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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. Evaluation of nondestructive tensile testing

    NASA Technical Reports Server (NTRS)

    Bowe, J. J.; Polcari, S. M.

    1971-01-01

    The results of a series of experiments performed in the evaluation of nondestructive tensile testing of chip and wire bonds are presented. Semiconductor devices were subjected to time-temperature excursions, static-load life testing and multiple pre-stressing loads to determine the feasibility of a nondestructive tensile testing approach. The report emphasizes the importance of the breaking angle in determining the ultimate tensile strength of a wire bond, a factor not generally recognized nor implemented in such determinations.

  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 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.

  8. 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.

  9. Uniaxial Tensile Test for Soil.

    DTIC Science & Technology

    1987-04-01

    by radiographs to be uniform. 8. Direct tensile triaxial tests performed by Conlon (1966), Bishop and Garga (1969), and Parry and Nadarajah (1974...Parry, R. H. G., and Nadarajah , V. 1974. "Anisotrophy in a Natural Soft Clayey Silt," Engineering Geology, Vol 8, No. 3, pp 287-309. 47 .• ’°"I Peters

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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).

  17. BIAXIAL TENSILE TESTS OF COATED FABRICS

    DTIC Science & Technology

    This report discusses the design, operation, and purpose of a new biaxial tensile test instrument to measure the stress-strain behavior of fabrics...comparison is made between these data and previous work performed with other tensile test equipment.

  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. 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.

  20. Synthetic Mooring Line Tensile Testing Procedure.

    DTIC Science & Technology

    1975-09-01

    tensile test procedure is necessary that will provide commonality among tensile tests of synthetic lines of all materials, diameters and lengths. A relationship was derived that relates material stiffness, diameter, and sample lengths to the strain rate during a tensile test . A first order experiment was conducted in which synthetic lines were tensile tested at various strain rates to determine to what degree tensile strength is affected by strain rate. Results show that the dispersion among individual data points overshadows the general trend of any

  1. Dynamic Tensile Test Results for Several Metals

    DTIC Science & Technology

    1982-04-01

    8217• AFWAL-TR-82-4026 SDYNAMIC TENSILE TEST RESULTS FOR SEVERAL METALS SUNIVERSITY OF DAYTON RESEA CH INSTITUTE ’ 300 COLLEGE PARK DR. DAYTON, OHIO... Tensile Test Results for March - September 1981 Several Metals 6. PERFORMING oDG. REPORT NUMBER UDR-TR-82-05 7. AUTHOR(s) S. CONTRACT OfR GRANT NUMBER(&) S...tensile stresses above 10 s The split Hopkinson bar tensile test (see next section) can extend this range another decade. Resolution of rapidly

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Temperature controlled tensile testing of individual nanowires.

    PubMed

    Chen, Lisa Y; Terrab, Soraya; Murphy, Kathryn F; Sullivan, John P; Cheng, Xuemei; Gianola, Daniel S

    2014-01-01

    We present a novel experimental method for quantitatively characterizing the temperature-dependent mechanical behavior of individual nanostructures during uniaxial straining. By combining a microelectromechanical tensile testing device with a low thermal mass and digital image correlation providing nm-level displacement resolution, we show successful incorporation of a testing platform in a vacuum cryostat system with an integrated heater and temperature control. Characterization of the local sample temperature and time-dependent response at both low and high temperature demonstrates a testing range of ∼90-475 K and steady-state drift rates less than 0.04 K/min. In situ operation of the tensile testing device employing resistively heated thermal actuators while imaging with an optical microscope enables high-resolution displacement measurements, from which stress-strain behavior of the nanoscale specimens is deduced. We demonstrate the efficacy of our approach in measuring the temperature dependence of tensile strength in nominally defect-free ⟨110⟩ Pd nanowhiskers. We uncover a pronounced sensitivity of the plastic response to testing temperature over a range of ∼300 K, with an ultimate strength in excess of 6 GPa at low temperature. The results are discussed in the context of thermally activated deformation mechanisms and defect nucleation in defect-free metallic nanostructures.

  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. 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

  11. High-speed tensile test instrument.

    PubMed

    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.

  12. 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.

  13. NGNP Engineering Status

    SciTech Connect

    John Collins

    2010-08-01

    The objectives of Phase 1 Engineering and Design scope are to: 1) complete the initial design activities for a prototype nuclear reactor and plant that is capable of co-generating electricity, hydrogen, and process heat; 2) identify technological aspects of the NGNP that need further advancement by research and development activities; and 3) provide engineering support to the early licensing process, including technical input to white papers and developing the basis for future safety analyses.

  14. Tensile and Compressive Tests of Magnesium Alloy J-1 Sheet

    DTIC Science & Technology

    1943-12-01

    Tensile and compressive properties of longitudinal and transverse specimens of magnesium alloy J-1 sheets, 0.032 and 0.12 in. thick, were tested. It was found that he tensile properties were above the Navy specification 47M2a for magnesium-base-alloy 8H. Longitudinal and transverse specimens were in close agreement in the tensile test . In the compressive yield strengths, longitudinal direction was much less

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Testing Tensile and Shear Epoxy Strength at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Alberts, S. J.; Doehne, C. J.; Johnson, W. L.

    2017-01-01

    This paper covers cryogenic, tensile testing and research completed on a number of epoxies used in cryogenic applications. Epoxies are used in many different applications; however, this research focused on the use of epoxy used to bond MLI standoffs to cryogenic storage tanks and the loads imparted to the tank through the MLI. To conduct testing, samples were made from bare stainless steel, aluminum and primed aluminum. Testing involved slowly cooling test samples with liquid nitrogen then applying gradually increasing tensile loads to the epoxy. The testing evaluated the strength and durability of epoxies at cryogenic temperatures and serves as a base for future testing. The results of the tests showed that some epoxies withstood the harsh conditions while others failed. The two epoxies yielding the best results were Masterbond EP29LPSP and Scotch Weld 2216. For all metal surfaces tested, both epoxies had zero failures for up to 11.81 kg of mass.

  4. 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.

  5. Tensile test of dumbbell-shaped specimen in thickness direction

    NASA Astrophysics Data System (ADS)

    Iizuka, Takashi

    2016-10-01

    Sheet metal forming is widely used in manufacturing shops, and evaluation of forming limit for sheet metal is important. However, specimen shape influences on the fracture of the sheet metal. As one of methods to decrease these effects, an uniaxial tensile test using specimen dumbbell-shaped in thickness direction had been examined using FEM analysis. In this study, actually specimen dumbbell-shaped in thickness direction was fabricated using a new incremental sheet forging method, and uniaxial tensile test was conducted. Load-stroke diagram, fracture morphologies, stress-strain curves and shape after fracture were investigated, and effects of specimen shape were considered. Elongation was larger as using specimen dumbbell-shaped in the width direction. Stress-strain curves until necking occurred were less influenced by specimen shape. However, yield stress decreased and local elongation increased as using specimen dumbbell-shaped in the width direction. The reasons why these tendencies showed were considered in the view of specimen shapes.

  6. 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.

  7. 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.

  8. Gage for Measuring Decrease in Dimension of Test Specimen in Tensile Test.

    DTIC Science & Technology

    respect to the frame member and provides an output signal proportional to displacement. Elastic bands are used to support the test gage on a tensile test machine which is used to apply a stress to the test specimen. (Author)

  9. Biaxial tensile testing and constitutive modeling of human supraspinatus tendon.

    PubMed

    Szczesny, Spencer E; Peloquin, John M; Cortes, Daniel H; Kadlowec, Jennifer A; Soslowsky, Louis J; Elliott, Dawn M

    2012-02-01

    The heterogeneous composition and mechanical properties of the supraspinatus tendon offer an opportunity for studying the structure-function relationships of fibrous musculoskeletal connective tissues. Previous uniaxial testing has demonstrated a correlation between the collagen fiber angle distribution and tendon mechanics in response to tensile loading both parallel and transverse to the tendon longitudinal axis. However, the planar mechanics of the supraspinatus tendon may be more appropriately characterized through biaxial tensile testing, which avoids the limitation of nonphysiologic traction-free boundary conditions present during uniaxial testing. Combined with a structural constitutive model, biaxial testing can help identify the specific structural mechanisms underlying the tendon's two-dimensional mechanical behavior. Therefore, the objective of this study was to evaluate the contribution of collagen fiber organization to the planar tensile mechanics of the human supraspinatus tendon by fitting biaxial tensile data with a structural constitutive model that incorporates a sample-specific angular distribution of nonlinear fibers. Regional samples were tested under several biaxial boundary conditions while simultaneously measuring the collagen fiber orientations via polarized light imaging. The histograms of fiber angles were fit with a von Mises probability distribution and input into a hyperelastic constitutive model incorporating the contributions of the uncrimped fibers. Samples with a wide fiber angle distribution produced greater transverse stresses than more highly aligned samples. The structural model fit the longitudinal stresses well (median R(2) ≥ 0.96) and was validated by successfully predicting the stress response to a mechanical protocol not used for parameter estimation. The transverse stresses were fit less well with greater errors observed for less aligned samples. Sensitivity analyses and relatively affine fiber kinematics suggest that

  10. Apparatus for tensile testing plate-type ceramic specimens

    DOEpatents

    Liu, Kenneth C.

