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Sample records for ngnp tensile test

  1. NGNP Graphite Testing and Qualification Specimen Selection Strategy

    SciTech Connect

    Robert Bratton

    2005-05-01

    The available grades of graphite for the NGNP are reviewed. A selection matrix is presented outlining the available grades for the NGNP graphite irradiation program based upon input from potential NGNP vendors, graphite manufactures, and graphite experts.

  2. NGNP Component Test Capability Design Code of Record

    SciTech Connect

    S.L. Austad; D.S. Ferguson; L.E. Guillen; C.W. McKnight; P.J. Petersen

    2009-09-01

    The Next Generation Nuclear Plant Project is conducting a trade study to select a preferred approach for establishing a capability whereby NGNP technology development testing—through large-scale, integrated tests—can be performed for critical HTGR structures, systems, and components (SSCs). The mission of this capability includes enabling the validation of interfaces, interactions, and performance for critical systems and components prior to installation in the NGNP prototype.

  3. Tensile testing apparatus

    NASA Technical Reports Server (NTRS)

    Blackburn, L. B.; Ellingsworth, J. R. (Inventor)

    1985-01-01

    An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip and flat surface are provided in each sampling engaging platens to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

  4. Tensile testing apparatus

    NASA Astrophysics Data System (ADS)

    Blackburn, L. B.; Ellingsworth, J. R.

    1985-08-01

    An improved mechanical extensometer is described for use with a constant load creep test machine. The dead weight of the extensometer is counterbalanced by two pairs of weights connected through a pulley system and to rod extension and leading into the furnace where the test sample is undergoing elevated temperature (above 500 F.) tensile testing. Novel gripper surfaces, conical tip and flat surface are provided in each sampling engaging platens to reduce the grip pressure normally required for attachment of the extensometer to the specimen and reduce initial specimen bending normally associated with foil-gage metal testing.

  5. Improved Tensile Test for Ceramics

    NASA Technical Reports Server (NTRS)

    Osiecki, R. A.

    1982-01-01

    For almost-nondestructive tensile testing of ceramics, steel rod is bonded to sample of ceramic. Assembly is then pulled apart in conventional tensile-test machine. Test destroys only shallow surface layer which can be machined away making specimen ready for other uses. Method should be useful as manufacturing inspection procedure for low-strength brittle materials.

  6. Tensile Testing: A Simple Introduction

    ERIC Educational Resources Information Center

    Carr, Martin

    2006-01-01

    Tensile testing may be used to decide, say, which steel to use in various constructions. Analogous testing can be done simply in the classroom using plasticine and helps to introduce pupils to the various properties studied in materials science.

  7. Tensile Test For Arboform Samples

    NASA Astrophysics Data System (ADS)

    Plavanescu (Mazurchevici), Simona; Quadrini, Fabrizio; Nedelcu, Dumitru

    2015-07-01

    Petroleum-based plastic materials constitute a major environmental problem due to their low biodegradability and accumulation in various environments. Therefore, searching for novel biodegradable plastics is received particular attention. Our studied material, "Liquid wood" produced from lignin, natural fibres and natural additives, is completely biodegradable in natural environment, in normal conditions. This paper presents the behaviour of Arboform and Arboform reinforced with Aramidic Fibers tensile test analysis. Experimental data show that the tensile strength reached an average value of 15.8 MPa, the modulus of elasticity after tests is 3513.3MPA for Arboform and for the reinforcement the tensile strength is 23.625MPa, the modulus of elasticity after tests is 3411.5MPA, the materials present a brittle behaviour. The high mechanical properties of newly developed material, better than of other ordinary plastics, recommend it as a potential environment-friendly substituent for synthetic plastics, which are present in all fields of activity.

  8. Elongation Transducer For Tensile Tests

    NASA Technical Reports Server (NTRS)

    Roberts, Paul W.; Stokes, Thomas R.

    1994-01-01

    Extensometer transducer measures elongation of tensile-test specimen with negligible distortion of test results. Used in stress-versus-strain tests of small specimens of composite materials. Clamping stress distributed more evenly. Specimen clamped gently between jaw and facing surface of housing. Friction force of load points on conical tips onto specimen depends on compression of spring, adjusted by turning cover on housing. Limp, light nylon-insulated electrical leads impose minimal extraneous loads on measuring elements.

  9. Manual for LDEF tensile tests

    NASA Technical Reports Server (NTRS)

    Witte, W. G., Jr.

    1985-01-01

    One of the experiments aboard the NASA Long Duration Exposure Facility (LDEF) consists of a tray of approximately one hundred tensile specimens of several candidate space structure composite materials. During the LDEF flight the materials will be subjected to the space environment and to possible contamination during launch and recovery. Tensile tests of representative samples were made before the LDEF flight to obtain baseline data. Similar tests will be made on control specimens stored on earth for the length of the LDEF flight and on recovered flight specimens. This manual codifies the details of testing, data acquisition, and handling used in obtaining the baseline data so that the same procedures and equipment will be used on the subsequent tests.

  10. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2006-01-10

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  11. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-08-21

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  12. Micro-tensile testing system

    DOEpatents

    Wenski, Edward G.

    2007-07-17

    A micro-tensile testing system providing a stand-alone test platform for testing and reporting physical or engineering properties of test samples of materials having thicknesses of approximately between 0.002 inch and 0.030 inch, including, for example, LiGA engineered materials. The testing system is able to perform a variety of static, dynamic, and cyclic tests. The testing system includes a rigid frame and adjustable gripping supports to minimize measurement errors due to deflection or bending under load; serrated grips for securing the extremely small test sample; high-speed laser scan micrometers for obtaining accurate results; and test software for controlling the testing procedure and reporting results.

  13. 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.

  14. Status of the Combined Third and Fourth NGNP Fuel Irradiations In the Advanced Test Reactor

    SciTech Connect

    S. Blaine Grover; David A. Petti; Michael E. Davenport

    2013-07-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program is irradiating up to seven low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The experiments will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of several independent capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2) started irradiation in June 2010 and is currently scheduled to be completed in September 2013. The third and fourth experiments have been combined into a single experiment designated (AGR-3/4), which started its irradiation in December 2011 and is currently scheduled to be completed in April 2014. Since the purpose of this combined experiment is to provide data on fission product migration and retention in the NGNP reactor, the design of this experiment is

  15. NGNP Research and Development Status

    SciTech Connect

    David A. Petti

    2010-08-01

    At the inception of the Next Generation Nuclear Plant (NGNP) project, experts from the Department of Energy (DOE) national laboratories, gas reactor vendors, and universities collaborated to establish technology research and development (R&D) roadmaps. These roadmaps outlined the testing and computational development activities needed to qualify the materials and validate the modeling and simulation tools to be used in the design and safe operation of the NGNP, a helium-cooled, high temperature gas reactor (HTGR).

  16. In Situ Radiography During Tensile Tests

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Bhatt, Ramakrishna T.

    1994-01-01

    Laboratory system for testing specimens of metal-, ceramic-, and intermetallic-matrix composite materials incorporates both electromechanical tensile-testing subsystem and either of two imaging subsystems that take x-ray photographs of specimens before, during, and after tensile tests. Used to test specimens of reaction-bonded silicon nitride reinforced with silicon carbide fibers (SiC/RBSN) considered for high-temperature service in advanced aircraft turbine engines. Provides data on effects of preexisting flaws (e.g., high-density impurities and local variations of density) on fracture behavior. Accumulated internal damage monitored during loading. X-ray source illuminates specimen in load frame while specimen is pulled. X-ray images on film correlated with stress-vs.-strain data from tensile test.

  17. Status of the NGNP Fuel Experiment AGR-2 Irradiated in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover

    2012-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2), which utilized the same experiment design as well as control and monitoring systems as AGR-1, started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The design of this experiment and support systems will be briefly discussed, followed by the progress and status of the experiment to date.

  18. Status of the NGNP fuel experiment AGR-2 irradiated in the advanced test reactor

    SciTech Connect

    S. Blaine Grover; David A. Petti

    2014-05-01

    The United States Department of Energy's Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also undergo on-line fission product monitoring to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2), which utilized the same experiment design as well as control and monitoring systems as AGR-1, started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The design of this experiment and sup

  19. Pressure reversal study through tensile tests

    SciTech Connect

    Swinson, W.F.; Battiste, R.L.; Wright, A.L.; Yahr, G.T.; Robertson, J.P.

    1997-12-31

    This paper is a summary of the results from a study of the variables related to pressure reversal and was sponsored by the US Department of Transportation, Office of Pipeline Safety. The circumferential pipe stress, which is the most significant variable in pressure reversal, was examined by using tensile specimens and then relating the results to pressurized pipe. A model is proposed that gives some insight into how pressure reversal can be minimized when a section of pipe is being hydrotested. Twenty tensile specimens from X-42 electric resistance welded (ERW) pipe and twenty specimens from X-52 ERW pipe were tested. Each specimen had a machined flaw. The flaw regions were monitored using strain gages and photoelasticity. These tensile tests represent the first phase of a research effort to examine and understand the variables related to pressure reversal. The second phase of this effort will be with pipe specimens and presently is in progress.

  20. Approaches for Tensile Testing of Braided Composites

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Salem, Jonathan A.; Bail, Justin L.; Kohlman, Lee W.; Binienda, Wieslaw K.; Martin, Richard E.

    2011-01-01

    For angleply composites, lamina tension and compression strengths are commonly determined by applying classical lamination theory to test data obtained from testing of angleply composite specimens. For textile composites such as 2D triaxial braids, analysis is more complex and standard test methods do not always yield reliable strength measurements. This paper describes recent research focused on development of more reliable tensile test methods for braided composites and presents preliminary data for various approaches. The materials investigated in this work have 0deg+/-60 2D triaxial braid architecture with nearly equal fiber volume fraction in each of the three fiber directions. Flat composite panels are fabricated by resin transfer molding (RTM) using six layers of the braided preform aligned along the 0deg fiber direction. Various epoxy resins are used as matrix materials. Single layer panels are also fabricated in order to examine local variations in deformation related to the braid architecture. Specimens are cut from these panels in the shape of standard straight-sided coupons, an alternative bowtie geometry, and an alternative notched geometry. Axial tensile properties are measured using specimens loaded along the 0deg fiber direction. Transverse tensile properties are measured using specimens loaded perpendicular to the 0deg fibers. Composite tubes are also fabricated by RTM. These tubes are tested by internal pressurization using a soft rubbery material sealed between the inside diameter of the tube and the load fixtures. The ends of the tube are unconstrained, so the primary load is in the hoop direction. Tubes are fabricated with the 0deg fibers aligned along the tube axis by overbraiding the preform on a mandrel. Since the loading is in the hoop direction, testing of the overbraided tube provides a measure of transverse tensile strength. Previous work has indicated that straight-sided coupons yield a transverse tensile strength that is much lower

  1. Status of the NGNP graphite creep experiments AGC-1 and AGC-2 irradiated in the advanced test reactor

    SciTech Connect

    S. Blaine Grover

    2014-05-01

    The United States Department of Energy's Next Generation Nuclear Plant (NGNP) Program will be irradiating six nuclear graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the next generation nuclear plant (NGNP) very high temperature gas reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain six peripheral stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six peripheral stacks will have three different compressive loads applied to the top half of three diametrically opposite pairs of specimen stacks, while a seventh stack will not have a compressive load. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during irradiation of the experiment.

  2. Status of the NGNP Graphite Creep Experiments AGC-1 and AGC-2 Irradiated in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover

    2012-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Program will be irradiating six nuclear graphite creep experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The graphite experiments will be irradiated over the next six to eight years to support development of a graphite irradiation performance data base on the new nuclear grade graphites now available for use in high temperature gas reactors. The goals of the irradiation experiments are to obtain irradiation performance data, including irradiation creep, at different temperatures and loading conditions to support design of the Next Generation Nuclear Plant (NGNP) Very High Temperature Gas Reactor, as well as other future gas reactors. The experiments will each consist of a single capsule that will contain six peripheral stacks of graphite specimens, with half of the graphite specimens in each stack under a compressive load, while the other half of the specimens will not be subjected to a compressive load during irradiation. The six peripheral stacks will have different compressive loads applied to the top half of each pair of specimen stacks, while a seventh stack will not have a compressive load. The specimens will be irradiated in an inert sweep gas atmosphere with on-line temperature and compressive load monitoring and control. There will also be sampling the sweep gas effluent to determine if any oxidation or off-gassing of the specimens occurs during irradiation of the experiment. The first experiment, AGC-1, started its irradiation in September 2009, and the irradiation was completed in January 2011. The second experiment, AGC-2, started its irradiation in April 2011 and completed its irradiation in May 2012. This paper will briefly discuss the design of the experiment and control systems, and then present the irradiation results for each experiment to date.

  3. High-speed tensile test instrument

    NASA Astrophysics Data System (ADS)

    Mott, P. H.; Twigg, J. N.; Roland, D. F.; Schrader, H. S.; Pathak, J. A.; Roland, C. M.

    2007-04-01

    A novel high-speed tensile test instrument is described, capable of measuring the mechanical response of elastomers at strain rates ranging from 10 to 1600 s-1 for strains through failure. The device employs a drop weight that engages levers to stretch a sample on a horizontal track. To improve dynamic equilibrium, a common problem in high speed testing, equal and opposite loading was applied to each end of the sample. Demonstrative results are reported for two elastomers at strain rates to 588 s-1 with maximum strains of 4.3. At the higher strain rates, there is a substantial inertial contribution to the measured force, an effect unaccounted for in prior works using the drop weight technique. The strain rates were essentially constant over most of the strain range and fill a three-decade gap in the data from existing methods.

  4. Static tensile and tensile creep testing of four boron nitride coated ceramic fibers at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Coguill, Scott L.; Adams, Donald F.; Zimmerman, Richard S.

    1989-01-01

    Six types of uncoated ceramic fibers were static tensile and tensile creep tested at various elevated temperatures. Three types of boron nitride coated fibers were also tested. Room temperature static tensile tests were initially performed on all fibers, at gage lengths of 1, 2, and 4 inches, to determine the magnitude of end effects from the gripping system used. Tests at one elevated temperature, at gage lengths of 8 and 10 inches, were also conducted, to determine end effects at elevated temperatures. Fiber cross sectional shapes and areas were determined using scanning electron microscopy. Creep testing was typically performed for 4 hours, in an air atmosphere.

  5. Design and Status of the NGNP Fuel Experiment AGR-3/4 Irradiated in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover

    2012-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and was completed in November 2009. The second experiment (AGR-2) started irradiation in June 2010 and is currently scheduled to be completed in April 2013. The third and fourth experiments have been combined into a single experiment designated AGR-3/4, which started its irradiation in December 2011 and is currently scheduled to be completed in November 2013. Since the purpose of this experiment is to provide data on fission product migration and retention in the NGNP reactor, the design of this experiment is

  6. Graphite/Polyimide Tabs For High-Temperature Tensile Tests

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Papadopoulos, Demetrios S.

    1993-01-01

    Delamination from ceramic composite specimens prevented. Tabs made from composite of graphite and PMR-15 polyimide enable high-temperature tensile testing of flat coupons of ceramic-matrix composites. Also used in high-temperature tensile testing of flat coupons of ceramics, metals, and metal-matrix composites.

  7. Apparatus facilitates high-temperature tensile testing in vacuum

    NASA Technical Reports Server (NTRS)

    Sikora, P. F.

    1964-01-01

    An apparutus for heating refractory materials to high temperatures during tensile testing includes a water-cooled stainless steel vacuum chamber. This contains a resistance heater consisting of a slit tube of tantalum or tungsten to enclose the tensile test rod.

  8. Polystyrene cryostat facilitates testing tensile specimens under liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Shogan, R. P.; Skalka, R. J.

    1967-01-01

    Lightweight cryostat made of expanded polystyrene reduces eccentricity in a tensile system being tested under liquid nitrogen. The cryostat is attached directly to the tensile system by a special seal, reducing misalignment effects due to cryostat weight, and facilitates viewing and loading of the specimens.

  9. Completion of the first NGNP Advanced Gas Reactor Fuel Irradiation Experiment, AGR-1, in the Advanced Test Reactor

    SciTech Connect

    Blaine Grover; John Maki; David Petti

    2010-10-01

    The United States Department of Energy’s Next Generation Nuclear Plant (NGNP) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The ATR has a long history of irradiation testing in support of reactor development and the INL has been designated as the United States Department of Energy’s lead laboratory for nuclear energy development. The ATR is one of the world’s premiere test reactors for performing long term, high flux, and/or large volume irradiation test programs. These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States, and will be irradiated over the next several years to demonstrate and qualify new TRISO coated particle fuel for use in high temperature gas reactors. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which will each consist of at least six separate capsules, will be irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gas will also have on-line fission product monitoring on its effluent to track performance of the fuel in each individual capsule during irradiation. The first experiment (designated AGR-1) started irradiation in December 2006 and completed a very successful irradiation in early November 2009. The design of AGR-1 test train and support systems used to monitor and control the experiment during

  10. Elevated Temperature Tensile Tests on DU–10Mo Rolled Foils

    SciTech Connect

    Schulthess, Jason

    2014-09-01

    Tensile mechanical properties for uranium-10 wt.% molybdenum (U–10Mo) foils are required to support modeling and qualification of new monolithic fuel plate designs. It is expected that depleted uranium-10 wt% Mo (DU–10Mo) mechanical behavior is representative of the low enriched U–10Mo to be used in the actual fuel plates, therefore DU-10Mo was studied to simplify material processing, handling, and testing requirements. In this report, tensile testing of DU-10Mo fuel foils prepared using four different thermomechanical processing treatments were conducted to assess the impact of foil fabrication history on resultant tensile properties.

  11. Improved Flat Specimens For Tensile And Fatigue Testing Of Composites

    NASA Technical Reports Server (NTRS)

    Worthem, Dennis W.

    1994-01-01

    Improved shape proposed for flat, reduced-gauge-section specimens for tensile and fatigue testing of advanced composite materials at ambient and high temperatures. Typical specimen consists of flat bar 15.2 centimeters long, 1.27 centimeters wide, and 0.318 centimeters thick, with full-width tab regions at ends, 3.81-centimeters-long gauge section of reduced width in middle, and two transition regions where width tapers between tab and gauge widths along 6.35-centimeters-radius circular arc tangent to edge of gauge section. Specimen gripped by squeezing between tabs in tab regions, and tensile test load applied via tab grips. Configuration reduces undesired concentrations of stresses in transition and tab regions, forcing tensile failure to occur in gauge section and ensuring more-consistent results in tensile tests.

  12. Static tensile and tensile creep testing of five ceramic fibers at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Zimmerman, Richard S.; Adams, Donald F.

    1989-01-01

    Static tensile and tensile creep testing of five ceramic fibers at elevated temperature was performed. J.P. Stevens, Co., Astroquartz 9288 glass fiber; Nippon Carbon, Ltd., (Dow Corning) nicalon NLM-102 silicon carbide fiber; and 3M Company Nextel 312, 380, and 480 alumina/silica/boria fibers were supplied in unsized tows. Single fibers were separated from the tows and tested in static tension and tensile creep. Elevated test temperatures ranged from 400 C to 1300 C and varied for each fiber. Room temperature static tension was also performed. Computer software was written to reduce all single fiber test data into engineering constants using ASTM Standard Test Method D3379-75 as a reference. A high temperature furnace was designed and built to perform the single fiber elevated temperature testing up to 1300 C. A computerized single fiber creep apparatus was designed and constructed to perform four fiber creep tests simultaneously at temperatures up to 1300 C. Computer software was written to acquire and reduce all creep data.

  13. Static tensile and tensile creep testing of five ceramic fibers at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Zimmerman, Richard S.; Adams, Donald F.

    1988-01-01

    Static tensile and tensile creep testing of five ceramic fibers at elevated temperature was performed. J.P. Stevens, Co., Astroquartz 9288 glass fiber, Nippon Carbon, Ltd., (Dow Corning) Nicalon NLM-102 silicon carbide fiber, and 3M Company Nextel 312, 380, and 480 alumina/silica/boria fibers were supplied in unsized tows. Single fibers were separated from the tows and tested in static tension and tensile creep. Elevated test temperatures ranged from 400 to 1300 C and varied for each fiber. Room temperature static tension was also performed. Computer software was written to reduce all single fiber test data into engineering constants using ASTM Standard Test Method D3379-75 as a reference. A high temperature furnace was designed and built to perform the single fiber elevated temperature testing up to 1300 C. A computerized single fiber creep apparatus was designed and constructed to perform four fiber creep tests simultaneously at temperatures up to 1300 C. Computer software was written to acquire and reduce all creep data.

  14. Demonstration of concurrent tensile testing and magnetic resonance elastography.

    PubMed

    Brinker, Spencer; Klatt, Dieter

    2016-10-01

    Magnetic Resonance Elastography (MRE) is a technique used to measure the mechanical properties of soft tissues and has already shown its diagnostic potential for pathologies involving fibrogenesis and neurodegeneration. Experimental investigation of loading during MRE is fairly unexplored and may help to better understand changing mechanical properties in relation to organ function. Tensile testing is a common technique for examining mechanical properties of materials and is used as the simultaneous comparison method with MRE in this study. 3D MRE data was acquired during quasistatic uniaxial tensile loading of an Ecoflex 0010 cylindrical specimen. Individual MRE scans at 1.5, 2.0, and 2.5kHz where performed on engineering strain increments of 20% from 0% to 140% while tensile reaction force was recorded using a load cell attached to an adjustable elongation slide. Tensile stress-strain relation resembled the Fung hyperelastic strain energy model. We observe that the MRE shear storage modulus is related to the state of tensile deformation. This study demonstrates the feasibility of simultaneous tensile testing during MRE and the new design can potentially be used for MRE calibration using pre-tension. PMID:27429072

  15. Updated NGNP Fuel Acquisition Strategy

    SciTech Connect

    David Petti; Tim Abram; Richard Hobbins; Jim Kendall

    2010-12-01

    A Next Generation Nuclear Plant (NGNP) fuel acquisition strategy was first established in 2007. In that report, a detailed technical assessment of potential fuel vendors for the first core of NGNP was conducted by an independent group of international experts based on input from the three major reactor vendor teams. Part of the assessment included an evaluation of the credibility of each option, along with a cost and schedule to implement each strategy compared with the schedule and throughput needs of the NGNP project. While credible options were identified based on the conditions in place at the time, many changes in the assumptions underlying the strategy and in externalities that have occurred in the interim requiring that the options be re-evaluated. This document presents an update to that strategy based on current capabilities for fuel fabrication as well as fuel performance and qualification testing worldwide. In light of the recent Pebble Bed Modular Reactor (PBMR) project closure, the Advanced Gas Reactor (AGR) fuel development and qualification program needs to support both pebble and prismatic options under the NGNP project. A number of assumptions were established that formed a context for the evaluation. Of these, the most important are: • Based on logistics associated with the on-going engineering design activities, vendor teams would start preliminary design in October 2012 and complete in May 2014. A decision on reactor type will be made following preliminary design, with the decision process assumed to be completed in January 2015. Thus, no fuel decision (pebble or prismatic) will be made in the near term. • Activities necessary for both pebble and prismatic fuel qualification will be conducted in parallel until a fuel form selection is made. As such, process development, fuel fabrication, irradiation, and testing for pebble and prismatic options should not negatively influence each other during the period prior to a decision on reactor type

  16. Method and apparatus for tensile testing of metal foil

    NASA Technical Reports Server (NTRS)

    Wade, O. W. (Inventor)

    1976-01-01

    A method for obtaining accurate and reproducible results in the tensile testing of metal foils in tensile testing machines is described. Before the test specimen are placed in the machine, foil side edges are worked until they are parallel and flaw free. The specimen are also aligned between and secured to grip end members. An aligning apparatus employed in the method is comprised of an alignment box with a longitudinal bottom wall and two upright side walls, first and second removable grip end members at each end of the box, and a means for securing the grip end members within the box.

  17. Polymer deformation gage measures thickness change in tensile tests

    NASA Technical Reports Server (NTRS)

    Broyles, H. F.; Broyles, H. H.

    1966-01-01

    Lightweight deformation gage attached to a polymer specimen determines the thickness changes undergone by the specimen during the testing of its tensile and elongation properties. Mechanical noise from outside sources is dampened when the assembly is hung on a light rubber band.

  18. Tensile testing grips are easily assembled under liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Skalka, R. J.; Vandergrift, E. F.

    1967-01-01

    Split-screw grips for tensile testing provide uniform loading on the specimen shoulders. Holes in the heads enable the screws and specimen to be threaded as an assembly into a grip body, closely controlled guides and seats afford positive seating, and precision machining of mating surfaces minimizes misalignment effects.

  19. Tensile testing grips ensure uniform loading of bimetal tubing specimens

    NASA Technical Reports Server (NTRS)

    Driscol, S. D.; Hunt, V.

    1968-01-01

    Tensile testing grip uniformly distributes stresses to the internal and external tube of bimetal tubing specimens. The grip is comprised of a slotted external tube grip, a slotted internal tube grip, a machine bolt and nut, an internal grip expansion cone, and an external grip compression nut.

  20. Apparatus for tensile testing plate-type ceramic specimens

    DOEpatents

    Liu, K.C.

    1993-08-24

    Apparatus is described for gripping a plate-type tensile specimen having generally T-shaped end regions in a dynamic tension fatigue testing apparatus comprising an annular housing having an open-ended elongated cavity therein, a plurality of hydraulic piston means supported by the housing in a spaced array about the cavity, and a specimen-supporting plate means overlying the piston means at one end of the elongated cavity and displaceable by said piston means in a longitudinal direction with respect to the longitudinal axis of the cavity, said apparatus for gripping a flat plate-type tensile specimen comprising: a pair of elongated pull rods each having oppositely disposed first and second end regions; a pair of mounting means carried by said plate means with each mounting means for pivotally attaching the first end region of each of said pull rods in a central region of said plate means for supporting said pair of elongated pull rods in a side-by-side relationship along a common longitudinal centerline within said cavity; recess means in the second end region of each of said pull rods in adjacently disposed surface regions thereof with said recess means facing one another and each adapted to receive one side of one of the generally T-shaped end regions of the plate-type tensile specimen; and load-bearing means positionable in each of said recess means and adapted to bear against a shoulder on each side of the generally T-shaped end region of the plate-type tensile specimen when a tensile loading is applied thereon.

  1. Optical strain measuring techniques for high temperature tensile testing

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Hemann, John H.

    1987-01-01

    A number of optical techniques used for the analysis of in-plane displacements or strains are reviewed. The application would be for the high temperature, approximately 1430 C (2600 F), tensile testing of ceramic composites in an oxidizing atmosphere. General descriptions of the various techniques and specifics such as gauge lengths and sensitivities are noted. Also, possible problems with the use of each method in the given application are discussed.

  2. On the off-axis tensile test for unidirectional composites

    NASA Technical Reports Server (NTRS)

    Nemeth, M. P.; Herakovich, C. T.; Post, D.

    1982-01-01

    The off axis tensile test was examined experimentally to obtain actual displacement fields over the surface of graphite polyimide coupon specimens. The experimental results were compared with approximate analytical solutions and generated finite element results. An optical method of high sensitivity moire interferometry was used to determine the actual displacements to high precision. The approximate analytical solution and the finite element results compare very favorably with the measured centerline displacements in the test section, and the finite element displacement fields provide excellent agreement with the moire displacements throughout the specimen. A 15 degree fiber orientation and coupon aspect ratios of 5 and 15 are presented.

  3. Tensile adhesion testing of thermal spray coatings on flat substrates

    SciTech Connect

    Leigh, S.H.; Berndt, C.C.; Wu, C.L.; Nakamura, T.

    1994-12-31

    The standard tensile adhesion test (TAT), ASTM C633, has been modified to perform multiple tests on flat and wide substrates. The TAT geometry which specifies a 25.4 mm (1 in.) diameter cylindrical substrate has been employed as the pull-off bar. Two renditions of this test were implemented and the Weibull moduli and characteristics tresses for both test methods obtained. The modified TAT, termed as the single bar (SB) method, yields a higher Weibull modulus and characteristic strength than the other method which is termed as the double bar (DB) method. It is expected that the different test results between the two methods arise from different stress distributions near the interface of the coating and substrate. Finite element analysis was used to obtain the stress distribution near the interface of the coating and substrate, and the relationship between the adhesion strength of the SB and DB methods were derived.

  4. Compressive tensile and shear testing of melt-foamed aluminium

    SciTech Connect

    Von Hagen, H.; Bleck, W.

    1998-12-31

    For construction purposes it is utterly important to get detailed information on the possible influence of the foam thickness on the mechanical properties and on the deformation behavior of metallic foams. The effect of compressive, tensile and shear loads on aluminium foam samples has been examined with the testing methods for sandwich material as described in German and ASTM-standards. The aim is to provide more data on these mechanical properties varying the sample density and thickness. Regarding the results the most reliable material parameters as well as steps towards a relationship between the different strength parameters can be obtained.

  5. Evaluation of ultimate tensile strength using Miniature Disk Bend Test

    NASA Astrophysics Data System (ADS)

    Kumar, Kundan; Pooleery, Arun; Madhusoodanan, K.; Singh, R. N.; Chakravartty, J. K.; Shriwastaw, R. S.; Dutta, B. K.; Sinha, R. K.

    2015-06-01

    Correlations for evaluation of Ultimate Tensile Strength (UTS) using Miniature Disk Bend Test (MDBT) or Small Punch Test (SPT) has been an open issue since the development of the techniques. The larger plastic strains, in tri-axial state of stress during SPT, make the translation to the equivalent uniaxial parameter less certain. Correlations based on Pmax of load-displacement curve are also in disagreement as the point corresponding to Pmax does not represent a necking situation as in case of UTS, in a uniaxial tensile test. In present work, an attempt has been made for locating necking zone, which appears prior to Pmax, through experiments and FEM analyses. Experimental results on disk specimens from 20MnMoNi55, CrMoV ferritic steel and SS304LN materials along with FEM analyses found that load corresponding to 0.48 mm displacement is to be very close to the necking zone, and gives best fit for a UTS correlation.

  6. Tensile testing of ultra-thin films on water surface

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Han; Nizami, Adeel; Hwangbo, Yun; Jang, Bongkyun; Lee, Hak-Joo; Woo, Chang-Su; Hyun, Seungmin; Kim, Taek-Soo

    2013-10-01

    The surface of water provides an excellent environment for gliding movement, in both nature and modern technology, from surface living animals such as the water strider, to Langmuir-Blodgett films. The high surface tension of water keeps the contacting objects afloat, and its low viscosity enables almost frictionless sliding on the surface. Here we utilize the water surface as a nearly ideal underlying support for free-standing ultra-thin films and develop a novel tensile testing method for the precise measurement of mechanical properties of the films. In this method, namely, the pseudo free-standing tensile test, all specimen preparation and testing procedures are performed on the water surface, resulting in easy handling and almost frictionless sliding without specimen damage or substrate effects. We further utilize van der Waals adhesion for the damage-free gripping of an ultra-thin film specimen. Our approach can potentially be used to explore the mechanical properties of emerging two-dimensional materials.

  7. Method and device for tensile testing of cable bundles

    SciTech Connect

    Robertson, Lawrence M; Ardelean, Emil V; Goodding, James C; Babuska, Vit

    2012-10-16

    A standard tensile test device is improved to accurately measure the mechanical properties of stranded cables, ropes, and other composite structures wherein a witness is attached to the top and bottom mounting blocks holding the cable under test. The witness is comprised of two parts: a top and a bottom rod of similar diameter with the bottom rod having a smaller diameter stem on its upper end and the top rod having a hollow opening in its lower end into which the stem fits forming a witness joint. A small gap is present between the top rod and the larger diameter portion of the bottom rod. A standard extensometer is attached to the top and bottom rods of the witness spanning this small witness gap. When a force is applied to separate the mounting blocks, the gap in the witness expands the same length that the entire test specimen is stretched.

  8. ROLE OF SCALE FACTOR DURING TENSILE TESTING OF SMALL SPECIMENS

    SciTech Connect

    Gussev, Maxim N; Busby, Jeremy T; Field, Kevin G; Sokolov, Mikhail A; Gray, Mr. Sean

    2014-01-01

    The influence of scale factor (tensile specimen geometry and dimensions) on mechanical test results was investigated for different widely used types of small specimens (SS-1, SS-2, SS-3, and SS-J3) and a set of materials. It was found that the effect of scale factor on the accurate determination of yield stress, ultimate tensile stress, and uniform elongation values was weak; however, clear systematic differences were observed and should be accounted for during interpretation of results. In contrast, total elongation values were strongly sensitive to variations in specimen geometry. Modern experimental methods like digital image correlation allow the impact of scale factor to be reduced. Using these techniques, it was shown that true stress true strain curves describing strain-hardening behavior were very close for different specimen types. The limits of miniaturization are discussed, and an ultra-miniature specimen concept was suggested and evaluated. This type of specimen, as expected, may be suitable for SEM and TEM in situ testing.

  9. In situ tensile and creep testing of lithiated silicon nanowires

    SciTech Connect

    Boles, Steven T.; Kraft, Oliver; Thompson, Carl V.; Mönig, Reiner

    2013-12-23

    We present experimental results for uniaxial tensile and creep testing of fully lithiated silicon nanowires. A reduction in the elastic modulus is observed when silicon nanowires are alloyed with lithium and plastic deformation becomes possible when the wires are saturated with lithium. Creep testing was performed at fixed force levels above and below the tensile strength of the material. A linear dependence of the strain-rate on the applied stress was evident below the yield stress of the alloy, indicating viscous deformation behavior. The observed inverse exponential relationship between wire radius and strain rate below the yield stress indicates that material transport was controlled by diffusion. At stress levels approaching the yield strength of fully lithiated silicon, power-law creep appears to govern the strain-rate dependence on stress. These results have direct implications on the cycling conditions, rate-capabilities, and charge capacity of silicon and should prove useful for the design and construction of future silicon-based electrodes.

  10. Effects of strain rate, test temperature and test environment on tensile properties of vandium alloys

    SciTech Connect

    Gubbi, A.N.; Rowcliffe, A.F.; Eatherly, W.S.; Gibson, L.T.

    1996-10-01

    Tensile testing was carried out on SS-3 tensile specimens punched from 0.762-mm-thick sheets of the large heat of V-4Cr-4Ti and small heats of V-3Cr-3Ti and V-6Cr-6Ti. The tensile specimens were annealed at 1000{degrees} for 2 h to obtain a fully recrystallized, fine grain microstructure with a grain size in the range of 10-19 {mu}m. Room temperature tests at strain rates ranging from 10{sup {minus}3} to 5 x 10{sup {minus}1}/s were carried out in air; elevated temperature testing up to 700{degrees}C was conducted in a vacuum better than 1 x 10{sup {minus}5} torr (<10{sup {minus}3} Pa). To study the effect of atomic hydrogen on ductility, tensile tests were conducted at room temperature in an ultra high vacuum chamber (UHV) with a hydrogen leak system.

  11. A microdynamic version of the tensile test machine

    NASA Technical Reports Server (NTRS)

    Glaser, R. J.

    1991-01-01

    Very large space structures require structural reactions to control forces associated with nanometer-level displacements; JPL has accordingly built a tensile test machine capable of mN-level force measurements and nm-level displacement measurements, with a view to the study of structural linear joining technology at the lower limit of its resolution. The tester is composed of a moving table that is supported by six flexured legs and a test specimen cantilevered off the table to ground. Three vertical legs contain piezoactuators allowing changes in length up to 200 microns while generating axial load and bending moments. Displacements between ground and table are measured by means of three laser-interferometric channels.

  12. Tensile adhesion testing methodology for thermally sprayed coatings

    NASA Technical Reports Server (NTRS)

    Berndt, Christopher C.

    1990-01-01

    The structure of thermally sprayed coatings consists of lamellae which are oriented parallel to the substrate surface. The lamellae separate and fracture by distinctive mechanisms which are reflected in the failure morphology, and these may be described as adhesive (between the coating and substrate), cohesive (within the coating), or mixed mode. There is a large variability in the failure stress for any nominally identical group of coatings. A lower bound for the fracture toughness of alumina coatings can be calculated as 0.2 MNm exp -3/2. The coating strength values may also be treated as belonging to the statistical distribution of the Weibull function. The Weibull modulus of the coating strength varied from 1.4 to 3.8. This analysis infers that the flaw size within coatings is highly variable and that the flaws are nonuniformly dispersed. The present work focuses on the question of whether tensile adhesion tests are an appropriate testing method for thermally sprayed materials.

  13. Modified ring stretch tensile testing of Zr-1Nb cladding

    SciTech Connect

    Cohen, A.B.; Majumdar, S.; Ruther, W.E.; Billone, M.C.; Chung, H.M.; Neimark, L.A.

    1998-03-01

    In a round robin effort between the US Nuclear Regulatory Commission, Institut de Protection et de Surete Nucleaire in France, and the Russian Research Centre-Kurchatov Institute, Argonne National Laboratory conducted 16 modified ring stretch tensile tests on unirradiated samples of zr-1Nb cladding, which is used in Russian VVER reactors. Test were conducted at two temperatures (25 and 400 C) and two strain rates (0.001 and 1 s{sup {minus}1}). At 25 C and 0.001 s{sup {minus}1}, the yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE), and total elongation (TE) were 201 MPa, 331 MPa, 18.2%, and 57.6%, respectively. At 400 C and 0.001 s{sup {minus}1}, the YS, UTS, UE, and TE were 109 MPa, 185 MPa, 15.4%, and 67.7%, respectively. Finally, at 400 C and 1 s{sup {minus}1}, the YS, UTS, UE, and TE were 134 MPa, 189 MPa, 18.9%, and 53.4%, respectively. The high strain rate tests at room temperature were not successful. Test results proved to be very sensitive to the amount of lubrication used on the inserts; because of the large contact area between the inserts and specimen, too little lubrication leads to significantly higher strengths and lower elongations being reported. It is also important to note that only 70 to 80% of the elongation takes place in the gauge section, depending on specimen geometry. The appropriate percentage can be estimated from a simple model or can be calculated from finite-element analysis.

  14. Modified ring stretch tensile testing of Zr-1Nb cladding.

    SciTech Connect

    Billone, M. C.; Chung, H. M.; Cohen, A. B.; Majumdar, S.; Neimark, L. A.; Ruther, W. E.

    1997-12-05

    In a round robin effort between the US Nuclear Regulatory Commission, Institut de Protection et de Surete Nucleaire in France, and the Russian Research Centre-Kurchatov Institute, Argonne National Laboratory conducted 16 modified ring stretch tensile tests on unirradiated samples of Zr-1Nb cladding, which is used in Russian VVER reactors. Tests were conducted at two temperatures (25 and 400 C) and two strain rates (0.001 and 1 s{sup {minus}1}). At 25 C and 0.001 s{sup {minus}1}, the yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE), and total elongation (TE) were 201 MPa, 331 MPa, 18.2%, and 57.6%, respectively. At 400 C and 0.001 s{sup {minus}1}, the YS, UTS, UE, and TE were 109 MPa, 185 MPa, 15.4%, and 67.7%, respectively. Finally, at 400 C and 1 s{sup {minus}1}, the YS, UTS, UE, and TE were 134 MPa, 189 MPa, 18.9%, and 53.4%, respectively. The high strain rate tests at room temperature were not successful. Test results proved to be very sensitive to the amount of lubrication used on the inserts; because of the large contact area between the inserts and specimen, too little lubrication leads to significantly higher strengths and lower elongations being reported. It is also important to note that only 70 to 80% of the elongation takes place in the gauge section, depending on specimen geomeq. The appropriate percentage can be estimated from a simple model or can be calculated from finite-element analysis.

  15. Novel approach to tensile testing of micro- and nanoscale fibers

    NASA Astrophysics Data System (ADS)

    Tan, E. P. S.; Lim, C. T.

    2004-08-01

    Due to the strength and size of the micro- and nanoscale fibers, larger conventional universal testing machines are not suitable in performing stretch test of such fibers. Existing microtensile testing machines are custom-made and are complex and expensive to construct. Here, a novel method of using an existing atomic force microscope (AFM)-based nanoindenation system for the tensile testing of microscale or bundled nanoscale fibers is proposed. The microscale poly (L-lactic-co-glycolic acid) fiber (˜25 μm diameter) was used as an example to illustrate this technique. The microfiber was first attached to a nanoindenter tip and the base via a custom-made holder to ensure that the microfiber was taut and vertically aligned. The force transducer of the nanoindenter was used to measure the tensile force required to stretch the microfiber. The microfiber was stretched using the stepper motor of the AFM system. The elongation of the microfiber was measured by subtracting the elongation of the transducer spring from the total elongation of the microfiber and transducer spring. A plot of the load against elongation of the microfiber was then obtained. The stress and strain of the microfiber was measured by subtracting the elongation of the transducer spring from the total elongation of the microfiber was then obtained. The stress and strain of the microfiber was obtained by dividing the load and elongation by cross-sectional area and gauge length, respectively. With this data, the mechanical behavior of the sample at small strains can be studied. This system is able to provide a high load resolution of 80 nN and displacement resolution of 0.5 nm. However, maximum load and sample elongation is limited and handling of the sample still remains a challenge.

  16. Roadmapping – A Systematic Approach to Overcoming NGNP Challenges

    SciTech Connect

    John W. Collins

    2008-09-01

    Changing requirements, programmatic challenges, and technical risk hinder even the best projects. The Next Generation Nuclear Plant (NGNP) is a complex project with technical and programmatic uncertainty. This paper presents the path forward, methods, and tools used to understand the requirements, manage the uncertainty, and mitigate the risk for the NGNP project. The key tool, technology development roadmaps, is described in detail as a means to facilitate NGNP risk-informed decision making, technology down selection, and technology qualification and maturation. Technology roadmaps for each NGNP System, Structure, or Component (SSC) were developed to set the vision for and drive the needed actions to down select technologies and designs; to assure technology readiness is demonstrated through testing, modeling, piloting, and prototyping; and to develop the test plans required to provide demonstrable evidence of the technology maturation required for codification and qualification. In the NGNP application, technology roadmaps provide the framework and structure required to systematically perform decision analysis, reduce risk, and mature technologies in a cost effective and timely manner. The steps followed include Structure Identification, Technology Readiness Assessment, Technology Selection, Technology Maturation, and Test Plan Development.

  17. The Next Generation Nuclear Plant (NGNP) Project

    SciTech Connect

    F. H. Southworth; P. E. MacDonald

    2003-11-01

    The Next Generation Nuclear Power (NGNP) Project will demonstrate emissions-free nuclearassisted electricity and hydrogen production by 2015. The NGNP reactor will be a helium-cooled, graphite moderated, thermal neutron spectrum reactor with a design goal outlet temperature of 1000 C or higher. The reactor thermal power and core configuration will be designed to assure passive decay heat removal without fuel damage during hypothetical accidents. The fuel cycle will be a once-through very high burnup low-enriched uranium fuel cycle. This paper provides a description of the project to build the NGNP at the Idaho National Engineering and Environmental Laboratory (INEEL). The NGNP Project includes an overall reactor design activity and four major supporting activities: materials selection and qualification, NRC licensing and regulatory support, fuel development and qualification, and the hydrogen production plant. Each of these activities is discussed in the paper. All the reactor design and construction activities will be managed under the DOE’s project management system as outlined in DOE Order 413.3. The key elements of the overall project management system discussed in this paper include the client and project management organization relationship, critical decisions (CDs), acquisition strategy, and the project logic and timeline. The major activities associated with the materials program include development of a plan for managing the selection and qualification of all component materials required for the NGNP; identification of specific materials alternatives for each system component; evaluation of the needed testing, code work, and analysis required to qualify each identified material; preliminary selection of component materials; irradiation of needed sample materials; physical, mechanical, and chemical testing of unirradiated and irradiated materials; and documentation of final materials selections. The NGNP will be licensed by the NRC under 10 CFR 50 or 10

  18. High Strain Rate Tensile Testing of DOP-26 Iridium

    SciTech Connect

    Schneibel, Joachim H; Carmichael Jr, Cecil Albert; George, Easo P

    2007-11-01

    The iridium alloy DOP-26 was developed through the Radioisotope Power Systems Program in the Office of Nuclear Energy of the Department of Energy. It is used for clad vent set cups containing radioactive fuel in radioisotope thermoelectric generator (RTG) heat sources which provide electric power for spacecraft. This report describes mechanical testing results for DOP-26. Specimens were given a vacuum recrystallization anneal of 1 hour at 1375 C and tested in tension in orientations parallel and perpendicular to the rolling direction of the sheet from which they were fabricated. The tests were performed at temperatures ranging from room temperature to 1090 C and strain rates ranging from 1 x 10{sup -3} to 50 s{sup -1}. Room temperature testing was performed in air, while testing at elevated temperatures was performed in a vacuum better than 1 x 10{sup -4} Torr. The yield stress (YS) and the ultimate tensile stress (UTS) decreased with increasing temperature and increased with increasing strain rate. Between 600 and 1090 C, the ductility showed a slight increase with increasing temperature. Within the scatter of the data, the ductility did not depend on the strain rate. The reduction in area (RA), on the other hand, decreased with increasing strain rate. The YS and UTS values did not differ significantly for the longitudinal and transverse specimens. The ductility and RA values of the transverse specimens were marginally lower than those of the longitudinal specimens.

  19. Tensile tests of ITER TF conductors jacket materials

    NASA Astrophysics Data System (ADS)

    Anashkin, O. P.; Kеilin, V. E.; Krivykh, A. V.; Diev, D. N.; Dinisilov, A. S.; Shcherbakov, V. I.; Tronza, V. I.

    2012-06-01

    The set of very tough requirements has been formulated for TF jacket materials with extremely high plasticity at liquid helium temperature. The stainless steel 316LN-IG is recommended to be used for TF jacket tubes. Samples of 316LN-IG tubes (whole tubes and sub-size samples) made of the material from the same electro slag remelt have been tested in different conditions - as received tubes and tubes after prescribed compaction, 2.5% deformation at room temperature and heat treatment at 650 0C, 200 hours. The tensile tests were carried out at room, liquid nitrogen and liquid helium temperatures down to 4.2 K, meeting corresponding ASME and ASTM requirements. The low temperature testing devices are described. The tests results for sub-size samples and whole tubes show that the latter tests are considerably more representative and important for butt weld qualification at LHe temperature. It was observed that the ferromagnetic properties of all samples and especially of butt welds increase with lowering the temperature and increasing the degree of deformation. At LHe temperature a non-uniform and highly localized serrated deformations were observed.

  20. TENSILE TESTING OF CARBON STEEL IN HIGH PRESSURE HYDROGEN

    SciTech Connect

    Duncan, A; Thad Adams, T; Ps Lam, P

    2007-05-02

    An infrastructure of new and existing pipelines and systems will be required to carry and to deliver hydrogen as an alternative energy source under the hydrogen economy. Carbon and low alloy steels of moderate strength are currently used in hydrogen delivery systems as well as in the existing natural gas systems. It is critical to understand the material response of these standard pipeline materials when they are subjected to pressurized hydrogen environments. The methods and results from a testing program to quantify hydrogen effects on mechanical properties of carbon steel pipeline and pipeline weld materials are provided. Tensile properties of one type of steel (A106 Grade B) in base metal, welded and heat affected zone conditions were tested at room temperature in air and high pressure (10.34 MPa or 1500 psig) hydrogen. A general reduction in the materials ability to plastically deform was noted in this material when specimens were tested in hydrogen. Furthermore, the primary mode of fracture was changed from ductile rupture in air to cleavage with secondary tearing in hydrogen. The mechanical test results will be applied in future analyses to evaluate service life of the pipelines. The results are also envisioned to be part of the bases for construction codes and structural integrity demonstrations for hydrogen service pipeline and vessels.

  1. Direct laboratory tensile testing of select yielding rock bolt systems

    SciTech Connect

    VandeKraats, J.D.; Watson, S.O.

    1996-08-01

    Yielding rock bolt support systems have been developed to accommodate ground movement in shifting ground such as in coal operations; in creeping ground such as salt, trona, and potash; and in swelling ground associated with some clays. These systems, designed to remain intact despite ground movement, should enhance mine safety and help contain costs in areas where rebolting of rigid non-yielding systems is typically required. Four such systems were tested in straight tensile pulls in the laboratory. They include the Slip Nut System from Dywidag Systems International USA, Inc., Ischebeck`s bolt mounted Titan Load Indicator, Rocky Mountain Bolt Company`s Yielding Cable Bolt, and a rock bolt installed variation of the yielding steel post developed by RE/SPEC Inc. The first two systems are currently marketed products and the latter two are prototype systems. Each system responds to load and displacement by yielding in an unique manner. All are designed to yield at predetermined loads. A description of each system and its yield function is provided. Each system was tested over its prescribed yield range in a test machine. At least five tests were performed on each system. Each system yielded and continued to provide support according to its design. Each shows promise for ground control use in shifting or creeping rock. This work helps to illustrate the comparative differences in performance between these specialized systems and the applications where they may be most useful.

  2. Impact Tensile Testing of Stainless Steels at Various Temperatures

    SciTech Connect

    D. K. Morton

    2008-03-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern (1 to 300 per second) are not well documented. However, research is being performed at the Idaho National Laboratory to quantify these characteristics. The work presented herein discusses tensile impact testing of dual-marked 304/304L and 316/316L stainless steel material specimens. Both base material and welded material specimens were tested at -20 oF, room temperature, 300 oF, and 600 oF conditions. Utilizing a drop weight impact test machine and 1/4-inch and 1/2-inch thick dog bone-shaped test specimens, a strain rate range of approximately 4 to 40 per second (depending on initial temperature conditions) was achieved. Factors were determined that reflect the amount of increased strain energy the material can absorb due to strain rate effects. Using the factors, elevated true stress-strain curves for these materials at various strain rates and temperatures were generated. By incorporating the strain rate elevated true stress-strain material curves into an inelastic finite element computer program as the defined material input, significant improvement in the accuracy of the computer analyses was attained. However, additional impact testing is necessary to achieve higher strain rates (up to 300 per second) before complete definition of strain rate effects can be made for accidental drop events and other similar energy-limited impulsive loads. This research approach, using impact testing and a total energy analysis methodology to quantify strain rate effects, can be applied to many other materials used in government and industry.

  3. Calibration of DEM simulation: Unconfined Compressive Test and Brazilian Tensile Test

    NASA Astrophysics Data System (ADS)

    Wang, Yucang; Alonso-Marroquín, Fernando

    2009-06-01

    We simulate rock fracture using ESyS_Particle, which is a 3-D Discrete Element Model developed for modeling geological materials. Two types of simulations are carried out: Unconfined Compressive Test (UCT) and Brazilian Tensile Test (BTT). The results are compared to laboratory tests. Model parameters are determined on the basis of theoretical studies on the elastic properties of regular lattices and dimensionless analysis. The fracture patterns and realistic macroscopic strength are well reproduced. Also the ratio of the macroscopic strength of compression to the tensile strength is obtained numerically.

  4. Effect of cantilever nonlinearity in nanoscale tensile testing

    NASA Astrophysics Data System (ADS)

    Ding, Weiqiang; Guo, Zaoyang; Ruoff, Rodney S.

    2007-02-01

    Microcantilevers are widely used in micro-/nanoscale mechanics studies. The nonlinear response of a cantilever at large deflection is sometimes overlooked. A general study of cantilever beam nonlinearity under a variety of loading conditions was performed with analytical and finite element analyses. Analytical equations for the applied load and the cantilever deflection were obtained. The cantilever nonlinearity was found to increase with increasing cantilever deflection and/or angle of loading. Tensile tests were performed on templated carbon nanotubes (TCNTs) with a custom-made nanomanipulator inside a scanning electron microscope. Atomic force microscope (AFM) cantilevers were used to load the TCNTs and sense the force. During the tests the AFM cantilevers were loaded to relatively large deflections with nonvertical loads applied at the AFM tip. Based on the slope and the loading angle measurements, the breaking forces of the TCNTs were obtained through numerical integration of the analytical equations. A comparison was made between the load results obtained from linear and nonlinear analyses. The linear analysis was found to underestimate the applied load by up to 15%.

  5. New experimental protocols for tensile testing of abdominal aortic analogues.

    PubMed

    Bailly, L; Deplano, V; Lemercier, A; Boiron, O; Meyer, C

    2014-06-01

    This work proposes an in vitro tensile testing protocol that is able to characterize abdominal aortic (AA) analogues under physiologically inspired mechanical loadings. Kinematic parameters are defined in agreement with in vivo measurements of aortic dynamics. A specific focus is given to the choice of the applied loading rates, deriving from the knowledge of aortic Peterson modulus and blood pressure variations from diastolic to systolic instants. The influence of physiological elongation rates has been tested on both porcine AAs and a thermoplastic polyurethane (TPU) material used to elaborate AA analogues. The diastolic and systolic elongation rates estimates vary between orders of magnitude O(10(-2)) and O(10(-1))s(-1). Negligible differences are obtained when comparing stress-elongation responses between both physiological elongation rates. In contrast, a noticeable stiffening of the TPU mechanical response is observed compared to that obtained under the common low traction rate of O(10(-3))s(-1). This work shows how relevant physiological elongation rates can be evaluated as a function of age, gender and pathological context. PMID:24613685

  6. Hoop tensile strength testing of small diameter ceramic particles

    NASA Astrophysics Data System (ADS)

    Wereszczak, A. A.; Jadaan, O. M.; Lin, H.-T.; Champoux, G. J.; Ryan, D. P.

    2007-03-01

    A method to measure hoop tensile strength of 1-mm-diameter brittle ceramic spheres was demonstrated through the use of a 'C-sphere' flexure strength specimen. This innovative specimen geometry was chosen because a simple, monotonically increasing uniaxial compressive force produces a hoop tensile stress at the C-sphere's outer surface that ultimately initiates fracture. This enables strength quantification and strength-limiting-flaw identification of the sphere itself. Such strength information is relevant to design optimization and durability assessments of ceramic fuel particles and breeder/multiplier pebbles for fusion when particle surfaces are subjected to tensile stresses during their manufacturing or service.

  7. Tensile testing of nylon and Kevlar parachute materials under Federal specified temperature and relative humidity conditions

    SciTech Connect

    Botner, W.T.

    1980-01-01

    A small 10-ft x 12-ft temperature and relative humidity controlled room for tensile testing of parachute materials is presented. Tensile tests of nylon and Kevlar parachute materials indicate there is a negligible change in break strength of test samples soaked in the controlled environment vs samples soaked in ambient conditions.

  8. Biaxial tensile tests of the porcine ascending aorta.

    PubMed

    Deplano, Valérie; Boufi, Mourad; Boiron, Olivier; Guivier-Curien, Carine; Alimi, Yves; Bertrand, Eric

    2016-07-01

    One of the aims of this work is to develop an original custom built biaxial set-up to assess mechanical behavior of soft tissues. Stretch controlled biaxial tensile tests are performed and stereoscopic digital image correlation (SDIC) is implemented to measure the 3D components of the generated displacements. Using this experimental device, the main goal is to investigate the mechanical behavior of porcine ascending aorta in the more general context of human ascending aorta pathologies. The results highlight that (i) SDIC arrangement allows accurate assessment of displacements and so stress strain curves, (ii) porcine ascending aorta has a nearly linear and anisotropic mechanical behavior until 30% of strain, (iii) porcine ascending aorta is stiffer in the circumferential direction than in the longitudinal one, (iv) the material coefficient representing the interaction between the two loading directions is thickness dependent, (v) taking into account the variability of the samples the stress values are independent of the stretch rate in the range of values from 10(-3) to 10(-1)s(-1) and finally, (vi) unlike other segments of the aorta, 4-month-old pigs ascending aorta is definitely not a relevant model to investigate the mechanical behavior of the human ascending aorta. PMID:27211783

  9. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

    DOEpatents

    Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Asif, Syed Amanula Syed

    2013-05-07

    A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

  10. Micro/nano-mechanical test system employing tensile test holder with push-to-pull transformer

    DOEpatents

    Oh, Yunje; Cyrankowski, Edward; Shan, Zhiwei; Syed Asif, Syed Amanula

    2014-07-29

    A micromachined or microelectromechanical system (MEMS) based push-to-pull mechanical transformer for tensile testing of micro-to-nanometer scale material samples including a first structure and a second structure. The second structure is coupled to the first structure by at least one flexible element that enables the second structure to be moveable relative to the first structure, wherein the second structure is disposed relative to the first structure so as to form a pulling gap between the first and second structures such that when an external pushing force is applied to and pushes the second structure in a tensile extension direction a width of the pulling gap increases so as to apply a tensile force to a test sample mounted across the pulling gap between a first sample mounting area on the first structure and a second sample mounting area on the second structure.

  11. Scalability of the natural convection shutdown heat removal test facility (NSTF) data to VHTR/NGNP RCCS designs.

    SciTech Connect

    Vilim, R .B.; Feldman, E. E.; Nuclear Engineering Division

    2007-08-07

    Passive safety in the Very High Temperature Reactor (VHTR) is strongly dependent on the thermal performance of the Reactor Cavity Cooling System (RCCS). Scaled experiments performed in the Natural Shutdown Test Facility (NSTF) are to provide data for assessing and/or improving computer code models for RCCS phenomena. Design studies and safety analyses that are to support licensing of the VHTR will rely on these models to achieve a high degree of certainty in predicted design heat removal rate. To guide in the selection and development of an appropriate set of experiments a scaling analysis has been performed for the air-cooled RCCS option. The goals were to (1) determine the phenomena that dominate the behavior of the RCCS, (2) determine the general conditions that must be met so that these phenomena and their relative importance are preserved in the experiments, (3) identify constraints specific to the NSTF that potentially might prevent exact similitude, and (4) then to indicate how the experiments can be scaled to prevent distortions in the phenomena of interest. The phenomena identified as important to RCCS operation were also the subject of a recent PIRT study. That work and the present work collectively indicate that the main phenomena influencing RCCS heat removal capability are (1) radiation heat transport from the vessel to the air ducts, (2) the integral effects of momentum and heat transfer in the air duct, (3) buoyancy at the wall inside the air duct giving rise to mixed convection, and (4) multidimensional effects inside the air duct caused by non-uniform circumferential heat flux and non-circular geometry.

  12. A cryogenic tensile testing apparatus for micro-samples cooled by miniature pulse tube cryocooler

    NASA Astrophysics Data System (ADS)

    Chen, L. B.; Liu, S. X.; Gu, K. X.; Zhou, Y.; Wang, J. J.

