first two structural resonant modes was performed on the WindSat payload to achieve the correct load factor distribution up the stack for structural qualification. In this presentation, how finite element method (FEM) sine burst predictions were used in conjunction with low level random and sine burst tests to achieve correct qualification test load factor distribution on the WindSat payload is discussed. Also presented is the risk mitigation approach for using the uncorrelated FEM in this procedure.

Application of High-Temperature Extrinsic Fabry-Perot Interferometer Strain Sensor

NASA Technical Reports Server (NTRS)

Piazza, Anthony

2008-01-01

In this presentation to the NASA Aeronautics Sensor Working Group the application of a strain sensor is outlined. The high-temperature extrinsic Fabry-Perot interferometer (EFPI) strain sensor was developed due to a need for robust strain sensors that operate accurately and reliably beyond 1800 F. Specifically, the new strain sensor would provide data for validating finite element models and thermal-structural analyses. Sensor attachment techniques were also developed to improve methods of handling and protecting the fragile sensors during the harsh installation process. It was determined that thermal sprayed attachments are preferable even though cements are simpler to apply as cements are more prone to bond failure and are often corrosive. Previous thermal/mechanical cantilever beam testing of EFPI yielded very little change to 1200 F, with excellent correlation with SG to 550 F. Current combined thermal/mechanical loading for sensitivity testing is accomplished by a furnace/cantilever beam loading system. Dilatometer testing has can also be used in sensor characterization to evaluate bond integrity, evaluate sensitivity and accuracy and to evaluate sensor-to-sensor scatter, repeatability, hysteresis and drift. Future fiber optic testing will examine single-mode silica EFPIs in a combined thermal/mechanical load fixture on C-C and C-SiC substrates, develop a multi-mode Sapphire strain-sensor, test and evaluate high-temperature fiber Bragg Gratings for use as strain and temperature sensors and attach and evaluate a high-temperature heat flux gauge.

Third Day of Loading Equipment for the Orion Recovery.

NASA Image and Video Library

2014-11-19

The Orion crew module recovery fixture is being loaded into the well deck of the USS Anchorage at Naval Base San Diego in California. The equipment will be used during recovery of the Orion crew module after its first flight test. Before launch of Orion on a Delta IV Heavy rocket from Cape Canaveral Air Force Station in Florida, NASA, Lockheed Martin and U.S. Navy personnel will head out to sea in the USS Anchorage and the USNS Salvor, a salvage ship, and wait for splashdown of the Orion crew module in the Pacific Ocean. The Ground Systems Development and Operations Program will lead the recovery efforts. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted flight test of Orion is scheduled to launch in December atop a United Launch Alliance Delta IV Heavy rocket and in 2018 on NASA’s Space Launch System rocket.

Third Day of Loading Equipment for the Orion Recovery.

NASA Image and Video Library

2014-11-19

The Orion crew module recovery fixture has been loaded into the well deck of the USS Anchorage at Naval Base San Diego in California. The equipment will be used during recovery of the Orion crew module after its first flight test. Before launch of Orion on a Delta IV Heavy rocket from Cape Canaveral Air Force Station in Florida, NASA, Lockheed Martin and U.S. Navy personnel will head out to sea in the USS Anchorage and the USNS Salvor, a salvage ship, and wait for splashdown of the Orion crew module in the Pacific Ocean. The Ground Systems Development and Operations Program will lead the recovery efforts. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted flight test of Orion is scheduled to launch in December atop a United Launch Alliance Delta IV Heavy rocket and in 2018 on NASA’s Space Launch System rocket.

Third Day of Loading Equipment for the Orion Recovery.

NASA Image and Video Library

2014-11-19

The Orion crew module recovery fixture and other ground support equipment have been loaded into the well deck of the USS Anchorage at Naval Base San Diego in California. The equipment will be used during recovery of the Orion crew module after its first flight test. Before launch of Orion on a Delta IV Heavy rocket from Cape Canaveral Air Force Station in Florida, NASA, Lockheed Martin and U.S. Navy personnel will head out to sea in the USS Anchorage and the USNS Salvor, a salvage ship, and wait for splashdown of the Orion crew module in the Pacific Ocean. The Ground Systems Development and Operations Program will lead the recovery efforts. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted flight test of Orion is scheduled to launch in December atop a United Launch Alliance Delta IV Heavy rocket and in 2018 on NASA’s Space Launch System rocket.

Transportation and handling loads

NASA Technical Reports Server (NTRS)

Ostrem, F. E.

1971-01-01

Criteria and recommended practices are presented for the prediction and verification of transportation and handling loads for the space vehicle structure and for monitoring these loads during transportation and handling of the vehicle or major vehicle segments. Elements of the transportation and handling systems, and the forcing functions and associated loads are described. The forcing functions for common carriers and typical handling devices are assessed, and emphasis is given to the assessment of loads at the points where the space vehicle is supported during transportation and handling. Factors which must be considered when predicting the loads include the transportation and handling medium; type of handling fixture; transport vehicle speed; types of terrain; weather (changes in pressure of temperature, wind, etc.); and dynamics of the transportation modes or handling devices (acceleration, deceleration, and rotations of the transporter or handling device).

Landing impact studies of a 0.3-scale model air cushion landing system for a Navy fighter airplane

NASA Technical Reports Server (NTRS)

Leland, T. J. W.; Thompson, W. C.

1975-01-01

An experimental study was conducted in order to determine the landing-impact behavior of a 0.3-scale, dynamically (but not physically) similar model of a high-density Navy fighter equipped with an air cushion landing system. The model was tested over a range of landing contact attitudes at high forward speeds and sink rates on a specialized test fixture at the Langley aircraft landing loads and traction facility. The investigation indicated that vertical acceleration at landing impact was highly dependent on the pitch angle at ground contact, the higher acceleration of approximately 5g occurring near zero body-pitch attitude. A limited number of low-speed taxi tests were made in order to determine model stability characteristics. The model was found to have good pitch-damping characteristics but stability in roll was marginal.

Nickel hydrogen cell tests. [recharging

NASA Technical Reports Server (NTRS)

Mueller, V. C.

1981-01-01

Some parametric tests followed by cycling tests are described for the characterization of the service life of nickel hydrogen cells. Three cells were automatically cycled in simulated low Earth orbit in 35 minute discharge, 55 minute charge, with charging voltage limited, temperature compensated. The cells were mounted in a fixture that conducts heat to an aluminum baseplate. The baseplate in turn, is bounded in a temperature controlled bath to remove the heat from the mounted fixture. One cell was tested with a zircar separator, which failed after 2473 cyles. Two other cells were tested one with a zircar separator; the other with asbestos. More than 400 cycles were achieved.

Spacecraft utensil/hand cleansing fixture

NASA Technical Reports Server (NTRS)

Jonkoniec, T. G.

1978-01-01

A fixture which provides a means for a crewman to perform, in zero gravity, laboratory utensil/tool cleansing and personal hygiene functions such as handwashing, shaving, body wash, and teeth brushing is described. A prototype unit developed incorporating design improvements resulting from breadboard tests in a one gravity and zero gravity environment demonstrated the capability of performing the different cleansing functions.

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System.

PubMed

Sim, Bo Kyun; Kim, Bongju; Kim, Min Jeong; Jeong, Guk Hyun; Ju, Kyung Won; Shin, Yoo Jin; Kim, Man Yong; Lee, Jong-Ho

2017-01-01

The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access hole for easy retrieval. This study aimed to introduce this modified design of the abutment screw, the concept of easy retrieval, and to compare the mechanical strengths of the conventional and hollow abutment screws by finite element analysis (FEA) and mechanical test. In the FEA results, both types of abutment screws showed similar stress distribution in the single artificial tooth system. A maximum load difference of about 2% occurred in the vertical load by a mechanical test. This study showed that the hollow abutment screw may be an alternative to the conventional abutment screws because this is designed for easy retrieval and that both abutment screws showed no significant difference in the mechanical tests and in the FEA.

KSC-99pp0231

NASA Image and Video Library

1999-02-23

KENNEDY SPACE CENTER, FLA. -- In the Operations and Checkout Building's high bay, the Rotation Handling Fixture (RHF), with a simulated module attached, is viewed from above the altitude chamber into which it was lowered during a test. Under normal operation, the RHF will hold a pressurized module intended for the International Space Station, depositing it into the altitude chamber for leak testing. The chamber was recently reactivated after a 20-year hiatus. Originally, two chambers were built to test Apollo Program flight hardware. They were last used in 1975 during the Apollo-Soyuz Test Project. In 1997, in order to increase the probability of successful missions aboard the ISS, NASA decided to perform leak tests on ISS pressurized modules at the launch site. After installation of new vacuum pumping equipment and controls, a new control room, and a new rotation and handling fixture, the chamber again became operational in February 1999. The chamber, which is 33 feet in diameter and 50 feet tall, is constructed of stainless steel. The rotation handling fixture is aluminum. The first module that will be tested for leaks is the U.S. Laboratory. No date has been determined for the test

Basic antenna transmitting characteristics using an extrapolation range measurement technique at a millimeter-wave band at NMIJ/AIST.

PubMed

Yamamoto, Tetsuya

2007-06-01

A novel test fixture operating at a millimeter-wave band using an extrapolation range measurement technique was developed at the National Metrology Institute of Japan (NMIJ). Here I describe the measurement system using a Q-band test fixture. I measured the relative insertion loss as a function of antenna separation distance and observed the effects of multiple reflections between the antennas. I also evaluated the antenna gain at 33 GHz using the extrapolation technique.

Apparatus for Testing Flat Specimens of Thermal Insulation

NASA Technical Reports Server (NTRS)

Fesmire, James E.; Augustynowicz, Stanislaw D.

2005-01-01

An apparatus has been developed to implement an improved method of testing flat-plate specimens of thermal-insulation materials for cryogenic application. The method includes testing under realistic use conditions that could include vacuum and mechanical loading at a pressure up to 70 psi (=0.48 MPa). The apparatus can accommodate a rigid or flexible specimen having thickness up to 1.25 in. (=3.2 cm) and diameters between 6 and 10 in. (about 15.2 and 25.4 cm, respectively). Typical test conditions include boundary temperatures between 77 K and 373 K and vacuum/interstitial gas filling at a pressure between 10(exp -6) torr (=1.3 x 10(exp -4) Pa) and 760 torr (atmospheric pressure =0.1 MPa). The interstitial gas could be N2, He, CO2, or any other suitable gas to which the insulation is expected to be exposed in use. Relative to prior apparatuses and testing methods, this apparatus and the testing method that it implements offer advantages of relative simplicity and ease of use. The basic principle of operation of the apparatus is that of boil-off calorimetry, using liquid nitrogen or any other suitable liquid that boils at a desired temperature below ambient temperature. Comparative rates of flow of heat through the thicknesses of the specimens (heat-leak rates) and apparent-thermal-conductivity values are obtained from tests of specimens. Absolute values of heat-leak rates and apparent thermal conductivities are computed from a combination of (1) the aforementioned comparative values and (2) calibration factors obtained by testing reference specimens of materials that have known thermal-insulation properties. The apparatus includes a full complement of temperature sensors, a vacuum pump and chamber, a monitoring and control system, and tools and fixtures that enable rapid and reliable installation and removal of specimens. A specimen is installed at the bottom of the vacuum chamber, and a cold-mass assembly that includes a tank is lowered into position above and around the specimen (see figure). A spring-based compensating fixture helps to ensure adequate thermal contact with possibly irregular specimen surfaces. For a high-compression test, the springs can be replaced with spacers. A flat circular load cell at the bottom of the chamber measures the compressive load on the specimen. Once the desired compressive-load, temperature, and vacuum/gas-filling conditions are established, testing begins. During a test, all measurements are recorded by use of a portable data-acquisition system and a computer. The total heat-leak rate is measured and calculated as the boil-off flow rate multiplied by the latent heat of vaporization. The parasitic heat leak (to the side of the specimen and to the top and side of the cold-mass tank) is reduced to a small fraction of the total heat leak by use of a combination of multilayer-insulation (MLI) shield rings, reflective film, a fiberglass/epoxy centering ring, and a bulk fill of aerogel beads. This combination eliminates the need for a cryogenic guard chamber used in a typical prior apparatus to reduce the parasitic heat leak.

KSC-99pp1184

NASA Image and Video Library

1999-10-07

KENNEDY SPACE CENTER, FLA. -- At the Shuttle Landing Facility, the S1 truss, a segment of the International Space Station, is moved away from the Super Guppy that brought it to KSC from Marshall Space Flight Center. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the ISS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communications systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The Super Guppy, with its 25-foot diameter fuselage designed to handle oversized loads, is well prepared to transport the truss and other ISS segments. Loading the Guppy is easy because of the unique "fold-away" nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an electric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight. The truss is being transferred to the Operations and Checkout Building

STS-112 S1 Truss Payload arrives at KSC

NASA Technical Reports Server (NTRS)

1999-01-01

KENNEDY SPACE CENTER, FLA. -- NASA's Super Guppy airplane, with the International Space Station's (ISS) S1 truss aboard, rolls to a stop at KSC's Shuttle Landing Facility. Manufactured by the Boeing Co. in Huntington Beach, Calif., this component of the I SS is the first starboard (right-side) truss segment, whose main job is providing structural support for the orbiting research facility's radiator panels that cool the Space Station's complex power system. The S1 truss segment also will house communicatio ns systems, external experiment positions and other subsystems. Primarily constructed of aluminum, the truss segment is 45 feet long, 15 feet wide and 6 feet tall. When fully outfitted, it will weigh 31,137 pounds. The truss is slated for flight in 2001. The Super Guppy, with its 25-foot diameter fuselage designed to handle oversized loads, is well prepared to transport the truss and other ISS segments. Loading the Guppy is easy because of the unique 'fold-away' nose of the aircraft that opens 110 degrees for cargo loading. A system of rails in the cargo compartment, used with either Guppy pallets or fixtures designed for specific cargo, makes cargo loading simple and efficient. Rollers mounted in the rails allow pallets or fixtures to be moved by an elec tric winch mounted beneath the cargo floor. Automatic hydraulic lock pins in each rail secure the pallet for flight. The truss is to be transferred to the Operations and Checkout Building

Industrial approach to piezoelectric damping of large fighter aircraft components

NASA Astrophysics Data System (ADS)

Simpson, John; Schweiger, Johannes

1998-06-01

Different concepts to damp structural vibrations of the vertical tail of fighter aircraft are reported. The various requirements for a vertical tail bias an integrated approach for the design. Several active vibrations suppression concepts had been investigated during the preparatory phase of a research program shared by Daimler-Benz Aerospace Military Aircraft (Dasa), Daimler-Benz Forschung (DBF) and Deutsche Forschungsandstalt fuer Luftund Raumfahrt (DLR). Now in the main phase of the programme, four concepts were finally chosen: two concepts with aerodynamic control surfaces and two concepts with piezoelectric components. One piezo concept approach will be described rigorously, the other concepts are briefly addressed. In the Dasa concept, thin surface piezo actuators are set out carefully to flatten the dynamic portion of the combined static and dynamic maximum bending moment loading case directly in the shell structure. The second piezo concept by DLR involves pre-loaded lead zirconate titanate (PZT)-block actuators at host structure fixtures. To this end a research apparatus was designed and built as a full scale simplified fin box with carbon fiber reinformed plastic skins and an aluminium stringer-rib substructure restrained by relevant aircraft fixtures. It constitutes a benchmark 3D-structural impedance. The engineering design incorporates 7kg of PZT surface actuators. The structural system then should be excited to more than 15mm tip displacement amplitude. This prepares the final step to total A/C integration. Typical analysis methods using cyclic thermal analogies adapted to induced load levels are compared. Commercial approaches leading onto basic state space model interpretation wrt. actuator sizing and positioning, structural integrity constraints, FE-validation and testing are described. Both piezoelectric strategies are aimed at straight open-loop performance related to concept weight penalty and input electric power. The required actuators, power and integration are then enhanced to specification standards. An adapted qualification program plan is used to improve analytical read across, specifications, manufacturing decisions, handling requirements. The next research goals are outlined.

Simulated Service and Stress Corrosion Cracking Testing for Friction Stir Welded Spun Form Domes

NASA Technical Reports Server (NTRS)

Stewart, Thomas J.; Torres, Pablo D.; Caratus, Andrei A.; Curreri, Peter A.

2010-01-01

Damage tolerance testing development was required to help qualify a new spin forming dome fabrication process for the Ares 1 program at Marshall Space Flight Center (MSFC). One challenge of the testing was due to the compound curvature of the dome. The testing was developed on a sub-scale dome with a diameter of approximately 40 inches. The simulated service testing performed was based on the EQTP1102 Rev L 2195 Aluminum Lot Acceptance Simulated Service Test and Analysis Procedure generated by Lockheed Martin for the Space Shuttle External Fuel Tank. This testing is performed on a specimen with an induced flaw of elliptical shape generated by Electrical Discharge Machining (EDM) and subsequent fatigue cycling for crack propagation to a predetermined length and depth. The specimen is then loaded in tension at a constant rate of displacement at room temperature until fracture occurs while recording load and strain. An identical specimen with a similar flaw is then proof tested at room temperature to imminent failure based on the critical offset strain achieved by the previous fracture test. If the specimen survives the proof, it is then subjected to cryogenic cycling with loads that are a percentage of the proof load performed at room temperature. If all cryogenic cycles are successful, the specimen is loaded in tension to failure at the end of the test. This standard was generated for flat plate, so a method of translating this to a specimen of compound curvature was required. This was accomplished by fabricating a fixture that maintained the curvature of the specimen rigidly with the exception of approximately one-half inch in the center of the specimen containing the induced flaw. This in conjunction with placing the center of the specimen in the center of the load train allowed for successful testing with a minimal amount of bending introduced into the system. Stress corrosion cracking (SCC) tests were performed using the typical double beam assembly and with 4-point loaded specimens under alternate immersion conditions in a 3.5% NaCl environment for 90 days. In addition, experiments were conducted to determine the threshold stress intensity factor for SCC (K1SCC) of Al-Li 2195 which to our knowledge has not been determined previously. The successful simulated service and stress corrosion testing helped to provide confidence to continue to Ares 1 scale dome fabrication.

Processor and method for developing a set of admissible fixture designs for a workpiece

DOEpatents

Brost, R.C.; Goldberg, K.Y.; Wallack, A.S.; Canny, J.

1996-08-13

A fixture process and method is provided for developing a complete set of all admissible fixture designs for a workpiece which prevents the workpiece from translating or rotating. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vice is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs. 27 figs.

Processor and method for developing a set of admissible fixture designs for a workpiece

DOEpatents

Brost, Randolph C.; Goldberg, Kenneth Y.; Wallack, Aaron S.; Canny, John

1996-01-01

A fixture process and method is provided for developing a complete set of all admissible fixture designs for a workpiece which prevents the workpiece from translating or rotating. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vice is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs.

KSC-2012-6430

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to lift a special fixture inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6447

NASA Image and Video Library

2012-12-06

CAPE CANAVERAL, Fla. – Technicians lift a special fixture inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6428

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to lift a special fixture inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6429

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to lift a special fixture inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6446

NASA Image and Video Library

2012-12-06

CAPE CANAVERAL, Fla. – Technicians lift a special fixture inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6445

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians lift a special fixture inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

Heat Bonding of Irradiated Ethylene Vinyl Acetate

NASA Technical Reports Server (NTRS)

Slack, D. H.

1986-01-01

Reliable method now available for joining parts of this difficult-tobond material. Heating fixture encircles ethylene vinyl acetate multiplesocket part, providing heat to it and to tubes inserted in it. Fixtures specially designed to match parts to be bonded. Tube-and-socket bonds made with this technique subjected to tensile tests. Bond strengths of 50 percent that of base material obtained consistently.

Fixture for holding testing transducer

DOEpatents

Wagner, T.A.; Engel, H.P.

A fixture for mounting an ultrasonic transducer against the end of a threaded bolt or stud to test the same for flaws. A base means threadedly secured to the side of the bolt has a rotating ring thereon. A post rising up from the ring (parallel to the axis of the workpiece) pivotally mounts a variable length cross arm, on the inner end of which is mounted the transducer. A spring means acts between the cross arm and the base to apply the testing transducer against the workpiece at a constant pressure. The device maintains constant for successive tests the radial and circumferential positions of the testing transducer and its contact pressure against the end of the workpiece.

Fixture for holding testing transducer

DOEpatents

Wagner, Thomas A.; Engel, Herbert P.

1984-01-01

A fixture for mounting an ultrasonic transducer against the end of a threaded bolt or stud to test the same for flaws. A base means threadedly secured to the side of the bolt has a rotating ring thereon. A post rising up from the ring (parallel to the axis of the workpiece) pivotally mounts a variable length cross arm, on the inner end of which is mounted the transducer. A spring means acts between the cross arm and the base to apply the testing transducer against the workpiece at a constant pressure. The device maintains constant for successive tests the radial and circumferential positions of the testing transducer and its contact pressure against the end of the workpiece.

NASA Enterprise Visual Analysis

NASA Technical Reports Server (NTRS)

Lopez-Tellado, Maria; DiSanto, Brenda; Humeniuk, Robert; Bard, Richard, Jr.; Little, Mia; Edwards, Robert; Ma, Tien-Chi; Hollifield, Kenneith; White, Chuck

2007-01-01

NASA Enterprise Visual Analysis (NEVA) is a computer program undergoing development as a successor to Launch Services Analysis Tool (LSAT), formerly known as Payload Carrier Analysis Tool (PCAT). NEVA facilitates analyses of proposed configurations of payloads and packing fixtures (e.g. pallets) in a space shuttle payload bay for transport to the International Space Station. NEVA reduces the need to use physical models, mockups, and full-scale ground support equipment in performing such analyses. Using NEVA, one can take account of such diverse considerations as those of weight distribution, geometry, collision avoidance, power requirements, thermal loads, and mechanical loads.

NASA Dryden's new in-house designed Propulsion Flight Test Fixture (PFTF), carried on an F-15B's cen

NASA Technical Reports Server (NTRS)

2001-01-01

NASA Dryden Flight Research Center's new in-house designed Propulsion Flight Test Fixture (PFTF) is an airborne engine test facility that allows engineers to glean actual flight data on small experimental engines that would otherwise have to be gathered from traditional wind tunnels, ground test stands or laboratory setups. Now, with the 'captive carry' capability of the PFTF, new air-breathing propulsion schemes, such as Rocket Based Combined Cycle engines, can be economically flight-tested using sub-scale experiments. The PFTF flew mated to NASA Dryden's specially-equipped supersonic F-15B research aircraft during December 2001 and January 2002. The PFTF, carried on the F-15B's centerline attachment point, underwent in-flight checkout, known as flight envelope expansion, in order to verify its design and capabilities. Envelope expansion for the PFTF included envelope clearance, which involves maximum performance testing. Top speed of the F-15B with the PFTF is Mach 2.0. Other elements of envelope clearance are flying qualities assessment and flutter analysis. Airflow visualization of the PFTF and a 'stand-in' test engine was accomplished by attaching small tufts of nylon on them and videotaping the flow patterns revealed during flight. A surrogate experimental engine shape, called the cone tube, was flown attached to the force balance on the PFTF. The cone tube emulated the dimensional and mass properties of the maximum design load the PFTF can carry. As the F-15B put the PFTF and the attached cone tube through its paces, accurate data was garnered, allowing engineers to fully verify PFTF and force balance capabilities in real flight conditions. When the first actual experimental engine is ready to fly on the F-15B/PFTF, engineers will have full confidence and knowledge of what they can accomplish with this 'flying engine test stand.'

NASA Dryden's new in-house designed Propulsion Flight Test Fixture (PFTF) flew mated to a specially-

NASA Technical Reports Server (NTRS)

2001-01-01

NASA Dryden Flight Research Center's new in-house designed Propulsion Flight Test Fixture (PFTF) is an airborne engine test facility that allows engineers to glean actual flight data on small experimental engines that would otherwise have to be gathered from traditional wind tunnels, ground test stands or laboratory setups. Now, with the 'captive carry' capability of the PFTF, new air-breathing propulsion schemes, such as Rocket Based Combined Cycle engines, can be economically flight-tested using sub-scale experiments. The PFTF flew mated to NASA Dryden's specially-equipped supersonic F-15B research aircraft during December 2001 and January 2002. The PFTF, carried on the F-15B's centerline attachment point, underwent in-flight checkout, known as flight envelope expansion, in order to verify its design and capabilities. Envelope expansion for the PFTF included envelope clearance, which involves maximum performance testing. Top speed of the F-15B with the PFTF is Mach 2.0. Other elements of envelope clearance are flying qualities assessment and flutter analysis. Airflow visualization of the PFTF and a 'stand-in' test engine was accomplished by attaching small tufts of nylon on them and videotaping the flow patterns revealed during flight. A surrogate experimental engine shape, called the cone tube, was flown attached to the force balance on the PFTF. The cone tube emulated the dimensional and mass properties of the maximum design load the PFTF can carry. As the F-15B put the PFTF and the attached cone tube through its paces, accurate data was garnered, allowing engineers to fully verify PFTF and force balance capabilities in real flight conditions. When the first actual experimental engine is ready to fly on the F-15B/PFTF, engineers will have full confidence and knowledge of what they can accomplish with this 'flying engine test stand.'

Processor and method for developing a set of admissible fixture designs for a workpiece

DOEpatents

Brost, Randolph C.; Goldberg, Kenneth Y.; Canny, John; Wallack, Aaron S.

1999-01-01

Methods and apparatus are provided for developing a complete set of all admissible Type I and Type II fixture designs for a workpiece. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vise is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs.

Processor and method for developing a set of admissible fixture designs for a workpiece

DOEpatents

Brost, R.C.; Goldberg, K.Y.; Canny, J.; Wallack, A.S.

1999-01-05

Methods and apparatus are provided for developing a complete set of all admissible Type 1 and Type 2 fixture designs for a workpiece. The fixture processor generates the set of all admissible designs based on geometric access constraints and expected applied forces on the workpiece. For instance, the fixture processor may generate a set of admissible fixture designs for first, second and third locators placed in an array of holes on a fixture plate and a translating clamp attached to the fixture plate for contacting the workpiece. In another instance, a fixture vise is used in which first, second, third and fourth locators are used and first and second fixture jaws are tightened to secure the workpiece. The fixture process also ranks the set of admissible fixture designs according to a predetermined quality metric so that the optimal fixture design for the desired purpose may be identified from the set of all admissible fixture designs. 44 figs.

An improved method for testing tension properties of fiber-reinforced polymer rebar

NASA Astrophysics Data System (ADS)

Yuan, Guoqing; Ma, Jian; Dong, Guohua

2010-03-01

We have conducted a series of tests to measure tensile strength and modulus of elasticity of fiber reinforced polymer (FRP) rebar. In these tests, the ends of each rebar specimen were embedded in steel tube filled with expansive cement, and the rebar was loaded by gripping the tubes with the conventional fixture during the tensile tests. However, most of specimens were failed at the ends where the section changed abruptly. Numerical simulations of the stress field at bar ends in such tests by ANSYS revealed that such unexpected failure modes were caused by the test setup. The changing abruptly of the section induced stress concentration. So the test results would be regarded as invalid. An improved testing method is developed in this paper to avoid this issue. A transition part was added between the free segment of the rebar and the tube, which could eliminate the stress concentration effectively and thus yield more accurate values for the properties of FRP rebar. The validity of the proposed method was demonstrated by both experimental tests and numerical analysis.

An improved method for testing tension properties of fiber-reinforced polymer rebar

NASA Astrophysics Data System (ADS)

Yuan, Guoqing; Ma, Jian; Dong, Guohua

2009-12-01

We have conducted a series of tests to measure tensile strength and modulus of elasticity of fiber reinforced polymer (FRP) rebar. In these tests, the ends of each rebar specimen were embedded in steel tube filled with expansive cement, and the rebar was loaded by gripping the tubes with the conventional fixture during the tensile tests. However, most of specimens were failed at the ends where the section changed abruptly. Numerical simulations of the stress field at bar ends in such tests by ANSYS revealed that such unexpected failure modes were caused by the test setup. The changing abruptly of the section induced stress concentration. So the test results would be regarded as invalid. An improved testing method is developed in this paper to avoid this issue. A transition part was added between the free segment of the rebar and the tube, which could eliminate the stress concentration effectively and thus yield more accurate values for the properties of FRP rebar. The validity of the proposed method was demonstrated by both experimental tests and numerical analysis.

KSC-2012-6433

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6444

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6434

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6442

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6441

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6440

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6432

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6443

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6431

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6437

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6435

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6436

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6448

NASA Image and Video Library

2012-12-06

CAPE CANAVERAL, Fla. – Technicians lower a special fixture around an Orion spacecraft inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6449

NASA Image and Video Library

2012-12-06

CAPE CANAVERAL, Fla. – Technicians lower a special fixture around an Orion spacecraft inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6450

NASA Image and Video Library

2012-12-06

CAPE CANAVERAL, Fla. – A special fixture stands in place around an Orion spacecraft inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6439

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

KSC-2012-6438

NASA Image and Video Library

2012-12-05

CAPE CANAVERAL, Fla. – Technicians prepare to fit a special fixture around an Orion capsule inside the high bay of the Operations & Checkout Building at NASA's Kennedy Space Center in Florida. The fixture is designed to enable precise pre-launch processing of the Orion spacecraft. An Orion capsule is being prepared to make a flight test in 2014 on a mission that will not carry any astronauts. Photo by Tim Jacobs

NASA's F-15B conducts a local Mach investigation flight over California's Mojave Desert.

NASA Image and Video Library

2004-06-01

NASA's F-15B Research Testbed aircraft flew instrumentation in June 2004 called the Local Mach Investigation (LMI), designed to gather local airflow data for future research projects using the aircraft's Propulsion Flight Test Fixture (PFTF). The PFTF is the black rectangular fixture attached to the aircraft's belly. The LMI package was located in the orange device attached to the PFTF.

NASA's F-15B conducts a local Mach investigation flight over California's Mojave Desert.

NASA Image and Video Library

2004-06-04

NASA's F-15B Research Testbed aircraft flew instrumentation in June 2004 called the Local Mach Investigation (LMI), designed to gather local airflow data for future research projects using the aircraft's Propulsion Flight Test Fixture (PFTF). The PFTF is the black rectangular fixture attached to the aircraft's belly. The LMI package was located in the orange device attached to the PFTF.