    1993-01-01

    Apparatus for tensile testing plate-type ceramic specimens having dogbone- or T-shaped end sections without introducing bending stresses in the specimens during the application of a dynamic tensile loading on the specimens is described. A pair of elongated pull rods disposed in a side-by-side relationship are used to grip the shoulders on each T-shaped end section. The pull rods are pivotally attached to a piston-displaceable, disk-shaped member so as to be longitudinally movable with respect to one another effecting the self-alignment thereof with the shoulders on the T-shaped end sections of the specimen to compensate for shoulders being located in different longitudinal positions.

  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. 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.

  13. 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.

  14. 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.

  15. Method and device for tensile testing of cable bundles

    DOEpatents

    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.

  16. Assessing the Applicability of Digital Image Correlation (DIC) Technique in Tensile Testing of Fabric Composites

    DTIC Science & Technology

    2013-02-01

    progression of strain on the tool side of the tensile sample. ....................................8 Figure 6. Results of the tensile testing of the basalt ...5 Table 2. The results of tensile testing for the basalt sample. ..........................................................5 Table 3. Line... basalt samples. .............................................................................10 1 1. Introduction Before novel structural

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Tensile mechanical properties tests of non-standard component in high temperature

    NASA Astrophysics Data System (ADS)

    Su, Wei; Liu, Renhuai; Song, Fangfang; Zhu, Junhua

    2017-05-01

    This paper makes research on tensile mechanical properties tests of heater component in electron gun. Tests are studied to get tensile property of heater component at the room and elevated temperature. Though improving test clamping appliance and experimental methods, discussing tensile fracture analysis, rupture mechanism is obtained by in situ observation using scanning electron microscope (SEM). To facilitate engineering application, materials suggestion is given at the end of the paper.

  11. 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.

  12. EVALUATION OF A RING TEST FOR DETERMINING THE TENSILE STRENGTH OF MORTARS AND CONCRETE.

    DTIC Science & Technology

    The purpose of this paper is to report the results of an evaluation of a specific type of test procedure, the ring tensile test , which results in a...strength’ and the techniques used to obtain them by other investigators over the years with the exception of the work involving the ring tensile test . Some

  13. Biaxial tensile tests of the porcine ascending aorta.

    PubMed

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

    2016-07-05

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. 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.

  15. 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.

  16. 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

  17. 10 Degree Off-Axis Tensile Test for Intralaminar Shear Characterization of Fiber Composites.

    DTIC Science & Technology

    1976-04-01

    A combined theoretical and experimental investigation was conducted to assess the suitability of the 10 deg off-axis tensile test specimen for the...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

  18. 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.

  19. 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.

  20. Newly Designed Tensile Test System for in vitro Measurement of Mechanical Properties of Cytoskeletal Filaments

    NASA Astrophysics Data System (ADS)

    Deguchi, Shinji; Ohashi, Toshiro; Sato, Masaaki

    A tensile test system for isolated cytoskeletal filaments, which enables to control strain rate, was newly designed. A pair of piezo-driven cantilevers were used to manipulate the specimen and to measure tensile load from the deflection of one of the cantilevers. The displacements of the cantilevers were optically and electrically detected. The specimen strain, determined from the cantilever displacements, was used as a feedback signal. We proposed a servo-system for strain rate control in which a desired path for the strain transition was designated. The path was chosen as a triangular-shape waveform against time, along which the strain rate is kept constant. We measured tensile properties of a single stress fiber isolated from a smooth muscle cell with this system to obtain a stretching stiffness of 45nN per strain. Performance evaluation and the tensile test demonstrated that the system enabled to carry out strain rate-controlled tensile test.

  1. [The properties of dentin and resinified dentin in the tensile test].

    PubMed

    Xu, J

    1989-07-01

    The purpose of this study is to evaluate the effect of resinifying therapy to the hard tissue of tooth by using measurement of the tensile strength. The fresh extracted maxillary anterior teeth having been cleaned and sterilized were divided into two groups. The control group was placed into 9% N-saline solution of 37 +/- 1 degrees C. The experimental group was treated with resinifying therapy. The tensile specimens were shaped by turning in a lathe until it satisfied the tensile test requirement of Mechanics of Materials except that they were hollow. A set of special split jig was made for this test. Instron Universal Testing Machine was used for measuring the load on the specimens. The loading speed was 0.05 mm/min. The straining meter was used to measure the tensile strain. The result revealed that tensile strength of resinifying dentin was little lower than that of unresinified dentin. The resinified dentin didn't increases stiffness or brittleness.

  2. 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.

  3. In situ EBSD during tensile test of aluminum AA3003 sheet.

    PubMed

    Kahl, Sören; Peng, Ru Lin; Calmunger, Mattias; Olsson, Björn; Johansson, Sten

    2014-03-01

    Miniature tensile-test specimens of soft-annealed, weakly textured AA3003 aluminum sheet in 0.9 mm thickness were deformed until fracture inside a scanning electron microscope. Tensile strength measured by the miniature tensile test stage agreed well with the tensile strength by regular tensile testing. Strain over the microscope field of view was determined from changes in positions of constituent particles. Slip lines were visible in secondary electron images already at 0.3% strain; activity from secondary slip systems became apparent at 2% strain. Orientation rotation behavior of the tensile load axis with respect to the crystallographic axes agreed well with previously reported trends for other aluminum alloys. Start of the fracture and tensile crack propagation were documented in secondary electron images. The region of fracture nucleation included and was surrounded by many grains that possessed high Schmid factors at zero strain. Crystal lattice rotation angles in the grains surrounding the initial fracture zone were higher than average while rotations inside the initial fracture zone were lower than average for strains from zero to 31%. The orientation rotation behavior of the tensile load axes of the grains around the fracture zone deviated from the average behavior in this material. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. 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.

  5. 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.

  6. Design and Validation of a Vacuum Assisted Anchorage for the Uniaxial Tensile Testing of Soft Materials.

    PubMed

    Blose, Kory J; Pichamuthu, Joseph E; Weinbaum, Justin S; Vorp, David A

    2016-01-01

    Current commercial tensile testing systems use spring-loaded or other compression-based grips to clamp materials in place posing a problem for very soft or delicate materials that cannot withstand this mechanical clamping force. In order to perform uniaxial tensile tests on soft tissues or materials, we have created a novel vacuum-assisted anchor (VAA). Fibrin gels were subjected to uniaxial extension, and the testing data was used to determine material mechanical properties. Utilizing the VAA, we achieved successful tensile breaks of soft fibrin gels while finding statistically significant differences between the mechanical properties of gels fabricated at two different fibrinogen concentrations.

  7. Design and Validation of a Vacuum Assisted Anchorage for the Uniaxial Tensile Testing of Soft Materials

    PubMed Central

    Blose, Kory J.; Pichamuthu, Joseph E.; Weinbaum, Justin S.; Vorp, David A.

    2016-01-01

    Current commercial tensile testing systems use spring-loaded or other compression-based grips to clamp materials in place posing a problem for very soft or delicate materials that cannot withstand this mechanical clamping force. In order to perform uniaxial tensile tests on soft tissues or materials, we have created a novel vacuum-assisted anchor (VAA). Fibrin gels were subjected to uniaxial extension, and the testing data was used to determine material mechanical properties. Utilizing the VAA, we achieved successful tensile breaks of soft fibrin gels while finding statistically significant differences between the mechanical properties of gels fabricated at two different fibrinogen concentrations. PMID:27795696

  8. A Surface Damage Investigation on Uniaxial Tensile Test Specimens Prepared by Common Cutting Methods

    DTIC Science & Technology

    1981-02-01

    REPORI’ A SURFACE DAMAGE INVESTIGATION ON UNIAXIAL TENSILE TEST SPECIMENSPREPARED BY COMMON CUTTING METHODS JUN 2 1931 THOMAS J. C. CHEW DALE A...Sýrfa-i-mage Investigation on Uniaxial Tensile Test Specimens Prepared by Common Cutting Method I Spi-.i t’ ,, ., • T7. AUTHORý#) . _" ’ /t’ .• r...Saw 10 2.1.3 Cutting by Milling Machine 11 2.1.4 Cutting by Die Cutter 11 2.2 Uniaxial Tensile Test 12 2.3 Electron Microscope Surface Examination 13 3

  9. 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.

  10. 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.

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

    SciTech Connect

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

    2006-03-31

    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 {alpha}-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.

  12. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  14. 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

  15. Cyclic flattened Brazilian disc tests for measuring the tensile fatigue properties of brittle rocks

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Dai, Feng; Xu, Nuwen; Zhao, Tao

    2017-08-01

    We propose a cyclic flattened Brazilian disc (FBD) testing method to measure the tensile fatigue properties of brittle rocks. Our method has obvious merits in its specimen preparation and experimental operation. Two parallel flattens are introduced in the disc specimen, which facilitate easily and uniformly loading the specimen without special loading devices required. Moreover, the contact regions between two flattens and loading planes barely change during the entire loading and unloading process, ensuring a consistent contact condition. With certain appropriate loading angles, this method guarantees that the very first breakage of the specimen occurs at the center of the disc, which is the prerequisite of the Brazilian-type indirect tensile tests. To demonstrate our new method, nine cyclic FBD tensile tests are conducted. The fatigue load-deformation characteristics of FBD specimens are revealed. The tensile fatigue lives of tested specimens are observed to increase with the increase in cyclic loading frequency. Our proposed method provides a convenient and reliable approach to indirectly measure the fatigue tensile properties of brittle rocks and other brittle solids subjected to cyclic tensile loadings.