    2015-12-01

    This paper introduces a cryogenic tensile testing apparatus for micro-samples cooled by a miniature pulse tube cryocooler. At present, tensile tests are widely applied to measure the mechanical properties of materials; most of the cryogenic tensile testing apparatus are designed for samples with standard sizes, while for non-standard size samples, especially for microsamples, the tensile testing cannot be conducted. The general approach to cool down the specimens for tensile testing is by using of liquid nitrogen or liquid helium, which is not convenient: it is difficult to keep the temperature of the specimens at an arbitrary set point precisely, besides, in some occasions, liquid nitrogen, especially liquid helium, is not easily available. To overcome these limitations, a cryogenic tensile testing apparatus cooled by a high frequency pulse tube cryocooler has been designed, built and tested. The operating temperatures of the developed tensile testing apparatus cover from 20 K to room temperature with a controlling precision of ±10 mK. The apparatus configurations, the methods of operation and some cooling performance will be described in this paper.

  13. Establishing Correlations for Predicting Tensile Properties Based on the Shear Punch Test and Vickers Microhardness data

    NASA Astrophysics Data System (ADS)

    Milot, Timothy S.

    A series of mechanical tests was performed on a matrix of pressure vessel alloys to establish correlations between shear punch tests (SPT), microhardness (Hv), and tensile data. The purpose is to estimate tensile properties from SPT and Hv data. Small specimen testing is central to characterization of irradiation-induced changes in alloys used for nuclear applications. SPT have the potential for estimating tensile yield and ultimate strengths, strain hardening and ductility data, by using TEM disks, for example. Additional insight into SPT was gained by performing finite element analysis (FEA) simulations.

  14. Test system accurately determines tensile properties of irradiated metals at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Levine, P. J.; Skalka, R. J.; Vandergrift, E. F.

    1967-01-01

    Modified testing system determines tensile properties of irradiated brittle-type metals at cryogenic temperatures. The system includes a lightweight cryostat, split-screw grips, a universal joint, and a special temperature control system.

  15. In situ TEM tensile testing of carbon-linked graphene oxide nanosheets using a MEMS device

    NASA Astrophysics Data System (ADS)

    Cao, Changhong; Howe, Jane Y.; Perovic, Doug; Filleter, Tobin; Sun, Yu

    2016-07-01

    This paper reports in situ transmission electron microscopy (TEM) tensile testing of carbon-linked graphene oxide nanosheets using a monolithic TEM compatible microelectromechanical system device. The set-up allows direct on-chip nanosheet thickness mapping, high resolution electron beam linking of a pre-fractured nanosheet, and mechanical tensile testing of the nanosheet. This technique enables simultaneous mechanical and high energy electron beam characterization of 2D nanomaterials.

  16. In situ TEM tensile testing of carbon-linked graphene oxide nanosheets using a MEMS device.

    PubMed

    Cao, Changhong; Howe, Jane Y; Perovic, Doug; Filleter, Tobin; Sun, Yu

    2016-07-15

    This paper reports in situ transmission electron microscopy (TEM) tensile testing of carbon-linked graphene oxide nanosheets using a monolithic TEM compatible microelectromechanical system device. The set-up allows direct on-chip nanosheet thickness mapping, high resolution electron beam linking of a pre-fractured nanosheet, and mechanical tensile testing of the nanosheet. This technique enables simultaneous mechanical and high energy electron beam characterization of 2D nanomaterials. PMID:27256541

  17. Design and use of nonstandard tensile specimens for irradiated materials testing

    SciTech Connect

    Panayotou, N.F.; Atkin, S.D.; Puigh, R.J.

    1983-08-01

    Two types of miniature specimens been developed to utilize the limited irradiation volume of high energy neutron sources such as the Rotating Target Neutron Source (RTNS)-II and the Fusion Materials Irradiation Test (FMIT) facility. Wire-type specimens have been used to obtain tensile data for several metals irradiated at RTNS-II. Difficulties in the control of wire specimen dimensions led to the design of a miniature tensile specimen which could be fabricated from 0.25 mm thick sheet stock. Sheet-type tensile specimens are currently our standard tensile specimen for high energy neutron source experiments. These specimens are fabricated, like transmission electron microscopy (TEM) disks, by a punching technique. Precise test frame alignment is essential if reproducible test data are to be obtained. The dedicated test frame developed for miniature tensile specimen testing is briefly described. Miniature tensile specimens of a range of metals have been fabricated and tested. The data are reproducible and are in good agreement with data obtained from larger specimens.

  18. Tensile Properties, Ferrite Contents, and Specimen Heating of Stainless Steels in Cryogenic Gas Tests

    NASA Astrophysics Data System (ADS)

    Ogata, T.; Yuri, T.; Ono, Y.

    2006-03-01

    We performed tensile tests at cryogenic temperatures below 77 K and in helium gas environment for SUS 304L and SUS 316L in order to obtain basic data of mechanical properties of the materials for liquid hydrogen tank service. We evaluate tensile curves, tensile properties, ferrite contents, mode of deformation and/or fracture, and specimen heating during the testing at 4 to 77 K. For both SUS 304L and 316L, tensile strength shows a small peak around 10 K, and specimen heating decreases above 30 K. The volume fraction of α-phase increases continuously up to 70 % with plastic strain, at approximately 15 % plastic strain for 304L and up to 35 % for 316L. There was almost no clear influence of testing temperature on strain-induced martensitic transformation at the cryogenic temperatures.

  19. Intrinsic tensile properties of cocoon silk fibres can be estimated by removing flaws through repeated tensile tests.

    PubMed

    Rajkhowa, Rangam; Kaur, Jasjeet; Wang, Xungai; Batchelor, Warren

    2015-06-01

    Silk fibres from silkworm cocoons have lower strength than spider silk and have received less attention as a source of high-performance fibres. In this work, we have used an innovative procedure to eliminate the flaws gradually of a single fibre specimen by retesting the unbroken portion of the fibre, after each fracture test. This was done multiple times so that the final test may provide the intrinsic fibre strength. During each retest, the fibre specimen began to yield once the failure load of the preceding test was exceeded. For each fibre specimen, a composite curve was constructed from multiple tests. The composite curves and analysis show that strengths of mass-produced Muga and Eri cocoon silk fibres increased from 446 to 618 MPa and from 337 to 452 MPa, respectively. Similarly, their toughness increased from 84 to 136 MJ m(-3) and from 61 to 104 MJ m(-3), respectively. Composite plots produced significantly less inter-specimen variations compared to values from single tests. The fibres with reduced flaws as a result of retests in the tested section have a tensile strength and toughness comparable to naturally spun dragline spider silk with a reported strength of 574 MPa and toughness of 91-158 MJ m(-3), which is used as a benchmark for developing high-performance fibres. This retesting approach is likely to provide useful insights into discrete flaw distributions and intrinsic mechanical properties of other fatigue-resistant materials. PMID:25948613

  20. Intrinsic tensile properties of cocoon silk fibres can be estimated by removing flaws through repeated tensile tests

    PubMed Central

    Rajkhowa, Rangam; Kaur, Jasjeet; Wang, Xungai; Batchelor, Warren

    2015-01-01

    Silk fibres from silkworm cocoons have lower strength than spider silk and have received less attention as a source of high-performance fibres. In this work, we have used an innovative procedure to eliminate the flaws gradually of a single fibre specimen by retesting the unbroken portion of the fibre, after each fracture test. This was done multiple times so that the final test may provide the intrinsic fibre strength. During each retest, the fibre specimen began to yield once the failure load of the preceding test was exceeded. For each fibre specimen, a composite curve was constructed from multiple tests. The composite curves and analysis show that strengths of mass-produced Muga and Eri cocoon silk fibres increased from 446 to 618 MPa and from 337 to 452 MPa, respectively. Similarly, their toughness increased from 84 to 136 MJ m−3 and from 61 to 104 MJ m−3, respectively. Composite plots produced significantly less inter-specimen variations compared to values from single tests. The fibres with reduced flaws as a result of retests in the tested section have a tensile strength and toughness comparable to naturally spun dragline spider silk with a reported strength of 574 MPa and toughness of 91–158 MJ m−3, which is used as a benchmark for developing high-performance fibres. This retesting approach is likely to provide useful insights into discrete flaw distributions and intrinsic mechanical properties of other fatigue-resistant materials. PMID:25948613

  1. New Materials for NGNP/Gen IV

    SciTech Connect

    Robert W. Swindeman; Douglas L. Marriott

    2009-12-18

    The bounding conditions were briefly summarized for the Next Generation Nuclear Plant (NGNP) that is the leading candidate in the Department of Energy Generation IV reactor program. Metallic materials essential to the successful development and proof of concept for the NGNP were identified. The literature bearing on the materials technology for high-temperature gas-cooled reactors was reviewed with emphasis on the needs identified for the NGNP. Several materials were identified for a more thorough study of their databases and behavioral features relative to the requirements ASME Boiler and Pressure Vessel Code, Section III, Division 1, Subsection NH.

  2. Annealing and Test Temperature Dependence of Tensile Properties of UNS N04400 Alloy

    NASA Astrophysics Data System (ADS)

    Afzal, Naveed; Ahmad, R.; Akhtar, Tanveer; Ayub, R.; Ghauri, I. M.

    2013-07-01

    Effects of annealing and test temperatures on the tensile behavior of UNS N04400 alloy have been examined. The specimens were annealed at 800, 1000, and 1200 °C for 4 h under vacuum in a muffle furnace. Stress-strain curves of the specimens were obtained in the temperature range 25-300 °C using a universal testing machine fitted with a thermostatic chamber. The results indicate that the yield strength (YS), ultimate tensile strength (UTS), and percentage elongation of the specimens decrease with increase of annealing temperature. By increasing the test temperature, the YS and UTS decrease, whereas the percentage elongation initially decreases with increase of test temperature from 25 to 100 °C and then increases with further increasing the temperature up to 300 °C. The changes in the tensile properties of the alloy are associated with the post-annealing microstructure and modes of fracture.

  3. Instrumented impact and residual tensile strength testing of eight-ply carbon eopoxy specimens

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    1990-01-01

    Instrumented drop weight impact testing was utilized to examine a puncture-type impact on thin carbon-epoxy coupons. Four different material systems with various eight-ply lay-up configurations were tested. Specimens were placed over a 10.3-mm diameter hole and impacted with a smaller tup (4.2-mm diameter) than those used in previous studies. Force-time plots as well as data on absorbed energy and residual tensile strength were gathered and examined. It was found that a critical impact energy level existed for each material tested, at which point tensile strength began to rapidly decrease with increasing impact energy.

  4. NGNP SITE 2 HAZARDS ASSESSMENT

    SciTech Connect

    Wayne Moe

    2011-10-01

    The Next Generation Nuclear Plant (NGNP) Project initiated at Idaho National Laboratory (INL) by the U.S. Department of Energy pursuant to the 2005 Energy Policy Act, is based on research and development activities supported by the Generation IV Nuclear Energy Systems Initiative. The principal objective of the NGNP Project is to support commercialization of the high temperature gas-cooled reactor (HTGR) technology. The HTGR is a helium-cooled and graphite-moderated reactor that can operate at temperatures much higher than those of conventional light water reactor (LWR) technologies. Accordingly, it can be applied in many industrial applications as a substitute for burning fossil fuels, such as natural gas, to generate process heat in addition to producing electricity, which is the principal application of current LWRs. Nuclear energy in the form of LWRs has been used in the U.S. and internationally principally for the generation of electricity. However, because the HTGR operates at higher temperatures than LWRs, it can be used to displace the use of fossil fuels in many industrial applications. It also provides a carbon emission-free energy supply. For example, the energy needs for the recovery and refining of petroleum, for the petrochemical industry and for production of transportation fuels and feedstocks using coal conversion processes require process heat provided at temperatures approaching 800 C. This temperature range is readily achieved by the HTGR technology. This report summarizes a site assessment authorized by INL under the NGNP Project to determine hazards and potential challenges that site owners and HTGR designers need to be aware of when developing the HTGR design for co-location at industrial facilities, and to evaluate the site for suitability considering certain site characteristics. The objectives of the NGNP site hazard assessments are to do an initial screening of representative sites in order to identify potential challenges and restraints

  5. Evaluation of damage models by finite element prediction of fracture in cylindrical tensile test.

    PubMed

    Eom, Jaegun; Kim, Mincheol; Lee, Seongwon; Ryu, Hoyeun; Joun, Mansoo

    2014-10-01

    In this research, tensile tests of cylindrical specimens of a mild steel are predicted via the finite element method, with emphasis on the fracture predictions of various damage models. An analytical model is introduced for this purpose. An iterative material identification procedure is used to obtain the flow stress, making it possible to exactly predict a tensile test up to the fracture point, in the engineering sense. A node-splitting technique is used to generate the cracks on the damaged elements. The damage models of McClintock, Rice-Tracey, Cockcroft-Latham, Freudenthal, Brozzo et al. and Oyane et al. are evaluated by comparing their predictions from the tensile test perspective. PMID:25942914

  6. Effects of reclaimed asphalt pavement on indirect tensile strength test of conditioned foamed asphalt mix

    NASA Astrophysics Data System (ADS)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    This paper presents the results of Indirect Tensile Strength (ITS) Test for samples prepared with reclaimed asphalt pavement (RAP). Samples were conditioned in water at 25°C for 24 hours prior to testing. Results show that recycled aggregate from reclaimed asphalt pavement performs as well as virgin aggregate.

  7. A combined analytical-experimental tensile test technique for brittle materials

    NASA Technical Reports Server (NTRS)

    Chu, M. L.; Scavuzzo, R. J.; Srivatsan, T. S.

    1992-01-01

    A semiconventional tensile test technique is developed for impact ices and other brittle materials. Accurate results have been obtained on ultimate strength and modulus of elasticity in a refrigerated ice test. It is noted that the technique can be used to determine the physical properties of impact ices accreted inside icing wind tunnels or other brittle materials.

  8. Tensile adhesion test measurements on plasma-sprayed coatings

    NASA Technical Reports Server (NTRS)

    Berndt, C. C.

    1986-01-01

    Adhesion measurements on plasma-sprayed coatings are briefly studied, including a critical analysis of the experimental scatter for duplicate tests. The application of a simple method which presents adhesion strength data in a fracture mechanics perspective is demonstrated. Available data are analyzed in a way which suggests an approach to finding the overall defect contribution to reducing the apparent strength of coatings.

  9. NGNP Infrastructure Readiness Assessment: Consolidation Report

    SciTech Connect

    Brian K Castle

    2011-02-01

    The Next Generation Nuclear Plant (NGNP) project supports the development, demonstration, and deployment of high temperature gas-cooled reactors (HTGRs). The NGNP project is being reviewed by the Nuclear Energy Advisory Council (NEAC) to provide input to the DOE, who will make a recommendation to the Secretary of Energy, whether or not to continue with Phase 2 of the NGNP project. The NEAC review will be based on, in part, the infrastructure readiness assessment, which is an assessment of industry's current ability to provide specified components for the FOAK NGNP, meet quality assurance requirements, transport components, have the necessary workforce in place, and have the necessary construction capabilities. AREVA and Westinghouse were contracted to perform independent assessments of industry's capabilities because of their experience with nuclear supply chains, which is a result of their experiences with the EPR and AP-1000 reactors. Both vendors produced infrastructure readiness assessment reports that identified key components and categorized these components into three groups based on their ability to be deployed in the FOAK plant. The NGNP project has several programs that are developing key components and capabilities. For these components, the NGNP project have provided input to properly assess the infrastructure readiness for these components.

  10. Effects of Thermal Treatment on Tensile Strength of Laurentian Granite Using Brazilian Test

    NASA Astrophysics Data System (ADS)

    Yin, Tubing; Li, Xibing; Cao, Wenzhuo; Xia, Kaiwen

    2015-11-01

    The effect of thermal treatment on several physical properties and the tensile strength of Laurentian granite (LG) are measured in this study. Brazilian disc LG specimens are treated at temperatures of up to 850 °C. The physical properties such as grain density, relative volume change per degree, and P-wave velocity are investigated under the effect of heat treatment. The results indicate that both the density and the P-wave velocity decrease with the increase in heating temperature. However, the relative volume change per degree is not sensitive below 450 °C, while a remarkable increase appears from 450 to 850 °C. All cases are explained by the increase in both number and width of the thermally induced microcracks with the heating temperature. Brazilian tests are carried out statically with an MTS hydraulic servo-control testing system and dynamically with a modified split Hopkinson pressure bar (SHPB) system to measure both static and dynamic tensile strength of LG. The relationship between the tensile strength and treatment temperatures shows that static tensile strength decreases with temperature while the dynamic tensile strength first increases and then decreases with a linear increase in the loading rate. However, the increase in dynamic tensile strength with treatment temperatures from 25 to 100 °C is due to slight dilation of the grain boundaries as the initial thermal action, which leads to compaction of rock. When the treatment temperature rises above 450 °C, the quartz phase transition results in increased size of microcracks due to the differential expansion between the quartz grains and other minerals, which is the main cause of the sharp reduction in tensile strength.

  11. Dynamic tensile test of single PET textile cables

    NASA Astrophysics Data System (ADS)

    Guégan, P.; Othman, R.; Pasco, F.; Bruant, R.

    2012-08-01

    The tyres conception involves for certain applications, the use of textile cables as reinforcement. During its use, the tyre undergoes temperatures variations and dynamic loading rates. The consideration of these conditions during the numeric simulations requires the knowledge of the sensitivity of the mechanical behaviour to loading rate and temperature. In this paper, we developed an experimental methodology for testing textile cable up to high strain rate. The main difficulty of testing cables is the optimization of cable fixing on the machine. For that purpose, we adapted the solution of fixing by progressive binding already used in quasi-static, while taking into account constraints inherent to high strain tests. Firstly, the mass of grips was decreased in order to get force signal less sensitive to grips inertia. The method was developed on a high speed hydraulic machine equipped with a thermal enclosure. The investigated temperatures and strain rates range from room temperature to 373 ∘K (100 ∘C) and from 0,01 to 100/s, respectively. In addition, the hydraulic machine was equipped with a high speed video camera. The obtained images were analysed by a tracking technique to measure the average strain in the cable (from 50 to 20000 f/s).

  12. Microstructural evolutions and stability of gradient nano-grained copper under tensile tests and subsequent storage

    NASA Astrophysics Data System (ADS)

    Chen, W.; You, Z. S.; Tao, N. R.; Lu, L.

    2015-08-01

    A gradient nano-grained (GNG) surface layer is produced on a bulk coarse-grained Cu by means of a surface mechanical grinding treatment. Homogeneous grain coarsening induced by mechanical deformation is observed in the GNG Cu layer under tensile tests at both 300 K and 123 K. The concurrent grain coarsening during tensile deformation is proven to be also thermally activated, because the extent of grain coarsening of the GNG Cu layer is less significant at 123 K than at 300 K, although a higher flow stress is achieved at 123 K. During the subsequent storage at 258 K after tensile tests, no obvious change can be found for the grain size in the GNG Cu layer deformed at 300 K. In contrast, widespread abnormal grain coarsening is frequently observed in the GNG Cu layer deformed at 123 K and stored for 100 days, which may be caused by the higher stored energy in the non-equilibrium grain boundary structures.

  13. In situ tensile testing of individual Co nanowires inside a scanning electron microscope.

    PubMed

    Zhang, Dongfeng; Breguet, Jean-Marc; Clavel, Reymond; Phillippe, Laetitia; Utke, Ivo; Michler, Johann

    2009-09-01

    Uniaxial quasi-static tensile testing on individual nanocrystalline Co nanowires (NWs), synthesized by electrochemical deposition process (EDP) in porous templates, was performed inside a scanning electron microscope (SEM) using a microfabricated tensile stage consisting of a comb drive actuator and a clamped-clamped beam force sensor. A 'three-beam structure' was fabricated by focused ion beam induced deposition (FIBID) on the stage, from which the specimen elongation and the tensile force could be measured simultaneously from SEM images at high magnification. A novel strategy of modifying device topography, e.g. in the form of trenches and pillars, was proposed to facilitate in situ SEM pick-and-place nanomanipulation, which could achieve a high yield of about 80% and reduce the difficulties in specimen preparation for tensile testing at the nanoscale. The measured apparent Young's modulus (75.3 +/- 14.6) GPa and tensile strength (1.6 +/- 0.4) GPa are significantly lower than the bulk modulus and the theoretical strength of monocrystalline samples, respectively. This result is important for designing Co NW-based devices. The origins of these distinctions are discussed in terms of the stiffnesses of the soldering portions, specimen misalignment, microstructure of the NWs and the experimental measurement uncertainty. PMID:19687546

  14. Tensile test of SS 316LN jacket with different conditions

    NASA Astrophysics Data System (ADS)

    Qin, Jinggang; Dai, Chao; Liao, Guojun; Wu, Yu; Zhu, Xiaofeng; Huang, Chuanjun; Li, Laifeng; wang, Kun; Shen, Xiaogang; Tu, Zhengpin; Ji, Hui

    2014-11-01

    316LN stainless steel is selected as a material for Toroidal-field (TF) conductor jacket of International Thermonuclear Experimental Reactor (ITER). When energized, the ITER TF coils experience large pulsed electromagnetic forces that the conductor jacket itself must withstand. The conductor will be compacted, spooled and aged at approximately 650 °C during manufacture. Therefore, the sample jackets were prepared under compaction, stretching and annealing to simulate the manufacturing process and operation of TF coils. The present Chinese TF jacket has good performance under standard conditions. In order to investigate more mechanical properties of 316LN jacket, the different cold working and annealing were applied to the raw materials. The samples were measured at 4.2 K, 77 K and 300 K. Youngs modulus, yield strength (0.2% offset), elongation at failure and SEM images are reported. There is no big deviation among different conditions. The test results show that Chinese TF jacket has good performance.

  15. Tensile tests of niobium material for SRF cavities

    SciTech Connect

    Wu, G.; Dhanaraj, N.; Cooley, L.; Hicks, D.; Hahn, E.; Burk, D.; Muranyi, W.; Foley, N.; Edwards, H.; Harms, E.; Champion, M.; /Fermilab /Michigan State U.

    2009-06-01

    Mechanical tests of cavity-grade niobium samples were conducted to provide engineering information for the certification of 3rd-harmonic superconducting radio-frequency cavities and cryomodules. Large changes of mechanical properties occur throughout the cavity fabrication process due to the cold work introduced by forming, the heating introduced by electron beam welding, and the recovery of cold work during the anneal used to degas hydrogen after chemical processing. Data is provided here to show the different properties at various stages of fabrication, including both weld regions and samples from the bulk niobium far away from the weld. Measurements of RRR were used to assure that any contamination during annealing was negligible.

  16. Tensile Tests of Niobium Material for Srf Cavities

    NASA Astrophysics Data System (ADS)

    Wu, G.; Dhanaraj, N.; Cooley, L.; Hicks, D.; Hahn, E.; Burk, D.; Muranyi, W.; Foley, M.; Edwards, H.; Harms, E.; Champion, M.; Baars, D.; Compton, C.

    2010-04-01

    Mechanical tests of cavity-grade niobium samples were conducted to provide engineering information for the certification of 3rd-harmonic superconducting radio-frequency cavities and cryomodules. Large changes of mechanical properties occur throughout the cavity fabrication process due to the cold work introduced by forming, the heating introduced by electron beam welding, and the recovery of cold work during the anneal used to degas hydrogen after chemical processing. Data is provided here to show the different properties at various stages of fabrication, including both weld regions and samples from the bulk niobium far away from the weld. Measurements of RRR were used to assure that any contamination during annealing was negligible.

  17. Mechanical Testing of TR-55 Rubber Thermally Aged Under Tensile Strain

    SciTech Connect

    Small IV, W; Alviso, C T; Wilson, T S; Chinn, S C; Maxwell, R S

    2009-03-10

    TR-55 rubber specimens were previously subjected to an aging process consisting of the application of a tensile strain of approximately 67%, 100%, 133%, or 167% elongation for 4, 8, 12, or 16 h at either 250 C or room temperature. Control specimens at the same temperatures/durations were not subjected to tensile strain. The specimens were allowed to recover at room temperature without external stimuli for over 100 days before tensile testing. A single dog bone was cut from each specimen and a stress-strain curve was obtained. The elastic modulus of each specimen was calculated. Specimens aged under tensile strain exhibited rubber-like behavior dependent on the aging elongation and duration. This behavior was not evident in the unstrained controls. For the unstrained controls, exposure to 250 C resulted in an increase in modulus relative to the unheated material independent of the heating duration. The tensile strain applied during the aging process caused a reduction in modulus relative to the controls; lower moduli were observed for the shorter aging durations. Slippage of the specimens in the grips prevented determination of ultimate strength, as all specimens either slipped completely out of the grip before failure or failed at the original grip edge after slipping.

  18. On-wafer time-dependent high reproducibility nano-force tensile testing

    NASA Astrophysics Data System (ADS)

    Bergers, L. I. J. C.; Hoefnagels, J. P. M.; Geers, M. G. D.

    2014-12-01

    Time-dependent mechanical investigations of on-wafer specimens are of interest for improving the reliability of thin metal film microdevices. This paper presents a novel methodology, addressing key challenges in creep and anelasticity investigations through on-wafer tensile tests, achieving highly reproducible force and specimen deformation measurements and loading states. The methodology consists of a novel approach for precise loading using a pin-in-hole gripper and a high-precision specimen alignment system based on three-dimensional image tracking and optical profilometry resulting in angular alignment of <0.1 mrad and near-perfect co-linearity. A compact test system enables in situ tensile tests of on-wafer specimens under light and electron microscopy. Precision force measurement over a range of 0.07 µN to 250 mN is realized based on a simple drift-compensated elastically-hinged load cell with high-precision deflection measurement. The specimen deformation measurement, compensated for drift through image tracking, yields displacement reproducibility of <6 nm. Proof of principle tensile experiments are performed on 5 µm-thick aluminum-alloy thin film specimens, demonstrating reproducible Young’s modulus measurement of 72.6 ± 3.7 GPa. Room temperature creep experiments show excellent stability of the force measurement and underline the methodology’s high reproducibility and suitability for time-dependent nano-force tensile testing of on-wafer specimens.

  19. NGNP Graphite Selection and Acquisition Strategy

    SciTech Connect

    Burchell, T.; Bratton, R.; Windes, W.

    2007-09-30

    The nuclear graphite (H-451) previously used in the United States for High-Temperature Reactors (HTRs) is no longer available. New graphites have been developed and are considered suitable candidates for the Next-Generation Nuclear Plant (NGNP). A complete properties database for these new, available, candidate grades of graphite must be developed to support the design and licensing of NGNP core components. Data are required for the physical, mechanical (including radiation-induced creep), and oxidation properties of graphites. Moreover, the data must be statistically sound and take account of in-billet, between billets, and lot-to-lot variations of properties. These data are needed to support the ongoing development1 of the risk-derived American Society of Mechanical Engineers (ASME) graphite design code (a consensus code being prepared under the jurisdiction of the ASME by gas-cooled reactor and NGNP stakeholders including the vendors). The earlier Fort St. Vrain design of High-Temperature Reactor (HTRs) used deterministic performance models for H-451, while the NGNP will use new graphite grades and risk-derived (probabilistic) performance models and design codes, such as that being developed by the ASME. A radiation effects database must be developed for the currently available graphite materials, and this requires a substantial graphite irradiation program. The graphite Technology Development Plan (TDP)2 describes the data needed and the experiments planned to acquire these data in a timely fashion to support NGNP design, construction, and licensing. The strategy for the selection of appropriate grades of graphite for the NGNP is discussed here. The final selection of graphite grades depends upon the chosen reactor type and vendor because the reactor type (pebble bed or prismatic block) has a major influence on the graphite chosen by the designer. However, the time required to obtain the needed irradiation data for the selected NGNP graphite is sufficiently

  20. Analysis of Factors Influencing Measurement Accuracy of Al Alloy Tensile Test Results

    NASA Astrophysics Data System (ADS)

    Podgornik, Bojan; Žužek, Borut; Sedlaček, Marko; Kevorkijan, Varužan; Hostej, Boris

    2016-02-01

    In order to properly use materials in design, a complete understanding of and information on their mechanical properties, such as yield and ultimate tensile strength must be obtained. Furthermore, as the design of automotive parts is constantly pushed toward higher limits, excessive measuring uncertainty can lead to unexpected premature failure of the component, thus requiring reliable determination of material properties with low uncertainty. The aim of the present work was to evaluate the effect of different metrology factors, including the number of tested samples, specimens machining and surface quality, specimens input diameter, type of testing and human error on the tensile test results and measurement uncertainty when performed on 2xxx series Al alloy. Results show that the most significant contribution to measurement uncertainty comes from the number of samples tested, which can even exceed 1 %. Furthermore, moving from experimental laboratory conditions to very intense industrial environment further amplifies measurement uncertainty, where even if using automated systems human error cannot be neglected.

  1. Nano-Scale Tensile Testing and Sample Preparation Techniques for Silicon Nanowires

    NASA Astrophysics Data System (ADS)

    Fujii, Tatsuya; Sudoh, Koichi; Sakakihara, Shouichi; Naito, Muneyuki; Inoue, Shozo; Namazu, Takahiro

    2013-11-01

    In this paper, we describe an experimental technique to achieve a highly reliable characterization of the mechanical properties of silicon (Si) nanowires (NWs). A reusable on-chip Si device consisting of comb-drive electrostatic actuator for generating tensile force and capacitive sensors for measuring tensile force and displacement was designed and developed for quasi-static tensile test of Si NWs. The combination of focused ion beam (FIB) fabrication, FIB-assisted chemical vapor deposition, and probe manipulation enabled us to directly fabricate the NWs on the device. This sampling technique led to high yielding percentage of nano-scale tensile testing. The NWs were made from 200-nm-thick Si membranes that were produced by using silicon-on-nothing membrane fabrication technique. Several Si NWs were annealed at 700 °C in ultrahigh vacuum (UHV) for 5 min in order to examine the influence of annealing on the mechanical characteristics. The mean Young's modulus for nonannealed NWs was 129.1+/-10.1 GPa. After UHV annealing, the mean value was improved to be 168.1+/-1.3 GPa, comparable to the ideal value for Si(001)[110]. The annealing process gave rise to improving the Young's modulus, whereas it degraded the strength. Transmission electron microscopy suggested that recrystallization and gallium nanoclusters formation by annealing would have changed the mechanical characteristics.

  2. Ten deg off-axis tensile test for intralaminar shear characterization of fiber composites

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Sinclair, J. H.

    1976-01-01

    A combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the intralaminar shear characterization of unidirectional composites. Composite mechanics, a combined-stress failure criterion, and a finite element analysis were used to determine theoretically the stress-strain variation across the specimen width and the relative stress and strain magnitudes at the 10 deg plane. Strain gages were used to measure the strain variation across the specimen width at specimen midlength and near the end tabs. Specimens from Mod-I/epoxy, T-300/epoxy, and S-glass/epoxy were used in the experimental program. It was found that the 10 deg off-axis tensile test specimen is suitable for intralaminar shear characterization and it is recommended that it should be considered as a possible standard test specimen for such a characterization.

  3. NGNP – Creating Validated TRL and TDRMs for Critical Systems, Subsystems, and Components

    SciTech Connect

    John W. Collins; John M. Beck; Emmanuel O. Opare; Layne F. Pincock

    2008-09-01

    This report introduces two draft Next Generation Nuclear Plant (NGNP) Technology Development Roadmaps (TDRMs) and documents the methods used to create them. As such, this report depicts the development of the hardware needed to successfully operate the NGNP and identifies this hardware by the area of the plant it supports and by system, subsystem, and component (SSC). Several options exist for which technologies are selected to fulfill the functions of the NGNP. These options are represented by differing SSCs and are grouped into reference designs. Each SSC associated with each reference design is evaluated, rated, and assigned a technology readiness level (TRL). A rollup of the TRLs allows for comparison of the various reference designs. A TDRM then documents the tasks needed to obtain information in key discriminating criteria to support technology down selection and the tasks and test required to sufficiently mature the technology and reduce the likelihood of technological failure upon installation. This report presents the path forward, methods, and tools used to understand the requirements, manage the uncertainty, and mitigate the risk for the NGNP project. The key tool, TDRMs, is the means to facilitate NGNP risk-informed decision making, technology down selection, and technology qualification and maturation while serving to coordinate engineering, research and development, and licensing efforts.

  4. NGNP Risk Management through Assessing Technology Readiness

    SciTech Connect

    John W. Collins

    2010-08-01

    Throughout the Next Generation Nuclear Plant (NGNP) project life cycle, technical risks are identified, analyzed, and mitigated and decisions are made regarding the design and selection of plant and sub-system configurations, components and their fabrication materials, and operating conditions. Risk resolution and decision making are key elements that help achieve project completion within budget and schedule constraints and desired plant availability. To achieve this objective, a formal decision-making and risk management process was developed for NGNP, based on proven systems engineering principles that have guided aerospace and military applications.

  5. The effectiveness of combined gripping method in tensile testing of UHMWPE single yarn

    NASA Astrophysics Data System (ADS)

    Wang, H. X.; Hazell, P. J.; Shankar, K.; Morozov, E. V.; Escobedo, J. P.

    2015-07-01

    This paper presents the experimental study on the effectiveness of combined gripping method employed in the tensile testing of UHMWPE (Dyneema® SK75) single yarn. Seven different solutions including epoxy, acrylic, and ethyl cyanoacrylate adhesives were tested under quasi-static loadings in order to determine the most effective adhesive for bonding UHMWPE single yarn to aluminium sheets. The ethyl cyanoacrylate adhesive combined with polyolefin surface primer was found to be the best choice which could prevent yarn slippage and ensure the failure of yarn occurs in the gauge section. The single yarns were then tested at three strain rates of 3.3×10-5, 3.3×10-3, and 0.33 s-1. The tensile strength, maximum strain, and Young's modulus were determined from the measured stress-strain curves and compared with the values from literature; the results showed these tensile properties of single yarn depend on strain rate over the range tested.

  6. Microstructure and fracture behavior of F82H steel under different irradiation and tensile test conditions

    NASA Astrophysics Data System (ADS)

    Wang, K.; Dai, Y.; Spätig, P.

    2016-01-01

    Specimens of martensitic steel F82H were irradiated to doses ranging from 10.7 dpa/850 appm He to 19.6 dpa/1740 appm He at temperatures between 165 and 305 °C in the second experiment of SINQ Target Irradiation Program (STIP-II). Tensile tests were conducted at different temperatures and various fracture modes were observed. Microstructural changes including irradiation-induced defect clusters, dislocation loops and helium bubbles under different irradiation conditions were investigated using transmission electron microscopy (TEM). The deformation microstructures of tensile tested specimens were carefully examined to understand the underlying deformation mechanisms. Deformation twinning was for the first time observed in irradiated martensitic steels. A change of deformation mechanism from dislocation channeling to deformation twinning was observed when the fracture mode changed from rather ductile (quasi-cleavage) to brittle (intergranular or cleavage and intergranular mixed).

  7. A novel strategy for utilizing voice coil servoactuators in tensile tests of low volume protein hydrogels

    PubMed Central

    Saqlain, Farees; Popa, Ionel; Fernández, Julio M.; Alegre-Cebollada, Jorge

    2015-01-01

    We present a novel tensile testing system optimized for the mechanical loading of microliter volume protein hydrogels. Our apparatus incorporates a voice coil servoactuator capable of carrying out fixed velocity extension-relaxation cycles as well as extension step protocols. The setup is equipped with an acrylic cuvette permitting day-long incubations in solution. To demonstrate the functionality of the device, we photochemically crosslinked polyproteins of the I91 immunoglobulin domain from the muscle protein titin to create solid hydrogels that recapitulate elastic properties of muscle. We present data from tensile tests of these low volume biomaterials that support protein unfolding as a main determinant of the elasticity of protein hydrogels. Our results demonstrate the potential use of protein hydrogels as biomaterials whose elastic properties dynamically respond to their environment. PMID:25960689

  8. Tensile test of pressureless-sintered silicon nitride at elevated temperature

    NASA Technical Reports Server (NTRS)

    Matsusue, K.; Fujisawa, Y.; Takahara, K.

    1985-01-01

    Uniaxial tensile strength tests of pressureless sintered silicon nitride were carried out in air at temperatures ranging from room temperature up to 1600 C. Silicon nitrides containing Y2O3, Al2O3, Al2O3-MgO, or MgO-CeO2 additives were tested. The results show that the composition of the additive used influences the strength characteristics of the silicon nitride. The tensile strength rapidly decreased at temperatures above 1000 C for the materials containing MgO as the additive and above 1000 C for the material with Y2O3. When the temperature increased to as high as 1300 C, the strength decreased to about 10 percent of the room temperature strength in each case. Observations of the fracture origin and of the crack propagation on the fracture surfaces are discussed.

  9. Adhesion Assessment of Bnt Films on Titanium Substrates Using a Tensile Test

    NASA Astrophysics Data System (ADS)

    Xu, Fangchao; Kusukawa, Kazuhiro

    Lead-free piezoelectric (Bi1/2Na1/2)TiO3 (abbreviated as BNT) films were deposited on 1 mm thick pure titanium(Ti) substrates by a hydrothermal method. Tensile tests were performed to quantitatively assess the adhesion strength between BNT films and Ti substrates. Ti substrates were pretreated by chemical polish and mechanical polish respectively prior to BNT film deposition. In the tensile test, the behavior of BNT film exfoliation was investigated by the replica method. The critical Ti substrate strain inducing BNT film exfoliation was determined by the aid of finite element analysis (FEM). In this study, the results revealed that BNT film exfoliations were caused by the strain of Ti substrate, and the mechanical polish pretreatment improved the adhesion of BNT film to Ti substrate.

  10. Effects of reclaimed asphalt pavement on indirect tensile strength test of foamed asphalt mix tested in dry condition

    NASA Astrophysics Data System (ADS)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    Indirect tensile strength (ITS) test was conducted to analyse strength of the foamed asphalt mixes incorporating reclaimed asphalt pavement. Samples were tested for ITS after cured in the oven at 40°C for 72 hours. This testing condition known as dry condition or unconditioned. Laboratory results show that reclaimed asphalt pavement (RAP) contents insignificantly affect the ITS results. ITS results significantly affected by foamed bitumen contents.

  11. Microtensile and tensile bond strength of single-bottle adhesives: a new test method.

    PubMed

    Abdalla, A I

    2004-04-01

    To evaluate the tensile and microtensile bond strength of five single-bottle adhesives to dentine, extracted human molar teeth were used. For each tooth dentine was exposed on the occlusal surface by cutting with an isomet saw and the remaining part was mounted in a plastic ring using dental stone. The tested adhesive materials were: Scotchbond 1, Syntac SC, One-Step, Prime & Bond 2.1 and Clearfil SE Bond. The adhesive was applied to either 1 mm(2) of dentine or a circular area with a diameter of 3.9 mm. Composite resin Clearfil AP-X was placed to the adhesives using a Teflon split mould 3.9 mm in diameter and 2.5 mm in height. Tensile and microtensile bond strengths were measured using a universal testing machine at a crosshead speed of 0.5 mm min(-1). Under tensile mode, the bond strengths were 16.7 +/- 3.5, 15.2 +/- 2.5, 11.5 +/- 3.2, 13.7 +/- 2.6, 20.9 +/- 4.2 MPa for each material. Under microtensile mode, the bond strengths were 52.5 +/- 9.5, 55.3 +/- 8.3, 40.5 +/- 5.2, 37.5 +/- 8.7, 60 +/- 6.21 MPa. Fracture pattern of bonded specimens showed 66% cohesive dentine failure in samples tested for tensile bond strength. For the microtensile test, failures were mainly adhesive at the interface between adhesive and dentine (94%). PMID:15089946

  12. A Constitutive Model of 6111-T4 Aluminum Alloy Sheet Based on the Warm Tensile Test

    NASA Astrophysics Data System (ADS)

    Hua, Lin; Meng, Fanzhi; Song, Yanli; Liu, Jianing; Qin, Xunpeng; Suo, Lianbing

    2014-03-01

    As main light-weight material, aluminum alloy sheets have been widely applied to produce auto body panels. In order to predict the formability and springback of aluminum alloy sheets, a precise constitutive model is a necessity. In this article, a series of warm tensile tests were conducted on Gleeble-1500D thermal mechanical simulator for 6111-T4 aluminum alloy sheets. The corresponding strain rate ranged from 0.015 to 1.5 s-1, and the temperature ranged from 25 to 350 °C. The relationship between the temperature, the strain rate, and the flow stress were discussed. A constitutive model based on the updated Fields-Backofen equation was established to describe the flow behavior of 6111-T4 aluminum alloy during the warm tensile tests. Subsequently, the average absolute relative error (AARE) was introduced to verify the predictability of the constitutive model. The value of AARE at the uniform plastic deformation stage was calculated to be 1.677%, which demonstrates that the predicted flow stress values were in accordance with the experimental ones. The constitutive model was validated by the fact that the simulated results of the warm tensile tests coincided with the experimental ones.

  13. NGNP Reactor Coolant Chemistry Control Study

    SciTech Connect

    Brian Castle

    2010-11-01

    The main focus of this paper is to identify the most desirable ranges of impurity levels in the primary coolant to optimize component life in the primary circuit of the Next Generation Nuclear Plant (NGNP), which will either be a prismatic block or pebble bed reactor.

  14. Assessment of NGNP Moisture Ingress Events

    SciTech Connect

    Bill Landman

    2011-04-01

    An assessment of modular HTGR moisture ingress events, making use of a phenomena identification and ranking process, was conducted by a panel of experts in the related areas for the U.S. next generation nuclear plant (NGNP) design. Consideration was given mainly to the prismatic core gas-cooled reactor configurations incorporating a steam generator within the primary circuit.

  15. Tensile-shear correlations obtained from shear punch test technique using a modified experimental approach

    NASA Astrophysics Data System (ADS)

    Karthik, V.; Visweswaran, P.; Vijayraghavan, A.; Kasiviswanathan, K. V.; Raj, Baldev

    2009-09-01

    Shear punch testing has been a very useful technique for evaluating mechanical properties of irradiated alloys using a very small volume of material. The load-displacement data is influenced by the compliance of the fixture components. This paper describes a modified experimental approach where the compliances of the punch and die components are eliminated. The analysis of the load-displacement data using the modified setup for various alloys like low carbon steel, SS316, modified 9Cr-1Mo, 2.25Cr-1Mo indicate that the shear yield strength evaluated at 0.2% offset of normalized displacement relates to the tensile YS as per the Von Mises yield relation ( σys = 1.73 τys). A universal correlation of type UTS = mτmax where m is a function of strain hardening exponent, is seen to be obeyed for all the materials in this study. The use of analytical models developed for blanking process are explored for evaluating strain hardening exponent from the load-displacement data. This study is directed towards rationalizing the tensile-shear empirical correlations for a more reliable prediction of tensile properties from shear punch tests.

  16. NRC Licensing Status Summary Report for NGNP

    SciTech Connect

    Moe, Wayne Leland; Kinsey, James Carl

    2014-11-01

    The Next Generation Nuclear Plant (NGNP) Project, initiated at Idaho National Laboratory (INL) by the U.S. Department of Energy (DOE) pursuant to provisions of the Energy Policy Act of 2005, is based on research and development activities supported by the Department of Energy Generation IV Nuclear Energy Systems Initiative. The principal objective of the NGNP Project is to support commercialization of high temperature gas-cooled reactor (HTGR) technology. The HTGR is a helium-cooled and graphite moderated reactor that can operate at temperatures much higher than those of conventional light water reactor (LWR) technologies. The NGNP will be licensed for construction and operation by the Nuclear Regulatory Commission (NRC). However, not all elements of current regulations (and their related implementation guidance) can be applied to HTGR technology at this time. Certain policies established during past LWR licensing actions must be realigned to properly accommodate advanced HTGR technology. A strategy for licensing HTGR technology was developed and executed through the cooperative effort of DOE and the NRC through the NGNP Project. The purpose of this report is to provide a snapshot of the current status of the still evolving pre-license application regulatory framework relative to commercial HTGR technology deployment in the U.S. The following discussion focuses on (1) describing what has been accomplished by the NGNP Project up to the time of this report, and (2) providing observations and recommendations concerning actions that remain to be accomplished to enable the safe and timely licensing of a commercial HTGR facility in the U.S.

  17. Investigation on thermoformability of PLA by rheological and hot tensile tests

    NASA Astrophysics Data System (ADS)

    Garofalo, Emilia; Iannaccone, Giovanni; Scarfato, Paola; Di Maio, Luciano; Incarnato, Loredana

    2012-07-01

    In this work the correlation between the thermoformability of different grades of polylactide acid (PLA 4032D, PLA 4042D and PLA 2003D) and their mechanical, thermal, and rheological properties was explored. In particular, hot tensile tests, at different stretching temperatures and crosshead speeds, were performed in order to identify an optimum windows of temperature and strain rate for improved thermoforming performance. The properties measured from the creep experiments were correlated with the propensity of PLA sheet to sag, while the unrecovered strains by the creep recovery tests were associated to mold replication attitude of the materials investigated.

  18. Tensile properties of nicalon fiber-reinforced carbon following aerospace turbine engine testing

    NASA Astrophysics Data System (ADS)

    Pierce, J. L.; Zawada, L. P.; Srinivasan, R.

    2003-06-01

    The durability of coated Nicalon silicon carbide fiber-reinforced carbon (SiC/C) as the flap and seal exhaust nozzle components in a military aerospace turbine engine was studied. Test specimens machined from both a flap and a seal component were tested for residual strength following extended ground engine testing on a General Electric F414 afterburning turbofan engine. Although small amounts of damage to the protective exterior coating were identified on each component following engine testing, the tensile strengths were equal to the as-fabricated tensile strength of the material. Differences in strength between the two components and variability within the data sets could be traced back to the fabrication process using witness coupon test data from the manufacturer. It was also observed that test specimens machined transversely across the flap and seal components were stronger than those machined along the length. The excellent retained strength of the coated SiC/C material after extended exposure to the severe environment in the afterburner exhaust section of an aerospace turbofan engine has resulted in this material being selected as the baseline material for the F414 exhaust nozzle system.

  19. Tensile, creep, and ABI tests on sn5%sb solder for mechanical property evaluation

    NASA Astrophysics Data System (ADS)

    Murty, K. Linga; Haggag, Fahmy M.; Mahidhara, Rao K.

    1997-07-01

    Sn5%Sb is one of the materials considered for replacing lead containing alloys for soldering in electronic packaging. We evaluated the tensile properties of the bulk material at varied strain-rates and temperatures (to 473K) to determine the underlying deformation mechanisms. Stress exponents of about three and seven were observed at low and high stresses, respectively, and very low activation energies for creep (about 16.7 and 37.7 kJ/mole) were noted. A maximum ductility of about 350% was noted at ambient temperature. Creep tests performed in the same temperature regime also showed two distinct regions, albeit with slightly different exponents (three and five) and activation energy (about 54.4 kJ/mole). Ball indentation tests were performed on the shoulder portions of the creep samples (prior to creep tests) using a Stress-Strain Microprobe@ (Advanced Technology Corporation) at varied indentation rates (strain-rates). The automated ball indentation (ABI) data were at relatively high strain-rates; however, they were in excellent agreement with creep data, while both these results deviated from the tensile test data. Work is planned to perform creep at high stresses at ambient and extend ABI tests to elevated temperatures.

  20. Orthodontic brackets removal under shear and tensile bond strength resistance tests - a comparative test between light sources

    NASA Astrophysics Data System (ADS)

    Silva, P. C. G.; Porto-Neto, S. T.; Lizarelli, R. F. Z.; Bagnato, V. S.

    2008-03-01

    We have investigated if a new LEDs system has enough efficient energy to promote efficient shear and tensile bonding strength resistance under standardized tests. LEDs 470 ± 10 nm can be used to photocure composite during bracket fixation. Advantages considering resistance to tensile and shear bonding strength when these systems were used are necessary to justify their clinical use. Forty eight human extracted premolars teeth and two light sources were selected, one halogen lamp and a LEDs system. Brackets for premolar were bonded through composite resin. Samples were submitted to standardized tests. A comparison between used sources under shear bonding strength test, obtained similar results; however, tensile bonding test showed distinct results: a statistical difference at a level of 1% between exposure times (40 and 60 seconds) and even to an interaction between light source and exposure time. The best result was obtained with halogen lamp use by 60 seconds, even during re-bonding; however LEDs system can be used for bonding and re-bonding brackets if power density could be increased.

  1. Infarcted rat myocardium: Data from biaxial tensile and uniaxial compressive testing and analysis of collagen fibre orientation.

    PubMed

    Sirry, Mazin S; Butler, J Ryan; Patnaik, Sourav S; Brazile, Bryn; Bertucci, Robbin; Claude, Andrew; McLaughlin, Ron; Davies, Neil H; Liao, Jun; Franz, Thomas

    2016-09-01

    Myocardial infarction was experimentally induced in rat hearts and harvested immediately, 7, 14 and 28 days after the infarction induction. Anterior wall infarct samples underwent biaxial tensile and uniaxial compressive testing. Orientation of collagen fibres was analysed following mechanical testing. In this paper, we present the tensile and compressive stress-strain raw data, the calculated tensile and compressive moduli and the measured angles of collagen orientation. The presented data is associated with the research article titled "Characterisation of the mechanical properties of infarcted myocardium in the rat under biaxial tension and uniaxial compression" (Sirry et al., 2016) [1]. PMID:27579338

  2. Self-Healing Nanofiber-Reinforced Polymer Composites. 1. Tensile Testing and Recovery of Mechanical Properties.

    PubMed

    Lee, Min Wook; An, Seongpil; Jo, Hong Seok; Yoon, Sam S; Yarin, Alexander L

    2015-09-01

    The present work aims at development of self-healing materials capable of partially restoring their mechanical properties under the conditions of prolonged periodic loading and unloading, which is characteristic, for example, of aerospace applications. Composite materials used in these and many other applications frequently reveal multiple defects stemming from their original inhomogeneity, which facilitates microcracking and delamination at ply interfaces. Self-healing nanofiber mats may effectively prevent such damage without compromising material integrity. Two types of core-shell nanofibers were simultaneously electrospun onto the same substrate in order to form a mutually entangled mat. The first type of core-shell fibers consisted of resin monomer (dimethylsiloxane) within the core and polyacrylonitrile within the shell. The second type of core-shell nanofibers consisted of cure (dimethyl-methyl hydrogen-siloxane) within the core and polyacrylonitrile within the shell. These mutually entangled nanofiber mats were used for tensile testing, and they were also encased in polydimethylsiloxane to form composites that were also subsequently subjected to tensile testing. During tensile tests, the nanofibers can be damaged in stretching up to the plastic regime of deformation. Then, the resin monomer and cure was released from the cores and the polydimethylsiloxane resin was polymerized, which might be expected to result in the self-healing properties of these materials. To reveal and evaluate the self-healing properties of the polyacrylonitrile-resin-cure nanofiber mats and their composites, the results were compared to the tensile test results of the monolithic polyacrylonitrile nanofiber mats or composites formed by encasing polyacrylonitrile nanofibers in a polydimethylsiloxane matrix. The latter do not possess self-healing properties, and indeed, do not recover their mechanical characteristics, in contrast to the polyacrylonitrile-resin-cure nanofiber mats and

  3. Lamb wave ultrasonic evaluation of welded AA2024 specimens at tensile static and fatigue testing

    NASA Astrophysics Data System (ADS)

    Burkov, M. V.; Byakov, A. V.; Shah, R. T.; Lyubutin, P. S.; Panin, S. V.

    2015-10-01

    The paper deals with the investigation of Lamb waves ultrasonic testing technique applied for evaluation of different stress-strain and damaged state of aluminum specimens at static and fatigue loading in order to develop a Structural Health Monitoring (SHM) approach. The experimental results of tensile testing of AA2024T3 specimens with welded joints are presented. Piezoelectric transducers used as actuators and sensors were adhesively bonded to the specimen's surface using two component epoxy. The set of static and cyclic tensile tests with two frequencies of acoustic testing (50 kHz and 335 kHz) were performed. The recorded signals were processed to calculate the maximum envelope in order to evaluate the changes of the stress-strain state of the specimen and its microstructure during static tension. The registered data are analyzed and discussed in terms of signal attenuation due to the formation of fatigue defects during cyclic loading. Understanding the relations between acoustic signal features and fatigue damages will provide us the ability to determine the damage state of the structure and its residual lifetime in order to design a robust SHM system.

  4. Localized strain measurements of the intervertebral disc annulus during biaxial tensile testing.

    PubMed

    Karakolis, Thomas; Callaghan, Jack P

    2015-01-01

    Both inter-lamellar and intra-lamellar failures of the annulus have been described as potential modes of disc herniation. Attempts to characterize initial lamellar failure of the annulus have involved tensile testing of small tissue samples. The purpose of this study was to evaluate a method of measuring local surface strains through image analysis of a tensile test conducted on an isolated sample of annular tissue in order to enhance future studies of intervertebral disc failure. An annulus tissue sample was biaxial strained to 10%. High-resolution images captured the tissue surface throughout testing. Three test conditions were evaluated: submerged, non-submerged and marker. Surface strains were calculated for the two non-marker conditions based on motion of virtual tracking points. Tracking algorithm parameters (grid resolution and template size) were varied to determine the effect on estimated strains. Accuracy of point tracking was assessed through a comparison of the non-marker conditions to a condition involving markers placed on tissue surface. Grid resolution had a larger effect on local strain than template size. Average local strain error ranged from 3% to 9.25% and 0.1% to 2.0%, for the non-submerged and submerged conditions, respectively. Local strain estimation has a relatively high potential for error. Submerging the tissue provided superior strain estimates. PMID:25145810

  5. NGNP Composites R&D Technical Issues Study

    SciTech Connect

    AREVA Federal Services

    2008-09-01

    This study identifies potential applications and design requirements for ceramic materials (CMs) and ceramic composite materials (CCMs) in the NGNP hightemperature gas-cooled reactor (HTGR) primary circuit. Components anticipated for fabrication from non-graphite CMs and CCMs are identified along with recommended normal and off-normal operating conditions. The evaluation defines required dimensions and material properties of the candidate materials for normal operating conditions (NOC), anticipated transients, abnormal events, and design basis events. The report also identifies additional activities required for codifying the selected materials. The activities include ASTM Standard and ASME Code development and other work to support NRC licensing of the plant. Evaluation of the NGNP baseline design indicates components requiring either CMs or CCMs depend upon the reactor operating temperatures. For a reactor outlet temperature of 900 oC, four of the five evaluated components would benefit from either CMs or CCMs. Although some thermal and mechanical data exist for most of the candidate materials, they all need additional irradiation, thermal, and mechanical testing. The codification process must take into account the type of material and the geometry of components using either CMs or CCMs. The process requires close integration of the design and the research and development (R&D) program, which has already started by using preliminary control rod component designs as the basis for establishing specimen geometry and test conditions. The remaining time and budget for completing the R&D program need further assessment.

  6. Characterization of the deformation texture after tensile test and cold rolling of a Ti-6Al-4V sheet alloy

    NASA Astrophysics Data System (ADS)

    Mehdi, B.; Azzeddine, H.; Badji, R.; Ji, V.; Alili, B.; Bradai, D.

    2015-04-01

    The deformation texture after cold rolling and tensile test of an industrial Ti-6Al-4V sheet alloy was studied using X-ray diffraction. The alloy was subjected to a cold rolling to different thickness reductions (from 20% to 60%) and then tensile tests have been carried out along three directions relatively to the rolling direction (0°, 45° and 90°). The experimental results were compared to the existing literature and discussed in terms of active plastic deformation mechanisms.

  7. Measurement of field-dependence elastic modulus of iron-gallium alloy using tensile test

    SciTech Connect

    Yoo, Jin-Hyeong; Flatau, Alison B.

    2005-05-15

    An experimental approach is used to identify Galfenol material properties under dc magnetic bias fields. Dog-bone-shaped specimens of single crystal Fe{sub 100-x}Ga{sub x}, where 18.6{<=}x{<=}33.2, underwent tensile testing along two crystallographic axis orientations, [110] and [100]. Young's modulus and Poisson's ratio sensitivity to magnetic fields and stoichiometry are investigated. Data are presented that demonstrate the dependence of these properties on applied magnetic-field levels and provide a substantial assessment of the trends in material properties for performance of alloys of different stoichiometries under varied operating conditions.

  8. Stiffness reductions during tensile fatigue testing of graphite/epoxy angle-ply laminates

    NASA Technical Reports Server (NTRS)

    Odom, E. M.; Adams, D. F.

    1982-01-01

    Tensile fatigue data was generated under carefully controlled test conditions. A computerized data acquisition system was used to permit the measurement of dynamic modulus without interrupting the fatigue cycling. Two different 8-ply laminate configurations, viz, + or - 45 (2s) and + or - 67.5 (2s), of a T300/5208 graphite/epoxy composite were tested. The + or - 45 (2s) laminate did exhibit some modulus decay, although there was no well-defined correlation with applied stress level or number of cycles. The + or - 67.5 (2s) laminate did not exhibit any measurable modulus decay. Secondary effects observed included a small but distinct difference between modulus as measured statically and dynamically, a slight recovery of the modulus decay after a test interruption, and a significant viscoelastic (creep) response of the + or - 45 (2s) laminate during fatigue testing.

  9. Design and construction of a tensile tester for the testing of simple composites

    NASA Technical Reports Server (NTRS)

    Borst, Mark A.; Spiegel, F. Xavier

    1994-01-01

    The following is a design for a tensile tester which will be used to test the tensile strength and anisotropic properties of simple composites. These simple composites are suspected to be anisotropic primarily in a single plane. When the composites undergo a tensile force, they will undergo deformation, causing movement either to the left or right. The composites are suspect due to their method of construction. Each sample has a single layer of unidirectional continuous fibers embedded in a rubbery resin. It has been well established that a serious limitation of unidirectional fiber composites is the very large in-plane anisotropy. The design presented here incorporates a single degree of freedom such that distortion (to the left or right) due to anisotropic tendencies may be measured. The device will spend the vast majority of its time in an undergraduate materials lab. As a result, ease of use and durability are valued more highly than research grade accuracy. Additional concerns focus on the fact that this machine will be built as a student project. Issues which are dealt with during this design include: specimen configuration or shape; a method of applying consistent, linear tension force; a method of gripping specimen without affecting its overall properties; a method of collecting data; repeatability of data; ease of use; ease of construction; and cost. After the device has been constructed, it will be used to test the simple composites which were fabricated in house. A comparison will be made between composites manufactured using aluminum screening as the strengthening fibers and those manufactured using fiberglass screening.