Transducer-Mounting Fixture

NASA Technical Reports Server (NTRS)

Spiegel, Kirk W.

1990-01-01

Transducer-mounting fixture holds transducer securely against stud. Projects only slightly beyond stud after installation. Flanged transducer fits into fixture when hinged halves open. When halves reclosed, fixture tightened onto threaded stud until stud makes contact with transducer. Knurled area on fixture aids in tightening fixture on stud.

In-Flight Vibration Environment of the NASA F-15B Flight Test Fixture

NASA Technical Reports Server (NTRS)

Corda, Stephen; Franz, Russell J.; Blanton, James N.; Vachon, M. Jake; DeBoer, James B.

2002-01-01

Flight vibration data are analyzed for the NASA F-15B/Flight Test Fixture II test bed. Understanding the in-flight vibration environment benefits design and integration of experiments on the test bed. The power spectral density (PSD) of accelerometer flight data is analyzed to quantify the in-flight vibration environment from a frequency of 15 Hz to 1325 Hz. These accelerometer data are analyzed for typical flight conditions and maneuvers. The vibration data are compared to flight-qualification random vibration test standards. The PSD levels in the lateral axis generally are greater than in the longitudinal and vertical axes and decrease with increasing frequency. At frequencies less than approximately 40 Hz, the highest PSD levels occur during takeoff and landing. Peaks in the PSD data for the test fixture occur at approximately 65, 85, 105-110, 200, 500, and 1000 Hz. The pitch-pulse and 2-g turn maneuvers produce PSD peaks at 115 Hz. For cruise conditions, the PSD level of the 85-Hz peak is greatest for transonic flight at Mach 0.9. From 400 Hz to 1325 Hz, the takeoff phase has the highest random vibration levels. The flight-measured vibration levels generally are substantially lower than the random vibration test curve.

Economic analysis of greenhouse lighting: light emitting diodes vs. high intensity discharge fixtures.

PubMed

Nelson, Jacob A; Bugbee, Bruce

2014-01-01

Lighting technologies for plant growth are improving rapidly, providing numerous options for supplemental lighting in greenhouses. Here we report the photosynthetic (400-700 nm) photon efficiency and photon distribution pattern of two double-ended HPS fixtures, five mogul-base HPS fixtures, ten LED fixtures, three ceramic metal halide fixtures, and two fluorescent fixtures. The two most efficient LED and the two most efficient double-ended HPS fixtures had nearly identical efficiencies at 1.66 to 1.70 micromoles per joule. These four fixtures represent a dramatic improvement over the 1.02 micromoles per joule efficiency of the mogul-base HPS fixtures that are in common use. The best ceramic metal halide and fluorescent fixtures had efficiencies of 1.46 and 0.95 micromoles per joule, respectively. We also calculated the initial capital cost of fixtures per photon delivered and determined that LED fixtures cost five to ten times more than HPS fixtures. The five-year electric plus fixture cost per mole of photons is thus 2.3 times higher for LED fixtures, due to high capital costs. Compared to electric costs, our analysis indicates that the long-term maintenance costs are small for both technologies. If widely spaced benches are a necessary part of a production system, the unique ability of LED fixtures to efficiently focus photons on specific areas can be used to improve the photon capture by plant canopies. Our analysis demonstrates, however, that the cost per photon delivered is higher in these systems, regardless of fixture category. The lowest lighting system costs are realized when an efficient fixture is coupled with effective canopy photon capture.

Orion Pad Abort 1 Crew Module Inertia Test Approach and Results

NASA Technical Reports Server (NTRS)

Herrera, Claudia; Harding, Adam

2010-01-01

The Flight Loads Laboratory at the Dryden Flight Research Center conducted tests to measure the inertia properties of the Orion Pad Abort 1 (PA-1) Crew Module. These measurements were taken to validate analytical predictions of the inertia properties of the vehicle and assist in reducing uncertainty for derived aero performance results calculated post launch. The first test conducted was to determine the Ixx of the Crew Module. This test approach used a modified torsion pendulum test step up that allowed the suspended Crew Module to rotate about the x axis. The second test used a different approach to measure both the Iyy and Izz properties. This test used a Knife Edge fixture that allowed small rotation of the Crew Module about the y and z axes. Discussions of the techniques and equations used to accomplish each test are presented. Comparisons with the predicted values used for the final flight calculations are made. Problem areas, with explanations and recommendations where available, are addressed. Finally, an evaluation of the value and success of these techniques to measure the moments of inertia of the Crew Module is provided.

Propulsion Flight-Test Fixture

NASA Technical Reports Server (NTRS)

Palumbo, Nate; Vachon, M. Jake; Richwine, Dave; Moes, Tim; Creech, Gray

2003-01-01

NASA Dryden Flight Research Center s new Propulsion Flight Test Fixture (PFTF), designed in house, is an airborne engine-testing facility that enables engineers to gather flight data on small experimental engines. Without the PFTF, it would be necessary to obtain such data from traditional wind tunnels, ground test stands, or laboratory test rigs. Traditionally, flight testing is reserved for the last phase of engine development. Generally, engines that embody new propulsion concepts are not put into flight environments until their designs are mature: in such cases, either vehicles are designed around the engines or else the engines are mounted in or on missiles. However, a captive carry capability of the PFTF makes it possible to test engines that feature air-breathing designs (for example, designs based on the rocket-based combined cycle) economically in subscale experiments. The discovery of unknowns made evident through flight tests provides valuable information to engine designers early in development, before key design decisions are made, thereby potentially affording large benefits in the long term. This is especially true in the transonic region of flight (from mach 0.9 to around 1.2), where it can be difficult to obtain data from wind tunnels and computational fluid dynamics. In January 2002, flight-envelope expansion to verify the design and capabilities of the PFTF was completed. The PFTF was flown on a specially equipped supersonic F-15B research testbed airplane, mounted on the airplane at a center-line attachment fixture, as shown in Figure 1. NASA s F-15B testbed has been used for several years as a flight-research platform. Equipped with extensive research air-data, video, and other instrumentation systems, the airplane carries externally mounted test articles. Traditionally, the majority of test articles flown have been mounted at the centerline tank-attachment fixture, which is a hard-point (essentially, a standardized weapon-mounting fixture). This hard-point has large weight margins, and, because it is located near the center of gravity of the airplane, the weight of equipment mounted there exerts a minimal effect on the stability and controllability of the airplane. The PFTF (see Figure 2) includes a one-piece aluminum structure that contains space for instrumentation, propellant tanks, and feed-system components. The PFTF also houses a force balance, on which is mounted the subscale engine or other experimental apparatus that is to be the subject of a flight test. The force balance measures a combination of inertial and aerodynamic forces and moments acting on the experimental apparatus.

Effect of target-fixture geometry on shock-wave compacted copper powders

NASA Astrophysics Data System (ADS)

Kim, Wooyeol; Ahn, Dong-Hyun; Yoon, Jae Ik; Park, Lee Ju; Kim, Hyoung Seop

2018-01-01

In shock compaction with a single gas gun system, a target fixture is used to safely recover a powder compact processed by shock-wave dynamic impact. However, no standard fixture geometry exists, and its effect on the processed compact is not well studied. In this study, two types of fixture are used for the dynamic compaction of hydrogen-reduced copper powders, and the mechanical properties and microstructures are investigated using the Vickers microhardness test and electron backscatter diffraction, respectively. With the assistance of finite element method simulations, we analyze several shock parameters that are experimentally hard to control. The results of the simulations indicate that the target geometry clearly affects the characteristics of incident and reflected shock waves. The hardness distribution and the microstructure of the compacts also show their dependence on the geometry. With the results of the simulations and the experiment, it is concluded that the target geometry affects the shock wave propagation and wave interaction in the specimen.

Using the tritium plasma experiment to evaluate ITER PFC safety

NASA Astrophysics Data System (ADS)

Longhurst, Glen R.; Anderl, Robert A.; Bartlit, John R.; Causey, Rion A.; Haines, John R.

1993-06-01

The Tritium Plasma Experiment was assembled at Sandia National Laboratories, Livermore and is being moved to the Tritium Systems Test Assembly facility at Los Alamos National Laboratory to investigate interactions between dense plasmas at low energies and plasma-facing component materials. This apparatus has the unique capabilty of replicating plasma conditions in a tokamak divertor with particle flux densities of 2 × 1023 ions/m2.s and a plasma temperature of about 15 eV using a plasma that includes tritium. An experimental program has been initiated using the Tritium Plasma Experiment to examine safety issues related to tritium in plasma-facing components, particularly the ITER divertor. Those issues include tritium retention and release characteristics, tritium permeation rates and transient times to coolant streams, surface modification and erosion by the plasma, the effects of thermal loads and cycling, and particulate production. An industrial consortium led by McDonnell Douglas will design and fabricate the test fixtures.

Evaluation of the Edge Crack Torsion (ECT) Test for Mode 3 Interlaminar Fracture Toughness of Laminated Composites

NASA Technical Reports Server (NTRS)

Li, Jian; Lee, Edward W.; OBrien, T. Kevin; Lee, Shaw Ming

1996-01-01

An analytical and experimental investigation was carried out on G40-800/R6376 graphite epoxy laminates to evaluate the Edge Crack Torsion (ECT) test as a candidate for a standard Mode 3 interlaminar fracture toughness test for laminated composites. The ECT test consists of a (90/(+/- 45)(sub 3)/(+/- 45)(sub 3)/90))(sub s) laminate with a delamination introduced by a non-adhesive film at the mid-plane along one edge and loaded in a special fixture to create torsion along the length of the laminate. Dye penetrate enhanced X-radiograph of failed specimens revealed that the delamination initiated at the middle of the specimen length and propagated in a self similar manner along the laminate mid-plane. A three-dimensional finite element analysis was performed that indicated that a pure Mode 3 delamination exists at the middle of specimen length away from both ends. At the ends near the loading point a small Mode 2 component exists. However, the magnitude of this Mode 2 strain energy release rate at the loading point is small compared to the magnitude of Mode 3 component in the mid-section of the specimen. Hence, the ECT test yielded the desired Mode 3 delamination. The Mode 3 fracture toughness was obtained from a compliance calibration method and was in good agreement with the finite element results. Mode 2 End-Notched Flexure (ENF) tests and Mode 1 Double Cantilever Beam (DCB) tests were also performed for the same composite material. The Mode 1 fracture toughness was much smaller than both the Mode 2 and Mode 3 fracture toughness. The Mode 2 fracture toughness was found to be 75% of the Mode 3 fracture toughness.

Immediate loading of titanium hexed screw-type implants in the edentulous patient: case report.

PubMed

Calvo, M P; Muller, E; Garg, A K

2000-01-01

Histologic and histomorphometric studies in both animals and humans have shown that more rapid and greater bone-to-implant contact can be achieved with implants that incorporate certain surface characteristics compared with the original machined-surface implants. Such findings are significant because various implant designs may allow the fixtures to sufficiently resist functional loading sooner than originally thought. The case report presented here indicates that immediate loading of hexed titanium screw-type implants in the anterior mandible can lead to successful osseointegration and clinical outcome. The number of implants placed, their distribution, and the type of rigid connection are critical considerations for immediate loading. A bone height that can accommodate dental implants > or = 10 mm long is recommended. Biomechanically, the implants to be immediately loaded must be stable and resistant to macromovement to ensure good osseointegration.

An Overview of Advanced Elastomeric Seal Development and Testing Capabilities at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.

2014-01-01

NASA is developing advanced space-rated elastomeric seals to support future space exploration missions to low Earth orbit, the Moon, near Earth asteroids, and other destinations. This includes seals for a new docking system and vehicle hatches. These seals must exhibit extremely low leak rates to ensure that astronauts have sufficient breathable air for extended missions. Seal compression loads must be below prescribed limits so as not to overload the mechanisms that compress them, and seal adhesion forces must be low to allow the sealed interface to be separated when required (e.g., during undocking or hatch opening). NASA Glenn Research Center has developed a number of unique test fixtures to measure the leak rates and compression and adhesion loads of candidate seal designs under simulated thermal, vacuum, and engagement conditions. Tests can be performed on fullscale seals with diameters on the order of 50 in., subscale seals that are about 12 in. in diameter, and smaller specimens such as O-rings. Test conditions include temperatures ranging from -238 to 662degF (-150 to 350degC), operational pressure gradients, and seal-on-seal or seal-on-flange mating configurations. Nominal and off-nominal conditions (e.g., incomplete seal compression) can also be simulated. This paper describes the main design features and capabilities of each type of test apparatus and provides an overview of advanced seal development activities at NASA Glenn.

An Overview of Advanced Elastomeric Seal Development and Testing Capabilities at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H.

2014-01-01

NASA is developing advanced space-rated elastomeric seals to support future space exploration missions to low Earth orbit, the Moon, near Earth asteroids, and other destinations. This includes seals for a new docking system and vehicle hatches. These seals must exhibit extremely low leak rates to ensure that astronauts have sufficient breathable air for extended missions. Seal compression loads must be below prescribed limits so as not to overload the mechanisms that compress them, and seal adhesion forces must be low to allow the sealed interface to be separated when required (e.g., during undocking or hatch opening). NASA Glenn Research Center has developed a number of unique test fixtures to measure the leak rates and compression and adhesion loads of candidate seal designs under simulated thermal, vacuum, and engagement conditions. Tests can be performed on full-scale seals with diameters on the order of 50 in., subscale seals that are about 12 in. in diameter, and smaller specimens such as O-rings. Test conditions include temperatures ranging from -238 to 662 F (-150 to 350 C), operational pressure gradients, and seal-on-seal or seal-on-flange mating configurations. Nominal and off-nominal conditions (e.g., incomplete seal compression) can also be simulated. This paper describes the main design features and capabilities of each type of test apparatus and provides an overview of advanced seal development activities at NASA Glenn.

Fixture for forming evaporative pattern (EPC) process patterns

DOEpatents

Turner, Paul C.; Jordan, Ronald R.; Hansen, Jeffrey S.

1993-01-01

A method of casting metal using evaporative pattern casting process patterns in combination with a fixture for creating and maintaining a desired configuration in flexible patterns. A pattern is constructed and gently bent to the curvature of a suitable fixture. String or thin wire, which burns off during casting, is used to tie the pattern to the fixture. The fixture with pattern is dipped in a commercially available refractory wash to prevent metal adherence and sticking to the fixture. When the refractory wash is dry, the fixture and pattern are placed in a flask, and sand is added and compacted by vibration. The pattern remains in position, restrained by the fixture. Metal that is poured directly into the pattern replaces the pattern exactly but does not contact or weld to the fixture due to the protective refractory layer. When solid, the casting is easily separated from the fixture. The fixture can be cleaned for reuse in conventional casting cleaning equipment.

Test Methodology Development for Experimental Structural Assessment of ASC Planar Spring Material for Long-Term Durability

NASA Technical Reports Server (NTRS)

Yun, Gunjin; Abdullah, A. B. M.; Binienda, Wieslaw; Krause, David L.; Kalluri, Sreeramesh

2014-01-01

A vibration-based testing methodology has been developed that will assess fatigue behavior of the metallic material of construction for the Advanced Stirling Convertor displacer (planar) spring component. To minimize the testing duration, the test setup is designed for base-excitation of a multiplespecimen arrangement, driven in a high-frequency resonant mode; this allows completion of fatigue testing in an accelerated period. A high performance electro-dynamic exciter (shaker) is used to generate harmonic oscillation of cantilever beam specimens, which are clasped on the shaker armature with specially-designed clamp fixtures. The shaker operates in closed-loop control with dynamic specimen response feedback provided by a scanning laser vibrometer. A test coordinator function synchronizes the shaker controller and the laser vibrometer to complete the closed-loop scheme. The test coordinator also monitors structural health of the test specimens throughout the test period, recognizing any change in specimen dynamic behavior. As this may be due to fatigue crack initiation, the test coordinator terminates test progression and then acquires test data in an orderly manner. Design of the specimen and fixture geometry was completed by finite element analysis such that peak stress does not occur at the clamping fixture attachment points. Experimental stress evaluation was conducted to verify the specimen stress predictions. A successful application of the experimental methodology was demonstrated by validation tests with carbon steel specimens subjected to fully-reversed bending stress; high-cycle fatigue failures were induced in such specimens using higher-than-prototypical stresses

Counterrotating-Shoulder Mechanism for Friction Stir Welding

NASA Technical Reports Server (NTRS)

Nunes, Arthur C., Jr.

2007-01-01

A counterrotating-shoulder mechanism has been proposed as an alternative to the mechanism and fixtures used in conventional friction stir welding. The mechanism would internally react most or all of the forces and torques exerted on the workpiece, making it unnecessary to react the forces and torques through massive external fixtures. In conventional friction stir welding, a rotating pin tool is inserted into, and moved along, a weld seam. As the pin tool moves, it stirs together material from the opposite sides of the seam to form the weld. A large axial plunge force must be exerted upon the workpiece through and by the pin tool and a shoulder attached above the pin tool in order to maintain the pressure necessary for the process. The workpiece is secured on top of an anvil, which supports the workpiece against the axial plunge force and against the torque exerted by the pin tool and shoulder. The anvil and associated fixtures must be made heavy (and, therefore, are expensive) to keep the workpiece stationary. In addition, workpiece geometries must be limited to those that can be accommodated by the fixtures. The predecessor of the proposed counterrotating-shoulder mechanism is a second-generation, self-reacting tool, resembling a bobbin, that makes it possible to dispense with the heavy anvil. This tool consists essentially of a rotating pin tool with opposing shoulders. Although the opposing shoulders maintain the necessary pressure without need to externally apply or react a large plunge force, the torque exerted on the workpiece remains unreacted in the absence of a substantial external fixture. Depending on the RPM and the thickness of the workpiece, the torque can be large. The proposed mechanism (see figure) would include a spindle attached to a pin tool with a lower shoulder. The spindle would be coupled via splines to the upper one of three bevel gears in a differential drive. The middle bevel gear would be the power-input gear and would be coupled to the upper and lower bevel gears. The lower bevel gear would be attached to the upper shoulder and would slide and rotate freely over the spindle. The spindle would be fastened by its threaded upper end to an external submechanism that would exert axial tension on the spindle to load the workpiece in compression between the shoulders. By reducing or eliminating (relative to the use of a self reacting tool) the torque that must be reacted externally, the use of the proposed tool would reduce the tendency toward distortion or slippage of the workpiece. To begin a weld, the spindle would be inserted through a hole in the workpiece or run-on tab at the beginning of the seam and fastened to the loading submechanism. Rotation and axial loading would be increased gradually from zero and, after a time to be determined by trial and error, translation along the weld seam would be increased gradually from zero to a steady weld speed. The weld would be ended by running the mechanism off the workpiece or, if the lower shoulder were detachable, by detaching the lower shoulder from the spindle and pulling the pin tool out.

Hollow Abutment Screw Design for Easy Retrieval in Case of Screw Fracture in Dental Implant System

PubMed Central

Kim, Bongju; Shin, Yoo Jin

2017-01-01

The prosthetic component of dental implant is attached on the abutment which is connected to the fixture with an abutment screw. The abutment screw fracture is not frequent; however, the retrieval of the fractured screw is not easy, and it poses complications. A retrieval kit was developed which utilizes screw removal drills to make a hole on the fractured screw that provides an engaging drill to unscrew it. To minimize this process, the abutment screw is modified with a prefabricated access hole for easy retrieval. This study aimed to introduce this modified design of the abutment screw, the concept of easy retrieval, and to compare the mechanical strengths of the conventional and hollow abutment screws by finite element analysis (FEA) and mechanical test. In the FEA results, both types of abutment screws showed similar stress distribution in the single artificial tooth system. A maximum load difference of about 2% occurred in the vertical load by a mechanical test. This study showed that the hollow abutment screw may be an alternative to the conventional abutment screws because this is designed for easy retrieval and that both abutment screws showed no significant difference in the mechanical tests and in the FEA. PMID:29065610

Transfer orbit stage mechanisms thermal vacuum test

NASA Technical Reports Server (NTRS)

Oleary, Scott T.

1990-01-01

A systems level mechanisms test was conducted on the Orbital Sciences Corp.'s Transfer Orbit Stage (TOS). The TOS is a unique partially reusable transfer vehicle which will boost a satellite into its operational orbit from the Space Shuttle's cargo bay. The mechanical cradle and tilt assemblies will return to earth with the Space Shuttle while the Solid Rocket Motor (SRM) and avionics package are expended. A mechanisms test was performed on the forward cradle and aft tilting assemblies of the TOS under thermal vacuum conditions. Actuating these assemblies under a 1 g environment and thermal vacuum conditions proved to be a complex task. Pneumatic test fixturing was used to lift the forward cradle, and tilt the SRM, and avionics package. Clinometers, linear voltage displacement transducers, and load cells were used in the thermal vacuum chamber to measure the performance and characteristics of the TOS mechanism assembly. Incorporation of the instrumentation and pneumatic system into the test setup was not routine since pneumatic actuation of flight hardware had not been previously performed in the facility. The methods used are presented along with the problems experienced during the design, setup and test phases.

Passive Magnetic Bearing With Ferrofluid Stabilization

NASA Technical Reports Server (NTRS)

Jansen, Ralph; DiRusso, Eliseo

1996-01-01

A new class of magnetic bearings is shown to exist analytically and is demonstrated experimentally. The class of magnetic bearings utilize a ferrofluid/solid magnet interaction to stabilize the axial degree of freedom of a permanent magnet radial bearing. Twenty six permanent magnet bearing designs and twenty two ferrofluid stabilizer designs are evaluated. Two types of radial bearing designs are tested to determine their force and stiffness utilizing two methods. The first method is based on the use of frequency measurements to determine stiffness by utilizing an analytical model. The second method consisted of loading the system and measuring displacement in order to measure stiffness. Two ferrofluid stabilizers are tested and force displacement curves are measured. Two experimental test fixtures are designed and constructed in order to conduct the stiffness testing. Polynomial models of the data are generated and used to design the bearing prototype. The prototype was constructed and tested and shown to be stable. Further testing shows the possibility of using this technology for vibration isolation. The project successfully demonstrated the viability of the passive magnetic bearing with ferrofluid stabilization both experimentally and analytically.

Computational Simulations and the Scientific Method

NASA Technical Reports Server (NTRS)

Kleb, Bil; Wood, Bill

2005-01-01

As scientific simulation software becomes more complicated, the scientific-software implementor's need for component tests from new model developers becomes more crucial. The community's ability to follow the basic premise of the Scientific Method requires independently repeatable experiments, and model innovators are in the best position to create these test fixtures. Scientific software developers also need to quickly judge the value of the new model, i.e., its cost-to-benefit ratio in terms of gains provided by the new model and implementation risks such as cost, time, and quality. This paper asks two questions. The first is whether other scientific software developers would find published component tests useful, and the second is whether model innovators think publishing test fixtures is a feasible approach.

In-line thermoelectric module

DOEpatents

Pento, Robert; Marks, James E.; Staffanson, Clifford D.

2000-01-01

A thermoelectric module with a plurality of electricity generating units each having a first end and a second end, the units being arranged first end to second end along an in-line axis. Each unit includes first and second elements each made of a thermoelectric material, an electrically conductive hot member arranged to heat one side of the first element, and an electrically conductive cold member arranged to cool another side of the first element and to cool one side of the second element. The hot member, the first element, the cold member and the second element are supported in a fixture, are electrically connected respectively to provide an electricity generating unit, and are arranged respectively in positions along the in-line axis. The individual components of each generating unit and the respective generating units are clamped in their in-line positions by a loading bolt at one end of the fixture and a stop wall at the other end of the fixture. The hot members may have a T-shape and the cold members an hourglass shape to facilitate heat transfer. The direction of heat transfer through the hot members may be perpendicular to the direction of heat transfer through the cold members, and both of these heat transfer directions may be perpendicular to the direction of current flow through the module.

Umbilical Stiffness Matrix Characterization and Testing for Microgravity Science Payloads

NASA Technical Reports Server (NTRS)

Engberg, Robert C.

2003-01-01

This paper describes efforts of testing and analysis of various candidate cables and umbilicals for International Space Station microgravity science payloads. The effects of looping, large vs. small displacements, and umbilical mounting configurations were assessed. A 3-DOF stepper motor driven fixture was used to excite the umbilicals. Forces and moments were directly measured in all three axes with a 6-DOF load cell in order to derive suitable stiffness matrices for design and analysis of vibration isolation controllers. Data obtained from these tests were used to help determine the optimum type and configuration of umbilical cables for the International Space Station microgravity science glovebox (MSG) vibration isolation platform. The data and procedures can also be implemented into control algorithm simulations to assist in validation of actively controlled vibration isolation systems. The experimental results of this work are specific in support of the Glovebox Integrated Microgravity Isolation Technology (g-LIMIT) isolation platform, to be located in the microgravity science glovebox aboard the U.S. Destiny Laboratory Module.

Support apparatus for semiconductor wafer processing

DOEpatents

Griffiths, Stewart K.; Nilson, Robert H.; Torres, Kenneth J.

2003-06-10

A support apparatus for minimizing gravitational stress in semiconductor wafers, and particularly silicon wafers, during thermal processing. The support apparatus comprises two concentric circular support structures disposed on a common support fixture. The two concentric circular support structures, located generally at between 10 and 70% and 70 and 100% and preferably at 35 and 82.3% of the semiconductor wafer radius, can be either solid rings or a plurality of spaced support points spaced apart from each other in a substantially uniform manner. Further, the support structures can have segments removed to facilitate wafer loading and unloading. In order to withstand the elevated temperatures encountered during semiconductor wafer processing, the support apparatus, including the concentric circular support structures and support fixture can be fabricated from refractory materials, such as silicon carbide, quartz and graphite. The claimed wafer support apparatus can be readily adapted for use in either batch or single-wafer processors.

Optimization of test parameters for quantitative stress measurements using the miniaturized disk-bend test

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

Meyers, D.E.; Chen, F.C.; Zhang, J.

A recently-developed miniaturized disk-bend test (MDBT) has been successfully used to evaluate the mechanical properties of a variety of materials, using specimens 3 mm in diameter. The load is applied either by a solid ball (the ball-on ring (BOR) mode), or by a hollow cylinder (the ring-on-ring (ROR) mode). They authors have reproduced the yield stresses of ordered intermetallic compounds and the fracture toughness of several ceramics using analytical solutions to the equations of elasticity theory. Despite this success there are several curious features involved in the analysis of data; for example, in previous tests conducted in the BOR modemore » correct values of the yield stress were obtained using the equations appropriate to clamped specimens, whether or not hey were actually clamped in the test fixture. They show that this is ubiquitous to tests in the BOR mode, and does not arise because of frictional constraints at the supporting ring. They have also completed a thorough evaluation of testing in the ROR mode, in which the yield stresses of cold-rolled or annealed AISI type 302 stainless steel were measured using various combinations of specimen thickness and radii of the loading and supporting rings, and compared to those of tensile specimens machined from the same material. The most accurate and reproducible measurements of the yield strength were obtained for specific combinations of specimen thickness and geometry of the apparatus.« less

Sinus Floor Elevation with Modified Crestal Approach and Single Loaded Short Implants: A Case Report with 4 Years of Follow-Up

PubMed Central

Perelli, Michele; Abundo, Roberto; Corrente, Giuseppe; Saccone, Carlo

2017-01-01

Tooth extraction is usually followed by bone reduction. In the maxillary posterior region, this remodelling combined with sinus pneumatisation and periodontal defects may lead to a reduced basal bone height available for implant placement. Sinus floor elevation can be performed with different surgical techniques. Crestal approach has demonstrated to be effective, less invasive, and associated with a reduced morbidity. This article reports a modified sinus floor elevation by means of rotary, noncutting instruments, addition of xenograft, and 2 short-threaded implant placements. The aim of the study was to evaluate the implant's success and intrasinus radiographical bone gain after 4 years of functional loading. The premolar implant site presented a starting basal bone height of 6 mm, while the molar site was of 2 mm. In the first surgical step, sinus floor elevation was performed mesially and the implant was inserted, and distally only sinus floor elevation was performed. After 6 months, the mesial implant was uncovered and the second implant was inserted; 4 months later, the second fixture was uncovered, and both fixtures were loaded with single provisional screw-retained crowns and later with single screw-retained porcelain fused to metal crowns. Implants integrated successfully, and crestal bone remodelling did not exceed the smooth collar. Bone gain was 3 mm for the mesial implant and more than 5 mm for the distal one. PMID:29403665

Sinus Floor Elevation with Modified Crestal Approach and Single Loaded Short Implants: A Case Report with 4 Years of Follow-Up.

PubMed

Perelli, Michele; Abundo, Roberto; Corrente, Giuseppe; Saccone, Carlo; Arduino, Paolo G

2017-01-01

Tooth extraction is usually followed by bone reduction. In the maxillary posterior region, this remodelling combined with sinus pneumatisation and periodontal defects may lead to a reduced basal bone height available for implant placement. Sinus floor elevation can be performed with different surgical techniques. Crestal approach has demonstrated to be effective, less invasive, and associated with a reduced morbidity. This article reports a modified sinus floor elevation by means of rotary, noncutting instruments, addition of xenograft, and 2 short-threaded implant placements. The aim of the study was to evaluate the implant's success and intrasinus radiographical bone gain after 4 years of functional loading. The premolar implant site presented a starting basal bone height of 6 mm, while the molar site was of 2 mm. In the first surgical step, sinus floor elevation was performed mesially and the implant was inserted, and distally only sinus floor elevation was performed. After 6 months, the mesial implant was uncovered and the second implant was inserted; 4 months later, the second fixture was uncovered, and both fixtures were loaded with single provisional screw-retained crowns and later with single screw-retained porcelain fused to metal crowns. Implants integrated successfully, and crestal bone remodelling did not exceed the smooth collar. Bone gain was 3 mm for the mesial implant and more than 5 mm for the distal one.

Vibration and Acoustic Testing for Mars Micromission Spacecraft

NASA Technical Reports Server (NTRS)

Kern, Dennis L.; Scharton, Terry D.