  16. Cyclic flattened Brazilian disc tests for measuring the tensile fatigue properties of brittle rocks.

    PubMed

    Liu, Yi; Dai, Feng; Xu, Nuwen; Zhao, Tao

    2017-08-01

    We propose a cyclic flattened Brazilian disc (FBD) testing method to measure the tensile fatigue properties of brittle rocks. Our method has obvious merits in its specimen preparation and experimental operation. Two parallel flattens are introduced in the disc specimen, which facilitate easily and uniformly loading the specimen without special loading devices required. Moreover, the contact regions between two flattens and loading planes barely change during the entire loading and unloading process, ensuring a consistent contact condition. With certain appropriate loading angles, this method guarantees that the very first breakage of the specimen occurs at the center of the disc, which is the prerequisite of the Brazilian-type indirect tensile tests. To demonstrate our new method, nine cyclic FBD tensile tests are conducted. The fatigue load-deformation characteristics of FBD specimens are revealed. The tensile fatigue lives of tested specimens are observed to increase with the increase in cyclic loading frequency. Our proposed method provides a convenient and reliable approach to indirectly measure the fatigue tensile properties of brittle rocks and other brittle solids subjected to cyclic tensile loadings.

  17. [The direct tensile test of composite resins using the small specimen--effect of the preparation of specimen, the size of specimen and the testing condition on the tensile properties].

    PubMed

    Fujishima, A; Miyazaki, T; Kuneshita, H; Suzuki, E; Miyaji, T

    1990-09-01

    The direct tensile test of composite resins using the specimen with the gauge length 10 mm has been developed by authors. In this study smaller specimens with the gauge length 5 mm and 2 mm were also investigated. As the gauge length became smaller, tensile properties such as the proportional limit, the proof stress, and the tensile strength showed the tendency to become higher. The effect of strain rate on the tensile properties appeared clearly when using the specimen with the gauge length 2 mm. The small specimen was found to have many advantages for the preparation, the cost of material and the handling during the tensile test.

  18. Advances in post-necking flow curve identification of sheet metal through standard tensile testing

    NASA Astrophysics Data System (ADS)

    Coppieters, Sam; Cooreman, Steven; Debruyne, Dimitri; Kuwabara, Toshihiko

    2013-12-01

    The standard tensile test is still the most common material test to identify the hardening behavior of sheet metal. When using standard equipment and well-known analytical formulas, however, the hardening behavior can only be identified up to the point of maximum uniform elongation. Several methods which deal with the problem of extended flow curve identification of sheet metal through a tensile test have been proposed in the past. This paper gives an overview of the four classes of methods to identify post-necking hardening behavior of sheet metal through tensile testing. In addition, identification methods from the first (average values across the neck), second (Bridgeman correction, modified Siebel and Schwaigerer correction) and third class (special case of the VFM) are used to identify the post-necking hardening behavior of DC05. Finally, these results are used to assess the validity of the different methods.

  19. Mechanical tensile testing of titanium 15-3-3-3 and Kevlar 49 at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    James, B. L.; Martinez, R. M.; Shirron, P.; Tuttle, J.; Galassi, N. M.; McGuinness, D. S.; Puckett, D.; Francis, J. J.; Flom, Y.

    2012-06-01

    Titanium 15-3-3-3 and Kevlar 49 are highly desired materials for structural components in cryogenic applications due to their low thermal conductivity at low temperatures. Previous tests have indicated that titanium 15-3-3-3 becomes increasingly brittle as the temperature decreases. Furthermore, little is known regarding the mechanical properties of Kevlar 49 at low temperatures, most specifically its Young's modulus. This testing investigates the mechanical properties of both materials at cryogenic temperatures through cryogenic mechanical tensile testing to failure. The elongation, ultimate tensile strength, yield strength, and break strength of both materials are provided and analyzed here.

  20. 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.

  1. Mechanical state assessment using lamb wave technique in static tensile tests

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    The paper deals with the investigation of Lamb wave ultrasonic technique for damage (or mechanical state) evaluation of AA7068T3 specimens in the course of tensile testing. Two piezoelectric transducers (PZT), one of which is used as an actuator and the other as sensor, were adhesively bonded on the specimen surface using epoxy. Two frequencies of testing signals (60 kHz and 350 kHz) were used. The set of static tensile tests were performed. The recorded signals were processed to calculate the informative parameters in order to evaluate the changes in stress-strain state of the specimens and their microstructure.

  2. 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.

  3. Uniaxial tensile testing approaches for characterisation of atherosclerotic plaques.

    PubMed

    Walsh, M T; Cunnane, E M; Mulvihill, J J; Akyildiz, A C; Gijsen, F J H; Holzapfel, G A

    2014-03-03

    The pathological changes associated with the development of atherosclerotic plaques within arterial vessels result in significant alterations to the mechanical properties of the diseased arterial wall. There are several methods available to characterise the mechanical behaviour of atherosclerotic plaque tissue, and it is the aim of this paper to review the use of uniaxial mechanical testing. In the case of atherosclerotic plaques, there are nine studies that employ uniaxial testing to characterise mechanical behaviour. A primary concern regarding this limited cohort of published studies is the wide range of testing techniques that are employed. These differing techniques have resulted in a large variance in the reported data making comparison of the mechanical behaviour of plaques from different vasculatures, and even the same vasculature, difficult and sometimes impossible. In order to address this issue, this paper proposes a more standardised protocol for uniaxial testing of diseased arterial tissue that allows for better comparisons and firmer conclusions to be drawn between studies. To develop such a protocol, this paper reviews the acquisition and storage of the tissue, the testing approaches, the post-processing techniques and the stress-strain measures employed by each of the nine studies. Future trends are also outlined to establish the role that uniaxial testing can play in the future of arterial plaque mechanical characterisation.

  4. Determination of tensile and compressive moduli of laminae in unidirectionally reinforced laminate by flexural tests

    NASA Astrophysics Data System (ADS)

    Kuklinski, Mariusz

    2017-03-01

    The Euler-Bernoulli beam theory is widely used in engineering despite of various simplifications. One of which, that do matters in this article, is neglecting the difference between tensile and compressive moduli. Experimental tests reveal that for fibre reinforced composites tensile moduli are generally greater than compressive ones. This paper presents the results of testing the laminate composed of four unidirectionally glass reinforced laminae separated by layers of glass mat. The specimens were subjected to flexural, tensile and compressive loading in order to calculate corresponding moduli of elasticity. The results were compared using equations of Classical Beam Theory. Knowing the tensile and compressive moduli of glass mat reinforced laminae and performing flexural tests of laminate it is possible to calculate the tensile and compressive moduli of unidirectionally glass reinforced laminae. The experimental data taken into calculations correspond to linear normal strains of 0.0005 and 0.0025. The experimental data are consistent with results of calculations within acceptable margin of tolerance.

  5. 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.

  6. 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.

  7. Finite Element Simulations for Investigating the Effects of Specimen Geometry in Superplastic Tensile Tests

    NASA Astrophysics Data System (ADS)

    Nazzal, Mohammad; Abu-Farha, Fadi; Curtis, Richard

    2011-08-01

    Characterizing the behavior of superplastic materials is largely based on the uniaxial tensile test; yet the unique nature of these materials requires a particularly tailored testing methodology, different to that used with conventional materials. One of the crucial testing facets is the specimen geometry, which has a great impact on the outcome of a superplastic tensile test, as a result of the associated extreme conditions. And while researchers agree that it should take a notably different form than the typical dog-bone shape; there is no universal agreement on the specimen's particular size and dimensions, as evident by the disparities in test specimens used in the various superplastic testing efforts found throughout the literature. In view of that, this article is dedicated to understanding the effects of specimen geometry on the superplastic behavior of the material during tensile testing. Deformation of the Ti6Al4V titanium alloy is FE simulated based on a multitude of specimen geometries, covering a wide range of gauge length, gauge width, grip length, and grip width values. The study provides key insights on the influences of each geometrical parameter as well as their interactions, and provides recommendations on selecting the specimen's proportions for accurate and unified tensile testing of superplastic materials.

  8. A novel tensile test method to assess texture and gaping in salmon fillets.

    PubMed

    Ashton, Thomas J; Michie, Ian; Johnston, Ian A

    2010-05-01

    A new tensile strength method was developed to quantify the force required to tear a standardized block of Atlantic salmon muscle with the aim of identifying those samples more prone to factory downgrading as a result of softness and fillet gaping. The new method effectively overcomes problems of sample attachment encountered with previous tensile strength tests. The repeatability and sensitivity and predictability of the new technique were evaluated against other common instrumental texture measurement methods. The relationship between sensory assessments of firmness and parameters from the instrumental texture methods was also determined. Data from the new method were shown to have the strongest correlations with gaping severity (r =-0.514, P < 0.001) and the highest level of repeatability of data when analyzing cold-smoked samples. The Warner Bratzler shear method gave the most repeatable data from fresh samples and had the highest correlations between fresh and smoked product from the same fish (r = 0.811, P < 0.001). A hierarchical cluster analysis placed the tensile test in the top cluster, alongside the Warner Bratzler method, demonstrating that it also yields adequate data with respect to these tests. None of the tested sensory analysis attributes showed significant relationships to mechanical tests except fillet firmness, with correlations (r) of 0.42 for cylinder probe maximum force (P = 0.005) and 0.31 for tensile work (P = 0.04). It was concluded that the tensile test method developed provides an important addition to the available tools for mechanical analysis of salmon quality, particularly with respect to the prediction of gaping during factory processing, which is a serious commercial problem. A novel, reliable method of measuring flesh tensile strength in salmon, provides data of relevance to gaping.