  10. Tensile and fatigue qualification testing of ITER-CS conduit alloy JK2LB

    NASA Astrophysics Data System (ADS)

    Walsh, R. P.; McRae, D. M.; Han, K.; Martovetsky, N. N.

    2015-12-01

    The ITER Central Solenoid (CS) coils utilize cable-in-conduit conductor (CICC) and the conduit alloy is JK2LB. The production grade conduit alloy (and it's welds) must meet strict requirements for strength, toughness, fatigue crack resistance, and fabricability. The conduit alloy must retain good mechanical properties after additional fabrication steps such as welding, coil winding strain and exposure to the Nb3Sn superconductor's reaction heat treatment. Here we present data from cryogenic tensile, fracture toughness, fatigue crack growth rate, and axial fatigue tests of JK2LB alloy and conduit butt welds, before and after the exposure to the reaction heat treatment. The tests of specimens removed directly from the conduit provide confirmation of the materials properties and the effect of the cold work and aging. The 4 K fatigue performance is extremely important to the reliability of the CS and is covered both by axial cyclic fatigue tests and the fatigue crack growth rate measurements.

  11. An investigation of tensile damage behavior of X5230/T800 polymer matrix composites through in-situ tensile testing in SEM

    SciTech Connect

    Zhang, S.J.; Zhang, H.Q.; Delale, F.; Liaw, B.M.; Bode, J.H.

    1994-12-31

    Dog bone tensile specimens made of 8-ply X5230/T800 polymer matrix composites with [0{degree}/+45{degree}/0{degree}/{minus}45{degree}]{sub s}, arrangement and 57% fiber volume fraction have been subjected to tensile loading either along or perpendicular to the 0{degree} fiber direction at various temperatures. The tests were conducted inside an enlarged specimen chamber of a Hitachi S-2400 scanning electron microscope (SEM). During the test, the upper surface of the specimen in the gage section area was closely monitored through the screen of the SEM and the images revealing the intermediate tensile damage events on the surface and the edge of the specimen were captured in-situ either by using a Polaroid camera or a thermal print processor. When loading was applied parallel to the 0{degree} fiber direction at room temperature, damage started in the 0{degree} ply in the form of fiber breaking, followed by multiple fiber braiding in the 0{degree} ply, delamination between O{degree} and {+-}45{degree} plies, matrix cracking along the fiber direction in the {+-}45{degree} plies and the eventual failure of the specimen. No matrix cracks in the 0{degree} ply were observed for tests in room temperature. However, when tested at 1OO C, interface cracks were found in the 0{degree} ply and the failure load decreases substantially. When the loading was applied perpendicular to the 0{degree} fiber direction, no damage was observed in the 0{degree} ply until failure. A finite element model which incorporates the observed damage progression and based on the microstructure of the composite was also developed.

  12. A comparative TEM study of in-reactor and post-irradiation tensile tested copper

    NASA Astrophysics Data System (ADS)

    Pakarinen, J.; Tähtinen, S.; Singh, B. N.

    2013-11-01

    The deformation microstructures of oxygen-free high-conductivity (OFHC) copper were examined by transmission electron microscopy (TEM) following in-reactor and post-irradiation slow strain rate tensile tests. The TEM results suggest that the main modes of deformation differ between all examined cases. Plastic deformation appeared predominantly localized in the defect-free cleared channels following post-irradiation testing and hardly any dislocations were seen outside the channels. The microstructures following in-reactor tests were characterized by a small amount of cleared channels and a distinct dislocation density within the matrix. However, the dislocations observed following in-reactor testing did not seem to interact with each other, whereas that was the main mode of deformation in the non-irradiated reference sample. The possible mechanisms of plastic deformation are discussed based on the experimental results. Dislocation-dislocation interactions played the major role if irradiation or irradiation damage is not present. As a result of the interactions, the microstructure of non-irradiated reference copper was characterized by a well-defined cellularized dislocation microstructure. Dynamic dislocation-displacement cascade interactions dominated the deformation process at the in-reactor tensile tests. As a result, the formation of defect-free cleared channels was delayed, dislocations were found from the matrix between the channels, and a clear strain hardening was observed after the yield point. No clear difference between accumulated irradiation damage at in-reactor and post-irradiation samples was found, which may be due to localized nature of SFT evolution in displacement cascades at copper. In the post-irradiation experiments, dislocations were confined to slip planes and annihilate irradiation defects, while moving on the planes and creating defect-free cleared channels. The plastic deformation is localized into these channels, causing a decrease in

  13. Validating Material Modelling of OFHC Copper Using Dynamic Tensile Extrusion (DTE) Test at Different Impact Velocity

    NASA Astrophysics Data System (ADS)

    Bonora, Nicola; Testa, Gabriel; Ruggiero, Andrew; Iannitti, Gianluca; Hörnqvist, Magnus; Mortazavi, Nooshin

    2015-06-01

    In the Dynamic Tensile Extrusion (DTE) test, the material is subjected to very large strain, high strain rate and elevated temperature. Numerical simulation, validated comparing with measurements obtained on soft-recovered extruded fragments, can be used to probe material response under such extreme conditions and to assess constitutive models. In this work, the results of a parametric investigation on the simulation of DTE test of annealed OFHC copper - at impact velocity ranging from 350 up to 420 m/s - using phenomenological and physically based models (Johnson-Cook, Zerilli-Armstrong and Rusinek-Klepaczko), are presented. Preliminary simulation of microstructure evolution was performed using crystal plasticity package CPFEM, providing, as input, the strain history obtained with FEM at selected locations along the extruded fragments. Results were compared with EBSD investigation.

  14. Baseline tensile tests of composite materials for LDEF (Long Duration Exposure Facility) exposure

    NASA Technical Reports Server (NTRS)

    Witte, William G.

    1987-01-01

    Tensile specimens of five graphite fiber reinforced composite materials were tested at room temperature to provide baseline data for similar specimens exposed to the space environment in low-Earth orbit on the NASA Long Duration Exposure Facility. All specimens were 4-ply (+ or - 45 deg)s layups; at least five replicate specimens were tested for each parameter evaluated. Three epoxy-matrix materials and two polysulfone-matrix materials, several fiber volume fractions, and two sizes of specimen were evaluated. Stress-strain and Poisson's ratio-stress curves, ultimate stress, strain at failure, secant modulus at 0.004 strain, inplane shear stress-strain curves, and unidirectional shear modulus at .004 shear strain are presented.

  15. Analysis of Sandwich Shells with Metallic Foam Cores based on the Uniaxial Tensile Test

    NASA Astrophysics Data System (ADS)

    Mata, H.; Santos, A.; Fernandes, A. A.; Valente, R. A. F.; Parente, M. P. L.; Jorge, R. Natal

    2011-05-01

    On this work, the authors present the development and evaluation of an innovative system able to perform reliable panels of sandwich sheets with metallic foam cores for industrial applications, especially in automotive and aeronautical industries. This work is divided into two parts; in the first part the mathematical model used to describe the behavior of sandwich shells with metal cores form is presented and some numerical examples are presented. In the second part of this work, the numerical results are validated using the experimental results obtained from the mechanical experiments. Using the isotropic hardening crushable foam constitutive model, available on ABAQUS, a set of different mechanical tests were simulated. The isotropic hardening model available uses a yield surface that is an ellipse centered at the origin in the p-q stress plane. Using this constitutive model, the uniaxial tensile test for this material was simulated, and a comparison with the experimental results was made.

  16. Multiscale stochastic simulations for tensile testing of nanotube-based macroscopic cables.

    PubMed

    Pugno, Nicola M; Bosia, Federico; Carpinteri, Alberto

    2008-08-01

    Thousands of multiscale stochastic simulations are carried out in order to perform the first in-silico tensile tests of carbon nanotube (CNT)-based macroscopic cables with varying length. The longest treated cable is the space-elevator megacable but more realistic shorter cables are also considered in this bottom-up investigation. Different sizes, shapes, and concentrations of defects are simulated, resulting in cable macrostrengths not larger than approximately 10 GPa, which is much smaller than the theoretical nanotube strength (approximately 100 GPa). No best-fit parameters are present in the multiscale simulations: the input at level 1 is directly estimated from nanotensile tests of CNTs, whereas its output is considered as the input for the level 2, and so on up to level 5, corresponding to the megacable. Thus, five hierarchical levels are used to span lengths from that of a single nanotube (approximately 100 nm) to that of the space-elevator megacable (approximately 100 Mm). PMID:18666164

  17. Tensile and burst tests in support of the cadmium safety rod failure evaluation

    SciTech Connect

    Thomas, J.K.

    1992-02-01

    The reactor safety rods may be subjected to high temperatures due to gamma heating after the core coolant level has dropped during the ECS phase of hypothetical LOCA event. Accordingly, an experimental safety rod testing subtask was established as part of a task to address the response of reactor core components to this accident. This report discusses confirmatory separate effects tests conducted to support the evaluation of failures observed in the safety rod thermal tests. As part of the failure evaluation, the potential for liquid metal embrittlement (LME) of the safety rod cladding by cadmium (Cd) -- aluminum (Al) solutions was examined. Based on the test conditions, literature data, and U-Bend tests, its was concluded that the SS304 safety rod cladding would not be subject to LME by liquid Cd-Al solutions under conditions relevant to the safety rod thermal tests or gamma heating accident. To confirm this conclusion, tensile tests on SS304 specimens were performed in both air and liquid Cd-Al solutions with the range of strain rates, temperatures, and loading conditions spanning the range relevant to the safety rod thermal tests and gamma heating accident.

  18. Modifications of system for elevated temperature tensile testing and stress-strain measurement of metal matrix composites

    SciTech Connect

    Diaz, J.O.

    1994-09-01

    Composites consisting of tungsten alloy wires in superalloy matrices are being studied because they offer the potential for increased strength compared to current materials used at temperatures up to a least 1093{degrees}C (2000{degrees}F). Previous research at the NASA Lewis Research Center and at other laboratories in the U.S., Europe, and Japan has demonstrated laboratory feasibility for fiber reinforced superalloys (FRS). The data for the mechanical and physical properties used to evaluate candidate materials is limited and a need exists for a more detailed and complete data base. The focus of this work was to develop a test procedure to provide a more complete FRS data base to quantitatively evaluate the composite`s potential for component applications. This paper will describe and discuss the equipment and procedures under development to obtain elevated temperature tensile stress-strain, strength and modulus data for the first generation of tungsten reinforced superalloy composite (TFRS) materials. Tensile stress-strain tests were conducted using a constant crosshead speed tensile testing machine and a modified load-strain measuring apparatus. Elevated temperature tensile tests were performed using a resistance wound commercial furnace capable of heating tests specimens up to 1093{degrees}C (2000{degrees}F). Tensile stress-strain data were obtained for hollow tubular stainless steel specimens serving as a prototype for future composite specimens.

  19. Modifications of system for elevated temperature tensile testing and stress-strain measurement of metal matrix composites

    NASA Technical Reports Server (NTRS)

    Diaz, J. O.

    1985-01-01

    Composites consisting of tungsten alloy wires in superalloy matrices are being studied because they offer the potential for increased strength compared to current materials used at temperatures up to at least 1093 C (2000F). Previous research at the NASA Lewis Research Center and at other laboratories in the U.S., Europe, and Japan has demonstrated laboratory feasibility for fiber reinforced superalloys (FRS). The data for the mechanical and physical properties used to evaluate candidate materials is limited and a need exists for a more detailed and complete data base. The focus of this work is to develop a test procedure to provide a more complete FRS data base to quantitatively evaluate the composite's potential for component applications. This paper will describe and discuss the equipment and procedures under development to obtain elevated temperature tensile stress-strain, strength and modulus data for the first generation of tungsten fiber reinforced superalloy composite (TFRS) materials. Tensile stress-strain tests are conducted using a constant crosshead speed tensile testing machine and a modified load-strain measuring apparatus. Elevated temperature tensile tests are performed using a resistance wound commercial furnace capable of heating test specimens up to 1093 C (2000 F). Tensile stress-strain data are obtained for hollow tubular stainless steel specimens serving as a prototype for future composite specimens.

  20. Mechanical properties of individual InAs nanowires studied by tensile tests

    SciTech Connect

    Li, X.; Wei, X. L. E-mail: qingchen@pku.edu.cn; Xu, T. T.; Ning, Z. Y.; Shu, J. P.; Chen, Q. E-mail: qingchen@pku.edu.cn; Wang, X. Y.; Pan, D.; Zhao, J. H.; Yang, T.

    2014-03-10

    Mechanical properties of individual InAs nanowires (NWs) synthesized by metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) methods are studied by in-situ tensile tests in a scanning electron microscope and their fracture strength and Young's modulus are obtained. The two types of NWs both exhibit brittle fracture with a maximum elastic strain up to ∼10%. Their fracture strength distributes in a similar range of ∼2–5 GPa with a general trend of increasing with NW volume decrease, which is well described by Weibull statistic with a smaller Weibull modulus and a higher characteristic strength for MOCVD NWs. Young's modulus is determined to be 16–78 GPa with an average value of 45 GPa and no dependence on NW diameter for MOCVD NWs and 34–79 GPa with an average value of 58 GPa for MBE NWs.

  1. Effects of segregated Cu on an Fe grain boundary by first-principles tensile tests.

    PubMed

    Yuasa, Motohiro; Mabuchi, Mamoru

    2010-12-22

    Cu is known as one of the harmful tramp elements in recycled Fe. In the present work, the effects of Cu on Fe grain boundary (GB) embrittlement have been investigated by first-principles tensile tests. Because the Fe-Cu bonds are rather isotropic and the effects due to their difference in atomic size are negligibly small, the GB atomic structure prior to straining is little changed by Cu segregation. However, the Fe-Fe bond around the Cu atom is weakened due to charge transfer from the Fe atom to the Cu atom, and premature bond breaking occurs at the weakened Fe-Fe bond, resulting in an enhancement of GB embrittlement by Cu segregation. The s and p electrons play a vital role in the charge transfer. PMID:21406808

  2. Analysis of Ninety Degree Flexure Tests for Characterization of Composite Transverse Tensile Strength

    NASA Technical Reports Server (NTRS)

    OBrien, T. Kevin; Krueger, Ronald

    2001-01-01

    Finite element (FE) analysis was performed on 3-point and 4-point bending test configurations of ninety degree oriented glass-epoxy and graphite-epoxy composite beams to identify deviations from beam theory predictions. Both linear and geometric non-linear analyses were performed using the ABAQUS finite element code. The 3-point and 4-point bending specimens were first modeled with two-dimensional elements. Three-dimensional finite element models were then performed for selected 4-point bending configurations to study the stress distribution across the width of the specimens and compare the results to the stresses computed from two-dimensional plane strain and plane stress analyses and the stresses from beam theory. Stresses for all configurations were analyzed at load levels corresponding to the measured transverse tensile strength of the material.

  3. An in situ tensile test apparatus for polymers in high pressure hydrogen

    NASA Astrophysics Data System (ADS)

    Alvine, K. J.; Kafentzis, T. A.; Pitman, S. G.; Johnson, K. I.; Skorski, D.; Tucker, J. C.; Roosendaal, T. J.; Dahl, M. E.

    2014-10-01

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex situ measurements of mechanical properties problematic. Designing in situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials such as Nd. Here we detail the design and operation of a solenoid based in situ tensile tester under high-pressure hydrogen environments up to 42 MPa (6000 psi). Modulus data from high-density polyethylene samples tested under high-pressure hydrogen at 35 MPa (5000 psi) are also reported as compared to baseline measurements taken in air.

  4. An In-situ Tensile Test Apparatus for Polymers in High Pressure Hydrogen

    SciTech Connect

    Alvine, Kyle J.; Kafentzis, Tyler A.; Pitman, Stan G.; Johnson, Kenneth I.; Skorski, Daniel C.; Tucker, Joseph C.; Roosendaal, Timothy J.; Dahl, Michael E.

    2014-10-10

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex-situ measurements of mechanical properties problematic. Designing in-situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials like Nd. Here we detail the design and operation of a solenoid based in-situ tensile tester under high-pressure hydrogen environments up to 5,000 psi. Modulus data from high-density polyethylene (HDPE) samples tested under high-pressure hydrogen are also reported as compared to baseline measurements taken in air.

  5. Directionally solidified lamellar eutectic superalloys by edge-defined, film-fed growth. [including tensile tests

    NASA Technical Reports Server (NTRS)

    Hurley, G. F.

    1975-01-01

    A program was performed to scale up the edge-defined, film-fed growth (EFG) method for the gamma/gamma prime-beta eutectic alloy of the nominal composition Ni-19.7 Cb - 6 Cr-2.5 Al. Procedures and problem areas are described. Flat bars approximately 12 x 1.7 x 200 mm were grown, mostly at speeds of 38 mm/hr, and tensile tests on these bars at 25 and 1000 C showed lower strength than expected. The feasibility of growing hollow airfoils was also demonstrated by growing bars over 200 mm long with a teardrop shaped cross-section, having a major dimension of 12 mm and a maximum width of 5 mm.

  6. An in situ tensile test apparatus for polymers in high pressure hydrogen

    SciTech Connect

    Alvine, K. J. Kafentzis, T. A.; Pitman, S. G.; Johnson, K. I.; Skorski, D.; Tucker, J. C.; Roosendaal, T. J.; Dahl, M. E.

    2014-10-15

    Degradation of material properties by high-pressure hydrogen is an important factor in determining the safety and reliability of materials used in high-pressure hydrogen storage and delivery. Hydrogen damage mechanisms have a time dependence that is linked to hydrogen outgassing after exposure to the hydrogen atmosphere that makes ex situ measurements of mechanical properties problematic. Designing in situ measurement instruments for high-pressure hydrogen is challenging due to known hydrogen incompatibility with many metals and standard high-power motor materials such as Nd. Here we detail the design and operation of a solenoid based in situ tensile tester under high-pressure hydrogen environments up to 42 MPa (6000 psi). Modulus data from high-density polyethylene samples tested under high-pressure hydrogen at 35 MPa (5000 psi) are also reported as compared to baseline measurements taken in air.

  7. Constitutive Modeling of the Dynamic-Tensile-Extrusion Test of PTFE

    NASA Astrophysics Data System (ADS)

    Resnyansky, Anatoly; Brown, Eric; Trujillo, Carl; Gray, George

    2015-06-01

    Use of polymers in the defence, aerospace and industrial application at extreme conditions makes prediction of behaviour of these materials very important. Crucial to this is knowledge of the physical damage response in association with the phase transformations during the loading and the ability to predict this via multi-phase simulation taking the thermodynamical non-equilibrium and strain rate sensitivity into account. The current work analyses Dynamic-Tensile-Extrusion (DTE) experiments on polytetrafluoroethylene (PTFE). In particular, the phase transition during the loading with subsequent tension are analysed using a two-phase rate sensitive material model implemented in the CTH hydrocode and the calculations are compared with experimental high-speed photography. The damage patterns and their link with the change of loading modes are analysed numerically and are correlated to the test observations.

  8. Mechanical properties of individual InAs nanowires studied by tensile tests

    NASA Astrophysics Data System (ADS)

    Li, X.; Wei, X. L.; Xu, T. T.; Ning, Z. Y.; Shu, J. P.; Wang, X. Y.; Pan, D.; Zhao, J. H.; Yang, T.; Chen, Q.

    2014-03-01

    Mechanical properties of individual InAs nanowires (NWs) synthesized by metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) methods are studied by in-situ tensile tests in a scanning electron microscope and their fracture strength and Young's modulus are obtained. The two types of NWs both exhibit brittle fracture with a maximum elastic strain up to ˜10%. Their fracture strength distributes in a similar range of ˜2-5 GPa with a general trend of increasing with NW volume decrease, which is well described by Weibull statistic with a smaller Weibull modulus and a higher characteristic strength for MOCVD NWs. Young's modulus is determined to be 16-78 GPa with an average value of 45 GPa and no dependence on NW diameter for MOCVD NWs and 34-79 GPa with an average value of 58 GPa for MBE NWs.

  9. Effects of segregated Cu on an Fe grain boundary by first-principles tensile tests

    NASA Astrophysics Data System (ADS)

    Yuasa, Motohiro; Mabuchi, Mamoru

    2010-12-01

    Cu is known as one of the harmful tramp elements in recycled Fe. In the present work, the effects of Cu on Fe grain boundary (GB) embrittlement have been investigated by first-principles tensile tests. Because the Fe-Cu bonds are rather isotropic and the effects due to their difference in atomic size are negligibly small, the GB atomic structure prior to straining is little changed by Cu segregation. However, the Fe-Fe bond around the Cu atom is weakened due to charge transfer from the Fe atom to the Cu atom, and premature bond breaking occurs at the weakened Fe-Fe bond, resulting in an enhancement of GB embrittlement by Cu segregation. The s and p electrons play a vital role in the charge transfer.

  10. Tensile Fracture Strength of Brisbane Tuff by Static and Cyclic Loading Tests

    NASA Astrophysics Data System (ADS)

    Erarslan, N.; Alehossein, H.; Williams, D. J.

    2014-07-01

    This research presents the results of laboratory experiments during the investigation of tensile strength-strain characteristics of Brisbane tuff disc specimens under static and diametral cyclic loading. Three different cyclic loading methods were used; namely, sinusoidal cyclic loading, type I and II increasing cyclic loading with various amplitude values. The first method applied the stress amplitude-cycle number (s-n) curve approach to the measurement of the indirect tensile strength (ITS) and fracture toughness ( K IC) values of rocks for the first time in the literature. The type I and II methods investigated the effect of increasing cyclic loading on the ITS and K IC of rocks. For Brisbane tuff, the reduction in ITS was found to be 30 % under sinusoidal loading, whereas type I and II increasing cyclic loading caused a maximum reduction in ITS of 36 %. The maximum reduction of the static K IC of 46 % was obtained for the highest amplitude type I cyclic loading tested. For sinusoidal cyclic loading, a maximum reduction of the static K IC of 30 % was obtained. A continuous irreversible accumulation of damage was observed in dynamic cyclic tests conducted at different amplitudes and mean stress levels. Scanning electron microscope images showed that fatigue damage in Brisbane tuff is strongly influenced by the failure of the matrix because of both inter-granular fracturing and trans-granular fracturing. The main characteristic was grain breakage under cyclic loading, which probably starts at points of contact between grains and is accompanied by the production of very small fragments, probably due to frictional sliding within the weak matrix.

  11. Discussion on FRP design properties based on flexural tests (ASTM D-790) and tensile tests (ASTM D-638)

    SciTech Connect

    Clark, J.M.

    1996-11-01

    Tensile and flexural test results on the same laminate can have significant difference with the reported flexural strength being up to 100% greater than the tensile strength using the standard ASTM reporting methods. Taken at face value, these results can lead to nonconservative designs. The flexural test method is much simpler and less expensive, but must be used with a clear understanding of how they were computed and with sound engineering judgment since the flexural strength is calculated with linear bending theory at failure loads that are usually in the nonlinear range. This is significant since the general accepted design practice is to use linear theory in the design of FRP equipment. Manufacturers reporting this value should thus have a clear understanding of the difference between the reported results for flexural strength and the required design strength. This paper shows how to determine the proper design value from a flexural test which results in safe designs of FRP equipment and shows that the reported flexural strength from the ASTM D-790 method should not be used in design of FRP equipment.

  12. Status of Initial Assessment of Physical and Mechanical Properties of Graphite Grades for NGNP Appkications

    SciTech Connect

    Strizak, Joe P; Burchell, Timothy D; Windes, Will

    2011-12-01

    Current candidate graphite grades for the core structures of NGNP include grades NBG-17, NBG-18, PCEA and IG-430. Both NBG-17 and NBG-18 are manufactured using pitch coke, and are vibrationally molded. These medium grain products are produced by SGL Carbon SAS (France). Tayo Tanso (Japan) produces IG-430 which is a petroleum coke, isostatically molded, nuclear grade graphite. And PCEA is a medium grain, extruded graphite produced by UCAR Carbon Co. (USA) from petroleum coke. An experimental program has been initiated to develop physical and mechanical properties data for these current candidate graphites. The results will be judged against the requirements for nuclear grade graphites set forth in ASTM standard D 7219-05 "Standard Specification for Isotropic and Near-isotropic Nuclear Graphites". Physical properties data including thermal conductivity and coefficient of thermal expansion, and mechanical properties data including tensile, compressive and flexural strengths will be obtained using the established test methods covered in D-7219 and ASTM C 781-02 "Standard Practice for Testing Graphite and Boronated Graphite Components for High-Temperature Gas-Cooled Nuclear Reactors". Various factors known to effect the properties of graphites will be investigated. These include specimen size, spatial location within a graphite billet, specimen orientation (ag and wg) within a billet, and billet-to-billet variations. The current status of the materials characterization program is reported herein. To date billets of the four graphite grades have been procured, and detailed cut up plans for obtaining the various specimens have been prepared. Particular attention has been given to the traceability of each specimen to its spatial location and orientation within a billet.

  13. Tensile Tests of Round-head, Flat-head, and Brazier-head Rivets

    NASA Technical Reports Server (NTRS)

    Schuette, Evan H; Bartone, Leonard M; Mandel, Merven W

    1944-01-01

    An investigation was conducted to determine the tensile strength of round-head (AN43C), flat-head(AN442), and brazier-head (AN4556) aluminum-alloy rivets because of the scarcity of information on the tensile strength of rivets. The results of the investigation are presented as curves that show the variation of the ratio of the tensile strength of the rivet to the tensile strength of the rivet crank with the ratio of the sheet thickness to the rivet diameter for the different types of rivet.

  14. NGNP Data Management and Analysis System Modeling Capabilities

    SciTech Connect

    Cynthia D. Gentillon

    2009-09-01

    Projects for the very-high-temperature reactor (VHTR) program provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. In addition, thermal-hydraulic experiments are conducted to validate codes used to assess reactor safety. The VHTR Program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are (1) qualified for use, (2) stored in a readily accessible electronic form, and (3) analyzed to extract useful results. This document focuses on the third NDMAS objective. It describes capabilities for displaying the data in meaningful ways and identifying relationships among the measured quantities that contribute to their understanding.

  15. NGNP Fuel Qualification White Paper

    SciTech Connect

    David A. Petti

    2010-07-01

    The Japanese high temperature gas reactor program is centered on the High Temperature Engineering Test Reactor (HTTR), which has a thermal power of 30 MW and 950°C maximum coolant outlet temperature. The HTTR achieved criticality in November 1998 and has undergone a series of rise-to-power tests [Fujikawa 2004]. In December 2001, an outlet temperature of 850°C was achieved and in April 2004 a temperature of 950°C was achieved. As of July 2004, the reactor had operated for 224 effective full power days (EFPD). The planned core life cycle is 660 EFPD [Verfondern 2000]. It is planned to couple a high temperature process heat application to the HTTR through its intermediate heat exchanger in the future.

  16. Fracture Testing with Surface Crack Specimens. [especially the residual tensile strength test

    NASA Technical Reports Server (NTRS)

    Orange, T. W.

    1974-01-01

    Recommendations are given for the design, preparation, and static fracture testing of surface crack specimens. The recommendations are preceded by background information including discussions of stress intensity factors, crack opening displacements, and fracture toughness values associated with surface crack specimens. Cyclic load and sustained load tests are discussed briefly.

  17. Tensile and compression testing of single-crystal gamma Ti-55.5Al

    SciTech Connect

    Zupan, M.; LaVan, D.; Hemker, K.J.

    1997-12-31

    Gamma based titanium aluminides are considered to be promising high temperature application alloys because of their exceptional high temperature mechanical properties and good oxidation resistance. Moreover, with a density less than half of current nickel based super alloys, the increased power to weight ratio that can be realized by using titanium aluminides is very attractive to the automotive and aircraft industries. Here the orientation and temperature dependence of the flow strength of {gamma}-TiAl is being measured to promote a fundamental understanding of the deformation mechanisms that are active in this alloy. High quality single crystals of {gamma}-Ti-55.5 Al have been grown using an optical float zone furnace, which allows for crystal seeding and provides a containerless growth environment. These crystals have been oriented using back reflection Laue and TEM and cut into microsample tensile specimens by electric discharge machining. The microsample testing technique developed at Johns Hopkins is being utilized to measure the orientation, temperature and tension/compression dependence of the flow strength of TiAl. An outline of the microsample testing techniques that have been developed for this study and preliminary results follow in this paper.

  18. Tensile Tests of NACA and Conventional Machine-countersunk Flush Rivets

    NASA Technical Reports Server (NTRS)

    Bartone, Leonard M.; Mandel, Merven W.

    1944-01-01

    An investigation was conducted to determine and compare the tensile strength of NACA and conventional machine-countersunk flush rivets of several rivet-head angles and varying countersunk depth. The results of the investigation are presented in the form of curves that show the variation of the tensile strength of the rivet with the ratio of the sheet thickness to the rivet diameter. For the same rivet-head angle and for a given angle of c/d, the NACA rivets developed higher tensile strength than the conventional rivets.

  19. Biaxial Tensile Test of Cold Rolled IF Steel Sheet for Large Plastic Strain Range

    NASA Astrophysics Data System (ADS)

    Enatsu, Ryotaro; Kuwabara, Toshihiko

    2011-08-01

    Deformation behavior of cold rolled IF steel sheet (SPCE) under biaxial tension has been investigated for large plastic strain range over 15%. The test material was bent and TIG welded to form a tubular specimen with an outer diameter of 46.2 mm and wall thickness of 0.8 mm. The tubular specimens have been subjected to linear stress paths in the first quadrant of stress space with the use of a servo-controlled tension-internal pressure testing machine developed by one of the authors [T. Kuwabara, K. Yoshida, K. Narihara, S. Takahashi, Anisotropic plastic deformation of extruded aluminum alloy tube under axial forces and internal pressure, Int. J. Plasticity 21, 101-117 (2005)]. Moreover, biaxial tensile tests using a cruciform specimen have also been carried out to more precisely measure the deformation behavior for a small strain range following initial yielding. True stress-true plastic strain curves, contours of plastic work in stress space and the directions of plastic strain rates have been measured and compared with those calculated using selected yield functions: the von Mises, Hill's quadratic and Yld2000-2d [Barlat, F., Brem, J.C., Yoon, J.W., Chung, K., Dick, R.E., Lege, D.J., Pourboghrat, F., Choi, S.H., Chu, E., Plane stress yield function for aluminum alloy sheets—Part 1: Theory. Int. J. Plasticity 19, 1297-1319 (2003)]. The plastic deformation behavior up to a work equivalent plastic strain of ɛ0p = 0.19 has been successfully measured. It is found that the test material exhibits differential hardening and that the Yld2000-2d yield function with an exponent of six most closely predicts the contours of plastic work and the directions of plastic strain rates.

  20. Mechanical properties of Bi2223 filaments extracted from multifilamentary tape evaluated by the single-fibre tensile test

    NASA Astrophysics Data System (ADS)

    Sugano, Michinaka; Osamura, Kozo; Hojo, Masaki

    2003-05-01

    The Young's modulus and the tensile fracture strength of Bi2223 filaments extracted from multifilamentary tape have been evaluated using the single-fibre tensile test; they are estimated to be 106 GPa and 45 MPa, respectively. The distribution of the fracture strength can be analysed using the Weibull distribution function. It was found that the observed scatter of strength is very large compared with other superconducting filaments such as NbTi and Nb3Al. The Young's modulus was nearly identical with the estimated values based on the rule of mixture from the unload/reload modulus.

  1. Cubical Mass-Spring Model design based on a tensile deformation test and nonlinear material model.

    PubMed

    San-Vicente, Gaizka; Aguinaga, Iker; Tomás Celigüeta, Juan

    2012-02-01

    Mass-Spring Models (MSMs) are used to simulate the mechanical behavior of deformable bodies such as soft tissues in medical applications. Although they are fast to compute, they lack accuracy and their design remains still a great challenge. The major difficulties in building realistic MSMs lie on the spring stiffness estimation and the topology identification. In this work, the mechanical behavior of MSMs under tensile loads is analyzed before studying the spring stiffness estimation. In particular, the performed qualitative and quantitative analysis of the behavior of cubical MSMs shows that they have a nonlinear response similar to hyperelastic material models. According to this behavior, a new method for spring stiffness estimation valid for linear and nonlinear material models is proposed. This method adjusts the stress-strain and compressibility curves to a given reference behavior. The accuracy of the MSMs designed with this method is tested taking as reference some soft-tissue simulations based on nonlinear Finite Element Method (FEM). The obtained results show that MSMs can be designed to realistically model the behavior of hyperelastic materials such as soft tissues and can become an interesting alternative to other approaches such as nonlinear FEM. PMID:22156291

  2. In-vitro tensile testing machine for vibration study of fresh rabbit Achilles tendon

    NASA Astrophysics Data System (ADS)

    Revel, Gian M.; Scalise, Alessandro; Scalise, Lorenzo; Pianosi, Antonella

    2001-10-01

    A lot of people, overall athletic one suffer from tendinitis or complete rupture of the Achilles tendon. This structure becomes inflamed and damaged mainly from a variety of mechanical forces and sometimes due to metabolic problems, such as diabetes or arthritis. Over the past three decades extensive studies have been performed on the structural and mechanical properties of Achilles tendon trying to explain the constitutive equations to describe and foresee tendon behavior. Among the various mechanical parameters, the vibrational behavior is also of interest. Several investigations are performed in order to study how the Achilles tendon vibrations influence the response of the muscle proprioception and human posture. The present article describes how in vitro tensile experiments can be performed, taking into account the need to simulate physiological condition of Achilles tendon and thus approaching some opened problems in the design of the experimental set-up. A new system for evaluating tendon vibrations by non contact techniques is proposed. Preliminary simple elongation tests are made extracting the main mechanical parameters: stress and strain at different fixed stretches, in order to characterize the tissue. Finally, a vibration study is made at each pretensioned tendon level evaluating the oscillating curves caused by a small hammer.

  3. Mechanical Properties of Polycrystalline Titanium Nitride Films Measured by XRD Tensile Testing

    NASA Astrophysics Data System (ADS)

    Namazu, Takahiro; Inoue, Shozo; Takemoto, Hideki; Koterazawa, Keiji

    This paper describes measurement of mechanical properties of micron-thin polycrystalline titanium nitride (TiN) films. We developed a novel tensile test technique that can directly measure lateral elastic strain of a microscale single/poly-crystalline specimen by means of X-ray diffraction (XRD), which enables evaluation of not only Young's modulus but also Poisson's ratio of TiN films. TiN films having thicknesses of 0.5 μm to 1.6 μm are deposited onto the top and bottom surfaces of a microscale single crystal silicon (Si) specimen. The deposition is carried out by r.f. reactive magnetron sputtering under Ar partial pressure ranging from 0.7 Pa to 1.0 Pa. Average values of Young's modulus and Poisson's ratio for the Si monolayer specimen are found to be 169 GPa and 0.35, respectively, which are in close agreement with analytical values. TiN films deposited under an Ar partial pressure of 0.7 Pa have average Young's modulus of 290 GPa and Poisson's ratio of 0.36. These values gradually decrease with increasing Ar partial pressure, but are independent of TiN film thickness. Fracture strength of a TiN/Si/TiN composite specimen shows dependence on film thickness, regardless of Ar partial pressure.

  4. Biaxial tensile tests identify epidermis and hypodermis as the main structural elements of sweet cherry skin

    PubMed Central

    Brüggenwirth, Martin; Fricke, Heiko; Knoche, Moritz

    2014-01-01

    The skin of developing soft and fleshy fruit is subjected to considerable growth stress, and failure of the skin is associated with impaired barrier properties in water transport and pathogen defence. The objectives were to establish a standardized, biaxial tensile test of the skin of soft and fleshy fruit and to use it to characterize and quantify mechanical properties of the sweet cherry (Prunus avium) fruit skin as a model. A segment of the exocarp (ES) comprising cuticle, epidermis, hypodermis and adhering flesh was mounted in the elastometer such that the in vivo strain was maintained. The ES was pressurized from the inner surface and the pressure and extent of associated bulging were recorded. Pressure : strain responses were almost linear up to the point of fracture, indicating that the modulus of elasticity was nearly constant. Abrading the cuticle decreased the fracture strain but had no effect on the fracture pressure. When pressure was held constant, bulging of the ES continued to increase. Strain relaxation upon releasing the pressure was complete and depended on time. Strains in longitudinal and latitudinal directions on the bulging ES did not differ significantly. Exocarp segments that released their in vivo strain before the test had higher fracture strains and lower moduli of elasticity. The results demonstrate that the cherry skin is isotropic in the tangential plane and exhibits elastic and viscoelastic behaviour. The epidermis and hypodermis, but not the cuticle, represent the structural ‘backbone’ in a cherry skin. This test is useful in quantifying the mechanical properties of soft and fleshy fruit of a range of species under standardized conditions. PMID:24876301

  5. Biaxial tensile tests identify epidermis and hypodermis as the main structural elements of sweet cherry skin.

    PubMed

    Brüggenwirth, Martin; Fricke, Heiko; Knoche, Moritz

    2014-01-01

    The skin of developing soft and fleshy fruit is subjected to considerable growth stress, and failure of the skin is associated with impaired barrier properties in water transport and pathogen defence. The objectives were to establish a standardized, biaxial tensile test of the skin of soft and fleshy fruit and to use it to characterize and quantify mechanical properties of the sweet cherry (Prunus avium) fruit skin as a model. A segment of the exocarp (ES) comprising cuticle, epidermis, hypodermis and adhering flesh was mounted in the elastometer such that the in vivo strain was maintained. The ES was pressurized from the inner surface and the pressure and extent of associated bulging were recorded. Pressure : strain responses were almost linear up to the point of fracture, indicating that the modulus of elasticity was nearly constant. Abrading the cuticle decreased the fracture strain but had no effect on the fracture pressure. When pressure was held constant, bulging of the ES continued to increase. Strain relaxation upon releasing the pressure was complete and depended on time. Strains in longitudinal and latitudinal directions on the bulging ES did not differ significantly. Exocarp segments that released their in vivo strain before the test had higher fracture strains and lower moduli of elasticity. The results demonstrate that the cherry skin is isotropic in the tangential plane and exhibits elastic and viscoelastic behaviour. The epidermis and hypodermis, but not the cuticle, represent the structural 'backbone' in a cherry skin. This test is useful in quantifying the mechanical properties of soft and fleshy fruit of a range of species under standardized conditions. PMID:24876301

  6. Slow Strain Rate Tensile Testing to Assess the Ability of Superalloys to Resist Environment-Assisted Intergranular Cracking

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Telesman, Jack; Banik, Anthony; McDevitt, Erin

    2014-01-01

    Intergranular fatigue crack initiation and growth due to environmental degradation, especially at notched features, can often limit the fatigue life of disk superalloys at high temperatures. For clear comparisons, the effects of alloy composition on cracking in air needs to be understood and compared separately from variables associated with notches and cracks such as effective stress concentration, plastic flow, stress relaxation, and stress redistribution. The objective of this study was to attempt using simple tensile tests of specimens with uniform gage sections to compare the effects of varied alloy composition on environment-assisted cracking of several powder metal and cast and wrought superalloys including ME3, LSHR, Udimet 720, ATI 718Plus alloy, Haynes 282, and Inconel 740. Slow and fast strain-rate tensile tests were found to be a useful tool to compare propensities for intergranular surface crack initiation and growth. The effects of composition and heat treatment on tensile fracture strain and associated failure modes were compared. Environment interactions were determined to often limit ductility, by promoting intergranular surface cracking. The response of various superalloys and heat treatments to slow strain rate tensile testing varied substantially, showing that composition and microstructure can significantly influence environmental resistance to cracking.

  7. An Evaluation of Some Current Practices for Short-Time Elevated-Temperature Tensile Tests of Metals

    NASA Technical Reports Server (NTRS)

    Manning, Charles R., Jr.; Heimerl, George J.

    1960-01-01

    The effect of different testing practices on the short-time elevated-temperature tensile properties was determined for 2024-T3 aluminum-alloy, HM21A-T8 and HK31A-H24 magnesium-alloy, and 12 MoV stainless-steel sheet. Tests were made under single strain-rate and single head-speed conditions. A dual strain-rate test was also included. An evaluation of the effects of these practices is given for the tensile and yield strengths, the elongation in 2 inches, and the uniform elongation. The need for a uniform testing practice is demonstrated. Recommended practices suggested by different organizations are included.

  8. Effect of Test Specimen Shape and Size on Interlaminar Tensile Properties of Advanced Carbon-Carbon Composites

    NASA Technical Reports Server (NTRS)

    Vaughn, Wallace L.

    2015-01-01

    The interlaminar tensile strength of 1000-tow T-300 fiber ACC-6 carbon-carbon composites was measured using the method of bonding the coupons to adherends at room temperature. The size, 0.70 to 1.963 inches maximum width or radius, and shape, round or square, of the test coupons were varied to determine if the test method was sensitive to these variables. Sixteen total variations were investigated and the results modeled.

  9. New Generation Nuclear Plant (NGNP) Project, Preliminary Point Design

    SciTech Connect

    F. H. Southworth; P. E. MacDonald; A. M. Baxter; P. D. Bayless; J. M. Bolin; H. D. Gougar; R. L. Moore; A. M. Ougouag; M. B. Richards; R. L. Sant; J. W. Sterbentz; W. K. Terry

    2004-03-01

    This paper provides a preliminary assessment of two possible versions of the Next Generation Nuclear Plant (NGNP), a prismatic fuel type helium gas-cooled reactor and a pebblebed fuel helium gas reactor. Both designs will meet the three basic requirements that have been set for the NGNP: a coolant outlet temperature of 1000 C, passive safety, and a total power output consistent with that expected for commercial high-temperature gas-cooled reactors.

  10. NGNP Process Heat Applications: Hydrogen Production Accomplishments for FY2010

    SciTech Connect

    Charles V Park

    2011-01-01

    This report summarizes FY10 accomplishments of the Next Generation Nuclear Plant (NGNP) Engineering Process Heat Applications group in support of hydrogen production technology development. This organization is responsible for systems needed to transfer high temperature heat from a high temperature gas-cooled reactor (HTGR) reactor (being developed by the INL NGNP Project) to electric power generation and to potential industrial applications including the production of hydrogen.

  11. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    NASA Technical Reports Server (NTRS)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  12. Development of a miniature tensile Kolsky bar for dynamic testing of thin films

    NASA Astrophysics Data System (ADS)

    Paul, Jastin V.

    Mechanical properties such as yield stress and ultimate strength are most commonly obtained under quasi-static (strain rate of 10--4 s--1) loading conditions Materials such as metals, ceramics, and polymers may exhibit significant changes in mechanical response when subjected to high strain rate (102 --105 per second) conditions. The loading rate or strain rate can affect the material properties such as elastic modulus, yield strength, work hardening, and ductility. To ensure product quality and reliability under impact conditions, the mechanical responses of materials under dynamic loading conditions must be characterized. A Kolsky bar is a tool that can be used to study the uniaxial compressive constitutive behavior of materials under high strain rates. The goal of this thesis is to develop a miniature Tensile Kolsky bar that can be used to test materials with thickness on the order of 200 micrometers (thin foils). The system consists of a cylindrical launch tube with an internal striker, a rectangular incident bar and a transmitted bar. The specimen is held in pockets that were milled directly into the incident and transmitted bar. The rectangular incident and transmitted bars facilitate specimen and strain gage mounting. The rectangular section also provides a reduced cross sectional bar area compared to a bar of circular cross section with diameter equivalent to the width of the rectangular bar, which increases the system sensitivity. This thesis presents the detailed description of the miniature Kolsky bar device, specimen geometry, diagnostic techniques and different calibration and validation techniques used for developing the system. The Kolsky bar setup was used to test 99.9 percent pure magnesium at two different strain rates (5000 and 10000 per second). Specimens were cut from billets processed via the 4Bc equal channel angular extrusion route and were tested in three different directions: extrusion, longitudinal and transverse. The results from the

  13. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    SciTech Connect

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-12-01

    The U.S. Department of Energy selected the high temperature gas-cooled reactor as the basis for the Next Generation Nuclear Plant (NGNP). The NGNP will demonstrate the use of nuclear power for electricity, hydrogen production, and process heat applications. The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. An intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding. This report describes the preliminary results of a scoping study that evaluated the diffusion welding process parameters and the resultant mechanical properties of diffusion welded joints using Alloy 800H. The long-term goal of the program is to progress towards demonstration of small heat exchanger unit cells fabricated with diffusion welds. Demonstration through mechanical testing of the unit cells will support American Society of Mechanical Engineers rules and standards development, reduce technical risk, and provide proof of concept for heat exchanger fabrication methods needed to deploy heat exchangers in several potential NGNP configurations.1 Researchers also evaluated the usefulness of modern thermodynamic and diffusion computational tools (Thermo-Calc and Dictra) in optimizing the parameters for diffusion welding of Alloy 800H. The modeling efforts suggested a temperature of 1150 C for 1 hour with an applied pressure of 5 MPa using 15 {micro}m nickel foil as joint filler to reduce chromium oxidation on the welded surfaces. Good agreement between modeled and experimentally determined concentration gradients was achieved

  14. Mechanical characterization of sub-100-nm-thick Au thin films by electrostatically actuated tensile testing with several strain rates

    NASA Astrophysics Data System (ADS)

    Oh, Hyun-Jin; Kawase, Shinya; Hanasaki, Itsuo; Isono, Yoshitada

    2014-02-01

    We have developed the tensile testing device based on MEMS technology and applied it to the Au thin films with thickness in the sub-100-nm regime. The specimen was fabricated by thermal deposition and sputtering processes in the course of device fabrication. This technique of device fabrication in combination with the specimen realizes the precise loading direction without preloading before tensile tests. The loads were applied electrostatically by the comb-drive actuator. The obtained Young’s modulus was 28 ± 3 GPa and was insensitive to the strain rate. The 0.2% yield strength was in the range from 192 to 519 MPa with a trend of decrease with decreasing strain rate in the range from 5 × 10-5 to 5 × 10-2 s-1.

  15. Liquid Metal Embrittlement in Resistance Spot Welding and Hot Tensile Tests of Surface-refined TWIP Steels

    NASA Astrophysics Data System (ADS)

    Barthelmie, J.; Schram, A.; Wesling, V.

    2016-03-01

    Automotive industry strives to reduce vehicle weight and therefore fuel consumption and carbon dioxide emissions. Especially in the auto body, material light weight construction is practiced, but the occupant safety must be ensured. These requirements demand high-strength steels with good forming and crash characteristics. Such an approach is the use of high- manganese-content TWIP steels, which achieve strengths of around 1,000 MPa and fracture strains of more than 60%. Welding surface-refined TWIP steels reduces their elongation at break and produces cracks due to the contact with liquid metal and the subsequent liquid metal embrittlement (LME). The results of resistance spot welds of mixed joints of high-manganese- content steel in combination with micro-alloyed ferritic steel and hot tensile tests are presented. The influence of different welding parameters on the sensitivity to liquid metal embrittlement is investigated by means of spot welding. In a high temperature tensile testing machine, the influence of different parameters is determined regardless of the welding process. Defined strains just below or above the yield point, and at 25% of elongation at break, show the correlation between the applied strain and liquid metal crack initiation. Due to the possibility to carry out tensile tests on a wide range of temperatures, dependencies of different temperatures of the zinc coating to the steel can be identified. Furthermore, the attack time of the zinc on the base material is investigated by defined heating periods.

  16. Acoustic emission monitoring of tensile testing of corroded and un-corroded clad aluminum 2024-T3 and characterization of effects of corrosion on AE source events and material tensile properties

    NASA Astrophysics Data System (ADS)

    Okafor, A. Chukwujekwu; Natarajan, Shridhar

    2014-02-01

    Corrosion damage affects structural integrity and deteriorates material properties of aluminum alloys in aircraft structures. Acoustic Emission (AE) is an effective nondestructive evaluation (NDE) technique for monitoring such damages and predicting failure in large structures of an aircraft. For successful interpretation of data from AE monitoring, sources of AE and factors affecting it need to be identified. This paper presents results of AE monitoring of tensile testing of corroded and un-corroded clad Aluminum 2024-T3 test specimens, and characterization of the effects of strain-rate and corrosion damage on material tensile properties and AE source events. Effect of corrosion was studied by inducing corrosion in the test specimens by accelerated corrosion testing in a Q-Fog accelerated corrosion chamber for 12 weeks. Eight (8) masked dog-bone shaped specimens were placed in the accelerated corrosion chamber at the beginning of the test. Two (2) dog-bone shaped specimens were removed from the corrosion chamber after exposure time of 3, 6, 9, and 12 weeks respectively, and subjected to tension testing till specimen failure along with AE monitoring, as well as two (2) reference samples not exposed to corrosion. Material tensile properties (yield strength, ultimate tensile strength, toughness, and elongation) obtained from tension test and AE parameters obtained from AE monitoring were analyzed and characterized. AE parameters increase with increase in exposure period of the specimens in the corrosive environment. Aluminum 2024-T3 is an acoustically silent material during tensile deformation without any damage. Acoustic emission events increase with increase of corrosion damage and with increase in strain rate above a certain value. Thus AE is suitable for structural health monitoring of corrosion damage. Ultimate tensile strength, toughness and elongation values decrease with increase of exposure period in corrosion chamber.

  17. Self-aligning hydraulic piston assembly for tensile testing of ceramic

    DOEpatents

    Liu, K.C.

    1987-08-18

    The present invention is directed to a self-aligning grip housing assembly that can transmit an uniaxial load to a tensile specimen without introducing bending stresses into the specimen. Disposed inside said grip housing assembly are a multiplicity of supporting pistons connected to a common source of pressurized oil that carry equal shares of the load applied to the specimen regardless whether there is initial misalignment between the specimen load column assembly and housing axis. 4 figs.

  18. Self-aligning hydraulic piston assembly for tensile testing of ceramic

    DOEpatents

    Liu, Kenneth C.

    1987-01-01

    The present invention is directed to a self-aligning grip housing assembly that can transmit an uniaxial load to a tensil specimen without introducing bending stresses into the specimen. Disposed inside said grip housing assembly are a multiplicity of supporting pistons connected to a common source of pressurized oil that carry equal shares of the load applied to the specimen irregardless whether there is initial misalignment between the specimen load column assembly and housing axis.

  19. Analysis of the Deformation and Damage Mechanisms of Pearlitic Steel by EBSD and "in-situ" SEM Tensile Tests

    NASA Astrophysics Data System (ADS)

    Sidhom, Habib; Yahyaoui, H.; Braham, C.; Gonzalez, G.

    2015-07-01

    The processes governing the deformation and damage of C70 pearlitic steel were investigated in nanometer and micrometer scales using electron backscatter diffraction technique and "in-situ" scanning electron microscope tensile testing. The ferrite behavior was identified by "in-situ" x-ray tensile tests. Investigations were carried out on annealed microstructure with two interlamellar spacings of Sp = 170 and Sp = 230 nm. It is shown that pearlite yielding is controlled by the deformation mechanisms occurring in ferrite. Deformation and damage mechanisms were proposed. At low strain, pearlite deforms homogeneously with low misorientation (<5°) inside the pearlite colonies and elongates the cementite plates. At high strain, pearlite deforms heterogeneously in intense localized shear bands inside the more favorably oriented pearlite colonies. Misorientation reaches values up to 15°. Cementite deforms by an offset of lamella along the shear bands. The nucleation of these shear bands occurs at strain level of E 11 = 7% for coarse pearlite and at a higher value for fine pearlite. Damage occurs by brittle fracture of the elongated cementite lamellae parallel to the tensile axis and which are developed by shear micro-cracks along the slip bands. The plastic-induced damage is thus delayed by the fine pearlite structure.

  20. High-speed imaging on static tensile test for unidirectional CFRP

    NASA Astrophysics Data System (ADS)

    Kusano, Hideaki; Aoki, Yuichiro; Hirano, Yoshiyasu; Kondo, Yasushi; Nagao, Yosuke

    2008-11-01

    The objective of this study is to clarify the fracture mechanism of unidirectional CFRP (Carbon Fiber Reinforced Plastics) under static tensile loading. The advantages of CFRP are higher specific stiffness and strength than the metal material. The use of CFRP is increasing in not only the aerospace and rapid transit railway industries but also the sports, leisure and automotive industries. The tensile fracture mechanism of unidirectional CFRP has not been experimentally made clear because the fracture speed of unidirectional CFRP is quite high. We selected the intermediate modulus and high strength unidirectional CFRP laminate which is a typical material used in the aerospace field. The fracture process under static tensile loading was captured by a conventional high-speed camera and a new type High-Speed Video Camera HPV-1. It was found that the duration of fracture is 200 microseconds or less, then images taken by a conventional camera doesn't have enough temporal-resolution. On the other hand, results obtained by HPV-1 have higher quality where the fracture process can be clearly observed.

  1. NGNP Project 2011 Status and Path Forward

    SciTech Connect

    L.E. Demick

    2011-12-01

    High Temperature Gas Reactor (HTGR) technology can play an important role in the United States’ energy future by extending the use of nuclear energy for non-electricity energy production missions as well as continuing to provide a considerable base load electric power generation capability. Extending nuclear energy into the industrial and transportation sectors through the co-production of process heat and electricity provides safe and reliable energy for these sectors in an environmentally responsible manner. The safety case for the modular HTGR provides a substantial improvement in nuclear plant safety for the protection of the public and the environment, and supports collocation of the HTGR with major industrial facilities. The NGNP Project at the Idaho National Laboratory has been working toward an objective of commercializing the HTGR technology under DOE direction since 2006. The Project is undergoing a quantum shift in direction and scope as a result of recent DOE decisions. This paper summarizes where the Project has been, where it is at the time of this writing and what is needed in future activities to commercialize HTGR technology.

  2. Summary of Bounding Requirements for the NGNP Demonstration Plant F&ORs

    SciTech Connect

    Not Listed

    2008-06-01

    This report documents bounding functional and operating requirements (F&ORs)for the Next Generation Nuclear Plant (NGNP) Project to support selection of the nuclear system design and specification of the operating conditions and configuration of NGNP once the nuclear system design is selected. These requirements supplement the detailed F&ORs for NGNP developed in the FY07 NGNP Pre-conceptual design work.

  3. NGNP Risk Management Database: A Model for Managing Risk

    SciTech Connect

    John Collins

    2009-09-01

    To facilitate the implementation of the Risk Management Plan, the Next Generation Nuclear Plant (NGNP) Project has developed and employed an analytical software tool called the NGNP Risk Management System (RMS). A relational database developed in Microsoft® Access, the RMS provides conventional database utility including data maintenance, archiving, configuration control, and query ability. Additionally, the tool’s design provides a number of unique capabilities specifically designed to facilitate the development and execution of activities outlined in the Risk Management Plan. Specifically, the RMS provides the capability to establish the risk baseline, document and analyze the risk reduction plan, track the current risk reduction status, organize risks by reference configuration system, subsystem, and component (SSC) and Area, and increase the level of NGNP decision making.

  4. Dual phase versus TRIP strip steels: Microstructural changes as a consequence of quasi-static and dynamic tensile testing

    SciTech Connect

    Oliver, S.; Jones, T.B.; Fourlaris, G. . E-mail: g.fourlaris@swan.ac.uk

    2007-04-15

    The development of present day and future vehicles is being driven by the need to simultaneously reduce mass and increase passenger and pedestrian safety. For this reason, the steel industry has developed strip steel grades with suitable properties, as required for meeting the demands placed on the automotive manufacturers. Two of these strip steel grades are the Dual Phase (DP) and the Transformation Induced Plasticity (TRIP) steels, which are thought to offer solutions for critical crash component criteria. Limited published information is available on the changes in microstructure of these novel strip steel grades at different rates of deformation. This paper examines the change in microstructure of a range of both commercial and experimental DP and TRIP strip steel grades, which were tensile tested at low (0.001 s{sup -1}) and very high strain rates (200 s{sup -1}). The DP and TRIP microstructures were characterised in terms of ferrite grain size, ferrite grain elongation and volume fraction of constituent phases. The specimens were examined following deformation and compared to the as-received condition to assess microstructural changes. This paper concentrates only on microstructural changes through dynamic tensile testing of DP and TRIP grades at low and high strain rates. The full crash performance data from the dynamic tensile tests and crushing of box sections is presented in a separate publication. [S. Oliver, G. Fourlaris and T.B. Jones, 'Dual Phase versus TRIP strip steels: a comparison of dynamic properties for automotive crash performance', Materials Science and Technology, 2006 (submitted for publication)].

  5. Rapid heating tensile tests of hydrogen-charged high-energy-rate-forged 316L stainless steel

    SciTech Connect

    Mosley, W.C.

    1989-05-19

    316L stainless steel is a candidate material for construction of equipment that will be exposed to tritium. Proper design of the equipment will require an understanding of how tritium and its decay product helium affect mechanical properties. This memorandum describes results of rapid heating tensile testing of hydrogen-charged specimens of high-energy-rate-forged (HERF) 316L stainless steel. These results provide a data base for comparison with uncharged and tritium-charged-and-aged specimens to distinguish the effects of hydrogen and helium. Details of the experimental equipment and procedures and results for uncharged specimens were reported previously. 3 refs., 10 figs.

  6. In-situ SAXS study on PET/ PMMT composites during tensile tests

    NASA Astrophysics Data System (ADS)

    Wei-Dong, Cheng; Xiao-Hua, Gu; Xue, Song; Peng, Zeng; Zhao-Jun, Wu; Xue-Qing, Xing; Guang, Mo; Zhong-Hua, Wu

    2016-01-01

    The nanostructures during the tensile drawing of poly(ethylene terephthalate) (PET)/hexadecyl triphenyl phosphonium bromide montmorillonite (PMMT) nanocomposites were studied by in-situ small angle x-ray scattering. For strain higher than the yield point, the scattering intensity increases dramatically due to the nucleation and growth of nanovoids and crystals. The nanovoids and crystals are significantly dependent on the heating temperature. The effective filling of PMMT in the PET matrix provokes a strong restriction to the long period. The peaks of the long period disappear gradually with the deformation strain increasing from 0% to 34%. Project supported by the National Natural Science Foundation of China (Grant Nos. U1232203, U1432104, U1332107, 11305198, and 11405199), the Program for Young Teachers Scientific Research in Qiqihar University, China (Grant No. 2012k-Z02), and the Natural Science Foundation of Heilongjiang Province, China (Grant No. E201259).

  7. Tensile testing of Fe and FeCr nanowires using molecular dynamics simulations

    SciTech Connect

    Byggmästar, J. Granberg, F.; Kuronen, A.; Nordlund, K.; Henriksson, K. O. E.