1999-01-01

The objective of the Mars Micromission program being managed by the Jet Propulsion Laboratory (JPL) for NASA is to develop a common spacecraft that can carry telecommunications equipment and a variety of science payloads for exploration of Mars. The spacecraft will be capable of carrying robot landers and rovers, cameras, probes, balloons, gliders or aircraft, and telecommunications equipment to Mars at much lower cost than recent NASA Mars missions. The lightweight spacecraft (about 220 Kg mass) will be launched in a cooperative venture with CNES as a TWIN auxiliary payload on the Ariane 5 launch vehicle. Two or more Mars Micromission launches are planned for each Mars launch opportunity, which occur every 26 months. The Mars launch window for the first mission is November 1, 2002 through April 2003, which is planned to be a Mars airplane technology demonstration mission to coincide with the 100 year anniversary of the Kittyhawk flight. Several subsequent launches will create a telecommunications network orbiting Mars, which will provide for continuous communication with lenders and rovers on the Martian surface. Dedicated science payload flights to Mars are slated to start in 2005. This new cheaper and faster approach to Mars exploration calls for innovative approaches to the qualification of the Mars Micromission spacecraft for the Ariane 5 launch vibration and acoustic environments. JPL has in recent years implemented new approaches to spacecraft testing that may be effectively applied to the Mars Micromission. These include 1) force limited vibration testing, 2) combined loads, vibration and modal testing, and 3) direct acoustic testing. JPL has performed nearly 200 force limited vibration tests in the past 9 years; several of the tests were on spacecraft and large instruments, including the Cassini and Deep Space One spacecraft. Force limiting, which measures and limits the spacecraft base reaction force using triaxial force gages sandwiched between the spacecraft and the test fixture, alleviates the severe overtest at spacecraft resonances inherent in rigid fixture vibration tests. It has the distinct advantage over response limiting that the method is not dependent on the accuracy of a detailed dynamic model of the spacecraft. Combined loads, vibration, and modal testing were recently performed on the QuikSCAT spacecraft. The combined tests were performed in a single test setup per axis on a vibration shaker, reducing test time by a factor of two or three. Force gages were employed to measure the true c.g. acceleration of the spacecraft for structural loads verification using a sine burst test, to automatically notch random vibration test input accelerations at spacecraft resonances based on predetermined force limits, and to directly measure modal masses in a base drive modal test. In addition to these combined tests on the shaker, the QuikSCAT spacecraft was subjected to a direct field acoustic test by surrounding the spacecraft, still on the vibration shaker, with rock concert type acoustic speakers. Since the spacecraft contractor does not have a reverberant field acoustic test facility, performing a direct field acoustic test -saved the program nearly two weeks schedule time that would have been required for packing / unpacking and shipping of the spacecraft. This paper discusses the rationale behind and advantages of the above test approaches and provides examples of their actual implementation and comparisons to flight data. The applicability of the test approaches to Mars Micromission spacecraft qualification is discussed.

Testing filamentary composites

NASA Technical Reports Server (NTRS)

Dow, N. F.; Rosen, B. W.

1970-01-01

NOL ring split-dee tensile test has the advantages that the specimen is readily fabricated by winding and the test is performed in a conventional testing machine without special fixtures. Strain gages cannot be mounted, however, and substantial bending moments are introduced.

Noise and cardiovascular effects in workers of the sanitary fixtures industry.

PubMed

Assunta, Capozzella; Ilaria, Samperi; Simone, De Sio; Gianfranco, Tomei; Teodorico, Casale; Carmina, Sacco; Anastasia, Suppi; Roberto, Giubilati; Francesco, Tomei; Valeria, Rosati Maria

2015-01-01

The aim of the present study is to evaluate whether workers in the sanitary fixtures industry are a category at risk of developing cardiovascular diseases, and in particular, whether chronic noise exposure may play a role in cardiovascular effects in exposed workers. Seventy-five employees engaged in sanitation fixtures production and a control group of sixty-four office workers, who were not exposed to agents that could damage the cardiovascular system, participated in our study. The selected workers completed a clinical-anamnestic questionnaire, and underwent a medical examination, blood pressure test, electrocardiogram (ECG), blood tests, and audiometry. Measurements of environmental noise, dust, and lead were also carried out. The exposed workers, in comparison to the control group, showed a higher frequency of hypertension, systolic and diastolic blood pressure (p<0.05, p<0.05), as well as electrocardiographic abnormalities (p<0.05). There was also a higher frequency of hypertension and electrocardiographic abnormalities among subjects with audiometric deficit compared to normoacoustic subjects (p<0.05 and p<0.05). from our study suggest that work activity in the sanitary fixtures industry can have an influence on the cardiovascular system, and noise can be the main cause of damage for the cardiovascular system in exposed workers, as cardiovascular damage seems to be linked to hearing loss. Copyright © 2014 Elsevier GmbH. All rights reserved.

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

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

Rabin, B. H.; Lloyd, W. R.; Schulthess, J. L.

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)more » 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/cm 3 to 6.0 x 1021 fissions/cm 3. 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.« less

Characterization and Comparison of Vibration Transfer Paths in a Helicopter Gearbox and a Fixture Mounted Gearbox

NASA Technical Reports Server (NTRS)

Islam, Akm Anwarul; Dempsey, Paula J.; Feldman, Jason; Larsen, Chris

2014-01-01

Health monitoring of rotorcraft components, currently being performed by Health and Usage Monitoring Systems through analyses of vibration signatures of dynamic mechanical components, is very important for their safe and economic operation. HUMS analyze vibration signatures associated with faults and quantify them as condition indicators to predict component behavior. Vibration transfer paths are characterized by frequency response functions derived from the input/output relationship between applied force and dynamic response through a structure as a function of frequency. With an objective to investigate the differences in transfer paths, transfer path measurements were recorded under similar conditions in the left and right nose gearboxes of an AH-64 helicopter and in an isolated left nose gearbox in a test fixture at NASA Glenn Research Center. The test fixture enabled the application of measured torques-common during an actual operation. An impact hammer as well as commercial and lab piezo shakers, were used in conjunction with two types of commercially available accelerometers to collect the vibration response under various test conditions. The frequency response functions measured under comparable conditions of both systems were found to be consistent. Measurements made on the fixture indicated certain real-world installation and maintenance issues, such as sensor alignments, accelerometer locations and installation torques, had minimal effect. However, gear vibration transfer path dynamics appeared to be somewhat dependent on the presence of oil, and the transfer path dynamics were notably different if the force input was on the internal ring gear rather than on the external gearbox case.

Method for Estimating Thread Strength Reduction of Damaged Parent Holes with Inserts

NASA Technical Reports Server (NTRS)

Johnson, David L.; Stratton, Troy C.

2005-01-01

During normal assembly and disassembly of bolted-joint components, thread damage and/or deformation may occur. If threads are overloaded, thread damage/deformation can also be anticipated. Typical inspection techniques (e.g. using GO-NO GO gages) may not provide adequate visibility of the extent of thread damage. More detailed inspection techniques have provided actual pitch-diameter profiles of damaged-hardware holes. A method to predict the reduction in thread shear-out capacity of damaged threaded holes has been developed. This method was based on testing and analytical modeling. Test samples were machined to simulate damaged holes in the hardware of interest. Test samples containing pristine parent-holes were also manufactured from the same bar-stock material to provide baseline results for comparison purposes. After the particular parent-hole thread profile was machined into each sample a helical insert was installed into the threaded hole. These samples were tested in a specially designed fixture to determine the maximum load required to shear out the parent threads. It was determined from the pristine-hole samples that, for the specific material tested, each individual thread could resist an average load of 3980 pounds. The shear-out loads of the holes having modified pitch diameters were compared to the ultimate loads of the specimens with pristine holes. An equivalent number of missing helical coil threads was then determined based on the ratio of shear-out loads for each thread configuration. These data were compared with the results from a finite element model (FEM). The model gave insights into the ability of the thread loads to redistribute for both pristine and simulated damage configurations. In this case, it was determined that the overall potential reduction in thread load-carrying capability in the hardware of interest was equal to having up to three fewer threads in the hole that bolt threads could engage. One- half of this potential reduction was due to local pitch-diameter variations and the other half was due to overall pitch-diameter enlargement beyond Class 2 fit. This result was important in that the thread shear capacity for this particular hardware design was the limiting structural capability. The details of the method development, including the supporting testing, data reduction and analytical model results comparison will be discussed hereafter.

Externally Pressurized Journal Gas Bearings

NASA Technical Reports Server (NTRS)

Laub, John H.

1959-01-01

Externally pressurized gas-lubricated bearings with multiple orifice feed are investigated. An analytical treatment is developed for a semi-cylindrical bearing with 9 orifices and for a cylindrical journal bearing with 192 radial and 24 axial orifices. Experiments are described on models of the two bearing configurations with specially designed fixtures which incorporate pneumatic loading and means for determining pressure profiles, gas flow and gap height. The correlation between theory and experiment is satisfactory.

Orion Pad Abort 1 Crew Module Mass Properties Test Approach and Results

NASA Technical Reports Server (NTRS)

Herrera, Claudia; Harding, Adam

2012-01-01

The Flight Loads Laboratory at the Dryden Flight Research Center conducted tests to measure the inertia properties of the Orion Pad Abort 1 (PA-1) Crew Module (CM). These measurements were taken to validate analytical predictions of the inertia properties of the vehicle and assist in reducing uncertainty for derived aero performance coefficients to be calculated post-launch. The first test conducted was to determine the Ixx of the Crew Module. This test approach used a modified torsion pendulum test setup that allowed the suspended Crew Module to rotate about the x axis. The second test used a different approach to measure both the Iyy and Izz properties. This test used a Knife Edge fixture that allowed small rotation of the Crew Module about the y and z axes. Discussions of the techniques and equations used to accomplish each test are presented. Comparisons with the predicted values used for the final flight calculations are made. Problem areas, with explanations and recommendations where available, are addressed. Finally, an evaluation of the value and success of these techniques to measure the moments of inertia of the Crew Module is provided.

Strength and Structure of Ga1-xInx as Alloys

DTIC Science & Technology

1986-04-01

fixtures were ordered and received. An existing furnace and retort will be used to surround the compression fixture. The sample will be positioned in a B203...oncerns the experimental measurement of the flow stress and hardness as a function of temperature and In content:. High mprare hardns testing is used ...approximately 1/3 of the hardness 4 value9 so the latter indicates expected trends for yield stress. flWI1AL WORK The hardess tester used in this study was

Loading Considerations for Implementing Friction STIR Welding for Large Diameter Tank Fabrication

NASA Technical Reports Server (NTRS)

Adams, Glynn

1998-01-01

The main objectives of the research presented here are to determine the reaction loads associated with friction stir welding (FSW) and to determine the suitability of an existing welding fixture for implementing this welding process in the fabrication of large diameter tanks. Friction stir welding is a relatively new process which is being investigated as a method for joining aluminum alloys. The aluminum-lithium alloy, Al-Li 2195, which is being used to fabricate the super-light-weight shuttle external tank has proven difficult to join using fusion techniques. Therefore, FSW and its potential applicability to joining Al-Li 2195 are of particular interest to NASA.

Evaluation of a single cell and candidate materials with high water content hydrogen in a generic solid oxide fuel cell stack test fixture, Part II: materials and interface characterization

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

Chou, Y. S.; Stevenson, Jeffry W.; Choi, Jung-Pyung

2013-01-01

A generic solid oxide fuel cell (SOFC) test fixture was developed to evaluate candidate materials under realistic conditions. A commerical 50 mm x 50 mm NiO-YSZ anode supported thin YSZ electrolyte cell with lanthanum strontium manganite (LSM) cathode was tested to evaluate the stability of candidate materials. The cell was tested in two stages at 800oC: stage I of low (~3% H2O) humidity and stage II of high (~30% H2O) humidity hydrogen fuel at constant voltage or constant current mode. Part I of the work was published earlier with information of the generic test fixture design, materials, cell performance, andmore » optical post-mortem analysis. In part II, detailed microstructure and interfacial characterizations are reported regarding the SOFC candidate materials: (Mn,Co)-spinel conductive coating, alumina coating for sealing area, ferritic stainless steel interconnect, refractory sealing glass, and their interactions with each other. Overall, the (Mn,Co)-spinel coating was very effective in minimizing Cr migration. No Cr was identified in the cathode after 1720h at 800oC. Aluminization of metallic interconnect also proved to be chemically compatible with alkaline-earth silicate sealing glass. The details of interfacial reaction and microstructure development are discussed.« less

46 CFR 120.410 - Lighting fixtures.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Each table lamp, desk lamp, floor lamp, or similar equipment must be secured in place so that it cannot... Fixtures,” UL 1571, “Incandescent Lighting Fixtures,” UL 1572, “High Intensity Discharge Lighting Fixtures...

Robust QCT/FEA Models of Proximal Femur Stiffness and Fracture Load During a Sideways Fall on the Hip

PubMed Central

Dragomir-Daescu, Dan; Buijs, Jorn Op Den; McEligot, Sean; Dai, Yifei; Entwistle, Rachel C.; Salas, Christina; Melton, L. Joseph; Bennet, Kevin E.; Khosla, Sundeep; Amin, Shreyasee

2013-01-01

Clinical implementation of quantitative computed tomography-based finite element analysis (QCT/FEA) of proximal femur stiffness and strength to assess the likelihood of proximal femur (hip) fractures requires a unified modeling procedure, consistency in predicting bone mechanical properties, and validation with realistic test data that represent typical hip fractures, specifically, a sideways fall on the hip. We, therefore, used two sets (n = 9, each) of cadaveric femora with bone densities varying from normal to osteoporotic to build, refine, and validate a new class of QCT/FEA models for hip fracture under loading conditions that simulate a sideways fall on the hip. Convergence requirements of finite element models of the first set of femora led to the creation of a new meshing strategy and a robust process to model proximal femur geometry and material properties from QCT images. We used a second set of femora to cross-validate the model parameters derived from the first set. Refined models were validated experimentally by fracturing femora using specially designed fixtures, load cells, and high speed video capture. CT image reconstructions of fractured femora were created to classify the fractures. The predicted stiffness (cross-validation R2 = 0.87), fracture load (cross-validation R2 = 0.85), and fracture patterns (83% agreement) correlated well with experimental data. PMID:21052839

Fixture congestion modulates post-match recovery kinetics in professional soccer players.

PubMed

Lundberg, Tommy R; Weckström, Kristoffer

2017-01-01

This study examined the influence of fixture congestion on physical performance and biochemical variables in professional male footballers. After 3 competitive matches within a week (3M cycle), 16 players underwent blood sampling and field testing 72 h after the last match. The same tests were performed after a regular 1 match-week cycle (1M cycle). The 1M vs. 3M change scores were compared between Congested (high match exposure) and non-selected Control players. The change score in muscle soreness was greater (effect size 1.0; CI 0.0-1.9) in the Congested players than Controls, indicating a possible negative effect of fixture congestion. There were no effects on sprint and jump performance. The change in plasma (P)-Urea was greater in Congested players than controls (effect size 1.3; CI 0.3-2.2). The effects on other blood variables were either non-existing/trivial, or unclear. Altogether, physical fitness and immune function were not compromised by match congestion, yet some indices of physiological stress and muscle damage were still evident.

Free-Suspension Residual Flexibility Testing of Space Station Pathfinder: Comparison to Fixed-Base Results

NASA Technical Reports Server (NTRS)

Tinker, Michael L.

1998-01-01

Application of the free-suspension residual flexibility modal test method to the International Space Station Pathfinder structure is described. The Pathfinder, a large structure of the general size and weight of Space Station module elements, was also tested in a large fixed-base fixture to simulate Shuttle Orbiter payload constraints. After correlation of the Pathfinder finite element model to residual flexibility test data, the model was coupled to a fixture model, and constrained modes and frequencies were compared to fixed-base test. modes. The residual flexibility model compared very favorably to results of the fixed-base test. This is the first known direct comparison of free-suspension residual flexibility and fixed-base test results for a large structure. The model correlation approach used by the author for residual flexibility data is presented. Frequency response functions (FRF) for the regions of the structure that interface with the environment (a test fixture or another structure) are shown to be the primary tools for model correlation that distinguish or characterize the residual flexibility approach. A number of critical issues related to use of the structure interface FRF for correlating the model are then identified and discussed, including (1) the requirement of prominent stiffness lines, (2) overcoming problems with measurement noise which makes the antiresonances or minima in the functions difficult to identify, and (3) the use of interface stiffness and lumped mass perturbations to bring the analytical responses into agreement with test data. It is shown that good comparison of analytical-to-experimental FRF is the key to obtaining good agreement of the residual flexibility values.

Computer aided fixture design - A case based approach

NASA Astrophysics Data System (ADS)

Tanji, Shekhar; Raiker, Saiesh; Mathew, Arun Tom

2017-11-01

Automated fixture design plays important role in process planning and integration of CAD and CAM. An automated fixture setup design system is developed where when fixturing surfaces and points are described allowing modular fixture components to get automatically select for generating fixture units and placed into position with satisfying assembled conditions. In past, various knowledge based system have been developed to implement CAFD in practice. In this paper, to obtain an acceptable automated machining fixture design, a case-based reasoning method with developed retrieval system is proposed. Visual Basic (VB) programming language is used in integrating with SolidWorks API (Application programming interface) module for better retrieval procedure reducing computational time. These properties are incorporated in numerical simulation to determine the best fit for practical use.

Apparatus for measuring the finite load-deformation behavior of a sheet of epithelial cells cultured on a mesoscopic freestanding elastomer membrane.

PubMed

Selby, John C; Shannon, Mark A

2007-09-01

Details are given for the design, calibration, and operation of an apparatus for measuring the finite load-deformation behavior of a sheet of living epithelial cells cultured on a mesoscopic freestanding elastomer membrane, 10 microm thick and 5 mm in diameter. Although similar in concept to bulge tests used to investigate the mechanical properties of micromachined thin films, cell-elastomer composite diaphragm inflation tests pose a unique set of experimental challenges. Composite diaphragm (CD) specimens are extremely compliant (E<50 kPa), experience large displacements when subject to small inflation pressures (approximately 100 Pa), and must be continuously immersed in a bath of liquid culture medium during the acquisition of load-deformation measurements. Given these considerations, we have constructed an inflation apparatus consisting of an air-piston-cylinder pump integrated with a modular specimen mounting fixture that constitutes a horizontally semi-infinite reservoir of liquid culture medium. In a deformation-controlled inflation test, pressurized air is used to inflate a CD specimen into the liquid reservoir with minimum disturbance of the liquid-air interface. Piston displacements and absolute pump chamber air pressures are utilized as feedback to cycle the displaced (or inflated) CD volume V in a 0.05 Hz triangular or sinusoidal wave form (V(MIN)=0 microl, V(MAX)

Comparison of the Pullout Strength of Different Pedicle Screw Designs and Augmentation Techniques in an Osteoporotic Bone Model.

PubMed

Kiyak, Gorkem; Balikci, Tevfik; Heydar, Ahmed Majid; Bezer, Murat

2018-02-01

Mechanical study. To compare the pullout strength of different screw designs and augmentation techniques in an osteoporotic bone model. Adequate bone screw pullout strength is a common problem among osteoporotic patients. Various screw designs and augmentation techniques have been developed to improve the biomechanical characteristics of the bone-screw interface. Polyurethane blocks were used to mimic human osteoporotic cancellous bone, and six different screw designs were tested. Five standard and expandable screws without augmentation, eight expandable screws with polymethylmethacrylate (PMMA) or calcium phosphate augmentation, and distal cannulated screws with PMMA and calcium phosphate augmentation were tested. Mechanical tests were performed on 10 unused new screws of each group. Screws with or without augmentation were inserted in a block that was held in a fixture frame, and a longitudinal extraction force was applied to the screw head at a loading rate of 5 mm/min. Maximum load was recorded in a load displacement curve. The peak pullout force of all tested screws with or without augmentation was significantly greater than that of the standard pedicle screw. The greatest pullout force was observed with 40-mm expandable pedicle screws with four fins and PMMA augmentation. Augmented distal cannulated screws did not have a greater peak pullout force than nonaugmented expandable screws. PMMA augmentation provided a greater peak pullout force than calcium phosphate augmentation. Expandable pedicle screws had greater peak pullout forces than standard pedicle screws and had the advantage of augmentation with either PMMA or calcium phosphate cement. Although calcium phosphate cement is biodegradable, osteoconductive, and nonexothermic, PMMA provided a significantly greater peak pullout force. PMMA-augmented expandable 40-mm four-fin pedicle screws had the greatest peak pullout force.

Sensing sheets based on large area electronics for fatigue crack detection

NASA Astrophysics Data System (ADS)

Yao, Yao; Glisic, Branko

2015-03-01

Reliable early-stage damage detection requires continuous structural health monitoring (SHM) over large areas of structure, and with high spatial resolution of sensors. This paper presents the development stage of prototype strain sensing sheets based on Large Area Electronics (LAE), in which thin-film strain gauges and control circuits are integrated on the flexible electronics and deposited on a polyimide sheet that can cover large areas. These sensing sheets were applied for fatigue crack detection on small-scale steel plates. Two types of sensing-sheet interconnects were designed and manufactured, and dense arrays of strain gauge sensors were assembled onto the interconnects. In total, four (two for each design type) strain sensing sheets were created and tested, which were sensitive to strain at virtually every point over the whole sensing sheet area. The sensing sheets were bonded to small-scale steel plates, which had a notch on the boundary so that fatigue cracks could be generated under cyclic loading. The fatigue tests were carried out at the Carleton Laboratory of Columbia University, and the steel plates were attached through a fixture to the loading machine that applied cyclic fatigue load. Fatigue cracks then occurred and propagated across the steel plates, leading to the failure of these test samples. The strain sensor that was close to the notch successfully detected the initialization of fatigue crack and localized the damage on the plate. The strain sensor that was away from the crack successfully detected the propagation of fatigue crack based on the time history of measured strain. Overall, the results of the fatigue tests validated general principles of the strain sensing sheets for crack detection.

An evaluation of the Iosipescu specimen for composite materials shear property measurement

NASA Technical Reports Server (NTRS)

Morton, J.; Ho, H.; Tsai, M. Y.; Farley, G. L.

1992-01-01

A detailed evaluation of the suitability of the Iosipescu specimen tested in the modified Wyoming fixture is presented. A linear finite element model of the specimen is used to assess the uniformity of the shear stress field in the vicinity of the notch, and demonstrate the effect of the nonuniform stress field upon strain gage measurements used for the determination of composite shear moduli. Based upon test results from graphite-epoxy laminates, the proximity of the load introduction point to the test section and the material orthotropy greatly influence the individual gage readings, however, shear modulus determination is not significantly affected by the lack of pure shear. Correction factors are needed to allow for the nonuniformity of the strain field and the use of the average shear stress in the shear modulus evaluation. The correction factors are determined for the region occupied by the strain gage rosette. A comparison of the strain gage readings from one surface of a specimen with corresponding data from moire interferometry on the opposite face documented an extreme sensitivity of some fiber orientations to eccentric loading which induced twisting and spurious shear stress-strain curves. The discovery of specimen twisting explains the apparently inconsistent shear property data found in the literature. Recommendations for improving the reliability and accuracy of the shear modulus values are made, and the implications for shear strength measurement discussed.

The Effects of Compressive Preloads on the Compression-After-Impact Strength of Carbon/Epoxy

NASA Technical Reports Server (NTRS)

Nettles, Alan T.

1994-01-01

A fixture to apply compressive loads to composite specimens during an impact event was used to assess the effect of prestresses on the compression-after-impact (CAI) strength of 16 ply quasi-isotropic carbon/epoxy test coupons. Advanced design of experiments techniques were used to evaluate a range of prestresses and impact energies on two material systems, T300/934 and IM7/8551-7. An instrumented drop tower supplied impact energies between 1 and 9 Joules for the T300/934 material and between 4 and 16 Joules for the IM7/8551-7 material. The prestress values varied between a low of 5.7 Wa and a high of 287 NDa. Results showed some change in CAI strength that could be attributed to the prestresses on the specimens.

Vacuum die attach for integrated circuits

DOEpatents

Schmitt, E.H.; Tuckerman, D.B.

1991-09-10

A thin film eutectic bond for attaching an integrated circuit die to a circuit substrate is formed by coating at least one bonding surface on the die and substrate with an alloying metal, assembling the die and substrate under compression loading, and heating the assembly to an alloying temperature in a vacuum. A very thin bond, 10 microns or less, which is substantially void free, is produced. These bonds have high reliability, good heat and electrical conduction, and high temperature tolerance. The bonds are formed in a vacuum chamber, using a positioning and loading fixture to compression load the die, and an IR lamp or other heat source. For bonding a silicon die to a silicon substrate, a gold silicon alloy bond is used. Multiple dies can be bonded simultaneously. No scrubbing is required. 1 figure.

Vacuum die attach for integrated circuits

DOEpatents

Schmitt, Edward H.; Tuckerman, David B.

1991-01-01

A thin film eutectic bond for attaching an integrated circuit die to a circuit substrate is formed by coating at least one bonding surface on the die and substrate with an alloying metal, assembling the die and substrate under compression loading, and heating the assembly to an alloying temperature in a vacuum. A very thin bond, 10 microns or less, which is substantially void free, is produced. These bonds have high reliability, good heat and electrical conduction, and high temperature tolerance. The bonds are formed in a vacuum chamber, using a positioning and loading fixture to compression load the die, and an IR lamp or other heat source. For bonding a silicon die to a silicon substrate, a gold silicon alloy bond is used. Multiple dies can be bonded simultaneously. No scrubbing is required.

Influence of preparation depths on the fracture load of customized zirconia abutments with titanium insert.

PubMed

Joo, Han-Sung; Yang, Hong-So; Park, Sang-Won; Kim, Hyun-Seung; Yun, Kwi-Dug; Ji, Min-Kyung; Lim, Hyun-Pil

2015-06-01

This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging. Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a 4.5×10 mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: 5-55℃, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression. The fracture loads were 539.28 ± 63.11 N (N5), 406.56 ± 28.94 N (N7), 366.66 ± 30.19 N (N9), 392.61 ± 50.57 N (A5), 317.94 ± 30.05 N (A7), and 292.74 ± 37.15 N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05). The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly.

Influence of preparation depths on the fracture load of customized zirconia abutments with titanium insert

PubMed Central

Joo, Han-Sung; Yang, Hong-So; Park, Sang-Won; Kim, Hyun-Seung; Yun, Kwi-Dug; Ji, Min-Kyung

2015-01-01

PURPOSE This study evaluated the fracture load of customized zirconia abutments with titanium insert according to preparation depths, with or without 5-year artificial aging. MATERIALS AND METHODS Thirty-six identical lithium disilicate crowns (IPS e.max press) were fabricated to replace a maxillary right central incisor and cemented to the customized zirconia abutment with titanium insert on a 4.5×10 mm titanium fixture. Abutments were fabricated with 3 preparation depths (0.5 mm, 0.7 mm, and 0.9 mm). Half of the samples were then processed using thermocycling (temperature: 5-55℃, dwelling time: 120s) and chewing simulation (1,200,000 cycles, 49 N load). All specimens were classified into 6 groups depending on the preparation depth and artificial aging (non-artificial aging groups: N5, N7, N9; artificial aging groups: A5, A7, A9). Static load was applied at 135 degrees to the implant axis in a universal testing machine. Statistical analyses of the results were performed using 1-way ANOVA, 2-way ANOVA, independent t-test and multiple linear regression. RESULTS The fracture loads were 539.28 ± 63.11 N (N5), 406.56 ± 28.94 N (N7), 366.66 ± 30.19 N (N9), 392.61 ± 50.57 N (A5), 317.94 ± 30.05 N (A7), and 292.74 ± 37.15 N (A9). The fracture load of group N5 was significantly higher than those of group N7 and N9 (P<.017). Consequently, the fracture load of group A5 was also significantly higher than those of group A7 and A9 (P<.05). After artificial aging, the fracture load was significantly decreased in all groups with various preparation depths (P<.05). CONCLUSION The fracture load of a single anterior implant restored with lithium disilicate crown on zirconia abutment with titanium insert differed depending on the preparation depths. After 5-year artificial aging, the fracture loads of all preparation groups decreased significantly. PMID:26140169

KSC-2010-5310

NASA Image and Video Library

2010-10-27

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, the 600-Ton Test Fixture outside the Launch Equipment Test Facility conducts a 500,000-pound pull test of a bridge crane lifting element, which is used to lift space shuttles in the Vehicle Assembly Building. The fixture proofload tests, in tension and compression, a variety of ground support equipment, including slings, lifting beams and other critical lifting hardware that require periodic proofloading. Since 1977, the facility has supported NASA’s Launch Services, shuttle, International Space Station, and Constellation programs, as well as commercial providers. The facility recently underwent a major upgrade to support even more programs, projects and customers. It houses a 6,000-square-foot high bay, cable fabrication and molding shop, pneumatics shop, machine and weld shop and full-scale control room. Outside, the facility features a water flow test loop, vehicle motion simulator, launch simulation towers and a cryogenic system. Photo credit: NASA/Jim Grossmann

KSC-2010-5308

NASA Image and Video Library

2010-10-27

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, the 600-Ton Test Fixture outside the Launch Equipment Test Facility is prepared to conduct a 500,000-pound pull test of a bridge crane lifting element, which is used to lift space shuttles in the Vehicle Assembly Building. The fixture proofload tests, in tension and compression, a variety of ground support equipment, including slings, lifting beams and other critical lifting hardware that require periodic proofloading. Since 1977, the facility has supported NASA’s Launch Services, shuttle, International Space Station, and Constellation programs, as well as commercial providers. The facility recently underwent a major upgrade to support even more programs, projects and customers. It houses a 6,000-square-foot high bay, cable fabrication and molding shop, pneumatics shop, machine and weld shop and full-scale control room. Outside, the facility features a water flow test loop, vehicle motion simulator, launch simulation towers and a cryogenic system. Photo credit: NASA/Jim Grossmann

KSC-2010-5311

NASA Image and Video Library

2010-10-27

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, the 600-Ton Test Fixture outside the Launch Equipment Test Facility conducts a 500,000-pound pull test of a bridge crane lifting element, which is used to lift space shuttles in the Vehicle Assembly Building. The fixture proofload tests, in tension and compression, a variety of ground support equipment, including slings, lifting beams and other critical lifting hardware that require periodic proofloading. Since 1977, the facility has supported NASA’s Launch Services, shuttle, International Space Station, and Constellation programs, as well as commercial providers. The facility recently underwent a major upgrade to support even more programs, projects and customers. It houses a 6,000-square-foot high bay, cable fabrication and molding shop, pneumatics shop, machine and weld shop and full-scale control room. Outside, the facility features a water flow test loop, vehicle motion simulator, launch simulation towers and a cryogenic system. Photo credit: NASA/Jim Grossmann

KSC-2010-5309

NASA Image and Video Library

2010-10-27

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, the 600-Ton Test Fixture outside the Launch Equipment Test Facility conducts a 500,000-pound pull test of a bridge crane lifting element, which is used to lift space shuttles in the Vehicle Assembly Building. The fixture proofload tests, in tension and compression, a variety of ground support equipment, including slings, lifting beams and other critical lifting hardware that require periodic proofloading. Since 1977, the facility has supported NASA’s Launch Services, shuttle, International Space Station, and Constellation programs, as well as commercial providers. The facility recently underwent a major upgrade to support even more programs, projects and customers. It houses a 6,000-square-foot high bay, cable fabrication and molding shop, pneumatics shop, machine and weld shop and full-scale control room. Outside, the facility features a water flow test loop, vehicle motion simulator, launch simulation towers and a cryogenic system. Photo credit: NASA/Jim Grossmann

Effects of heat and moisture on fiberglass composite materials in the load carrying and non-load carrying conditions

NASA Astrophysics Data System (ADS)

McClurg, Jack Albert

The objective set forth in this study was to thoroughly document the effects of heat, moisture, and loading conditions on a variety of pultruded unidirectional fiberglass reinforced composite materials. This study incorporated the use of two environmental control chambers and two water immersion tanks in order to provide the necessary range of environmental exposure conditions. A set of specially designed stainless steel loading fixtures was produced in order to introduce the factor of external loading of the specimens while exposed to the predetermined environmental condition and how that would affect the mechanical and physical properties in question. The properties of interest were the flexural strength (determined using the three-point flexural bending method), flexural modulus (determined using the three-point flexural bending method), and glass transition temperature of the material (determined using differential scanning calorimetry). Other data that was noted during the conditioning and testing of the specimens was the break type (flexural tension, compression, shear, etc...), the change in dimensions (prior to exposure vs. after exposure), and the change in weight (prior to exposure vs. after exposure). Using all of the information that was obtained from this study, a more detailed understanding of how and why fiberglass reinforced materials react the way they do when exposed to moisture and elevated temperature was drawn. This study is different from most others in that it explores the interactions of three independent variables (heat, moisture, and loading condition) on three different fiberglass reinforced composite systems (epoxy, vinylester, and polyester resin).