  9. 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.

  10. High Velocity Tensile Test for Thin Plate Specimen with One Bar Method

    NASA Astrophysics Data System (ADS)

    Itabashi, Masaaki

    In order to design thin-walled impact-resistant structure, for example, an automotive body, dynamic behavior of thin plate is essential. So far, except for laminated composite materials, high velocity tensile test of thin plate specimen did not attract impact researchers' and engineers' attention very much. In this paper, the previous thin plate specimen assembly for the one bar method was improved. The one bar method has been utilized for cylindrical specimens of various solid materials and is known as an effective high velocity tensile testing technique. Unfortunately, the previous assembly introduced a tremendous initial peak on stress-strain curves, even for aluminum alloys. With a new specimen assembly, stress-strain curves for IF (Interstitial-atom Free) steel and 7075-T6 aluminum alloy obtained by the one bar method were almost equivalent to those obtained by the tensile version of the split Hopkinson pressure bar method.

  11. Tensile tests and metallography of brazed AISI 316L specimens after irradiation

    NASA Astrophysics Data System (ADS)

    Groot, P.; Franconi, E.

    1994-08-01

    Stainless steel type 316L tensile specimens were vacuum brazed with three kinds of alloys: BNi-5, BNi-6, and BNi-7. The specimens were irradiated up to 0.7 dpa at 353 K in the High Flux Reactor at JRC Petten, the Netherlands. Tensile tests were performed at a constant displacement rate of 10 -3 s -1 at room temperature in the ECN hot cell facility. BNi-5 brazed specimens showed ductile behaviour. Necking and fractures were localized in the plate material. BNi-6 and BNi-7 brazed specimens failed brittle in the brazed zone. This was preceded by uniform deformation of the plate material. Tensile test results of irradiated specimens showed higher stresses due to radiation hardening and a reduction of the elongation of the plate material compared to the reference. SEM examination of the irradiated BNi-6 and BNi-7 fracture surfaces showed nonmetallic phases. These phases were not found in the reference specimens.

  12. ATI SAA Annex 3 Button Tensile Test Report I

    NASA Technical Reports Server (NTRS)

    Tang, Henry H.

    2013-01-01

    This report documents the results of a study carried out under Splace Act Agreement SAA-EA-10-004 between the National Aeronautics and Space Administration (NASA) and Astro Technology Incorpporated (ATI). NASA and ATI have entered into this agreement to collaborate on the development of technologies that can benefit both the US government space programs and the oil and gas industry. The report documents the results of a test done on an adnesive system for attaching new monitoring sensor devices to pipelines under Annex III of SAA-EA-10-004: "Proof-of-Concept Design and Testing of a Post Installed Sensing Device on Subsea Risers and Pipelines". The tasks of Annex III are to design and test a proof-of-concept sensing device for in-situ installation on pipelines, risers, or other structures deployed in deep water. The function of the sensor device is to measure various signals such as strain, stress and temperature. This study complements the work done, in Annex I of the SAA, on attaching a fiber optic sensing device to pipe via adhesive bonding. Both Annex I and Annex III studies were conducted in the Crew and Thermal System Division (CTSD) at the Johnson Space Center (JSC) in collaboration with ATI.

  13. 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.

  14. 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.

  15. Rheological behaviour of commercial cooked meat products evaluated by tensile test and texture profile analysis (TPA).

    PubMed

    Romero de Ávila, M Dolores; Isabel Cambero, M; Ordóñez, Juan A; de la Hoz, Lorenzo; Herrero, Ana M

    2014-10-01

    The breaking strength (BS) and energy to fracture (EF) of commercial cooked meat products (CMP) manufactured from different entire pieces were determined by tensile test. BS and EF were related to texture profile analysis (TPA) and physico-chemical data. Two textural profiles were characterized mainly by BS, springiness adhesiveness and fat content. Multivariate regression analysis confirms that TPA parameters could be used to construct models to predict BS and EF. Therefore, just one TPA analysis will allow to obtain both TPA and tensile parameters, providing valuable information about mechanical behaviour to improve product handling at industrial level especially in sliced CMP. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Novel temperature dependent tensile test of freestanding copper thin film structures.

    PubMed

    Smolka, M; Motz, C; Detzel, T; Robl, W; Griesser, T; Wimmer, A; Dehm, G

    2012-06-01

    The temperature dependent mechanical properties of the metallization of electronic power devices are studied in tensile tests on micron-sized freestanding copper beams at temperatures up to 400 °C. The experiments are performed in situ in a scanning electron microscope. This allows studying the micromechanical processes during the deformation and failure of the sample at different temperatures.

  17. 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.

  18. Test report: effect of specimen orientation and location on the tensile properties of GTS forging 1472859

    SciTech Connect

    Melcher, Ryan J

    2008-02-12

    ASTM standardized tensile tests were performed on GTS WR-quality 1472859 forging (21-6- 9 material) to determine the dependence of tensile properties on specimen orientation (longitudinal vs. transverse) with respect to forging ‘grain flow’ and location within the forging. Statistical analyses of the results show that location has a statistically measurable effect on the longitudinal tensile properties (as compared to the error involved in tensile testing). However, this dependence of the properties with location, especially in the circumferential orientation, causes large variability in the results that clouds the statistical determination of any orientation effect. As a result, this forging is determined to be inhomogeneous along the forging length, with a significant range in properties observed (e.g. yield strengths from 85 to 117 ksi) and highest strength/lowest ductility in the spherical region. Additional specimens should be tested to acquire a higher resolution view of this inhomogeneity if the end use of the data is structural integrity analyses using spatially dependent properties; however, sufficient data is provided in this study to extract a statistical lower bound for conservative, homogeneous structural analysis.

  19. 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.

  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. Comparative tensile and torsion tests as a method of determination of the crack growth mechanism in corrosion cracking

    SciTech Connect

    Marichev, V.A.

    1987-11-01

    The author present and review tensile and torsional testing techniques for determining the contribution of electrochemical corrosion and hydrogen embrittlement to the mechanics of crack propagation in aluminium and molybdenum alloys and in a nickel-chromium steel. They suggest and analyze testing parameters and considerations whose implementations are shown to increase the accuracy of tensile and torsion determinations of fracture and embrittlement behavior.

  2. In situ micro-tensile testing on proton beam-irradiated stainless steel

    NASA Astrophysics Data System (ADS)

    Vo, H. T.; Reichardt, A.; Frazer, D.; Bailey, N.; Chou, P.; Hosemann, P.

    2017-09-01

    Small-scale mechanical testing techniques are currently being explored and developed for engineering applications. In particular, micro-tensile testing can add tremendous value, since the entire stress-strain curve, including the strain to failure, can be measured directly. In this work, 304 stainless steel specimens irradiated with 2 MeV protons to 10 dpa (full-cascade setting in the Stopping and Range of Ions in Matter, SRIM, software) at 360 °C was evaluated using micro-tensile testing. It was found that even on the micron scale, the measured strain corresponds well with macroscopic expectations. In addition, a new approach to analyzing sudden slip events is presented.

  3. 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.

  4. Investigation of the applicability of a tensile testing machine for measuring mucoadhesive strength.

    PubMed

    Dyvik, K; Graffner, C

    1992-01-01

    The applicability of a tensile testing machine (M30K, JJ Lloyd Instruments Ltd, GB) is investigated for measuring mucoadhesive strengths. A sample of an aqueous dispersion of a polymer with expected mucoadhesive properties is placed between two homemade discs of polyoxymethylene. The upper disc is mounted on a movable part of the machine while the lower disc is fixed on the stationary frame. A tensile force is submitted and the maximum detachment force at fracture and the adhesion work are estimated from the force displacement curve recorded. In some experiments, native mucous tissue of the large intestine of pigs was glued to the upper disc. Four polymers polycarbophil (Carbopol EX-55), carboxypolymethylene (Carbopol 934P), hydroxypropylmethylcellulose (Methocel K4M), and sodium alginate, are used in five different concentrations. At least three measurements are made of each polymer and concentration. Viscosity and osmolality are determined. By standardizing the time of sample equilibration and the run rate before measurement, it is possible to get good reproducibility of the tensile values. Based on the maximum nominal breaking force and the work consumed, it is concluded that the tensile strength is dependent both on the concentration and the type of polymer. The conclusions are the same independent of whether mucous pig tissue is used, or not. The same rank order in adhesive properties of the polymers is achieved as from using modified surface tensiometers.