    2015-01-07

    Using molecular dynamics, we have studied the behaviour of cylindrical [001]-oriented Fe and FeCr nanowires under uniaxial tensile strain with both an embedded atom method (EAM) and a Tersoff-like bond order potential. The mechanical properties were analysed and the deformation mechanism was studied and compared between the potentials. The effects of chromium content and size of the wire were studied. Both potentials show elongation by deformation twinning in the 〈111〉/(211) system resulting in a significantly stiffer and stronger [110]-axial nanowire. The pure iron nanowires are elastically softer than bulk iron and an addition of chromium has both a softening and weakening effect. The bond order potential shows a strong dependence on chromium concentration, while the dependence is considerably weaker for the EAM potential.

  8. Nonlinear acoustic approach to material characterisation of polymers and composites in tensile tests.

    PubMed

    Solodov, I; Pfleiderer, K; Gerhard, H; Busse, G

    2004-04-01

    The paper reports on experimental study of elastic nonlinearity of polymers and glass fibre-reinforced (GFR-) composites in a wide range of tensile stress applied (up to a fracture limit). Focused slanted transmission mode (FSTM) of air-coupled ultrasound is adapted for remote generation and detection of flexural waves in the samples of plastics. Local noncontact measurements of flexural wave velocity as a function of static strain are used to calculate the second-order nonlinearity parameters beta2 and study their behaviour through a loading cycle. Molecular untangling and crazing phenomena are identified, respectively, with maxima of positive and negative beta2 in thermoplastics. In composites, mechanics of fibre-matrix interaction is considered for brittle and plastic fractures. Hysteresis in velocity variation during loading-unloading cycle is used as an indicator of residual defect accumulation. PMID:15047422

  9. Stretch calculated from grip distance accurately approximates mid-specimen stretch in large elastic arteries in uniaxial tensile tests.

    PubMed

    Tian, Lian; Henningsen, Joseph; Salick, Max R; Crone, Wendy C; Gunderson, McLean; Dailey, Seth H; Chesler, Naomi C

    2015-07-01

    The mechanical properties of vascular tissues affect hemodynamics and can alter disease progression. The uniaxial tensile test is a simple and effective method for determining the stress-strain relationship in arterial tissue ex vivo. To enable calculation of strain, stretch can be measured directly with image tracking of markers on the tissue or indirectly from the distance between the grips used to hold the specimen. While the imaging technique is generally considered more accurate, it also requires more analysis, and the grip distance method is more widely used. The purpose of this study is to compare the stretch of the testing specimen calculated from the grip distance method to that obtained from the imaging method for canine descending aortas and large proximal pulmonary arteries. Our results showed a significant difference in stretch between the two methods; however, this difference was consistently less than 2%. Therefore, the grip distance method is an accurate approximation of the stretch in large elastic arteries in the uniaxial tensile test. PMID:25881308

  10. Stretch calculated from grip distance accurately approximates mid-specimen stretch in large elastic arteries in uniaxial tensile tests

    PubMed Central

    Tian, Lian; Henningsen, Joseph; Salick, Max R.; Crone, Wendy C.; Gunderson, McLean; Dailey, Seth H.; Chesler, Naomi C.

    2015-01-01

    The mechanical properties of vascular tissues affect hemodynamics and can alter disease progression. The uniaxial tensile test is a simple and effective method for determining the stress-strain relationship in arterial tissue ex vivo. To enable calculation of strain, stretch can be measured directly with image tracking of markers on the tissue or indirectly from the distance between the grips used to hold the specimen. While the imaging technique is generally considered more accurate, it also requires more analysis, and the grip distance method is more widely used. The purpose of this study is to compare the stretch of the testing specimen calculated from the grip distance method to that obtained from the imaging method for canine descending aortas and large proximal pulmonary arteries. Our results showed a significant difference in stretch between the two methods; however, this difference was consistently less than 2%. Therefore, the grip distance method is an accurate approximation of the stretch in large elastic arteries in the uniaxial tensile test. PMID:25881308

  11. Advantages of a 3-parameter reduced constitutive model for the measurement of polymers elastic modulus using tensile tests

    NASA Astrophysics Data System (ADS)

    Blaise, A.; André, S.; Delobelle, P.; Meshaka, Y.; Cunat, C.

    2016-04-01

    Exact measurements of the rheological parameters of time-dependent materials are crucial to improve our understanding of their intimate relation to the internal bulk microstructure. Concerning solid polymers and the apparently simple determination of Young's modulus in tensile tests, international standards rely on basic protocols that are known to lead to erroneous values. This paper describes an approach allowing a correct measurement of the instantaneous elastic modulus of polymers by a tensile test. It is based on the use of an appropriate reduced model to describe the behavior of the material up to great strains, together with well-established principles of parameter estimation in engineering science. These principles are objective tools that are used to determine which parameters of a model can be correctly identified according to the informational content of a given data set. The assessment of the methodology and of the measurements is accomplished by comparing the results with those obtained from two other physical experiments, probing the material response at small temporal and length scales, namely, ultrasound measurements with excitation at 5 MHz and modulated nanoindentation tests over a few nanometers of amplitude.

  12. Interaction of heat production, strain rate and stress power in a plastically deforming body under tensile test

    NASA Technical Reports Server (NTRS)

    Paglietti, A.

    1982-01-01

    At high strain rates the heat produced by plastic deformation can give rise to a rate dependent response even if the material has rate independent constitutive equations. This effect has to be evaluated when interpreting a material test, or else it could erroneously be ascribed to viscosity. A general thermodynamic theory of tensile testing of elastic-plastic materials is given in this paper; it is valid for large strain at finite strain rates. It enables discovery of the parameters governing the thermodynamic strain rate effect, provides a method for proper interpretation of the results of the tests of dynamic plasticity, and suggests a way of planning experiments in order to detect the real contribution of viscosity.

  13. Ultimate Tensile Strength as a Function of Test Rate for Various Ceramic Matrix Composites at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Bansal, Narottam P.; Gyekenyesi, John P.

    2002-01-01

    Ultimate tensile strength of five different continuous fiber-reinforced ceramic composites, including SiC/BSAS (2D 2 types), SiC/MAS-5 (2D), SiC/SiC (2D enhanced), and C/SiC(2D) was determined as a function of test rate at I 100 to 1200 'C in air. All five composite materials exhibited a significant dependency of ultimate strength on test rate such that the ultimate strength decreased with decreasing test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress rate) to another (constant stress loading) for SiC/BSAS suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law type of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics.

  14. Hydrogen-induced crack nucleation in tensile testing of EUROFER 97 and ODS-EUROFER steels at elevated temperature

    NASA Astrophysics Data System (ADS)

    Malitckii, Evgenii; Yagodzinskyy, Yuriy; Hänninen, Hannu

    2015-11-01

    The effect of continuous hydrogen charging on tensile properties of EUROFER 97 and ODS-EUROFER steels was studied at room and elevated temperatures of 100 °C and 300 °C. The hydrogen effect decreases with increase of the temperature for ODS-EUROFER steel, while susceptibility to hydrogen of EUROFER 97 steel remains approximately the same at all testing temperatures. Continuous hydrogen charging results in a reduction of the grain boundary cohesion of the EUROFER 97 and ODS-EUROFER steels tested at RT. With increase of the testing temperature up to 300 °C EUROFER 97 steel exhibits relatively high amount of micro-cracks which agglomerate in sub-micrometer size cracks, while the hydrogen-induced intergranular crack nucleation in ODS-EUROFER steel is effectively suppressed. Possible mechanism of the hydrogen-induced crack nucleation and propagation under applied external stress is discussed.

  15. Strain localization during tensile Hopkinson bar testing of commercially pure titanium and Ti6Al4V titanium alloy

    NASA Astrophysics Data System (ADS)

    Moćko, Wojciech; Kruszka, Leopold; Brodecki, Adam

    2015-09-01

    The goal of the analysis was to determine the strain localization for various specimen shapes (type A and type B according to PN-EN ISO 26203-1 standard) and different loading conditions, i.e. quasi- static and dynamic. Commercially pure titanium (Grade 2) and titanium alloy Ti6Al4V (Grade 5) were selected for the tests. Tensile loadings were applied out using servo-hydraulic testing machine and tensile Hopkinson bar with pre-tension. The results were recorded using ARAMIS system cameras and fast camera Phantom V1210, respectively at quasi-static and dynamic loading conditions. Further, specimens outline was determined on the basis of video data using TEMA MOTION software. The strain distribution on the specimen surface was estimated using digital image correlation method. The larger radius present in the specimen of type B in comparison to specimen of type A, results in slight increase of the elongation for commercially pure titanium at both quasi-static and dynamic loading conditions. However this effect disappears for Ti6Al4V alloy. The increase of the elongation corresponds to the stronger necking effect. Material softening due to increase of temperature induced by plastic work was observed at dynamic loading conditions. Moreover lower elongation at fracture point was found at high strain rates for both materials.

  16. The statistical analysis techniques to support the NGNP fuel performance experiments

    NASA Astrophysics Data System (ADS)

    Pham, Binh T.; Einerson, Jeffrey J.

    2013-10-01

    This paper describes the development and application of statistical analysis techniques to support the Advanced Gas Reactor (AGR) experimental program on Next Generation Nuclear Plant (NGNP) fuel performance. The experiments conducted in the Idaho National Laboratory's Advanced Test Reactor employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule. The tests are instrumented with thermocouples embedded in graphite blocks and the target quantity (fuel temperature) is regulated by the He-Ne gas mixture that fills the gap volume. Three techniques for statistical analysis, namely control charting, correlation analysis, and regression analysis, are implemented in the NGNP Data Management and Analysis System for automated processing and qualification of the AGR measured data. The neutronic and thermal code simulation results are used for comparative scrutiny. The ultimate objective of this work includes (a) a multi-faceted system for data monitoring and data accuracy testing, (b) identification of possible modes of diagnostics deterioration and changes in experimental conditions, (c) qualification of data for use in code validation, and (d) identification and use of data trends to support effective control of test conditions with respect to the test target. Analysis results and examples given in the paper show the three statistical analysis techniques providing a complementary capability to warn of thermocouple failures. It also suggests that the regression analysis models relating calculated fuel temperatures and thermocouple readings can enable online regulation of experimental parameters (i.e. gas mixture content), to effectively maintain the fuel temperature within a given range.

  17. The statistical analysis techniques to support the NGNP fuel performance experiments

    SciTech Connect

    Binh T. Pham; Jeffrey J. Einerson

    2013-10-01

    This paper describes the development and application of statistical analysis techniques to support the Advanced Gas Reactor (AGR) experimental program on Next Generation Nuclear Plant (NGNP) fuel performance. The experiments conducted in the Idaho National Laboratory’s Advanced Test Reactor employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule. The tests are instrumented with thermocouples embedded in graphite blocks and the target quantity (fuel temperature) is regulated by the He–Ne gas mixture that fills the gap volume. Three techniques for statistical analysis, namely control charting, correlation analysis, and regression analysis, are implemented in the NGNP Data Management and Analysis System for automated processing and qualification of the AGR measured data. The neutronic and thermal code simulation results are used for comparative scrutiny. The ultimate objective of this work includes (a) a multi-faceted system for data monitoring and data accuracy testing, (b) identification of possible modes of diagnostics deterioration and changes in experimental conditions, (c) qualification of data for use in code validation, and (d) identification and use of data trends to support effective control of test conditions with respect to the test target. Analysis results and examples given in the paper show the three statistical analysis techniques providing a complementary capability to warn of thermocouple failures. It also suggests that the regression analysis models relating calculated fuel temperatures and thermocouple readings can enable online regulation of experimental parameters (i.e. gas mixture content), to effectively maintain the fuel temperature within a given range.

  18. Effect of lateral contraction and magnetism on the energy release upon fracture in metals: First-principles computational tensile tests

    NASA Astrophysics Data System (ADS)

    Tian, Z. X.; Yan, J. X.; Xiao, W.; Geng, W. T.

    2009-04-01

    On many occasions, there is an energy release upon fracture of materials. Taking the Σ5 (210) grain boundary in nickel as an example, we have studied the effect of lateral contraction (the Poisson effect) upon stretching and the effect of magnetism on the energy release at the break point, using density-functional theory computational tensile tests. For both clean and sulfur segregated grain boundaries, our calculations show that the Poisson effect can reduce the total energy of the grain-boundary system remarkably. For Σ3 (111) grain boundary, however, lateral optimization of the computation cell has only a minor effect because of the close packing of the Ni (111) plane. Surprisingly, magnetism is found to reduce much of the energy release upon fracture for grain boundaries for such a weak magnetic metal. As a result, the calculated ultimate tensile strength of the material will be significantly diminished. Segregated sulfur atoms reduce the energy barrier between metastable and ground-state configurations in straining procedure. Near the break point, spin polarization of the interfacial atoms is significantly enhanced which introduces an extra energy lowering of the system.

  19. Comparison of Superelasticity of Nickel Titanium Orthodontic Arch wires using Mechanical Tensile Testing and Correlating with Electrical Resistivity

    PubMed Central

    Sivaraj, Aravind

    2013-01-01

    Background: Application of light and continuous forces for optimum physiological response and least damage to the tooth supporting structures should be the primary aim of the orthodontist. Nickel titanium alloys with the properties of excellent spring back, super elasticity and wide range of action is one of the natural choices for the clinicians to achieve this goal. In recent periods, various wire manufacturers have come with a variety of wires exhibiting different properties. It is the duty of the clinician to select appropriate wires during various stages of treatment for excellent results. For achieving this evaluation of the properties of these wires is essential. Materials & Methods: This study is focussed on evaluating the super elastic property of eight groups of austenite active nickel titanium wires. Eight groups of archwires bought from eight different manufacturers were studied. These wires were tested through mechanical tensile testing and electrical resistivity methods. Results: Unloading curves were carefully assessed for superelastic behaviour on deactivation. Rankings of the wires tested were based primarily upon the unloading curve’s slope Conclusion: Ortho organisers wires ranked first and superior, followed by American Orthodontics and Ormco A wires. Morelli and GAClowland NiTi wires were ranked last. It can be concluded that the performance of these wires based on rankings should be further evaluated by clinical studies. How to cite this article: Sivaraj A. Comparison of Superelasticity of Nickel Titanium Orthodontic Arch wires using Mechanical Tensile Testing and Correlating with Electrical Resistivity. J Int Oral Health 2013; 5(3):1-12. PMID:24155596

  20. Reliability design and assessment of a micro-probe using the results of a tensile test of a beryllium-copper alloy thin film

    NASA Astrophysics Data System (ADS)

    Park, Jun-Hyub; Shin, Myung-Soo

    2011-09-01

    This paper describes the results of tensile tests for a beryllium-copper (BeCu) alloy thin film and the application of the results to the design of a probe. The copper alloy films were fabricated by electroplating. To obtain the tensile characteristics of the film, the dog-bone type specimen was fabricated by the etching method. The tensile tests were performed with the specimen using a test machine developed by the authors. The BeCu alloy has an elastic modulus of 119 GPa and the 0.2% offset yield and ultimate tensile strengths of 1078 MPa and 1108 MPa, respectively. The design and manufacture of a smaller probe require higher pad density and smaller pad-pitch chips. It should be effective in high-frequency testing. For the design of a new micro-probe, we investigated several design parameters that may cause problems, such as the contact force and life, using the tensile properties and the design of experiment method in conjunction with finite element analysis. The optimal dimensions of the probe were found using the response surface method. The probe with optimal dimensions was manufactured by a precision press process. It was verified that the manufactured probe satisfied the life, the contact force and the over drive through the compression tests and the life tests of the probes.

  1. Determination of carbon fiber adhesion to thermoplastic polymers using the single fiber/matrix tensile test

    NASA Technical Reports Server (NTRS)

    Bascom, W. D.; Cordner, L. W.; Hinkley, J. L.; Johnston, N. J.

    1986-01-01

    The single fiber adhesion shear test has been adapted to testing the adhesion between carbon fiber and thermoplastic polymers. Tests of three thermoplastics, polycarbonate, polyphenylene oxide and polyetherimide indicate the shear adhesion strength is significantly less than of an epoxy polymer to the same carbon fiber.

  2. Determination of the Young's modulus of the epicuticle of the smooth adhesive organs of Carausius morosus using tensile testing

    PubMed Central

    Bennemann, Michael; Backhaus, Stefan; Scholz, Ingo; Park, Daesung; Mayer, Joachim; Baumgartner, Werner

    2014-01-01

    Adhesive organs like arolia of insects allow these animals to climb on different substrates by creating high adhesion forces. According to the Dahlquist criterion, adhesive organs must be very soft, exhibiting an effective Young's modulus of below 100 kPa to adhere well to substrates. Such a low effective Young's modulus allows the adhesive organs to make almost direct contact with the substrate and results in van der Waals forces along with capillary forces. In previous studies, the effective Young's moduli of adhesive organs were determined using indentation tests, revealing their structure to be very soft. However, adhesive organs show a layered structure, thus the measured values comprise the effective Young's moduli of several layers of the adhesive organs. In this study, a new approach is illustrated to measure the Young's modulus of the outermost layer of the arolium, i.e. of the epicuticle, of the stick insect Carausius morosus. As a result of the epicuticle being supported by upright fibres, tensile tests allow the determination of the Young's modulus of the epicuticle with hardly influence from subjacent layers. In our tensile tests, arolia of stick insects adhering on a latex membrane were stretched by stretching the membrane while the elongation of the contact area between an arolium and the membrane was recorded. For analysis, mathematical models of the mechanical system were developed. When fed with the observed elongations, these models yield estimates for the Young's modulus of the epicuticle of approximately 100 MPa. Thus, in arolia, a very thin layer (~225 nm) of a rather stiff material, which is less susceptible to abrasion, makes contact with the substrates, whereas the inner fibrous structure of arolia is responsible for their softness. PMID:25214493

  3. A Discrete Element Model for Predicting Shear Strength and Degradation of Rock Joint by Using Compressive and Tensile Test Data

    NASA Astrophysics Data System (ADS)

    Kazerani, T.; Yang, Z. Y.; Zhao, J.

    2012-09-01

    A discrete element model is proposed to examine rock strength and failure. The model is implemented by UDEC, which is developed for this purpose. The material is represented as a collection of irregular-sized deformable particles interacting at their cohesive boundaries. The interface between two adjacent particles is viewed as a flexible contact whose constitutive law controls the material fracture and fragmentation properties. To reproduce rock anisotropy, an orthotropic cohesive law is developed for the contacts, which allows their shear and tensile behaviors to be different from each other. Using a combination of original closed-form expressions and statistical calibrations, a unique set of the contact microparameters are found based on the uniaxial/triaxial compression and Brazilian tension test data of a plaster. Applying the obtained microparameters, joint specimens, made of the same plaster, are simulated, where the comparison of the obtained results to laboratory data shows a reasonable agreement.

  4. NGNP Process Heat Utilization: Liquid Metal Phase Change Heat Exchanger

    SciTech Connect

    Piyush Sabharwall; Mike Patterson; Vivek Utgikar; Fred Gunnerson

    2008-09-01

    One key long-standing issue that must be overcome to fully realize the successful growth of nuclear power is to determine other benefits of nuclear energy apart from meeting the electricity demands. The Next Generation Nuclear Plant (NGNP) will most likely be producing electricity and heat for the production of hydrogen and/or oil retrieval from oil sands and oil shale to help in our national pursuit of energy independence. For nuclear process heat to be utilized, intermediate heat exchange is required to transfer heat from the NGNP to the hydrogen plant or oil recovery field in the most efficient way possible. Development of nuclear reactor - process heat technology has intensified the interest in liquid metals as heat transfer media because of their ideal transport properties. Liquid metal heat exchangers are not new in practical applications. An important rational for considering liquid metals is the potential convective heat transfer is among the highest known. Thus explains the interest in liquid metals as coolant for intermediate heat exchange from NGNP. For process heat it is desired that, intermediate heat exchangers (IHX) transfer heat from the NGNP in the most efficient way possible. The production of electric power at higher efficiency via the Brayton Cycle, and hydrogen production, requires both heat at higher temperatures and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. Compact heat exchangers maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. High temperature IHX design requirements are governed in part by the allowable temperature drop between the outlet and inlet of the NGNP. In order to improve the characteristics of heat transfer, liquid metal phase change heat exchangers may be more effective and efficient. This paper explores the overall heat transfer characteristics and pressure drop of the phase change

  5. Comparisons of planar and tubular biaxial tensile testing protocols of the same porcine coronary arteries

    PubMed Central

    Keyes, Joseph T; Lockwood, Danielle R; Utzinger, Urs; Montilla, Leonardo G; Witte, Russell S; Vande Geest, Jonathan P

    2013-01-01

    To identify the orthotropic biomechanical behavior of arteries, researchers typically perform stretch-pressure-inflation tests on tube-form arteries or planar biaxial testing of splayed sections. We examined variations in finite element simulations (FESs) driven from planar or tubular testing of the same coronary arteries to determine what differences exist when picking one testing technique versus another. Arteries were tested in tube-form first, then tested in planar-form, and fit to a Fung-type strain energy density function. Afterwards, arteries were modeled via finite element analysis looking at stress and displacement behavior in different scenarios (e.g., tube FESs with tube- or planar-driven constitutive models). When performing FESs of tube inflation from a planar-driven constitutive model, pressure-diameter results had an error of 12.3% compared to pressure-inflation data. Circumferential stresses were different between tube- and planar-driven pressure-inflation models by 50.4% with the planar-driven model having higher stresses. This reduced to 3.9% when rolling the sample to a tube first with planar-driven properties, then inflating with tubular-driven properties. Microstructure showed primarily axial orientation in the tubular and opening-angle configurations. There was a shift towards the circumferential direction upon flattening of 8.0 . There was also noticeable collagen uncrimping in the flattened tissue. PMID:23132151

  6. Comparisons of planar and tubular biaxial tensile testing protocols of the same porcine coronary arteries.

    PubMed

    Keyes, Joseph T; Lockwood, Danielle R; Utzinger, Urs; Montilla, Leonardo G; Witte, Russell S; Vande Geest, Jonathan P

    2013-07-01

    To identify the orthotropic biomechanical behavior of arteries, researchers typically perform stretch-pressure-inflation tests on tube-form arteries or planar biaxial testing of splayed sections. We examined variations in finite element simulations (FESs) driven from planar or tubular testing of the same coronary arteries to determine what differences exist when picking one testing technique vs. another. Arteries were tested in tube-form first, then tested in planar-form, and fit to a Fung-type strain energy density function. Afterwards, arteries were modeled via finite element analysis looking at stress and displacement behavior in different scenarios (e.g., tube FESs with tube- or planar-driven constitutive models). When performing FESs of tube inflation from a planar-driven constitutive model, pressure-diameter results had an error of 12.3% compared to pressure-inflation data. Circumferential stresses were different between tube- and planar-driven pressure-inflation models by 50.4% with the planar-driven model having higher stresses. This reduced to 3.9% when rolling the sample to a tube first with planar-driven properties, then inflating with tubular-driven properties. Microstructure showed primarily axial orientation in the tubular and opening-angle configurations. There was a shift towards the circumferential direction upon flattening of 8.0°. There was also noticeable collagen uncrimping in the flattened tissue. PMID:23132151

  7. Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

    NASA Astrophysics Data System (ADS)

    Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

    2016-06-01

    The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

  8. Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

    NASA Astrophysics Data System (ADS)

    Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

    2016-04-01

    The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

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

    SciTech Connect

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

    1998-12-01

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

  10. Summary of Differences in Approach to Executing the NGNP Project

    SciTech Connect

    P.C. Hildebrandt

    2010-08-01

    The following discuss the summary differences between the NGNP Industry Alliance’s approach to execution of the NGNP Project as described in its Project Execution Strategy, and that included in the DOE’s Report to Congress on the Next Generation Nuclear Plant dated April 2010. These summary differences are not a comprehensive description of the results of a detailed gap analysis, but rather are those differences that warrant discussion in meetings between DOE executives and the private sector represented by the Alliance. In practical fact, the full range and content of the differences will not be understood until such time as detailed discussions are engaged between the DOE and the Alliance to develop a mutually agreed-to project execution plan.

  11. NGNP Risk Management Database: A Model for Managing Risk

    SciTech Connect

    John Collins; John M. Beck

    2011-11-01

    The Next Generation Nuclear Plant (NGNP) Risk Management System (RMS) is a database used to maintain the project risk register. The RMS also maps risk reduction activities to specific identified risks. Further functionality of the RMS includes mapping reactor suppliers Design Data Needs (DDNs) to risk reduction tasks and mapping Phenomena Identification Ranking Table (PIRTs) to associated risks. This document outlines the basic instructions on how to use the RMS. This document constitutes Revision 1 of the NGNP Risk Management Database: A Model for Managing Risk. It incorporates the latest enhancements to the RMS. The enhancements include six new custom views of risk data - Impact/Consequence, Tasks by Project Phase, Tasks by Status, Tasks by Project Phase/Status, Tasks by Impact/WBS, and Tasks by Phase/Impact/WBS.

  12. A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite

    NASA Technical Reports Server (NTRS)

    Hiel, Clement C.; Sumich, Mark; Chappell, David P.

    1990-01-01

    A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semi-circular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semi-circular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is under way to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout).

  13. A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite

    NASA Technical Reports Server (NTRS)

    Hiel, Clement C.; Sumich, Mark; Chappell, David P.

    1991-01-01

    A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semicircular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semicircular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is underway to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout).

  14. A curved beam test specimen for determining the interlaminar tensile strength of a laminated composite

    SciTech Connect

    Hiel, C.C.; Sumich, M.; Chappell, D.P. )

    1991-07-01

    A curved beam type of test specimen is evaluated for use in determining the through-the-thickness strength of laminated composites. Two variations of a curved beam specimen configuration (semicircular and elliptical) were tested to failure using static and fatigue loads. The static failure load for the semicircular specimens was found to be highly sensitive to flaw content, with the specimens falling into two distinct groups. This result supports the use of proof testing for structural validation. Static design allowables are derived based on the Weibull distribution. Fatigue data indicates no measured increase in specimen compliance prior to final fracture. All static and fatigue failures at room temperature dry conditions occurred catastrophically. The elliptical specimens demonstrated unusually high failure strengths indicating the presence of phenomena requiring further study. Results are also included for specimens exposed to a wet environment showing a matrix strength degradation due to moisture content. Further testing is underway to evaluate a fatigue methodology for matrix dominated failures based on residual static strength (wearout). 10 refs.

  15. Effect of Heat Treatment and Layer Orientation on the Tensile Strength of a Crystalline Rock Under Brazilian Test Condition

    NASA Astrophysics Data System (ADS)

    Guha Roy, Debanjan; Singh, T. N.

    2016-05-01

    The effect of heat treatment and the layer orientation on the tensile properties of granitic gneiss were studied under the unconfined stress condition. The tensile strength of the samples was studied using a Brazilian configuration, and the geochemical and microstructural properties were studied using the X-ray diffraction technique as well as scanning electron microscopy (SEM), respectively. The fracture pattern and the geometrical analyses were performed using the digital photographs. The results show that both the heat treatment and layer orientation have strong control on the tensile strength, force-parallel and layer-parallel strains, and on the tensile fracture geometry. A general decrease in the tensile strength of the rock was documented with the increasing heat treatment. Although, in the heat-treated samples, X-ray diffraction study do not reveal any major change in the mineral composition, but the SEM shows the development of several micro-cracks in the grains. In the samples with different layer orientation, along with the changes in the tensile strength and layer-parallel to force-parallel strain ratio, the layer activation under shear stress is also noticed. Here, the ratio between the tensile to shear stress, acting along the layers is thought to be the major controlling factor of the tensile properties of rocks, which has many applications in mining, civil constructions, and waste disposal work.

  16. Statistical properties of microcracking in polyurethane foams under tensile and creep tests: influence of temperature and density.

    NASA Astrophysics Data System (ADS)

    Deschanel, Stephanie; Vigier, Gerard; Godin, Nathalie; Vanel, Loic; Ciliberto, Sergio

    2007-03-01

    For some heterogeneous materials fracture can be described as a clustering of microcracks: global rupture being not controlled by a single event. We focus on polyurethane foams whose heterogeneities (pores) constitute the termination points where microcracks can stop. We record both the spatial and time distributions of acoustic emission emitted by a sample during mechanical tests: each microcrack nucleation corresponds to a burst of energy that can be localized on the widest face of the specimen. The probability distributions of the energy released is power-law distributed, independently of the material density, the loading mode or the mechanical behavior. On the other hand, the agreement of a power law for the time intervals between two damaging events seems to require a quasi constant stress during damaging. Moreover, we notice a behavior difference of the cumulative number of events and the cumulative energy of the localized events with temperature in the case of tensile tests and not any more for creep tests. The occurrence of a unique behavior and a power law in a restricted time interval for the cumulative number of events and the cumulative energy in creep allow us to apprehend interesting later studies of materials' lifetime prediction.

  17. An open-end burst test method to obtain uniaxial hoop tensile properties of fuel cladding in a hot cell

    NASA Astrophysics Data System (ADS)

    Nakatsuka, Masafumi; Aita, Makoto; Sakamoto, Kan; Higuchi, Toru

    2013-03-01

    The hoop stress-hoop strain relationship of fuel cladding is one of the essential input parameters for safety analysis of fuel rods. The three objectives of this paper were: to propose a burst test method for open-end tube specimens with the uniaxial hoop stress condition; to develop the necessary in-cell high temperature open-end burst (OEB) techniques to implement the method; and to determine the optimum specimen length for the proposed OEB test method. Silicone oil was selected as the pressurization medium, and it was sealed inside the specimens not by welding but by O-rings so that no axial tensile stress was induced in the specimens. The specimens with combined end plugs and O-rings were successfully assembled by manipulators in a hot cell, and a high temperature (⩽350 °C), high pressure (⩽100 MPa) seal was achieved. The optimum specimen length was determined by using ductile and embrittled tubes with various lengths of 30-60 mm and was found to be around 45 mm for typical BWR fuel rods. During the OEB test, internal pressure and diametral expansion were monitored to obtain the basic mechanical performance properties of the fuel cladding such as yield stress, ultimate strength, as well as the true hoop stress-hoop strain curve.

  18. Effects of shock-induced tensile failure on mb-Ms discrimination: Contrasts between historic nuclear explosions and the North Korean test of 9 October 2006

    NASA Astrophysics Data System (ADS)

    Patton, Howard J.; Taylor, Steven R.

    2008-07-01

    Rayleigh wave excitation is studied for an explosion source model consisting of a superposition of isotropic (monopole), tensile failure, and tectonic release point sources. The body-force representation for shock-induced, deep-seated tensile failure is a compensated linear vector dipole CLVD, where the relative strength of the CLVD is given by an index K. Rayleigh wave amplitudes are reduced owing to destructive interference between an explosive monopole and a CLVD source with vertical axis of symmetry in extension (K > 1). The effect of tensile failure on M s is to enhance the explosion-like characteristics on a plot of m b -M s . This model suggests that the success of the m b -M s discriminant results from the fact that nuclear tests were conducted under containment practices for which tensile failure is ubiquitous, while the North Korean nuclear test of 9 October 2006 is a harbinger of poor m b -M s performance when tensile failure is completely suppressed.

  19. Scaling studies and conceptual experiment designs for NGNP CFD assessment

    SciTech Connect

    D. M. McEligot; G. E. McCreery

    2004-11-01

    The objective of this report is to document scaling studies and conceptual designs for flow and heat transfer experiments intended to assess CFD codes and their turbulence models proposed for application to prismatic NGNP concepts. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/systems code calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum ("hot streaking" issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels ("hot channel" issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses have been applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant turbulent forced convection with slight transverse property variation. In a pressurized cooldown (LOFA) simulation, the flow quickly becomes laminar with some possible buoyancy influences. The flow in the lower plenum can locally be considered to be a situation of multiple hot jets into a confined crossflow -- with obstructions. Flow is expected to be turbulent with momentumdominated turbulent jets entering; buoyancy influences are estimated to be negligible in normal full power operation. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments available are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other. Two types of heat transfer experiments are being considered. One addresses the "hot channel" problem, if necessary

  20. Determination of the elastic properties of rabbit vocal fold tissue using uniaxial tensile testing and a tailored finite element model.

    PubMed

    Latifi, Neda; Miri, Amir K; Mongeau, Luc

    2014-11-01

    The aim of the present study was to quantify the effects of the specimen shape on the accuracy of mechanical properties determined from a shape-specific model generation strategy. Digital images of five rabbit vocal folds (VFs) in their initial undeformed conditions were used to build corresponding specific solid models. The displacement field of the VFs under uniaxial tensile test was then measured over the visible portion of the surface using digital image correlation. A three-dimensional finite element model was built, using ABAQUS, for each solid model, while imposing measured boundary conditions. An inverse-problem method was used, assuming a homogeneous isotropic linear elastic constitutive model. Unknown elastic properties were identified iteratively through an error minimization technique between simulated and measured force-time data. The longitudinal elastic moduli of the five rabbit VFs were calculated and compared to values from a simple analytical method and those obtained by approximating the cross-section as elliptical. The use of shape-specific models significantly reduced the standard deviation of the Young׳s moduli of the tested specimens. However, a non-parametric statistical analysis test, i.e., the Friedman test, yielded no statistically significant differences between the shape-specific method and the elliptic cylindrical finite element model. Considering the required procedures to reconstruct the shape-specific finite element model for each tissue specimen, it might be expedient to use the simpler method when large numbers of tissue specimens are to be compared regarding their Young׳s moduli. PMID:25173237

  1. The Statistical Analysis Techniques to Support the NGNP Fuel Performance Experiments

    SciTech Connect

    Bihn T. Pham; Jeffrey J. Einerson

    2010-06-01

    This paper describes the development and application of statistical analysis techniques to support the AGR experimental program on NGNP fuel performance. The experiments conducted in the Idaho National Laboratory’s Advanced Test Reactor employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule. The tests are instrumented with thermocouples embedded in graphite blocks and the target quantity (fuel/graphite temperature) is regulated by the He-Ne gas mixture that fills the gap volume. Three techniques for statistical analysis, namely control charting, correlation analysis, and regression analysis, are implemented in the SAS-based NGNP Data Management and Analysis System (NDMAS) for automated processing and qualification of the AGR measured data. The NDMAS also stores daily neutronic (power) and thermal (heat transfer) code simulation results along with the measurement data, allowing for their combined use and comparative scrutiny. The ultimate objective of this work includes (a) a multi-faceted system for data monitoring and data accuracy testing, (b) identification of possible modes of diagnostics deterioration and changes in experimental conditions, (c) qualification of data for use in code validation, and (d) identification and use of data trends to support effective control of test conditions with respect to the test target. Analysis results and examples given in the paper show the three statistical analysis techniques providing a complementary capability to warn of thermocouple failures. It also suggests that the regression analysis models relating calculated fuel temperatures and thermocouple readings can enable online regulation of experimental parameters (i.e. gas mixture content), to effectively maintain the target quantity (fuel temperature) within a given range.

  2. Effect of test temperature and strain rate on the tensile properties of high-strength, high-conductivity copper alloys

    SciTech Connect

    Zinkle, S.J.; Eatherly, W.S.

    1997-04-01

    The unirradiated tensile properties of wrought GlidCop AL25 (ITER grade zero, IGO) solutionized and aged CuCrZr, and cold-worked and aged and solutionized and aged Hycon 3HP{trademark} CuNiBe have been measured over the temperature range of 20-500{degrees}C at strain rates between 4 x 10{sup {minus}4} s{sup {minus}1} and 0.06 s{sup {minus}1}. The measured room temperature electrical conductivity ranged from 64 to 90% IACS for the different alloys. All of the alloys were relatively insensitive to strain rate at room temperature, but the strain rate sensitivity of GlidCop Al25 increased significantly with increasing temperature. The CuNiBe alloys exhibited the best combination of high strength and high conductivity at room temperature. The strength of CuNiBe decreased slowly with increasing temperature. However, the ductility of CuNiBe decreased rapidly with increasing temperature due to localized deformation near grain boundaries, making these alloy heats unsuitable for typical structural applications above 300{degrees}C. The strength and uniform elongation of GlidCop Al25 decreased significantly with increasing temperature at a strain rate of 1 x 10{sup {minus}3} s{sup {minus}1}, whereas the total elongation was independent of test temperature. The strength and ductility of CuCrZr decreased slowly with increasing temperature.

  3. The effect of spherical inclusions in metallic glass nanowires under tensile test and its relation to atomic structure

    NASA Astrophysics Data System (ADS)

    Sepulveda, Matias; Gutierrez, Gonzalo; Amigo, Nicolas

    The plastic behavior of crystalline metals is well understood. It is know that this regime is mainly mediated by nucleation and propagation of dislocations as well as by grain boundary sliding. In metallic glasses (MGs) the plastic behavior is quite different from their crystalline counterparts and a relationship between atomic-micro structure and properties remains one of the barriers that has hampered the progress to wide applications of MGs. In particular it would be desirable to have studies which directly relate the evolution of the shear bands (SBs) and glass matrix structure to each step of the applied strain, which would allow us to easily connect the evolution of the atomic structure to the stress-strain curve. Here we present a computational tensile test which shows the evolution of the atomic structure according to the strain is applied for a Cu50Zr50 metallic glass nanowire at 300 K with a Cu-Zr b2 inclusion in the center of the system with three different radius from 20 to 60 Å. The system consists of a million atoms and the local structure is analyzed by means of the Voronoi polyhedral technique and the nucleation and propagation of SBs by monitoring the local atomic shear strain. CONICyT PhD Fellowship No. 21140904.

  4. Use of Slow Strain Rate Tensile Testing to Assess the Ability of Several Superalloys to Resist Environmentally-Assisted Intergranular Cracking

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Telesman, Jack; Banik, Anthony; McDevitt, Erin

    2014-01-01

    Intergranular fatigue crack initiation and growth due to environmental degradation, especially at notched features, can often limit the fatigue life of disk superalloys at high temperatures. For clear comparisons, the effects of alloy composition on cracking in air needs to be understood and compared separately from variables associated with notches and cracks such as effective stress concentration, plastic flow, stress relaxation, and stress redistribution. The objective of this study was to attempt using simple tensile tests of specimens with uniform gage sections to compare the effects of varied alloy composition on environment-assisted cracking of several powder metal and cast and wrought superalloys including ME3, LSHR, Udimet 720(TradeMark) ATI 718Plus(Registered TradeMark) alloy, Haynes 282(Trademark), and Inconel 740(TradeMark) Slow and fast strain-rate tensile tests were found to be a useful tool to compare propensities for intergranular surface crack initiation and growth. The effects of composition and heat treatment on tensile fracture strain and associated failure modes were compared. Environment interactions were determined to often limit ductility, by promoting intergranular surface cracking. The response of various superalloys and heat treatments to slow strain rate tensile testing varied substantially, showing that composition and microstructure can significantly influence environmental resistance to cracking.

  5. Ex-situ tensile fatigue-creep testing: A powerful tool to simulate in-situ mechanical degradation in fuel cells

    NASA Astrophysics Data System (ADS)

    Sadeghi Alavijeh, A.; Venkatesan, S. V.; Khorasany, R. M. H.; Kim, W. H. J.; Kjeang, E.

    2016-04-01

    An ex-situ tensile fatigue and creep based accelerated stress test (TFC-AST) is proposed to evaluate the mechanical stability of catalyst coated membranes (CCMs) used in fuel cells. The fatigue-creep action of the TFC test is analyzed by tensile and hygrothermal expansion measurements on partially degraded specimens supplemented by microstructural characterization using transmission electron microscopy, revealing significant decay in mechanical properties as well as morphological rearrangement due to the combined fatigue and creep loading. Through comparison with in-situ hygrothermally degraded CCMs, the TFC-AST protocol is demonstrated to be an economical alternative to the costly in-situ mechanical accelerated stress tests that can reduce the test duration by more than 99%.

  6. NGNP Data Management and Analysis System Analysis and Web Delivery Capabilities

    SciTech Connect

    Cynthia D. Gentillon

    2010-09-01

    Projects for the Very High Temperature Reactor Technology Development Office provide data in support of Nuclear Regulatory Commission licensing of the very high temperature reactor. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high-temperature and high-fluence environments. In addition, thermal-hydraulic experiments are conducted to validate codes used to assess reactor safety. The Very High Temperature Reactor Technology Development Office has established the NGNP Data Management and Analysis System (NDMAS) at the Idaho National Laboratory to ensure that very high temperature reactor data are (1) qualified for use, (2) stored in a readily accessible electronic form, and (3) analyzed to extract useful results. This document focuses on the third NDMAS objective. It describes capabilities for displaying the data in meaningful ways and for data analysis to identify useful relationships among the measured quantities.

  7. TRITIUM BARRIER MATERIALS AND SEPARATION SYSTEMS FOR THE NGNP

    SciTech Connect

    Sherman, S; Thad Adams, T

    2008-07-17

    Contamination of downstream hydrogen production plants or other users of high-temperature heat is a concern of the Next Generation Nuclear Plant (NGNP) Project. Due to the high operating temperatures of the NGNP (850-900 C outlet temperature), tritium produced in the nuclear reactor can permeate through heat exchangers to reach the hydrogen production plant, where it can become incorporated into process chemicals or the hydrogen product. The concentration limit for tritium in the hydrogen product has not been established, but it is expected that any future limit on tritium concentration will be no higher than the air and water effluent limits established by the NRC and the EPA. A literature survey of tritium permeation barriers, capture systems, and mitigation measures is presented and technologies are identified that may reduce the movement of tritium to the downstream plant. Among tritium permeation barriers, oxide layers produced in-situ may provide the most suitable barriers, though it may be possible to use aluminized surfaces also. For tritium capture systems, the use of getters is recommended, and high-temperature hydride forming materials such as Ti, Zr, and Y are suggested. Tritium may also be converted to HTO in order to capture it on molecular sieves or getter materials. Counter-flow of hydrogen may reduce the flux of tritium through heat exchangers. Recommendations for research and development work are provided.

  8. An evaluation of the +/-45 deg tensile test for the determination of the in-plane shear strength of composite materials

    NASA Technical Reports Server (NTRS)

    Kellas, S.; Morton, J.; Jackson, K. E.

    1991-01-01

    The applicability of the +/-45 deg tensile test for the determination of the in-plane shear strength of advanced composite laminates is studied. The assumptions used for the development of the shear strength formulas were examined, and factors such as the specimen geometry and stacking sequence were assessed experimentally. It was found that the strength of symmetric and balanced +/-45 deg laminates depends primarily upon the specimen thickness rather than the specimen width. These findings have important implications for the +/-45 deg tensile test which is recommended by several organizations for the determination of the in-plane shear stress/strain response and the shear strength of continuous fiber reinforced composites. Modifications to the recommended practices for specimen selection and shear strength determination are suggested.

  9. Unveil the Size-Dependent Mechanical Behaviors of Individual CNT/SiC Composite Nanofibers by In Situ Tensile Tests in SEM.

    PubMed

    Yang, Yingchao; Chen, Weibing; Hacopian, Emily; Dong, Pei; Sun, Anqi; Ci, Lijie; Lou, Jun

    2016-09-01

    In situ quantitative tensile tests of individual carbon nanotube (CNT)/SiC core-shell nanofibers are carried out in both a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The incorporation of CNTs into a SiC matrix led to improved elastic modulus and fracture strength of the CNT/SiC nanofibers as compared to SiC alone. PMID:27400777

  10. Standard Problems for CFD Validation for NGNP - Status Report

    SciTech Connect

    Richard W. Johnson; Richard R. Schultz

    2010-08-01

    The U.S. Department of Energy (DOE) is conducting research and development to support the resurgence of nuclear power in the United States for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The project is called the Next Generation Nuclear Plant (NGNP) Project, which is based on a Generation IV reactor concept called the very high temperature reactor (VHTR). The VHTR will be of the prismatic or pebble bed type; the former is considered herein. The VHTR will use helium as the coolant at temperatures ranging from 250°C to perhaps 1000°C. While computational fluid dynamics (CFD) has not previously been used for the safety analysis of nuclear reactors in the United States, it is being considered for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal operational and accident situations. The “Standard Problem” is an experimental data set that represents an important physical phenomenon or phenomena, whose selection is based on a phenomena identification and ranking table (PIRT) for the reactor in question. It will be necessary to build a database that contains a number of standard problems for use to validate CFD and systems analysis codes for the many physical problems that will need to be analyzed. The first two standard problems that have been developed for CFD validation consider flow in the lower plenum of the VHTR and bypass flow in the prismatic core. Both involve scaled models built from quartz and designed to be installed in the INL’s matched index of refraction (MIR) test facility. The MIR facility employs mineral oil as the working fluid at a constant temperature. At this temperature, the index of refraction of the mineral oil is the same as that of the quartz. This provides an advantage to the

  11. Baseline Test Specimen Machining Report

    SciTech Connect

    mark Carroll

    2009-08-01

    specimens drawn from carefully controlled sections of each billet. To this end, this report will discuss the machining of the first set of test specimens that will be evaluated in this program through tensile, compressive, and flexural testing. Validation that the test specimens have been produced to the tolerances required by the applicable ASTM standards, and to the quality control levels required by this program, will demonstrate the viability of sending graphite to selected suppliers that will provide valuable and certifiable data to future data sets that are integral to the NGNP program and beyond.

  12. High-temperature tensile tester for ceramics

    NASA Technical Reports Server (NTRS)

    Smith, M.

    1974-01-01

    Apparatus measures tensile strength of rigid, low-density ceramic materials at temperatures up to 1375 K. Tensile grips mate with tensile specimen and form top and bottom of lightweight furnace. Apparatus can only be used with rigid materials and grips must be stronger than material under test.

  13. Stress-induced martensitic transformation during tensile test of full-size TF conductor jacket tube at 4.2 K

    SciTech Connect

    Yang, H. H.; Li, S. P.; Wu, Z. X.; Huang, C. J.; Huang, R. J.; Li, L. F.

    2014-01-27

    The toroidal-field (TF) conductor jacket of International Thermonuclear Experimental Reactor (ITER) is made of modified 316LN stainless steel, which is influenced by heat treatment at approximately 650 °C for 200 h to produce Nb{sub 3}Sn superconducting materials at the final stage. Due to the high electromagnetic forces arising during magnet operation, higher mechanical properties of the jacket materials at cryogenic temperatures are required. In our work, mechanical properties of the full-size TF conductor jacket tube were investigated, which satisfied the ITER requirements. Stress-induced martensitic transformation mechanism during tensile test of the conductor jacket material at 4.2 K was characterized by means of in-situ temperature dependent XRD, vibrating sample magnetometer (VSM) and in conjunction with transmission electron microscopy (TEM). The tensile behavior related to the amount of stress-induced phase transformation at cryogenic temperature was also discussed.

  14. Summary of NGNP Engineering Analysis Progress in Fiscal Year 2010

    SciTech Connect

    Phillip M. Mills

    2010-09-01

    The Engineering Analysis work package accomplished a number of activities in FY2010 that will help to inform Licensing, R&D, and detailed design activities that will be performed during the preliminary design phase in Phase 2 of the NGNP Project. These activities were in the following areas: • Fission Product Transport • DDN Update and Consolidation • Gas Reactor Lessons Learned Review • Reactor Coolant Chemistry Control • Resilient Control Systems for High Temperature Gas-cooled Reactors • Water-ingress Analysis In total, the efforts associated with the Engineering Analysis work package accomplished four (4) Level 2 milestones and two (2) internal (Level 4) milestones. Details of the activities and milestones are included in the attached report.

  15. NGNP Project Regulatory Gap Analysis for Modular HTGRs

    SciTech Connect

    Wayne Moe

    2011-09-01

    The Next Generation Nuclear Plant (NGNP) Project Regulatory Gap Analysis (RGA) for High Temperature Gas-Cooled Reactors (HTGR) was conducted to evaluate existing regulatory requirements and guidance against the design characteristics specific to a generic modular HTGR. This final report presents results and identifies regulatory gaps concerning current Nuclear Regulatory Commission (NRC) licensing requirements that apply to the modular HTGR design concept. This report contains appendices that highlight important HTGR licensing issues that were found during the RGA study. The information contained in this report will be used to further efforts in reconciling HTGR-related gaps in the NRC licensing structure, which has to date largely focused on light water reactor technology.

  16. NGNP: High Temperature Gas-Cooled Reactor Key Definitions, Plant Capabilities, and Assumptions

    SciTech Connect

    Phillip Mills

    2012-02-01

    This document is intended to provide a Next Generation Nuclear Plant (NGNP) Project tool in which to collect and identify key definitions, plant capabilities, and inputs and assumptions to be used in ongoing efforts related to the licensing and deployment of a high temperature gas-cooled reactor (HTGR). These definitions, capabilities, and assumptions are extracted from a number of sources, including NGNP Project documents such as licensing related white papers [References 1-11] and previously issued requirement documents [References 13-15]. Also included is information agreed upon by the NGNP Regulatory Affairs group's Licensing Working Group and Configuration Council. The NGNP Project approach to licensing an HTGR plant via a combined license (COL) is defined within the referenced white papers and reference [12], and is not duplicated here.

  17. Nuclear Safeguards Infrastructure Required for the Next Generation Nuclear Plant (NGNP)

    SciTech Connect

    Dr. Mark Schanfein; Philip Casey Durst

    2012-07-01

    The Next Generation Nuclear Plant (NGNP) is a Very High Temperature Gas-Cooled Reactor (VHTR) to be constructed near Idaho Falls, Idaho The NGNP is intrinsically safer than current reactors and is planned for startup ca. 2021 Safety is more prominent in the minds of the Public and Governing Officials following the nuclear reactor meltdown accidents in Fukushima, Japan The authors propose that the NGNP should be designed with International (IAEA) Safeguards in mind to support export to Non-Nuclear-Weapons States There are two variants of the NGNP design; one using integral Prismatic-shaped fuel assemblies in a fixed core; and one using recirculating fuel balls (or Pebbles) The following presents the infrastructure required to safeguard the NGNP This infrastructure is required to safeguard the Prismatic and Pebble-fueled NGNP (and other HTGR/VHTR) The infrastructure is based on current Safeguards Requirements and Practices implemented by the International Atomic Energy Agency (IAEA) for similar reactors The authors of this presentation have worked for decades in the area of International Nuclear Safeguards and are recognized experts in this field Presentation for INMM conference in July 2012.

  18. Tensile and pack compressive tests of some sheets of aluminum alloy, 1025 carbon steel, and chromium-nickel steel

    NASA Technical Reports Server (NTRS)

    Atchison, C S; Miller, James A

    1942-01-01

    Tensile and compressive stress-strain curves, stress-deviation curves, and secant modulus-stress curves are given for longitudinal and transverse specimens of 17S-T, 24S-T, and 24S-RT aluminum-alloy sheet in thicknesses from 0.032 to 0.081 inch, 1025 carbon steel sheet in thicknesses of 0.054 and 0.120 inch, and chromium-nickel steel sheet in thicknesses form 0.020 to 0.0275 inch. Significant differences were found between the tensile and the compressive stress-strain curves, and also the corresponding corollary curves; similarly, differences were found between the curves for the longitudinal and transverse directions. These differences are of particular importance in considering the compressive strength of aircraft structures made of thin sheet. They are explored further for the case of compression by giving tangent modulus-stress curves in longitudinal and transverse compression and dimensionless curves of the ratio of tangent modulus to Young's modulus and of the ratio of reduced modulus for a rectangular section to Young's modulus, both plotted against the ratio of stress to secant yield strength.

  19. Temperature increase of Zircaloy-4 cladding tubes due to plastic heat dissipation during tensile tests at 0.1-10 s-1 strain rates

    NASA Astrophysics Data System (ADS)

    Hellouin de Menibus, Arthur; Auzoux, Quentin; Besson, Jacques; Crépin, Jérôme

    2014-11-01

    This study is focused on the impact of rapid Reactivity Initiated Accident (RIA) representative strain rates (about 1 s-1 NEA, 2010) on the behavior and fracture of unirradiated cold work stress relieved Zircaloy-4 cladding tubes. Uniaxial ring tests (HT) and plane strain ring tensile tests (PST) were performed in the 0.1-10 s-1 strain rate range, at 25 °C. The local temperature increase due to plastic dissipation was measured with a high-speed infrared camera. Limited temperature increases were measured at 0.1 s-1 strain rate. Limited but not strongly localized temperature increases were measured at 1 s-1. Large temperature increase were measured at 5 and 10 s-1 (142 °C at 5 s-1 strain rate in HT tests). The local temperature increase induced heterogeneous temperature fields, which enhanced strain localization and resulted in a reduction of the plastic elongation at fracture.

  20. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

    SciTech Connect

    Haboub, Abdel; Nasiatka, James R.; MacDowell, Alastair A.; Bale, Hrishikesh A.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.

    2014-08-15

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C.

  1. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography.

    PubMed

    Haboub, Abdel; Bale, Hrishikesh A; Nasiatka, James R; Cox, Brian N; Marshall, David B; Ritchie, Robert O; MacDowell, Alastair A

    2014-08-01

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C. PMID:25173271

  2. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

    NASA Astrophysics Data System (ADS)

    Haboub, Abdel; Bale, Hrishikesh A.; Nasiatka, James R.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.; MacDowell, Alastair A.

    2014-08-01

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C.

  3. Lattice strain and damage evolution of 9-12/%Cr ferritic/martensitic steel during in situ tensile test by x-ray diffraction and small angle scattering.

    SciTech Connect

    Pan, X.; Wu, X.; Mo, K.; Chen, X,; Almer, J. D.; Ilavsky, J.; Haeffner, D. R.; Stubbins, J. F.; X-Ray Science Division; Univ. of Illinois

    2010-01-01

    In situ X-ray diffraction and small angle scattering measurements during tensile tests were performed on 9-12% Cr ferritic/martensitic steels. The lattice strains in both particle and matrix phases, along two principal directions, were directly measured. The load transfer between particle and matrix was calculated based on matrix/particle elastic mismatch, matrix plasticity and interface decohesion. In addition, the void or damage evolution during the test was measured using small angle X-ray scattering. By combining stress and void evolution during deformation, the critical interfacial strength for void nucleation was determined, and compared with pre-existing void nucleation criteria. These comparisons show that models overestimate the measured critical strength, and require a larger particle size than measured to match the X-ray observations.

  4. Machining technique prevents undercutting in tensile specimens

    NASA Technical Reports Server (NTRS)

    Moscater, R. E.; Royster, D. M.

    1968-01-01

    Machining technique prevents undercutting at the test section in tensile specimens when machining the four corners of the reduced section. Made with a gradual taper in the test section, the width of the center of the tensile specimen is less than the width at the four corners of the reduced section.

  5. CHARACTERIZATION OF TENSILE STRENGTH OF GLOVEBOX GLOVES

    SciTech Connect

    Korinko, P.; Chapman, G.

    2012-02-29

    A task was undertaken to compare various properties of different glovebox gloves, having various compositions, for use in gloveboxes at the Savannah River Site (SRS). One aspect of this project was to determine the tensile strength (TS) of the gloves. Longitudinal tensile samples were cut from 15 different gloves and tensile tested. The stress, load, and elongation at failure were determined. All of the gloves that are approved for glovebox use and listed in the glovebox procurement specification met the tensile and elongation requirements. The Viton{reg_sign} compound gloves are not listed in the specification, but exhibited lower tensile strengths than permissible based on the Butyl rubber requirements. Piercan Polyurethane gloves were the thinnest samples and exhibited the highest tensile strength of the materials tested.

  6. Tensile properties of impact ices

    NASA Technical Reports Server (NTRS)

    Chu, M. L.; Scavuzzo, R. J.; Kellackey, C. J.

    1992-01-01

    A special test apparatus was developed to measure the tensile strength of impact ices perpendicular to the direction of growth. The apparatus consists of a split tube carefully machined to minimize the effect of the joint on impact ice strength. The tube is supported in the wind tunnel by two carefully aligned bearings. During accretion the tube is turned slowly in the icing cloud to form a uniform coating of ice on the split tube specimen. The two halves of the split tube are secured firmly by a longitudinal bolt to prevent relative motion between the two halves during ice accretion and handling. Tensile test strength results for a variety of icing conditions were obtained. Both glaze and rime ice conditions were investigated. In general, the tensile strength of impact ice was significantly less than refrigerator ice. Based on the limited data taken, the median strength of rime ice was less than glaze ice. However, the mean values were similar.

  7. Effects of test environment and grain size on the tensile properties of L1 sub 2 -ordered (Co,Fe) sub 3 V alloys

    SciTech Connect

    Nishimura, C.; Liu, C.T.

    1991-01-01

    The influence of test environment, grain size, and heat treatment on the tensile properties and fracture behavior of L1{sub 2}-ordered (Co{sub 78}Fe{sub 22}){sub 3}V and (Co{sub 85}Fe{sub 15}){sub 3}V alloys was studied at room temperature. The tensile ductility depends strongly on test environments; the elongation decreases in the sequence of oxygen, vacuum, air, and distilled water. The loss in elongation is accompanied by a change in fracture mode from transgranular to intergranular. When tested in oxygen or vacuum, (Co{sub 78}Fe{sub 22}){sub 3}V specimens exhibited predominantly transgranular fracture, while (Co{sub 85}Fe{sub 15}){sub 3}V specimens exhibited essentially intergranular fracture. Grain refinement of (Co{sub 78}Fe{sub 22}){sub 3}V resulted in a ductility improvement in air, while such a beneficial effect of a grain refinement was not observed in (Co{sub 85}Fe{sub 15}){sub 3}V. These results suggest that: (1) (Co,Fe){sub 3}V alloys exhibit a moisture-induced hydrogen embrittlement and (2) grain boundaries are more intrinsically brittle in (Co{sub 85}Fe{sub 15}){sub 3}V than in (Co{sub 78}Fe{sub 22}){sub 3}V. The presence of a brittle hexagonal phase is suggested to be the reason for the observed grain-boundary brittleness in (Co{sub 85}Fe{sub 15}){sub 3}V. 29 refs., 6 figs., 2 tabs.

  8. Bond mobility mechanism in grain boundary embrittlement: First-principles tensile tests of Fe with a P-segregated {Sigma}3 grain boundary

    SciTech Connect

    Yuasa, Motohiro; Mabuchi, Mamoru

    2010-09-01

    First-principles simulated tensile tests have been performed on Fe with a P-segregated grain boundary to investigate the nature of the bond mobility mechanism in grain boundary embrittlement. The first site for bond breaking was the Fe-P bond, despite its high charge density. This is because the Fe-P bond exhibited the covalentlike characteristics of a localized bonding and the mobility of electrons was reduced. The breaking of the Fe-P bond accelerated the breaking of the Fe-Fe bond around the Fe-P bond because the Fe-P bond breaking affected the electron density of states of the Fe-Fe bond. Thus, P segregation enhanced the grain boundary embrittlement in Fe.