Some further developments in the dynamic modelling and control of the large angle magnetic suspension test fixture

NASA Technical Reports Server (NTRS)

Britcher, Colin P.; Foster, Lucas E.

1994-01-01

A small-scale laboratory magnetic suspension system, the Large Angle Magnetic Suspension Test Fixture (LAMSTF) has been constructed at NASA Langley Research Center. This paper first presents some recent developments in the mathematical modelling of the system, particularly in the area of eddy current effects. It is shown that these effects are significant, but may be amenable to modelling and measurement. Next, a theoretical framework is presented, together with a comparison of computed and experimental data. Finally, some control aspects are discussed, together with illustration that the major design objective of LAMSTF - a controlled 360 deg rotation about the vertical axis, has been accomplished.

Comparison of the stability of various internal fixators used in the treatment of osteochondritis dissecans--a mechanical model.

PubMed

Morelli, Moreno; Poitras, Philippe; Grimes, Valentine; Backman, David; Dervin, Geoffrey

2007-04-01

The purpose of this study was to determine what characteristics of fixation devices used in the treatment of osteochondritis dissecans (OCD) contribute to improved stability to resist shear loading. An OCD model was designed using rigid polyurethane foam. Each specimen consisted of two components, an osteochondral fragment and a corresponding defect. A total of 40 specimens were prepared and assigned to one of four groups: control (no extrinsic stabilizer); two 2-mm-diameter Kirschner wires (K-wires), 40 mm in length; one threaded washer and a 28-mm screw; and one threaded washer and a 38 mm screw. Each specimen was mounted onto an Iosipescu shear test fixture and subjected to shear loads at a pseudo-static displacement rate of 0.075 mm/s. All groups demonstrated some stability; controls were significantly less stable than all other groups. The group with the threaded washer and 38-mm screw demonstrated the greatest stability (p < 0.001), and no difference was noted between the K-wire and 28-mm screw groups. These results suggest that, in this OCD model, friction conferred some intrinsic stability to resist loads in shear. However, stability was improved with the use of long implants that compressed the fragments together.

Postbuckling behavior of axially compressed graphite-epoxy cylindrical panels with circular holes

NASA Technical Reports Server (NTRS)

Knight, N. F., Jr.; Starnes, J. H., Jr.

1984-01-01

The results of an experimental and analytical study of the effects of circular holes on the postbuckling behavior of graphite-epoxy cylindrical panels loaded in axial compression are presented. The STAGSC-1 general shell analysis computer code is used to determine the buckling and postbuckling response of the panels. The loaded, curved ends of the specimens were clamped by fixtures and the unloaded, straight edges were simply supported by knife-edge restraints. The panels are loaded by uniform end shortening to several times the end shortening at buckling. The unstable equilibrium path of the postbuckling response is obtained analytically by using a method based on controlling an equilibrium-path-arc-length parameter instead of the traditional load parameter. The effects of hole diameter, panel radius, and panel thickness on postbuckling response are considered in the study. Experimental results are compared with the analytical results and the failure characteristics of the graphite-epoxy panels are described.

Development of sacrificial support fixture using deflection analysis

NASA Astrophysics Data System (ADS)

Ramteke, Ashwini M.; Ashtankar, Kishor M.

2018-04-01

Sacrificial support fixtures are the structures used to hold the part during machining while rotating the part about the fourth axis of CNC machining. In Four axis CNC machining part is held in a indexer which is rotated about the fourth axis of rotation. So using traditional fixturing devices to hold the part during machining such as jigs, v blocks and clamping plates needs a several set ups, manufacturing time which increase the cost associated with it. Since the part is rotated about the axis of rotation in four axis CNC machining so using traditional fixturing devices to hold the part while machining we need to reorient the fixture each time for particular orientation of part about the axis of rotation. So our proposed methodology of fixture design eliminates the cost associate with the complicated fixture design for customized parts which in turn reduces the time of manufacturing of the fixtures. But while designing the layout of the fixtures it is found out that the machining the part using four axis CNC machining the accurate machining of the part is directly proportional to the deflection produced in a part. So to machine an accurate part the deflection produced in a part should be minimum. We assume that the deflection produced in a part is a result of the deflection produced in a sacrificial support fixture while machining. So this paper provides the study of the deflection checking in a part machined using sacrificial support fixture by using FEA analysis.

Control of Superelastic Behavior of NiTi Wires Aided by Thermomechanical Treatment with Reference to Three-Point Bending

NASA Astrophysics Data System (ADS)

Shahmir, Hamed; Nili-Ahmadabadi, Mahmoud; Naghdi, Fariba; Habibi-Parsa, Mohammad; Haririan, Ismaeil

2014-04-01

The aim of this study is to investigate the effect of thermomechanical treatment on the superelastic behavior of a Ti-50.5 at.%Ni wire in terms of loading/unloading plateau, mechanical hysteresis, and permanent set to optimize these parameters for orthodontic applications. A new three-point bending fixture, oral cavity configuration three-point bending (OCTPB) test, was utilized to determine the superelastic property in clinical condition, and therefore, the tests were carried out at 37 °C. The results indicate that the thermomechanical treatment is crucial for thermal transformation and mechanically induced transformation characteristics of the wire. Annealing of thermomechanically treated specimens at 300 and 400 °C for 1/2 and 1 h leads to good superelasticity for orthodontic applications. However, the best superelasticity at body temperature is obtained after annealing at 300 °C for 1/2 h with regard to low and constant unloading force and minimum permanent set.

High-output LED-based light engine for profile lighting fixtures with high color uniformity using freeform reflectors.

PubMed

Gadegaard, Jesper; Jensen, Thøger Kari; Jørgensen, Dennis Thykjær; Kristensen, Peter Kjær; Søndergaard, Thomas; Pedersen, Thomas Garm; Pedersen, Kjeld

2016-02-20

In the stage lighting and entertainment market, light engines (LEs) for lighting fixtures are often based on high-intensity discharge (HID) bulbs. Switching to LED-based light engines gives possibilities for fast switching, additive color mixing, a longer lifetime, and potentially, more energy-efficient systems. The lumen output of a single LED is still not sufficient to replace an HID source in high-output profile fixtures, but combining multiple LEDs can create an LE with a similar output, but with added complexity. This paper presents the results of modeling and testing such a light engine. Custom ray-tracing software was used to design a high-output red, green and blue LED-based light engine with twelve CBT-90 LEDs using a dual-reflector principle. The simulated optical system efficiency was 0.626 with a perfect (R=1) reflector coating for light delivered on a target surface through the entire optical system. A profile lighting fixture prototype was created, and provided an output of 6744 lumen and an efficiency of 0.412. The lower efficiency was mainly due to a non-optimal reflector coating, and the optimized design is expected to reach a significantly higher efficiency.

46 CFR 111.75-20 - Lighting fixtures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Lighting Circuits and Protection § 111.75-20 Lighting fixtures. (a) The construction of each... connection box for a circuit other than the branch circuit supplying the fixture. (d) Lighting fixtures must...

Preparing Juno for Environmental Testing

NASA Image and Video Library

2010-12-16

NASA Juno spacecraft rests atop its rotation fixture awaiting transfer to a shipping crate prior to environmental testing; the large white square on the spacecraft right is largest of six microwave radiometer antennas, masked by protective covering.

Characterization of Viscoelastic Materials for Low-Magnitude Blast Mitigation

NASA Astrophysics Data System (ADS)

Bartyczak, Susan; Mock, Willis

2013-06-01

Recent preliminary research indicates that exposure to low amplitude blast waves, such as from IED detonation or multiple firings of a weapon, causes damage to brain tissue resulting in Traumatic Brain Injury (TBI) and Post Traumatic Stress Disorder (PTSD). Current combat helmets are not sufficiently protecting warfighters from this danger and the effects are debilitating, costly, and long-lasting. The objective of this research is to evaluate the blast mitigating behavior of current helmet materials and new materials designed for blast mitigation using a test fixture recently developed at the Naval Surface Warfare Center Dahlgren Division for use with an existing gas gun. A 40-mm-bore gas gun is used as a shock tube to generate blast waves (ranging from 5 to 30 psi) in a test fixture mounted at the gun muzzle. A fast opening valve is used to release helium gas from a breech which forms into a blast wave and impacts instrumented targets in the test fixture. Blast attenuation of selected materials is determined through the measurement of pressure and accelerometer data in front of and behind the target. Materials evaluated in this research include 6061-T6 aluminum, polyurea 1000, Styrofoam, and Sorbothane (durometer 50, shore 00). The experimental technique, calibration and checkout procedures, and results will be presented.

High-temperature strain cell for tomographic imaging

DOEpatents

MacDowell, Alastair A.; Nasiatka, James; Haboub, Abdel; Ritchie, Robert O.; Bale, Hrishikesh A.

2015-06-16

This disclosure provides systems, methods, and apparatus related to the high temperature mechanical testing of materials. In one aspect, a method includes providing an apparatus. The apparatus may include a chamber. The chamber may comprise a top portion and a bottom portion, with the top portion and the bottom portion each joined to a window material. A first cooled fixture and a second cooled fixture may be mounted to the chamber and configured to hold the sample in the chamber. A plurality of heating lamps may be mounted to the chamber and positioned to heat the sample. The sample may be placed in the first and the second cooled fixtures. The sample may be heated to a specific temperature using the heating lamps. Radiation may be directed though the window material, the radiation thereafter interacting with the sample and exiting the chamber through the window material.

Optical fiber cable chemical stripping fixture

NASA Technical Reports Server (NTRS)

Kolasinski, John R. (Inventor); Coleman, Alexander M. (Inventor)

1995-01-01

An elongated fixture handle member is connected to a fixture body member with both members having interconnecting longitudinal central axial bores for the passage of an optical cable therethrough. The axial bore of the fixture body member, however, terminates in a shoulder stop for the outer end of a jacket of the optical cable covering both an optical fiber and a coating therefor, with an axial bore of reduced diameter continuing from the shoulder stop forward for a predetermined desired length to the outer end of the fixture body member. A subsequent insertion of the fixture body member including the above optical fiber elements into a chemical stripping solution results in a softening of the exposed external coating thereat which permits easy removal thereof from the optical fiber while leaving a desired length coated fiber intact within the fixture body member.

Development of a Ground-Based Analog to the Advanced Resistive Exercise Device Aboard the International Space Station

NASA Technical Reports Server (NTRS)

Newby, Nathaniel J.; Scott-Pandorf, M. M.; Caldwell, E.; DeWitt, J.K.; Fincke, R.; Peters, B.T.

2010-01-01

NASA and Wyle engineers constructed a Horizontal Exercise Fixture (HEF) that was patented in 2006. Recently modifications were made to HEF with the goal of creating a device that mimics squat exercise on the Advanced Resistive Exercise Device (ARED) and can be used by bed rest subjects who must remain supine during exercise. This project posed several engineering challenges, such as how best to reproduce the hip motions (we used a sled that allowed hip motion in the sagittal plane), how to counterweight the pelvis against gravity (we used a pulley and free-weight mechanism), and how to apply large loads (body weight plus squat load) to the shoulders while simultaneously supporting the back against gravity (we tested a standard and a safety bar that allowed movement in the subject s z-axis, both of which used a retractable plate for back support). METHODS An evaluation of the HEF was conducted with human subjects (3F, 3M), who performed sets of squat exercises of increasing load from 10-repetition maximum (RM) up to 1-RM. Three pelvic counterweight loads were tested along with each of the two back-support squat bars. Data collection included 3-dimensional ground reaction forces (GRF), muscle activation (EMG), body motion (video-based motion capture), and subjective comments. These data were compared with previous ground-based ARED study data. RESULTS All subjects in the evaluation were able to perform low- to high-loading squats on the HEF. Four of the 6 subjects preferred a pelvic counterweight equivalent to 60 percent of their body weight. Four subjects preferred the standard squat bar, whereas 2 female subjects preferred the safety bar. EMG data showed muscle activation in the legs and low back typical of squat motion. GRF trajectories and eccentric-concentric loading ratios were similar to ARED. CONCLUSION: Squat exercise performed on HEF approximated squat exercise on ARED.

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

Ton, My K.; Richman, Eric E.; Gilbride, Theresa L.

In August 2008 the Pacific Northwest National Laboratory (PNNL) conducted a light emitting diode (LED) residential lighting demonstration project for the U.S. Department of Energy (DOE), Office of Building Technologies, as part of DOE’s Solid State Lighting (SSL) Technology Demonstration Gateway Program. Two lighting technologies, an LED replacement for downlight lamps (bulbs) and an LED undercabinet lighting fixture, were tested in the demonstration which was conducted in two homes built for the 2008 Tour of Homes in Eugene, Oregon. The homes were built by the Lane County Home Builders Association (HBA), and Future B Homes. The Energy Trust of Oregonmore » (ETO) also participated in the demonstration project. The LED downlight product, the LR6, made by Cree LED Lighting Solutions acts as a screw-in replacement for incandescent and halogen bulbs in recessed can downlights. The second product tested is Phillips/Color Kinetics’ eW® Profile Powercore undercabinet fixture designed to mount under kitchen cabinets to illuminate the countertop and backsplash surfaces. Quantitative and qualitative measurements of light performance and electrical power usage were taken at each site before and after initially installed halogen and incandescent lamps were replaced with the LED products. Energy savings and simple paybacks were also calculated and builders who toured the homes were surveyed for their responses to the LED products. The LED downlight product drew 12 Watts of power, cutting energy use by 82% compared to the 65W incandescent lamp and by 84% compared to the 75W halogen lamp. The LED undercabinet fixture drew 10 watts, cutting energy use by 83% to 90% compared to the halogen product, which was tested at two power settings: a low power 60W setting and a high power 105W setting. The LED downlight consistently provided more light than the halogen and incandescent lamps in horizontal measurements at counter height and floor level. It also outperformed in vertical illuminance measurements taken on the walls, indicating better lateral dispersion of the light. The undercabinet fixture’s light output was midway between the low and high power halogen undercabinet fixture light outputs (35.8 foot candle versus 13.4 fc and 53.4 fc) but it produced a more uniform light (max/min ratio of 7.0 versus 10.8). The color correlated temperature (CCT, the blue or yellowness) of the LED light correlated well with the halogen and incandescent lights (2675 K vs 2700 K). The color rendering of the LED downlight also correlated well at 92 CRI compared to 100 CRI for the halogen and incandescent lamps. The LED undercabinet fixture had measures of 2880 K CCT and 71 CRI compared to the 2700 K and 100 CRI scores for the halogen undercabinet fixture. Builders who toured the homes were surveyed; they gave the LED downlight high marks for brightness, said the undercabinet improved shadows and glare and said both products improved overall visibility, home appearance, and home value. Paybacks on the LED downlight ranged from 7.6 years (assuming electricity cost of 11 c/kWh) to 13.5 years (at 5C/kWh). Paybacks on the LED undercabinet fixture in a new home ranged from 4.4 years (11c/kWh electricity) to 7.6 years (5c/kWh) based on product costs of $95 per LED downlight and $140 per LED undercabinet fixture at 3 hrs per day of usage for the downlight and 2 hrs per day for the undercabinet lighting.« less

The Ball Welding Bar: A New Solution for the Immediate Loading of Screw-Retained, Mandibular Fixed Full Arch Prostheses

PubMed Central

Bacchiocchi, Danilo

2017-01-01

Purpose To present a new intraoral welding technique, which can be used to manufacture screw-retained, mandibular fixed full-arch prostheses. Methods Over a 4-year period, all patients with complete mandibular edentulism or irreparably compromised mandibular dentition, who will restore the masticatory function with a fixed mandibular prosthesis, were considered for inclusion in this study. The “Ball Welding Bar” (BWB) technique is characterised by smooth prosthetic cylinders, interconnected by means of titanium bars which are adjustable in terms of distance from ball terminals and are inserted in the rotating rings of the cylinders. All the components are welded and self-posing. Results Forty-two patients (18 males; 24 females; mean age 64.2 ± 6.7 years) were enrolled and 210 fixtures were inserted to support 42 mandibular screw-retained, fixed full-arch prostheses. After two years of loading, 2 fixtures were lost, for an implant survival rate of 97.7%. Five implants suffered from peri-implant mucositis and 3 implants for peri-implantitis. Three of the prostheses (3/42) required repair for fracture (7.1%): the prosthetic success was 92.9%. Conclusions The BWB technique seems to represent a reliable technique for the fabrication of screw-retained mandibular fixed full-arch prostheses. This study was registered in the ISRCTN register with number ISRCTN71229338. PMID:28835752

Design and Calibration of a Flowfield Survey Rake for Inlet Flight Research

NASA Technical Reports Server (NTRS)

Flynn, Darin C.; Ratnayake, Nalin A.; Frederick, Michael

2009-01-01

The Propulsion Flight Test Fixture at the NASA Dryden Flight Research Center is a unique test platform available for use on NASA's F-15B aircraft, tail number 836, as a modular host for a variety of aerodynamics and propulsion research. For future flight data from this platform to be valid, more information must be gathered concerning the quality of the airflow underneath the body of the F-15B at various flight conditions, especially supersonic conditions. The flow angularity and Mach number must be known at multiple locations on any test article interface plane for measurement data at these locations to be valid. To determine this prerequisite information, flight data will be gathered in the Rake Airflow Gauge Experiment using a custom-designed flowfield rake to probe the airflow underneath the F-15B at the desired flight conditions. This paper addresses the design considerations of the rake and probe assembly, including the loads and stress analysis using analytical methods, computational fluid dynamics, and finite element analysis. It also details the flow calibration procedure, including the completed wind-tunnel test and posttest data reduction, calibration verification, and preparation for flight-testing.

Development and Realization of a Shock Wave Test on Expert Flap Qualification Model

NASA Astrophysics Data System (ADS)

De Fruytier, C.; Dell'Orco, F.; Ullio, R.; Gomiero, F.

2012-07-01

This paper presents the methodology and the results of the shock test campaign conducted by TAS-I and TAS ETCA to qualify the EXPERT Flap in regards of shock wave and acoustic load generated by pyrocord detonation at stages 2/3 separation phase of the EXPERT vehicle. The design concept of the open flap (manufactured by MT AEROSPACE) is a fully integral manufactured, four sided control surface, with an additional stiffening rib and flanges to meet the first eigenfrequency and the allowable deformation requirement with a minimum necessary mass. The objectives were to reproduce equivalent loading at test article level in terms of pulse duration, front pressure, front velocity and acoustic emission. The Thales Alenia Space ETCA pyrotechnic shock test device is usually used to produce high level shocks by performing a shock on a test fixture supporting the unit under test. In this case, the facility has been used to produce a shock wave, with different requested physical characteristics, directed to the unit under test. Different configurations have been tried on a dummy of the unit to test, following an empirical process. This unusual work has lead to the definition of a nominal set- up meeting the requested physical parameters. Two blast sensors have been placed to acquire the pressure around the flap. The distance between the two sensors has allowed estimating the front pressure velocity. Then, several locations have been selected to acquire the acceleration responses on the unit when it was submitted to this environment. Additionally, a “standard” shock test has been performed on this model. The qualification of the flap, in regards of shock environment, has been successfully conducted.

Industrial surface coatings: Wood furniture and fixtures emission inventory development. Final report

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

Anex, R.P.; Lund, J.R.; Chang, D.P.Y.

1998-06-01

The purpose of this study is to update the methods for estimating emissions from the industrial coatings subcategory of wood furniture and fixtures. The wood furniture and fixture industry encompasses the manufacture of diverse products including cabinets, office furniture, store fixtures, and residential furniture. Specific objectives of this work are to: (1) estimate the amount of coating used in the industrial surface coating of wood furniture and fixtures; (2) develop emissions factors for each coating application category; (3) estimate variability of both coating use and emission factors; and (4) specify a source of information and method to revise and updatemore » the industrial coating of wood furniture and fixtures emission inventory.« less

16 CFR § 1203.15 - Positional stability test (roll-off resistance).

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Positional stability test (roll-off... stability test (roll-off resistance). (a) Test equipment. (1) Headforms. The test headforms shall comply with the dimensions of the full chin ISO reference headforms sizes A, E, J, M, and O. (2) Test fixture...

Alignment Fixtures For Vacuum-Plasma-Spray Gun

NASA Technical Reports Server (NTRS)

Woodford, William H.; Mckechnie, Timothy N.; Power, Christopher A.; Daniel, Ronald L., Jr.

1993-01-01

Fixtures for alignment of vacuum-plasma-spray guns built. Each fixture designed to fit specific gun and holds small, battery-powered laser on centerline of gun. Laser beam projects small red dot where centerline intersects surface of workpiece to be sprayed. After laser beam positioned on surface of workpiece, fixture removed from gun and spraying proceeds.

Improving Beamline X-ray Optics by Analyzing the Damage to Crystallographic Structure

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

Zientek, John; Maj, Jozef; Navrotski, Gary

2015-01-02

The mission of the X-ray Characterization Laboratory in the X-ray Science Division (XSD) at the Advanced Photon Source (APS) is to support both the users and the Optics Fabrication Facility that produces high performance optics for synchrotron X-ray beamlines. The Topography Test Unit (TTU) in the X-ray Lab has been successfully used to characterize diffracting crystals and test monochromators by quantifying residual surface stresses. This topographic method has also been adapted for testing standard X-ray mirrors, characterizing concave crystal optics and in principle, can be used to visualize residual stresses on any optic made from single crystalline material. The TTUmore » has been instrumental in quantitatively determining crystal mounting stresses which are mechanically induced by positioning, holding, and cooling fixtures. It is this quantitative aspect that makes topography so useful since the requirements and responses for crystal optics and X-ray mirrors are quite different. In the case of monochromator crystals, even small residual or induced stresses, on the order of tens of kPa, can cause detrimental distortions to the perfect crystal rocking curves. Mirrors, on the other hand, are much less sensitive to induced stresses where stresses that are an order of magnitude greater can be tolerated. This is due to the fact that the surface rather than the lattice-spacing determines a mirror’s performance. For the highly sensitive crystal optics, it is essential to measure the in-situ rocking curves using topographs as mounting fixtures are adjusted. In this way, high heat-load monochromator crystals can be successfully mounted with minimum stress. Topographical analysis has been shown to be a highly effective method to visualize and quantify the distribution of stresses, to help identify methods that mitigate stresses, and most notably to improve diffractive crystal optic rocking curves.« less

Large angle magnetic suspension test fixture

NASA Technical Reports Server (NTRS)

Britcher, Colin P.

1993-01-01

Progress made under the subject grant in the period from 1 Nov. 1992 to 31 May 1993 is presented. The research involves the continued development of the Large Angle Magnetic Suspension Test Fixture (LAMSTF) and also the recommissioning of an additional piece of exisiting hardware. During the period in question, the initial configuration of LAMSTF was completed and made routinely and reliably operational. A digital phase advance controller was completed and documented. The goal of a controlled 360 deg rotation was achieved. Work started on the recommissioning of the Annular Suspension and Pointing System (ASPS). Work completed during the report period included: modeling; position sensing; controller; support of the Second International Symposium on Magnetic Suspension Technology; and recommissioning of the Annular Suspension and Pointing System.

Testing methods and techniques: Environmental testing: A compilation

NASA Technical Reports Server (NTRS)

1971-01-01

Various devices and techniques are described for testing hardware and components in four special environments: low temperature, high temperature, high pressure, and vibration. Items ranging from an automatic calibrator for pressure transducers to a fixture for testing the susceptibility of materials to ignition by electric spark are included.

3D finite element analysis of changes in stress levels and distributions for an osseointegrated implant after vertical bone loss.

PubMed

Yoon, Kyung-Ho; Kim, Su-Gwan; Lee, Jeong-Hoon; Suh, Seung-Woo

2011-10-01

The effect of stress levels and distributions around the internal nonsubmerged type implants after vertical bone resorption was investigated in this study. An HSII implant was placed in 4 cylindrical alveolar bone models with differing degrees of thread exposures. The load applied to each implant was von Mises stress and principal stress, 250 N in axial direction and 30 degrees lateral pressure. The difference in the load between the bone and the connective portion of the implant was obtained using ANSYS analysis. Bone loss in the cervical area of the implant was more obvious under lateral pressure. When more threads were exposed, bone level decreased and the maximum load applied on the fixture increased. It was concluded that higher bone level has a biomechanical advantage with respect to stress concentration.

Fracture Testing of Large-Scale Thin-Sheet Aluminum Alloy (MS Word file)

DOT National Transportation Integrated Search

1996-02-01

Word Document; A series of fracture tests on large-scale, precracked, aluminum alloy panels were carried out to examine and characterize the process by which cracks propagate and link up in this material. Extended grips and test fixtures were special...

1000541

NASA Image and Video Library

2010-04-13

TATHAN COFFEE (EM10 MATERIALS TEST ENGINEER, JACOBS ESTS GROUP/JTI) ADJUSTS A UNIQUE MECHANICAL TEST SETUP THAT MEASURES STRAIN ON A SINGLE SAMPLE, USING TWO DIFFERENT TECHNIQUES AT THE SAME TIME. THE TEST FIXTURE HOLDS A SPECIMEN THAT REPRESENTS A LIQUID OXYGEN (LOX) BEARING FROM THE J2-X ENGINE

Further Investigations of Control Surface Seals for the X-38 Re-Entry Vehicle

NASA Technical Reports Server (NTRS)

Dunlap, Patrick H., Jr.; Steinetz, Bruce M.; Curry, Donald M.; Newquist, Charles W.; Verzemnieks, Juris

2001-01-01

NASA is currently developing the X-38 vehicle that will be used to demonstrate the technologies required for a potential crew return vehicle (CRV) for the International Space Station. This vehicle would serve both as an ambulance for medical emergencies and as an evacuation vehicle for the Space Station. Control surfaces on the X-38 (body flaps and rudder/fin assemblies) require high temperature seals to limit hot gas ingestion and transfer of heat to underlying low-temperature structures to prevent over-temperature of these structures and possible loss of the vehicle. NASAs Johnson Space Center (JSC) and Glenn Research Center (GRC) are working together to develop and evaluate seals for these control surfaces. This paper presents results for compression. flow, scrub, and arc jet tests conducted on the baseline X-38 rudder/fin seal design. Room temperature seal compression tests were performed at low compression levels to determine load versus linear compression, preload. contact area, stiffness. and resiliency characteristics under low load conditions. For all compression levels that were tested, unit loads and contact pressures for the seals were below the 5 lb/in. and 10 psi limits required to limit the loads on the adjoining Shuttle thermal tiles that the seals will contact. Flow rates through an unloaded (i.e. 0% compression) double arrangement were twice those of a double seal compressed to the 20% design compression level. The seals survived an ambient temperature 1000 cycle scrub test over relatively rough Shuttle tile surfaces. The seals were able to disengage and re-engage the edges of the rub surface tiles while being scrubbed over them. Arc jet tests were performed to experimentally determine anticipated seal temperatures for representative flow boundary conditions (pressures and temperatures) under simulated vehicle re-entry conditions. Installation of a single seat in the gap of the test fixture caused a large temperature drop (1710 F) across the seal location as compared to an open gap condition (140 F) confirming the need for seals in the rudder/fin gap location. The seal acted as an effective thermal barrier limiting heat convection through the seal gap and minimizing temperature increases downstream of the seal during maximum heating conditions.