  5. A tensile test to facilitate identification of defects in dentine bonded specimens.

    PubMed

    Nakabayashi, N; Watanabe, A; Arao, T

    1998-05-01

    To determine the efficacy of a miniaturized dumbbell test procedure designed to more easily identify defect(s) in bonded dentine test specimens. Extracted human dentine substrates were pre-conditioned with 10-3 solution for 10, 30 or 60 s prior to dentine bonding with 4-META/MMA-TBB resin. Miniaturized dumbbell-shaped test specimens were prepared from the resin bonded samples. After 24 h storage in 37 degrees C water, the specimens were tensile-loaded to failure. Fractured surfaces and cross-sections were examined and compared under scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Cohesive failure within the bonding resin was observed in specimens pre-conditioned for 10 s. The tensile bond strength of these was excellent. Bond strengths of specimens that were pre-conditioned for 30 and 60 s were significantly lower, and defects in these specimens, formerly difficult or impossible to identify, were readily identified under SEM and TEM microscopy. The proposed method of tensile stressing to failure and microscopically examining fractured miniaturized dumbbell-shaped test specimens is a simple and reproducible test procedure. The protocol is capable of clearly elucidating defective resin infiltration of demineralized dentine in bonded interfaces. These defects are difficult to visualize by conventional and/or ISO recommended methods.

  6. A Microsample Tensile Test Application: Local Strength of Impact Welds Between Sheet Metals

    NASA Astrophysics Data System (ADS)

    Benzing, J. T.; He, M.; Vivek, A.; Taber, G. A.; Mills, M. J.; Daehn, G. S.

    2017-03-01

    Microsample tensile testing was conducted to evaluate the quality of impact welds created by vaporizing foil actuator welding. Tensile test samples with a gauge length of 0.6 mm were electro-discharge machined out of welds created between 1-mm-thick aluminum alloy type 6061 (AA6061) sheets and 6-mm-thick copper (Cu110) plates. Aluminum sheets were used as flyers, while copper plates acted as targets. Flyer sheets in T6 as well as T4 temper conditions were utilized to create welds. Some of the welds made with T4 temper flyers were heat treated to a T6 temper. It was found that the welds made with T4 temper flyers were slightly stronger (max. of 270 MPa) than those produced with T6 temper flyers. Generally, failure propagated in a brittle manner across the weld interface; however, elemental mapping reveals material transfer on either member of the welded system. This work proves the feasibility to apply microsample tensile testing to assess impact welding, even when conducted with flyer sheets of 1 mm or less, and provides insight that is complementary to other test methods.

  7. 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.

  8. A Microsample Tensile Test Application: Local Strength of Impact Welds Between Sheet Metals

    NASA Astrophysics Data System (ADS)

    Benzing, J. T.; He, M.; Vivek, A.; Taber, G. A.; Mills, M. J.; Daehn, G. S.

    2017-01-01

    Microsample tensile testing was conducted to evaluate the quality of impact welds created by vaporizing foil actuator welding. Tensile test samples with a gauge length of 0.6 mm were electro-discharge machined out of welds created between 1-mm-thick aluminum alloy type 6061 (AA6061) sheets and 6-mm-thick copper (Cu110) plates. Aluminum sheets were used as flyers, while copper plates acted as targets. Flyer sheets in T6 as well as T4 temper conditions were utilized to create welds. Some of the welds made with T4 temper flyers were heat treated to a T6 temper. It was found that the welds made with T4 temper flyers were slightly stronger (max. of 270 MPa) than those produced with T6 temper flyers. Generally, failure propagated in a brittle manner across the weld interface; however, elemental mapping reveals material transfer on either member of the welded system. This work proves the feasibility to apply microsample tensile testing to assess impact welding, even when conducted with flyer sheets of 1 mm or less, and provides insight that is complementary to other test methods.

  9. 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.

  10. 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.

  11. Ethylene propylene cable degradation during LOCA research tests: tensile properties at the completion of accelerated aging

    SciTech Connect

    Bustard, L.D.

    1982-05-01

    Six ethylene-propylene rubber (EPR) insulation materials were aged at elevated temperature and radiation stress exposures common in cable LOCA qualification tests. Material samples were subjected to various simultaneous and sequential aging simulations in preparation for accident environmental exposures. Tensile properties subsequent to the aging exposure sequences are reported. The tensile properties of some, but not all, specimens were sensitive to the order of radiation and elevated temperature stress exposure. Other specimens showed more severe degradation when simultaneously exposed to radiation and elevated temperature as opposed to the sequential exposure to the same stresses. Results illustrate the difficulty in defining a single test procedure for nuclear safety-related qualification of EPR elastomers. A common worst-case sequential aging sequence could not be identified.

  12. 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.

  13. 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

  14. 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).

  15. Modeling of tensile testing on perfect and defective graphenylene nanotubes using molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Rouhi, Saeed

    2017-08-01

    Molecular dynamics simulations are employed here to study the mechanical properties of graphenylene nanotubes (NTs). The effects of different geometrical parameters, such as NT length and diameter, on the behavior of graphenylene NTs under tensile testing are investigated. Moreover, the tensile test is simulated at several temperatures, to obtain the stress-strain curves of both armchair and zigzag graphenylene NTs. It is shown that graphenylene NTs with larger diameter possess larger elastic moduli. The elastic modulus of graphenylene NTs is about one half that of carbon NTs. However, the maximum tolerable stress and strain of the graphenylene NTs decreases with increasing NT diameter. Investigating the effect of vacancy defects on the elastic properties of the graphenylene NTs, it is shown that Young’s modulus of armchair and zigzag graphenylene NTs decreases nonlinearly with increasing defect percentages.

  16. Necking of Q&P steel during uniaxial tensile test with the aid of DIC technique

    NASA Astrophysics Data System (ADS)

    Ding, Lei; Lin, Jianping; Min, Junying; Pang, Zheng; Ye, You

    2013-05-01

    A lot of research has been focused on the necking process during the plastic deformation of sheet metals, but the localized necking is rarely distinguished form diffused necking by experiments, due to the limit of measurement equipment and method. Quenching and Partitioning (Q&P) steel is a 3rd generation advanced high strength steel (AHSS). Its good combination of high strength and ductility ensures potential application in automobile industry. Uniaxial tensile tests of QP980 steel sheet at five strain rates are performed to investigate the necking process and the effect of strain rate on necking behavior of Q&P steel. Digital image correlation (DIC) method is applied during tensile tests, and evolutions of major strain, minor strain and normal strain distributions along gauge section of the tensile specimens are obtained. The diffused and localized necking strains are determined according to SWIFT necking theory and HILL necking theory respectively. The test results indicate that with the increasing of strain rate in the investigated range, the diffused necking strain decreases from 0.152 to 0.120 and localized necking strain decreases from 0.245 to 0.137. Meanwhile, the difference of the two strains decreases form 0.096 to 0.017. Thus it can be concluded that strain rate has an influence on both necking strains during the deformation of QP980 steel sheet. Diffused and localized necking strains are determined by uniaxial tensile tests with the aid of DIC technique and the effect of strain rate on necking strains is evaluated.

  17. Thermal and tensile strength testing of thermally-conductive adhesives and carbon foam

    NASA Astrophysics Data System (ADS)

    Chertok, M.; Fu, M.; Irving, M.; Neher, C.; Shi, M.; Tolfa, K.; Tripathi, M.; Vinson, Y.; Wang, R.; Zheng, G.

    2017-01-01

    Future collider detectors, including silicon tracking detectors planned for the High Luminosity LHC, will require components and mechanical structures providing unprecedented strength-to-mass ratios, thermal conductivity, and radiation tolerance. This paper studies carbon foam used in conjunction with thermally conductive epoxy and thermally conductive tape for such applications. Thermal performance and tensile strength measurements of aluminum-carbon foam-adhesive stacks are reported, along with initial radiation damage test results.

  18. Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing

    PubMed Central

    Griffin, Michelle; Premakumar, Yaami; Seifalian, Alexander; Butler, Peter Edward; Szarko, Matthew

    2016-01-01

    Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions. This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes. PMID:28060331

  19. Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing.

    PubMed

    Griffin, Michelle; Premakumar, Yaami; Seifalian, Alexander; Butler, Peter Edward; Szarko, Matthew

    2016-12-13

    Regenerative medicine aims to engineer materials to replace or restore damaged or diseased organs. The mechanical properties of such materials should mimic the human tissues they are aiming to replace; to provide the required anatomical shape, the materials must be able to sustain the mechanical forces they will experience when implanted at the defect site. Although the mechanical properties of tissue-engineered scaffolds are of great importance, many human tissues that undergo restoration with engineered materials have not been fully biomechanically characterized. Several compressive and tensile protocols are reported for evaluating materials, but with large variability it is difficult to compare results between studies. Further complicating the studies is the often destructive nature of mechanical testing. Whilst an understanding of tissue failure is important, it is also important to have knowledge of the elastic and viscoelastic properties under more physiological loading conditions. This report aims to provide a minimally destructive protocol to evaluate the compressive and tensile properties of human soft tissues. As examples of this technique, the tensile testing of skin and the compressive testing of cartilage are described. These protocols can also be directly applied to synthetic materials to ensure that the mechanical properties are similar to the native tissue. Protocols to assess the mechanical properties of human native tissue will allow a benchmark by which to create suitable tissue-engineered substitutes.

  20. 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.

  1. 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

  2. Strength, Hardening, and Failure Observed by In Situ TEM Tensile Testing.

    PubMed

    Kiener, Daniel; Kaufmann, Petra; Minor, Andrew M

    2012-11-01

    We present in situ transmission electron microscope tensile tests on focused ion beam fabricated single and multiple slip oriented Cu tensile samples with thicknesses in the range of 100-200 nm. Both crystal orientations fail by localized shear. While failure occurs after a few percent plastic strain and limited hardening in the single slip case, the multiple slip samples exhibit extended homogenous deformation and necking due to the activation of multiple dislocation sources in conjunction with significant hardening. The hardening behavior at 1% plastic strain is even more pronounced compared to compression samples of the same orientation due to the absence of sample taper and the interface to the compression platen. Moreover, we show for the first time that the strain rate sensitivity of such FIB prepared samples is an order of magnitude higher than that of bulk Cu.