  9. Preliminary report on tests of tensile specimens with a part-through surface notch for a filament wound graphite/epoxy material

    NASA Technical Reports Server (NTRS)

    Harris, C. E.; Morris, D. H.

    1985-01-01

    The behavior of tensile coupons with surface notches of various semi-elliptical shapes were evaluated for specimens obtained from a filament wound graphite/epoxy cylinder. The quasi-static test results, in some instances, are inadequate for defining complete trend curves and the interpretive analysis is considered to be preliminary. Specimens with very shallow notches were observed to be notch insensitive and the unnotched strength from these specimens was determined to be 54.97 Ksi. The failure strain of the laminate was found to be 1.328%. Specimens with deeper notches were sensitive to notch depth, notch aspect ratio, and specimen width. Using the unnotched strength of 54.97 Ksi and Poe's general toughness parameter, the fracture toughness was estimated to be 27.2 Ksi square root of In. Isotropic linear elastic fracture mechanics together with the estimated fracture toughness correctly predicted the influence of notch depth, aspect ratio, and specimen finitewidth.

  10. Rapid heating tensile tests of high-energy-rate-forged 316L stainless steel containing internal helium from radioactive decay of absorbed tritium

    SciTech Connect

    Mosley, W.C.

    1990-01-01

    316L stainless steel is a candidate material for construction of equipment that will be exposed to tritium. This austenitic stainless steel is frequently used in the high-energy-rate-forged (HERF) metallurgical condition to take advantage of increased strength produced by cold work introduced by this process. Proper design of tritium-handling equipment will require an understanding of how helium-3, the product of radioactive decay of tritium, affects mechanical properties. This report describes results of elevated-temperature tensile testing of HERF 316L stainless steel specimens containing helium concentrations of 171 (calculated) atomic parts per million (appm). Results are compared with those reported previously for specimens containing 0 and 94 (measured) appm helium.

  11. Rapid heating tensile tests of high-energy-rate-forged 316L stainless steel containing internal helium from radioactive decay of absorbed tritium

    SciTech Connect

    Mosley, W.C.

    1990-12-31

    316L stainless steel is a candidate material for construction of equipment that will be exposed to tritium. This austenitic stainless steel is frequently used in the high-energy-rate-forged (HERF) metallurgical condition to take advantage of increased strength produced by cold work introduced by this process. Proper design of tritium-handling equipment will require an understanding of how helium-3, the product of radioactive decay of tritium, affects mechanical properties. This report describes results of elevated-temperature tensile testing of HERF 316L stainless steel specimens containing helium concentrations of 171 (calculated) atomic parts per million (appm). Results are compared with those reported previously for specimens containing 0 and 94 (measured) appm helium.

  12. Effect of sample test volume and geometry on the tensile mechanical behavior of SiC/SiC continuous fiber ceramic composites. Final report

    SciTech Connect

    Sankar, J.; Kelkar, A.D.; Neogi, J.

    1998-09-01

    The development of a silicon carbide-type fiber from an organometallic precursor has led to a major resurgence of interest in fiber-reinforced ceramic matrix composites. By combining this high strength fiber with a variety of ceramic matrices it has been possible to achieve tough composites offering significant potential advantages over monolithic ceramics and carbon-carbon for high temperature applications. A continuous-fiber ceramic matrix composite (CFCC) typical of materials proposed for such industrial applications as power generation, heat recovery and chemical production as well as biomedical and environmental applications was tested in uniaxial tension using a universal test machine. Test parameters investigated included: test mode (load versus displacement), test rate (0.003 mm/s, 0.03 mm/s, 50 N/s and 500 N/s), specimen geometry (straight-sided versus reduced-gauge section) and type of specimen volume (long/thin versus short/fat). Typical properties include an average elastic modulus 130 {+-} 10 Gpa, an average proportional limit stress of 45 {+-} 20 Mpa, an average ultimate tensile strength of 180 {+-} 20 MPa and an average modulus of toughness of 8.4 {+-} 2 (x10{sup 5})J/m{sup 3}.

  13. Effect of Load Rate on Tensile Strength of Various CFCCs at Elevated Temperatures: An Approach to Life Prediction Testing

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    2001-01-01

    Strength of three continuous fiber-reinforced ceramic composites, including SiC/CAS-11, SiC/MAS-5 and SiC/SiC, was determined as a function of test rate in air at 1100 - 1200 C. All three composite materials exhibited a strong dependency of strength on test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress-rate) to another (constant stress loading) suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law tyw of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology even for the composite materials at least for the short range of lifetime.

  14. Anti-buckling fatigue test assembly. [for subjecting metal specimen to tensile and compressive loads at constant temperature

    NASA Technical Reports Server (NTRS)

    Eichenbrenner, F. F.; Imig, L. A. (Inventor)

    1974-01-01

    An antibuckling fatigue test assembly is described for holding a metal specimen which is subjected to compression and to rapid cyclical heating and cooling while permitting visual observation. In an illustrative embodiment of this invention, the anti-buckling fatigue test apparatus includes first and second guide members between which the metal specimen is disposed and held, a heating assembly comprising a suitable heating source such as a quartz lamp and a reflecting assembly directing the heat onto the specimen, and a cooling assembly for directing a suitable cooling fluid such as air onto the specimen. The guide members each have a passage to permit the heat to be directed onto the specimen. An opening is provided in the reflecting assembly to permit visual inspection of that region of the specimen adjacent to the opening onto which the heat is directed.

  15. Summary of Planned Implementation for the HTGR Lessons Learned Applicable to the NGNP

    SciTech Connect

    Ian Mckirdy

    2011-09-01

    This document presents a reconciliation of the lessons learned during a 2010 comprehensive evaluation of pertinent lessons learned from past and present high temperature gas-cooled reactors that apply to the Next Generation Nuclear Plant Project along with current and planned activities. The data used are from the latest Idaho National Laboratory research and development plans, the conceptual design report from General Atomics, and the pebble bed reactor technology readiness study from AREVA. Only those lessons related to the structures, systems, and components of the Next Generation Nuclear Plant (NGNP), as documented in the recently updated lessons learned report are addressed. These reconciliations are ordered according to plant area, followed by the affected system, subsystem, or component; lesson learned; and finally an NGNP implementation statement. This report (1) provides cross references to the original lessons learned document, (2) describes the lesson learned, (3) provides the current NGNP implementation status with design data needs associated with the lesson learned, (4) identifies the research and development being performed related to the lesson learned, and (5) summarizes with a status of how the lesson learned has been addressed by the NGNP Project.

  16. NGNP Data Management and Analysis System Analysis and Web Delivery Capabilities

    SciTech Connect

    Cynthia D. Gentillon

    2011-09-01

    Projects for the Very High Temperature Reactor (VHTR) Technology Development Office provide data in support of Nuclear Regulatory Commission licensing of the very high temperature reactor. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high-temperature and high-fluence environments. The NGNP Data Management and Analysis System (NDMAS) at the Idaho National Laboratory has been established to ensure that VHTR data are (1) qualified for use, (2) stored in a readily accessible electronic form, and (3) analyzed to extract useful results. This document focuses on the third NDMAS objective. It describes capabilities for displaying the data in meaningful ways and for data analysis to identify useful relationships among the measured quantities. The capabilities are described from the perspective of NDMAS users, starting with those who just view experimental data and analytical results on the INL NDMAS web portal. Web display and delivery capabilities are described in detail. Also the current web pages that show Advanced Gas Reactor, Advanced Graphite Capsule, and High Temperature Materials test results are itemized. Capabilities available to NDMAS developers are more extensive, and are described using a second series of examples. Much of the data analysis efforts focus on understanding how thermocouple measurements relate to simulated temperatures and other experimental parameters. Statistical control charts and correlation monitoring provide an ongoing assessment of instrument accuracy. Data analysis capabilities are virtually unlimited for those who use the NDMAS web data download capabilities and the analysis software of their choice. Overall, the NDMAS provides convenient data analysis and web delivery capabilities for studying a very large and rapidly increasing database of well-documented, pedigreed data.

  17. An in-plane tensile test for rheological and formability identification: comparison between experimental and numerical FLC

    NASA Astrophysics Data System (ADS)

    Leotoing, L.; Guines, D.; Ragneau, E.

    2011-05-01

    Both accurate constitutive laws and formability limits of materials are essential for a numerical optimization of sheet forming processes. To identify these behaviors, experimental databases are needed. In this work, experiments are performed from a biaxial device able to give for a unique in-plane specimen a good prediction of rheological parameters and formability. The proposed device is a servo-hydraulic testing machine provided with four independent dynamic actuators. By localizing necking in the central zone of the specimen, the strain path in this zone is controlled by the speed ratio between the two axes and the whole forming limit diagram can be covered. The experimental forming limit curve for the aluminium alloy AA5086 is determined thanks to a rigorous procedure for detecting the onset of necking in the specimen. Material parameters (constants of both hardening law and anisotropic yield criterion) are identified from the global measurement of force versus displacement curves by means of an inverse analysis procedure. Comparison between experimental and numerical forming limit curves are presented. For the numerical FLCs, two sets of material parameters are compared, the former is identified through the classical uniaxial test and the latter thanks to the dedicated cruciform specimen.

  18. An in-plane tensile test for rheological and formability identification: comparison between experimental and numerical FLC

    SciTech Connect

    Leotoing, L.; Guines, D.; Ragneau, E.

    2011-05-04

    Both accurate constitutive laws and formability limits of materials are essential for a numerical optimization of sheet forming processes. To identify these behaviors, experimental databases are needed. In this work, experiments are performed from a biaxial device able to give for a unique in-plane specimen a good prediction of rheological parameters and formability. The proposed device is a servo-hydraulic testing machine provided with four independent dynamic actuators. By localizing necking in the central zone of the specimen, the strain path in this zone is controlled by the speed ratio between the two axes and the whole forming limit diagram can be covered. The experimental forming limit curve for the aluminium alloy AA5086 is determined thanks to a rigorous procedure for detecting the onset of necking in the specimen. Material parameters (constants of both hardening law and anisotropic yield criterion) are identified from the global measurement of force versus displacement curves by means of an inverse analysis procedure. Comparison between experimental and numerical forming limit curves are presented. For the numerical FLCs, two sets of material parameters are compared, the former is identified through the classical uniaxial test and the latter thanks to the dedicated cruciform specimen.

  19. Engineering Design Elements of a Two-Phase Thermosyphon to Trannsfer NGNP Nuclear Thermal Energy to a Hydrogen Plant

    SciTech Connect

    Piyush Sabharwal

    2009-07-01

    Two hydrogen production processes, both powered by a Next Generation Nuclear Plant (NGNP), are currently under investigation at Idaho National Laboratory. The first is high-temperature steam electrolysis, which uses both heat and electricity; the second is thermo-chemical production through the sulfur iodine process primarily using heat. Both processes require a high temperature (>850°C) for enhanced efficiency; temperatures indicative of the NGNP. Safety and licensing mandates prudently dictate that the NGNP and the hydrogen production facility be physically isolated, perhaps requiring separation of over 100 m.

  20. Effect of micro-roughness produced by TiO2 blasting--tensile testing of bone attachment by using coin-shaped implants.

    PubMed

    Rønold, Hans Jacob; Ellingsen, Jan Eirik

    2002-11-01

    The aim of the present study was to examine bone response to micro-rough titanium implants. Forty coin-shaped implants were divided into eight groups according to their surface roughness. The first group had electropolished surfaces. The surfaces of implant groups 2-8 were blasted with TiO2 particles with incremental grain sizes ranging from 7.5-12.5 to 270-330 microns. Five implants from each group were placed into the cortical bone of the proximal tibia in New Zealand Black rabbits. To avoid bone overgrowth during the retention phase the implants were fitted into tight polytetrafluoroethylene (PTFE) caps leaving only the flat test surface exposed to bone. The healing period was set to 10 weeks, and implants with attached bone were evaluated using a tensile testing machine. In groups 1-7 a significant correlation between the micro-roughness of the implant surfaces and retention strength was observed. Maximum bone bonding was observed with implants blasted with 180-220 microns grain size (group 7). Blasting with larger TiO2 particles appeared to decrease the effect. The findings suggest that the best grain size of TiO2 particles for optimising retention of titanium implants in cortical bone should be in the 180-220 microns range. PMID:12194524

  1. Effects of chemical composition and test conditions on the dynamic tensile response of Zr-based metallic glasses

    NASA Astrophysics Data System (ADS)

    Wang, F.; Laws, K. J.; Trujillo, C. P.; Brown, A. D.; Cerreta, E. K.; Hazell, P. J.; Quadir, M. Z.; Ferry, M.; Escobedo, J. P.

    2015-06-01

    The effects of impact velocity and temperature on the dynamic mechanical behavior of two bulk metallic glasses (BMG) with slightly different elemental compositions (Zr55Cu30Ni5Al30 and Zr46Cu38Ag8Al38) have been investigated. Bullet-shaped samples were accelerated by a gas gun to speeds in the 400 ~ 600m/s range and tested at room temperature and 250 °C. The specimens impacted a steel extrusion die which subjected them to high strains at high strain-rates. The extruded samples were subsequently soft recovered by using low density foams. The deformed specimens were examined by optical and electron microscopy, x-ray diffraction and hardness measurements. The characterization results aided to assess the effect of chemical composition on the microstructural evolution, i.e. phase changes or crystallization, which might influence the ductility on the nominally brittle amorphous BMGs. The most significant results from this study will be presented. School of Engineering and Information Technology, UNSW Canberra.

  2. Effect of thermomechanical processing on the microstructure and retained austenite stability during in situ tensile testing using synchrotron x-ray diffraction of NbMoAI TRIP steel.

    SciTech Connect

    Pereloma, E.; Zhang, L.; Liss, K.-D.; Garbe, U.; Almer, J.; Schambron, T.; Beladi, H.; Timokhina, I.

    2011-06-01

    In this work we compare and contrast the stability of retained austenite during tensile testing of Nb-Mo-Al transformation-induced plasticity steel subjected to different thermomechanical processing schedules. The obtained microstructures were characterised using optical metallography, transmission electron microscopy and X-ray diffraction. The transformation of retained austenite to martensite under tensile loading was observed by in-situ high energy X-ray diffraction at 1ID / APS. It has been shown that the variations in the microstructure of the steel, such as volume fractions of present phases, their morphology and dimensions, play a critical role in the strain-induced transition of retained austenite to martensite.

  3. Method and apparatus for determining tensile strength

    DOEpatents

    Ratigan, J.L.

    1982-05-28

    A method and apparatus is described for determining the statistical distribution of apparent tensile strength of rock, the size effect with respect to tensile strength, as well as apparent deformation modulus of both intact and fractured or jointed rock. The method is carried out by inserting a plug of deformable material, such as rubber, in an opening of a specimen to be tested. The deformable material is loaded by an upper and lower platen until the specimen ruptures, whereafter the tensile strength is calculated based on the parameters of the test specimen and apparatus.

  4. Method and apparatus for determining tensile strength

    DOEpatents

    Ratigan, Joe L.

    1984-01-01

    A method and apparatus for determining the statistical distribution of apparent tensile strength of rock, the size effect with respect to tensile strength, as well as apparent deformation modulus of both intact and fractured or jointed rock. The method is carried out by inserting a plug of deformable material, such as rubber, in an opening of a specimen to be tested. The deformable material is loaded by an upper and lower platen until the specimen ruptures, whereafter the tensile strength is calculated based on the parameters of the test specimen and apparatus.

  5. Corrosion and Creep of Candidate Alloys in High Temperature Helium and Steam Environments for the NGNP

    SciTech Connect

    Was, Gary; Jones, J. W.

    2013-06-21

    This project aims to understand the processes by which candidate materials degrade in He and supercritical water/steam environments characteristic of the current NGNP design. We will focus on understanding the roles of temperature, and carbon and oxygen potential in the 750-850 degree C range on both uniform oxidation and selective internal oxidation along grain boundaries in alloys 617 and 800H in supercritical water in the temperature range 500-600 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature rang 750-850 degree C; and examining the application of static and cyclic stresses in combination with impure He environments in the temperature range 750-850 degree C over a range of oxygen and carbon potentials in helium. Combined, these studies wil elucidate the potential high damage rate processes in environments and alloys relevant to the NGNP.

  6. NGNP Nuclear-Industrial Facility and Design Certification Boundaries White Paper

    SciTech Connect

    Thomas E. Hicks

    2011-07-01

    The Next Generation Nuclear Plant (NGNP) Project was initiated at Idaho National Laboratory by the U.S. Department of Energy pursuant to the 2005 Energy Policy Act and based on research and development activities supported by the Generation IV Nuclear Energy Systems Initiative. The principal objective of the NGNP Project is to support commercialization of the high temperature gas-cooled reactor (HTGR) technology. The HTGR is helium cooled and graphite moderated and can operate at reactor outlet temperatures much higher than those of conventional light water reactor (LWR) technologies. Accordingly, it can be applied in many industrial applications as a substitute for burning fossil fuels, such as natural gas, in addition to producing electricity, which is the principal application of current LWRs. These varied industrial applications may involve a standard HTGR modular design using different Energy Conversion Systems. Additionally, some of these process heat applications will require process heat delivery systems to lie partially outside the HTGR operator’s facility.

  7. Next Generation Nuclear Plant (NGNP) Prismatic HTGR Conceptual Design Project - Final Technical Report

    SciTech Connect

    Saurwein, John

    2011-07-15

    This report is the Final Technical Report for the Next Generation Nuclear Plant (NGNP) Prismatic HTGR Conceptual Design Project conducted by a team led by General Atomics under DOE Award DE-NE0000245. The primary overall objective of the project was to develop and document a conceptual design for the Steam Cycle Modular Helium Reactor (SC-MHR), which is the reactor concept proposed by General Atomics for the NGNP Demonstration Plant. The report summarizes the project activities over the entire funding period, compares the accomplishments with the goals and objectives of the project, and discusses the benefits of the work. The report provides complete listings of the products developed under the award and the key documents delivered to the DOE.

  8. NGNP: High Temperature Gas-Cooled Reactor Key Definitions, Plant Capabilities, and Assumptions

    SciTech Connect

    Wayne Moe

    2013-05-01

    This document provides key definitions, plant capabilities, and inputs and assumptions related to the Next Generation Nuclear Plant to be used in ongoing efforts related to the licensing and deployment of a high temperature gas-cooled reactor. These definitions, capabilities, and assumptions were extracted from a number of NGNP Project sources such as licensing related white papers, previously issued requirement documents, and preapplication interactions with the Nuclear Regulatory Commission (NRC).

  9. Progress Report for Diffusion Welding of the NGNP Process Application Heat Exchangers

    SciTech Connect

    R.E. Mizia; D.E. Clark; M.V. Glazoff; T.E. Lister; T.L. Trowbridge

    2011-04-01

    The NGNP Project is currently investigating the use of metallic, diffusion welded, compact heat exchangers to transfer heat from the primary (reactor side) heat transport system to the secondary heat transport system. The intermediate heat exchanger will transfer this heat to downstream applications such as hydrogen production, process heat, and electricity generation. The channeled plates that make up the heat transfer surfaces of the intermediate heat exchanger will have to be assembled into an array by diffusion welding.

  10. TRITIUM MOVEMENT AND ACCUMULATION IN THE NGNP SYSTEM INTERFACE AND HYDROGEN PLANT

    SciTech Connect

    Sherman, S

    2008-03-20

    Tritium movement and accumulation in the Next Generation Nuclear Plant (NGNP) employing either a high-temperature electrolysis (HTE) process or a thermochemical water-splitting Sulfur-Iodine (SI) process to produce hydrogen is estimated by a numerical code, THYTAN, as a function of design, operational and material parameters. Estimated tritium concentrations in the hydrogen product and in the process chemicals of the hydrogen plant using the HTE process are slightly higher than the limit in drinking water defined by the U.S. Environmental Protection Agency (EPA) and in effluent at the boundary of an unrestricted area defined by the U.S. Nuclear Regulatory Commission (NRC), respectively. Estimated tritium concentrations in the NGNP using the SI hydrogen production process are significantly higher, and are largely affected by undetermined parameters (i.e., tritium permeability of heat exchanger materials, hydrogen concentration in the helium energy transport fluids, equilibrium constant of the tritium isotope exchange reaction between HT and H{sub 2}SO{sub 4}). These parameters should be measured or estimated in the near future, as should the tritium generation and release rate from the NGNP nuclear reactor core. Decreasing the tritium permeation rate between the primary and secondary heat transport circuits is an effective measure to decrease the tritium concentrations in the hydrogen product, hydrogen plant process chemicals, and the tertiary heat transport fluid.

  11. Tensile and Fatigue Testing and Material Hardening Model Development for 508 LAS Base Metal and 316 SS Similar Metal Weld under In-air and PWR Primary Loop Water Conditions

    SciTech Connect

    Mohanty, Subhasish; Soppet, William; Majumdar, Saurin; Natesan, Ken

    2015-09-01

    This report provides an update on an assessment of environmentally assisted fatigue for light water reactor components under extended service conditions. This report is a deliverable in September 2015 under the work package for environmentally assisted fatigue under DOE’s Light Water Reactor Sustainability program. In an April 2015 report we presented a baseline mechanistic finite element model of a two-loop pressurized water reactor (PWR) for systemlevel heat transfer analysis and subsequent thermal-mechanical stress analysis and fatigue life estimation under reactor thermal-mechanical cycles. In the present report, we provide tensile and fatigue test data for 508 low-alloy steel (LAS) base metal, 508 LAS heat-affected zone metal in 508 LAS–316 stainless steel (SS) dissimilar metal welds, and 316 SS-316 SS similar metal welds. The test was conducted under different conditions such as in air at room temperature, in air at 300 oC, and under PWR primary loop water conditions. Data are provided on materials properties related to time-independent tensile tests and time-dependent cyclic tests, such as elastic modulus, elastic and offset strain yield limit stress, and linear and nonlinear kinematic hardening model parameters. The overall objective of this report is to provide guidance to estimate tensile/fatigue hardening parameters from test data. Also, the material models and parameters reported here can directly be used in commercially available finite element codes for fatigue and ratcheting evaluation of reactor components under in-air and PWR water conditions.

  12. Dynamic-tensile-extrusion response of fluoropolymers

    SciTech Connect

    Brown, Eric N; Trujillo, Carl P; Gray, George T

    2009-01-01

    The current work applies the recently developed Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) technique to polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE). Similar to the Taylor Impact Rod, Dynamic-Tensile-Extrusion is a strongly integrated test, probing a wide range of strain rates and stress states. However, the stress state is primarily tensile enabling investigation of dynamic tensile failure modes. Here we investigate the influence of this propensity to neck or not between PCTFE and PTFE on their response under dynamic tensile extrusion loading. The results of the Dyn-Ten-Ext technique are compared with two classic techniques. Both polymers have been investigated using Tensile Split Hopkinson Pressure Bar. The quasistatic and dynamic responses of both fluoro-polymers have been extensively characterized. The two polymers exhibit significantly different failure behavior under tensile loading at moderate strain rates. Polytetrafluoroethylene resists formation of a neck and exhibits significant strain hardening. Independent of temperature or strain rate, PTFE sustains true strains to failure of approximately 1.5. Polychlorotrifluoroethylene, on the other hand, consistently necks at true strains of approximately 0.05.

  13. Measurement error of Young’s modulus considering the gravity and thermal expansion of thin specimens for in situ tensile testing

    NASA Astrophysics Data System (ADS)

    Ma, Zhichao; Zhao, Hongwei; Ren, Luquan

    2016-06-01

    Most miniature in situ tensile devices compatible with scanning/transmission electron microscopes or optical microscopes adopt a horizontal layout. In order to analyze and calculate the measurement error of the tensile Young’s modulus, the effects of gravity and temperature changes, which would respectively lead to and intensify the bending deformation of thin specimens, are considered as influencing factors. On the basis of a decomposition method of static indeterminacy, equations of simplified deflection curves are obtained and, accordingly, the actual gage length is confirmed. By comparing the effects of uniaxial tensile load on the change of the deflection curve with gravity, the relation between the actual and directly measured tensile Young’s modulus is obtained. Furthermore, the quantitative effects of ideal gage length l o, temperature change ΔT and the density ρ of the specimen on the modulus difference and modulus ratio are calculated. Specimens with larger l o and ρ present more obvious measurement errors for Young’s modulus, but the effect of ΔT is not significant. The calculation method of Young’s modulus is particularly suitable for thin specimens.

  14. Tensile properties of nanoclay reinforced epoxy composites

    NASA Astrophysics Data System (ADS)

    Ku, H.; Trada, Mohan

    2013-08-01

    Kinetic epoxy resin was filled with nanoclay to increase tensile properties of the composite for civil and structural. This project manufactured samples with different percentages by weight of nanoclay in the composites in steps of 1 wt %, which were then post-cured in an oven. The samples were then subjected to tensile tests. The results showed that the composite with 3 wt % of nanoclay produced the highest yield and tensile strengths. However, the Young's modulus increased with increasing nanoparticulate loading. It is hoped that the discussion and results in this work would not only contribute towards the further development of nanoclay reinforced epoxy composites with enhanced material properties, but also provide useful information for the studies of fracture toughness, tensile properties and flexural properties of other composites.

  15. A novel approach to fabricating fuel compacts for the next generation nuclear plant (NGNP)

    NASA Astrophysics Data System (ADS)

    Pappano, P. J.; Burchell, T. D.; Hunn, J. D.; Trammell, M. P.

    2008-10-01

    The next generation nuclear plant (NGNP) is a combined complex of a very high temperature reactor (VHTR) and hydrogen production facility. The VHTR can have a prismatic or pebble bed design and is powered by TRISO fuel in the form of a fuel compact (prismatic) or pebble (pebble bed). The US is scheduled to build a demonstration VHTR at the Idaho National Laboratory site by 2020. The first step toward building of this facility is development and qualification of the fuel for the reactor. This paper summarizes the research and development efforts performed at Oak Ridge National Laboratory (ORNL) toward development of a qualified fuel compact for a VHTR.

  16. 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.

  17. Experimental Studies of NGNP Reactor Cavity Cooling System With Water

    SciTech Connect

    Corradini, Michael; Anderson, Mark; Hassan, Yassin; Tokuhiro, Akira

    2013-01-16

    This project will investigate the flow behavior that can occur in the reactor cavity cooling system (RCCS) with water coolant under the passive cooling-mode of operation. The team will conduct separate-effects tests and develop associated scaling analyses, and provide system-level phenomenological and computational models that describe key flow phenomena during RCCS operation, from forced to natural circulation, single-phase flow and two-phase flow and flashing. The project consists of the following tasks: Task 1. Conduct separate-effects, single-phase flow experiments and develop scaling analyses for comparison to system-level computational modeling for the RCCS standpipe design. A transition from forced to natural convection cooling occurs in the standpipe under accident conditions. These tests will measure global flow behavior and local flow velocities, as well as develop instrumentation for use in larger scale tests, thereby providing proper flow distribution among standpipes for decay heat removal. Task 2. Conduct separate-effects experiments for the RCCS standpipe design as two-phase flashing occurs and flow develops. As natural circulation cooling continues without an ultimate heat sink, water within the system will heat to temperatures approaching saturation , at which point two-phase flashing and flow will begin. The focus is to develop a phenomenological model from these tests that will describe the flashing and flow stability phenomena. In addition, one could determine the efficiency of phase separation in the RCCS storage tank as the two-phase flashing phenomena ensues and the storage tank vents the steam produced. Task 3. Develop a system-level computational model that will describe the overall RCCS behavior as it transitions from forced flow to natural circulation and eventual two-phase flow in the passive cooling-mode of operation. This modeling can then be used to test the phenomenological models developed as a function of scale.

  18. An experimental evaluation of the tensile strength of impact ice

    NASA Technical Reports Server (NTRS)

    Xian, X.; Chu, M. L.; Scavuzzo, R. J.; Srivatsan, T. S.

    1989-01-01

    The evaluation of the tensile strength of impact built-up ice on structural components has been prompted by such problems as electrical transmission line losses and catastrophic failures in Arctic regions, deicing problems with fixed-wing and rotary-wing aircraft, etc. It is demonstrated that the conventional tensile-testing technique furnishes adequate data on artificially refrigerated ice, and helps establish the influence of extrinsic factors on ice tensile strength.

  19. Tensile properties of textile composites

    NASA Technical Reports Server (NTRS)

    Avva, V. Sarma; Sadler, Robert L.; Lyon, Malcolm

    1992-01-01

    The importance of textile composite materials in aerospace structural applications has been gaining momentum in recent years. With a view to better understand the suitability of these materials in aerospace applications, an experimental program was undertaken to assess the mechanical properties of these materials. Specifically, the braided textile preforms were infiltrated with suitable polymeric matrices leading to the fabrication of composite test coupons. Evaluation of the tensile properties and the analyses of the results in the form of strength moduli, Poisson's ratio, etc., for the braided composites are presented. Based on our past experience with the textile coupons, the fabrication techniques have been modified (by incorporating glass microballoons in the matrix and/or by stabilizing the braid angle along the length of the specimen with axial fibers) to achieve enhanced mechanical properties of the textile composites. This paper outlines the preliminary experimental results obtained from testing these composites.

  20. Site Selection & Characterization Status Report for Next Generation Nuclear Plant (NGNP)

    SciTech Connect

    Mark Holbrook

    2007-09-01

    In the near future, the US Department of Energy (DOE) will need to make important decisions regarding design and construction of the Next Generation Nuclear Plant (NGNP). One part of making these decisions is considering the potential environmental impacts that this facility may have, if constructed here at the Idaho National Laboratory (INL). The National Environmental Policy Act (NEPA) of 1969 provides DOE decision makers with a process to systematically consider potential environmental consequences of agency decisions. In addition, the Energy Policy Act of 2005 (Title VI, Subtitel C, Section 644) states that the 'Nuclear Regulatory Commission (NRC) shall have licensing and regulatory authority for any reactor authorized under this subtitle.' This stipulates that the NRC will license the NGNP for operation. The NRC NEPA Regulations (10 CFR Part 51) require tha thte NRC prepare an Environmental Impact Statement (EIS) for a permit to construct a nuclear power plant. The applicant is required to submit an Environmental report (ER) to aid the NRC in complying with NEPA.

  1. Tensile and shear strength of adhesives

    NASA Technical Reports Server (NTRS)

    Stibolt, Kenneth A.

    1990-01-01

    This experiment is conducted in a freshman-level course: Introduction to Engineering Materials. There are no prerequisites for the course although students should have some knowledge of basic algebra. The objectives are to tension and shear test adhesives and to determine the tensile and shear properties of adhesives. Details of equipment of procedure are given.

  2. Tensile bond strength of repaired amalgam.

    PubMed

    Hadavi, F; Hey, J H; Czech, D; Ambrose, E R

    1992-03-01

    This study evaluated the tensile strength of repaired high-copper amalgams and analyzed the different treatments of the amalgam interface prior to repair. One hundred specimens were divided into 10 groups: group 1 was left intact and was considered as the control group. In groups 2 through 8, the specimens were sectioned into halves after 10 days and were reconstructed with new amalgam. Groups 9 and 10 were condensed with time intervals of 15 minutes and all specimens were subjected to tensile loads in a Universal Testing Machine. The tensile strengths at the junction between old and new amalgam ranged between 50% to 79% of those of the control group and verified that the same type of amalgam and uncontaminated interfaces had higher strengths. The results also suggested that if an amalgam repair is anticipated, additional retention is critical to the longevity of the restoration. PMID:1507091

  3. Mechanical shear and tensile characteristics of selected biomass stems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mechanical characteristics (stress and energy of tensile and shear modes) of selected biomass stems, such as big bluestem, bromegrass, and Barlow wheat were determined. A high capacity MTI-100K universal testing machine attached with standard tensile clamps and designed fabricated double-shear devic...

  4. Tensile strength and durability of bovine dentin.

    PubMed

    Inoue, Toshiko; Miyazaki, Takashi; Nishimura, Fumio

    2007-05-01

    This study investigated the effects of thermal cycling on the tensile strength of dentin. Bovine dentin were divided into 10 groups, which were then subjected to various conditions: intact after preparation, thereby serving as a control; heating in boiling water for 45 minutes; 10,000 thermal cycles in water; 10,000 thermal cycles in PBS; storage in water at 5, 23, or 55 degrees C for two weeks; and storage in PBS at 5, 23, or 55 degrees C for two weeks. Subsequently, bovine dentin were trimmed into dumbbell-shaped specimens and the tensile test performed in distilled water at 37 degrees C. Mean tensile strengths were compared statistically by one-way ANOVA and Fisher's PLTD test (p<0.05). Fracture surfaces were observed by scanning electron microscopy, and reliability of the results was analyzed with Weibull distribution. Tensile strength did not significantly change after thermal cycling or storage in water and PBS at all temperatures tested (71.2-77.0 MPa) but decreased after treatment with boiling water (65.5 MPa). PMID:17694743

  5. Dynamic Tensile Strength of Coal under Dry and Saturated Conditions

    NASA Astrophysics Data System (ADS)

    Zhao, Yixin; Liu, Shimin; Jiang, Yaodong; Wang, Kai; Huang, Yaqiong

    2016-05-01

    The tensile failure characterization of dry and saturated coals under different impact loading conditions was experimentally investigated using a Split Hopkinson pressure bar. Indirect dynamic Brazilian disc tension tests for coals were carried out. The indirect tensile strengths for different bedding angles under different impact velocities, strain rates and loading rates are analyzed and discussed. A high-speed high-resolution digital camera was employed to capture and record the dynamic failure process of coal specimens. Based on the experimental results, it was found that the saturated specimens have stronger loading rate dependence than the dry specimens. The bedding angle has a smaller effect on the dynamic indirect tensile strength compared to the impact velocity. Both shear and tensile failures were observed in the tested coal specimens. Saturated coal specimens have higher indirect tensile strength than dry ones.

  6. Heat exchanger temperature response for duty-cycle transients in the NGNP/HTE.

    SciTech Connect

    Vilim, R. B.; Nuclear Engineering Division

    2009-03-12

    Control system studies were performed for the Next Generation Nuclear Plant (NGNP) interfaced to the High Temperature Electrolysis (HTE) plant. Temperature change and associated thermal stresses are important factors in determining plant lifetime. In the NGNP the design objective of a 40 year lifetime for the Intermediate Heat Exchanger (IHX) in particular is seen as a challenge. A control system was designed to minimize temperature changes in the IHX and more generally at all high-temperature locations in the plant for duty-cycle transients. In the NGNP this includes structures at the reactor outlet and at the inlet to the turbine. This problem was approached by identifying those high-level factors that determine temperature rates of change. First are the set of duty cycle transients over which the control engineer has little control but which none-the-less must be addressed. Second is the partitioning of the temperature response into a quasi-static component and a transient component. These two components are largely independent of each other and when addressed as such greater understanding of temperature change mechanisms and how to deal with them is achieved. Third is the manner in which energy and mass flow rates are managed. Generally one aims for a temperature distribution that minimizes spatial non-uniformity of thermal expansion in a component with time. This is can be achieved by maintaining a fixed spatial temperature distribution in a component during transients. A general rule of thumb for heat exchangers is to maintain flow rate proportional to thermal power. Additionally the product of instantaneous flow rate and heat capacity should be maintained the same on both sides of the heat exchanger. Fourth inherent mechanisms for stable behavior should not be compromised by active controllers that can introduce new feedback paths and potentially create under-damped response. Applications of these principles to the development of a plant control strategy for

  7. Electrothermal fracturing of tensile specimens

    NASA Technical Reports Server (NTRS)

    Blinn, H. O.; Hanks, J. G.; Perkins, H. P.

    1970-01-01

    Pulling device consisting of structural tube, connecting rod, spring-loaded nuts, loading rod, heating element, and three bulkheads fractures tensile specimens. Alternate heating and cooling increases tensile loading by increments until fracturing occurs. Load cell or strain gage, applied to pulling rod, determines forces applied.

  8. Tensile Strength of Carbon/Carbon Composites

    NASA Astrophysics Data System (ADS)

    Hatta, Hiroshi; Aoi, Tatsuji; Kawahara, Itaru; Kogo, Yasuo; Shiota, Ichiro

    In order to identify ruling mechanisms of tensile fracture of Carbon/Carbon composites (C/Cs), tensile tests were carried out for various C/Cs as functions of the density, heat treatment temperature, and interfacial strength between fiber and matrix. Three processing routes of preformed yarn, resin char, and HIP processes were adopted to densify C/Cs. These C/Cs were finally heat-treated at temperatures from 2273K to 3300K. The interfacial strength between fiber and matrix was varied by the selection of processing routes. As a result, two ruling failure mechanisms were identified. At density lower than 1.6g/cm3, the tensile fracture was controlled by stress transfer capability from the matrix to reinforcing fibers. However, at higher density than 1.6g/cm3, tensile strength was primarily governed by the interfacial strength between the matrix and fibers. Thus the latter mechanism is nearly same as ceramic matrix composites.

  9. High temperature tensile properties of V-4Cr-4Ti

    SciTech Connect

    Zinkle, S.J.; Rowcliffe, A.F.; Stevens, C.O.

    1998-09-01

    Tensile tests have been performed on V-4Cr-4Ti at 750 and 800 C in order to extend the data base beyond the current limit of 700 C. From comparison with previous measurements, the yield strength is nearly constant and tensile elongations decrease slightly with increasing temperature between 300 and 800 C. The ultimate strength exhibits an apparent maximum near 600 C (attributable to dynamic strain aging) but adequate strength is maintained up to 800 C. The reduction in area measured on tensile specimens remained high ({approximately}80%) for test temperatures up to 800 C, in contrast to previous reported results.

  10. Preliminary assessment of existing experimental data for validation ofreactor physics codes and data for NGNP design and analysis.

    SciTech Connect

    Terry, W. K.; Jewell, J. K.; Briggs, J. B.; Taiwo, T. A.; Park, W.S.; Khalil, H. S.

    2005-10-25

    The Next Generation Nuclear Plant (NGNP), a demonstration reactor and hydrogen production facility proposed for construction at the INEEL, is expected to be a high-temperature gas-cooled reactor (HTGR). Computer codes used in design and safety analysis for the NGNP must be benchmarked against experimental data. The INEEL and ANL have examined information about several past and present experimental and prototypical facilities based on HTGR concepts to assess the potential of these facilities for use in this benchmarking effort. Both reactors and critical facilities applicable to pebble-bed and prismatic block-type cores have been considered. Four facilities--HTR-PROTEUS, HTR-10, ASTRA, and AVR--appear to have the greatest potential for use in benchmarking codes for pebble-bed reactors. Similarly, for the prismatic block-type reactor design, two experiments have been ranked as having the highest priority--HTTR and VHTRC.

  11. Tensile strength of dried gelcast green bodies

    SciTech Connect

    Nunn, S.D.; Omatete, O.O.; Walls, C.A.; Barker, D.L.

    1994-04-01

    Ceramic green bodies were prepared by three different techniques, dry pressing, slip casting, and gelcasting. The tensile strength of the green bodies was measured using a diametral compression test. It was found that the gelcast samples were from 2 to 20 times stronger than the conventionally formed green bodies. SEM examination of the gelcast samples revealed a homogeneous, brittle fracture surface indicating a very uniform distribution of the binder and excellent dispersion of the ceramic powder.

  12. Tensile buckling of advanced turboprops

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Aiello, R. A.

    1982-01-01

    Theoretical studies were conducted to determine analytically the tensile buckling of advanced propeller blades (turboprops) in centrifugal fields, as well as the effects of tensile buckling on other types of structural behavior, such as resonant frequencies and flutter. Theoretical studies were also conducted to establish the advantages of using high performance composite turboprops as compared to titanium. Results show that the vibration frequencies are not affected appreciably prior to 80 percent of the tensile speed. Some frequencies approach zero as the tensile buckling speed is approached. Composites provide a substantial advantage over titanium on a buckling speed to weight basis. Vibration modes change as the rotor speed is increased and substantial geometric coupling is present.

  13. Manufacturing of Plutonium Tensile Specimens

    SciTech Connect

    Knapp, Cameron M

    2012-08-01

    Details workflow conducted to manufacture high density alpha Plutonium tensile specimens to support Los Alamos National Laboratory's science campaigns. Introduces topics including the metallurgical challenge of Plutonium and the use of high performance super-computing to drive design. Addresses the utilization of Abaqus finite element analysis, programmable computer numerical controlled (CNC) machining, as well as glove box ergonomics and safety in order to design a process that will yield high quality Plutonium tensile specimens.

  14. An Interlaminar Tensile Strength Specimen

    NASA Technical Reports Server (NTRS)

    Martin, Roderick H.; Jackson, Wade C.

    1993-01-01

    This paper describes a technique to determine interlaminar tensile strength, sigma(sub 3c), of a fiber reinforced composite material using a curved beam. The specimen was a unidirectional curved beam, bent 90 deg, with straight arms. Attached to each arm was a hinged loading mechanism that was held by the grips of a tension testing machine. Geometry effects of the specimen, including the effects of loading arm length, inner radius, thickness, and width, were studied. The data sets fell into two categories: low strength corresponding to a macroscopic flaw related failure and high strength corresponding to a microscopic flaw related failure. From the data available, the specimen width and loading arm length had little effect on sigma(sub 3c). The inner radius was not expected to have a significant effect on sigma(sub 3c), but this conclusion could not be confirmed because of differences in laminate quality for each curve geometry. The thicker specimens had the lowest value of sigma(sub 3c) because of poor laminate quality.

  15. Initial Scaling Studies and Conceptual Thermal Fluids Experiments for the Prismatic NGNP Point Design

    SciTech Connect

    D. M. McEligot; G. E. McCreery

    2004-09-01

    The objective of this report is to document the initial high temperature gas reactor scaling studies and conceptual experiment design for gas flow and heat transfer. The general approach of the project is to develop new benchmark experiments for assessment in parallel with CFD and coupled CFD/ATHENA/RELAP5-3D calculations for the same geometry. Two aspects of the complex flow in an NGNP are being addressed: (1) flow and thermal mixing in the lower plenum ("hot streaking" issue) and (2) turbulence and resulting temperature distributions in reactor cooling channels ("hot channel" issue). Current prismatic NGNP concepts are being examined to identify their proposed flow conditions and geometries over the range from normal operation to decay heat removal in a pressurized cooldown. Approximate analyses are being applied to determine key non-dimensional parameters and their magnitudes over this operating range. For normal operation, the flow in the coolant channels can be considered to be dominant forced convection with slight transverse property variation. The flow in the lower plenum can locally be considered to be a situation of multiple buoyant jets into a confined density-stratified crossflow -- with obstructions. Experiments are needed for the combined features of the lower plenum flows. Missing from the typical jet experiments are interactions with nearby circular posts and with vertical posts in the vicinity of vertical walls - with near stagnant surroundings at one extreme and significant crossflow at the other. Two heat transfer experiments are being considered. One addresses the "hot channel" problem, if necessary. The second experiment will treat heated jets entering a model plenum. Unheated MIR (Matched-Index-of-Refraction) experiments are first steps when the geometry is complicated. One does not want to use a computational technique which will not even handle constant properties properly. The MIR experiment will simulate flow features of the paths of jets

  16. Tensile, Compression, Open-Hole Compression and Double Cantilever Beam Fracture Toughness Testing of Multiple NASA Langley Research Center Composite Materials

    NASA Technical Reports Server (NTRS)

    Adams, Donald F.

    1999-01-01

    The attached data summarizes the work performed by the Composite Materials Research Group at the University of Wyoming funded by the NASA LaRC Research Grant NAG-1-1294. The work consisted primarily of tension, compression, open-hole compression and double cantilever beam fracture toughness testing performed an a variety of NASA LaRC composite materials. Tests were performed at various environmental conditions and pre-conditioning requirements. The primary purpose of this work was to support the LaRC material development efforts. The data summaries are arranged in chronological order from oldest to newest.

  17. Tensile stiffness analysis on ocean dynamic power umbilical

    NASA Astrophysics Data System (ADS)

    Tang, Ming-gang; Yan, Jun; Wang, Ye; Yue, Qian-jin

    2014-04-01

    Tensile stiffness of ocean dynamic power umbilical is an important design parameter for functional implementation and structural safety. A column with radial stiffness which is wound by helical steel wires is constructed to predict the tensile stiffness value of umbilicals in the paper. The relationship between the tension and axial deformation is expressed analytically so the radial contraction of the column is achieved in the relationship by use of a simple finite element method. With an agreement between the theoretical prediction and the tension test results, the method is proved to be simple and efficient for the estimation of tensile stiffness of the ocean dynamic power umbilical.

  18. Tensile strength of bovine trabecular bone.

    PubMed

    Kaplan, S J; Hayes, W C; Stone, J L; Beaupré, G S

    1985-01-01

    Data on the tensile and compressive properties of trabecular bone are needed to define input parameters and failure criteria for modeling total joint replacements. To help resolve differences in reports comparing tensile and compressive properties of trabecular bone, we have developed new methods, based on porous foam technology, for tensile testing of fresh/frozen trabecular bone specimens. Using bovine trabecular bone from an isotropic region from the proximal humerus as a model material, we measured ultimate strengths in tension and compression for two groups of 24 specimens each. The average ultimate strength in tension was 7.6 +/- 2.2 (95% C.I.) MPa and in compression was 12.4 +/- 3.2 MPa. This difference was statistically significant (p = 0.013) and was not related to density differences between the test groups (p = 0.28). Strength was related by a power-law function of the local apparent density, but, even accounting for density influences, isotropic bovine trabecular bone exhibits significantly lower strengths in tension than in compression. PMID:4077868

  19. Tensile mechanical properties of human forearm tendons.

    PubMed

    Weber, J F; Agur, A M R; Fattah, A Y; Gordon, K D; Oliver, M L

    2015-09-01

    Previous studies of the mechanical properties of tendons in the upper limb have used embalmed specimens or sub-optimal methods of measurement. The aim of this study was to determine the biomechanical properties of all tendons from five fresh frozen cadaveric forearms using updated methodology. The cross-sectional area of tendons was accurately measured using a laser reflectance system. Tensile testing was done in a precision servo-hydraulic device with cryo-clamp fixation. We determined that the cross-sectional area of some tendons is variable and directly influences the calculated material properties; visual estimation of this is unreliable. Data trends illustrate that digital extensor tendons possess the greatest tensile strength and a higher Young's modulus than other tendon types. PMID:25940499

  20. Tritium Sequestration in Gen IV NGNP Gas Stream via Proton Conducting Ceramic Pumps

    SciTech Connect

    Chen, Fanglin Frank; Adams, Thad M.; Brinkman, Kyle; Reifsnider, Kenneth

    2011-09-30

    Several types of high-temperature proton conductors based on SrCeO3 and BaCeO3 have been systematically investigated in this project for tritium separation in NGNP applications. One obstacle for the field application is the chemical stability issues in the presence of steam and CO2 for these proton conductors. Several strategies to overcome such issues have been evaluated, including A site doping and B site co-doping method for perovskite-structured proton conductors. Novel zirconium-free proton conductors have also been developed with improved electrical conductivity and enhanced chemical stability. Novel catalytic materials for the proton-conducting separation membranes have been investigated. A tubular geometry proton-conducting membrane has been developed for the proton separation membranes. Total dose rate estimated from tritium decay (beta emission) under realistic membrane operating conditions, combined with electron irradiation experiments, indicates that proton ceramic materials possess the appropriate radiation stability for this application.

  1. Tensile properties of palladium-silver alloys with absorbed hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1975-01-01

    The alloys 90Pd-10Ag, 80Pd-20Ag, 70Pd-30Ag, 60Pd-40Ag, and 50Pd-50Ag containing absorbed hydrogen were tested in tension. The results show the tensile properties to be independent of the phase transition. Also, hydrogen in the lattice does not necessarily cause embrittlement or poor elongation. The changes in the tensile properties appear dependent on the electron to atom site ratio.

  2. Dynamic tensile strength of glass fiber reinforced pultruded composites

    SciTech Connect

    Dutta, P.K.; Kumar, M.M.; Hui, D.

    1994-12-31

    This paper discusses the stress-strain behavior, fracture strength, influence of low temperature, and energy absorption in the diametral tensile splitting fracturing of a Glass Fiber Reinforced Polymer Composite. Experiments were conducted at low-temperature in a thermal chamber installed on a servo-hydraulic universal testing machine. The tensile strength was determined by diametral compression of disc samples at 24, {minus}5 and {minus}40 C.

  3. Discrete Analysis of Clay Layer Tensile Strength

    NASA Astrophysics Data System (ADS)

    Lê, T. N. H.; Plé, O.; Villard, P.; Gotteland, P.; Gourc, J. P.

    2009-06-01

    The Discrete Element Method is used to investigate the tensile behaviour and cracks mechanisms of a clay material submitted to bending loading. It is the case of compacted clay liners in landfill cap cover application. Such as the soil tested in this study is plastic clay, the distinct elements model was calibrated with previous data results by taking into account cohesive properties. Various contact and cohesion laws are tested to show that the numerical model is able to reproduce the failure mechanism. Numerical results are extending to simulate a landfill cap cover.

  4. Hydraulically Driven Grips For Hot Tensile Specimens

    NASA Technical Reports Server (NTRS)

    Bird, R. Keith; Johnson, George W.

    1994-01-01

    Pair of grips for tensile and compressive test specimens operate at temperatures up to 1,500 degrees F. Grips include wedges holding specimen inside furnace, where heated to uniform temperature. Hydraulic pistons drive wedges, causing them to exert clamping force. Hydraulic pistons and hydraulic fluid remain outside furnace, at room temperature. Cooling water flows through parts of grips to reduce heat transferred to external components. Advantages over older devices for gripping specimens in high-temperature tests; no need to drill holes in specimens, maintains constant gripping force on specimens, and heated to same temperature as that of specimen without risk of heating hydraulic fluid and acuator components.

  5. Tensile properties of amorphous diamond films

    SciTech Connect

    Lavan, D.A.; Hohlfelder, R.J.; Sullivan, J.P.; Friedmann, T.A.; Mitchell, M.A.; Ashby, C.I.

    1999-12-02

    The strength and modulus of amorphous diamond, a new material for surface micromachined MEMS and sensors, was tested in uniaxial tension by pulling laterally with a flat tipped diamond in a nanoindenter. Several sample designs were attempted. Of those, only the single layer specimen with a 1 by 2 {micro}m gage cross section and a fixed end rigidly attached to the substrate was successful. Tensile load was calculated by resolving the measured lateral and normal forces into the applied tensile force and frictional losses. Displacement was corrected for machine compliance using the differential stiffness method. Post-mortem examination of the samples was performed to document the failure mode. The load-displacement data from those samples that failed in the gage section was converted to stress-strain curves using carefully measured gage cross section dimensions. Mean fracture strength was found to be 8.5 {+-} 1.4 GPa and the modulus was 831 {+-} 94 GPa. Tensile results are compared to hardness and modulus measurements made using a nanoindenter.

  6. Hydration dependent viscoelastic tensile behavior of cornea.

    PubMed

    Hatami-Marbini, Hamed

    2014-08-01

    The cornea is a protective transparent connective tissue covering the front of the eye. The standard uniaxial tensile experiments are among the most popular techniques for investigating biomechanical properties of the cornea. This experimental method characterizes the stress-strain response of corneal strips immersed in a bathing solution. In the present study, the important roles of corneal hydration on tensile viscoelastic properties were investigated. The thickness was used as a surrogate for hydration and uniaxial tensile experiments were performed on bovine corneal samples with four different average thickness (hydration), i.e., 1100 μm (4.87 mg water/mg dry tissue), 900 μm (4.13 mg water/mg dry tissue), 700 μm (3.20 mg water/mg dry tissue), and 500 μm (1.95 mg water/mg dry tissue). The samples were immersed in mineral oil in order to prevent their swelling during the experiments. A quasilinear viscoelastic (QLV) model was used to analyze the experimental measurements and determine viscoelastic material constants. It was observed that both maximum and equilibrium (relaxed) stresses were exponentially increased with decreasing tissue thickness (hydration). Furthermore, the QLV model successfully captured the corneal viscoelastic response with an average R (2) value greater than 0.99. Additional experiments were conducted in OBSS in order to confirm that these significant changes in viscoelastic properties were because of corneal hydration and not the bathing solution. The findings of this study suggest that extra care must be taken in interpreting the results of earlier uniaxial tensile testings and their correspondence to the corneal biomechanical properties. PMID:24668183

  7. Tensile properties of the human glenoid labrum

    PubMed Central

    Smith, C D; Masouros, S D; Hill, A M; Wallace, A L; Amis, A A; Bull, A M J

    2008-01-01

    Human fresh-frozen cadaveric glenoid labrae from 16 donors were harvested and ten of these had no gross degeneration. These ten were divided into eight equal circumferential sections. Each section was cut to produce test-samples from the core layer with a cross-section of 1 × 1 mm. Tensile testing was performed within a controlled environment unit at 37 ± 1 °C and 100% relative humidity. Each test-sample was precycled to a quasi-static state to alleviate the effects of deep-freezing, prior to final testing. The tangent modulus was calculated for each test-sample before and after a 5-min period of stress relaxation and at yield. The mean elastic modulus and yield stress of the glenoid labrum were 22.8 ± 11.4 and 2.5 ± 2.1 MPa, respectively. The anterosuperior portion had a lower elastic modulus and lower yield stress than the inferior portion (both P < 0.02). The pre-stress relaxation tangent modulus was significantly lower than the post-stress relaxation tangent modulus for all portions of the labrum. The glenoid labrum has similar tensile material properties to articular cartilage. Its elastic modulus varies around its circumference. This suggests that the labrum may encounter different forces at different positions. PMID:18031481

  8. Effect of temperature on tensile and creep characteristics of PRD49 fiber/epoxy composites

    NASA Technical Reports Server (NTRS)

    Hanson, M. P.

    1972-01-01

    Tensile and creep data of PRD49-1 and 3 fiber/epoxy-resin composites are presented. Tensile data were obtained from 20 to 477 K (-423 to 400 F). Tensile strengths and moduli were determined at selected temperatures. Creep data are presented for fiber composites at 297, 422 and 450 K (75, 300, and 350 F) for as long as 1000 hours at stress levels of approximately 50 and 80 percent of the ultimate tensile strength at 297 K (75 F). Details of tensile specimens and test procedures used in the investigation are presented.

  9. Effects of conventional welding and laser welding on the tensile strength, ultimate tensile strength and surface characteristics of two cobalt-chromium alloys: a comparative study.

    PubMed

    Madhan Kumar, Seenivasan; Sethumadhava, Jayesh Raghavendra; Anand Kumar, Vaidyanathan; Manita, Grover

    2012-06-01

    The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt-chromium alloy. Samples were prepared with two commercially available cobalt-chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scanning electron microscope to evaluate the surface characteristics at the welded site. Both on laser welding as well as on conventional welding technique, Diadur alloy samples showed lesser values when tested for tensile and ultimate tensile strength when compared to Wironium alloy samples. Under the scanning electron microscope, the laser welded joints show uniform welding and continuous molt pool all over the surface with less porosity than the conventionally welded joints. Laser welding is an advantageous method of connecting or repairing cast metal prosthetic frameworks. PMID:23858281

  10. Tensile Bond Strength of Latex-Modified Bonded Concrete Overlays

    NASA Astrophysics Data System (ADS)

    Dubois, Cameron; Ramseyer, Chris

    2010-10-01

    The tensile bond strength of bonded concrete overlays was tested using the in-situ pull-off method described in ASTM C 1583 with the goal of determining whether adding latex to the mix design increases bond strength. One slab of ductile concrete (f'c > 12,000 psi) was cast with one half tined, i.e. roughened, and one half steel-troweled, i.e. smooth. The slab surface was sectioned off and overlay mixtures containing different latex contents cast in each section. Partial cores were drilled perpendicular to the surface through the overlay into the substrate. A tensile loading device applied a direct tensile load to each specimen and the load was increased until failure occurred. The tensile bond strength was then calculated for comparison between the specimens.

  11. Theoretical Design of a Thermosyphon for Efficient Process Heat Removal from Next Generation Nuclear Plant (NGNP) for Production of Hydrogen

    SciTech Connect

    Piyush Sabharwall; Fred Gunnerson; Akira Tokuhiro; Vivek Utgiker; Kevan Weaver; Steven Sherman

    2007-10-01

    The work reported here is the preliminary analysis of two-phase Thermosyphon heat transfer performance with various alkali metals. Thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. Heat transport occurs via evaporation and condensation, and the heat transport fluid is re-circulated by gravitational force. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. For process heat, intermediate heat exchangers (IHX) are required to transfer heat from the NGNP to the hydrogen plant in the most efficient way possible. The production of power at higher efficiency using Brayton Cycle, and hydrogen production requires both heat at higher temperatures (up to 1000oC) and high effectiveness compact heat exchangers to transfer heat to either the power or process cycle. The purpose for selecting a compact heat exchanger is to maximize the heat transfer surface area per volume of heat exchanger; this has the benefit of reducing heat exchanger size and heat losses. The IHX design requirements are governed by the allowable temperature drop between the outlet of the NGNP (900oC, based on the current capabilities of NGNP), and the temperatures in the hydrogen production plant. Spiral Heat Exchangers (SHE’s) have superior heat transfer characteristics, and are less susceptible to fouling. Further, heat losses to surroundings are minimized because of its compact configuration. SHEs have never been examined for phase-change heat transfer applications. The research presented provides useful information for thermosyphon design and Spiral Heat Exchanger.

  12. Theoretical Design of Thermosyphon for Process Heat Transfer from NGNP to Hydrogen Plant

    SciTech Connect

    Piyush Sabharwall; Mike Patterson; Fred Gunnerson

    2008-09-01

    The Next Generation Nuclear Plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to ~ 1300K) and industrial scale power transport (=50 MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization / condensing process. The condensate is further returned to the hot source by gravity, i.e. without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) or vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.