Determination of Parachute Joint Factors using Seam and Joint Testing

NASA Technical Reports Server (NTRS)

Mollmann, Catherine

2015-01-01

This paper details the methodology for determining the joint factor for all parachute components. This method has been successfully implemented on the Capsule Parachute Assembly System (CPAS) for the NASA Orion crew module for use in determining the margin of safety for each component under peak loads. Also discussed are concepts behind the joint factor and what drives the loss of material strength at joints. The joint factor is defined as a "loss in joint strength...relative to the basic material strength" that occurs when "textiles are connected to each other or to metals." During the CPAS engineering development phase, a conservative joint factor of 0.80 was assumed for each parachute component. In order to refine this factor and eliminate excess conservatism, a seam and joint testing program was implemented as part of the structural validation. This method split each of the parachute structural joints into discrete tensile tests designed to duplicate the loading of each joint. Breaking strength data collected from destructive pull testing was then used to calculate the joint factor in the form of an efficiency. Joint efficiency is the percentage of the base material strength that remains after degradation due to sewing or interaction with other components; it is used interchangeably with joint factor in this paper. Parachute materials vary in type-mainly cord, tape, webbing, and cloth -which require different test fixtures and joint sample construction methods. This paper defines guidelines for designing and testing samples based on materials and test goals. Using the test methodology and analysis approach detailed in this paper, the minimum joint factor for each parachute component can be formulated. The joint factors can then be used to calculate the design factor and margin of safety for that component, a critical part of the design verification process.

Modification of Fixture Mount to be Used as an Impression Coping in Closely Placed Implants

PubMed Central

Jain, Anoop; K, Cauvery; Kumar, Pawan; Havale, Raghavendra

2014-01-01

An implant-level impression is often desired for designing and fabricating an implant-supported fixed restoration. This clinical report describes the use of modified press-fit metal implant fixture mount as an impression coping for making an impression of closely placed implants. The fixture mount is easier to manipulate, time saving and more comfortable for both the clinician and patient because the implant fixture mount is connected to the implant by pressing on instead of screwing. As compared to plastic press fit impression coping, metal fixture mount will not distort when modification of fixture mount are required in convergently or closely placed implants. It has the advantage of both the open-tray and closed-tray implant impression techniques. PMID:24959520

Modification of Fixture Mount to be Used as an Impression Coping in Closely Placed Implants.

PubMed

Mahoorkar, Sudhindra; Jain, Anoop; K, Cauvery; Kumar, Pawan; Havale, Raghavendra

2014-04-01

An implant-level impression is often desired for designing and fabricating an implant-supported fixed restoration. This clinical report describes the use of modified press-fit metal implant fixture mount as an impression coping for making an impression of closely placed implants. The fixture mount is easier to manipulate, time saving and more comfortable for both the clinician and patient because the implant fixture mount is connected to the implant by pressing on instead of screwing. As compared to plastic press fit impression coping, metal fixture mount will not distort when modification of fixture mount are required in convergently or closely placed implants. It has the advantage of both the open-tray and closed-tray implant impression techniques.

Composite Cryotank Technologies and Development 2.4 and 5.5M out of Autoclave Tank Test Results

NASA Technical Reports Server (NTRS)

Jackson, Justin R.; Vickers, John; Fikes, John

2015-01-01

The Composite Cryotank Technologies and Demonstration (CCTD) project substantially matured composite, cryogenic propellant tank technology. The project involved the design, analysis, fabrication, and testing of large-scale (2.4-m-diameter precursor and 5.5-m-diameter) composite cryotanks. Design features included a one-piece wall design that minimized tank weight, a Y-joint that incorporated an engineered material to alleviate stress concentration under combined loading, and a fluted core cylindrical section that inherently allows for venting and purging. The tanks used out-of-autoclave (OoA) cured graphite/epoxy material and processes to enable large (up to 10-m-diameter) cryotank fabrication, and thin-ply prepreg to minimize hydrogen permeation through tank walls. Both tanks were fabricated at Boeing using automated fiber placement on breakdown tooling. A fluted core skirt that efficiently carried axial loads and enabled hydrogen purging was included on the 5.5-m-diameter tank. Ultrasonic inspection was performed, and a structural health monitoring system was installed to identify any impact damage during ground processing. The precursor and 5.5-m-diameter tanks were tested in custom test fixtures at the National Aeronautics and Space Administration Marshall Space Flight Center. The testing, which consisted of a sequence of pressure and thermal cycles using liquid hydrogen, was successfully concluded and obtained valuable structural, thermal, and permeation performance data. This technology can be applied to a variety of aircraft and spacecraft applications that would benefit from 30 to 40% weight savings and substantial cost savings compared to aluminum lithium tanks.

Dimensional Metrology of Non-rigid Parts Without Specialized Inspection Fixtures =

NASA Astrophysics Data System (ADS)

Sabri, Vahid

Quality control is an important factor for manufacturing companies looking to prosper in an era of globalization, market pressures and technological advances. Functionality and product quality cannot be guaranteed without this important aspect. Manufactured parts have deviations from their nominal (CAD) shape caused by the manufacturing process. Thus, geometric inspection is a very important element in the quality control of mechanical parts. We will focus here on the geometric inspection of non-rigid (flexible) parts which are widely used in the aeronautic and automotive industries. Non-rigid parts can have different forms in a free-state condition compared with their nominal models due to residual stress and gravity loads. To solve this problem, dedicated inspection fixtures are generally used in industry to compensate for the displacement of such parts for simulating the use state in order to perform geometric inspections. These fixtures and the installation and inspection processes are expensive and time-consuming. Our aim in this thesis is therefore to develop an inspection method which eliminates the need for specialized fixtures. This is done by acquiring a point cloud from the part in a free-state condition using a contactless measuring device such as optical scanning and comparing it with the CAD model for the deviation identification. Using a non-rigid registration method and finite element analysis, we numerically inspect the profile of a non-rigid part. To do so, a simulated displacement is performed using an improved definition of displacement boundary conditions for simulating unfixed parts. In addition, we propose a numerical method for dimensional metrology of non-rigid parts in a free-state condition based on the arc length measurement by calculating the geodesic distance using the Fast Marching Method (FMM). In this thesis, we apply our developed methods on industrial non-rigid parts with free-form surfaces simulated with different types of displacement, defect, and measurement noise in order to evaluate the metrological performance of the developed methods.

Experimental modal substructuring to couple and uncouple substructures with flexible fixtures and multi-point connections

NASA Astrophysics Data System (ADS)

Allen, Matthew S.; Mayes, Randall L.; Bergman, Elizabeth J.

2010-11-01

Modal substructuring or component mode synthesis (CMS) has been standard practice for many decades in the analytical realm, yet a number of significant difficulties have been encountered when attempting to combine experimentally derived modal models with analytical ones or when predicting the effect of structural modifications using experimental measurements. This work presents a new method that removes the effects of a flexible fixture from an experimentally obtained modal model. It can be viewed as an extension to the approach where rigid masses are removed from a structure. The approach presented here improves the modal basis of the substructure, so that it can be used to more accurately estimate the modal parameters of the built-up system. New types of constraints are also presented, which constrain the modal degrees of freedom of the substructures, avoiding the need to estimate the connection point displacements and rotations. These constraints together with the use of a flexible fixture enable a new approach for joining structures, especially those with statically indeterminate multi-point connections, such as two circular flanges that are joined by many more bolts than required to enforce compatibility if the substructures were rigid. Fixture design is discussed, one objective of which is to achieve a mass-loaded boundary condition that exercises the substructure at the connection point as it is in the built up system. The proposed approach is demonstrated with two examples using experimental measurements from laboratory systems. The first is a simple problem of joining two beams of differing lengths, while the second consists of a three-dimensional structure comprising a circular plate that is bolted at eight locations to a flange on a cylindrical structure. In both cases frequency response functions predicted by the substructuring methods agree well with those of the actual coupled structures over a significant range of frequencies.

16 CFR 1510.4 - Test procedure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Test procedure. 1510.4 Section 1510.4... REQUIREMENTS FOR RATTLES § 1510.4 Test procedure. Place the test fixture shown in Figure 1 on a horizontal plane surface. Under its own weight and in a non-compressed state apply any portion of the test sample...

Plasma Chamber Design and Fabrication Activities

NASA Astrophysics Data System (ADS)

Parodi, B.; Bianchi, A.; Cucchiaro, A.; Coletti, A.; Frosi, P.; Mazzone, G.; Pizzuto, A.; Ramogida, G.; Coppi, B.

2006-10-01

A fabrication procedure for a typical Plasma Chamber (PC) sector has been developed to cover all the manufacturing phases, from the raw materials specification (including metallurgical processes) to the machining operations, acceptance procedures and vacuum tests. Basically, the sector is made of shaped elements (forged or rolled) welded together using special fixtures and then machined to achieve the final dimensional accuracy. An upgraded design of the plasma chamber's vertical support that can withstand the estimated electromagnetic loads (Eddy and Halo current plus horizontal net force resulting from the worst plasma disruption scenario VDE, Vertical Displacement Event) has been completed. The maintenance of the radial support can take place hands-on with a direct access from outside the cryostat. With the present design, vacuum tightness is achieved by welding conducted with automatic welding heads. On the outer surface of the PC a dedicated duct system, filled by helium gas, is included to cool down the PC to room temperature when needed.

Automated Transmission Loss Measurement in the Structural Acoustic Loads and Transmission Facility at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Klos, J.; Brown, S. A.

2002-01-01

A technique to measure the radiated acoustic intensity and transmission loss of panels is documented in this paper. This facility has been upgraded to include a test fixture that scans the acoustic intensity radiated from a panel on the anechoic receiving room side of the transmission loss window. The acoustic intensity incident on the panel from the reverberant side of the transmission loss window is estimated from measurements made using six stationary microphones in the reverberant source room. From the measured incident and radiated intensity, the sound power transmission loss is calculated. The setup of the facility and data acquisition system are documented. A transmission loss estimate of a typical panel is shown. The measurement-to-measurement and setup-to-setup repeatability of the transmission loss estimate are assessed. Conclusions are drawn about the ability to measure changes in transmission loss due to changes in panel construction.

Friction testing of a new ligature

NASA Astrophysics Data System (ADS)

Mantel, Alison R.

Objective. To determine if American Orthodontics' (AO) new, experimental ligature demonstrates less friction in vitro when compared to four other ligatures on the market. Methods. Four brackets were mounted on a custom metal fixture allowing an 0.018-in stainless steel wire attached to an opposite fixture with one bracket to be passively centered in the bracket slot. The wire was ligated to the bracket using one of five types of ligatures including the low friction test ligatures (AO), conventional ligatures (AO), Sili-Ties(TM) Silicone Infused Ties (GAC), SynergyRTM Low-Friction Ligatures (RMO), and SuperSlick ligatures (TP Orthodontics). Resistance to sliding was measured over a 7 mm sliding distance using a universal testing machine (Instron) with a 50 Newton load cell and a crosshead speed of 5 mm/min. The initial resistance to sliding (static) was determined by the peak force needed to initiate movement and the kinetic resistance to sliding was taken as the force at 5 mm of wire/bracket sliding. Fifteen unique tests were run for each ligature group in both dry and wet (saliva soaked for 24 hours with one drop prior to testing) conditions. Results. In the dry state, the SuperSlick ligature demonstrated more static friction than all of the other ligatures, while SuperSlick and Sili-Ties demonstrated more kinetic friction than the AO conventional, AO experimental and Synergy ligatures. In the wet condition, SuperSlick and the AO experimental ligature demonstrated the least static friction, followed by the AO conventional and Sili-Ties. The most static friction was observed with the Synergy ligatures. In the wet condition, the SuperSlick, AO experimental and AO conventional exhibited less kinetic friction than the Sili-Ties and Synergy ligatures. Conclusions. AO's experimental ligature exhibits less friction in the wet state than conventional ligatures, Sili-Ties and Synergy and is comparable to the SuperSlick ligature. These preliminary results suggest that the AO experimental ligature and the SuperSlick ligature create less friction, but direct conclusions regarding in vivo performance cannot be made and randomized controlled clinical trials are needed to determine if these ligatures have clinical significance in treatment efficiency.

Intrinsic Impact and Fatigue Property Degradation of Composite Materials in Sea Water

DTIC Science & Technology

2010-05-26

Erdogan and G. Sih. On the crack extension in plates under plane loading and transverse shear. Journal of Basic Engineering. 85, 1963. 519-527. L. B...using a thin tape . The adhesive was then applied to the other half and the specimen was bonded using a special fixture to guarantee dimensionality...a pure mode II crack is needed, rather than a kinked mode I crack. The angle of the crack kinking can be calculated theoretically ( Erdogan and Sih

Feasibility Study of a Precision Cast Loading Machine for Small Ammunition Items

DTIC Science & Technology

1975-05-01

distribution unlimited. READ INStRUCTIONS BEFORE COMPLETING FORM 1. RECIPIENT’S CATALOG NUMBER S. TYRE OF REPORT « PERIOD COVERED S. PCRFORMINO ORO...through a short length rubber hose into the hemisphere. A clamp actuated by an air cylinder can close or open the rubber hose. Because of unknown... rubber hose in the recess on the face of the fixture, exposing opposite hole for observation by the TV monitor through the TV camera. 8. Release table

Measurement of impulse peak insertion loss for four hearing protection devices in field conditions

PubMed Central

Murphy, William J.; Flamme, Gregory A.; Meinke, Deanna K.; Sondergaard, Jacob; Finan, Donald S.; Lankford, James E.; Khan, Amir; Vernon, Julia; Stewart, Michael

2015-01-01

Objective In 2009, the U.S. Environmental Protection Agency (EPA) proposed an impulse noise reduction rating (NRR) for hearing protection devices based upon the impulse peak insertion loss (IPIL) methods in the ANSI S12.42-2010 standard. This study tests the ANSI S12.42 methods with a range of hearing protection devices measured in field conditions. Design The method utilizes an acoustic test fixture and three ranges for impulse levels: 130–134, 148–152, and 166–170 dB peak SPL. For this study, four different models of hearing protectors were tested: Bilsom 707 Impact II electronic earmuff, E·A·R Pod Express, E·A·R Combat Arms version 4, and the Etymotic Research, Inc. Electronic BlastPLG™ EB1. Study sample Five samples of each protector were fitted on the fixture or inserted in the fixture's ear canal five times for each impulse level. Impulses were generated by a 0.223 caliber rifle. Results The average IPILs increased with peak pressure and ranged between 20 and 38 dB. For some protectors, significant differences were observed across protector examples of the same model, and across insertions. Conclusions The EPA's proposed methods provide consistent and reproducible results. The proposed impulse NRR rating should utilize the minimum and maximum protection percentiles as determined by the ANSI S12.42-2010 methods. PMID:22176308

Characterization of viscoelastic materials for low-magnitude blast mitigation

NASA Astrophysics Data System (ADS)

Bartyczak, S.; Mock, W.

2014-05-01

Recent research indicates that exposure to low amplitude blast waves, such as IED detonation or multiple firings of a weapon, causes damage to brain tissue resulting in Traumatic Brain Injury (TBI) and Post Traumatic Stress Disorder (PTSD). Current combat helmets are not sufficiently protecting warfighters from this danger and the effects are debilitating, costly, and long-lasting. The objective of the present work is to evaluate the blast mitigating behavior of current helmet materials and new materials designed for blast mitigation using a test fixture recently developed at the Naval Surface Warfare Center Dahlgren Division for use with an existing gas gun. The 40-mm-bore gas gun was used as a shock tube to generate blast waves (ranging from 0.5 to 2 bar) in the test fixture mounted on the gun muzzle. A fast opening valve was used to release helium gas from the breech which formed into a blast wave and impacted instrumented targets in the test fixture. Blast attenuation of selected materials was determined through the measurement of stress data in front of and behind the target. Materials evaluated in this research include polyurethane foam from currently fielded US Army and Marine Corps helmets, polyurea 1000, and three hardnesses of Sorbothane (48, 58, and 70 durometer, Shore 00). Polyurea 1000 and 6061-T6 aluminum were used to calibrate the stress gauges.

10 CFR 431.325 - Units to be tested.

Code of Federal Regulations, 2011 CFR

2011-01-01

... EQUIPMENT Metal Halide Lamp Ballasts and Fixtures Test Procedures § 431.325 Units to be tested. For each basic model of metal halide lamp ballast selected for testing, a sample of sufficient size, no less than... energy efficiency calculated as the measured output power to the lamp divided by the measured input power...

Apparatus for Hot Impact Testing of Material Specimens

NASA Technical Reports Server (NTRS)

Pawlik, Ralph J.; Choi, Sung R.

2006-01-01

An apparatus for positioning and holding material specimens is a major subsystem of a system for impact testing of the specimens at temperatures up to 1,500 C. This apparatus and the rest of the system are designed especially for hot impact testing of advanced ceramics, composites, and coating materials. The apparatus includes a retaining fixture on a rotating stage on a vertically movable cross support driven by a linear actuator. These components are located below a furnace wherein the hot impact tests are performed (see Figure 1). In preparation for a test, a specimen is mounted on the retaining fixture, then the cross support is moved upward to raise the specimen, through an opening in the bottom of the furnace, to the test position inside the furnace. On one side of the furnace there is another, relatively small opening on a direct line to the specimen. Once the specimen has become heated to the test temperature, the test is performed by using an instrumented external pressurized-gas-driven gun to shoot a projectile through the side opening at the specimen.

Variable Acceleration Force Calibration System (VACS)

NASA Technical Reports Server (NTRS)

Rhew, Ray D.; Parker, Peter A.; Johnson, Thomas H.; Landman, Drew

2014-01-01

Conventionally, force balances have been calibrated manually, using a complex system of free hanging precision weights, bell cranks, and/or other mechanical components. Conventional methods may provide sufficient accuracy in some instances, but are often quite complex and labor-intensive, requiring three to four man-weeks to complete each full calibration. To ensure accuracy, gravity-based loading is typically utilized. However, this often causes difficulty when applying loads in three simultaneous, orthogonal axes. A complex system of levers, cranks, and cables must be used, introducing increased sources of systematic error, and significantly increasing the time and labor intensity required to complete the calibration. One aspect of the VACS is a method wherein the mass utilized for calibration is held constant, and the acceleration is changed to thereby generate relatively large forces with relatively small test masses. Multiple forces can be applied to a force balance without changing the test mass, and dynamic forces can be applied by rotation or oscillating acceleration. If rotational motion is utilized, a mass is rigidly attached to a force balance, and the mass is exposed to a rotational field. A large force can be applied by utilizing a large rotational velocity. A centrifuge or rotating table can be used to create the rotational field, and fixtures can be utilized to position the force balance. The acceleration may also be linear. For example, a table that moves linearly and accelerates in a sinusoidal manner may also be utilized. The test mass does not have to move in a path that is parallel to the ground, and no re-leveling is therefore required. Balance deflection corrections may be applied passively by monitoring the orientation of the force balance with a three-axis accelerometer package. Deflections are measured during each test run, and adjustments with respect to the true applied load can be made during the post-processing stage. This paper will present the development and testing of the VASC concept.

Dynamic Test Method Based on Strong Electromagnetic Pulse for Electromagnetic Shielding Materials with Field-Induced Insulator-Conductor Phase Transition

NASA Astrophysics Data System (ADS)

Wang, Yun; Zhao, Min; Wang, Qingguo

2018-01-01

In order to measure the pulse shielding performance of materials with the characteristic of field-induced insulator-conductor phase transition when materials are used for electromagnetic shielding, a dynamic test method was proposed based on a coaxial fixture. Experiment system was built by square pulse source, coaxial cable, coaxial fixture, attenuator, and oscilloscope and insulating components. S11 parameter of the test system was obtained, which suggested that the working frequency ranges from 300 KHz to 7.36 GHz. Insulating performance is good enough to avoid discharge between conductors when material samples is exposed in the strong electromagnetic pulse field up to 831 kV/m. This method is suitable for materials with annular shape, certain thickness and the characteristic of field-induced insulator-conductor phase transition to get their shielding performances of strong electromagnetic pulse.

Cryogenic Flange and Seal Evaluation

NASA Technical Reports Server (NTRS)

Ramirez, Adrian

2014-01-01

The assembly of flanges, seals, and pipes are used to carry cryogenic fluid from a storage tank to the vehicle at launch sites. However, after a certain amount of cycles these raised face flanges with glass-filled Teflon gaskets have been found to have torque relaxation and are as a result susceptible to cryogenic fluid leakage if not re-torqued. The intent of this project is to identify alternate combinations of flanges and seals which may improve thermal cycle performance and decrease re-torque requirements. The general approach is to design a test fixture to evaluate leak characteristics between spiral and concentric serrations and to test alternate flange and seal combinations. Due to insufficient time, it was not possible to evaluate these different types of combinations for the combination that improved thermal cycle performance the most. However, the necessary drawings for the test fixture were designed and assembled along with the collection of the necessary parts.

A Cryogenic Waveguide Mount for Microstrip Circuit and Material Characterization

NASA Technical Reports Server (NTRS)

U-yen, Kongpop; Brown, Ari D.; Moseley, Samuel H.; Noroozian, Omid; Wollack, Edward J.

2016-01-01

A waveguide split-block fixture used in the characterization of thin-film superconducting planar circuitry at millimeter wavelengths is described in detail. The test fixture is realized from a pair of mode converters, which transition from rectangular-waveguide to on-chip microstrip-line signal propagation via a stepped ridge-guide impedance transformer. The observed performance of the W-band package at 4.2K has a maximum in-band transmission ripple of 2dB between 1.53 and 1.89 times the waveguide cutoff frequency. This metrology approach enables the characterization of superconducting microstrip test structures as a function temperature and frequency. The limitations of the method are discussed and representative data for superconducting Nb and NbTiN thin film microstrip resonators on single-crystal Si dielectric substrates are presented.

Fracture behavior of large-scale thin-sheet aluminum alloy

NASA Technical Reports Server (NTRS)

Dewit, Roland; Fields, Richard J.; Mordfin, Leonard; Low, Samuel R.; Harne, Donald

1994-01-01

A series of fracture tests on large-scale, pre-cracked, aluminum alloy panels is being carried out to examine and to characterize the process by which cracks propagate and link up in this material. Extended grips and test fixtures were specially designed to enable the panel specimens to be loaded in tension, in a 1780-kN-capacity universal testing machine. Twelve panel specimens, each consisting of a single sheet of bare 2024-T3 aluminum alloy, 3988 mm high, 2286 mm wide, and 1.016 mm thick are being fabricated with simulated through-cracks oriented horizontally at mid-height. Using existing information, a test matrix has been set up that explores regions of failure that are controlled by fracture mechanics, with additional tests near the boundary between plastic collapse and fracture. In addition, a variety of multiple site damage (MSD) configurations have been included to distinguish between various proposed linkage mechanisms. All tests but one use anti-buckling guides. At this writing seven specimens have been tested. Three were fabricated with a single central crack, three others had multiple cracks on each side of the central crack, and one had a single crack but no anti-buckling guides. Each fracture event was recorded on film, video, computer, magnetic tape, and occasionally optical microscopy. The visual showed the crack tip with a load meter in the field of view, using motion picture film for one tip and SVHS video tape for the other. The computer recorded the output of the testing machine load cell, the stroke, and twelve strain gages at 1.5 second intervals. A wideband FM magnetic tape recorder was used to record data from the same sources. The data were analyzed by two different procedures: (1) the plastic zone model based on the residual strength diagram; and (2) the R-curve. The first three tests were used to determine the basic material properties, and these results were then used in the analysis of the two subsequent tests with MSD cracks. There is good agreement between measured values and results obtained from the model.

Handheld Micromanipulation with Vision-Based Virtual Fixtures

PubMed Central

Becker, Brian C.; MacLachlan, Robert A.; Hager, Gregory D.; Riviere, Cameron N.

2011-01-01

Precise movement during micromanipulation becomes difficult in submillimeter workspaces, largely due to the destabilizing influence of tremor. Robotic aid combined with filtering techniques that suppress tremor frequency bands increases performance; however, if knowledge of the operator's goals is available, virtual fixtures have been shown to greatly improve micromanipulator precision. In this paper, we derive a control law for position-based virtual fixtures within the framework of an active handheld micromanipulator, where the fixtures are generated in real-time from microscope video. Additionally, we develop motion scaling behavior centered on virtual fixtures as a simple and direct extension to our formulation. We demonstrate that hard and soft (motion-scaled) virtual fixtures outperform state-of-the-art tremor cancellation performance on a set of artificial but medically relevant tasks: holding, move-and-hold, curve tracing, and volume restriction. PMID:23275860

Evaluation of Testing Methods to Develop Test Requirements for a Workstation Table Safety Standard

DOT National Transportation Integrated Search

2010-10-12

Investigations of passenger train accidents have revealed serious safety hazards associated with the thin, rigid tops of workstation tables, which are common fixtures aboard rail cars. Thoracic and abdominal injuries caused by occupant impact with wo...

Draw forming of scale shuttle external tank dome gores

NASA Technical Reports Server (NTRS)

Garfield, G.

1974-01-01

The process for manufacturing external tank dome gores is discussed. The test fixture and test procedure are described. The characteristics of the draw forming die are analyzed. The specific subjects included are: (1) forming, (2) trimming, (3) cleaning, and (4) heat treatment.

Temporary implant-supported prosthesis for immediate loading according to a chair-side concept: technical note and results from 37 consecutive cases.

PubMed

Ostman, Pär-Olov; Hellman, Mats; Sennerby, Lars; Wennerberg, Ann

2008-05-01

During the last years, focus has been paid to implant treatment using immediate function protocols, and different approaches to provide patients with temporary constructions have been presented. Most of these techniques involve dental technicians producing the temporary construction, for example, rebuilding existing dentures, acrylic bridges, etc. The purpose of this prospective clinical study was to evaluate the clinical outcome of a chair-side technique of a cost-effective temporary prosthesis. Fixture survival rate and risk of temporary bridge failure were analyzed. Thirty-seven partially or totally edentate patients (18 female and 19 male; mean age: 66.7 years) treated with chair-side manufactured temporary restorations (QuickBridge, BIOMET 3i, Palm Beach, Fl, USA) for immediate loading have been evaluated. The prostheses extended from two unit bridges supported by two implants to full-arch construction supported by six implants. The temporary prostheses were monitored from the day of surgery and delivery to the time of replacement with a permanent prosthetic construction 3 to 6 months later. No implants were lost during the observation time. One (3%) temporary prosthesis fractured and additional two (6%) loosened during the follow-up time. The study indicated that the tested chair-side concept for manufacturing of temporary prosthesis for immediate loading of dental implants is a viable approach.

In-service testing of Ni{sub 3}Al coupons and trays in carburizing furnaces at Delphi Saginaw. CRADA final report

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

Sikka, V.K.; Santella, M.L.; Viswanathan, S.

1998-08-01

This Cooperative Research and Development Agreement (CRADA) report deals with the development of nickel aluminide alloy for improved longer life heat-resistant fixture assemblies for batch and continuous pusher carburizing furnaces. The nickel aluminide development was compared in both coupon and component testing with the currently used Fe-Ni-Cr heat-resisting alloy known as HU. The specific goals of the CRADA were: (1) casting process development, (2) characterization and possible modification of the alloy composition to optimize its manufacturing ability and performance under typical furnace operating conditions, and (3) testing and evaluation of specimens and prototype fixtures. In support of the CRADA objectives,more » coupons of nickel aluminide and the HU alloy were installed in both batch and pusher furnaces. The coupons were taken from two silicon levels and contained welds made with two different filler compositions (IC-221LA and IC-221W). Both nickel-aluminide and HU coupons were removed from the batch and pusher carburizing furnace at time intervals ranging from one month to one year. The exposed coupons were cut and mounted for metallographic, hardness, and microprobe analysis. The results of the microstructural analysis have been transmitted to General Motors Corporation, Saginaw Division (Delphi Saginaw) through reports that were presented at periodic CRADA review meetings. Based on coupon testing and verification of the coupon results with the testing of trays, Delphi Saginaw moved forward with the use of six additional trays in a batch furnace and two assemblies in a pusher furnace. Fifty percent of the trays and fixtures are in the as-cast condition and the remaining trays and fixtures are in the preoxidized condition. The successful operating experience of two assemblies in the pusher furnace for nearly a year formed the basis for a production run of 63 more assemblies. The production run required melting of 94 heats weighing 500 lb. each. Twenty-six of the 94 heats were from virgin stock, and 68 were from the revert that used 50% virgin and 50% revert. Detailed chemical analysis of the 94 heats reflected that the nickel aluminide can be cast into heat-treat fixtures under production conditions. In addition to the chemical analysis, the castings showed excellent dimensional reproducibility. A total of six batch furnace trays and 65 pusher furnace assemblies of nickel aluminide alloy IC-221M are currently operating in production furnaces at Delphi Saginaw. Two of the pusher furnace assemblies have completed two years of service without any failure. The CRADA has accomplished the goal of demonstrating that the nickel aluminide can be produced under commercial production conditions and it has superior performance over the currently used HU alloy in both batch and pusher furnaces.« less

Vision-Based Control of a Handheld Surgical Micromanipulator with Virtual Fixtures

PubMed Central

Becker, Brian C.; MacLachlan, Robert A.; Lobes, Louis A.; Hager, Gregory D.; Riviere, Cameron N.

2012-01-01

Performing micromanipulation and delicate operations in submillimeter workspaces is difficult because of destabilizing tremor and imprecise targeting. Accurate micromanipulation is especially important for microsurgical procedures, such as vitreoretinal surgery, to maximize successful outcomes and minimize collateral damage. Robotic aid combined with filtering techniques that suppress tremor frequency bands increases performance; however, if knowledge of the operator’s goals is available, virtual fixtures have been shown to further improve performance. In this paper, we derive a virtual fixture framework for active handheld micromanipulators that is based on high-bandwidth position measurements rather than forces applied to a robot handle. For applicability in surgical environments, the fixtures are generated in real-time from microscope video during the procedure. Additionally, we develop motion scaling behavior around virtual fixtures as a simple and direct extension to the proposed framework. We demonstrate that virtual fixtures significantly outperform tremor cancellation algorithms on a set of synthetic tracing tasks (p < 0.05). In more medically relevant experiments of vein tracing and membrane peeling in eye phantoms, virtual fixtures can significantly reduce both positioning error and forces applied to tissue (p < 0.05). PMID:24639624

Virtual fixtures as tools to enhance operator performance in telepresence environments

NASA Astrophysics Data System (ADS)

Rosenberg, Louis B.