  3. Application of a tensile-strength test method to the evaluation of hydrating hair products.

    PubMed

    Mercelot, V

    1998-08-01

    The usual methods applied to studying the hydration state of hair (e.g. gravimetry, microscopy, evaporimetry) are mostly concerned with a limited area of the fibre. Consequently, the results obtained do not reflect the variability of the physicochemical properties of the whole fibre. Moreover, there are not many experimental methods to evaluate the hydrating power of hair care products in the literature. This study proposes a new method to measure the hydration state of treated or untreated hair by using a tensile strength test. A graphic analysis of tensile strength variation as a function of relative humidity after hair treatment allows the calculation of three hydration indexes: protection index, instant hydration index and permanent hydration index. This technique can give useful information on the behaviour of hair versus relative humidity and on the different hydrating mechanisms exhibited by hair care products.

  4. On loading velocity oscillations during dynamic tensile testing with flying wheel systems

    NASA Astrophysics Data System (ADS)

    Erice, Borja; Roth, Christian; Gary, Gerard; Mohr, Dirk

    2015-09-01

    Flying Wheels (FW) provide a space-saving alternative to Split Hopkinson Bar (SHB) systems for generating the loading pulse for intermediate and high strain rate material testing. This is particularly attractive in view of performing ductile fracture experiments at intermediate strain rates that require a several milliseconds long loading pulse. More than 50 m long Hopkinson bars are required in that case, whereas the same kinetic energy (for a given loading velocity) can be stored in rather compact flying wheels (e.g. diameter of less than 1.5 m). To gain more insight into the loading capabilities of FW tensile testing systems, a simple analytical model is presented to analyze the loading history applied by a FW system. It is found that due to the presence of a puller bar that transmits the tensile load from the rotating wheel to the specimen, the loading velocity applied onto the specimen oscillates between about zero and twice the tangential loading speed applied by the FW. The theoretical and numerical evaluation for a specific 1.1 m diameter FW system revealed that these oscillations occur at a frequency in the kHz range, thereby questioning the approximate engineering assumption of a constant strain rate in FW tensile experiments at strain rates of the order of 100/s.

  5. Direct Shear Tests of Sandstone Under Constant Normal Tensile Stress Condition Using a Simple Auxiliary Device

    NASA Astrophysics Data System (ADS)

    Cen, Duofeng; Huang, Da

    2017-06-01

    Tension-shear failure is a typical failure mode in the rock masses in unloading zones induced by excavation or river incision, etc., such as in excavation-disturbed zone of deep underground caverns and superficial rocks of high steep slopes. However, almost all the current shear failure criteria for rock are usually derived on the basis of compression-shear failure. This paper proposes a simple device for use with a servo-controlled compression-shear testing machine to conduct the tension-shear tests of cuboid rock specimens, to test the direct shear behavior of sandstone under different constant normal tensile stress conditions ( σ = -1, -1.5, -2, -2.5 and -3 MPa) as well as the uniaxial tension behavior. Generally, the fracture surface roughness decreases and the proportion of comminution areas in fracture surface increases as the change of stress state from tension to tension-shear and to compression-shear. Stepped fracture is a primary fracture pattern in the tension-shear tests. The shear stiffness, shear deformation and normal deformation (except the normal deformation for σ = -1 MPa) decrease during shearing, while the total normal deformation containing the pre-shearing portion increases as the normal tensile stress level (| σ|) goes up. Shear strength is more sensitive to the normal tensile stress than to the normal compressive stress, and the power function failure criterion (or Mohr envelope form of Hoek-Brown criterion) is examined to be the optimal criterion for the tested sandstone in the full region of tested normal stress in this study.

  6. 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.

  7. In situ tensile testing of nanofibers by combining atomic force microscopy and scanning electron microscopy.

    PubMed

    Hang, Fei; Lu, Dun; Bailey, Russell J; Jimenez-Palomar, Ines; Stachewicz, Urszula; Cortes-Ballesteros, Beatriz; Davies, Martin; Zech, Martin; Bödefeld, Christoph; Barber, Asa H

    2011-09-07

    A nanomechanical testing set-up is developed by integrating an atomic force microscope (AFM) for force measurements with a scanning electron microscope (SEM) to provide imaging capabilities. Electrospun nanofibers of polyvinyl alcohol (PVA), nylon-6 and biological mineralized collagen fibrils (MCFs) from antler bone were manipulated and tensile-tested using the AFM-SEM set-up. The complete stress-strain behavior to failure of individual nanofibers was recorded and a diversity of mechanical properties observed, highlighting how this technique is able to elucidate mechanical behavior due to structural composition at nanometer length scales.

  8. Methodology to determine failure characteristics of planar soft tissues using a dynamic tensile test.

    PubMed

    Jacquemoud, C; Bruyere-Garnier, K; Coret, M

    2007-01-01

    Predicting the injury risk in automotive collisions requires accurate knowledge of human tissues, more particularly their mechanical properties under dynamic loadings. The present methodology aims to determine the failure characteristics of planar soft tissues such as skin, hollow organs and large vessel walls. This consists of a dynamic tensile test, which implies high-testing velocities close to those in automotive collisions. To proceed, I-shaped tissue samples are subjected to dynamic tensile tests using a customized tensile device based on the drop test principle. Data acquisition has especially been adapted to heterogeneous and soft biological tissues given that standard measurement systems (considered to be global) have been completed with a non-contact and full-field strain measurement (considered to be local). This local measurement technique, called the Image Correlation Method (ICM) provides an accurate strain analysis by revealing strain concentrations and avoids damaging the tissue. The methodology has first been applied to human forehead skin and can be further expanded to other planar soft tissues. The failure characteristics for the skin in terms of ultimate stress are 3 MPa +/- 1.5 MPa. The ultimate global longitudinal strains are equal to 9.5%+/-1.9% (Green-Lagrange strain), which contrasts with the ultimate local longitudinal strain values of 24.0%+/-5.3% (Green-Lagrange strain). This difference is a consequence of the tissue heterogeneity, clearly illustrated by the heterogeneous distribution of the local strain field. All data will assist in developing the tissue constitutive law that will be implemented in finite element models.

  9. 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.

  10. 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

    2015-09-09

    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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Tensile strength testing for resorbable mesh fixation systems in laparoscopic ventral hernia repair.

    PubMed

    Reynvoet, Emmelie; Berrevoet, Frederik; De Somer, Filip; Vercauteren, Griet; Vanoverbeke, Ingrid; Chiers, Koen; Troisi, Roberto

    2012-09-01

    In an attempt to improve patient outcome and quality of life after laparoscopic ventral hernia repair, resorbable fixation devices have been developed to allow adequate mesh fixation while minimizing accompanying side-effects as tack erosion and adhesion formation. In experimental set-up, 24 pigs were treated by laparoscopic mesh placement. Two different meshes (PP/ORC and PP/ePTFE) and four fixation devices were evaluated: a 6.4 mm poly(D,L: )-lactide pushpin (tack I), a 6.8 mm poly(D,L: )-lactide with blunt tip (tack II), a 4.1 mm poly(glycolide-co-L-lactide) (tack III) and one titanium tack (control tack). A first group of animals (n = 12) was euthanized after 2 weeks survival and a second group (n = 12) after 6 months. At euthanasia, a relaparoscopy was performed to assess adhesion formation followed by laparotomy with excision of the entire abdominal wall. Tensile strength of the individual fixation systems was tested with the use of a tensiometer by measuring the force to pull the tack out of the mesh. Additionally, the foreign body reaction to the fixation systems was evaluated histologically as was their potential degradation. At 2 weeks the tensile strength was significantly higher for the control tack (31.98 N/cm²) compared to the resorbable devices. Except for tack II, the tensile strength was higher when the devices were fixed in a PP/ePTFE mesh compared to the PP/ORC mesh. After 6 months only tack III was completely resorbed, while tack I (9.292 N/cm²) had the lowest tensile strength. At this time-point similar tensile strength was observed for both tack II (29.56 N/cm²) and the control tack (27.77 N/cm²). Adhesions seem to be more depending on the type of mesh, in favor of PP/ePTFE. At long term, the 4.1 mm poly(glycolide-co-L-lactide) tack was the only tack completely resorbed while the 6.8 mm poly(D,L: )-lactide tack with blunt tip reached equal strengths to the permanent tack.

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

    NASA Astrophysics Data System (ADS)

    Yoo, Jin-Hyeong; Flatau, Alison B.

    2005-05-01

    An experimental approach is used to identify Galfenol material properties under dc magnetic bias fields. Dog-bone-shaped specimens of single crystal Fe100-xGax, 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.

  17. An Analytical Approach For Earing In Cylindrical Deep Drawing Based On Uniaxial Tensile Test Results

    NASA Astrophysics Data System (ADS)

    Mulder, J.; Vegter, H.