  13. Dynamic tensile properties of human placenta.

    PubMed

    Manoogian, Sarah J; Bisplinghoff, Jill A; McNally, Craig; Kemper, Andrew R; Santago, Anthony C; Duma, Stefan M

    2008-12-01

    Automobile crashes are the largest cause of injury death for pregnant females and the leading cause of traumatic fetal injury mortality in the United States. Computational models, useful tools to evaluate the risk of fetal loss in motor vehicle crashes, are based on a limited number of quasi-static material tests of the placenta. This study presents a total of 20 dynamic uniaxial tensile tests on the maternal side of the placenta and 10 dynamic uniaxial tensile tests on the chorion layer of the placenta. These tests were completed from 6 human placentas to determine material properties at a strain rate of 7.0 strains/s. The results show that the average peak strain at failure for both the maternal portion and the chorion layer of the placenta are similar with a value of 0.56 and 0.61, respectively. However, the average failure stress for the chorion layer, 167.8 kPa, is much higher than the average failure stress for the placenta with the chorionic plate removed, 18.6 kPa. This is due to differences in the structure and function of these layers in the placenta. In summary, dynamic loading data for the placenta have been determined for use in computational modeling of pregnant occupant kinematics in motor vehicle crashes. Moreover the computational model should utilize the material properties for the placenta without the chorion layer. PMID:18996533

  14. Specimen for high-temperature tensile tests

    NASA Technical Reports Server (NTRS)

    Coulbert, C. D.

    1972-01-01

    Split nut with internal taper to hold specially formed specimen composed of filaments of refractory material provides means for holding at high temperature and under tension so that performance evaluations may be made.

  15. Hot tensile tests of Inconel 718

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The physical metallurgy of near-solidus integranular cracking in Inconel 718 welds was investigated. The data, although inconclusive, suggest at least two mechanisms which might explain intergranular cracking (microfissuring) in the heat-affected zone of several high temperature alloys. One theory is based on the separation of intergranular liquid while the other involves mechanical failure of solid ligaments surrounded by intergranular liquid. Both mechanisms concentrate strain in the grain boundaries resulting in low strain (1%) intergranular brittleness. The mechanisms reported might also pertain to the physical metallurgy of casting, powder metallurgy sintering and hot isostatic pressing.

  16. Effect of Tensile Stress on Cavitation Erosion and Damage of Polymer

    NASA Astrophysics Data System (ADS)

    Hibi, M.; Inaba, K.; Takahashi, K.; Kishimoto, K.; Hayabusa, K.

    2015-12-01

    Cavitation erosion tests for epoxy, unsaturated polyester, polycarbonate, and acrylic resin were conducted under various tensile stress conditions (Tensile-Cavitation test). A new testing device was designed to conduct the Tensile-Cavitation test and observe specimen surface during the experiment based on ASTM G32. When tensile stress of 1.31 MPa was loaded on epoxy resin, cracks occurred on the specimen after 0.5 hours during cavitation erosion. When no tensile stress was loaded on the epoxy resin, the damage was general cavitation erosion only. As well as the epoxy resin, unsaturated polyester resin applied tensile stress of 1.31 MPa and polycarbonate resin of 6.54 MPa indicated erosion damages and cracks. When tensile stress of 6.54 MPa was loaded on acrylic resin, the erosion damage was almost the same as the results without tensile stress. We confirmed that anti-cavitation property of epoxy resin was higher than those of acrylic and polycarbonate without tensile stress while the damage of epoxy resin was much serious than that of acrylic resins under tensile stress loadings.

  17. Actuator Exerts Tensile Or Compressive Axial Load

    NASA Technical Reports Server (NTRS)

    Nozzi, John; Richards, Cuyler H.

    1994-01-01

    Compact, manually operated mechanical actuator applies controlled, limited tensile or compressive axial force. Designed to apply loads to bearings during wear tests in clean room. Intended to replace hydraulic actuator. Actuator rests on stand and imparts axial force to part attached to clevis inside or below stand. Technician turns control screw at one end of lever. Depending on direction of rotation of control screw, its end of lever driven downward (for compression) or upward (for tension). Lever pivots about clevis pin at end opposite of control screw; motion drives downward or upward link attached via shearpin at middle of lever. Link drives coupling and, through it, clevis attached to part loaded.

  18. Characterization of Damage in Triaxial Braid Composites Under Tensile Loading

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Binienda, Wieslaw K.; Roberts, Gary D.; Goldberg, Robert K.

    2009-01-01

    Carbon fiber composites utilizing flattened, large tow yarns in woven or braided forms are being used in many aerospace applications. Their complex fiber architecture and large unit cell size present challenges in both understanding deformation processes and measuring reliable material properties. This report examines composites made using flattened 12k and 24k standard modulus carbon fiber yarns in a 0 /+60 /-60 triaxial braid architecture. Standard straight-sided tensile coupons are tested with the 0 axial braid fibers either parallel with or perpendicular to the applied tensile load (axial or transverse tensile test, respectively). Nonuniform surface strain resulting from the triaxial braid architecture is examined using photogrammetry. Local regions of high strain concentration are examined to identify where failure initiates and to determine the local strain at the time of initiation. Splitting within fiber bundles is the first failure mode observed at low to intermediate strains. For axial tensile tests splitting is primarily in the 60 bias fibers, which were oriented 60 to the applied load. At higher strains, out-of-plane deformation associated with localized delamination between fiber bundles or damage within fiber bundles is observed. For transverse tensile tests, the splitting is primarily in the 0 axial fibers, which were oriented transverse to the applied load. The initiation and accumulation of local damage causes the global transverse stress-strain curves to become nonlinear and causes failure to occur at a reduced ultimate strain. Extensive delamination at the specimen edges is also observed.

  19. 7 CFR 29.3061 - Strength (tensile).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Strength (tensile). 29.3061 Section 29.3061... Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important element of quality in Burley tobacco....

  20. 7 CFR 29.3061 - Strength (tensile).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strength (tensile). 29.3061 Section 29.3061... Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important element of quality in Burley tobacco....

  1. 7 CFR 29.3061 - Strength (tensile).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Strength (tensile). 29.3061 Section 29.3061... Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important element of quality in Burley tobacco....

  2. 7 CFR 29.3061 - Strength (tensile).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Strength (tensile). 29.3061 Section 29.3061... Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important element of quality in Burley tobacco....

  3. 7 CFR 29.3061 - Strength (tensile).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Strength (tensile). 29.3061 Section 29.3061... Type 93) § 29.3061 Strength (tensile). The stress a tobacco leaf can bear without tearing. Tensile strength is not an important element of quality in Burley tobacco....

  4. NGNP/HTE full-power operation at reduced high-temperature heat exchanger temperatures.

    SciTech Connect

    VIlim, R.; Nuclear Engineering Division

    2009-03-12

    Operation of the Next Generation Nuclear Plant (NGNP) with reduced reactor outlet temperature at full power was investigated for the High Temperature Electrolysis (HTE) hydrogen-production application. The foremost challenge for operation at design temperature is achieving an acceptably long service life for heat exchangers. In both the Intermediate Heat Exchanger (IHX) and the Process Heat Exchanger (PHX) (referred to collectively as high temperature heat exchangers) a pressure differential of several MPa exists with temperatures at or above 850 C. Thermal creep of the heat exchanger channel wall may severely limit heat exchanger life depending on the alloy selected. This report investigates plant performance with IHX temperatures reduced by lowering reactor outlet temperature. The objective is to lower the temperature in heat transfer channels to the point where existing materials can meet the 40 year lifetime needed for this component. A conservative estimate for this temperature is believed to be about 700 C. The reactor outlet temperature was reduced from 850 C to 700 C while maintaining reactor power at 600 MWt and high pressure compressor outlet at 7 MPa. We included a previously reported design option for reducing temperature at the PHX. Heat exchanger lengths were adjusted to reflect the change in performance resulting from coolant property changes and from resizing related to operating-point change. Turbomachine parameters were also optimized for the new operating condition. An integrated optimization of the complete system including heat transfer equipment was not performed. It is estimated, however, that by performing a pinch analysis the combined plant efficiency can be increased from 35.5 percent obtained in this report to a value between 38.5 and 40.1 percent. Then after normalizing for a more than three percent decrease in commodities inventory compared to the reference plant, the commodities-normalized efficiency lies between 40.0 and 41.3. This

  5. Correlation of infrared thermographic patterns and acoustic emission signals with tensile deformation and fracture processes

    NASA Astrophysics Data System (ADS)

    Venkataraman, B.; Raj, Baldev; Mukhopadhyay, C. K.; Jayakumar, T.

    2001-04-01

    During tensile deformation, part of the mechanical work done on the specimen is transformed into heat and acoustic activity. The amount of acoustic activity and the thermal emissions depend on the test conditions and the deformation behavior of the specimen during loading. Authors have used thermography and acoustic emission (AE) simultaneously for monitoring tensile deformation in AISI type 316 SS. Tensile testing was carried out at 298 K at three different strain rates. It has been shown that the simultaneous use of these techniques can provide complementary information for characterizing the tensile deformation and fracture processes.

  6. Effects of bathing solution on tensile properties of the cornea.

    PubMed

    Hatami-Marbini, Hamed; Rahimi, Abdolrasol

    2014-03-01

    The cornea is a transparent tissue with the major functions of protecting the inner contents of the eye and refracting incoming light. The biomechanical properties of the cornea strongly depend on the microstructure and composition of the stromal layer, a hydrated bio-gel. The uniaxial strip testing is a convenient and well-accepted experimental technique for characterizing corneal material parameters. It is known that the water content of specimens in this method depends on the osmolality of the bathing solution. The present study was designed to investigate the effects of different bathing solutions on uniaxial tensile material properties of the cornea. The tensile behavior of bovine corneal samples was measured in six different bathing solutions, i.e., hypertonic solution (12% NaCl solution), common preserving isotonic solutions (e.g., phosphate buffer saline, ophthalmic balanced salt solution, and 0.9% NaCl solution), hypotonic solution (distilled water), and neutral solution (mineral oil). It was observed that the bathing solution had significant influence on the tensile behavior of the corneal samples. In particular, the specimens tested in bathing solutions causing less swelling had significantly stiffer tensile properties. Furthermore, a simple mathematical model based on Voigt composite material model was developed to represent the measured solution-dependent tensile properties. The present study suggests that extra attention should be paid to corneal thickness (hydration) in uniaxial tensile experiments. It also provides important data on tensile properties of the cornea; such information could significantly contribute to improving the accuracy of numerical predictions of corneal biomechanics. PMID:24333541

  7. Tensile-strength apparatus applies high strain-rate loading with minimum shock

    NASA Technical Reports Server (NTRS)

    Cotrill, H. E., Jr.; Mac Glashan, W. F., Jr.

    1966-01-01

    Tensile-strength testing apparatus employs a capillary bundle through which a noncompressible fluid is extruded and a quick-release valve system. This apparatus applies the test loads at relatively constant very high strain rates with minimal shock and vibration to the tensile specimen and apparatus.

  8. The tensile strength properties of CFRPs and GRRPs for Unnes electric car body material

    NASA Astrophysics Data System (ADS)

    Khumaedi, Muhammad; Sumbodo, Wirawan; Widodo, Rahmat Doni

    2016-04-01

    This paper describes composite materials tensile testing of electric car body material. The UNNES electric car body must be developed using a high strength and lightweight material. A fiber-reinforced plastic composite is widely used for the concerned objective. Selection of the type of composites, variations in fiber orientation, and the number of fiber layers will affect the tensile strength of the material. Composite materials use Carbon-fiber-reinforced plastics (CFRPs) and glass-fiber-reinforced plastics (GFRPs) variation to the fiber areal weight, variations in fiber orientation and the number of fiber layers. The CFRPs areal weight consists of 230 gsm and 400 gsm. The GFRPsareal weight consists of 400 gsm and 600 gsm. Fibre orientationsconsist of 0° and 45°. Number of fiber layers consists of one layer and two layers. Various variations were then tested to figure out their tensile to get ultimate tensile strength of materials. Standard test method for tensile test was conducted using ASTM D3039. Tensile specimen geometry used a type of balanced and symmetric fiber orientation, with 25mm in width, 250 mm in length, and 2.5 mm in thickness. The result shows that the more fiber areal weight and the layer number were used, the more its tensile strength would increase, beside it increased the ultimate tensile strength of the material for both glass and carbon fiber with 0o and 45o fiber arientation. Fiber plain wave with 45o has greater tensile strength compared to any other variation.

  9. Tensile behavior of irradiated SiC fibers

    SciTech Connect

    Osborne, M.C.; Steiner, D.; Snead, L.L.

    1994-09-01

    Tensile results are presented for low oxygen Nicalon fibers neutron irradiated at damage levels of 0.013 displacements per atom (dpa), 0.13 dpa and 0.32 dpa. Single fibers were tensile tested and analyzed, using Weibull statistics, for mean strength and distribution. Tensile modulus was also determined. Using a diffractometer, the fiber grain size and percent crystallinity were determined. The mean strength and modulus decreased by 20% but then increased with the highest damage level tested. Both grain size and crystallinity decreased as dose increased. These initial results of low level neutron irradiation of low oxygen Nicalon fibers exhibit no substantial degradation of the properties investigated. Therefore, continued research at higher doses is recommended.

  10. Tensile strength of cementitious materials under triaxial loading

    NASA Astrophysics Data System (ADS)

    Tsubota, Shuji

    1998-11-01

    A general tension-compression-compression (sigmasb1, sigmasb2=sigmasb3) failure criterion for brittle materials is mathematically developed using FEM analysis and experimentally verified by use of the cementitious composite axial tensile test (CCATT). This tensile failure criterion is based on the stress concentration derived from the classical theory of elasticity. This analytical approach shows the upper bound of the tension-compression-compression failure surface for brittle materials. Since the CCATT applies confining hydraulic pressure, a tensile specimen is subjected to triaxial loading defined by the principal stress ratio sigmasb1/|sigmasb2|. When lateral pressure increases, tensile strength decreases; therefore, stress concentration is defined as a function of the principal stress ratio. The model has three distinct regions of behavior corresponding to the principal stress ratio, 0≤sigmasb1/|sigmasb2|<0.9 (high-lateral pressure), 0.9≤sigmasb1/|sigmasb2|<3.0 (medium-lateral pressure), 3.0≤sigmasb1/|sigmasb2| (low-lateral pressure). The experimental failure line shows true tensile strength of cementitious materials under low-lateral pressure. The predicted nominal stress fsb{ta} with large size specimens for the CCATT is written as$fsb{ta}=gamma*{1/{Kt}}*alpha* pwhere gamma$ is the size effect obtained by experimental results; Kt is the stress concentration factor derived from triaxial loading. Tensile strength values from the CCATT are compared to experimental results from other tests such as the uniaxial tensile test and the split cylinder test. CCATT results are analyzed using Weibull theory to measure material reliability and to develop characteristic stresses for construction design. Failure analysis using fractography was conducted on fractured cementitious materials and composites. The failure analysis on test specimens correlated well with FEM stress distributions and with the principal stress ratio. The observed fracture behavior (fracture

  11. Tensile Properties of GRCop-84

    NASA Technical Reports Server (NTRS)

    Ellis, David L.; Loewenthal, William S.; Yun, Hee-Man

    2012-01-01

    This is a chapter in the final report on GRCop-84 for the Reusable Launch Vehicle (RLV) Second Generation/Project Constellation Program. It contains information on the tensile properties of GRCop-84. GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) was produced by extrusion and Hot Isostatic Pressing (HIPing). Some of the extrusions were rolled to plate and sheet while other extrusions were drawn into tubing. The material was further subjected to various heat treatments corresponding to annealing, anticipated typical brazing conditions, an end-of-life condition and various elevated temperature exposures to attempt to improve creep resistance. As anticipated, cold work increased strength while decreasing ductility. Annealing at 600 C (1112 F) and higher temperatures was effective. An exposure for 100 h at 500 C (932 F) resulted in an increase in strength rather than the anticipated decrease. High temperature simulated-braze cycles and thermal exposures lowered the strength of GRCop-84, but the deceases were small compared to precipitation strengthened copper alloys. It was observed that the excess Cr could form large precipitates that lower the reduction in area though it appears a minimum amount is required. Overall, GRCop-84 exhibits good stability of its tensile properties, which makes it an excellent candidate for rocket engine liners and many other high temperature applications.

  12. Ideal tensile strength of B2 transition-metal aluminides

    NASA Astrophysics Data System (ADS)

    Li, Tianshu; Morris, J. W., Jr.; Chrzan, D. C.

    2004-08-01

    The ideal tensile strengths of the B2 -type (CsCl) transition-metal aluminides FeAl , CoAl , and NiAl have been investigated using an ab initio electronic structure total energy method. The three materials exhibit dissimilar mechanical behaviors under the simulated ideal tensile tests along [001], [110], and [111] directions. FeAl is weakest in tension along [001] whereas CoAl and NiAl are strongest in the same direction. The weakness of FeAl along [001] direction is attributed to the instability introduced by the filling of antibonding d states.

  13. Tensile and compressive behavior of a swirl mat composite

    SciTech Connect

    Ruggles, M.B.

    1998-07-01

    The Durability of Lightweight Composite Structures Project was established at Oak Ridge National Laboratory (ORNL) by the US Department of Energy to provide the experimentally-based, durability-driven design guidelines necessary to assure long-term structural integrity of automotive composite components. The initial focus of the ORNL Durability Project was on one representative reference material--an isocyanurate (polyurethane) reinforced with continuous strand, swirl-mat E-glass. The present report describes tensile and compressive testing and results for the reference composite. Behavior trends and proportional limit are established for both tension and compression. Damage development due to tensile loading and strain rate effects are discussed.

  14. Effect of Strain Rate on Tensile Properties of Carbon Fiber Epoxy-Impregnated Bundle Composite

    NASA Astrophysics Data System (ADS)

    Naito, Kimiyoshi

    2014-03-01

    The tensile tests for high tensile strength polyacrylonitrile (PAN)-based (T1000GB) carbon fiber epoxy-impregnated bundle composite at various strain rates ranging from 3.33 × 10-5 to 6.0 × 102 s-1 (various crosshead speeds ranging from 8.33 × 10-7 to 1.5 × 101 m/s) were investigated. The statistical distributions of the tensile strength were also evaluated. The results clearly demonstrated that the tensile strength of bundle composite slightly increased with an increase in the strain rate (crosshead speed) and the Weibull modulus of tensile strength for the bundle composite decreased with an increase in the strain rate (crosshead speed), there is a linear relation between the Weibull modulus and the average tensile strength on log-log scale.

  15. Tensile and fatigue properties of Inconel 718 at cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Malin, C. O.; Schmidt, E. H.

    1969-01-01

    Tests to determine the tensile and fatigue properties of Inconel 718 at cryogenic temperatures show that the alloy increases in strength at low temperatures, with very little change in toughness. The effect of surface finish and grain size on the fatigue properties was also determined.

  16. Tensile and creep data on type 316 stainless steel

    SciTech Connect

    Sikka, V. K.; Booker, B. L.P.; Booker, M. K.; McEnerney, J. W.

    1980-01-01

    This report summarizes tensile and creep data on 13 heats of type 316 stainless steel. It includes ten different product forms (three plates, four pipes, and three bars) of the reference heat tested at ORNL. Tensile data are presented in tabular form and analyzed as a function of temperature by the heat centering method. This method yielded a measure of variations within a single heat as well as among different heats. The upper and lower scatter bands developed by this method were wider at the lower temperatures than at the high temperatures (for strength properties), a trend reflected by the experimental data. The creep data on both unaged and aged specimens are presented in tabular form along with creep curves for each test. The rupture time data are compared with the ASME Code Case minimum curve at each test temperature in the range from 538 to 704{sup 0}C. The experimental rupture time data are also compared with the values predicted by using the rupture model based on elevated-temperature ultimate tensile strength. A creep ductility trend curve was developed on the basis of the reference heat data and those published in the literature on nitrogen effects. To characterize the data fully, information was also supplied on vendor, product form, fabrication method, material condition (mill-annealed vs laboratory annealed and aged), grain size, and chemical composition for various heats. Test procedures used for tensile and creep results are also discussed.

  17. Static and fatigue interlaminar tensile characterization of laminated composites

    SciTech Connect

    Koudela, K.L.; Strait, L.H.; Caiazzo, A.A.; Gipple, K.L.

    1997-12-31

    Spool and curved-beam specimens were evaluated to determine the viability of using either one or both of these configurations to characterize the static and fatigue interlaminar tensile behavior of carbon/epoxy laminates. Unidirectional curved-beam and quasi-isotropic spool specimens were fabricated, nondestructively inspected, and statically tested to failure. Tension-tension fatigue tests were conducted at 10 Hz and an R-ratio ({sigma}{sub min}/{sigma}{sub max}) equal to 0.1 for each specimen configuration. The interlaminar tensile strength of the spool specimen was 12% larger than the strength obtained using curved-beam specimens. In addition, data scatter associated with spool specimens was significantly less than the scatter associated with curved-beam specimens. The difference in data scatter was attributed to the influence of the fabrication process on the quality of the laminates tested. The fatigue limit at 0{sup 7} cycles for both specimen types was shown to be at least 40% of the average interlaminar tensile strength. Based on the results of this study, it was concluded that either the spool or the curved-beam specimens can be used to characterize the interlaminar tensile static and fatigue behavior of carbon/epoxy laminates. However, to obtain the most representative results, the test specimen configuration should be selected so that the specimen fabrication process closely simulates the actual component fabrication process.

  18. NGNP Point Design - Results of the Initial Neutronics and Thermal-Hydraulic Assessments During FY-03, Rev. 1

    SciTech Connect

    Philip E. MacDonald; James W. Sterbentz; Robert L. Sant; P. Bayless; H. D. Gougar; R. L. Moore; A. M. Ougouag; W. K. Terry

    2003-09-01

    This report presents the preliminary preconceptual designs for two possible versions of the Next Generation Nuclear Plant (NGNP), one for a prismatic fuel type helium gas-cooled reactor and one for a pebble bed fuel helium gas reactor. Both designs are to meet three basic requirements: a coolant outlet temperature of 1000 °C, passive safety, and a total power output consistent with that expected for commercial high-temperature gas-cooled reactors. The two efforts are discussed separately below. The analytical results presented in this report are very promising, however, we wish to caution the reader that future, more detailed, design work will be needed to provide final answers to a number of key questions including the allowable power level, the inlet temperature, the power density, the optimum fuel form, and others. The point design work presented in this report provides a starting point for other evaluations, and directions for the detailed design, but not final answers.

  19. 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.

  20. Multi-Scale Multi-physics Methods Development for the Calculation of Hot-Spots in the NGNP

    SciTech Connect

    Downar, Thomas; Seker, Volkan

    2013-04-30

    Radioactive gaseous fission products are released out of the fuel element at a significantly higher rate when the fuel temperature exceeds 1600°C in high-temperature gas-cooled reactors (HTGRs). Therefore, it is of paramount importance to accurately predict the peak fuel temperature during all operational and design-basis accident conditions. The current methods used to predict the peak fuel temperature in HTGRs, such as the Next-Generation Nuclear Plant (NGNP), estimate the average fuel temperature in a computational mesh modeling hundreds of fuel pebbles or a fuel assembly in a pebble-bed reactor (PBR) or prismatic block type reactor (PMR), respectively. Experiments conducted in operating HTGRs indicate considerable uncertainty in the current methods and correlations used to predict actual temperatures. The objective of this project is to improve the accuracy in the prediction of local "hot" spots by developing multi-scale, multi-physics methods and implementing them within the framework of established codes used for NGNP analysis.The multi-scale approach which this project will implement begins with defining suitable scales for a physical and mathematical model and then deriving and applying the appropriate boundary conditions between scales. The macro scale is the greatest length that describes the entire reactor, whereas the meso scale models only a fuel block in a prismatic reactor and ten to hundreds of pebbles in a pebble bed reactor. The smallest scale is the micro scale--the level of a fuel kernel of the pebble in a PBR and fuel compact in a PMR--which needs to be resolved in order to calculate the peak temperature in a fuel kernel.

  1. On the tensile strength of insect swarms.

    PubMed

    Ni, Rui; Ouellette, Nicholas T

    2016-01-01

    Collective animal groups are often described by the macroscopic patterns they form. Such global patterns, however, convey limited information about the nature of the aggregation as a whole. Here, we take a different approach, drawing on ideas from materials testing to probe the macroscopic mechanical properties of mating swarms of the non-biting midge Chironomus riparius. By manipulating ground-based visual features that tend to position the swarms in space, we apply an effective tensile load to the swarms, and show that we can quasi-statically pull single swarms apart into multiple daughter swarms. Our results suggest that swarms surprisingly have macroscopic mechanical properties similar to solids, including a finite Young's modulus and yield strength, and that they do not flow like viscous fluids. PMID:27559838

  2. Tensile creep behavior of polycrystalline alumina fibers

    NASA Technical Reports Server (NTRS)

    Yun, H. M.; Goldsby, J. C.

    1993-01-01

    Tensile creep studies were conducted on polycrystalline Nextel 610 and Fiber FP alumina fibers with grain sizes of 100 and 300 nm, respectively. Test conditions were temperatures from 800 to 1050 C and stresses from 60 to 1000 MPa. For both fibers, only a small primary creep portion occurred followed by steady-state creep. The stress exponents for steady-state creep of Nextel 610 and Fiber FP were found to be about 3 and 1, respectively. At lower temperatures, below 1000 C, the finer grained Nextel 610 had a much higher 0.2 percent creep strength for 100 hr than the Fiber FP; while at higher temperatures, Nextel 610 had a comparable creep strength to the Fiber FP. The stress and grain size dependencies suggest Nextel 610 and Fiber FP creep rates are due to grain boundary sliding controlled by interface reaction and Nabarro-Herring mechanisms, respectively.

  3. 49 CFR Appendix A to Subpart C of... - Illustrations: Cylinder Tensile Sample

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Illustrations: Cylinder Tensile Sample A Appendix... Part 178—Illustrations: Cylinder Tensile Sample The following figures illustrate the recommended locations for test specimens taken from welded cylinders: ER08AU02.013 ER08AU02.014 ER08AU02.015...

  4. 49 CFR Appendix A to Subpart C of... - Illustrations: Cylinder Tensile Sample

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Illustrations: Cylinder Tensile Sample A Appendix... Part 178—Illustrations: Cylinder Tensile Sample The following figures illustrate the recommended locations for test specimens taken from welded cylinders: ER08AU02.013 ER08AU02.014 ER08AU02.015...

  5. 49 CFR Appendix A to Subpart C of... - Illustrations: Cylinder Tensile Sample

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Illustrations: Cylinder Tensile Sample A Appendix... Part 178—Illustrations: Cylinder Tensile Sample The following figures illustrate the recommended locations for test specimens taken from welded cylinders: ER08AU02.013 ER08AU02.014 ER08AU02.015...

  6. 49 CFR Appendix A to Subpart C of... - Illustrations: Cylinder Tensile Sample

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Illustrations: Cylinder Tensile Sample A Appendix... Part 178—Illustrations: Cylinder Tensile Sample The following figures illustrate the recommended locations for test specimens taken from welded cylinders: ER08AU02.013 ER08AU02.014 ER08AU02.015...

  7. Effect of Root Moisture Content and Diameter on Root Tensile Properties

    PubMed Central

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  8. Effect of Root Moisture Content and Diameter on Root Tensile Properties.

    PubMed

    Yang, Yuanjun; Chen, Lihua; Li, Ning; Zhang, Qiufen

    2016-01-01

    The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tree species. Betula platyphylla, Quercus mongolica, Pinus tabulaeformis, and Larix gmelinii, the most popular tree species used for slope stabilization in the rocky mountainous areas of northern China, were used in this study. A tensile test was conducted after root samples were grouped by diameter and moisture content. The results showedthat:1) root moisture content had a significant influence on tensile properties; 2) slightly loss of root moisture content could enhance tensile strength, but too much loss of water resulted in weaker capacity for root elongation, and consequently reduced tensile strength; 3) root diameter had a strong positive correlation with tensile resistance; and4) the roots of Betula platyphylla had the best tensile properties when both diameter and moisture content being controlled. These findings improve our understanding of root tensile properties with root size and moisture, and could be useful for slope stabilization using vegetation. PMID:27003872

  9. Experimental and Numerical Studies on Determination of Indirect Tensile Strength of Rocks

    NASA Astrophysics Data System (ADS)

    Erarslan, Nazife; Liang, Zheng Zhao; Williams, David John

    2012-09-01

    Indirect tension tests using Brisbane tuff Brazilian disc specimens under standard Brazilian jaws and various loading arcs were performed. The standard Brazilian indirect tensile tests caused catastrophic, crushing failure of the disc specimens, rather than the expected tensile splitting failure initiated by a central crack. This led to an investigation of the fracturing of Brazilian disc specimens and the existing indirect tensile Brazilian test using steel loading arcs with different angles. The results showed that the ultimate failure load increased with increasing loading arc angles. With no international standard for determining indirect tensile strength of rocks under diametral load, numerical modelling and analytical solutions were undertaken. Numerical simulations using RFPA2D software were conducted with a heterogeneous material model. The results predicted tensile stress in the discs and visually reproduced the progressive fracture process. It was concluded that standard Brazilian jaws cause catastrophic, crushing failure of the disc specimens instead of producing a central splitting crack. The experimental and numerical results showed that 20° and 30° loading arcs result in diametral splitting fractures starting at the disc centre. Moreover, intrinsic material properties (e.g. fracture toughness) may be used to propose the best loading configuration to determine the indirect tensile strength of rocks. Here, by using numerical outcomes and empirical relationships between fracture toughness and tensile strength, the best loading geometry to obtain the most accurate indirect tensile strength of rocks was the 2α = 30° loading arc.

  10. Effects of Effective Dendrite Size on Dynamic Tensile Properties of Ti-Based Amorphous Matrix Composites

    NASA Astrophysics Data System (ADS)

    Jeon, Changwoo; Park, Jaeyeong; Kim, Choongnyun Paul; Kim, Hyoung Seop; Lee, Sunghak

    2016-04-01

    In this study, dynamic tensile properties of dendrite-containing Ti-based amorphous matrix composites were examined, and effects of dendrite size on dynamic deformation were investigated. The composites contained 73 to 76 vol pct of dendrites whose effective sizes were varied from 63 to 103 μm. The dynamic tensile test results indicated that the ultimate tensile strength increased up to 1.25 GPa, whereas the elongation decreased to 1 pct, although the overall strength and elongation trends followed those of the quasi-static tensile test. According to the observation of dynamic tensile deformation behavior, very few deformation bands were observed beneath the fracture surface in the composite containing large dendrites. In the composite containing small dendrites, deformation bands initiated inside small dendrites propagated into adjacent dendrites through the amorphous matrix, and were crossly intersect perpendicularly in widely deformed areas, which beneficially worked for elongation as well as strength.

  11. 7 CFR 29.6040 - Strength (tensile).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Strength (tensile). 29.6040 Section 29.6040 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS TOBACCO INSPECTION Standards Definitions § 29.6040 Strength (tensile). The stress a tobacco...

  12. 7 CFR 29.6040 - Strength (tensile).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strength (tensile). 29.6040 Section 29.6040 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS TOBACCO INSPECTION Standards Definitions § 29.6040 Strength (tensile). The stress a tobacco...

  13. Surfactant effects on soil aggregate tensile strength

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known regarding a soil aggregate's tensile strength response to surfactants that may be applied to alleviate soil water repellency. Two laboratory investigations were performed to determine surfactant effects on the tensile strength of 1) Ap horizons of nine wettable, agricultural soils co...

  14. 7 CFR 29.6040 - Strength (tensile).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Strength (tensile). 29.6040 Section 29.6040 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS TOBACCO INSPECTION Standards Definitions § 29.6040 Strength (tensile). The stress a tobacco...

  15. 7 CFR 29.6040 - Strength (tensile).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Strength (tensile). 29.6040 Section 29.6040 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS TOBACCO INSPECTION Standards Definitions § 29.6040 Strength (tensile). The stress a tobacco...

  16. 7 CFR 29.6040 - Strength (tensile).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Strength (tensile). 29.6040 Section 29.6040 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS TOBACCO INSPECTION Standards Definitions § 29.6040 Strength (tensile). The stress a tobacco...

  17. In vitro tensile strength of luting cements on metallic substrate.

    PubMed

    Orsi, Iara A; Varoli, Fernando K; Pieroni, Carlos H P; Ferreira, Marly C C G; Borie, Eduardo

    2014-01-01

    The aim of this study was to determine the tensile strength of crowns cemented on metallic substrate with four different types of luting agents. Twenty human maxillary molars with similar diameters were selected and prepared to receive metallic core castings (Cu-Al). After cementation and preparation the cores were measured and the area of crown's portion was calculated. The teeth were divided into four groups based on the luting agent used to cement the crowns: zinc phosphate cement; glass ionomer cement; resin cement Rely X; and resin cement Panavia F. The teeth with the crowns cemented were subjected to thermocycling and later to the tensile strength test using universal testing machine with a load cell of 200 kgf and a crosshead speed of 0.5 mm/min. The load required to dislodge the crowns was recorded and converted to MPa/mm(2). Data were subjected to Kruskal-Wallis analysis with a significance level of 1%. Panavia F showed significantly higher retention in core casts (3.067 MPa/mm(2)), when compared with the other cements. Rely X showed a mean retention value of 1.877 MPa/mm(2) and the zinc phosphate cement with 1.155 MPa/mm(2). Glass ionomer cement (0.884 MPa/mm(2)) exhibited the lowest tensile strength value. Crowns cemented with Panavia F on cast metallic posts and cores presented higher tensile strength. The glass ionomer cement showed the lowest tensile strength among all the cements studied. PMID:25140718

  18. Tensile Properties of Contractile and Synthetic Vascular Smooth Muscle Cells

    NASA Astrophysics Data System (ADS)

    Miyazaki, Hiroshi; Hasegawa, Yoshitaka; Hayashi, Kozaburo

    Tensile properties of vascular smooth muscle cells (VSMCs) of synthetic and contractile phenotypes were determined using a newly developed tensile test system. Synthetic and contractile VSMCs were isolated from the rabbit thoracic aorta with an explant and an enzymatic digestion method, respectively. Each cell floated in Hanks' balanced salt solution of 37°C was attached to the fine tips of a pair of micropipettes with a cell adhesive and, then, stretched at the rate of 6µm/sec by moving one of the micropipettes with a linear actuator. Load applied to the cell was measured with a cantilever-type load cell; its elongation was determined from the distance between the micropipette tips using a video dimension analyzer. The synthetic and contractile VSMCs were not broken even at the tensile force of 2.4µN and 3.4µN, respectively. Their stiffness was significantly higher in contractile phenotype (0.17N/m) than in synthetic one (0.09N/m). The different tensile properties between synthetic and contractile cells are attributable to the differences in cytoskeletal structures and contractile apparatus.

  19. Surface, structural and tensile properties of proton beam irradiated zirconium

    NASA Astrophysics Data System (ADS)

    Rafique, Mohsin; Chae, San; Kim, Yong-Soo

    2016-02-01

    This paper reports the surface, structural and tensile properties of proton beam irradiated pure zirconium (99.8%). The Zr samples were irradiated by 3.5 MeV protons using MC-50 cyclotron accelerator at different doses ranging from 1 × 1013 to 1 × 1016 protons/cm2. Both un-irradiated and irradiated samples were characterized using Field Emission Scanning Electron Microscope (FESEM), X-ray Diffraction (XRD) and Universal Testing Machine (UTM). The average surface roughness of the specimens was determined by using Nanotech WSxM 5.0 develop 7.0 software. The FESEM results revealed the formation of bubbles, cracks and black spots on the samples' surface at different doses whereas the XRD results indicated the presence of residual stresses in the irradiated specimens. Williamson-Hall analysis of the diffraction peaks was carried out to investigate changes in crystallite size and lattice strain in the irradiated specimens. The tensile properties such as the yield stress, ultimate tensile stress and percentage elongation exhibited a decreasing trend after irradiation in general, however, an inconsistent behavior was observed in their dependence on proton dose. The changes in tensile properties of Zr were associated with the production of radiation-induced defects including bubbles, cracks, precipitates and simultaneous recovery by the thermal energy generated with the increase of irradiation dose.

  20. Use and Storage of Test and Operations Data from the High Temperature Test Reactor Acquired by the US Government from the Japan Atomic Energy Agency

    SciTech Connect

    Hans Gougar

    2010-02-01

    This document describes the use and storage of data from the High Temperature Test Reactor (HTTR) acquired from the Japan Atomic Energy Agency (JAEA) by the U.S. Government for high temperature reactor research under the Next Generation Nuclear Plant (NGNP) Project.

  1. Validation of the shear punch-tensile correlation technique using irradiated materials

    SciTech Connect

    Hankin, G.L.; Faulkner, R.G.; Toloczko, M.B.; Hamilton, M.L.

    1998-03-01

    It was recently demonstrated that tensile data could be successfully related to shear punch data obtained on transmission electron microscopy (TEM) discs for a variety of irradiated alloys exhibiting yield strengths that ranged from 100 to 800 MPa. This implies that the shear punch test might be a viable alternative for obtaining tensile properties using a TEM disk, which is much smaller than even the smallest miniature tensile specimens, especially when irradiated specimens are not available or when they are too radioactive to handle easily. The majority of the earlier tensile-shear punch correlation work was done using a wide variety of unirradiated materials. The current work extends this correlation effort to irradiated materials and demonstrates that the same relationships that related shear punch tests remain valid for irradiated materials. Shear punch tests were performed on two sets of specimens. In the first group, three simple alloys from the {sup 59}Ni isotopic doping series in the solution annealed and cold worked conditions were irradiated at temperatures ranging from 365 to 495 C in the Fast Flux Test Facility. The corresponding tensile data already existed for tensile specimens fabricated from the same raw materials and irradiated side-by-side with the disks. In the second group, three variants of 316 stainless steel were irradiated in FFTF at 5 temperatures between 400 and 730 C to doses ranging from 12.5 to 88 dpa. The specimens were in the form of both TEM and miniature tensile specimens and were irradiated side-by-side.

  2. Small screw study: Interim report on fastener tensile strength and optimum thread depth

    SciTech Connect

    Diegert, K.V.; Dorrell, L.R.; Reese, R.T.; Lazarus, L.J.; Allied-Signal Aerospace Co., Kansas City, MO . Kansas City Div.)

    1989-10-01

    This report summarizes about 1260 tests performed on small threaded fasteners (equal to or less than 1/4 inch in diameter and designated as 1/4-20 UNC, {number sign}4-40 UNC, {number sign}2-56 UNC, and 1.0 UNM). Tests determined the tensile strengths of the screws, the lengths of engagement needed to develop the full tensile strengths when the screws were engaged in 6061-T6 Aluminum, Hiperco 50, and 303 Stainless Steel, and whether relationships existed between the tensile strengths and Knoop Micro-Hardness measurements taken on the threaded ends of the screws. 17 figs., 13 tabs.

  3. Estimating the tensile strength of super hard brittle materials using truncated spheroidal specimens

    NASA Astrophysics Data System (ADS)

    Serati, Mehdi; Alehossein, Habib; Williams, David J.

    2015-05-01

    New approaches need to be introduced to measure the tensile capacity of super hard materials since the standard methods are not effective. To pursue this objective, a series of laboratory tests were constructed to replicate the fracture mechanism of diamond-based materials. Experiments indicate that under a certain compressive test condition, stresses normal to the axisymmetric line in truncated spheroidal specimens (bullet-shaped specimens) are in tension contributing to the tensile fracture of the material. From experimental and numerical studies, it is concluded that semi-prolate spheroidal specimens can be used to determine precisely the tensile strength of brittle stiff diamond-like composites.

  4. High-temperature tensile properties of fiber reinforced reaction bonded silicon nitride

    NASA Technical Reports Server (NTRS)

    Jablonski, David A.; Bhatt, Ramakrishna T.

    1990-01-01

    Measurements of tensile properties of unidirectional silicon carbide fiber-reinforced reaction-bonded silicon nitride (SiC/RBSN) composite specimens were carried out in air at 25, 1300, and 1500 C, using a new testing technique and a specially designed gripping system that minimizes bending moment and assures that failure always occurred in the gage section. The material was found to display metallike stress-strain behavior at all temperatures tested, and a noncatastrophic failure beyond the matrix fracture. The tensile properties were found to be temperature dependent, with the values of the ultimate tensile strength decreasing with temperature, from 543 MPa at 25 C to 169 at 1500 C.

  5. Effect of strain rate on formability in warm deep drawing of high tensile strength steel sheet

    NASA Astrophysics Data System (ADS)

    Yoshihara, Shoichiro; Iwamatsu, Go

    2014-10-01

    In tensile test of the high tensile strength steel, tensile strength isdrastically decreased as the temperature is raised. Then, the strain rate sensitivity exponent of high tensile strength steel (SUS631) in this study is high at 800 degrees especially. Also, elongation is increased as the temperature is raised. In deep drawing, the maximum punch load of the high tensile strength steel is examined on difference punch speed at 600 and 800 degrees. On the other hand, finite element (FE) simulation was used for the possibility to evaluate the forming load on difference punch speed in warm deep drawing. In FE simulation, we have considered both the strain hardening exponent and the strain rate sensitivity exponent (m-value) because we cannot neglect m-value 0.184 at 800 degrees. The tendency of the forming load in the experiments agrees the results in FE simulation.

  6. The dynamic tensile strength of ice and ice-silicate mixtures

    NASA Technical Reports Server (NTRS)

    Lange, M. A.; Ahrens, T. J.

    1983-01-01

    The dynamic tensile strength of icy media is measured at strain rates on the order of 10,000/sec to aid in the understanding of impact and cratering phenomena. Compressed samples consisting of ice and ice-silicate mixtures with 5 and 30 wt % sand were impacted at temperatures between 230 and 250 K by projectile plexiglas plates imparting the required strain rates in less than 0.75 microsec. Taking the tensile stress corresponding to the transition from intact to spalled or fragmented samples as the dynamic tensile strength, strengths of 17, 20 and 22 MPa were obtained for the pure ice, 5 wt % sand, and 30 wt % sand specimens, respectively. The values lie considerably above those observed in static testing. A continuum fracturing model is used to obtain relations between tensile strength and stress rate as well as to derive stress and damage histories during tensile loading and the size distribution of icy fragments as a function of strain rate.

  7. High temperature, short term tensile strength of C6000/PMR-15 composites

    NASA Technical Reports Server (NTRS)

    Digiovanni, P. R.; Paterson, D.

    1985-01-01

    Tensile tests were conducted on 0 unidirectionally reinforced Celion 6000 graphite fibers in PMR-15 polyimide matrix. Tensile strengths for coupons subjected to short and long term uniform temperatures were obtained. Thick coupons, heated on one side to produce significant transient through thickness temperature gradients, were tested and compared to the strength of specimens with uniform temperature distributions. All coupons were radiantly heated and reached maximum test temperatures within 15 sec. Tensile loads were applied to the coupons after 15 sec of elevated temperature exposure. Loading rates were selected so that specimen failures occurred within a maximum of 45 sec after reaching the test temperature. Results indicate that significant tensile strength remains beyond the material post cure temperature.

  8. Dynamic tensile strength of lunar rock types

    NASA Technical Reports Server (NTRS)

    Cohn, S. N.; Ahrens, T. J.

    1981-01-01

    The dynamic tensile strength of four rocks are determined. A flat plate impact experiment is employed to generate approximately one-microsecond-duration tensile stress pulses in rock samples by superposing rarefaction waves to induce fracture. It is noted that the effect of chemical weathering and other factors has not been explicitly studied. The given tensile strengths are based on a series of experiments on each rock where determination of incipient spallation is made by terminal microscopic examination. The data are generally consistent with previous determinations, at least one of which was for a significantly chemically altered but physically coherent rock.

  9. The Uniaxial Tensile Response of Porous and Microcracked Ceramic Materials

    SciTech Connect

    Pandey, Amit; Shyam, Amit; Watkins, Thomas R; Lara-Curzio, Edgar; Lara-Curzio, Edgar; Stafford, Randall; Hemker, Kevin J

    2014-01-01

    The uniaxial tensile stress-strain behavior of three porous ceramic materials was determined at ambient conditions. Test specimens in the form of thin beams were obtained from the walls of diesel particulate filter honeycombs and tested using a microtesting system. A digital image correlation technique was used to obtain full-field 2D in-plane surface displacement maps during tensile loading, and in turn, the 2D strains obtained from displacement fields were used to determine the Secant modulus, Young s modulus and initial Poisson s ratio of the three porous ceramic materials. Successive unloading-reloading experiments were performed at different levels of stress to decouple the linear elastic, anelastic and inelastic response in these materials. It was found that the stress-strain response of these materials was non-linear and that the degree of nonlinearity is related to the initial microcrack density and evolution of damage in the material.

  10. Examination of a Rock Failure Criterion Based on Circumferential Tensile Strain

    NASA Astrophysics Data System (ADS)

    Fujii, , Y.; Kiyama, , T.; Ishijima, Y.; Kodama, J.

    Uniaxial compression, triaxial compression and Brazialian tests were conducted on several kinds of rock, with particular attention directed to the principal tensile strain. In this paper we aim to clarify the effects of the experimental environment-such as confining pressure, loading rate, water content and anisotropy-on the critical tensile strain, i.e., the measured principal tensile strain at peak load.It was determined that the chain-type extensometer is a most suitable method for measuring the critical tensile strain in uniaxial compression tests. It is also shown that the paper-based strain gage, whose effective length is less than or equal to a tenth of the specimen's diameter and glued on with a rubber-type adhesive, can be effectively used in the Brazilian tests.The effect of confining pressure PC on the critical tensile strain ɛTC in the brittle failure region was between -0.02 × 10-10 Pa-1 and 0.77 × 10-10 Pa-1. This pressure sensitivity is small compared to the critical tensile strain values of around -0.5 × 10-2. The strain rate sensitivities ∂ɛTC/∂{log(d|ɛ|/dt)} were observed in the same way as the strength constants in other failure criteria. They were found to be from -0.10 × 10-3 to -0.52 × 10-3 per order of magnitude in strain rate in the triaxial tests. The average magnitude of the critical tensile strain ɛTC increased due to the presence of water by 4% to 20% for some rocks, and decreased by 22% for sandstone. It can at least be said that the critical tensile strain is less sensitive to water content than the uniaxial compressive strength under the experimental conditions reported here. An obvious anisotropy was observed in the P-wave velocity and in the uniaxial compressive strength of Pombetsu sandstone. It was not observed, however, in the critical tensile strain, although the data do show some variation.A "tensile strain criterion" was proposed, based on the above experimental results. This criterion signifies that stress begins

  11. Elastic-plastic analysis of the SS-3 tensile specimen

    SciTech Connect

    Majumdar, S.

    1998-09-01

    Tensile tests of most irradiated specimens of vanadium alloys are conducted using the miniature SS-3 specimen which is not ASTM approved. Detailed elastic-plastic finite element analysis of the specimen was conducted to show that, as long as the ultimate to yield strength ratio is less than or equal to 1.25 (which is satisfied by many irradiated materials), the stress-plastic strain curve obtained by using such a specimen is representative of the true material behavior.

  12. Tensile and flexural strength of commercially pure titanium submitted to laser and tungsten inert gas welds.

    PubMed

    Atoui, Juliana Abdallah; Felipucci, Daniela Nair Borges; Pagnano, Valéria Oliveira; Orsi, Iara Augusta; Nóbilo, Mauro Antônio de Arruda; Bezzon, Osvaldo Luiz

    2013-01-01

    This study evaluated the tensile and flexural strength of tungsten inert gas (TIG) welds in specimens made of commercially pure titanium (CP Ti) compared with laser welds. Sixty cylindrical specimens (2 mm diameter x 55 mm thick) were randomly assigned to 3 groups for each test (n=10): no welding (control), TIG welding (10 V, 36 A, 8 s) and Nd:YAG laser welding (380 V, 8 ms). The specimens were radiographed and subjected to tensile and flexural strength tests at a crosshead speed of 1.0 mm/min using a load cell of 500 kgf applied on the welded interface or at the middle point of the non-welded specimens. Tensile strength data were analyzed by ANOVA and Tukey's test, and flexural strength data by the Kruskal-Wallis test (α=0.05). Non-welded specimens presented significantly higher tensile strength (control=605.84 ± 19.83) (p=0.015) and flexural strength (control=1908.75) (p=0.000) than TIG- and laser-welded ones. There were no significant differences (p>0.05) between the welding types for neither the tensile strength test (TIG=514.90 ± 37.76; laser=515.85 ± 62.07) nor the flexural strength test (TIG=1559.66; laser=1621.64). As far as tensile and flexural strengths are concerned, TIG was similar to laser and could be suitable to replace laser welding in implant-supported rehabilitations. PMID:24474361

  13. Tensile set behavior of Foley catheter balloons.

    PubMed

    Joseph, R; Ramesh, P; Sivakumar, R

    1999-01-01

    The removal of indwelling urinary balloon catheters from patients is usually associated with many problems. The problems such as balloon deflation failure; encrustations on balloons, eyes, and lumen; and catheter associated infections are widely discussed in the literature. The tensile set exhibited by the catheter balloon material could also play a role and further complicate the removal process. This article addresses this issue by comparing the tensile set behavior of the balloon material from three commercially available Foley catheters. The balloon materials were subjected to aging in synthetic urine at 37 degrees C for 28 days to simulate clinical conditions. The deflation time of catheter balloons aged in similar conditions were also measured. It was found that different brands of catheters exhibited statistically significant differences in their properties. The tensile set data of the aged samples could be correlated with the deflation time of the balloons. The clinical significance of the tensile set is also highlighted. PMID:10029146

  14. Strain rate effects on tensile strength of iron green bodies

    NASA Astrophysics Data System (ADS)

    Nishida, Masahiro; Kuroyanagi, Yuki; Häggblad, Hans-Åke; Jonsén, Pär; Gustafsson, Gustaf

    2015-09-01

    Impact tensile strength of iron green bodies with densities of 7.2 and 7.4 g/cm3 was examined by Brazilian test using the split-Hopkinson pressure bar (Kolsky bar) method. The powder material used for the experiments was a press-ready premix containing Distaloy AE, graphite, and lubricant. During dynamic compression, the failure behavior of specimens was observed using a high-speed video camera. The failure stress and failure behavior of dynamic compressive tests were compared with those of static compressive tests.

  15. Effect of Strain-Induced Martensite on Tensile Properties and Hydrogen Embrittlement of 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Kim, Young Suk; Bak, Sang Hwan; Kim, Sung Soo

    2016-01-01

    Room temperature tensile tests have been conducted at different strain rates ranging from 2 × 10-6 to 1 × 10-2/s on hydrogen-free and hydrogen-charged 304 stainless steel (SS). Using a ferritescope and neutron diffraction, the amount of strain-induced martensite (SIM) has been in situ measured at the center region of the gage section of the tensile specimens or ex situ measured on the fractured tensile specimens. The ductility, tensile stress, hardness, and the amount of SIM increase with decreasing strain rate in hydrogen-free 304 SS and decrease in hydrogen-charged one. Specifically, SIM that forms during tensile tests is beneficial in increasing the ductility, strain hardening, and tensile stress of 304 SS, irrespective of the presence of hydrogen. A correlation of the tensile properties of hydrogen-free and hydrogen-charged 304 SS and the amount of SIM shows that hydrogen suppresses the formation of SIM in hydrogen-charged 304 SS, leading to a ductility loss and localized brittle fracture. Consequently, we demonstrate that hydrogen embrittlement of 304 SS is related to hydrogen-suppressed formation of SIM, corresponding to the disordered phase, according to our proposition. Compelling evidence is provided by the observations of the increased lattice expansion of martensite with decreasing strain rate in hydrogen-free 304 SS and its lattice contraction in hydrogen-charged one.

  16. Tensile Hoop Behavior of Irradiated Zircaloy-4 Nuclear Fuel Cladding

    SciTech Connect

    Jaramillo, Roger A; Hendrich, WILLIAM R; Packan, Nicolas H

    2007-03-01

    A method for evaluating the room temperature ductility behavior of irradiated Zircaloy-4 nuclear fuel cladding has been developed and applied to evaluate tensile hoop strength of material irradiated to different levels. The test utilizes a polyurethane plug fitted within a tubular cladding specimen. A cylindrical punch is used to compress the plug axially, which generates a radial displacement that acts upon the inner diameter of the specimen. Position sensors track the radial displacement of the specimen outer diameter as the compression proceeds. These measurements coupled with ram force data provide a load-displacement characterization of the cladding response to internal pressurization. The development of this simple, cost-effective, highly reproducible test for evaluating tensile hoop strain as a function of internal pressure for irradiated specimens represents a significant advance in the mechanical characterization of irradiated cladding. In this project, nuclear fuel rod assemblies using Zircaloy-4 cladding and two types of mixed uranium-plutonium oxide (MOX) fuel pellets were irradiated to varying levels of burnup. Fuel pellets were manufactured with and without thermally induced gallium removal (TIGR) processing. Fuel pellets manufactured by both methods were contained in fuel rod assemblies and irradiated to burnup levels of 9, 21, 30, 40, and 50 GWd/MT. These levels of fuel burnup correspond to fast (E > 1 MeV) fluences of 0.27, 0.68, 0.98, 1.4 and 1.7 1021 neutrons/cm2, respectively. Following irradiation, fuel rod assemblies were disassembled; fuel pellets were removed from the cladding; and the inner diameter of cladding was cleaned to remove residue materials. Tensile hoop strength of this cladding material was tested using the newly developed method. Unirradiated Zircaloy-4 cladding was also tested. With the goal of determining the effect of the two fuel types and different neutron fluences on clad ductility, tensile hoop strength tests were

  17. A theoretical model to predict tensile deformation behavior of balloon catheter.

    PubMed

    Todo, Mitsugu; Yoshiya, Keiji; Matsumoto, Takuya

    2016-09-01

    In this technical note, a simple theoretical model was proposed to express the tensile deformation and fracture of balloon catheter tested by the ISO standard using piece-wise linear force-displacement relations. The model was then validated by comparing with the tensile force-displacement behaviors of two types of typical balloon catheters clinically used worldwide. It was shown that the proposed model can effectively be used to express the tensile deformation behavior and easily be handled by physicians who are not familiar with mechanics of materials. PMID:27214691

  18. Tensile Modulus Measurements of Carbon Nanotube Incorporated Electrospun Polymer Fibers

    NASA Astrophysics Data System (ADS)

    Ozturk, Yavuz; Kim, Jaemin; Shin, Kwanwoo

    2006-03-01

    Electrospinning has become a popular method for producing continuous polymer fibers with diameters in sub-micron scale. By this technique uniaxially aligned fibers can also be obtained, by using two separate parallel strips as conductive collectors. Uniaxial alignment of polymer fibers gives us the chance to well-characterize their structural properties via tensile modulus measurements. Here we report a simple and new technique for tensile testing of polymer fibers which employs a computerized spring-balance/step-motor setup. The key point in our technique is the production of fibers directly on the tensile tester by using two vertical strips as collectors. By this way, even fibers of very brittle nature can be tested without handling them. Calculation of total cross-sectional areas - which is crucial for determining stress values - was done by using scanning electron and optical microscope images for each sample. In this study we have investigated mechanical properties of Polystyrene (PS), Polymethylmethacrylate (PMMA) and PS/PMMA blend fibers; as well as Carbon Nanotube (CNT) incorporated PS, PMMA and PS/PMMA blend fibers. It is expected that the extraordinary mechanical properties of CNTs can be transferred into polymer matrix, by their incorporation into confined space within electrospun fibers. Here we analyzed the influence of CNT on polymer fibers as function of CNT amounts.

  19. Hoop Tensile Properties of Ceramic Matrix Composite Cylinders

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; DiCarlo, James A.; Yun, HeeMan; Barnett, Terry

    2004-01-01

    Tensile stress-strain properties in the hoop direction were obtained for 100-mm diameter SiC/SiC ceramic matrix composite cylinders using ring specimens machined form the cylinder ends. The cylinders were fabricated from 2D balanced SiC fabric with several material variants, including wall thickness (6,8, and 12 plies), SiC fiber type (Sylramic, Sylramic-iBN, Hi-Nicalon, and Hi-Nicalon S), fiber sizing type, and matrix type (full CVI SiC, and partial CVI SiC plus slurry cast + melt-infiltrated SiC-Si). Fiber ply splices existed in all the hoops. Tensile hoop measurements are made at room temperature and 1200 C using hydrostatic ring test facilities. The failure mode of the hoops, determined through microstructural examination, is presented. The hoop properties are compared with in-plane data measured on flat panels using same material variants, but containing no splices.

  20. Tensile deformation mechanisms of ABS/PMMA/EMA blends

    NASA Astrophysics Data System (ADS)

    Wang, S. H.; Gao, J.; Lin, S. X.; Zhang, P.; Huang, J.; Xu, L. L.

    2014-08-01

    The tensile deformation mechanisms of acrylonitrile - butadiene - styrene (ABS) / polymethyl methacrylate (PMMA) blends toughened by ethylene methacrylate (EMA) copolymer was investigated by analysing the fracture morphology. ABS/PMMA was blended with EMA copolymer by melt mixing technique using co-rotating twin extruder. Tensile tests show that the elongation at break of ABS/PMMA blends can be efficiently improved with the increase in EMA content. Fracture morphology of ABS/PMMA/EMA blends reveals that the material yield induced by hollowing-out of EMA particles and its propagation into yield zone is the main toughening mechanism. Moreover, the appearance that EMA particles in the central area are given priority to hollowing-out may be related to the skin-core structure of the injection moulded parts caused by the different cooling rate between surface and inside in the process of injection moulding.

  1. On the tensile strength distribution of multiwalled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Barber, Asa H.; Andrews, Rodney; Schadler, Linda S.; Wagner, H. Daniel

    2005-11-01

    Individual multiwalled carbon nanotubes grown by chemical vapor deposition (CVD) were tensile tested within the chamber of an electron microscope using an atomic force microscope-based technique. Weibull-Poisson statistics could accurately model the nanotube tensile strength data. Weibull shape and scale parameters of 1.7 and 109GPa were obtained. The former reflects a wide variability in strength similar to that observed for high-modulus graphite fibers, while the latter indicates that the irregular CVD-grown tube wall structure requires, in some cases, higher breaking forces than more regular tube wall structures. This apparent strengthening mechanism is most likely caused by an enhanced interaction between the walls of the nanotube.