1993-12-01

This paper introduces the notion of virtual fixtures for use in telepresence systems and presents an empirical study which demonstrates that such virtual fixtures can greatly enhance operator performance within remote environments. Just as tools and fixtures in the real world can enhance human performance by guiding manual operations, providing localizing references, and reducing the mental processing required to perform a task, virtual fixtures are computer generated percepts overlaid on top of the reflection of a remote workspace which can provide similar benefits. Like a ruler guiding a pencil in a real manipulation task, a virtual fixture overlaid on top of a remote workspace can act to reduce the mental processing required to perform a task, limit the workload of certain sensory modalities, and most of all allow precision and performance to exceed natural human abilities. Because such perceptual overlays are virtual constructions they can be diverse in modality, abstract in form, and custom tailored to individual task or user needs. This study investigates the potential of virtual fixtures by implementing simple combinations of haptic and auditory sensations as perceptual overlays during a standardized telemanipulation task.

Marginal bone levels at single tooth implants with a conical fixture design. The influence of surface macro- and microstructure.

PubMed

Norton, M R

1998-04-01

The concept of a conical implant design to accommodate single tooth replacement, has previously been shown to result in excessive bone loss, around the machined titanium conical collar, usually down to the 1st thread. This unusually aggressive loss of bone was shown to occur within a short period of time, post loading, with greater than 3 mm of bone loss occurring within the 1st 6 months to 1 year. The influence of implant design, surface texture and microleakage have all been highlighted as a potential cause. A modification of the surface structure, both at the macroscopic and microscopic level, as well as an altered fixture-abutment interface design has resulted in the maintenance of marginal bone around a single tooth titanium implant with a similar conical design. The radiographic follow-up of 33 implants loaded for up to 4 years, has revealed, by comparison, a most favourable maintenance of marginal bone around the conical collar, with a mean marginal bone loss of 0.32 mm mesially and 0.34 mm distally for the whole group. The cumulative mean marginal bone loss mesially and distally is 0.42 mm and 0.40 mm from 1 to 2 years, 0.54 mm and 0.43 mm from 2 to 3 years, 0.51 mm and 0.24 mm from 3 to 4 years, and 0.62 mm and 0.60 mm for implants past their 4 year recall.

TX-100 manufacturing final project report.

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

Ashwill, Thomas D.; Berry, Derek S.

This report details the work completed under the TX-100 blade manufacturing portion of the Carbon-Hybrid Blade Developments: Standard and Twist-Coupled Prototype project. The TX-100 blade is a 9 meter prototype blade designed with bend-twist coupling to augment the mitigation of peak loads during normal turbine operation. This structural coupling was achieved by locating off axis carbon fiber in the outboard portion of the blade skins. The report will present the tooling selection, blade production, blade instrumentation, blade shipping and adapter plate design and fabrication. The baseline blade used for this project was the ERS-100 (Revision D) wind turbine blade. Themore » molds used for the production of the TX-100 were originally built for the production of the CX-100 blade. The same high pressure and low pressure skin molds were used to manufacture the TX-100 skins. In order to compensate for the difference in skin thickness between the CX-100 and the TX-100, however, a new TX-100 shear web plug and mold were required. Both the blade assembly fixture and the root stud insertion fixture used for the CX-100 blades could be utilized for the TX-100 blades. A production run of seven TX-100 prototype blades was undertaken at TPI Composites during the month of October, 2004. Of those seven blades, four were instrumented with strain gauges before final assembly. After production at the TPI Composites facility in Rhode Island, the blades were shipped to various test sites: two blades to the National Wind Technology Center at the National Renewable Energy Laboratory in Boulder, Colorado, two blades to Sandia National Laboratory in Albuquerque, New Mexico and three blades to the United States Department of Agriculture turbine field test facility in Bushland, Texas. An adapter plate was designed to allow the TX-100 blades to be installed on existing Micon 65/13M turbines at the USDA site. The conclusion of this program is the kick-off of the TX-100 blade testing at the three testing facilities.« less

18. FIRST FLOOR, DETAIL OF CEILING AND LIGHT FIXTURE (AS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. FIRST FLOOR, DETAIL OF CEILING AND LIGHT FIXTURE (AS SEEN IN SC-135-18), MADE OF BRASS, ORIGINALLY GAS, CONVERTED TO ELECTRICITY, FIXTURE LIT - Market Hall, 188 Meeting Street, Charleston, Charleston County, SC

Dissipation factor as a predictor of anodic coating performance

DOEpatents

Panitz, Janda K. G.

1995-01-01

A dissipation factor measurement is used to predict as-anodized fixture performance prior to actual use of the fixture in an etching environment. A dissipation factor measurement of the anodic coating determines its dielectric characteristics and correlates to the performance of the anodic coating in actual use. The ability to predict the performance of the fixture and its anodized coating permits the fixture to be repaired or replaced prior to complete failure.

Development of an improved GTA (gas tungsten arc) weld temperature monitor fixture

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

Hollar, D.L.

1990-05-01

An initial design weld temperature control fixture was implemented into final closure of an electronic assembly in November 1986. Use of this fixture indicated several areas that could be improved. Review of these areas with the process engineer and the weld operator provided the ideas to be incorporated into the new design Phase 2 fixture. Some primary areas of change and improvement included fixture mobility to provide better accessibility to the weld joint area, automatic timed blow cooling of the weld joint, and a feature to assure proper thermocouple placement. The resulting Phase 2 fixture design provided all of themore » essential weld temperature monitoring features in addition to several significant improvements. Technology developed during this project will pave the way to similar process monitoring of other manual gas tungsten arc (GTA) welding applications. 9 figs.« less

Investigation of thermal management technique in blue LED airport taxiway fixtures

NASA Astrophysics Data System (ADS)

Gu, Yimin; Baker, Alex; Narendran, Nadarajah

2007-09-01

On airport runways, blue light fixtures denote taxiways between the runway and the airport terminal. Blue optics transmit mostly short-wavelength radiation, which makes traditional incandescent lamps a poor choice of light source; the resulting fixture efficiency could be less than one percent. LEDs are replacing incandescent lamps in this application. But unlike incandescent sources, LEDs do not radiate enough heat to melt ice and snow from the fixture optics. To meet Federal Aviation Administration (FAA) regulations for weatherability, some LED-based fixtures incorporate electric heaters that, when switched on, nearly negate the energy-savings benefit of converting to LED sources. In this study, we explored methods for conduction and convection of LED junction heat to taxiway fixture optics for the purpose of minimizing snow and ice buildup. A more efficient LED-based system compared to incandescent that would require no additional heaters was demonstrated.

1000542

NASA Image and Video Library

2010-04-13

HORACE STORNG (AEROSPACE ENGINEER, ER31 PROPULSION TURBOMACHINERY DESIGN & DEVELOPMENT BRANCH) ADJUSTS A UNIQUE MECHANICAL TEST SETUP THAT MEASURES STRAIN ON A SINGLE SAMPLE, USING TWO DIFFERENT TECHNIQUES AT THE SAME TIME. THE TEST FIXTURE HOLDS A SPECIMEN THAT REPRESENTS A LIQUID OXYGEN (LOX) BEARING FROM THE J2-X ENGINE

Evaluating of NASA-Langley Research Center explosion seam welding

NASA Technical Reports Server (NTRS)

Otto, H. E.; Wittman, R.

1977-01-01

An explosion bonding technique to meet current fabrication requirements was demonstrated. A test program was conducted on explosion bonded joints, compared to fusion joints in 6061-T6 aluminum. The comparison was made in required fixtures, non-destructive testing, static strength and fatigue strength.

A magnetic bearing control approach using flux feedback

NASA Technical Reports Server (NTRS)

Groom, Nelson J.

1989-01-01

A magnetic bearing control approach using flux feedback is described and test results for a laboratory model magnetic bearing actuator are presented. Test results were obtained using a magnetic bearing test fixture, which is also described. The magnetic bearing actuator consists of elements similar to those used in a laboratory test model Annular Momentum Control Device (AMCD).

24 CFR 3280.612 - Tests and inspection.

Code of Federal Regulations, 2012 CFR

2012-04-01

... to a pressure test. The test shall be made by subjecting the system to air or water at 100 psi for 15 minutes without loss of pressure. (b) Drainage and vent system and plumbing fixtures. The waste and vent... plugged, the entire system shall be subjected to a 2-inch (manometer) water column air pressure test. If...

24 CFR 3280.612 - Tests and inspection.

Code of Federal Regulations, 2014 CFR

2014-04-01

... to a pressure test. The test shall be made by subjecting the system to air or water at 100 psi for 15 minutes without loss of pressure. (b) Drainage and vent system and plumbing fixtures. The waste and vent... plugged, the entire system shall be subjected to a 2-inch (manometer) water column air pressure test. If...

24 CFR 3280.612 - Tests and inspection.

Code of Federal Regulations, 2013 CFR

2013-04-01

... to a pressure test. The test shall be made by subjecting the system to air or water at 100 psi for 15 minutes without loss of pressure. (b) Drainage and vent system and plumbing fixtures. The waste and vent... plugged, the entire system shall be subjected to a 2-inch (manometer) water column air pressure test. If...

24 CFR 3280.612 - Tests and inspection.

Code of Federal Regulations, 2011 CFR

2011-04-01

... to a pressure test. The test shall be made by subjecting the system to air or water at 100 psi for 15 minutes without loss of pressure. (b) Drainage and vent system and plumbing fixtures. The waste and vent... plugged, the entire system shall be subjected to a 2-inch (manometer) water column air pressure test. If...

4th Day of Equipment Being Loaded for Recovery of Orion

NASA Image and Video Library

2014-11-20

The Orion handling fixture, special bumpers and other ground support equipment are secured in the well deck of the USS Anchorage at Naval Base San Diego in California. The equipment will be used during recovery of the Orion crew module after its first flight test. Before launch of Orion on a Delta IV Heavy rocket from Cape Canaveral Air Force Station in Florida, NASA, Lockheed Martin and U.S. Navy personnel will head out to sea in the USS Anchorage and the USNS Salvor, a salvage ship, and wait for splashdown of the Orion crew module in the Pacific Ocean. The Ground Systems Development and Operations Program will lead the recovery efforts. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted flight test of Orion is scheduled to launch in December atop a United Launch Alliance Delta IV Heavy rocket and in 2018 on NASA’s Space Launch System rocket.

4th Day of Equipment Being Loaded for Recovery of Orion

NASA Image and Video Library

2014-11-20

The Orion handling fixture and other ground support equipment is secured in the well deck of the USS Anchorage at Naval Base San Diego in California. The equipment will be used during recovery of the Orion crew module after its first flight test. Before launch of Orion on a Delta IV Heavy rocket from Cape Canaveral Air Force Station in Florida, NASA, Lockheed Martin and U.S. Navy personnel will head out to sea in the USS Anchorage and the USNS Salvor, a salvage ship, and wait for splashdown of the Orion crew module in the Pacific Ocean. The Ground Systems Development and Operations Program will lead the recovery efforts. Orion is the exploration spacecraft designed to carry astronauts to destinations not yet explored by humans, including an asteroid and Mars. It will have emergency abort capability, sustain the crew during space travel and provide safe re-entry from deep space return velocities. The first unpiloted flight test of Orion is scheduled to launch in December atop a United Launch Alliance Delta IV Heavy rocket and in 2018 on NASA’s Space Launch System rocket.

Development of a Contact Permeation Test Fixture and Method

DTIC Science & Technology

2013-04-01

direct contact with the skin, indicates the need for a quantitative contact test method. Comparison tests were conducted with VX on a standardized...Guide for the Care and Use of Laboratory Animals (8th ed.; National Research Council: Washington, DC, 2011). This test was also performed in...1 1.2 Development of a Contact-Based Permeation Test Method ........................................ 1 2. EXPERIMENTAL PROCEDURES

The test facility requirements for the thermal vacuum thermal balance test of the Cosmic Background Explorer Observatory

NASA Technical Reports Server (NTRS)

Milam, Laura J.

1990-01-01

The Cosmic Background Explorer Observatory (COBE) underwent a thermal vacuum thermal balance test in the Space Environment Simulator (SES). This was the largest and most complex test ever conducted at this facility. The 4 x 4 m (13 x 13 ft) spacecraft weighed approx. 2223 kg (4900 lbs) for the test. The test set up included simulator panels for the inboard solar array panels, simulator panels for the flight cowlings, Sun and Earth Sensor stimuli, Thermal Radio Frequency Shield heater stimuli and a cryopanel for thermal control in the Attitude Control System Shunt Dissipator area. The fixturing also included a unique 4.3 m (14 ft) diameter Gaseous Helium Cryopanel which provided a 20 K environment for the calibration of one of the spacecraft's instruments, the Differential Microwave Radiometer. This cryogenic panel caused extra contamination concerns and a special method was developed and written into the test procedure to prevent the high buildup of condensibles on the panel which could have led to backstreaming of the thermal vacuum chamber. The test was completed with a high quality simulated space environment provided to the spacecraft. The test requirements, test set up, and special fixturing are described.

Recent advances with quiescent power supply current (I(sub DDQ)) testing at Sandia using the HP82000

NASA Astrophysics Data System (ADS)

Righter, A. W.; Leong, D. J.; Cox, L. B.

Last year at the HP82000 Users Group Meeting, Sandia National Laboratories gave a presentation on I(sub DDQ) testing. This year, some advances are presented on this testing including DUT board fixturing, external DC PMU measurement, and automatic IDD-All circuit calibration. Implementation is examined more than theory, with results presented from Sandia tests. After a brief summary I(sub DDQ) theory and testing concepts, how the break (hold state) vector and data formatting present a test vector generation concern for the HP82000 is described. Fixturing of the DUT board for both types of I(sub DDQ) measurement is then discussed, along with how the continuity test and test vector generation must be taken into account. Results of a test including continuity, IDD-All and I(sub DDQ) Value measurements is shown. Next, measurement of low current using an external PMU is discussed, including noise considerations, implementation and some test results showing nA-range measurements. A method is presented for automatic calibration of the IDD-All analog comparator circuit using RM BASIC on the HP82000, with implementation and measurement results. Finally, future directions for research in this area is explored.

Test facility requirements for the thermal vacuum thermal balance test of the Cosmic Background Explorer Observatory

NASA Technical Reports Server (NTRS)

Milam, Laura J.

1991-01-01

The Cosmic Background Explorer Observatory (COBE) underwant a thermal vacuum thermal balance test in the Space Environment Simulator (SES). This was the largest and most complex test ever conducted at this facility. The 4 x 4 m (13 x 13 ft) spacecraft weighed approx. 2223 kg (4900 lbs) for the test. The test set up included simulator panels for the inboard solar array panels, simulator panels for the flight cowlings, Sun and Earth Sensor stimuli, Thermal Radio Frequency Shield heater stimuli and a cryopanel for thermal control in the Attitude Control System Shunt Dissipator area. The fixturing also included a unique 4.3 m (14 ft) diameter Gaseous Helium Cryopanel which provided a 20 K environment for the calibration of one of the spacecraft's instruments, the Differential Microwave Radiometer. This cryogenic panel caused extra contamination concerns and a special method was developed and written into the test procedure to prevent the high buildup of condensibles on the panel which could have led to backstreaming of the thermal vacuum chamber. The test was completed with a high quality simulated space environment provided to the spacecraft. The test requirements, test set up, and special fixturing are described.

Solid-State Lighting Module (SSLM)

NASA Technical Reports Server (NTRS)

2008-01-01

The project's goal was to build a light-emitting-diode (LED)-based light fixture that is identical in fit, form, and function to the existing International Space Station (ISS) General Luminaire Assembly (GLA) light fixture and fly it on the ISS in early FY 2008 as a Station Detailed Test Objective (SDTO). Our design offers the following strengths: proven component hardware: Our design uses components flown in other KSC-developed hardware; heat path thermal pad: LED array heat is transferred from the circuit board by silicon pad, negating the need for a cooling fan; variable colorimetry: The output light color can be changed by inserting different LED combinations.

Aluminum Manganese Molten Salt Plating

DTIC Science & Technology

2006-06-01

fixture from overhead crane hook and locate fixture over the closed acid tank. 2. Ventilation a. Set valve positions as follows (same as Section I.4.a...overhead crane hook and position the fixture over the closed acid tank. (Will need to remove the top stainless steel rod, clasp the remaining rod with the... crane hook , replace the rod that was removed by threading it through the crane hook , and finally lift the fixture off its storage hook . The cotter

Self-aligning fixture used in lathe chuck jaw refacing

NASA Technical Reports Server (NTRS)

Linn, C. C.

1965-01-01

Self-aligning tool positions and rigidly holds lathe chuck jaws for refacing and truing of the clamping surface. The jaws clamp the fixture in the manner of clamping a workpiece. The fixture can be modified to accommodate four-jawed checks.

1000538

NASA Image and Video Library

2010-04-13

AYMAN GIRGIS (EM10 MATERIALS TEST ENGINEER, JACOBS ESTS GROUP/JTI) ADJUSTS DUAL LENSES FOR A UNIQUE MECHANICAL TST SETUP THAT MEASURES STRAIN ON A SINGLE SAMPLE, USING TWO DIFFERENT TECHNIQUES AT THE SAME TIME. THE TEST FIXTURE HOLDS A SPECIMEN THAT REPRESENTS A LIQUID OXYGEN (LOX) BEARING FROM THE J2-X ENGINE

1000540

NASA Image and Video Library

2010-04-13

ERIC EARHART (AEROSPACE ENGINEER, ER41 PROPULSION STRUCTURAL & DYNAMICS ANALYSIS BRANCH) DISCUSSES DATA PRODUCED BY A UNIQUE MECHANICAL TEST SETUP THAT MEASURES STRAIN ON A SINGLE SAMPLE, USING TWO DIFFERENT TECHNIQUES AT THE SAME TIME. THE TEST FIXTURE HOLDS A SPECIMEN THAT REPRESENTS A LIQUID OXYGEN (LOX) BEARING FROM THE J2-X ENGINE

Development of damage suppression system using embedded SMA foil sensor and actuator

NASA Astrophysics Data System (ADS)

Ogisu, Toshimichi; Nomura, Masato; Ando, Norio; Takaki, Junji; Song, Dong Y.; Takeda, Nobuo

2000-06-01

The recent studies suggest possible applications of shape memory alloy (SMA) for a smart health monitoring and suppression of damage growth. The authors have been conducting research and development studies on applications of embedded SMA foil sensors and actuators in CFRP laminates. The goal of this research is suppression of damage growth in CFRP laminates. At first, the authors proposed a concept of damage suppression in CFRP laminates. Then, the development studies are conducted in three phases. The first phase is the improvement of interlaminar shear strength between SMA and CFRP laminates. Some surface treatments were investigated for the improvement of bonding property by peel resistance test and single lap shear strength test. The second phase is the investigation of fabrication technique for producing a CFRP panel with embedded SMA foils. Fixture jigs were devised to introduce tensile loads during the fabrication process. The third phase is the strength demonstration of CFRP laminates with embedded SMA foils. Some strength test were conducted to obtain the design data for aircraft structures. It is confirmed that the shrinking force of pre-strained SMA influences to the strength and the crack density of CFRP panel.

Long-term evaluation of solid oxide fuel cell candidate materials in a 3-cell generic stack test fixture, part III: Stability and microstructure of Ce-(Mn,Co)-spinel coating, AISI441 interconnect, alumina coating, cathode and anode

NASA Astrophysics Data System (ADS)

Chou, Yeong-Shyung; Stevenson, Jeffry W.; Choi, Jung-Pyung

2014-07-01

A generic solid oxide fuel cell stack test fixture was developed to evaluate candidate materials and processing under realistic conditions. Part III of the work investigated the stability of Ce-(Mn,Co) spinel coating, AISI441 metallic interconnect, alumina coating, and cell's degradation. After 6000 h test, the spinel coating showed densification with some diffusion of Cr. At the metal interface, segregation of Si and Ti was observed, however, no continuous layer formed. The alumina coating for perimeter sealing areas appeared more dense and thick at the air side than the fuel side. Both the spinel and alumina coatings remained bonded. EDS analysis of Cr within the metal showed small decrease in concentration near the coating interface and would expect to cause no issue of Cr depletion. Inter-diffusion of Ni, Fe, and Cr between spot-welded Ni wire and AISI441 interconnect was observed and Cr-oxide scale formed along the circumference of the weld. The microstructure of the anode and cathode was discussed relating to degradation of the top and middle cells. Overall, the Ce-(Mn,Co) spinel coating, alumina coating, and AISI441 steel showed the desired long-term stability and the developed generic stack fixture proved to be a useful tool to validate candidate materials for SOFC.

Prospective randomized clinical trial of hydrophilic tapered implant placement at maxillary posterior area: 6 weeks and 12 weeks loading

PubMed Central

2016-01-01

PURPOSE Early loading of implant can be determined by excellent primary stability and characteristic of implant surface. The implant system with recently improved surface can have load application 4-6 weeks after installing in maxilla and mandible. This study evaluated the effect of healing period to the stability of hydrophilic tapered-type implant at maxillary posterior area. MATERIALS AND METHODS This study included 30 patients treated by hydrophilic tapered-type implants (total 41 implants at maxilla) and classified by two groups depending on healing period. Group 1 (11 patients, 15 implants) was a control group and the healing period was 12 weeks, and Group 2 (19 patients, 26 implants) was test group and the healing period was 6 weeks. Immediately after implant placement, at the first impression taking, implant stability was measured using Osstell Mentor. The patients also took periapical radiographs after restoration delivery, 12 months after restoration and final followup period. The marginal bone loss around the implants was measured using the periapical radiographs. RESULTS All implants were survived and success rate was 97.56%. The marginal bone loss was less than 1mm after 1 year postoperatively except the one implant. The stabilities of the implants were not correlated with age, healing period until loading, insertion torque (IT), the diameter of fixture and the location of implant. Only the quality of bone in group 2 (6 week) was correlated with the stability of implant. CONCLUSION Healing period of 6 weeks can make the similar clinical prognosis of implants to that of healing period of 12 weeks if bone quality is carefully considered in case of early loading. PMID:27826390

Advanced manufacturing development of a composite empennage component for L-1011 aircraft. Phase 4: Full scale ground test

NASA Technical Reports Server (NTRS)

Jackson, A. C.; Dorwald, F.

1982-01-01

The ground tests conducted on the advanced composite vertical fin (ACVF) program are described. The design and fabrication of the test fixture and the transition structure, static test of Ground Test Article (GTA) No. 1, rework of GTA No. 2, and static, damage tolerance, fail-safe and residual strength tests of GTA No. 2 are described.

Multisurface fixture permits easy grinding of tool bit angles

NASA Technical Reports Server (NTRS)

Jones, C. R.

1966-01-01

Multisurface fixture with a tool holder permits accurate grinding and finishing of right and left hand single point threading tools. All angles are ground by changing the fixture position to rest at various references angles without removing the tool from the holder.

Fixture For Drilling And Tapping A Curved Workpiece

NASA Technical Reports Server (NTRS)

Espinosa, P. S.; Lockyer, R. T.

1992-01-01

Simple fixture guides drilling and tapping of holes in prescribed locations and orientations on workpiece having curved surface. Tool conceived for use in reworking complexly curved helicopter blades made of composite materials. Fixture is block of rigid foam with epoxy filler, custom-fitted to surface contour, containing bushings and sleeves at drilling and tapping sites. Bushings changed, so taps and drills of various sizes accommodated. In use, fixture secured to surface by hold-down bolts extending through sleeves and into threads in substrate.

Profile of the wood furniture and fixtures industry. EPA Office of Compliance sector notebook project

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

NONE

1995-09-01

The furniture and fixtures industry encompasses companies that manufacture household, office, store, public building, and restaurant furniture and fixtures. The second section provides background information on the size, geographic distribution, employment, production, sales, and economic condition of the Wood Furniture and Fixtures industry. The type of facilities described within the document are also described in terms of their Standard Industrial Classification (SIC) codes. Additionally, this section contains a list of the largest companies in terms of sales.

Space assembly fixtures and aids

NASA Technical Reports Server (NTRS)

Bloom, K. A.; Lillenas, A. N.

1980-01-01

Concepts and requirements for assembly fixtures and aids necessary for the assembly and maintenance of spare platforms were studied. Emphasis was placed on erectable and deployable type structures with the shuttle orbiter as the assembly base. Both single and multiple orbiter flight cases for the platform assembly were considered. Applicable space platform assembly studies were reviewed to provide a data base for establishing the assembly fixture and aids design requirements, assembly constraints, and the development of representative design concepts. Conclusions indicated that fixture requirements will vary with platform size. Larger platforms will require translation relative to the orbiter RMS working volume. The installation of platform payloads and subsystems (e.g., utility distribution) must also be considered in the specification of assembly fixtures and aids.

Fixture for aligning motor assembly

DOEpatents

Shervington, Roger M.; Vaghani, Vallabh V.; Vanek, Laurence D.; Christensen, Scott A.

2009-12-08

An alignment fixture includes a rotor fixture, a stator fixture and a sensor system which measures a rotational displacement therebetween. The fixture precisely measures rotation of a generator stator assembly away from a NULL position referenced by a unique reference spline on the rotor shaft. By providing an adjustable location of the stator assembly within the housing, the magnetic axes within each generator shall be aligned to a predetermined and controlled tolerance between the generator interface mounting pin and the reference spline on the rotor shaft. Once magnetically aligned, each generator is essentially a line replaceable unit which may be readily mounted to any input of a multi-generator gearbox assembly with the assurance that the magnetic alignment will be within a predetermined tolerance.

24 CFR 3280.807 - Fixtures and appliances.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Fixtures and appliances. 3280.807... Fixtures and appliances. (a) Electrical materials, devices, appliances, fittings, and other equipment... fasten appliances when the manufactured home is in transit. (See § 3280.809.) (b) Specifically listed...

Cable clamp bolt fixture facilitates assembly in close quarters

NASA Technical Reports Server (NTRS)

Sunderland, G. H.

1967-01-01

Cable clamp bolt holding fixture facilitates forming of electrical cable runs in limited equipment space. The fixture engages the threads of the short clamp bolt through the clamp and maintains tension against clamp tendency to open while the operator installs the nut without difficulty.

46 CFR 129.410 - Lighting fixtures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL... electrical system operating at more than 50 volts must comply with UL 595, “Marine Type Electric Lighting... comply with UL 57, “Electric Lighting Fixtures,” UL 1570, “Fluorescent Lighting Fixtures,” UL 1571...

Initial Flight Tests of the NASA F-15B Propulsion Flight Test Fixture

NASA Technical Reports Server (NTRS)

Palumbo, Nathan; Moes, Timothy R.; Vachon, M. Jake

2002-01-01

Flights of the F-15B/Propulsion Flight Test Fixture (PFTF) with a Cone Drag Experiment (CDE) attached have been accomplished at NASA Dryden Flight Research Center. Mounted underneath the fuselage of an F-15B airplane, the PFTF provides volume for experiment systems and attachment points for propulsion experiments. A unique feature of the PFTF is the incorporation of a six-degree-of-freedom force balance. The force balance mounts between the PFTF and experiment and measures three forces and moments. The CDE has been attached to the force balance for envelope expansion flights. This experiment spatially and inertially simulates a large propulsion test article. This report briefly describes the F-15B airplane, the PFTF, and the force balance. A detailed description of the CDE is provided. Force-balance ground testing and stiffness modifications are described. Flight profiles and selected flight data from the envelope expansion flights are provided and discussed, including force-balance data, the internal PFTF thermal and vibration environment, a handling qualities assessment, and performance capabilities of the F-15B airplane with the PFTF installed.

Internal Temperature Control For Vibration Testers

NASA Technical Reports Server (NTRS)

Dean, Richard J.

1996-01-01

Vibration test fixtures with internal thermal-transfer capabilities developed. Made of aluminum for rapid thermal transfer. Small size gives rapid response to changing temperatures, with better thermal control. Setup quicker and internal ducting facilitates access to parts being tested. In addition, internal flows smaller, so less energy consumed in maintaining desired temperature settings.

78 FR 51463 - Energy Conservation Program: Energy Conservation Standards for Metal Halide Lamp Fixtures

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-20

... Efficiency at all Possible Voltages b. Posting the Highest and Lowest Efficiencies c. Test at Single Manufacturer-Declared Voltage d. Test at Highest-Rated Voltage e. Test on Input Voltage Based on Wattage and... at the highest voltage for which the ballast is designed to operate. [Dagger] P is defined as the...

1000539

NASA Image and Video Library

2010-04-13

AYMAN GIRGIS (EM10 MATERIALS TEST ENGINEER, JACOBS ESTS GROUP/JTI) AND ERIC EARHART (AEROSPACE ENGINEER, ER41 PROPULSION STRUCTURAL & DYNAMICS ANALYSIS BRANCH) DISCUSS DATA PRODUCED BY A UNIQUE MECHANICAL TEST SETUP THAT MEASURES STRAIN ON A SINGLE SAMPLE, USING TWO DIFFERENT TECHNIQUES AT THE SAME TIME. THE TEST FIXTURE HOLDS A SPECIMEN THAT REPRESENTS A LIQUID OXYGEN (LOX) BEARING FROM THE J2-X ENGINE.

10 CFR 431.324 - Uniform test method for the measurement of energy efficiency of metal halide ballasts.

Code of Federal Regulations, 2010 CFR

2010-01-01

... efficiency of metal halide ballasts. 431.324 Section 431.324 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT Metal Halide Lamp Ballasts and Fixtures Test Procedures § 431.324 Uniform test method for the measurement of energy efficiency of metal...

Braided Carbon Fiber Rope Flow Characteristics. Degree awarded by Utah Univ.