    2011-05-01

    The prediction of earing and wall thickness distribution in cylindrical deep drawing is a challenging task even for today's FEA programs with advanced yield loci like Yld2004-18p, BBC2003 or Vegter. The current work involves an analytical description of cylindrical deep drawing that is comparable in accuracy to advanced numerical models. The analytical approach shows the importance for these type of simulations of fitting the yield locus description to uniaxial tensile test results in different directions, considering the full hardening curves.

  18. 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.

  19. 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.

  20. 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.

  1. Strain measurement technique for elevated temperature tensile and creep testing of foil-gage metals

    NASA Technical Reports Server (NTRS)

    Blackburn, L. B.

    1988-01-01

    This paper describes a strain measurement technique suitable for elevated-temperature tensile and creep testing of foil-gage metals, using a modified commonly available mechanical extensometer in conjunction with a displacement transducer. The extensometer was modified by attaching to it a counterbalance (to reduce the effect of the extensometer weight on the total maximum test load) and by incorporating a conical tip/flat-edge design (to minimize induced stresses in the specimen resulting from extensometer attachment). Creep tests were performed on 0.102-mm-thick specimens of Ti-6Al-4V at temperatures of 427 and 538 C, at nominal applied stresses of 310.3 and 172.4 MPa, respectively. Examination of the resulting creep curves suggested that the strain measurement system provided actual creep strain values with good accuracy.

  2. Validating material modelling for OFHC copper using dynamic tensile extrusion (DTE) test at different velocity impact

    NASA Astrophysics Data System (ADS)

    Bonora, N.; Testa, G.; Ruggiero, A.; Iannitti, G.; Colliander, M. Hörnquist; Mortazavi, N.

    2017-01-01

    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 the modified Rusinek-Klepaczko model, are presented. Simulation of microstructure evolution was performed using the visco-plastic self consistent model (VPSC), providing, as input, the velocity gradient history obtained with FEM at selected locations along the axis of the fragment trapped in the extrusion die. Finally, results are compared with EBSD analysis.

  3. 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.

  4. 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.

  5. Constitutive modeling of the dynamic-tensile-extrusion test of PTFE

    NASA Astrophysics Data System (ADS)

    Resnyansky, A. D.; Brown, E. N.; Trujillo, C. P.; Gray, G. T.

    2017-01-01

    Use of polymers in defense, aerospace and industrial applications under extreme loading conditions makes prediction of the behavior of these materials very important. Crucial to this is knowledge of the physical damage response in association with phase transformations during loading and the ability to predict this via multi-phase simulation accounting for thermodynamical non-equilibrium and strain rate sensitivity. The current work analyzes Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) experiments on polytetrafluoroethylene (PTFE). In particular, the phase transition during loading and subsequent tension are analyzed using a two-phase rate sensitive material model implemented in the CTH hydrocode. The calculations are compared with experimental high-speed photography. Deformation patterns and their link with changing loading modes are analyzed numerically and correlated to the test observations. It is concluded that the phase transformation is not as critical to the response of PTFE under Dyn-Ten-Ext loading as it is during the Taylor rod impact testing.

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

    SciTech Connect

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

    2011-05-04

    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.

  7. Experimental Investigation of Tensile Test on Connection of Cold-formed Cut-curved Steel Section

    NASA Astrophysics Data System (ADS)

    Sani, Mohd Syahrul Hisyam Mohd; Muftah, Fadhluhartini; Rahman, Nurul Farraheeda Abdul; Fakri Muda, Mohd

    2017-08-01

    Cold-formed steel (CFS) is widely used as structural and non-structural components such as roof trusses and purlin. A CFS channel section with double intermediate web stiffener and lipped is chosen based on the broader usage in roof truss construction. CFS section is cut to form cold-formed pre-cut-curved steel section and lastly strengthened by several types of method or likely known as connection to establish the cold-formed cut-curved steel (CFCCS) section. CFCCS is proposed to be used as a top chord section in the roof truss system. The CFCCS is to resist the buckling phenomena of the roof truss structure and reduced the compression effect on the top chord. The tensile test connection of CFCCS section, especially at the flange element with eight types of connection by welding, plate with self-drilling screw and combination is investigated. The flange element is the weakest part that must be solved first other than the web element because they are being cut totally, 100% of their length for curving process. The testing is done using a universal testing machine for a tensile load. From the experiment, specimen with full welding has shown as a good result with an ultimate load of 13.37 kN and reported having 35.41% when compared with normal specimen without any of connection methods. Furthermore, the experimental result is distinguished by using Eurocode 3. The failure of a full welding specimen is due to breaking at the welding location. Additionally, all specimens with either full weld or spot weld or combination failed due to breaking on weld connection, but specimen with flange plate and self-drilling screw failed due to tilting and bearing. Finally, the full welding specimen is chosen as a good connection to perform the strengthening method of CFCCS section.

  8. Inflation and Bi-Axial Tensile Testing of Healthy Porcine Carotid Arteries.

    PubMed

    Boekhoven, Renate W; Peters, Mathijs F J; Rutten, Marcel C M; van Sambeek, Marc R; van de Vosse, Frans N; Lopata, Richard G P

    2016-02-01

    Knowledge of the intrinsic material properties of healthy and diseased arterial tissue components is of great importance in diagnostics. This study describes an in vitro comparison of 13 porcine carotid arteries using inflation testing combined with functional ultrasound and bi-axial tensile testing. The measured tissue behavior was described using both a linear, but geometrically non-linear, one-parameter (neo-Hookean) model and a two-parameter non-linear (Demiray) model. The shear modulus estimated using the linear model resulted in good agreement between the ultrasound and tensile testing methods, GUS = 25 ± 5.7 kPa and GTT = 23 ± 5.4 kPa. No significant correspondence was observed for the non-linear model aUS = 1.0 ± 2.7 kPa vs. aTT = 17 ± 8.8 kPa, p ∼ 0); however, the exponential parameters were in correspondence (bUS = 12 ± 4.2 vs. bTT = 10 ± 1.7, p > 0.05). Estimation of more complex models in vivo is cumbersome considering the sensitivity of the model parameters to small changes in measurement data and the absence of intraluminal pressure data, endorsing the use of a simple, linear model in vivo. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

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

    PubMed

    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.

  15. 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.

  16. 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.

  17. Analysing the optimal value for titanium implant roughness in bone attachment using a tensile test.

    PubMed

    Rønold, H J; Lyngstadaas, S P; Ellingsen, J E

    2003-11-01

    This study aims at studying the effect of surface roughness on bone attachment of coin-shaped titanium implants. All implants in this study were blasted with TiO(2) particles of 180-220 microm, and then divided into three groups. One group had no further surface treatment whereas the other two groups were subsequently etched with hot hydrochloric acid (0.01M or 1M). The surface topography of the implant specimens was examined by SEM and by a confocal laser scanner for a numeric evaluation of S(a), S(t) and S(dr). The ranging implants in the three groups differed significantly in surface structure. The implants with modified surfaces were then placed into the tibias of 12 rabbits (n=16). After 8 weeks healing, the attachment of bone to implants were examined using a standardised tensile test analysis. The implants that were only blasted (positive control) showed significantly better functional attachment (p<0.001) than the acid etched. Implant surfaces etched with 1M HCl solution had the lowest retention in bone. There was a negative correlation between the increasing roughness and mechanical retention in bone of the implants in this study. The results support observations from earlier studies that suggested an optimal surface roughness for bone attachment, identified by in situ tensile tests and expressed as the arithmetic mean deviation (S(a)), to be in the range between 3.62 and 3.90 microm and that a further attachment depended on mechanical interlocking between bone and implant.

  18. 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.

  19. 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.

  20. Glass Fiber Post/Composite Core Systems Bonded to Human Dentin: Analysis of Tensile Load vs Calculated Tensile Strength of Various Systems Using Pull-out Tests.

    PubMed

    Keul, Christine; Köhler, Patrick; Hampe, Rüdiger; Roos, Malgorzata; Stawarczyk, Bogna

    Pull-out testing was used to determine the tensile load (TL) and tensile strength (TS) of five different fiber post systems bonded to human intracanal dentin. 120 caries-free premolars, canines, and maxillary central incisors were divided into 5 different groups for 5 fiber post systems (n = 24): 1. RelyX Fiber Post 3D (RX3D); 2. RelyX Fiber Post (RX); 3. Luxa- Post (LP); 4. FibreKleer 4X Tapered Post (FK); 5. ParaPost Taper Lux (PP). The teeth were prepared and posts inserted. Core buildups were performed with the corresponding product's resin composite. All specimens were stored in water for 24 h at 37°C. TL and TS were tested on half of the specimens (n = 12/group). The remaining samples were thermocycled (10,000 x 5°C/55°C) before testing. TL was directly measured and TS was calculated using the bonding surface. Failure modes were identified using a stereomicroscope. Data were analyzed using twoway ANOVA with the post-hoc Scheffé test, as well as the chi-squared test (p < 0.05). FK and LP resulted in the lowest mean TL but were not significantly different from those of RX and RX3D. The highest mean TL and TS were observed for PP. Nevertheless, PP fell within the same statistical subset as RX3D and RX. Thermocycling showed no impact on the results. RX3D predominantly showed debonding of the post plus core buildup from the tooth; all other systems mainly demonstrated detachment of the core from the posts. PP, RX, and RX3D together with an adhesive core buildup yielded the highest bond strength to human dentin. Parameters TL and TS showed the same tendencies and statistical evidence.