  2. Making High-Tensile-Strength Amalgam Components

    NASA Technical Reports Server (NTRS)

    Grugel, Richard

    2008-01-01

    Structural components made of amalgams can be made to have tensile strengths much greater than previously known to be possible. Amalgams, perhaps best known for their use in dental fillings, have several useful attributes, including room-temperature fabrication, corrosion resistance, dimensional stability, and high compressive strength. However, the range of applications of amalgams has been limited by their very small tensile strengths. Now, it has been discovered that the tensile strength of an amalgam depends critically on the sizes and shapes of the particles from which it is made and, consequently, the tensile strength can be greatly increased through suitable choice of the particles. Heretofore, the powder particles used to make amalgams have been, variously, in the form of micron-sized spheroids or flakes. The tensile reinforcement contributed by the spheroids and flakes is minimal because fracture paths simply go around these particles. However, if spheroids or flakes are replaced by strands having greater lengths, then tensile reinforcement can be increased significantly. The feasibility of this concept was shown in an experiment in which electrical copper wires, serving as demonstration substitutes for copper powder particles, were triturated with gallium by use of a mortar and pestle and the resulting amalgam was compressed into a mold. The tensile strength of the amalgam specimen was then measured and found to be greater than 10(exp 4) psi (greater than about 69 MPa). Much remains to be done to optimize the properties of amalgams for various applications through suitable choice of starting constituents and modification of the trituration and molding processes. The choice of wire size and composition are expected to be especially important. Perusal of phase diagrams of metal mixtures could give insight that would enable choices of solid and liquid metal constituents. Finally, whereas heretofore, only binary alloys have been considered for amalgams

  3. Impact tensile properties and strength development mechanism of glass for reinforcement fiber

    NASA Astrophysics Data System (ADS)

    Kim, T.; Oshima, K.; Kawada, H.

    2013-07-01

    In this study, impact tensile properties of E-glass were investigated by fiber bundle testing under a high strain rate. The impact tests were performed employing two types of experiments. One is the tension-type split Hopkinson pressure bar system, and the other is the universal high-speed tensile-testing machine. As the results, it was found that not only the tensile strength but also the fracture strain of E-glass fiber improved with the strain rate. The absorbed strain energy of this material significantly increased. It was also found that the degree of the strain rate dependency of E-glass fibers on the tensile strength was varied according to fiber diameter. As for the strain rate dependency of the glass fiber under tensile loading condition, change of the small crack-propagation behaviour was considered to clarify the development of the fiber strength. The tensile fiber strength was estimated by employing the numerical simulation based on the slow crack-growth model (SCG). Through the parametric study against the coefficient of the crack propagation rate, the numerical estimation value was obtained for the various testing conditions. It was concluded that the slow crack-growth behaviour in the glass fiber was an essential for the increase in the strength of this material.

  4. Tensile and creep properties of reduced activation ferritic-martensitic steel for fusion energy application

    NASA Astrophysics Data System (ADS)

    Mathew, M. D.; Vanaja, J.; Laha, K.; Varaprasad Reddy, G.; Chandravathi, K. S.; Bhanu Sankara Rao, K.

    2011-10-01

    Tensile and creep properties of a reduced activation ferritic-martensitic (RAFM) steel for Indian Test Blanket Module (TBM) to be tested in ITER have been evaluated. The tensile strength was found to decrease with temperature; the rate of decrease being slower in the intermediate temperature range of 450-650 K. Tensile ductility of the steel decreased with increase in temperature up to 650 K, followed by a rapid increase beyond 650 K. Creep studies have been carried out at 773, 823 and 873 K over a stress range of 100-300 MPa. The variation of minimum creep rate with applied stress followed a power law, ɛ = Aσ n. The ' n' value decreased with increase in temperature. The creep rupture life was found to relate inversely with minimum creep rate through the Monkman-Grant relation, t r · ɛ = constant. The tensile and creep properties of the steel were comparable with those of Eurofer 97.

  5. The development of a tensile-shear punch correlation for yield properties of model austenitic alloys

    SciTech Connect

    Hankin, G.L.; Faulkner, R.G.; Hamilton, M.L.; Garner, F.A.

    1997-08-01

    The effective shear yield and maximum strengths of a set of neutron-irradiated, isotopically tailored austentic alloys were evaluated using the shear punch test. The dependence on composition and neutron dose showed the same trends as were observed in the corresponding miniature tensile specimen study conducted earlier. A single tensile-shear punch correlation was developed for the three alloys in which the maximum shear stress or Tresca criterion was successfully applied to predict the slope. The correlation will predict the tensile yield strength of the three different austenitic alloys tested to within {+-}53 MPa. The accuracy of the correlation improves with increasing material strength, to within {+-} MPa for predicting tensile yield strengths in the range of 400-800 MPa.

  6. Controlled Chemistry Helium High Temperature Materials Test Loop

    SciTech Connect

    Richard N. WRight

    2005-08-01

    A system to test aging and environmental effects in flowing helium with impurity content representative of the Next Generation Nuclear Plant (NGNP) has been designed and assembled. The system will be used to expose microstructure analysis coupons and mechanical test specimens for up to 5,000 hours in helium containing potentially oxidizing or carburizing impurities controlled to parts per million levels. Impurity levels in the flowing helium are controlled through a feedback mechanism based on gas chromatography measurements of the gas chemistry at the inlet and exit from a high temperature retort containing the test materials. Initial testing will focus on determining the nature and extent of combined aging and environmental effects on microstructure and elevated temperature mechanical properties of alloys proposed for structural applications in the NGNP, including Inconel 617 and Haynes 230.

  7. Correlation between shear punch and tensile data for neutron-irradiated aluminum alloys

    SciTech Connect

    Hamilton, M.L.; Edwards, D.J.; Toloczko, M.B.

    1995-04-01

    This work was performed to determine whether shear punch and tensile data obtained on neutron irradiated aluminum alloys exhibited the same type of relationship as had been seen in other work and to assess the validity of extrapolating the results to proton-irradiated alloys. This work was also meant to be the first of a series of similar test matrices designed to determine whether the shear punch/tensile relationship varied or was the same for different alloy classes.

  8. An investigation into geometry and microstructural effects upon the ultimate tensile strengths of butt welds

    NASA Technical Reports Server (NTRS)

    Gordon, Stephen S.

    1992-01-01

    A mathematical theory was evaluated empirically. This theory predicts weld ultimate tensile strength based on material properties and fusion line angles, mismatch, peaking, and weld widths. Welds were made on 1/4 and 1/2 in. aluminum 2219-T87, their geometries were measured, they were tensile tested, and these results were compared to theoretical predictions. Statistical analysis of results was performed to evaluate correlation of theory to results for many different categories of weld geometries.

  9. Tensile and fatigue behavior of tungsten/copper composites

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Gabb, Timothy P.; Kim, Y. S.

    1989-01-01

    Work on W/Cu unidirectional composites was initiated to study the behavior of this ductile-ductile composite system under thermomechanical fatigue and to examine the applicability of fatigue-life prediction methods for thermomechanical fatigue of this metal matrix composite. The first step was to characterize the tensile behavior of four ply, 10 vol. percent W/Cu plates at room and elevated temperatures. Fatigue tests were conducted in load control on 0 degree specimens at 260 C. The maximum cyclic stress was varied but the minimum cyclic stress was kept constant. All tests were performed in vacuum. The strain at failure increased with increasing maximum cyclic stress.

  10. The effect of grain size on dynamic tensile extrusion behaviour

    NASA Astrophysics Data System (ADS)

    Park, Leeju; Kim, Hack Jun; Kim, Seok Bong

    2015-09-01

    Dynamic tensile extrusion (DTE) tests were conducted on coarse grained and ultrafine grained (UFG) OFHC Cu, Interstitial free (IF) Steel, and pure Ta. Equal channel angular pressing (ECAP) of 16passes with Bc for Cu, IF Steel and 4 passes for Ta was employed to fabricated UFG materials. DTE tests were carried out by launching the sphere samples (Dia. 7.62 mm) to the conical extrusion die at a speed of ˜500 m/sec. The fragmentation behavior of the soft-recovered fragments were examined and compared with each other. The DTE fragmentation behavior of CG and UFG was numerically simulated by the LS-DYNA FEM code.

  11. Dynamic tensile failure mechanics of the musculoskeletal neck using a cadaver model.

    PubMed

    Yliniemi, Eno M; Pellettiere, Joseph A; Doczy, Erica J; Nuckley, David J; Perry, Chris E; Ching, Randal P

    2009-05-01

    Although the catapult phase of pilot ejections has been well characterized in terms of human response to compressive forces, the effect of the forces on the human body during the ensuing ejection phases (including windblast and parachute opening shock) has not been thoroughly investigated. Both windblast and parachute opening shock have been shown to induce dynamic tensile forces in the human cervical spine. However, the human tolerance to such loading is not well known. Therefore, the main objective of this research project was to measure human tensile neck failure mechanics to provide data for computational modeling, anthropometric test device development, and improved tensile injury criteria. Twelve human cadaver specimens, including four females and eight males with a mean age of 50.1+/-9 years, were subjected to dynamic tensile loading through the musculoskeletal neck until failure occurred. Failure load, failure strain, and tensile stiffness were measured and correlated with injury type and location. The mean failure load for the 12 specimens was 3100+/-645 N, mean failure strain was 16.7+/-5.4%, and mean tensile stiffness was 172+/-54.5 N/mm. The majority of injuries (8) occurred in the upper cervical spine (Oc-C3), and none took place in the midcervical region (C3-C5). The results of this study assist in filling the existing void in dynamic tensile injury data and will aid in developing improved neck injury prevention strategies. PMID:19388771

  12. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    NASA Astrophysics Data System (ADS)

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  13. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials.

    PubMed

    Wang, Shupeng; Zhang, Zhihui; Ren, Luquan; Zhao, Hongwei; Liang, Yunhong; Zhu, Bing

    2014-06-01

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument. PMID:24985848

  14. A novel in situ device based on a bionic piezoelectric actuator to study tensile and fatigue properties of bulk materials

    SciTech Connect

    Wang, Shupeng; Zhang, Zhihui Ren, Luquan; Liang, Yunhong; Zhao, Hongwei; Zhu, Bing

    2014-06-15

    In this work, a miniaturized device based on a bionic piezoelectric actuator was developed to investigate the static tensile and dynamic fatigue properties of bulk materials. The device mainly consists of a bionic stepping piezoelectric actuator based on wedge block clamping, a pair of grippers, and a set of precise signal test system. Tensile and fatigue examinations share a set of driving system and a set of signal test system. In situ tensile and fatigue examinations under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. The structure and working principle of the device were discussed and the effects of output difference between two piezoelectric stacks on the device were theoretically analyzed. The tensile and fatigue examinations on ordinary copper were carried out using this device and its feasibility was verified through the comparison tests with a commercial tensile examination instrument.

  15. Effects of Long-Term Thermal Exposure on Commercially Pure Titanium Grade 2 Elevated-Temperature Tensile Properties

    NASA Technical Reports Server (NTRS)

    Ellis, David L.

    2012-01-01

    Elevated-temperature tensile testing of commercially pure titanium (CP Ti) Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K (531 and 711 F) for times up to 5000 h. The tensile testing revealed some statistical differences between the 11 thermal treatments, but most thermal treatments were statistically equivalent. Previous data from room temperature tensile testing was combined with the new data to allow regression and development of mathematical models relating tensile properties to temperature and thermal exposure. The results indicate that thermal exposure temperature has a very small effect, whereas the thermal exposure duration has no statistically significant effects on the tensile properties. These results indicate that CP Ti Grade 2 will be thermally stable and suitable for long-duration space missions.

  16. Experimental and numerical study on tensile strength of concrete under different strain rates.

    PubMed

    Min, Fanlu; Yao, Zhanhu; Jiang, Teng

    2014-01-01

    The dynamic characterization of concrete is fundamental to understand the material behavior in case of heavy earthquakes and dynamic events. The implementation of material constitutive law is of capital importance for the numerical simulation of the dynamic processes as those caused by earthquakes. Splitting tensile concrete specimens were tested at strain rates of 10(-7) s(-1) to 10(-4) s(-1) in an MTS material test machine. Results of tensile strength versus strain rate are presented and compared with compressive strength and existing models at similar strain rates. Dynamic increase factor versus strain rate curves for tensile strength were also evaluated and discussed. The same tensile data are compared with strength data using a thermodynamic model. Results of the tests show a significant strain rate sensitive behavior, exhibiting dynamic tensile strength increasing with strain rate. In the quasistatic strain rate regime, the existing models often underestimate the experimental results. The thermodynamic theory for the splitting tensile strength of concrete satisfactorily describes the experimental findings of strength as effect of strain rates. PMID:24883355

  17. Comparative evaluation of tensile strength of Gutta-percha cones with a herbal disinfectant

    PubMed Central

    Mahali, Raghunandhan Raju; Dola, Binoy; Tanikonda, Rambabu; Peddireddi, Suresh

    2015-01-01

    Aim: To evaluate and compare the tensile strength values and influence of taper on the tensile strength of Gutta-percha (GP) cones after disinfection with sodium hypochlorite (SH) and Aloe vera gel (AV). Materials and Methods: Sixty GP cones of size 110, 2% taper, 60 GP cones F3 ProTaper, and 60 GP of size 30, 6% taper were obtained from sealed packs as three different groups. Experimental groups were disinfected with 5.25% SH and 90% AV gel except the control group. Tensile strengths of GP were measured using the universal testing machine. Results: The mean tensile strength values for Group IA, IIA and IIIA are 11.8 MPa, 8.69 MPa, and 9.24 MPa, respectively. Results were subjected to statistical analysis one-way analysis of variance test and Tukey post-hoc test. 5.25% SH solutions decreased the tensile strength of GP cones whereas with 90% AV gel it was not significantly altered. Conclusion: Ninety percent Aloe vera gel as a disinfectant does not alter the tensile strength of GP cones PMID:26752842

  18. Experimental and Numerical Study on Tensile Strength of Concrete under Different Strain Rates

    PubMed Central

    Min, Fanlu; Yao, Zhanhu; Jiang, Teng

    2014-01-01

    The dynamic characterization of concrete is fundamental to understand the material behavior in case of heavy earthquakes and dynamic events. The implementation of material constitutive law is of capital importance for the numerical simulation of the dynamic processes as those caused by earthquakes. Splitting tensile concrete specimens were tested at strain rates of 10−7 s−1 to 10−4 s−1 in an MTS material test machine. Results of tensile strength versus strain rate are presented and compared with compressive strength and existing models at similar strain rates. Dynamic increase factor versus strain rate curves for tensile strength were also evaluated and discussed. The same tensile data are compared with strength data using a thermodynamic model. Results of the tests show a significant strain rate sensitive behavior, exhibiting dynamic tensile strength increasing with strain rate. In the quasistatic strain rate regime, the existing models often underestimate the experimental results. The thermodynamic theory for the splitting tensile strength of concrete satisfactorily describes the experimental findings of strength as effect of strain rates. PMID:24883355

  19. Tensile properties of modified 9 Cr-1 Mo steel

    SciTech Connect

    Sikka, V.K.; McDonald, R.E.; Booker, M.K.; Bodine, G.C.

    1982-02-01

    Tensile properties of commercial heats of modified 9 Cr-1 Mo alloy are presented for test temperatures in the range from room temperature to 760/sup 0/C. Data included the effects of melting practice, compositional differences, strain rate (8.0 to 0.00008/min), postweld heat treatment (1 through 112 h at 732/sup 0/C), tempering temperature (732 and 746/sup 0/C versus 760/sup 0/C), isothermal annealing (1038/sup 0/C for 1 h and 704/sup 0/C for 24 h followed by AC), and thermal aging (5000 and 11,600 h at 538, 593, and 649/sup 0/C). The average-to-minimum property range for the yield and ultimate tensile strengths was compared with the similar data range for standard 9 Cr-1 Mo alloy. Tensile data on commercial heats were used to set the room-temperature specified minimum values for the alloy. The conservativeness of the specified minimum values was checked against the data at several strain rates, data after postweld heat treatment at 732/sup 0/C up to 112 h, and data on thermally aged material.

  20. Tensile and impact properties of iron-aluminum alloys

    SciTech Connect

    Alexander, D.J.; Sikka, V.K.

    1993-12-31

    Tensile and impact tests have been conducted on specimens from a series of five heats of iron-aluminum alloys. These results have been compared to data for the iron aluminide alloy FA-129. The transition temperatures of all of the Fe{sub 3}Al-based alloys were similar, but the simple ternary alloy had a much higher upper-shelf energy. The reduced aluminum alloys [based on Fe-8Al (wt %)] had lower transition temperatures and higher upper-shelf energy levels than the Fe{sub 3}Al-type alloys. The reduced aluminum alloy with yttrium showed excellent tensile properties, with a room temperature total elongation of 40%, and a very high upper-shelf energy level. Despite the high tensile ductility at room temperature, the transition temperature of the yttrium-containing alloy was still about 150 C, compared to approximately 300 C for FA-129. In general, the microstructures were coarse and anisotropic. The fracture processes were dominated by second-phase particles.

  1. Microstructure and tensile properties of tungsten at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Shen, Tielong; Dai, Yong; Lee, Yongjoong

    2016-01-01

    In order to support the development of the 5 MW spallation target for the European Spallation Source, the effect of fabrication process on microstructure, ductile-to-brittle transition temperature (DBTT), tensile and fracture behaviour of powder-metallurgy pure tungsten materials has been investigated. A hot-rolled (HR) tungsten piece of 12 mm thickness and a hot-forged (HF) piece of about 80 mm thickness were used to simulate the thin and thick blocks in the target. The two tungsten pieces were characterized with metallography analysis, hardness measurement and tensile testing. The HR piece exhibits an anisotropic grain structure with an average size of about 330 × 140 × 40 μm in rolling, long transverse and short transverse (thickness) directions. The HF piece possesses a bimodal grain structure with about 310 × 170 × 70 μm grain size in deformed part and about 25 μm sized grains remained from sintering process. Hardness (HV0.2) of the HR piece is slightly greater than that of the HF one. The ductility of the HR tungsten specimens is greater than that of the HF tungsten. For the HF tungsten piece, specimens with small grains in gauge section manifest lower ductility but higher strength. The DBTT evaluated from the tensile results is 250-300 °C for the HR tungsten and about 350 °C for the HF tungsten.

  2. Tensile behavior of irradiated SiC fibers

    NASA Astrophysics Data System (ADS)

    Osborne, M. C.; Snead, L. L.; Steiner, D.

    1995-03-01

    The strength and toughness of continuous fiber reinforced ceramic composites (CFCCs) are highly dependent on the fiber strength distribution. To first order, weaker fibers lead to low strength but higher toughness while stronger fibers lead to high strength composites of relatively low toughness. Toughness is associated with pullout of the fibers from the ceramic matrix. It has been shown previously that both strength and toughness of SiC/Nicalon TM composites are drastically changed following irradiation. Tensile results are presented for low oxygen Nicalon fibers neutron irradiated at damage levels of 0.013 displacements per atom (dpa), 0.13 dpa and 0.32 dpa. Single fibers were tensile tested and analyzed, using Weibull statistics, for mean strength and distribution. Tensile modulus was also determined. Using a diffractometer, the fiber grain size and percent crystallinity were determined. The initial results of these low fluence neutron irradiations exhibit no substantial degradation of the properties investigated. Therefore, continued research at higher doses is recommended.

  3. Tensile properties of the inferior glenohumeral ligament.

    PubMed

    Bigliani, L U; Pollock, R G; Soslowsky, L J; Flatow, E L; Pawluk, R J; Mow, V C

    1992-03-01

    The tensile properties of the inferior glenohumeral ligament have been determined in 16 freshly frozen cadaver shoulders. The inferior glenohumeral ligament was divided into three anatomical regions: a superior band, an anterior axillary pouch, and a posterior axillary pouch. This yielded 48 bone-ligament-bone specimens, which were tested to failure in uniaxial tension. The superior band was consistently the thickest region, averaging 2.79 mm. The thickness of the inferior glenohumeral ligament decreased from antero-superiorly to postero-inferiorly. The resting length of all three anatomical regions was not statistically different. Total specimen strain to failure for all bone-ligament-bone specimens averaged 27%. Variations occurred between the three regions, with the anterior pouch specimens failing at a higher strain (34%) than those from the superior band (24%) or the posterior pouch (23%). Strain to failure for the ligament midsubstance (11%) was found to be significantly less than that for the entire specimen (27%). Thus, larger strain must occur near the insertion sites of the inferior glenohumeral ligament. Stress at failure was found to be nearly identical for the three regions of the ligament, averaging 5.5 MPa. These values are lower than those reported for other soft tissues, such as the anterior cruciate ligament and patellar tendon. The anterior pouch was found to be less stiff than the other two regions, perhaps suggesting that it is composed of more highly crimped collagen fibers. Three failure sites were seen for the inferior glenohumeral ligament: the glenoid insertion (40%), the ligament substance (35%), and the humeral insertion (25%). In addition, significant capsular stretching occurred before failure, regardless of the failure mode. PMID:1740736

  4. Comparison of Elevated Temperature Tensile Properties and Fatigue Behavior of Two Variants of a Woven SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Brewer, David N.; Sreeramesh, Kalluri

    2005-01-01

    Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength, and strain at failure) of two variants of a woven SiC/SiC composite, manufactured during two separate time periods (9/99 and 1/01), were determined at 1038 and 1204 C by conducting tensile tests on specimens machined from plates. Continuous cycling fatigue tests (R = 0.05) and 20 cpm) were also conducted at the same two temperatures on specimens from both composites. In this study, average tensile properties, 95% confidence intervals associated with the tensile properties, and geometric mean fatigue lives of both composite materials are compared. The observed similarities and differences in the tensile properties are highlighted and an attempt is made to understand the relationship, if any, between the tensile properties and the fatigue behaviors of the two woven composites.

  5. Dynamic compressive and tensile strengths of spark plasma sintered alumina

    NASA Astrophysics Data System (ADS)

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M. P.; Frage, N.

    2014-06-01

    Fully dense submicron grain size alumina samples were manufactured from alumina nano-powder using Spark Plasma Sintering and tested in two kinds of VISAR-instrumented planar impact tests. In the first kind, samples were loaded by 1-mm tungsten impactors, accelerated to a velocity of about 1 km/s. These tests were aimed at studying the Hugoniot elastic limit (HEL) of Spark Plasma Sintering (SPS)-processed alumina and the decay, with propagation distance, of the elastic precursor wave. In the tests of the second kind, alumina samples of 3-mm thickness were loaded by 1-mm copper impactors accelerated to 100-1000 m/s. These tests were aimed at studying the dynamic tensile (spall) strength of the alumina specimens. The tensile fracture of the un-alloyed alumina shows a monotonic decline of the spall strength with the amplitude of the loading stress pulse. Analysis of the decay of the elastic precursor wave allowed determining the rate of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of the shock-induced inelastic deformation and to clarify the mechanisms responsible for the deformation. The 1-% addition of Cr2O3 decreases the HEL of the SPS-processed alumina by 5-% and its spall strength by 50% but barely affects its static properties.

  6. Dynamic compressive and tensile strengths of spark plasma sintered alumina

    SciTech Connect

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M. P.; Frage, N.

    2014-06-28

    Fully dense submicron grain size alumina samples were manufactured from alumina nano-powder using Spark Plasma Sintering and tested in two kinds of VISAR-instrumented planar impact tests. In the first kind, samples were loaded by 1-mm tungsten impactors, accelerated to a velocity of about 1 km/s. These tests were aimed at studying the Hugoniot elastic limit (HEL) of Spark Plasma Sintering (SPS)-processed alumina and the decay, with propagation distance, of the elastic precursor wave. In the tests of the second kind, alumina samples of 3-mm thickness were loaded by 1-mm copper impactors accelerated to 100–1000 m/s. These tests were aimed at studying the dynamic tensile (spall) strength of the alumina specimens. The tensile fracture of the un-alloyed alumina shows a monotonic decline of the spall strength with the amplitude of the loading stress pulse. Analysis of the decay of the elastic precursor wave allowed determining the rate of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of the shock-induced inelastic deformation and to clarify the mechanisms responsible for the deformation. The 1-% addition of Cr{sub 2}O{sub 3} decreases the HEL of the SPS-processed alumina by 5-% and its spall strength by 50% but barely affects its static properties.

  7. The effect of structure on tensile properties of directionally solidified Zn-based alloys

    NASA Astrophysics Data System (ADS)

    Ares, A. E.; Schvezov, C. E.

    2011-03-01

    The main objective of this study was to measure thermal (cooling rates, temperature gradients and velocities of the liquidus and solidus isotherms), structural (grain size and primary and secondary dendritic arm spacings) and tensile parameters (maximum tensile strength (MTS), yield strength (YS) and ultimate tensile strength (UTS)) in zinc-aluminum (ZA) hypoeutectic (Zn-3 wt%Al) and hypereutectic (Zn-10 wt%Al, Zn-15 wt%Al, Zn-20 wt%Al, Zn-30 wt%Al, Zn-37 wt%Al and Zn-50 wt%Al) alloys directionally solidified, which present columnar, equiaxed and columnar-to-equiaxed transition (CET) structures. The different types of structures were analyzed with optical and Scanning Electron Microscopy (SEM). Correlations between temperature gradient, cooling rate, local solidification time, grain size and dendritic spacings and tensile tests parameters are presented and discussed. The results show the influence of concentration, microstructural arrangement and thermal conditions on the mechanical properties during the solidification process.

  8. Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1975-01-01

    Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

  9. Optimization and Prediction of Ultimate Tensile Strength in Metal Active Gas Welding.

    PubMed

    Ampaiboon, Anusit; Lasunon, On-Uma; Bubphachot, Bopit

    2015-01-01

    We investigated the effect of welding parameters on ultimate tensile strength of structural steel, ST37-2, welded by Metal Active Gas welding. A fractional factorial design was used for determining the significance of six parameters: wire feed rate, welding voltage, welding speed, travel angle, tip-to-work distance, and shielded gas flow rate. A regression model to predict ultimate tensile strength was developed. Finally, we verified optimization of the process parameters experimentally. We achieved an optimum tensile strength (558 MPa) and wire feed rate, 19 m/min, had the greatest effect, followed by tip-to-work distance, 7 mm, welding speed, 200 mm/min, welding voltage, 30 V, and travel angle, 60°. Shield gas flow rate, 10 L/min, was slightly better but had little effect in the 10-20 L/min range. Tests showed that our regression model was able to predict the ultimate tensile strength within 4%. PMID:26491719

  10. Notch Effect on Tensile Deformation Behavior of 304L and 316L Steels in Liquid Helium and Hydrogen

    NASA Astrophysics Data System (ADS)

    Shibata, K.; Fujii, H.

    2004-06-01

    Tensile tests of type 304L and 316L steels were carried out using round bar specimens with a notch in liquid helium, hydrogen, liquid nitrogen and at ambient temperature. The obtained tensile strengths were compared with the tensile strengths of smooth specimens. For smooth specimens, tensile strength increased with a decrease in temperature and the strengths in liquid helium and hydrogen show similar values in both steels. For notched specimen of 304L steel, tensile strength (including fracture strength) increased noticeably from ambient to liquid nitrogen temperature but showed a large decrease in liquid helium and hydrogen. In liquid hydrogen and helium, the tensile strength is a little lower in liquid hydrogen than in liquid helium and both strengths are lower than tensile strengths of smooth specimens. For notched specimen of 316L steel, an increase in tensile strength from ambient to liquid nitrogen temperature was not so large and a decrease from liquid nitrogen to liquid hydrogen was small. The tensile strengths in liquid helium and hydrogen were nearly same and higher than those of smooth specimens. Different behavior of serration was observed between liquid helium and hydrogen, and between 304L and 316L steels. The reasons for these differences were discussed using computer simulation.

  11. Notch Effect on Tensile Deformation Behavior of 304L and 316L Steels in Liquid Helium and Hydrogen

    SciTech Connect

    Shibata, K.; Fujii, H.

    2004-06-28

    Tensile tests of type 304L and 316L steels were carried out using round bar specimens with a notch in liquid helium, hydrogen, liquid nitrogen and at ambient temperature. The obtained tensile strengths were compared with the tensile strengths of smooth specimens. For smooth specimens, tensile strength increased with a decrease in temperature and the strengths in liquid helium and hydrogen show similar values in both steels. For notched specimen of 304L steel, tensile strength (including fracture strength) increased noticeably from ambient to liquid nitrogen temperature but showed a large decrease in liquid helium and hydrogen. In liquid hydrogen and helium, the tensile strength is a little lower in liquid hydrogen than in liquid helium and both strengths are lower than tensile strengths of smooth specimens. For notched specimen of 316L steel, an increase in tensile strength from ambient to liquid nitrogen temperature was not so large and a decrease from liquid nitrogen to liquid hydrogen was small. The tensile strengths in liquid helium and hydrogen were nearly same and higher than those of smooth specimens. Different behavior of serration was observed between liquid helium and hydrogen, and between 304L and 316L steels. The reasons for these differences were discussed using computer simulation.

  12. Tensile properties of vanadium-base alloys with a tungsten/inert-gas weld zone

    SciTech Connect

    Loomis, B.A.; Konicek, C.F.; Nowicki, L.J.; Smith, D.L.

    1992-12-31

    The tensile properties of V-(0-20)Ti and V-(O-15)Cr-5Ti alloys after butt-joining by tungsten/inert-gas (TIG) welding were determined from tests at 25{degrees}C. Tensile tests were conducted on both annealed and cold-worked materials with a TIG weld zone. The tensile properties of these materials were strongly influenced by the microstructure in the heat-affected zone adjacent to the weld zone and by the intrinsic fracture toughness of the alloys. TIG weld zones in these vanadium-base alloys had tensile properties comparable to those of recrystallized alloys without a weld zone. Least affected by the TIG welding were tensile properties of the V-5Ti and V-5Cr-5Ti alloys. Although the tensile properties of the V-5Ti and V- 5Cr-5Ti alloys with a TIG weld zone were acceptable for structural material, these properties would be improved by optimization of the welding parameters for minimum grain size in the heat-affected zone.

  13. Dynamic-Tensile-Extrusion of Polyurea

    NASA Astrophysics Data System (ADS)

    Furmanski, Jevan; Cady, Carl; Rae, Philip; Trujillo, Carl; Gray, G. T., III; Brown, Eric

    2011-06-01

    Polyurea was investigated under Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) loading where spherical projectiles were propelled at 440-509 m/s through an extrusion die with an area reduction of 87%. Momentum of the leading edge imposes a rapid tensile deformation on the extruding material. Polyurea is an elastomer with outstanding high-rate tensile performance of interest in the shock regime. Previous Dyn-Ten-Ext work on semi-crystalline polymers (PTFE, PCTFE) resulted in small-scale fragmentation of the polymer, and did not provide clear information on the evolution of tensile damage in those materials. The polyurea behaved very differently; the polymer first extruded a jet of apparently intact material, which then broke down via void formation and coalescence, followed by fibrillation and tearing of the material. Most of the material in the jet elastically retracted back into the die, and only a few fragments of torn material were liberated from the sample. The surface texture of all failed surfaces was rough indicating a considerable amount of energy was absorbed by sub-critical failure mechanisms. It is interesting to note that while damage nucleation appeared pervasive in the extruded jet, the samples were nevertheless recovered largely intact, with limited fragmentation.

  14. Tensile Behavior of Single-Crystal Tin Whiskers

    NASA Astrophysics Data System (ADS)

    Singh, S. S.; Sarkar, R.; Xie, H.-X.; Mayer, C.; Rajagopalan, J.; Chawla, N.

    2014-04-01

    The growth of metallic (predominantly Sn) whiskers from pure metallic platings has been studied for over 50 years. While the phenomenon of Sn whiskering has been studied for decades, very little is known about the mechanical properties of these materials. This can be attributed to the difficulty in handling, gripping, and testing such fine-diameter and high-aspect-ratio whiskers. We report on the stress-strain behavior of Sn whiskers inside a dual-beam focused ion beam (FIB) with a scanning electron microscope (SEM). Lift-out of the whiskers was conducted in situ in the FIB, and the whiskers were tested using a microelectromechanical system tensile testing stage. Using this technique, the whiskers had minimum exposure to ambient air and were not handled by hand. SEM images after fracture enabled reliable calculation of the whisker cross-sectional area. Tests on two different whiskers revealed relatively high tensile strengths of 720 MPa and 880 MPa, respectively, and a limited strain to failure of ˜2% to 3%. For both whiskers, the Young's modulus was between 42 GPa and 45 GPa. It is interesting to note that the whiskers were quite strong and had limited ductility. These findings are intriguing and provide a basis for further work to understand the effect of Sn whisker mechanical properties on short circuits in electronics.

  15. Lifetimes of fiber composites under sustained tensile loading

    NASA Technical Reports Server (NTRS)

    Chiao, T. T.; Sherry, R. J.; Chiao, C. C.

    1977-01-01

    Results are presented for a study intended to summarize lifetime data on several fiber/epoxy composite materials subjected to sustained uniaxial tensile loading, to report preliminary results of an accelerated test method for predicting the life of simple composites, and to describe related work in progress on pressure vessels and other filament-wound structures. The lifetime performance of the tested composites was compared by plotting the percent of ultimate strength (applied fiber stress normalized with respect to fiber failure stress in a composite) versus lifetime. In terms of performance in long-term tensile applications, the tested composites are ranked in the following order: graphite/epoxy, Be wire/epoxy, Aramid/epoxy, and S-glass/epoxy. The accelerated test using temperature and stress to simulate the passage of time proves to be encouraging, at least in the case of the Aramid/epoxy composite. The potential of a statistical analysis based on Weibull distribution analyses or a power law relationship is demonstrated.

  16. An Assessment of Variability in the Average Tensile Properties of a Melt-Infiltrated SiC/SiC Composite

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Brewer, David N.; Calomino, Anthony M.

    2004-01-01

    Woven SiC/SiC Ceramic Matrix Composites (CMCs), manufactured by the slurry-cast, melt-infiltration process are under consideration as combustor liner materials in aircraft gas turbine engines. Tensile properties (elastic modulus, proportional limit strength, in-plane tensile strength and strain to failure) of the CMC, manufactured during two separate time periods (9/99 and 1/01) were determined at 816 and 1024 C by conducting tensile tests on specimens machined from the CMC plates. A total of 24 tensile tests were conducted for each temperature and CMC variant combination. In this study average tensile properties of the two cMC variants were statistically compared to evaluate significant differences, if any, within the CMC's properties.

  17. Tensile Properties of Poly (N-vinyl caprolactam) Gels

    NASA Technical Reports Server (NTRS)

    Morgret, Leslie D.; Hinkley, Jeffrey A.

    2004-01-01

    N-vinyl caprolactam was copolymerized with ethylene glycol dimethacrylate using a free-radical initiator in alcohol/water solution. The resulting gels were thermally-responsive in water, undergoing an approximate fivefold reversible volume shrinkage between room temperature and ca. 50 C. Tensile testing showed that the stress-strain behavior was qualitatively different in the collapsed state above the temperature-induced transition. At the higher temperature, gels were stiffer, more ductile, and showed greater time dependence. Implications for the design of gel actuators are briefly discussed.

  18. Effects of static tensile load on the thermal expansion of Gr/PI composite material

    NASA Technical Reports Server (NTRS)

    Farley, G. L.

    1981-01-01

    The effect of static tensile load on the thermal expansion of Gr/PI composite material was measured for seven different laminate configurations. A computer program was developed which implements laminate theory in a piecewise linear fashion to predict the coupled nonlinear thermomechanical behavior. Static tensile load significantly affected the thermal expansion characteristics of the laminates tested. This effect is attributed to a fiber instability micromechanical behavior of the constituent materials. Analytical results correlated reasonably well with free thermal expansion tests (no load applied to the specimen). However, correlation was poor for tests with an applied load.

  19. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints

    PubMed Central

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-01-01

    Statement of the Problem Soldering is a process commonly used in fabricating dental prosthesis. Since most soldered prosthesis fail at the solder joints; the joint strength is of utmost importance. Purpose The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. Materials and Method A total number of 40 Ni-Cr samples were fabricated according to ADA/ISO 9693 specifications for tensile test. Samples were cut at the midpoint of the bar, and were placed at the considered angles by employing an explicitly designed device. They were divided into 4 groups regarding the gap angle; Group C (control group) with parallel gap on steady distance of 0.2mm, Group 1: 10°, Group 2: 20°, and Group3: 30° gap angles. When soldered, the specimens were all tested for tensile strength using a universal testing machine at a cross-head speed of 0.5 mm/min with a preload of 10N. Kruskal-Wallis H test was used to compare tensile strength among the groups (p< 0.05). Results The mean tensile strength values obtained from the study groups were respectively 307.84, 391.50, 365.18, and 368.86 MPa. The tensile strength was not statistically different among the four groups in general (p≤ 0.490). Conclusion Making the gap angular at the solder joints and the subsequent unsteady increase of the gap distance would not change the tensile strength of the joint. PMID:26636118

  20. Validation of the U.S. NRC NGNP evaluation model with the HTTR

    SciTech Connect

    Saller, T.; Seker, V.; Downar, T.

    2012-07-01

    The High Temperature Test Reactor (HTTR) was modeled with TRITON/PARCS. Traditional light water reactor (LWR) homogenization methods rely on the short mean free paths of neutrons in LWR. In gas-cooled, graphite-moderated reactors like the HTTR neutrons have much longer mean free paths and penetrate further into neighboring assemblies than in LWRs. Because of this, conventional lattice calculations with a single assembly may not be valid. In addition to difficulties caused by the longer mean free paths, the HTTR presents unique axial and radial heterogeneities that require additional modifications to the single assembly homogenization method. To handle these challenges, the homogenization domain is decreased while the computational domain is increased. Instead of homogenizing a single hexagonal fuel assembly, the assembly is split into six triangles on the radial plane and five blocks axially in order to account for the placement of burnable poisons. Furthermore, the radial domain is increased beyond a single fuel assembly to account for spectrum effects from neighboring fuel, reflector, and control rod assemblies. A series of five two-dimensional cases, each closer to the full core, were calculated to evaluate the effectiveness of the homogenization method and cross-sections. (authors)

  1. Tensile behavior of irradiated manganese-stabilized stainless steel

    SciTech Connect

    Klueh, R.L.

    1996-10-01

    Tensile tests were conducted on seven experimental, high-manganese austenitic stainless steels after irradiation up to 44 dpa in the FFTF. An Fe-20Mn-12Cr-0.25C base composition was used, to which various combinations of Ti, W, V, B, and P were added to improve strength. Nominal amounts added were 0.1% Ti, 1% W, 0.1% V, 0.005% B, and 0.03% P. Irradiation was carried out at 420, 520, and 600{degrees}C on the steels in the solution-annealed and 20% cold-worked conditions. Tensile tests were conducted at the irradiation temperature. Results were compared with type 316 SS. Neutron irradiation hardened all of the solution-annealed steels at 420, 520, and 600{degrees}C, as measured by the increase in yield stress and ultimate tensile strength. The steel to which all five elements were added to the base composition showed the least amount of hardening. It also showed a smaller loss of ductility (uniform and total elongation) than the other steels. The total and uniform elongations of this steel after irradiation at 420{degrees}C was over four times that of the other manganese-stabilized steels and 316 SS. There was much less difference in strength and ductility at the two higher irradiation temperatures, where there was considerably less hardening, and thus, less loss of ductility. In the cold-worked condition, hardening occured only after irradiation at 420{degrees}C, and there was much less difference in the properties of the steels after irradiation. At the 420{degrees}C irradiation temperature, most of the manganese-stabilized steels maintained more ductility than the 316 SS. After irradiation at 420{degrees}C, the temperature of maximum hardening, the steel to which all five of the elements were added had the best uniform elongation.

  2. Increased tensile strength of carbon nanotube yarns and sheets through chemical modification and electron beam irradiation.

    PubMed

    Miller, Sandi G; Williams, Tiffany S; Baker, James S; Solá, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S; Wilmoth, Nathan G; Gaier, James; Chen, Michelle; Meador, Michael A

    2014-05-14

    The inherent strength of individual carbon nanotubes (CNTs) offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of CNT forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated into that of sheets and yarns, where the bulk material strength is limited by intertube electrostatic attractions and slippage. The focus of this work was to assess postprocessing of CNT sheets and yarns to improve the macro-scale strength of these material forms. Both small-molecule functionalization and electron-beam irradiation were evaluated as means to enhance the tensile strength and Young's modulus of the bulk CNT materials. Mechanical testing revealed a 57% increase in tensile strength of CNT sheets upon functionalization compared with unfunctionalized sheets, while an additional 48% increase in tensile strength was observed when functionalized sheets were irradiated. Similarly, small-molecule functionalization increased tensile strength of yarn by up to 25%, whereas irradiation of the functionalized yarns pushed the tensile strength to 88% beyond that of the baseline yarn. PMID:24720450

  3. Increased Tensile Strength of Carbon Nanotube Yarns and Sheets through Chemical Modification and Electron Beam Irradiation

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G.; Williams, Tiffany S.; Baker, James S.; Sola, Francisco; Lebron-Colon, Marisabel; McCorkle, Linda S.; Wilmoth, Nathan G.; Gaier, James; Chen, Michelle; Meador, Michael A.

    2014-01-01

    The inherent strength of individual carbon nanotubes offers considerable opportunity for the development of advanced, lightweight composite structures. Recent work in the fabrication and application of carbon nanotube (CNT) forms such as yarns and sheets has addressed early nanocomposite limitations with respect to nanotube dispersion and loading; and has pushed the technology toward structural composite applications. However, the high tensile strength of an individual CNT has not directly translated to macro-scale CNT forms where bulk material strength is limited by inter-tube electrostatic attraction and slippage. The focus of this work was to assess post processing of CNT sheet and yarn to improve the macro-scale strength of these material forms. Both small molecule functionalization and e-beam irradiation was evaluated as a means to enhance tensile strength and Youngs modulus of the bulk CNT material. Mechanical testing results revealed a tensile strength increase in CNT sheets by 57 when functionalized, while an additional 48 increase in tensile strength was observed when functionalized sheets were irradiated; compared to unfunctionalized sheets. Similarly, small molecule functionalization increased yarn tensile strength up to 25, whereas irradiation of the functionalized yarns pushed the tensile strength to 88 beyond that of the baseline yarn.

  4. Static and dynamic tensile behaviour of aluminium processed by high pressure torsion

    NASA Astrophysics Data System (ADS)

    Verleysen, Patricia; Oelbrandt, Wouter; Naghdy, Soroosh; Kestens, Leo

    2015-09-01

    High pressure torsion (HPT) is a severe plastic deformation technique in which a small, disk-like sample is subjected to a torsional deformation under a high hydrostatic pressure. In present study, the static and dynamic tensile behaviour of commercially pure aluminium (99.6 wt%) processed by HPT is studied. The high strain rate tensile behaviour is characterized using a purpose-developed miniature split Hopkinson tensile bar setup by which strain rates up to 5 × 103 s-1 can be reached. During the tests, the deformation of a speckle pattern applied to the samples is recorded, by which local information on the strain is obtained using a digital image correlation technique. Electron back scatter diffraction images are used to investigate the microstructural evolution, more specifically the grain refinement obtained by HPT. The fracture surfaces of the tensile samples are studied by scanning electron microscopy. Results show that the imposed severe plastic deformation significantly increases the tensile strength, however, at the expense of ductility. The strain rate only has a minor influence on the materials tensile behaviour.

  5. Characterization of Optical Fiber Strength Under Applied Tensile Stress and Bending Stress

    SciTech Connect

    P.E. Klingsporn

    2011-08-01

    Various types of tensile testing and bend radius tests were conducted on silica core/silica cladding optical fiber of different diameters with different protective buffer coatings, fabricated by different fiber manufacturers. The tensile tests were conducted to determine not only the average fiber strengths at failure, but also the distribution in fracture strengths, as well as the influence of buffer coating on fracture strength. The times-to-failure of fiber subjected to constant applied bending stresses of various magnitudes were measured to provide a database from which failure times of 20 years or more, and the corresponding minimum bend radius, could be extrapolated in a statistically meaningful way. The overall study was done to provide an understanding of optical fiber strength in tensile loading and in applied bending stress as related to applications of optical fiber in various potential coizfgurations for weapons and enhanced surveillance campaigns.

  6. Relationship between fractional porosity and tensile strength for high-porosity sintered ferrous powder compacts

    SciTech Connect

    Baron, R.P.; Wawner, F.E.; Wert, J.A.

    1998-07-03

    The current study examines the mechanical properties of pressed and sintered ferrous powder metallurgy compacts with low relative densities, between 0.6 and 0.8. Three different powder particle compositions were investigated: eutectoid steel, stainless steel, and stainless tool steel compacts. To obtain information concerning the tensile properties of these low-density compacts, simple tensile tests were performed. In addition, Vickers microhardness tests were performed on metallographic sections of the tensile bars. The results from these tests are used to compare the measured relative strength values with estimates generated by previously published models. Also, the fracture surfaces of selected compacts were examined in the scanning electron microscope to obtain information concerning the fracture process.

  7. Fracture of Open-Cell Nickel Foams Under Quasi-Static Tensile Loading

    NASA Astrophysics Data System (ADS)

    Shehata Aly, Mohamed

    2010-12-01

    Open-cell nickel foams with average pore size of 600 μm have been subjected to room temperature tensile tests to explore their tensile properties. Using a state of the art extensometer of noncontact type, foam properties as ultimate tensile strength, yield strength, and the Young's modulus ( E) have been measured accurately. The reason behind the usage of this kind of extensometer is to avoid completely any minor deformation that might be caused by the attachment of conventional extensometer to the sample's surface prior to testing. The function of this extensometer is based on the usage of a laser (CCD) camera that detects and records the dimensional changes as soon as the load is applied. A series of cyclic loading-unloading tests was performed to determine the foam's Young's modulus. The fracture behavior of foam cells was observed to be ductile. Complete separation of struts or cell walls took place successively by necking.

  8. Tensile and impact properties of General Atomics 832864 heat of V-4Cr-4Ti alloy

    SciTech Connect

    Tsai, H.; Nowicki, L.J.; Gazda, J.; Billone, M.C.; Smith, D.L.; Johnson, W.R.; Trester, P.

    1998-09-01

    A 1300-kg heat of V-4Cr-4Ti alloy was procured by General Atomics (GA) for the DIII-D radiative divertor program. To determine the mechanical properties of this alloy, tensile and Charpy tests were conducted on specimens prepared from pieces of 4.8-mm-thick as-rolled plates, a major product form for the DIII-D application. The tensile tests were conducted at three temperatures, 26, 280 and 380 C, the last two being the anticipated peak temperatures during DIII-D boronization and postvent bake-out, respectively. Results from these tests show that the tensile and impact properties of the 832864 heat are comparable to those of the other smaller V-(4-5)Cr-(4-5)Ti alloy heats previously developed by the US Fusion Materials Program and that scale-up of vanadium alloy production can be successfully achieved as long as reasonable process control is implemented.

  9. Effect of oxygen and oxidation on tensile behavior of V-5Cr-5Ti

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1996-04-01

    Oxidation studies were conducted on V-5Cr-5Ti alloy specimens in an air environment to evaluate the oxygen uptake of the alloy as a function of temperature and exposure time. The oxidation rates calculated from parabolic kinetic measurements of thermogravimetric testing and confirmed by microscopic analyses of cross sections of exposed specimens were 5, 17, and 27 {mu}m per year after exposure at 300, 400, and 500{degrees}C, respectively. Uniaxial tensile tests were conducted at room temperature and at 500{degrees}C on preoxidized specimens of the alloy to examine the effects of oxidation and oxygen migration on tensile strength and ductility. Microstructural characteristics of several of the tested specimens were determined by electron optics techniques. Correlations were developed between tensile strength and ductility of the oxidized alloy and microstructural characteristics such as oxide thickness, depth of hardened layer, depth on intergranular fracture zone, and transverse crack length.

  10. Sample selection, preparation methods, and the apparent tensile properties of silkworm (B. mori) cocoon silk.

    PubMed

    Reed, Emily J; Bianchini, Lindsay L; Viney, Christopher

    2012-06-01

    Reported literature values of the tensile properties of natural silk cover a wide range. While much of this inconsistency is the result of variability that is intrinsic to silk, some is also a consequence of differences in the way that silk is prepared for tensile tests. Here we explore how measured mechanical properties of Bombyx mori cocoon silk are affected by two intrinsic factors (the location from which the silk is collected within the cocoon, and the color of the silk), and two extrinsic factors (the storage conditions prior to testing, and different styles of reeling the fiber). We find that extrinsic and therefore controllable factors can affect the properties more than the intrinsic ones studied. Our results suggest that enhanced inter-laboratory collaborations, that lead to standardized sample collection, handling, and storage protocols prior to mechanical testing, would help to decrease unnecessary (and complicating) variation in reported tensile properties. PMID:22057343

  11. Designing tensile ductility in metallic glasses

    PubMed Central

    Sarac, Baran; Schroers, Jan

    2013-01-01

    Effectiveness of a second phase in metallic glass heterostructures to improve mechanical properties varies widely. Unfortunately, methods to fabricate such heterostructures like foams and composites do not allow controlled variation of structural features. Here we report a novel strategy, which allows us to vary heterostructural features independently, thereby enabling a systematic and quantitative study. Our approach reveals the optimal microstructural architecture for metallic glass heterostructures to achieve tensile ductility. Critical design aspect is a soft second phase, which is most effective when spacing between the second phase assumes the critical crack length of the metallic glass. This spacing should coincide with the second phase’s size, and beyond, the specific second phase morphology of the heterostructure is crucial. These toughening strategies are only effective in samples that are large compared with the spacing of the second phase. The identified design aspects provide guidance in designing tensile ductility into metallic glasses. PMID:23863967

  12. Designing tensile ductility in metallic glasses.

    PubMed

    Sarac, Baran; Schroers, Jan

    2013-01-01

    Effectiveness of a second phase in metallic glass heterostructures to improve mechanical properties varies widely. Unfortunately, methods to fabricate such heterostructures like foams and composites do not allow controlled variation of structural features. Here we report a novel strategy, which allows us to vary heterostructural features independently, thereby enabling a systematic and quantitative study. Our approach reveals the optimal microstructural architecture for metallic glass heterostructures to achieve tensile ductility. Critical design aspect is a soft second phase, which is most effective when spacing between the second phase assumes the critical crack length of the metallic glass. This spacing should coincide with the second phase's size, and beyond, the specific second phase morphology of the heterostructure is crucial. These toughening strategies are only effective in samples that are large compared with the spacing of the second phase. The identified design aspects provide guidance in designing tensile ductility into metallic glasses. PMID:23863967

  13. Tensile Instability in a Thick Elastic Body.

    PubMed

    Overvelde, Johannes T B; Dykstra, David M J; de Rooij, Rijk; Weaver, James; Bertoldi, Katia

    2016-08-26

    A range of instabilities can occur in soft bodies that undergo large deformation. While most of them arise under compressive forces, it has previously been shown analytically that a tensile instability can occur in an elastic block subjected to equitriaxial tension. Guided by this result, we conducted centimeter-scale experiments on thick elastomeric samples under generalized plane strain conditions and observed for the first time this elastic tensile instability. We found that equibiaxial stretching leads to the formation of a wavy pattern, as regions of the sample alternatively flatten and extend in the out-of-plane direction. Our work uncovers a new type of instability that can be triggered in elastic bodies, enlarging the design space for smart structures that harness instabilities to enhance their functionality. PMID:27610857

  14. Silphenylene elastomers have high thermal stability and tensile strength

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Two polymeric silphenylene ethers, when cured by reactions with ethyl silicates and metal salts at room temperature, form elastomers having excellent thermal stability and tensile properties. The highest tensile strength obtained in a reinforced elastomer was 2800 psi.

  15. Effects of temperature and strain rate on the tensile behaviors of SIMP steel in static lead bismuth eutectic

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Yan, Wei; Sha, Wei; Wang, Wei; Shan, Yiyin; Yang, Ke

    2016-05-01

    In order to assess the susceptibility of candidate structural materials to liquid metal embrittlement, this work investigated the tensile behaviors of ferritic-martensitic steel in static lead bismuth eutectic (LBE). The tensile tests were carried out in static lead bismuth eutectic under different temperatures and strain rates. Pronounced liquid metal embrittlement phenomenon is observed between 200 °C and 450 °C. Total elongation is reduced greatly due to the liquid metal embrittlement in LBE environment. The range of ductility trough is larger under slow strain rate tensile (SSRT) test.

  16. 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

  17. Tensile strength of SiC fibers

    SciTech Connect

    Zok, F.W.; Chen, X.; Weber, C.H.

    1995-07-01

    An experimental investigation has been conducted on the effects of gauge length on the tensile strength of SiC fibers. The results show that the overall strength distribution cannot be described solely in terms of the two-parameter Weibull function. The overall distribution is found to be consistent with two concurrent flaw populations, one of them being characteristic of the pristine fibers, and the other characteristic of the additional flaws introduced into the fiber during processing of the composite.

  18. Tunable Tensile Ductility in Metallic Glasses

    PubMed Central

    Magagnosc, D. J.; Ehrbar, R.; Kumar, G.; He, M. R.; Schroers, J.; Gianola, D. S.

    2013-01-01

    Widespread adoption of metallic glasses (MGs) in applications motivated by high strength and elasticity combined with plastic-like processing has been stymied by their lack of tensile ductility. One emerging strategy to couple the attractive properties of MGs with resistance to failure by shear localization is to employ sub-micron sample or feature length scales, although conflicting results shroud an atomistic understanding of the responsible mechanisms in uncertainty. Here, we report in situ deformation experiments of directly moulded Pt57.5Cu14.7Ni5.3P22.5 MG nanowires, which show tunable tensile ductility. Initially brittle as-moulded nanowires can be coerced to a distinct glassy state upon irradiation with Ga+ ions, leading to tensile ductility and quasi-homogeneous plastic flow. This behaviour is reversible and the glass returns to a brittle state upon subsequent annealing. Our results suggest a novel mechanism for homogenous plastic flow in nano-scaled MGs and strategies for circumventing the poor damage tolerance that has long plagued MGs.

  19. MISSE 6 Polymer Film Tensile Experiment

    NASA Technical Reports Server (NTRS)

    Miller, Sharon K. R.; Dever, Joyce A.; Banks, Bruce A.; Waters, Deborah L.; Sechkar, Edward; Kline, Sara

    2010-01-01

    The Polymer Film Tensile Experiment (PFTE) was flown as part of Materials International Space Station Experiment 6 (MISSE 6). The purpose of the experiment was to expose a variety of polymer films to the low Earth orbital environment under both relaxed and tension conditions. The polymers selected are those commonly used for spacecraft thermal control and those under consideration for use in spacecraft applications such as sunshields, solar sails, and inflatable and deployable structures. The dog-bone shaped samples of polymers that were flown were exposed on both the side of the MISSE 6 Passive Experiment Container (PEC) that was facing into the ram direction (receiving atomic oxygen, ultraviolet (UV) radiation, ionizing radiation, and thermal cycling) and the wake facing side (which was supposed to have experienced predominantly the same environmental effects except for atomic oxygen which was present due to reorientation of the International Space Station). A few of the tensile samples were coated with vapor deposited aluminum on the back and wired to determine the point in the flight when the tensile sample broke as recorded by a change in voltage that was stored on battery powered data loggers for post flight retrieval and analysis. The data returned on the data loggers was not usable. However, post retrieval observation and analysis of the samples was performed. This paper describes the preliminary analysis and observations of the polymers exposed on the MISSE 6 PFTE.

  20. Through-the-thickness tensile strength of textile composites

    NASA Technical Reports Server (NTRS)

    Jackson, Wade C.; Ifju, Peter G.

    1994-01-01

    A series of tests was run to characterize the through-the-thickness tensile strength for a variety of composites that included 2D and 3D braids, 2D and 3D weaves, and prepreg tapes. A new test method based on a curved beam was evaluated. The through-the-thickness deformations were characterized using moire interferometry. Failures were significantly different between the 2D and 3D materials. The 2D materials delaminated between layers due to out-of-plane tensile stresses. The strength of the 2D textile composites did not increase relative to the tapes. The 3D materials failed due to the formation of radial cracks caused by high circumferential stresses along the inner radius. A circumferential crack similar to the 2D materials produced the final failure. Final failure in the 3D materials occurred at a lower bending moment than in other materials. The early failures were caused by radial crack formation rather than low through-the-thickness strength.

  1. 49 CFR 230.26 - Tensile strength of shell plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Tensile strength of shell plates. 230.26 Section 230.26 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Appurtenances Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength...

  2. 49 CFR 230.26 - Tensile strength of shell plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of... 49 Transportation 4 2013-10-01 2013-10-01 false Tensile strength of shell plates. 230.26...

  3. 49 CFR 230.26 - Tensile strength of shell plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of... 49 Transportation 4 2012-10-01 2012-10-01 false Tensile strength of shell plates. 230.26...

  4. 49 CFR 230.26 - Tensile strength of shell plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of... 49 Transportation 4 2010-10-01 2010-10-01 false Tensile strength of shell plates. 230.26...

  5. 49 CFR 230.26 - Tensile strength of shell plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Strength of Materials § 230.26 Tensile strength of shell plates. When the tensile strength of... 49 Transportation 4 2014-10-01 2014-10-01 false Tensile strength of shell plates. 230.26...

  6. Wear-Lines and Split-Lines of Human Patellar Cartilage: Relation to Tensile Biomechanical Properties

    PubMed Central

    Bae, Won C.; Wong, Van W.; Hwang, Jennifer; Antonacci, Jennifer M.; Nugent-Derfus, Gayle E.; Blewis, Megan E.; Temple-Wong, Michele M.; Sah, Robert L.