NASA Technical Reports Server (NTRS)

Heman, J. R. C.; McCool, A. (Technical Monitor)

2000-01-01

I am submitting the following technical subject for consideration as a thesis topic for the master degree: The reusable solid rocket motor (RSRM) nozzle internal joints are being evaluated for the incorporation of a carbon fiber rope (CFR) as a thermal barrier. The CFR is approximately 0.260 in. diameter and is composed of approximately 12,000 carbon fibers, woven in ten sheaths or layers. The CFR is manufactured by a sub-tier vendor and subsequently several of its manufacturing details are proprietary to that vendor. The CFR design intent is to prevent hot motor combustion products and slag from intruding into the joint scaling area while still approaching a vented joint design to avoid the detriments of gas jet impingement. As a member of the Heat Transfer section at Thiokol Propulsion, two main goals exist as part of this NASA funded design effort: (1) development of flow model through the CFR and (2) development of a heat transfer model through the CFR. While both models are needed and most probably interrelated, the gas flow model is being targeted as the subject matter. Essentially, the topic would be "Modeling of Gas Flow through a Braided Carbon Fiber Rope". An AIAA journal or conference paper is being considered through Thiokol/NASA as well. A sub-scale CFR flow test fixture was designed to simulate the relative levels of CFR compression. The test fixture provides the means to measure gas mass flow rate upstream of the CFR and the pressure and temperature both upstream and downstream of the CFR. The test fixture was designed to eliminate the possibility of dynamic gapping at the CFR location and provide minimal flow resistance to ambient for gases exiting the rope. The data collected in the experiment will be evaluated to define a permeability/flow resistance model. Two possibilities exist for the flow characteristics through the CFR from choked flow to strictly friction driven. A test matrix for evaluating the CFR has been compiled, which addresses both of these characteristics. The range of pressures to be tested covers a relatively low delta pressure where non-choked flow is impossible, while the high pressure shown is dictated by the RSRM joint operating pressure where choking is possible. The test matrix, was also designed for a range of rope compressions or test fixture gaps ranging from 0.025" to 0.070". These gaps are controlled by the range of RSRM full-scale hardware joint gaps that will be expected by virtue of the joint design.

A Better ARED Squat

NASA Technical Reports Server (NTRS)

Caldwell, E. E.; Newby, N. J.; Ploutz-Snyder, L.

2014-01-01

The 0-G ARED squat under loads the legs relative to the 1g ARED squat. In 1g the knee extensor/flexor muscles are primarily engaged due to the body's center of gravity is behind the knees during the motion of the squat. As body weight does not play a sufficient role 0 G, a crewmember's load exposure is limited by the load delivered by ARED through the exercise bar. Prescription loads for lowerbody resistance exercise in microgravity aim to include 1-G exercise bar load in addition to the crewmember's Earth body weight (BW); however, pressure points from the bar and the 1BW increased load at the shoulders translating to higher loads on the back have been a historical limitation for shoulders, requiring a decrease in exercise load at the start of the mission. Analogous to crewmembers, bed rest subjects report limitations of exercising with high loads on the back while performing squats on the horizontal exercise fixture (HEF), a custom exercise device that serves as an analog to 0-G ARED. Improvements for increasing loads on the HEF squat were suggested by distributing total exercise load between the hips and the bar1. The same is recommended for the 0-G ARED squat, with using current equipment on the ISS, which include the T2 running harness and T2 bungees. Quantification of this improvement has been accessed through computational modeling. The purpose of this study is to characterize joint torque during a squat with a distribution in exercise load on the ARED in 0 G. The analysis used existing models from NASA's Digital Astronaut Project. The biomechanics squat model was integrated with the ARED model and T2 bungees. The spring constant for the bungees were derived from ground testing. Forward dynamic simulation was performed for various conditions including anchor point attachments on the footplate of the ARED, bar load, hip load, and gravitational environment. The model confirms joint torques at knees is lower relative to 1G conditions primarily because the load delivery system is just with the exercise bar in 0 G. By distributing partial loads through use of the bungees to the hips joint-torque profiles were altered during a squat and provided options to enhance targeting lower-body loading in aims as for an improved countermeasure.

A Flexible Platform for Tribological Measurements on a Rheometer

NASA Astrophysics Data System (ADS)

Heyer, Patrick; Läuger, Jörg

2008-07-01

Tribology is the science and technology of interacting surfaces in relative motion, and embraces the study of friction, lubrication and wear. Contrary to rheology in tribology no fixed gap is maintained, but two fixtures are pressed together by a normal load. At certain sliding speeds between the two fixtures a hydrodynamic pressure builds up separating the two fixtures, i.e. the gap is changing as a function of the lubricant and the measuring conditions. However, a tribometer requires speed and normal force control as well as a torque measurement to acquire tribological data. An air bearing supported rotational rheometer allows the measurement of the same variables but in a broader range and with better accuracy and higher precision. This fact and the intension to perform both speed and torque controlled experiments to measure Stribeck curves as well as the static friction with one single instrument let to the idea to design an accessory turning a commercial available rheometer into a high resolution tribometer based on the ball on a pyramid or ball on three plates principle. Tribological measurements using the designed accessory on dry and oil lubricated systems have been conducted and illustrate the performance of the Rheo-Tribometer. Oil lubricated measurements of Stribeck curves and the static friction are used to compare the obtained results with measurements from more traditional tribometers. Dry systems, in which no additional lubricant is used, are important when for example the friction between two polymer surfaces or between a polymer and a metal surface are investigated, respectively. Exemplary results from such measurements under dry conditions are discussed. In addition tribological and rheological measurements on greases were performed and correlations between these measurements were found. By changing the plates from solid to being elastic measurements in the so-called soft elasto-hydrodynamic-lubrication (soft-EHL) regime are possible thus extending the range of applications to for example food and consumer products. In order to cover different applications beside the ball on pyramid setup different fixtures for the tribological attachment have been designed and will be described as well.

Self-Aligning Sensor-Mounting Fixture

NASA Technical Reports Server (NTRS)

Gilbert, Jeffrey L.; Mills, Rhonda J.

1991-01-01

Optical welding sensors replaced without realignment. Mounting fixture for optical weld-penetration sensor enables accurate and repeatable alignment. Simple and easy to use. Assembled on welding torch, it holds sensor securely and keeps it pointed toward weld pool. Designed for use on gas/tungsten arc-welding torch, fixture replaces multipiece bracket.

46 CFR 105.30-1 - Electrical fittings and fixtures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Electrical fittings and fixtures. 105.30-1 Section 105... VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Electrical Requirements § 105.30-1 Electrical fittings and fixtures. (a) In compartments or areas containing tanks or pumps handling other than...

46 CFR 105.30-1 - Electrical fittings and fixtures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Electrical fittings and fixtures. 105.30-1 Section 105... VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Electrical Requirements § 105.30-1 Electrical fittings and fixtures. (a) In compartments or areas containing tanks or pumps handling other than...

46 CFR 105.30-1 - Electrical fittings and fixtures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Electrical fittings and fixtures. 105.30-1 Section 105... VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Electrical Requirements § 105.30-1 Electrical fittings and fixtures. (a) In compartments or areas containing tanks or pumps handling other than...

46 CFR 105.30-1 - Electrical fittings and fixtures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Electrical fittings and fixtures. 105.30-1 Section 105... VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Electrical Requirements § 105.30-1 Electrical fittings and fixtures. (a) In compartments or areas containing tanks or pumps handling other than...

46 CFR 105.30-1 - Electrical fittings and fixtures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Electrical fittings and fixtures. 105.30-1 Section 105... VESSELS COMMERCIAL FISHING VESSELS DISPENSING PETROLEUM PRODUCTS Electrical Requirements § 105.30-1 Electrical fittings and fixtures. (a) In compartments or areas containing tanks or pumps handling other than...

24 CFR 3285.702 - Miscellaneous lights and fixtures.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Miscellaneous lights and fixtures... Equipment § 3285.702 Miscellaneous lights and fixtures. (a) When the home is installed, exterior lighting... canopy and the wiring outlet box. (d) Exterior lights. (1) The junction box covers must be removed and...

24 CFR 3285.702 - Miscellaneous lights and fixtures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 24 Housing and Urban Development 5 2012-04-01 2012-04-01 false Miscellaneous lights and fixtures... Equipment § 3285.702 Miscellaneous lights and fixtures. (a) When the home is installed, exterior lighting... canopy and the wiring outlet box. (d) Exterior lights. (1) The junction box covers must be removed and...

24 CFR 3285.702 - Miscellaneous lights and fixtures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Miscellaneous lights and fixtures... Equipment § 3285.702 Miscellaneous lights and fixtures. (a) When the home is installed, exterior lighting... canopy and the wiring outlet box. (d) Exterior lights. (1) The junction box covers must be removed and...

24 CFR 3285.702 - Miscellaneous lights and fixtures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Miscellaneous lights and fixtures... Equipment § 3285.702 Miscellaneous lights and fixtures. (a) When the home is installed, exterior lighting... canopy and the wiring outlet box. (d) Exterior lights. (1) The junction box covers must be removed and...

24 CFR 3285.702 - Miscellaneous lights and fixtures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Miscellaneous lights and fixtures... Equipment § 3285.702 Miscellaneous lights and fixtures. (a) When the home is installed, exterior lighting... canopy and the wiring outlet box. (d) Exterior lights. (1) The junction box covers must be removed and...

Development of a Prediction Model Based on RBF Neural Network for Sheet Metal Fixture Locating Layout Design and Optimization.

PubMed

Wang, Zhongqi; Yang, Bo; Kang, Yonggang; Yang, Yuan

2016-01-01

Fixture plays an important part in constraining excessive sheet metal part deformation at machining, assembly, and measuring stages during the whole manufacturing process. However, it is still a difficult and nontrivial task to design and optimize sheet metal fixture locating layout at present because there is always no direct and explicit expression describing sheet metal fixture locating layout and responding deformation. To that end, an RBF neural network prediction model is proposed in this paper to assist design and optimization of sheet metal fixture locating layout. The RBF neural network model is constructed by training data set selected by uniform sampling and finite element simulation analysis. Finally, a case study is conducted to verify the proposed method.

Development of a Prediction Model Based on RBF Neural Network for Sheet Metal Fixture Locating Layout Design and Optimization

PubMed Central

Wang, Zhongqi; Yang, Bo; Kang, Yonggang; Yang, Yuan

2016-01-01

Fixture plays an important part in constraining excessive sheet metal part deformation at machining, assembly, and measuring stages during the whole manufacturing process. However, it is still a difficult and nontrivial task to design and optimize sheet metal fixture locating layout at present because there is always no direct and explicit expression describing sheet metal fixture locating layout and responding deformation. To that end, an RBF neural network prediction model is proposed in this paper to assist design and optimization of sheet metal fixture locating layout. The RBF neural network model is constructed by training data set selected by uniform sampling and finite element simulation analysis. Finally, a case study is conducted to verify the proposed method. PMID:27127499

In vitro resistance to fracture of roots obturated with Resilon or gutta-percha.

PubMed

Monteiro, Jeanne; de Ataide, Ida de Noronha; Chalakkal, Paul; Chandra, Pavan Kumar

2011-06-01

There have been varied results from studies comparing postendodontic fracture resistance between teeth obturated with Resilon or gutta-percha. This study was performed to evaluate the fracture resistance of roots obturated by using Resilon (RealSeal system) or gutta-percha (with AH Plus sealer). Eighty extracted human mandibular single-rooted premolars stored in 10% formalin were used in the study. They were prepared by using a crown-down technique, debrided with NaOCl, ethylenediaminetetraacetic acid, and sterile water and divided into 4 groups. Obturation was performed by using the lateral condensation method. The negative control group consisted of unfilled specimens, and the positive control group consisted of those obturated with flowable, dual-cure composite resin. All root specimens were stored for 2 weeks in 100% humidity to allow complete setting of the sealer. Each specimen was mounted in acrylic in a polyvinyl ring and tested for fracture resistance with the Universal testing machine. The loading fixture of the machine was mounted with its spherical tip aligned with the center of the canal opening of each root. A vertical loading force was applied until it fractured the root. The force values were subjected to statistical analysis including analysis of variance and Fisher least significant difference testing. Teeth obturated with Resilon were more resistant to fracture than those obturated with gutta-percha. The difference was found to be highly significant (P=.00001). Resilon increased the resistance to fracture of single-rooted teeth in vitro. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Voyager electronic parts radiation program. Volume 2: Test requirements and procedures

NASA Technical Reports Server (NTRS)

Stanley, A. G.; Martin, K. E.; Price, W. E.

1978-01-01

Documents are presented outlining the conditions and requirements of the test program. The Appendixes are as follows: appendix A -- Electron Simulation Radiation Test Specification for Voyager Electronic Parts and Devices, appendix B -- Electronic Piece-Part Testing Program for Voyager, appendix C -- Test Procedure for Radiation Screening of Voyager Piece Parts, appendix D -- Boeing In Situ Test Fixture, and appendix E -- Irradiate - Anneal (IRAN) Screening Documents.

Slicing of Silicon into Sheet Material: Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low Cost Silicon Solar Array Project

NASA Technical Reports Server (NTRS)

Fleming, J. R.

1979-01-01

Testing of low cost low suspension power slurry vehicles is presented. Cutting oils are unlikely to work, but a mineral oil with additives should be workable. Two different abrasives were tested. A cheaper silicon carbide from Norton gave excellent results except for excessive kerf loss: the particles were too big. An abrasive treated for lubricity showed no lubricity improvement in mineral oil vehicle. The bounce fixture was tested for the first time under constant cut rate conditions (rather than constant force). Although the cut was not completed before the blades broke, the blade lifetime of thin (100 micrometer) blades was 120 times the lifetime without the fixture. The large prototype saw completed a successful run, producing 90% cutting yield (849 wafers) at 20 wafers/cm. Although inexperience with large numbers of wafers caused cleaning breakage to reduce this yield to 74%, the yield was high enough that the concept of the large saw is proven workable.

Open core control software for surgical robots.

PubMed

Arata, Jumpei; Kozuka, Hiroaki; Kim, Hyung Wook; Takesue, Naoyuki; Vladimirov, B; Sakaguchi, Masamichi; Tokuda, Junichi; Hata, Nobuhiko; Chinzei, Kiyoyuki; Fujimoto, Hideo

2010-05-01

In these days, patients and doctors in operation room are surrounded by many medical devices as resulting from recent advancement of medical technology. However, these cutting-edge medical devices are working independently and not collaborating with each other, even though the collaborations between these devices such as navigation systems and medical imaging devices are becoming very important for accomplishing complex surgical tasks (such as a tumor removal procedure while checking the tumor location in neurosurgery). On the other hand, several surgical robots have been commercialized, and are becoming common. However, these surgical robots are not open for collaborations with external medical devices in these days. A cutting-edge "intelligent surgical robot" will be possible in collaborating with surgical robots, various kinds of sensors, navigation system and so on. On the other hand, most of the academic software developments for surgical robots are "home-made" in their research institutions and not open to the public. Therefore, open source control software for surgical robots can be beneficial in this field. From these perspectives, we developed Open Core Control software for surgical robots to overcome these challenges. In general, control softwares have hardware dependencies based on actuators, sensors and various kinds of internal devices. Therefore, these control softwares cannot be used on different types of robots without modifications. However, the structure of the Open Core Control software can be reused for various types of robots by abstracting hardware dependent parts. In addition, network connectivity is crucial for collaboration between advanced medical devices. The OpenIGTLink is adopted in Interface class which plays a role to communicate with external medical devices. At the same time, it is essential to maintain the stable operation within the asynchronous data transactions through network. In the Open Core Control software, several techniques for this purpose were introduced. Virtual fixture is well known technique as a "force guide" for supporting operators to perform precise manipulation by using a master-slave robot. The virtual fixture for precise and safety surgery was implemented on the system to demonstrate an idea of high-level collaboration between a surgical robot and a navigation system. The extension of virtual fixture is not a part of the Open Core Control system, however, the function such as virtual fixture cannot be realized without a tight collaboration between cutting-edge medical devices. By using the virtual fixture, operators can pre-define an accessible area on the navigation system, and the area information can be transferred to the robot. In this manner, the surgical console generates the reflection force when the operator tries to get out from the pre-defined accessible area during surgery. The Open Core Control software was implemented on a surgical master-slave robot and stable operation was observed in a motion test. The tip of the surgical robot was displayed on a navigation system by connecting the surgical robot with a 3D position sensor through the OpenIGTLink. The accessible area was pre-defined before the operation, and the virtual fixture was displayed as a "force guide" on the surgical console. In addition, the system showed stable performance in a duration test with network disturbance. In this paper, a design of the Open Core Control software for surgical robots and the implementation of virtual fixture were described. The Open Core Control software was implemented on a surgical robot system and showed stable performance in high-level collaboration works. The Open Core Control software is developed to be a widely used platform of surgical robots. Safety issues are essential for control software of these complex medical devices. It is important to follow the global specifications such as a FDA requirement "General Principles of Software Validation" or IEC62304. For following these regulations, it is important to develop a self-test environment. Therefore, a test environment is now under development to test various interference in operation room such as a noise of electric knife by considering safety and test environment regulations such as ISO13849 and IEC60508. The Open Core Control software is currently being developed software in open-source manner and available on the Internet. A communization of software interface is becoming a major trend in this field. Based on this perspective, the Open Core Control software can be expected to bring contributions in this field.

Validation of Force Limited Vibration Testing at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Rice, Chad; Buehrle, Ralph D.

2003-01-01

Vibration tests were performed to develop and validate the forced limited vibration testing capability at the NASA Langley Research Center. The force limited vibration test technique has been utilized at the Jet Propulsion Laboratory and other NASA centers to provide more realistic vibration test environments for aerospace flight hardware. In standard random vibration tests, the payload is mounted to a rigid fixture and the interface acceleration is controlled to a specified level based on a conservative estimate of the expected flight environment. In force limited vibration tests, both the acceleration and force are controlled at the mounting interface to compensate for differences between the flexible flight mounting and rigid test fixture. This minimizes the over test at the payload natural frequencies and results in more realistic forces being transmitted at the mounting interface. Force and acceleration response data was provided by NASA Goddard Space Flight Center for a test article that was flown in 1998 on a Black Brant sounding rocket. The measured flight interface acceleration data was used as the reference acceleration spectrum. Using this acceleration spectrum, three analytical methods were used to estimate the force limits. Standard random and force limited vibration tests were performed and the results are compared with the flight data.

Arc-Second Alignment of International X-Ray Observatory Mirror Segments in a Fixed Structure

NASA Technical Reports Server (NTRS)

Evans, Tyler, C.; Chan, Kai-Wing; Saha, Timo T.

2010-01-01

The optics for the International X-Ray Observatory (IXO) require alignment and integration of about fourteen thousand thin mirror segments to achieve the mission goal of 3.0 square meters of effective area at 1.25 keV with an angular resolution of five arc-seconds. These mirror segments are 0.4 mm thick, and 200 to 400 mm in size, which makes it hard to meet the strict angular resolution requirement of 5 arc-seconds for the telescope. This paper outlines the precise alignment, verification testing, and permanent bonding techniques developed at NASA's Goddard Space Flight Center (GSFC). These techniques are used to overcome the challenge of transferring thin mirror segments from a temporary mount to a fixed structure with arc-second alignment and minimal figure distortion. Recent advances in technology development in addition to the automation of several processes have produced significant results. Recent advances in the mirror fixture process known as the suspension mount has allowed for a mirror to be mounted to a fixture with minimal distortion. Once on the fixture, mirror segments have been aligned to around 5 arc-seconds which is halfway to the goal of 2.5 arc-seconds per mirror segment. This paper will highlight the recent advances in alignment, testing, and permanent bonding techniques as well as the results they have produced.

Transport of LCLS-II 1.3 Ghz cryomodule to SLAC

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

McGee, M. W.; Arkan, T.; Peterson, T.

2016-06-30

In a partnership with SLAC National Accelerator Laboratory (SLAC) and Jefferson Lab, Fermilab will assemble and test 17 of the 35 total 1.3 GHz cryomodules for the Linac Coherent Light Source II (LCLS-II) Project. These include a prototype built and delivered by each Lab. Another two 3.9 GHz cryomodules will be built, tested and transported by Fermilab to SLAC. Each assembly will be transported over-the-road from Fermilab or Jefferson Lab using specific routes to SLAC. The transport system consists of a base frame, isolation fixture and upper protective truss. The strongback cryomodule lifting fixture is described along with other supportingmore » equipment used for both over-the-road transport and local (on-site) transport at Fermilab. Initially, analysis of fragile components and stability studies will be performed in order to assess the risk associated with over-the-road transport of a fully assembled cryomodule.« less

Macroscopic and microscopic evaluation of a new implant design supporting immediately loaded full arch rehabilitation

PubMed Central

Tetè, Stefano; Zizzari, Vincenzo; De Carlo, Alessandro; Sinjari, Bruna; Gherlone, Enrico

2012-01-01

Summary The purpose of this study is to evaluate macroscopic and microscopic appearance of a new implant design, with particular emphasis given to the type of prosthesis connection. Two dental implants of the same type (Torque Type®, WinSix®, BioSAFin. S.r.l. - Ancona, Italy), with sandblasted and acid etched surfaces (Micro Rough Surface®), but differing from each other for the prosthesis connection system, were examined by scanning electron microscope (SEM) analysis at different magnifications: TTI implant, with a hexagonal internal connection, and TTX implant, with a hexagonal external connection. SEM analysis showed that the Torque Type® implant is characterized by a truncated cone shape with tapered tips. The implant body showed a double loop thread and double pitch with blunt tips. For both types of connection, the implant neck was 0.7 mm in height with a 3% taper. This implant design may be able to guarantee osteotomic properties at the time of insertion in a surgical site suitably prepared, a facilitated screwing, thanks to the thread pitch and to the broad and deep draining grooves, thereby ensuring a good primary stability. The different connection design appears defined and precise, in order to ensure a good interface between the fixture and the prosthetic components. Therefore, this design appears to be particularly suitable in cases where a good primary stability is necessary and a precise coupling between endosseous and prosthetic components, as it allows an easy insertion of the fixture even in conditions of reduced bone availability, and in cases of immediately loaded full-arch rehabilitations. PMID:23087785

Macroscopic and microscopic evaluation of a new implant design supporting immediately loaded full arch rehabilitation.

PubMed

Tetè, Stefano; Zizzari, Vincenzo; De Carlo, Alessandro; Sinjari, Bruna; Gherlone, Enrico

2012-04-01

The purpose of this study is to evaluate macroscopic and microscopic appearance of a new implant design, with particular emphasis given to the type of prosthesis connection. Two dental implants of the same type (Torque Type(®), WinSix(®), BioSAFin. S.r.l. - Ancona, Italy), with sandblasted and acid etched surfaces (Micro Rough Surface(®)), but differing from each other for the prosthesis connection system, were examined by scanning electron microscope (SEM) analysis at different magnifications: TTI implant, with a hexagonal internal connection, and TTX implant, with a hexagonal external connection. SEM analysis showed that the Torque Type(®) implant is characterized by a truncated cone shape with tapered tips. The implant body showed a double loop thread and double pitch with blunt tips. For both types of connection, the implant neck was 0.7 mm in height with a 3% taper. This implant design may be able to guarantee osteotomic properties at the time of insertion in a surgical site suitably prepared, a facilitated screwing, thanks to the thread pitch and to the broad and deep draining grooves, thereby ensuring a good primary stability. The different connection design appears defined and precise, in order to ensure a good interface between the fixture and the prosthetic components. Therefore, this design appears to be particularly suitable in cases where a good primary stability is necessary and a precise coupling between endosseous and prosthetic components, as it allows an easy insertion of the fixture even in conditions of reduced bone availability, and in cases of immediately loaded full-arch rehabilitations.

Wear, strength, modulus and hardness of CAD/CAM restorative materials.

PubMed

Lawson, Nathaniel C; Bansal, Ritika; Burgess, John O

2016-11-01

To measure the mechanical properties of several CAD/CAM materials, including lithium disilicate (e.max CAD), lithium silicate/zirconia (Celtra Duo), 3 resin composites (Cerasmart, Lava Ultimate, Paradigm MZ100), and a polymer infiltrated ceramic (Enamic). CAD/CAM blocks were sectioned into 2.5mm×2.5mm×16mm bars for flexural strength and elastic modulus testing and 4mm thick blocks for hardness and wear testing. E.max CAD and half the Celtra Duo specimens were treated in a furnace. Flexural strength specimens (n=10) were tested in a three-point bending fixture. Vickers microhardness (n=2, 5 readings per specimen) was measured with a 1kg load and 15s dwell time. The CAD/CAM materials as well as labial surfaces of human incisors were mounted in the UAB wear device. Cusps of human premolars were mounted as antagonists. Specimens were tested for 400,000 cycles at 20N force, 2mm sliding distance, 1Hz frequency, 24°C, and 33% glycerin lubrication. Volumetric wear and opposing enamel wear were measured with non-contact profilometry. Data were analyzed with 1-way ANOVA and Tukey post-hoc analysis (alpha=0.05). Specimens were observed with SEM. Properties were different for each material (p<0.01). E.max CAD and Celtra Duo were generally stronger, stiffer, and harder than the other materials. E.max CAD, Celtra Duo, Enamic, and enamel demonstrated signs of abrasive wear, whereas Cerasmart, Lava Ultimate, Paradigm MZ100 demonstrated signs of fatigue. Resin composite and resin infiltrated ceramic materials have demonstrated adequate wear resistance for load bearing restorations, however, they will require at least similar material thickness as lithium disilicate restorations due to their strength. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Long-term evaluation of solid oxide fuel cell candidate materials in a 3-cell generic short stack fixture, Part II: sealing glass stability, microstructure and interfacial reactions.

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

Chou, Y. S.; Stevenson, Jeffry W.; Choi, Jung-Pyung

2014-03-15

A generic solid oxide fuel cell stack test fixture was developed to evaluate candidate materials and processing methods under realistic conditions. Part I of the work addressed the stack fixture, seal system and cell performance of a 3-cell short stack tested at 800oC for 6000h. Commercial NiO-YSZ anode-supported thin YSZ electrolyte cells with LSM cathodes were used for assessment and were tested in constant current mode with dilute (~50% H2) fuel versus air. Part II of the work examined the sealing glass stability, microstructure development, interfacial reactions, and volatility issues. Part III of the work investigated the stability of Ce-(Mn,Co)more » spinel coating, AISI441 metallic interconnect, alumina coating, and cell degradation. After 6000h of testing, the refractory sealing glass YSO77 (Ba-Sr-Y-B-Si) showed desirable chemical compatibility with YSZ electrolyte in that no discernable interfacial reaction was identified, consistent with thermodynamic calculations. In addition, no glass penetration into the thin electrolyte was observed. At the aluminized AISI441 interface, the protective alumina coating appeared to be corroded by the sealing glass. Air side interactions appeared to be more severe than fuel side interactions. Metal species such as Cr, Mn, and Fe were detected in the glass, but were limited to the vicinity of the interface. No alkaline earth chromates were found at the air side. Volatility was also studied in a similar glass and weight loss in a wet reducing environment was determined. Using the steady-state volatility data, the life time (40,000h) weight loss of refractory sealing glass YSO77 was estimated to be less than 0.1 wt%.« less

75 FR 5544 - Energy Conservation Program: Energy Conservation Standards for Metal Halide Lamp Fixtures: Public...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-03

...-2009-BT-STD-0018] RIN 1904-AC00 Energy Conservation Program: Energy Conservation Standards for Metal... certain metal halide lamp fixtures. This document announces that the period for submitting comments on the... identify the Framework Document for energy conservation standards for metal halide lamp fixtures and...

30 CFR 56.3203 - Rock fixtures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Rock fixtures. 56.3203 Section 56.3203 Mineral... § 56.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall— (1) Obtain a manufacturer's...

30 CFR 56.3203 - Rock fixtures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Rock fixtures. 56.3203 Section 56.3203 Mineral... § 56.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall— (1) Obtain a manufacturer's...

30 CFR 57.3203 - Rock fixtures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral... Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall...

30 CFR 56.3203 - Rock fixtures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Rock fixtures. 56.3203 Section 56.3203 Mineral... § 56.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall— (1) Obtain a manufacturer's...

30 CFR 57.3203 - Rock fixtures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral... Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall...

30 CFR 57.3203 - Rock fixtures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Rock fixtures. 57.3203 Section 57.3203 Mineral... Support-Surface and Underground § 57.3203 Rock fixtures. (a) For rock bolts and accessories addressed in ASTM F432-95, “Standard Specification for Roof and Rock Bolts and Accessories,” the mine operator shall...

40 CFR 429.160 - Applicability; description of the wood furniture and fixture production without water wash spray...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the wood... GUIDELINES AND STANDARDS TIMBER PRODUCTS PROCESSING POINT SOURCE CATEGORY Wood Furniture and Fixture... Applicability; description of the wood furniture and fixture production without water wash spray booth(s) or...

40 CFR 429.160 - Applicability; description of the wood furniture and fixture production without water wash spray...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the wood... GUIDELINES AND STANDARDS TIMBER PRODUCTS PROCESSING POINT SOURCE CATEGORY Wood Furniture and Fixture... Applicability; description of the wood furniture and fixture production without water wash spray booth(s) or...

49 CFR 571.108 - Standard No. 108; Lamps, reflective devices, and associated equipment.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the headlamp. Headlamp test fixture means a device designed to support a headlamp or headlamp assembly... to 1% of design life, or other equivalent method. Semiautomatic headlamp beam switching device is one... signal lamp must be designed to conform to the performance requirements of the vibration test, moisture...

49 CFR 571.108 - Standard No. 108; Lamps, reflective devices, and associated equipment.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the headlamp. Headlamp test fixture means a device designed to support a headlamp or headlamp assembly... to 1% of design life, or other equivalent method. Semiautomatic headlamp beam switching device is one... signal lamp must be designed to conform to the performance requirements of the vibration test, moisture...

Piezoelectric Response of Ferroelectric Ceramics Under Mechanical Stress

DTIC Science & Technology

2015-09-17

dynamic response, and predict mechanical breakdown of electronic materials, numerous testing techniques such as very high-g machines , drop towers...James C. Hierholzer for building the custom test fixture, Michael D. Craft for his help with static capacitance measurements, Bryan J. Turner, Scott D...ISOLA 370HR Board Specimen Test Set-Up . . . . . . . . . . . . . . . . . . 59 3.3 Printed Circuit Board Electrical Layout

Case study: Fixture water use and drinking water quality in a new residential green building.

PubMed

Salehi, Maryam; Abouali, Mohammad; Wang, Mian; Zhou, Zhi; Nejadhashemi, Amir Pouyan; Mitchell, Jade; Caskey, Stephen; Whelton, Andrew J

2018-03-01

Residential plumbing is critical for the health and safety of populations worldwide. A case study was conducted to understand fixture water use, drinking water quality and their possible link, in a newly plumbed residential green building. Water use and water quality were monitored at four in-building locations from September 2015 through December 2015. Once the home was fully inhabited average water stagnation periods were shortest at the 2nd floor hot fixture (90 percentile of 0.6-1.2 h). The maximum water stagnation time was 72.0 h. Bacteria and organic carbon levels increased inside the plumbing system compared to the municipal tap water entering the building. A greater amount of bacteria was detected in hot water samples (6-74,002 gene copy number/mL) compared to cold water (2-597 gene copy number/mL). This suggested that hot water plumbing promoted greater microbial growth. The basement fixture brass needle valve may have caused maximum Zn (5.9 mg/L), Fe (4.1 mg/L), and Pb (23 μg/L) levels compared to other fixture water samples (Zn ≤ 2.1 mg/L, Fe ≤ 0.5 mg/L and Pb ≤ 8 μg/L). At the basement fixture, where the least amount of water use events occurred (cold: 60-105, hot: 21-69 event/month) compared to the other fixtures in the building (cold: 145-856, hot: 326-2230 event/month), greater organic carbon, bacteria, and heavy metal levels were detected. Different fixture use patterns resulted in disparate water quality within a single-family home. The greatest drinking water quality changes were detected at the least frequently used fixture. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of surface treatment on stress distribution in immediately loaded dental implants--a 3D finite element analysis.

PubMed

Bahrami, Babak; Shahrbaf, Shirin; Mirzakouchaki, Behnam; Ghalichi, Farzan; Ashtiani, Mohammed; Martin, Nicolas

2014-04-01

To investigate, by means of FE analysis, the effect of surface roughness treatments on the distribution of stresses at the bone-implant interface in immediately loaded mandibular implants. An accurate, high resolution, digital replica model of bone structure (cortical and trabecular components) supporting an implant was created using CT scan data and image processing software (Mimics 13.1; Materialize, Leuven, Belgium). An anatomically accurate 3D model of a mandibular-implant complex was created using a professional 3D-CAD modeller (SolidWorks, DassaultSystèmes Solid Works Corp; 2011). Finite element models were created with one of the four roughness treatments on the implant fixture surface. Of these, three were surface treated to create a uniform coating determined by the coefficient of friction (μ); these were either (1) plasma sprayed or porous-beaded (μ=1.0), (2) sandblasted (μ=0.68) or (3) polished (μ=0.4). The fourth implant had a novel two-part surface roughness consisting of a coronal polished component (μ=0.4) interfacing with the cortical bone, and a body plasma treated surface component (μ=1) interfacing with the trabecular bone. Finite element stress analysis was carried out under vertical and lateral forces. This investigation showed that the type of surface treatment on the implant fixture affects the stress at the bone-implant interface of an immediately loaded implant complex. Von Mises stress data showed that the two-part surface treatment created the better stress distribution at the implant-bone interface. The results from this FE computational analysis suggest that the proposed two-part surface treatment for IL implants creates lower stresses than single uniform treatments at the bone-implant interface, which might decrease peri-implant bone loss. Future investigations should focus on mechanical and clinical validation of these FE results. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Torque-Limiting Manipulation Device

NASA Technical Reports Server (NTRS)

Moetteli, John B. (Inventor)

1999-01-01

A device for manipulating a workpiece in space includes a fixture, a stanchion assembly, a manipulation mechanism, an actuation mechanism, and a reaction mechanism. The fixture has an end onto which the workpiece affixes. The stanchion assembly has an upper and a lower end. The manipulation mechanism connects the fixture and the upper end of the stanchion assembly. The lower end of the stanchion assembly mounts, via probe and a socket, to a structure. The actuation mechanism operably connects to the manipulation mechanism, and moves the fixture in space. The reaction mechanism provides a point through which force inputs into the actuation mechanism may react.

Integrated calibration sphere and calibration step fixture for improved coordinate measurement machine calibration

DOEpatents

Clifford, Harry J [Los Alamos, NM

2011-03-22

A method and apparatus for mounting a calibration sphere to a calibration fixture for Coordinate Measurement Machine (CMM) calibration and qualification is described, decreasing the time required for such qualification, thus allowing the CMM to be used more productively. A number of embodiments are disclosed that allow for new and retrofit manufacture to perform as integrated calibration sphere and calibration fixture devices. This invention renders unnecessary the removal of a calibration sphere prior to CMM measurement of calibration features on calibration fixtures, thereby greatly reducing the time spent qualifying a CMM.

Fixture for supporting and aligning a sample to be analyzed in an x-ray diffraction apparatus

DOEpatents

Green, L.A.; Heck, J.L. Jr.

1985-04-23

A fixture is provided for supporting and aligning small samples of material on a goniometer for x-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the x-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an x-ray diffraction apparatus previously limited to the analysis of much larger samples.

Fixture for supporting and aligning a sample to be analyzed in an X-ray diffraction apparatus

DOEpatents

Green, Lanny A.; Heck, Jr., Joaquim L.

1987-01-01

A fixture is provided for supporting and aligning small samples of material on a goniometer for X-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the X-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an X-ray diffraction apparatus previously limited to the analysis of much larger samples.

High-strain rate tensile characterization of graphite platelet reinforced vinyl ester based nanocomposites using split-Hopkinson pressure bar

NASA Astrophysics Data System (ADS)

Pramanik, Brahmananda

The dynamic response of exfoliated graphite nanoplatelet (xGnP) reinforced and carboxyl terminated butadiene nitrile (CTBN) toughened vinyl ester based nanocomposites are characterized under both dynamic tensile and compressive loading. Dynamic direct tensile tests are performed applying the reverse impact Split Hopkinson Pressure Bar (SHPB) technique. The specimen geometry for tensile test is parametrically optimized by Finite Element Analysis (FEA) using ANSYS Mechanical APDLRTM. Uniform stress distribution within the specimen gage length has been verified using high-speed digital photography. The on-specimen strain gage installation is substituted by a non-contact Laser Occlusion Expansion Gage (LOEG) technique for infinitesimal dynamic tensile strain measurements. Due to very low transmitted pulse signal, an alternative approach based on incident pulse is applied for obtaining the stress-time history. Indirect tensile tests are also performed combining the conventional SHPB technique with Brazilian disk test method for evaluating cylindrical disk specimens. The cylindrical disk specimen is held snugly in between two concave end fixtures attached to the incident and transmission bars. Indirect tensile stress is estimated from the SHPB pulses, and diametrical transverse tensile strain is measured using LOEG. Failure diagnosis using high-speed digital photography validates the viability of utilizing this indirect test method for characterizing the tensile properties of the candidate vinyl ester based nanocomposite system. Also, quasi-static indirect tensile response agrees with previous investigations conducted using the traditional dog-bone specimen in quasi-static direct tensile tests. Investigation of both quasi-static and dynamic indirect tensile test responses show the strain rate effect on the tensile strength and energy absorbing capacity of the candidate materials. Finally, the conventional compressive SHPB tests are performed. It is observed that both strength and energy absorbing capacity of these candidate material systems are distinctively less under dynamic tension than under compressive loading. Nano-reinforcement appears to marginally improve these properties for pure vinyl ester under dynamic tension, although it is found to be detrimental under dynamic compression.

Research of the value of linear distortion of renewable surface of part during rotary processing of bulky items without dismantling unit

NASA Astrophysics Data System (ADS)

Bondarenko, J. A.; Fedorenko, M. A.; Pogonin, A. A.

2018-03-01

The loading and unloading units and grinding mills of raw devices have internal cone type or pipe screw perceive load of incoming and outgoing material. The main part of the support assembly is a pin. Mounting seats for the pipe screws cone have traces of deformation and work hardening, while they themselves have wear of pins and deformation of the inner and outer cylindrical working surface. In the mill body, there are constantly acting dynamic forces causing vibration, which are transmitted to the stud and inner accelerating elements. Under the influence of stress and vibration, the housing spigot is in the stress-compressed state and stretched vertically and horizontally. As a result, the insertion element is deformed and weakened in the fixture. A moving element appears in the gap leading to the fact that it drops lfeedstock and under the influence of variable loads it is destroyed, as well as the seating surfaces of the insert pin member.

Panel Stiffener Debonding Analysis using a Shell/3D Modeling Technique

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Ratcliffe, James G.; Minguet, Pierre J.

2008-01-01

A shear loaded, stringer reinforced composite panel is analyzed to evaluate the fidelity of computational fracture mechanics analyses of complex structures. Shear loading causes the panel to buckle. The resulting out -of-plane deformations initiate skin/stringer separation at the location of an embedded defect. The panel and surrounding load fixture were modeled with shell elements. A small section of the stringer foot, web and noodle as well as the panel skin near the delamination front were modeled with a local 3D solid model. Across the width of the stringer fo to, the mixed-mode strain energy release rates were calculated using the virtual crack closure technique. A failure index was calculated by correlating the results with a mixed-mode failure criterion of the graphite/epoxy material. The objective was to study the effect of the fidelity of the local 3D finite element model on the computed mixed-mode strain energy release rates and the failure index.

Panel-Stiffener Debonding and Analysis Using a Shell/3D Modeling Technique

NASA Technical Reports Server (NTRS)

Krueger, Ronald; Ratcliffe, James G.; Minguet, Pierre J.

2007-01-01

A shear loaded, stringer reinforced composite panel is analyzed to evaluate the fidelity of computational fracture mechanics analyses of complex structures. Shear loading causes the panel to buckle. The resulting out-of-plane deformations initiate skin/stringer separation at the location of an embedded defect. The panel and surrounding load fixture were modeled with shell elements. A small section of the stringer foot, web and noodle as well as the panel skin near the delamination front were modeled with a local 3D solid model. Across the width of the stringer foot, the mixed-mode strain energy release rates were calculated using the virtual crack closure technique. A failure index was calculated by correlating the results with a mixed-mode failure criterion of the graphite/epoxy material. The objective was to study the effect of the fidelity of the local 3D finite element model on the computed mixed-mode strain energy release rates and the failure index.

Cost Effective Prototyping

NASA Technical Reports Server (NTRS)

Wickman, Jerry L.; Kundu, Nikhil K.

1996-01-01

This laboratory exercise seeks to develop a cost effective prototype development. The exercise has the potential of linking part design, CAD, mold development, quality control, metrology, mold flow, materials testing, fixture design, automation, limited parts production and other issues as related to plastics manufacturing.

Fixture For Mounting A Pressure Sensor

NASA Technical Reports Server (NTRS)

Cagle, Christopher M.

1995-01-01

Fixture for mounting pressure sensor in aerodynamic model simplifies task of removal and replacement of sensor in event sensor becomes damaged. Makes it unnecessary to dismantle model. Also minimizes any change in aerodynamic characteristics of model in event of replacement. Removable pressure sensor installed in fixture in wall of model. Wires from sensor pass through channel under surface.

40 CFR 429.170 - Applicability; description of the wood furniture and fixture production with water wash spray...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the wood... GUIDELINES AND STANDARDS TIMBER PRODUCTS PROCESSING POINT SOURCE CATEGORY Wood Furniture and Fixture...; description of the wood furniture and fixture production with water wash spray booth(s) or with laundry...

40 CFR 429.170 - Applicability; description of the wood furniture and fixture production with water wash spray...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the wood... GUIDELINES AND STANDARDS TIMBER PRODUCTS PROCESSING POINT SOURCE CATEGORY Wood Furniture and Fixture...; description of the wood furniture and fixture production with water wash spray booth(s) or with laundry...

Retention and wear behaviors of two implant overdenture stud-type attachments at different implant angulations.

PubMed

Choi, Jae-Won; Bae, Ji-Hyeon; Jeong, Chang-Mo; Huh, Jung-Bo

2017-05-01

Implant angulation should be considered when selecting an attachment. Some in vitro studies have investigated the relationship between implant angulation and changes in the retention force of the stud attachment, but few studies have evaluated the effect of cyclic loading and repeated cycles of insertion and removal on the stud attachment. The purpose of this in vitro study was to evaluate the effects of implant angulation on the retentive characteristics of overdentures with 2 different stud attachments, an experimental system and O-rings in red and orange, after cyclic loading and repeated insertion and removal cycles. The canine region of a mandibular experimental model was fitted with 2 implant fixtures with 2 different stud attachment systems at implant angulations of 0, 15, or 30 degrees. A mastication simulator was used to simulate cyclic loading, and a universal testing machine was used to evaluate retentive force changes after repeated insertion and removal cycles. To simulate the numbers of mastication and insertion and removal cycles per annum, 400000 cyclic loadings and 1080 insertion and removal cycles were performed. Wear patterns and attachment surface deformations were evaluated by scanning electron microscopy. Data were analyzed using the Kruskal-Wallis test, Mann-Whitney U test with Bonferroni correction (α=.05/3=.017), and the paired-sample Student t test (α=.05). When retentive forces before and after testing were compared, O-ring showed significant retention loss at all implant angulations (P<.001). In contrast, the experimental system showed little retention loss in the 0- and 15-degree models (P>.05), whereas the 30-degree model showed a significant increase in retentive force (P=.001). At all implant angulations, retention loss increased significantly for the orange O-ring, followed by the red O-ring, and the experimental system (P<.001). Scanning electron microscopy analysis showed more intense wear in the matrix than the patrix (abutment that matches to matrix) and more severe wear and deformation of the O-ring rubber matrix than of the experimental zirconia ball. Upon completion of the experiment, wear and deformation were found for all attachment systems. Even when implants are not installed in parallel, the experimental system can be used without involving great loss of retention. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Lighting system combining daylight concentrators and an artificial source

DOEpatents

Bornstein, Jonathan G.; Friedman, Peter S.

1985-01-01

A combined lighting system for a building interior includes a stack of luminescent solar concentrators (LSC), an optical conduit made of preferably optical fibers for transmitting daylight from the LSC stack, a collimating lens set at an angle, a fixture for receiving the daylight at one end and for distributing the daylight as illumination inside the building, an artificial light source at the other end of the fixture for directing artifical light into the fixture for distribution as illumination inside the building, an automatic dimmer/brightener for the artificial light source, and a daylight sensor positioned near to the LSC stack for controlling the automatic dimmer/brightener in response to the daylight sensed. The system also has a reflector positioned behind the artificial light source and a fan for exhausting heated air out of the fixture during summer and for forcing heated air into the fixture for passage into the building interior during winter.

Experimental study on surface wrinkling of silicon monoxide film on compliant substrate under thermally induced loads

NASA Astrophysics Data System (ADS)

Li, Chuanwei; Kong, Yingxiao; Jiang, Wenchong; Wang, Zhiyong; Li, Linan; Wang, Shibin

2017-06-01

The wrinkling of a silicon monoxide thin film on a compliant poly(dimethylsiloxane) (PDMS) substrate structure was experimentally investigated in this study. The self-expansion effect of PDMS during film deposition was utilized to impose a pretensile strain on the structure through a specially made fixture. A laser scanning confocal microscope (LSCM) system with an in situ heating stage was employed for the real-time measurement. The Young’s modulus of the silicon monoxide thin film as well as the PDMS substrate was measured on the basis of the elasticity theory. Moreover, the effects of temperature variations on geometric parameters in the postbuckling state, such as wavelength and amplitude, were analyzed. It was proved that wavelength is relatively immune to thermal loads, while amplitude is much more sensitive.

1000537

NASA Image and Video Library

2010-04-13

NATHAN HORACE STRONG (AEROSPACE ENGINEER, ER31 PROPULSION TURBOMACHINERY DESIGN & DEVELOPMENT BRANCH) AND NATHAN COFFEE (EM10 MATERIALS TEST ENGINEER, JACOBS ESTS GROUP/JTI) ADJUST A UNIQUE MECHANICAL TEST SETUP THAT MEASURES STRAIN ON A SINGLE SAMPLE, USING TWO DIFFERENT TECHNIQUES AT THE SAME TIME. THE TEST FIXTURE HOLDS A SPECIMEN THAT REPRESENTS A LIQUID OXYGEN (LOX) BEARING FROM THE J2-X ENGINE. COFFEY, AT RIGHT, WORK IN A LAB IN BUILDING 4612 ON A BEARING TEST

Comparative Analysis of THOR-NT ATD vs. Hybrid III ATD in Laboratory Vertical Shock Testing

DTIC Science & Technology

2013-09-01

were taken both pretest and post - test for each test event (figure 5). Figure 5. Rigid fixture placed on the drop table with ATD seated: Hybrid III...6 3. Experimental Procedure 6 3.1 Test Setup...frames per second and with a Vision Research Phantom V9.1 (Wayne, NJ) high-speed video camera, sampling 1000 frames per second. 3. Experimental

High temperature tensile testing of ceramic composites

NASA Technical Reports Server (NTRS)

Gyekenyesi, John Z.; Hemann, John H.

1988-01-01

The various components of a high temperature tensile testing system are evaluated. The objective is the high temperature tensile testing of SiC fiber reinforced reaction bonded Si3N4 specimens at test temperatures up to 1650 C (3000 F). Testing is to be conducted in inert gases and air. Gripping fixtures, specimen configurations, furnaces, optical strain measuring systems, and temperature measurement techniques are reviewed. Advantages and disadvantages of the various techniques are also noted.

An investigation of hardwood plywood markets. Part 2. Fixture manufacturers

Treesearch

Craig L. Forbes; Larry G. Jahn; Philip A. Araman

2001-01-01

This is the second part of a two-part study investigating markets for hardwood plywood. Part 1 dealt with architectural woodworkers. North American fixture manufacturers were surveyed to better understand the structure and use of wood-based panels in the industry. A questionnaire was mailed to a sample of U.S. and Canadian fixture manufacturers. The sample consisted of...

Apparatus for correcting precision errors in slide straightness in machine tools

DOEpatents

Robinson, Samuel C.; Gerth, Howard L.

1981-01-01

The present invention is directed to a mechanism by which small deviations in slideway straightness and roll of a precision machining apparatus may be compensated for. The mechanism of the present invention comprises a fixture support disposed between the slideway carriage and the tool or workpiece fixture and provided with a hinge-like coupling between the carriage and the fixture support so as to allow for the minute and precise displacement of the fixture support in a direction normal to the direction of the slide path so as to readily compensate for slight deviations in the straightness and roll of the slide path.

Apparatus for correcting precision errors in slide straigntness in machine tools

DOEpatents

Robinson, S.C.; Gerth, H.L.

The present invention is directed to a mechanism by which small deviations in slideway straightness and roll of a precision machining apparatus may be compensated for. The mechanism of the present invention comprises a fixture support disposed between the slideway carriage and the tool or workpiece fixture and provided with a hinge-like coupling between the carriage and the fixture support so as to allow for the minute and precise displacement of the fixture support in a direction normal to the direction of the slide path soa as to readily compensate for slight deviations in the straightness and roll of the slide path.

Alveolar bone stress around implants with different abutment angulation: an FE-analysis of anterior maxilla.

PubMed

Sadrimanesh, Roozbeh; Siadat, Hakimeh; Sadr-Eshkevari, Pooyan; Monzavi, Abbas; Maurer, Peter; Rashad, Ashkan

2012-06-01

To comparatively assess the masticatory stress distribution in bone around implants placed in the anterior maxilla with three different labial inclinations. Three-dimensional finite element models were fabricated for three situations in anterior maxilla: (1) a fixture in contact with buccal cortical plate restored by straight abutment, (2) a fixture inclined at 15 degrees, and (3) 20 degrees labially restored with corresponding angled abutment. A palatal bite force of 146 N was applied to a point 3 mm below the incisal edge. Stress distribution around the bone-fixture interface was determined using ANSYS software. The maximum compressive stress, concentrated in the labial crestal cortical bone, was measured to be 62, 108, and 122 MPa for 0-, 15-, and 20-degree labially inclined fixtures, respectively. The maximum tensile stress, concentrated in the palatal crestal cortical bone, was measured to be 60, 108, and 120 MPa for 0-, 15-, and 20-degree labially inclined fixtures, respectively. While all compressive stress values were under the cortical yield strength of 169 MPa, tensile stress values partially surpassed the yield strength (104 MPa) especially when a 20-degree inclination was followed for fixture placement.

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

Gordon, Kelly L.; Foster, Rebecca; McGowan, Terry

This article for a building trade magazine describes a national design competition for energy efficient lighting sponsored by the U.S. Department of Energy, the American Lighting Association, and the Consortium for Energy Efficiency, with winners announced at ALA's Annual Conference May 14, 2004, in Tucson. The Lighting for Tomorrow competition was the first national lighting fixture design competition focusing on energy-efficient residential lighting. The competition invited fixture manufacturers and designers to come up with beautiful, functional lighting fixtures that also happen to be energy efficient. Fixtures were required to use a ''dedicated'' energy-efficient light source, such as a pin-based fluorescentmore » lamp that cannot be replaced with a screw-in incandescent bulb. Fixtures also had to meet a minimum energy efficiency level that eliminated use of incandescent and halogen lamps, leaving the door open only to fluorescent sources and LEDs. More than 150 paper designs were submitted in the first phase of the competition, in 2003. Of those, 24 finalists were invited to submit working prototypes in 2004, and the winners were announced in May. The Grand Prize of $10,000 went to American Fluorescent of Waukegan, Illinois, for its ''Salem'' chandelier. Some winning fixtures are already available through Lowe's Home Improvement Centers.« less

Orion is Taken From Ship & Put in Shipping Container

NASA Image and Video Library

2014-12-10

The Orion crew module is being lowered onto the crew module transportation fixture at the Mole Pier at Naval Base San Diego in California. The fixture has been secured on the back of a flatbed truck. Orion is being prepared for the overland trip back to NASA's Kennedy Space Center in Florida. Orion was recovered from the Pacific Ocean after completing a two-orbit, four-and-a-half hour mission Dec. 5 to test systems critical to crew safety, including the launch abort system, the heat shield and the parachute system. NASA, the U.S. Navy and Lockheed Martin coordinated efforts to recover Orion. The Ground Systems Development and Operations Program led the recovery, offload and pre-transportation efforts.

49 CFR 571.108 - Standard No. 108; Lamps, reflective devices, and associated equipment.

Code of Federal Regulations, 2012 CFR

2012-10-01

... which the headlamp is in the design open operating position. Headlamp concealment device means a device.... Headlamp test fixture means a device designed to support a headlamp or headlamp assembly in the test... (other than a standardized sealed beam headlamp designed to conform to paragraph S7.3 or a replaceable...

NASA-USRP Summer 2013 Internship Final Report

NASA Technical Reports Server (NTRS)

Gurganus, S. Christine

2013-01-01

Three major projects were undertaken during the Summer 2013 USRP Internship: (A) assisting the cTAPS group with component and pressure vessel system analyses and documentation, (B) designing a hoisting fixture for a solid rocket motor, (C) finding an alternative to removing the DOT rated gaseous nitrogen tank from the roof for hydrostatic testing. Hypergolic Material Assessments (HMAs) and pressure calculations were performed on components of pressure systems. Additionally, component information was logged in the Standard Parts Database to provide a location where system designers can find information regarding components, including their specifications and compatibility with fluids. A hoisting fixture was designed to hoist a solid rocket motor and meets the specifications related to stress and size. However, there are issues with the fixtures bolt head allotment, the bolt spacing, and the complexity of the part. Finally, calculations were performed on an expiring DOT rated gaseous nitrogen tank in an attempt to re-rate it per ASME standards. This was unsuccessful so other options are being explored for the tank. While much progress was made on all three projects, there is still work to be performed on each project to achieve the desired results.

Fracture resistance of different implant abutments supporting 
all-ceramic single crowns after aging.

PubMed

Stimmelmayr, Michael; Heiß, Philipp; Erdelt, Kurt; Schweiger, Josef; Beuer, Florian

To test the mechanical properties of three different restorative materials for implant abutments supporting all-ceramic single crowns. Thirty implants with butt-joint connections were distributed into three test groups: Group A with 10 one-piece zirconia abutments, Group U with 10 titanium abutments, and Group T with 10 titanium-zirconia hybrid abutments. Monolithic zirconia single crowns were cemented and artificially aged. The crowns were loaded at a 30-degree angle in a universal testing machine until fracture or bending. Additionally, after removal of the restorations, the implant-abutment interface of the fixtures was inspected using a scanning electron microscope (SEM). In Group A, the abutments failed on average at 336.78 N, in Group U at 1000.12 N, and in Group T at 1296.55 N. The mean values between Groups T and U (P = 0.009), and between Group A and Groups T and U (P < 0.001) were significantly different. The abutments in Group A failed early due to fractures of the internal parts and parts close to the implant neck. In Groups T and U, failures occurred due to bending of the implant neck. This experimental study proves that hybrid and titanium abutments have similar mechanical properties. One-piece abutments made of zirconia showed significantly lower fracture resistance.

Compact Fluorescent Plug-In Ballast-in-a-Socket

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

Rebecca Voelker

2001-12-21

The primary goal of this program was to develop a ballast system for plug-in CFLs (compact fluorescent lamps) that will directly replace standard metal shell, medium base incandescent lampholders (such as Levition No. 6098) for use with portable lamp fixtures, such as floor, table and desk lamps. A secondary goal was to identify a plug-in CFL that is optimized for use with this ballast. This Plug-in CFL Ballastin-a-Socket system will allow fixture manufacturers to easily manufacture CFL-based high-efficacy portable fixtures that provide residential and commercial consumers with attractive, cost-effective, and energy-efficient fixtures for use wherever portable incandescent fixtures are usedmore » today. The advantages of this proposed system over existing CFL solutions are that the fixtures can only be used with high-efficacy CFLs, and they will be more attractive and will have lower life-cycle costs than screw-in or adapter-based CFL retrofit solutions. These features should greatly increase the penetration of CFL's into the North American market. Our work has shown that using integrated circuits it is quite feasible to produce a lamp-fixture ballast of a size comparable to the current Edison-screw 3-way incandescent fixtures. As for price points for BIAS-based fixtures, end-users polled by the Lighting Research Institute at RPI indicated that they would pay as much as an additional $10 for a lamp containing such a ballast. The ballast has been optimized to run with a 26 W amalgam triple biax lamp in the base-down position, yet can accept non-amalgam versions of the lamp. With a few part alterations, the ballast can be produced to support 32 W lamps as well. The ballast uses GE's existing L-Comp[1] power topology in the circuit so that the integrated circuit design would be a design that could possibly be used by other CFL and EFL products with minor modifications. This gives added value by reducing cost and size of not only the BIAS, but also possibly other integral CFL and future dimmable integral and plug-in versions of the EFL products.« less

Study of mandible reconstruction using a fibula flap with application of additive manufacturing technology.

PubMed

Tsai, Ming-June; Wu, Ching-Tsai

2014-05-06

This study aimed to establish surgical guiding techniques for completing mandible lesion resection and reconstruction of the mandible defect area with fibula sections in one surgery by applying additive manufacturing technology, which can reduce the surgical duration and enhance the surgical accuracy and success rate. A computer assisted mandible reconstruction planning (CAMRP) program was used to calculate the optimal cutting length and number of fibula pieces and design the fixtures for mandible cutting, registration, and arrangement of the fibula segments. The mandible cutting and registering fixtures were then generated using an additive manufacturing system. The CAMRP calculated the optimal fibula cutting length and number of segments based on the location and length of the defective portion of the mandible. The mandible cutting jig was generated according to the boundary surface of the lesion resection on the mandible STL model. The fibular cutting fixture was based on the length of each segment, and the registered fixture was used to quickly arrange the fibula pieces into the shape of the defect area. In this study, the mandibular lesion was reconstructed using registered fibular sections in one step, and the method is very easy to perform. The application of additive manufacturing technology provided customized models and the cutting fixtures and registered fixtures, which can improve the efficiency of clinical application. This study showed that the cutting fixture helped to rapidly complete lesion resection and fibula cutting, and the registered fixture enabled arrangement of the fibula pieces and allowed completion of the mandible reconstruction in a timely manner. Our method can overcome the disadvantages of traditional surgery, which requires a long and different course of treatment and is liable to cause error. With the help of optimal cutting planning by the CAMRP and the 3D printed mandible resection jig and fibula cutting fixture, this all-in-one process of mandible reconstruction furnishes many benefits in this field by enhancing the accuracy of surgery, shortening the operation duration, reducing the surgical risk, and resulting in a better mandible appearance of the patients after surgery.

Study of mandible reconstruction using a fibula flap with application of additive manufacturing technology

PubMed Central

2014-01-01

Background This study aimed to establish surgical guiding techniques for completing mandible lesion resection and reconstruction of the mandible defect area with fibula sections in one surgery by applying additive manufacturing technology, which can reduce the surgical duration and enhance the surgical accuracy and success rate. Methods A computer assisted mandible reconstruction planning (CAMRP) program was used to calculate the optimal cutting length and number of fibula pieces and design the fixtures for mandible cutting, registration, and arrangement of the fibula segments. The mandible cutting and registering fixtures were then generated using an additive manufacturing system. The CAMRP calculated the optimal fibula cutting length and number of segments based on the location and length of the defective portion of the mandible. The mandible cutting jig was generated according to the boundary surface of the lesion resection on the mandible STL model. The fibular cutting fixture was based on the length of each segment, and the registered fixture was used to quickly arrange the fibula pieces into the shape of the defect area. In this study, the mandibular lesion was reconstructed using registered fibular sections in one step, and the method is very easy to perform. Results and conclusion The application of additive manufacturing technology provided customized models and the cutting fixtures and registered fixtures, which can improve the efficiency of clinical application. This study showed that the cutting fixture helped to rapidly complete lesion resection and fibula cutting, and the registered fixture enabled arrangement of the fibula pieces and allowed completion of the mandible reconstruction in a timely manner. Our method can overcome the disadvantages of traditional surgery, which requires a long and different course of treatment and is liable to cause error. With the help of optimal cutting planning by the CAMRP and the 3D printed mandible resection jig and fibula cutting fixture, this all-in-one process of mandible reconstruction furnishes many benefits in this field by enhancing the accuracy of surgery, shortening the operation duration, reducing the surgical risk, and resulting in a better mandible appearance of the patients after surgery. PMID:24885749