    2008-01-01

    Background Articular cartilage undergoes age-associated degeneration, resulting in both structural and functional biomechanical changes. At early stages of degeneration, wear-lines develop in the general direction of joint movement. With aging, cartilage exhibits a decrease in tensile modulus. The tensile modulus of cartilage has also been related to the orientation of the collagen network, as revealed by split-lines. Objective To determine the relative contribution of wear-line and split-line orientation on the tensile biomechanical properties of human patellar cartilage from different depths. Methods In human patellar cartilage, wear- and split-lines are aligned parallel to each other at the proximal facet, and perpendicular to each other at the medial facet. Using superficial, middle, and deep cartilage sections from these two sites, tensile samples were prepared in two orthogonal orientations. Thus, for each depth, there were four groups of samples, with their long axes were aligned either parallel or perpendicular to wear-line direction and also aligned parallel or perpendicular to split-line direction. Uniaxial tensile tests were performed to assess equilibrium and ramp moduli. Results Tensile equilibrium modulus varied with wear-line orientation (p<0.05) and depth (p<0.001), in an interactive manner (p<0.05), and tended to vary with split-line orientation (p=0.16). In the superficial layer, equilibrium and ramp modulus was higher when the samples were loaded parallel to wear-lines (p<0.05). Conclusion These results indicate that mild wear (i.e., wear-line formation) at the articular surface has deleterious functional effects on articular cartilage and represents an early aging associated degenerative change. The identification and recognition of functional biomechanical consequences of wear-lines is useful for planning and interpreting tensile biomechanical tests in human articular cartilage. PMID:18248747

  7. Tensile strength of dome rocks and lavas at Santiaguito dome complex, Guatemala

    NASA Astrophysics Data System (ADS)

    Hornby, Adrian; Lamb, Oliver; Lamur, Anthony; Lavallée, Yan

    2015-04-01

    Lava domes are inherently unstable structures, subject to intense gas flux and rapid variations in the state of stress. At shallow depths confining stresses are minimal and deformation is dilatant, occurring predominantly through tensile fractures. This fracture mode facilitates outgassing and contributes to the development of gas-and-ash activity as well as vulcanian eruptions. However, there is a paucity of tensile strength data for volcanic materials in the published literature, and we know of no paper which addresses this at high temperatures. We study the tensile strength of dome rocks collected at the Santiaguito dome complex, Guatemala, over a porosity range of 3-25%. Indirect tensile (Brazilian) tests were conducted on 40-mm diameter cores, by imposing a compressive displacement rate (radial to the core) of 4 micron/s at room temperature as well as an eruptive temperature of ca. 850 °C. An acoustic monitoring system is employed to track the nucleation, propagation and coalescence of fractures leading to complete sample failure. We find that the rocks' tensile strength exhibits a nonlinear decrease with porosity. Preliminary tests at high temperature indicate that some rocks exhibit a higher tensile strength (than at room temperature); in these experiments, samples containing a higher fraction of interstitial melt revealed an additional component of viscous flow. Further experiments conducted at higher strain rates will define the brittle response of the liquid during tensile failure. The data is compared against similar datasets for volcanic rocks. We will discuss implications for shallow volcanic processes ranging from dilation bands and tuffisite formation to gas-and-ash explosions and dome structural stability.

  8. Tensile properties of reduced activation Fe-9Cr-2W steels after FFTF irradiation

    NASA Astrophysics Data System (ADS)

    Kurishita, H.; Kayano, H.; Narui, M.; Kimura, A.; Hamilton, M. L.; Gelles, D. S.

    1994-09-01

    In order to develop radiation resistant steels with reduced activation for fusion reactor applications, the effect of fast neutron irradiation was investigated on the tensile properties of five types of Fe-9Cr-2W martensitic steel with and without small additions of boron, yttrium and aluminum. Miniature tensile specimens of the steels were irradiated to 28 dpa at 663 K and 33-35 dpa at 703, 793 and 873 K in the Fast Flux Test Facility (FFTF) and were deformed at temperatures between 300 and 873 K. The yield and ultimate tensile stresses were not significantly affected by the irradiations, but the total elongation was considerably decreased by the irradiation at 663 K. The reduction in elongation depended strongly on the test temperature with a maximum at around 673 K. The addition of yttrium alone tended to increase the high temperature strength, while the simultaneous addition of yttrium and aluminum tended to decrease the total elongation.

  9. Tensile properties of V-5Cr-5Ti alloy after exposure in air environment

    SciTech Connect

    Natesan, K.; Soppet, W.K.

    1997-04-01

    Oxidation studies were conducted on V-5Cr-5Ti alloy specimens in an air environment to evaluate the oxygen uptake behavior of the alloy as a function of temperature and exposure time. The oxidation rates, calculated from parabolic kinetic measurements of thermogravimetric testing and confirmed by microscopic analysis of cross sections of exposed specimens, were 5, 17, and 27 {mu}m per year after exposure at 300, 400, and 500{degrees}C, respectively. Uniaxial tensile tests were conducted at room temperature and at 500{degrees}C on preoxidized specimens of the alloy to examine the effects of oxidation and oxygen migration on tensile strength and ductility. Correlations were developed between tensile strength and ductility of the oxidized alloy and microstructural characteristics such as oxide thickness, depth of hardened layer, depth of intergranular fracture zone, and transverse crack length.

  10. Effect of irradiation on the tensile properties of niobium-base alloys

    SciTech Connect

    Grossbeck, M.L.; Heestand, R.L.; Atkin, S.D.

    1986-11-01

    The alloys Nb-1Zr and PWC-11 (Nb-1Zr-0.1C) were selected as prime candidate alloys for the SP-100 reactor. Since the mechanical properties of niobium alloys irradiated to end-of-life exposure levels of about 2 x 10SW neutrons/mS (E > 0.1 MeV) at temperatures above 1300 K were not available, an irradiation experiment (B-350) in EBR-II was conducted. Irradiation creep, impact properties, bending fatigue, and tensile properties were investigated; however, only tensile properties will be reported in this paper. The tensile properties were studied since they easily reveal the common irradiation phenomena of hardening and embrittlement. Most attention was directed to testing at the irradiation temperature. Further testing was conducted at lower temperatures in order to scope the behavior of the alloys in cooldown conditions.

  11. Grain boundary sliding measurements during tensile creep of a single-phase alumina

    SciTech Connect

    Blanchard, C.R.; Lin, H.T.; Becher, P.F.

    1998-06-01

    The grain boundary sliding (GBS) behavior of a single-phase (relatively coarse-grained) alumina material was studied after tensile creep experiments were performed at 1,500 C at stress levels of 20 and 35 MPa. Specimens tested at 35 MPa exhibited a number of modes of GBS, including Mode II (shear) displacements, Mode I (opening) displacements, out-of-plane sliding displacements, and in-plane grain rotation. Strains in the grain boundaries due to Mode II GBS displacements ranged from 940% to 4,400%. Average Mode II GBS displacements ranged from 0.08 to 0.28 {micro}m in samples tested for 120 and 480 min, respectively, at 35 MPa. The GBS displacements were shown to fit a Weibull distribution. Tensile creep under a 35 MPa stress yielded a GBS rate of 9.5 {times} 10{sup {minus}6} {micro}m/s, while the 20 MPa stress resulted in a GBS rate of 2.2 {times} 10{sup {minus}6} {micro}m/s. The average Mode II GBS displacements increased linearly with specimen strain, suggesting that GBS may play an important role in creep cavitation during tensile creep. The data also revealed that compatibility and constraint rules appear to govern GBS behavior during tensile creep. GBS behavior during compressive creep will be compared to the tensile creep GBS measurements presented.

  12. Tensile and tear strength of carrageenan film from Philippine eucheuma species.

    PubMed

    Briones, Annabelle V; Ambal, Wilhelmina O; Estrella, Romulo R; Pangilinan, Rolando; De Vera, Carlos J; Pacis, Raymund L; Rodriguez, Ner; Villanueva, Merle A

    2004-01-01

    The tensile and tear strength of carrageenan film from Philippines Eucheuma species were investigated using NEC tensilon universal-testing machine according to American Society for Testing Materials methods. These properties are important for assessing carrageenan film as packaging material. The kappa and iota types were used in the study. The effect of glycerine on the tensile and tear strength including elongation was also evaluated. Addition of glycerine tended to lower the tensile strength of the film and increase its elongation properties including the tear strength. Carrageenan film without glycerine was much stronger. Glycerine made the film more flexible and easy to deform. The composite film of carrageenan and konjac gum did not exhibit elongation. It also showed higher tensile strength than did the composite film of carrageenan and xanthan gum. Compared with iota-type carrageenan film, kappa-type carrageenan film without glycerine was more comparable to low-density polyethylene (LDPE) film in terms of tensile strength as was the composite film of carrageenan-konjac gum. The kappa-type carrageenan film with glycerine was more comparable to LDPE film in terms of tear strength. The elongation reading for carrageenan film was lower than that for LDPE film. Morphologic studies showed that the carrageenan film had sets of pores distributed randomly at different places as compared to LDPE film. It also showed that the carrageenan film was more fibrous than LDPE film. PMID:15085409

  13. Ball Indentation Studies on the Effect of Nitrogen on the Tensile Properties of 316LN SS

    NASA Astrophysics Data System (ADS)

    Mathew, M. D.; Ganesh Kumar, J.; Ganesan, V.; Laha, K.

    2015-12-01

    Type 316L(N) stainless steel (SS) containing 0.02-0.03 wt% carbon and 0.06-0.08 wt% nitrogen is used as the major structural material for the components of fast reactors. Research is underway to improve the high-temperature mechanical properties of 316LN SS by increasing the nitrogen content in the steel above the level of 0.08 wt%. In this investigation, ball indentation (BI) technique was used to evaluate the effect of nitrogen content on the tensile properties of 316LN SS. BI tests were conducted on four different heats of 316LN SS containing 0.07, 0.11, 0.14 and 0.22 wt% nitrogen in the temperature range 300-923 K. The tensile properties such as yield strength and ultimate tensile strength increased with increase in nitrogen content at all the investigated temperatures. These results were consistent with the corresponding uniaxial tensile test results. These studies showed that BI technique can be used to optimize the chemical composition during alloy development by evaluating tensile properties with minimum volume of material.

  14. Lifetimes of fiber composites under sustained tensile loading

    NASA Technical Reports Server (NTRS)

    Chiao, T. T.; Sherry, R. J.; Chiao, C. C.

    1977-01-01

    A description is presented of the test techniques which have been used to apply sustained uniaxial tensile loading to fiber/epoxy composites. The fiber types used include S-glass, aramid, graphite, and beryllium wire. The applied load vs lifetime data for four composite materials are presented in graphs. Attention is given to a statistical analysis of data, a performance comparison of various composites, the age effect on the strength of composites, the applicability of the lifetime data to complex composites, and aspects of accelerated test method development. It is found that the lifetime of a composite under a sustained load varies widely. Depending on the composite system, the minimum life typically differs from the maximum life by a factor of 100 to 1000. It is in this connection recommended that a use of average life data should be avoided in serious design calculations.

  15. Incipient and Progressive Damage in Polyethylene Under Extreme Tensile Conditions

    SciTech Connect

    Furmanski, Jevan; Brown, Eric; Trujillo, Carl P.; Martinez, Daniel Tito; Gray, George T. III

    2012-06-07

    The Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) test was developed at LANL by Gray and coworkers to probe the tensile response of materials at large strains (>1) and high strain-rates (>1000/s) by firing projectiles through a conical die at 300-700 m/s. This technique has recently been applied to various polymers, such as the fluoropolymers PTFE (Teflon) and the chemically similar PCTFE, which respectively exhibited catastrophic fragmentation and distributed dynamic necking. This work details investigations of the Dyn-Ten-Ext response of high density polyethylene, both to failure and sub-critical conditions. At large extrusion ratios ({approx}7.4) and high velocities, such as those previously employed, HDPE catastrophically fragmented in a craze-like manner in the extruded jet. At more modest extrusion ratios and high velocities the specimen extruded a stable jet that ruptured cleanly, and at lower velocities was recovered intact after sustaining substantial internal damage. Thermomechanical finite element simulations showed that the damage corresponded to a locus of shear stress in the presence of hydrostatic tension. X-ray computed tomography corroborated the prediction of a shear damage mechanism by finding the region of partially damaged material to consist of macroscopic shear-mode cracks nearly aligned with the extrusion axis, originating from the location of damage inception.

  16. Human Annulus Fibrosus Dynamic Tensile Modulus Increases with Degeneration.

    PubMed

    Sen, Sounok; Jacobs, Nathan T; Boxberger, John I; Elliott, Dawn M

    2012-01-01

    The annulus fibrosus (AF) of the intervertebral disc experiences cyclic tensile loading in vivo at various states of mechanical equilibrium. Disc degeneration is associated with alterations in the biochemical composition of the AF including decreased water content, decreased proteoglycan concentration, and increased collagen deposition that affect mechanical function of the AF in compression and shear. Such changes may also affect the dynamic viscoelastic properties of the AF and thus alter the disc's ability to dissipate energy under physiologic loading. The objectives of this study were to quantify the dynamic viscoelastic properties of human AF in circumferential tension and to determine the effect of degeneration on these properties. Nondegenerated and degenerated human AF tensile samples were tested in uniaxial tension over a spectrum of loading frequencies spanning 0.01Hz to 2Hz at several states of equilibrium strain to determine the dynamic viscoelastic properties (dynamic modulus, phase angle) using a linear viscoelastic model. The AF dynamic modulus increased at higher equilibrium strain levels. The AF behaved more elastically at higher frequencies with a decreased phase angle. Degeneration resulted in a higher dynamic modulus at all strain levels but had no effect on phase angle. The findings from this study elucidate the effect of degeneration on the dynamic viscoelastic properties of human AF and lend insight into the mechanical role of the AF in cyclic loading conditions. PMID:22247579

  17. High temperature tensile deformation behavior of Grade 92 steel

    NASA Astrophysics Data System (ADS)

    Alsagabi, Sultan; Shrestha, Triratna; Charit, Indrajit

    2014-10-01

    Candidate structural materials for advanced reactors need to have superior high temperature strength and creep-rupture properties among other characteristics. The ferritic-martensitic Grade 92 steel (Fe-9Cr-2W-0.5Mo, wt.%) is considered such a candidate structural material. Tensile tests were performed at temperatures of 600, 650 and 700 °C in the strain rate range of 10-5-10-3 s-1. After analyzing the tensile results using the Bird-Mukherjee-Dorn (BMD) equation, a stress exponent of about 9.5 and an activation energy of about 646 kJ/mol were obtained. In the light of high values of the stress exponent and activation energy, the threshold stress concept was used to elucidate the operating high temperature deformation mechanism. As a result of this modification, the true activation energy and stress exponent of the high temperature deformation in Grade 92 steel were found to be about 245 kJ/mol and 5, respectively. Thus, the dominant high temperature deformation mechanism was identified as the high temperature climb of edge dislocations and the appropriate constitutive equation was developed.

  18. Effects of parachute-ribbon surface treatments on tensile strength

    SciTech Connect

    Auerbach, I.; Whinery, L.D.; Johnson, D.W.; Mead, K.E.; Sheldon, D.D.

    1986-01-01

    Routine quality-assurance evaluations of nylon ribbons used on test-deployed parachutes revealed tensile-strength degradation had occurred in some of the ribbons. The degradation occurred exclusively in some of the noncritical skirt ribbons with stenciled blue-ink identification markings. Although the strength loss was excessive, the reliability of the parachute was not affected. These results motivated an accelerated-aging study of the effects on tensile strength of not only the inks but also of the sizing chemicals that are used to coat fabrics in parachute construction. Nylon ribbons and Kevlar webbing were treated with these materials and stored both under ambient conditions and at 60/sup 0/C (140/sup 0/F) for periods of time up to eight months. Small increases in strength developed under ambient conditions whereas small decreases developed at elevated temperatures. Samples stored in glass degraded more than those stored in stainless steel. None of these laboratory results correlated with those obtained from parachutes. Possible explanations for the lack of a correlation are provided in this paper. Additional studies are in progress.

  19. The tensile behavior of demineralized bovine cortical bone.

    PubMed

    Bowman, S M; Zeind, J; Gibson, L J; Hayes, W C; McMahon, T A

    1996-11-01

    Bone is frequently modeled as a two-phase composite of hydroxyapatite mineral crystals dispersed throughout an organic collagen matrix. However, because of the numerous limitations (e.g. small sample size, poor strain measuring techniques, rapid demineralization with acids) of previous mechanical tests of bone with its hydroxyapatite chemically removed, we have determined new, accurate data on the material properties of the demineralized bone matrix for use in these composite models. We performed tensile tests on waisted specimens of demineralized bovine cortical bone from six humeral diaphyses. Specimens were demineralized over 14 days with a 0.5 M disodium EDTA solution that was replaced daily. Atomic absorption spectrophotometry was used to track the demineralization process and to determine the effectiveness of our demineralization protocol. Mechanical tests were performed at room temperature under displacement control at an approximate strain rate of 0.5% per s. We imposed nine preconditioning cycles before a final ramp to failure, and measured gauge length displacements using a non-invasive optical technique. The resulting stress-strain curves were similar to the tensile behavior observed in mechanical tests of other collagenous tissues, exhibiting an initial non-linear 'toe' region, followed by a linear region and subsequent failure without evidence of yielding. We found an average modulus, ultimate stress, and ultimate strain of 613 MPa (S.D. = 113 MPa), 61.5 MPa (S.D. = 13.1 MPa), and 12.3% (S.D. = 0.5%), respectively. Our average modulus is approximately half the value frequently used in current composite bone analyses. These data should also have clinical relevance because the early strength of healing fractured bone depends largely on the material properties of the collagen matrix. PMID:8894931

  20. Tensile Fabrics Enhance Architecture Around the World

    NASA Technical Reports Server (NTRS)

    2009-01-01

    Using a remarkable fabric originally developed to protect Apollo astronauts, Birdair Inc. of Amherst, New York, has crafted highly durable, safe, environmentally friendly, and architecturally stunning tensile membrane roofs for over 900 landmark structures around the world. Travelers in airports, sports fans at stadiums, and shoppers in malls have all experienced the benefits of the Teflon-coated fiberglass fabric that has enabled Birdair to grow from a small company established in its founder?s kitchen in 1955 to a multimillion-dollar specialty contractor today.

  1. Tensile Deformation of Polyethylenes: Crystallinity Effects

    NASA Astrophysics Data System (ADS)

    Crist, Buckley; Metaxas, Costas

    2004-03-01

    The crystalline fraction of polyethylene can be reduced by increasing the cooling rate, the molecular weight or the fraction of comonomer. All three methods have been used in this study of tensile deformation which shows that true stress - true strain behavior depends systematically on morphology. The dependence of uniaxial yield stress on crystal thickness is well understood in terms of dislocation nucleation. Post yield flow is dominated by the strain hardening rate that is larger in polyethylenes of lower crystallinity. Noncrystalline polymer evidently reduces the plastic compliance while providing for elastic (reversible) strains. These observations are examined in terms of old and new theories for deformation of semicrystalline polymers.

  2. Active Tensile Modulus of an Epithelial Monolayer

    NASA Astrophysics Data System (ADS)

    Vincent, Romaric; Bazellières, Elsa; Pérez-González, Carlos; Uroz, Marina; Serra-Picamal, Xavier; Trepat, Xavier

    2015-12-01

    A general trait of cell monolayers is their ability to exert contractile stresses on their surroundings. The scaling laws that link such contractile stresses with the size and geometry of constituent cells remain largely unknown. In this Letter, we show that the active tension of an epithelial monolayer scales linearly with the size of the constituent cells, a surprisingly simple relationship. The slope of this relationship defines an active tensile modulus, which depends on the concentration of myosin and spans more than 2 orders of magnitude across cell types and molecular perturbations.

  3. Stochastic models for the tensile strength, fatigue

    NASA Technical Reports Server (NTRS)

    Phoenix, S. L.

    1976-01-01

    The time-to-failure of a single fiber is modeled as a functional of the fiber load history and reasonable forms for this functional are proposed. Earlier models by Daniels and Coleman are shown to be special cases of the proposed model and apparent disparities in their behavior are discussed. Techniques are presented for determining analytically the asymptotic distributions of the tensile strength and time-to-failure for bundles of a large number of fibers. For smaller bundles, exact results are far too cumbersome to be of use so that efficient Monte Carlo simulation procedures are proposed.

  4. Round robin comparison of tensile results on GlidCop Al25

    SciTech Connect

    Edwards, D.J.; Zinkle, S.J.; Fabritsiev, S.A.; Pokrovsky, A.S.

    1998-09-01

    A round robin comparison of the tensile properties of GlidCop{trademark} Al25 oxide dispersion strengthened copper was initiated between collaborating laboratories to evaluate the test and analysis procedures used in the irradiation experiments in SRIAR in Dimitrovgrad. The tests were conducted using the same tensile specimen geometry as used in previous irradiation experiments, with tests at each laboratory being conducted in air or vacuum at 25, 150, and 300 C at a strain rate of 3 {times} 10{sup {minus}4} s{sup {minus}1}. The strength of the GlidCop Al25 decreased as the test temperature increased, with no observable effect of testing in air versus vacuum on the yield and ultimate strengths. The uniform elongation decreased by almost a factor of 3 when the test temperature was raised from room temperature to 300 C, but the total elongation remained roughly constant over the range of test temperatures. Any effect of testing in air on the ductility may have been masked by the scatter introduced into the results because each laboratory tested the specimens in a different grip setup. In light of this, the results of the round robin tests demonstrated that the test and analysis procedures produced essentially the same values for tensile yield and ultimate, but significant variability was present in both the uniform and total elongation measurements due to the gripping technique.

  5. Collagen network strengthening following cyclic tensile loading.

    PubMed

    Susilo, Monica E; Paten, Jeffrey A; Sander, Edward A; Nguyen, Thao D; Ruberti, Jeffrey W

    2016-02-01

    The bulk mechanical properties of tissues are highly tuned to the physiological loads they experience and reflect the hierarchical structure and mechanical properties of their constituent parts. A thorough understanding of the processes involved in tissue adaptation is required to develop multi-scale computational models of tissue remodelling. While extracellular matrix (ECM) remodelling is partly due to the changing cellular metabolic activity, there may also be mechanically directed changes in ECM nano/microscale organization which lead to mechanical tuning. The thermal and enzymatic stability of collagen, which is the principal load-bearing biopolymer in vertebrates, have been shown to be enhanced by force suggesting that collagen has an active role in ECM mechanical properties. Here, we ask how changes in the mechanical properties of a collagen-based material are reflected by alterations in the micro/nanoscale collagen network following cyclic loading. Surprisingly, we observed significantly higher tensile stiffness and ultimate tensile strength, roughly analogous to the effect of work hardening, in the absence of network realignment and alterations to the fibril area fraction. The data suggest that mechanical loading induces stabilizing changes internal to the fibrils themselves or in the fibril-fibril interactions. If such a cell-independent strengthening effect is operational in vivo, then it would be an important consideration in any multiscale computational approach to ECM growth and remodelling. PMID:26855760

  6. Preparation and tensile properties of linear low density polyethylene/rambutan peels (Nephelium chryseum Blum.) flour blends

    NASA Astrophysics Data System (ADS)

    Nadhirah, A. Ainatun.; Sam, S. T.; Noriman, N. Z.; Voon, C. H.; Samera, S. S.

    2015-05-01

    The effect of rambutan peels flour (RPF) content on the tensile properties of linear low density polyethylene filled with rambutan peel flour was studied. RPF was melt blended with linear low-density polyethylene (LLDPE). LLDPE/RPF blends were prepared by using internal mixer (brabender) at 160 °C with the flour content ranged from 0 to 15 wt%. The tensile properties were tested by using a universal testing machine (UTM) according to ASTM D638. The highest tensile strength was observed for pure LLDPE while the tensile strength LLDPE/RPF decreased gradually with the addition of rambutan peels flour content from 0% to 15%. Young's modulus of 63 µm to 250 µm rambutan peels blends with LLDPE with the fiber loading of 0 - 15 wt% increased with increasing fiber loading.

  7. Biophotonic effect of diode laser irradiance on tensile strength of diabetic rats.

    PubMed

    Lau, Pik Suan; Bidin, Noriah; Krishnan, Ganesan; Nassir, Zaleha; Bahktiar, Hazri

    2015-04-01

    Low-energy laser irradiance at certain wavelengths is able to stimulate the tissue bio-reaction and enhance the healing process. Collagen deposition is one of the important aspects in healing process because it can increase the strength of the skin. This study was designed to examine the biophotonic effect of irradiance on collagen production of diabetic wound in rat model. The tensile strength of skin was employed as a parameter to describe the wound. Diabetic rat models were induced by streptozotocin via intravenous injection. Skin-breaking strength was measured using an Instron tensile test machine. The experimental animals were treated with 808-nm diode laser at two different powers-0.1 and 0.5 W/cm(2)-and 30, 60, and 120 s for each session. The tensile strength was optimized after treated with high-power diode laser. The photostimulation effect was revealed by accelerated healing process and enhanced tensile strength of wound. Laser photostimulation on tensile strength in diabetic wound suggests that such therapy facilitates collagen production in diabetic wound healing. PMID:25260140

  8. Effect of Silver Nano-particles on Tensile Strength of Acrylic Resins

    PubMed Central

    Ghaffari, Tahereh; Hamedi-rad, Fahimeh

    2015-01-01

    Background and aims. Polymethyl methacrylate (PMMA) is widely used for the fabrication of removable prostheses. Silver nano-particles (AgNps) have been added to PMMA because of their antimicrobial properties, but their effect on the mechanical properties of PMMA is unknown. The aim of this study was to investigate the effects of AgNps on the tensile strength of PMMA. Materials and methods. For this study, 12 specimens were prepared and divided into two groups. Group 1 included PMMA without AgNps and group 2 included PMMA mixed with 5 wt% of AgNps. Tensile strength of the specimens was measured by Zwick Z100 apparatus. Statistical analysis was carried out by SPSS using t-test. Statistical significance was defined at P<0.05. Results. This study showed that the mean tensile strength of PMMA in group 2 was significantly lower than that in group 1. Therefore, the tensile strength decreased significantly after incorporation of silver nano-particles. Conclusion. Within the limitations of this study, tensile strength of acrylic resin specimens was influenced by silver nano-particles. PMID:25973153

  9. Effect of particle size and volume fraction on tensile properties of fly ash/polyurea composites

    NASA Astrophysics Data System (ADS)

    Qiao, Jing; Schaaf, Kristin; Amirkhizi, Alireza V.; Nemat-Nasser, Siavouche

    2010-04-01

    Fly ash, which consists of hollow particles with porous shells, was introduced into polyurea elastomer. A one-step method was chosen to fabricate pure polyurea and the polyurea matrix for the composites based on Isonate® 2143L (diisocyanate) and Versalink® P-1000 (diamine). Scanning electron microscopy was used to observe the fracture surfaces of the composites. Particle size and volume fraction were varied to study their effects on the tensile properties of the composites. The tensile properties of the pure polyurea and fly ash/polyurea (FA/PU) composites were tested using an Instron load frame with a 1 kN Interface model 1500ASK-200 load cell. Results showed that fly ash particles were distributed homogeneously in the polyurea matrix, and all of the composites displayed rubber-like tensile behavior similar to that of pure polyurea. The tensile strength of the composites was influenced by both the fly ash size and the volume fraction. Compared to the largest particle size or the highest volume fraction, an increase in tensile strength was achieved by reducing particle size and/or volume fraction. The strain at break of the composites also increased by using fine particles. In addition, the composites filled with 20% fly ash became softer. These samples showed lower plateau strength and larger strain at break than the other composites.

  10. Experimental Study On The Effect Of Micro-Cracks On Brazilian Tensile Strength

    NASA Astrophysics Data System (ADS)

    Wang, Xiangyu

    2015-12-01

    For coal mine ground control issues, it is necessary to propose a failure criteria accounting for the transversely isotropic behaviors of rocks. Hence, it is very helpful to provide experimental data for the validation of the failure criteria. In this paper, the method for preparing transversely isotropic specimens and the scheme of the Brazilian tensile strength test are presented. Results obtained from Brazilian split tests under dry and water-saturated conditions reflect the effect of the development direction β of the structural plane, such as the bedding fissure, on the tensile strength, ultimate displacement, failure mode, and the whole splitting process. The results show that the tensile strength decreases linearly with increasing β. The softening coefficient of the tensile strength shows a sinusoidal function. The values of the slope and inflection point for the curve vary at the different stages of the Brazilian test. The failure mode of the rock specimen presented in this paper generally coincides with the standard Brazilian splitting failure mode. Based on the test results, the major influencing factors for the Brazilian splitting strength are analyzed and a mathematical model for solving the Brazilian splitting strength is proposed. The findings in this paper would greatly benefit the coal mine ground control studies when the surrounding rocks of interest show severe transversely isotropic behaviors.

  11. Lifetime prediction of woven GFRP laminates under constant tensile loading in hydrothermal environment

    NASA Astrophysics Data System (ADS)

    Kotani, Masahiro; Yasufuku, Yusuke; Inoue, Naoki; Kurihara, Ken; Kawada, Hiroyuki

    2013-05-01

    This study aims to investigate the effects of a hydrothermal environment on the creep behavior of woven glass fiber reinforced plastics (GFRPs) and to propose a method for predicting their lifetime. Toward this end, experiments were carried out in air and deionized water at 40, 60, 80 and 95 ∘C. Static tensile tests of woven GFRP were conducted in air and in deionized water to evaluate its mechanical properties and to determine suitable experimental conditions for subsequent constant tensile load tests. The mechanical properties of the woven GFRP decreased with an increase in temperature and with water immersion. Constant tensile load tests were also conducted in air and in deionized water to investigate the creep behavior and fracture time. The fracture time decreased with an increase in stress and water temperature and demonstrated the possibility of a threshold stress for fracturing. In addition, the fracture time during each constant tensile load test was predicted using a modified Reiner-Weissenberg (R-W) criterion, which is a failure criterion for linear viscoelastic materials based on the accumulation of dissolved energy within the GFRP. In this study, the R-W criterion was modified to consider the effects of degradation and its acceleration, which are due to the applied stress and immersion in a solution. The predicted results were in good agreement with the experimental data when considering the effects of hydrothermal aging.

  12. Elevated-temperature tensile and creep properties of several ferritic stainless steels

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1977-01-01

    The elevated-temperature mechanical properties of several ferritic stainless steels were determined. The alloys evaluated included Armco 18SR, GE 1541, and NASA-18T-A. Tensile and creep strength properties at 1073 and 1273 K and residual room temperature tensile properties after creep testing were measured. In addition, 1273 K tensile and creep tests and residual property testing were conducted with Armco 18SR and GE 1541 which were exposed for 200 hours to a severe oxidizing environment in automotive thermal reactors. Aside from the residual tensile properties for Armco 18SR, prior exposure did not affect the mechanical properties of either alloy. The 1273 K creep strength parallel to the sheet-rolling direction was similar for all three alloys. At 1073 K, NASA-18T-A had better creep strength than either Armco 18SR or GE 1541. NASA-18T-A possesses better residual properties after creep testing than either Armco 18SR or Ge 1541.

  13. Tensile and charpy impact properties of irradiated reduced-activation ferritic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1996-10-01

    Tensile tests were conducted on eight reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on the steels irradiated to 26-29 dpa. Irradiation was in the Fast Flux Test Facility at 365{degrees}C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15-17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20000 h at 365{degrees}C. Thermal aging had little effect on the tensile behavior or the ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in the upper-shelf energy (USE). After {approx}7 dpa, the strength of the steels increased and then remained relatively unchanged through 26-29 dpa (i.e., the strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness, as measured by an increase in DBTT and a decrease in the USE, remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels were the most irradiation resistant.

  14. DEVELOPMENT OF TENSILE STRENGTH DURING DISTRACTION OSTEOGENESIS IN A RAT MODEL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    These studies were designed to determine the reliability of in vitro tensile testing to measure the temporal development of regenerate bone strength in rats during limb lengthening (distraction osteogenesis, DO). External fixators were placed on the right tibiae of 36 virus-free, 400-450 g male Spr...

  15. Tensile and creep rupture properties of (16) uncoated and (2) coated engineering alloys at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Fritz, L. J.; Koster, W. P.

    1977-01-01

    Sixteen test materials were supplied by NASA-Lewis Research Center as wrought bar or cast remelt stock. The cast remelt stock was cast into test blanks with two such materials being also evaluated after Jocoat coating was applied. Mechanical properties evaluated included tensile, modulus of elasticity, Poisson's Ratio, creep properties and creep rupture strength. Tests were conducted at temperatures applicable to the service temperature of the various alloys. This range extended from room temperature to 1000 C.

  16. DYNAMIC RESPONSE OF IMMATURE BOVINE ARTICULAR CARTILAGE IN TENSION AND COMPRESSION, AND NONLINEAR VISCOELASTIC MODELING OF THE TENSILE RESPONSE

    PubMed Central

    Park, Seonghun; Ateshian, Gerard A.

    2010-01-01

    Objectives Very limited information is currently available on the constitutive modeling of the tensile response of articular cartilage and its dynamic modulus at various loading frequencies. The objectives of this study were to 1) formulate and experimentally validate a constitutive model for the intrinsic viscoelasticity of cartilage in tension, 2) confirm the hypothesis that energy dissipation in tension is less than in compression at various loading frequencies, and 3) test the hypothesis that the dynamic modulus of cartilage in unconfined compression is dependent upon the dynamic tensile modulus. Methods Experiment 1: Immature bovine articular cartilage samples were tested in tensile stress relaxation and cyclical loading. A proposed reduced relaxation function was fitted to the stress-relaxation response and the resulting material coefficients were used to predict the response to cyclical loading. Adjoining tissue samples were tested in unconfined compression stress relaxation and cyclical loading. Experiment 2: Tensile stress relaxation experiments were performed at varying strains to explore the strain-dependence of the viscoelastic response. Results The proposed relaxation function successfully fit the experimental tensile stress-relaxation response, with R2 =0.970±0.019 at 1 % strain and R2 =0.992±0.007 at 2 % strain. The predicted cyclical response agreed well with experimental measurements, particularly for the dynamic modulus at various frequencies. The relaxation function, measured from 2% to 10% strain, was found to be strain-dependent, indicating that cartilage is nonlinearly viscoelastic in tension. Under dynamic loading, the tensile modulus at 10 Hz was ~2.3 times the value of the equilibrium modulus. In contrast, the dynamic stiffening ratio in unconfined compression was ~24. The energy dissipation in tension was found to be significantly smaller than in compression (dynamic phase angle of 16.2±7.4° versus 53.5±12.8° at 10−3 Hz). A very

  17. Effects of Plasma Nitriding on the Tensile Properties of Al-Mg-Si

    NASA Astrophysics Data System (ADS)

    Ghauri, I. M.; Ahmad, R.; Mubarik, F. E.; Afzal, Naveed; Ahmed, Sajjad; Ayub, R.

    2012-07-01

    Effects of plasma nitriding on the tensile behavior of Al-Mg-Si alloy were investigated in this study. The specimens were nitrided at 70 W input pulsed DC power at 1 mbar pressure of nitrogen for 4 h using glow discharge plasma. The formation of aluminum nitride layer on the specimen's surface was confirmed by the XRD analysis. Stress-strain curves of both un-nitrided and nitrided specimens were obtained using Universal Testing Machine. The comparison of these curves reveals that yield stress, ultimate tensile stress, percentage elongation, and stress relaxation rate decrease after plasma nitriding. The changes in the tensile properties after nitriding have been correlated with the changes in the microstructure of the specimens as observed using scanning electron microscope.

  18. Tensile behavior of unnotched and notched tungsten-copper laminar composites

    NASA Technical Reports Server (NTRS)

    Hoffman, C. A.

    1976-01-01

    Relations were studied between the tensile strengths of unnotched and of notched, and elastic moduli of unnotched laminar sheet or foil composites and the amounts of reinforcement. Tungsten was used as the reinforcement and copper as the matrix, and the tests were run at room temperature. Three thicknesses of tungsten (i.e., 0.00254, 0.0127, and 0.0254 cm (0.001, 0.005, and 0.010 in) were used and the nominal volume fraction of tungsten was varied from about 0.05 to 0.95. It was found that the tensile strength of the unnotched specimens could be related to the amount of reinforcement, as could the elastic moduli, and that these values could be predicted by use of the rule of mixtures. The tensile strengths of the notched laminar composites could be predicted by use of the rule of mixtures using strengths for notched constituents, provided notch effects did not predominate.

  19. Investigation on the tensile behavior of fiber metal laminates based on self-reinforced polypropylene

    NASA Astrophysics Data System (ADS)

    Lee, Byoung-Eon; Park, Tom; Kim, Jeong; Kang, Beom-Soo; Song, Woo-Jin

    2013-12-01

    Mechanical tests have been carried out to accurately evaluate the tensile properties of fiber metal laminates (FMLs). The FMLs in this paper comprised of a layer of self-reinforced polypropylene (SRPP) sandwiched between two layers of aluminum alloy 5052-H34. In this study, nonlinear tensile and fracture behavior of FMLs under the in-plane loading conditions has been investigated with numerical simulations and theoretical analysis. The numerical simulation based on finite element modeling using the ABAQUS/Explicit and the theoretical constitutive model based on a volume fraction approach and a modified classical lamination theory, which incorporates the elastic-plastic behavior of the aluminum alloy are used to predict the mechanical properties such as stress-strain response and deformation behavior of FMLs. In addition, through comparing the numerical simulations and the theoretical analysis with experimental results, it was concluded that a numerical simulation model adopted describes with sufficient accuracy the overall tensile stress-strain curve.

  20. Cryogenic Tensile Strength and Fatigue Life of Carbon Nanotube Multi-Yarn.

    PubMed

    Misak, H E; Mall, S

    2016-03-01

    Carbon nanotube (CNT) multi-yarns, consisting of 30 yarns, were tested under monotonic tensile load and fatigue at the room temperature (298 K) and two cryogenic temperatures (232 and 123 K). Tensile stiffness increased with the decrease of temperature. The average ultimate tensile strength was higher at 123 K when compared to the higher temperatures (232 and 298 K). Failure mechanism changed from a combination of classical variant and independent fiber breakage at the two higher temperatures to mostly classical variant failure mechanism at the lower temperature. The CNT-yarn's fatigue life also increased with decreasing temperature. CNT-yarns have been shown to function well at lower temperatures making them usable for applications requiring operation at cryogenic temperatures, such as in satellites and high altitude aircraft. PMID:27455753

  1. Tensile and Impact Properties of Thermoplastic Natural Rubber (TPNR) Filled with Carbon Nanotubes (MWNTs)

    NASA Astrophysics Data System (ADS)

    Tarawneh, Mou'ad. A.; Ahmad, Sahrim Hj.; Yahya, S. Y.; Rasid, Rozaidi; Hock, Yew Chin; Halim, Hazwani Binti

    2010-07-01

    This paper discusses the effect of multi-walled carbon nanotubes (MWNT) on the tensile and impact properties of thermoplastic natural rubber (TPNR) nanocomposite. The nanocomposite was prepared using melt blending method. MWNT were added to improve the mechanical properties of MWNTs/TPNR composites at different compositions which is 1, 3, 5, and 7 wt.%. The result of tensile test showed that tensile strength and Young's modulus increase in the presence of nanotubes and maximum value are obtained with 3 wt.% of MWNTs. On other hand, higher MWNTs concentration has caused the formation of aggregates. The elongation at break considerably decreased with increasing the percentage of MWNTs. The maximum impact strength is recorded with 5 wt.% of MWNTs. SEM micrograph has confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which is improved mechanical significantly.

  2. The Tensile Properties of Advanced Nickel-Base Disk Superalloys During Quenching Heat Treatments

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Kantzos, Pete T.; Biles, Tiffany; Konkel, William

    2001-01-01

    There is a need to increase the temperature capabilities of superalloy turbine disks. This would allow full utilization of higher temperature combustor and airfoil concepts under development. One approach to meet this goal is to modify the processing and chemistry of advanced alloys, while preserving the ability to use rapid cooling supersolvus heat treatments to achieve coarse grain, fine gamma prime microstructures. An important step in this effort is to understand the key high temperature tensile properties of advanced alloys as they exist during supersolvus heat treatments. This could help in projecting cracking tendencies of disks during quenches from supersolvus heat treatments. The objective of this study was to examine the tensile properties of two advanced disk superalloys during simulated quenching heat treatments. Specimens were cooled from the solution heat treatment temperatures at controlled rates, interrupted, and immediately tensile tested at various temperatures. The responses and failure modes were compared and related to the quench cracking tendencies of disk forgings.

  3. Tensile properties of an ultrahigh-strength graphite fiber in an epoxy matrix

    NASA Technical Reports Server (NTRS)

    Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.

    1974-01-01

    The fiber performance and reinforcement potential for fiber composites of a special PAN-based graphite fiber were evaluated by testing the fiber's tensile properties in an epoxy matrix. Representative strand samples were taken from 30 spools of single-end, 1500-filament fiber to make over 5000 fiber/epoxy strand specimens using the filament-winding process. Characteristics studied were fiber uniformity, strength and modulus distributions at room and liquid-nitrogen temperatures, stress-strain behavior, the effect of strain rate on fiber strength, and acoustic emission during tensile loading to failure. The fiber was found to have a 3570-MPa failure stress, a 1.7% failure strain, a 206-GPa modulus, and a density of 1.77 Mg/cu m at 23 C. Liquid-nitrogen temperature and various strain rates had no significant effect on fiber tensile properties.

  4. A comparison of tensile properties of polyester composites reinforced with pineapple leaf fiber and pineapple peduncle fiber

    NASA Astrophysics Data System (ADS)

    Juraidi, J. M.; Shuhairul, N.; Syed Azuan, S. A.; Intan Saffinaz Anuar, Noor

    2013-12-01

    Pineapple fiber which is rich in cellulose, relatively inexpensive, and abundantly available has the potential for polymer reinforcement. This research presents a study of the tensile properties of pineapple leaf fiber and pineapple peduncle fiber reinforced polyester composites. Composites were fabricated using leaf fiber and peduncle fiber with varying fiber length and fiber loading. Both fibers were mixed with polyester composites the various fiber volume fractions of 4, 8 and 12% and with three different fiber lengths of 10, 20 and 30 mm. The composites panels were fabricated using hand lay-out technique. The tensile test was carried out in accordance to ASTM D638. The result showed that pineapple peduncle fiber with 4% fiber volume fraction and fiber length of 30 mm give highest tensile properties. From the overall results, pineapple peduncle fiber shown the higher tensile properties compared to pineapple leaf fiber. It is found that by increasing the fiber volume fraction the tensile properties has significantly decreased but by increasing the fiber length, the tensile properties will be increased proportionally. Minitab software is used to perform the two-way ANOVA analysis to measure the significant. From the analysis done, there is a significant effect of fiber volume fraction and fiber length on the tensile properties.

  5. Tensile and compressive test results for metal matrix composites

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    Experimental results of the mechanical behavior of two metal matrix composite systems at room temperature are presented. Ultimate stress, ultimate strain, Poisson's ratio, and initial Young's Modulus are documented for BORSIC/Aluminum in uniaxial tension and Boron/Aluminum in uniaxial tension and compression. Poisson's ratio is used for nonlinear stress-strain behavior. A comparison of compression results for B/Al as obtained from sandwich beam compression specimens and IITRI coupon compression specimens is presented.

  6. Preparation and tensile properties of DD5 single crystal castings

    NASA Astrophysics Data System (ADS)

    Liang, Xiang-feng; Zhao, Yu-tao; Jia, Zhi-hong; Zhang, Chi

    2016-06-01

    The preparation procedure of DD5 single crystal castings was optimized. The microstructure characteristics of DD5 single crystal superalloy were investigated by microstructure observation and segregation behavior examination. The results show that the grain orientation is optimized by constraining the spiral crystallizer in [001] orientation and spatial scale. Also, the γ' phase of inter-dendrites is larger and more irregular than that in dendrite arms. High temperature tensile tests of DD5 single crystal castings exhibit that the peak stress increases with increasing temperature, while the area reduction shows an opposite trend, when the temperature is below 800°C; meanwhile, when the temperature is between 800°C and 1000°C, the fracture stress of the alloy is the same as the peak stress. The fracture mode changes from shear to ductile with increasing temperature from 600°C and 1000°C.

  7. Prediction of residual tensile strength of transversely impacted composite laminates

    NASA Technical Reports Server (NTRS)

    Lal, K. M.

    1982-01-01

    The response to low velocity impact of graphite-epoxy T300/5208 composite laminates is discussed. Steel balls of 3/8 inch, 5/8 inch, and 1 inch diameter were the projectiles. Impact energy was limited to 1.2 joules. Impacted specimens were ultrasonically C scanned to determine the impact damaged region. The threshold value of impact energy for impact damage was found to be approximately 0.3 joules. A model was developed to predict the tensile residual strength of impact damaged specimens from fracture mechanics concepts. Impacted specimens were tested in tension to provide a fracture data base. The experimental results agreed well with the predictions from fracture mechanics. In this study, the maximum impact velocity used to simulate the low velocity transverse impact from common objects like tool drops was 10 m/s.

  8. Tensile stress-strain behavior of graphite/epoxy laminates

    NASA Technical Reports Server (NTRS)

    Garber, D. P.

    1982-01-01

    The tensile stress-strain behavior of a variety of graphite/epoxy laminates was examined. Longitudinal and transverse specimens from eleven different layups were monotonically loaded in tension to failure. Ultimate strength, ultimate strain, and strss-strain curves wee obtained from four replicate tests in each case. Polynominal equations were fitted by the method of least squares to the stress-strain data to determine average curves. Values of Young's modulus and Poisson's ratio, derived from polynomial coefficients, were compared with laminate analysis results. While the polynomials appeared to accurately fit the stress-strain data in most cases, the use of polynomial coefficients to calculate elastic moduli appeared to be of questionable value in cases involving sharp changes in the slope of the stress-strain data or extensive scatter.

  9. Tensile and Creep-Rupture Evaluation of a New Heat of Haynes Alloy 25

    SciTech Connect

    Shingledecker, J.P.; Glanton, D.B.; Martin, R.L.; Sparks, B.L.; Swindeman, R.W.

    2007-02-14

    From 1999 to 2006, a program was undertaken within the Materials Science and Technology Division, formerly the Metals and Ceramics Division, of Oak Ridge National Laboratory to characterize the tensile and creep-rupture properties of a newly produced heat of Haynes alloy 25 (L-605). Tensile properties from room temperature to 1100 C were evaluated for base material and welded joints aged up to 12,000 hours at 675 C. Creep and creep-rupture tests were conducted on base metal and cross-weldments from 650 to 950 C. Pressurized tubular creep tests were conducted to evaluate multiaxial creep-rupture response of the material. Over 800,000 hours of creep test data were generated during the test program with the longest rupture tests extending beyond 38,000 hours, and the longest creep-rate experiments exceeding 40,000 hours.

  10. Tensile-property characterization of thermally aged cast stainless steels.

    SciTech Connect

    Michaud, W. F.; Toben, P. T.; Soppet, W. K.; Chopra, O. K.; Energy Technology

    1994-03-03

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  11. Tensile-property characterization of thermally aged cast stainless steels

    SciTech Connect

    Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K.

    1994-02-01

    The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components.

  12. Modelling and Simulation of Tensile Fracture in High Velocity Compacted Metal Powder

    SciTech Connect

    Jonsen, P.; Haeggblad, H.-A.

    2007-05-17

    In cold uniaxial powder compaction, powder is formed into a desired shape with rigid tools and a die. After pressing, but before sintering, the compacted powder is called green body. A critical property in the metal powder pressing process is the mechanical properties of the green body. Beyond a green body free from defects, desired properties are high strength and uniform density. High velocity compaction (HVC) using a hydraulic operated hammer is a production method to form powder utilizing a shock wave. Pre-alloyed water atomised iron powder has been HVC-formed into circular discs with high densities. The diametral compression test also called the Brazilian disc test is an established method to measure tensile strength in low strength material like e.g. rock, concrete, polymers and ceramics. During the test a thin disc is compressed across the diameter to failure. The compression induces a tensile stress perpendicular to the compressed diameter. In this study the test have been used to study crack initiation and the tensile fracture process of HVC-formed metal powder discs with a relative density of 99%. A fictitious crack model controlled by a stress versus crack-width relationship is utilized to model green body cracking. Tensile strength is used as a failure condition and limits the stress in the fracture interface. The softening rate of the model is obtained from the corresponding rate of the dissipated energy. The deformation of the powder material is modelled with an elastic-plastic Cap model. The characteristics of the tensile fracture development of the central crack in a diametrically loaded specimen is numerically studied with a three dimensional finite element simulation. Results from the finite element simulation of the diametral compression test shows that it is possible to simulate fracturing of HVC-formed powder. Results from the simulation agree reasonably with experiments.

  13. Modelling and Simulation of Tensile Fracture in High Velocity Compacted Metal Powder

    NASA Astrophysics Data System (ADS)

    Jonsén, P.; Häggblad, H.-A.˚.

    2007-05-01

    In cold uniaxial powder compaction, powder is formed into a desired shape with rigid tools and a die. After pressing, but before sintering, the compacted powder is called green body. A critical property in the metal powder pressing process is the mechanical properties of the green body. Beyond a green body free from defects, desired properties are high strength and uniform density. High velocity compaction (HVC) using a hydraulic operated hammer is a production method to form powder utilizing a shock wave. Pre-alloyed water atomised iron powder has been HVC-formed into circular discs with high densities. The diametral compression test also called the Brazilian disc test is an established method to measure tensile strength in low strength material like e.g. rock, concrete, polymers and ceramics. During the test a thin disc is compressed across the diameter to failure. The compression induces a tensile stress perpendicular to the compressed diameter. In this study the test have been used to study crack initiation and the tensile fracture process of HVC-formed metal powder discs with a relative density of 99%. A fictitious crack model controlled by a stress versus crack-width relationship is utilized to model green body cracking. Tensile strength is used as a failure condition and limits the stress in the fracture interface. The softening rate of the model is obtained from the corresponding rate of the dissipated energy. The deformation of the powder material is modelled with an elastic-plastic Cap model. The characteristics of the tensile fracture development of the central crack in a diametrically loaded specimen is numerically studied with a three dimensional finite element simulation. Results from the finite element simulation of the diametral compression test shows that it is possible to simulate fracturing of HVC-formed powder. Results from the simulation agree reasonably with experiments.

  14. Tensile Mechanical Properties of Swine Cortical Mandibular Bone

    PubMed Central

    Brosh, Tamar; Rozitsky, Doron; Geron, Silvia; Pilo, Raphael

    2014-01-01

    Temporary orthodontic mini implants serve as anchorage devices in orthodontic treatments. Often, they are inserted in the jaw bones, between the roots of the teeth. The stability of the mini implants within the bone is one of the major factors affecting their success and, consequently, that of the orthodontic treatment. Bone mechanical properties are important for implant stability. The aim of this study was to determine the tensile properties of the alveolar and basal mandible bones in a swine model. The diametral compression test was employed to study the properties in two orthogonal directions: mesio-distal and occluso-gingival. Small cylindrical cortical bone specimens (2.6 mm diameter, 1.5 mm thickness) were obtained from 7 mandibles using a trephine drill. The sites included different locations (anterior and posterior) and aspects (buccal and lingual) for a total of 16 specimens from each mandible. The load-displacement curves were continuously monitored while loading half of the specimens in the oclluso-gingival direction and half in the mesio-distal direction. The stiffness was calculated from the linear portion of the curve. The mesio-distal direction was 31% stiffer than the occluso-gingival direction. The basal bone was 40% stiffer than the alveolar bone. The posterior zone was 46% stiffer than the anterior zone. The lingual aspect was stiffer than the buccal aspect. Although bone specimens do not behave as brittle materials, the diametral compression test can be adequately used for determining tensile behavior when only small bone specimens can be obtained. In conclusion, to obtain maximal orthodontic mini implant stability, the force components on the implants should be oriented mostly in the mesio-distal direction. PMID:25463971

  15. Importance of Tensile Strength on the Shear Behavior of Discontinuities

    NASA Astrophysics Data System (ADS)

    Ghazvinian, A. H.; Azinfar, M. J.; Geranmayeh Vaneghi, R.

    2012-05-01

    In this study, the shear behavior of discontinuities possessing two different rock wall types with distinct separate compressive strengths was investigated. The designed profiles consisted of regular artificial joints molded by five types of plaster mortars, each representing a distinct uniaxial compressive strength. The compressive strengths of plaster specimens ranged from 5.9 to 19.5 MPa. These specimens were molded considering a regular triangular asperity profile and were designed so as to achieve joint walls with different strength material combinations. The results showed that the shear behavior of discontinuities possessing different joint wall compressive strengths (DDJCS) tested under constant normal load (CNL) conditions is the same as those possessing identical joint wall strengths, but the shear strength of DDJCS is governed by minor joint wall compressive strength. In addition, it was measured that the predicted values obtained by Barton's empirical criterion are greater than the experimental results. The finding indicates that there is a correlation between the joint roughness coefficient (JRC), normal stress, and mechanical strength. It was observed that the mode of failure of asperities is either pure tensile, pure shear, or a combination of both. Therefore, Barton's strength criterion, which considers the compressive strength of joint walls, was modified by substituting the compressive strength with the tensile strength. The validity of the modified criterion was examined by the comparison of the predicted shear values with the laboratory shear test results reported by Grasselli (Ph.D. thesis n.2404, Civil Engineering Department, EPFL, Lausanne, Switzerland, 2001). These comparisons infer that the modified criterion can predict the shear strength of joints more precisely.

  16. Influence of thermo-mechanical treatment on the tensile properties of a modified 14Cr-15Ni stainless steel

    NASA Astrophysics Data System (ADS)

    Vijayanand, V. D.; Laha, K.; Parameswaran, P.; Nandagopal, M.; Panneer Selvi, S.; Mathew, M. D.

    2014-10-01

    The titanium modified 14Cr-15Ni austenitic stainless steel is used as clad and wrapper material for fast breeder nuclear reactor. Thermo-mechanical treatments consisting of solution annealing at two different temperatures of 1273 and 1373 K followed by cold-work and thermal ageing have been imparted to the steel to tailor its microstructure for enhancing strength. Tensile tests have been carried out on the thermo-mechanically treated steel at nominal strain rate of 1.6 × 10-4 s-1 over a temperature range of 298-1073 K. The yield stress and the ultimate tensile strength of the steel increased with increase in solution treatment temperature and this has been attributed to the fine and higher density of Ti(C,N) precipitate. Tensile flow behaviour of the steel has been analysed using Ludwigson and Voce constitutive equations. The steel heat treated at higher solution temperature exhibited earlier onset of cross slip during tensile deformation. The rate of recovery at higher test temperatures was also influenced by variations in solution heat treatment temperature. In addition, dynamic recrystallization during tensile deformation at higher temperatures was profound for steel solution heat-treated at lower temperature. The differences in flow behaviour and softening mechanisms during tensile testing of the steel after different heat treated conditions have been attributed to the nature of Ti(C,N) precipitation.

  17. An Evaluation Method for Tensile Characteristics of Cu/Sn IMCs Using Miniature Composite Solder Specimen

    NASA Astrophysics Data System (ADS)

    Ohguchi, Ken-ichi; Kurosawa, Kengo

    2016-06-01

    In design of electronic packages, finite-element method (FEM) analysis for evaluating the strength and reliability of solder joints should be conducted with consideration of the presence of Cu/Sn intermetallic compounds (IMCs) generated at the interface between solder and copper wiring. To conduct such analysis accurately, the deformation characteristics of Cu/Sn IMCs must be clarified by conducting tensile tests. This paper describes a method to evaluate tensile characteristics of Cu/Sn IMCs. The method employs a composite specimen with first outer layer of Cu, second layer of Cu/Sn IMCs, and core of Sn-3.0Ag-0.5Cu lead-free solder. The specimen is made by a method in which a copper-plated solder specimen is heat treated at 453 K to generate Cu/Sn IMCs between the solder and copper. Tensile tests were conducted using the composite specimen. After the tests, the fracture appearance and characteristics of the stress-strain relations of the specimens were investigated. Based on the results, a numerical method based on the rule of mixtures (ROM) is proposed to estimate the stress-strain relation of Cu/Sn IMCs under tensile loading.

  18. Twinning and martensitic transformations in nickel-enriched 304 austenitic steel during tensile and indentation deformations

    SciTech Connect

    Gussev, Maxim N; Busby, Jeremy T; Byun, Thak Sang; Parish, Chad M

    2013-01-01

    Twinning and martensitic transformation have been investigated in nickel-enriched AISI 304 stainless steel subjected to tensile and indentation deformation. Using electron backscatter diffraction (EBSD), the morphology of alpha- and epsilon-martensite and the effect of grain orientation to load axis on phase and structure transformations were analyzed in detail. It was found that the twinning occurred less frequently under indentation than under tension; also, twinning was not observed in [001] and [101] grains. In tensile tests, the martensite particles preferably formed at the deformation twins, intersections between twins, or at twin-grain boundary intersections. Conversely, martensite formation in the indentation tests was not closely associated with twinning; instead, the majority of martensite was concentrated in the dense colonies near grain boundaries. Martensitic transformation seemed to be obstructed in the [001] grains in both tensile and indentation test cases. Under a tensile stress of 800 MPa, both alpha- and epsilon-martensite were found in the microstructure, but at 1100 MPa only -martensite presented in the specimen. Under indentation, alpha- and epsilon-martensite were observed in the material regardless of stress level.

  19. Tensile strength of fiber reinforced plastics at 77K irradiated by various radiation sources

    SciTech Connect

    Humer, K.; Weber, H.W.; Tschegg, E.K.; Egusa, S.; Birtcher, R.C.; Gerstenberg, H.

    1993-08-01

    The influence of radiation damage on the mechanical properties of fiber reinforced plastics (FRPs), which are considered as candidate materials for the insulation of superconducting magnets for nuclear fusion reactors, has been investigated. Different types of FRPs (epoxies, bismaleimides; two- and three-dimensional reinforcement structures with E-, S-, or T-glass fibers) has been included in the test program. Three aspects of our present results will be discussed in detail. The first is related to an assessment of the tensile strength and its radiation dependence under the influence of strongly varying radiation conditions. The second aspect refers to low temperature ({approx}5 K) reactor irradiation of selected materials. In this case, identical sets of tensile test samples were transferred into the tensile testing machine, one without warming-up to room temperature and the other after an annealing cycle to room temperature. Finally, a comparison between the radiation response of different materials is made. It turns out that the three-dimensionally reinforced bismaleimide shows the smallest degradation of its tensile properties under all irradiation conditions.

  20. An Evaluation Method for Tensile Characteristics of Cu/Sn IMCs Using Miniature Composite Solder Specimen

    NASA Astrophysics Data System (ADS)

    Ohguchi, Ken-ichi; Kurosawa, Kengo

    2016-03-01

    In design of electronic packages, finite-element method (FEM) analysis for evaluating the strength and reliability of solder joints should be conducted with consideration of the presence of Cu/Sn intermetallic compounds (IMCs) generated at the interface between solder and copper wiring. To conduct such analysis accurately, the deformation characteristics of Cu/Sn IMCs must be clarified by conducting tensile tests. This paper describes a method to evaluate tensile characteristics of Cu/Sn IMCs. The method employs a composite specimen with first outer layer of Cu, second layer of Cu/Sn IMCs, and core of Sn-3.0Ag-0.5Cu lead-free solder. The specimen is made by a method in which a copper-plated solder specimen is heat treated at 453 K to generate Cu/Sn IMCs between the solder and copper. Tensile tests were conducted using the composite specimen. After the tests, the fracture appearance and characteristics of the stress-strain relations of the specimens were investigated. Based on the results, a numerical method based on the rule of mixtures (ROM) is proposed to estimate the stress-strain relation of Cu/Sn IMCs under tensile loading.