  1. Effect of curing and silanizing on composite repair bond strength using an improved micro-tensile test method

    PubMed Central

    Eliasson, Sigfus Thor; Dahl, Jon E.

    2017-01-01

    Abstract Objectives: To evaluate the micro-tensile repair bond strength between aged and new composite, using silane and adhesives that were cured or left uncured when new composite was placed. Methods: Eighty Filtek Supreme XLT composite blocks and four control blocks were stored in water for two weeks and thermo-cycled. Sandpaper ground, etched and rinsed specimens were divided into two experimental groups: A, no further treatment and B, the surface was coated with bis-silane. Each group was divided into subgroups: (1) Adper Scotchbond Multi-Purpose, (2) Adper Scotchbond Multi-Purpose adhesive, (3) Adper Scotchbond Universal, (4) Clearfil SE Bond and (5) One Step Plus. For each adhesive group, the adhesive was (a) cured according to manufacturer’s instructions or (b) not cured before repair. The substrate blocks were repaired with Filtek Supreme XLT. After aging, they were serially sectioned, producing 1.1 × 1.1 mm square test rods. The rods were prepared for tensile testing and tensile strength calculated at fracture. Type of fracture was examined under microscope. Results: Leaving the adhesive uncured prior to composite repair placement increased the mean tensile values statistically significant for all adhesives tested, with or without silane pretreatment. Silane surface treatment improved significantly (p < 0.001) tensile strength values for all adhesives, both for the cured and uncured groups. The mean strength of the control composite was higher than the strongest repair strength (p < 0.001). Conclusions: Application of freshly made silane and a thin bonding layer, rendered higher tensile bond strength. Not curing the adhesive before composite placement increased the tensile bond strength. PMID:28642928

  2. Effect of curing and silanizing on composite repair bond strength using an improved micro-tensile test method.

    PubMed

    Eliasson, Sigfus Thor; Dahl, Jon E

    2017-01-01

    Objectives: To evaluate the micro-tensile repair bond strength between aged and new composite, using silane and adhesives that were cured or left uncured when new composite was placed. Methods: Eighty Filtek Supreme XLT composite blocks and four control blocks were stored in water for two weeks and thermo-cycled. Sandpaper ground, etched and rinsed specimens were divided into two experimental groups: A, no further treatment and B, the surface was coated with bis-silane. Each group was divided into subgroups: (1) Adper Scotchbond Multi-Purpose, (2) Adper Scotchbond Multi-Purpose adhesive, (3) Adper Scotchbond Universal, (4) Clearfil SE Bond and (5) One Step Plus. For each adhesive group, the adhesive was (a) cured according to manufacturer's instructions or (b) not cured before repair. The substrate blocks were repaired with Filtek Supreme XLT. After aging, they were serially sectioned, producing 1.1 × 1.1 mm square test rods. The rods were prepared for tensile testing and tensile strength calculated at fracture. Type of fracture was examined under microscope. Results: Leaving the adhesive uncured prior to composite repair placement increased the mean tensile values statistically significant for all adhesives tested, with or without silane pretreatment. Silane surface treatment improved significantly (p < 0.001) tensile strength values for all adhesives, both for the cured and uncured groups. The mean strength of the control composite was higher than the strongest repair strength (p < 0.001). Conclusions: Application of freshly made silane and a thin bonding layer, rendered higher tensile bond strength. Not curing the adhesive before composite placement increased the tensile bond strength.

  3. 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.

  4. The influence of design and production on the structural integrity of tensile test specimens and stated values for mechanical properties.

    PubMed

    Lewis, A J

    1978-06-01

    Two sizes of tensile test specimens were produced, the smaller of them by several techniques each incorporating a particular casting variable. All castings were subsequently subjected to radiographic evaluation and mechanical testing. An attempt has been made to relate the application of each variable to the degree of metal integrity produced in the specimens and ultimately to mechanical behaviour.

  5. Hyperelastic Property Measurements of Heat-Cured Silicone Adhesives by Cyclic Uniaxial Tensile Test

    NASA Astrophysics Data System (ADS)

    Li, Jue; Tarvainen, Tapio; Rich, Jaana; Turunen, Markus; Paulasto-Kröckel, Mervi

    2012-09-01

    Most of the commonly used linear elastic properties of silicone adhesives cannot precisely represent their material behavior, knowledge of which is crucial to the reliability study of electronic devices. For this reason, in this paper a widely used silicone adhesive, namely Loctite 5404, is chosen for measuring hyperelastic properties via cyclic uniaxial tensile tests. A special sample preparation procedure is developed to avoid the formation of detrimental air bubbles in the samples. Two maximum strain levels, 20% and 40%, are used in the tests. Each test includes five cyclic loadings to produce a stable stress-strain loop. Three orders of magnitude of strain rate changes are studied, and the stress-strain response of the material is found to be strain rate dependent. The measured stress-strain data are imported into Abaqus finite-element software to calibrate the material coefficients of hyperelastic material models (Mooney-Rivlin, Yeoh, Ogden, and van der Waals models). This is the first time that the hyperelastic properties of the studied silicone adhesive are presented. The determined material coefficients can be used directly in finite-element analyses and thus in reliability studies of electronic devices.

  6. Tensile test and interface retention forces between wires and composites in lingual fixed retainers.

    PubMed

    Paolone, Maria Giacinta; Kaitsas, Roberto; Obach, Patricia; Kaitsas, Vasilios; Benedicenti, Stefano; Sorrenti, Eugenio; Barberi, Fabrizio

    2015-06-01

    In daily orthodontic clinical practice retention is very important, and lingual retainers are part of this challenge. The failure of lingual retainers may be due to many factors. The aim of this study was to assess the retention forces and mechanical behavior of different types of wires matched with different kinds of composites in lingual retainers. A tensile test was performed on cylindrical composite test specimens bonded to orthodontic wires. The specimens were constructed using four different wires: a straight wire (Remanium .016×.022″ Dentaurum), two round twisted wires (Penta One .0215″ Masel, Gold Penta Twisted .0215″ Gold N'braces) and a rectangular braided wire (D-Rect .016×.022″ Ormco); and three composites: two micro-hybrids (Micro-Hybrid Enamel Plus HFO Micerium, and Micro-Hybrid SDR U Dentsply) and a micro-nano-filled composite (Micro-Nano-Filled Transbond LR 3M). The test was performed at a speed of 10mm/min on an Inström device. The wire was fixed with a clamp. The results showed that the bonding between wires and composites in lingual fixed retainers seemed to be lowest for rectangular smooth wires and increased in round twisted and rectangular twisted wires where the bonding was so strong that the maximum tension/bond strength was greater than the ultimate tensile strength of the wire. The highest values were in rectangular twisted wires. Concerning the composites, hybrid composites had the lowest interface bonding values and broke very quickly, while the nano- and micro-composites tolerated stronger forces and displayed higher bonding values. The best results were observed with the golden twisted wire and reached 21.46 MPa with the Transbond composite. With the rectangular braided wire the retention forces were so high that the Enamel Plus composite fractured when the load exceeded 154.6 N/MPa. When the same wire was combined with the Transbond LR either the wire or the composite broke when the force exceeded 240 N. The results of this

  7. 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

  8. Measurement of pressure and displacement of the membranous labyrinth in endolymphatic hydrops by the tensile test.

    PubMed

    Tanaka, M; Ishii, T; Takayama, M

    1997-01-01

    We measured the mechanical characteristics, particularly the strength of various regions of the membranous labyrinth by the penetration test with a specially designed machine. A load-displacement curve was drawn by the tensile test for the Reissner's and basement membranes. Additionally, a stress-strain curve was drawn. The modulus of elasticity was measured showing a straight line in the stress-strain curve: 1.5 x 10(2) mN/mm2 for Reissner's membrane and 9.3 x 10(2)-1.3 x 10(3) mN/mm2 for the basement membrane. Furthermore, the endolymphatic pressure was calculated at the point in time when the maximum strain as the limit of elasticity was 0.2. It was 81 Pa. The displacement of Reissner's membrane was 0.2 mm when the initial tension was taken as 0 in the formula, and that of the basement membrane was 3 to 37 microns when the initial tension was 0, 0.1, 0.2 and 0.3.

  9. 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.

  10. 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.

  11. Infrared information testing and numerical experiment analysis of the tensile necking-down phenomena of metal specimens

    NASA Astrophysics Data System (ADS)

    Wang, Laigui; Zhao, Na

    2008-11-01

    Under the action of tensile load obvious necking-down phenomena will occur in the metal test-piece. The tensile experiment about the metal test-piece has been studied, but the finite element simulation of the tensile necking-down phenomena has not been reported. The paper first studies the experiment of the mental test-piece, using the universal testing machine of WE-10A and WI-60T to load the mental test-piece and using IZ-910 infrared thermal imager to test the change process of infrared radiation temperature fields, then works out the finite element program to simulate the tensile necking-down phenomena of the metal test-piece with the elastic-plastic model. The experiment result shows that the infrared thermal effect of the metal test-piece in the process of loading is obvious, before the sample fracture will appear the omen of high temperature in the position where the future fracture will occur; in stress concentration the microcracks concentrate and the thermal figure is obvious; in the whole loading process the fracture starts from the local part, develops and evolutes gradually; with the stress change on the metal test-piece the infrared radiation temperature of the test-piece surface changes, having the temperature-rising tendency in the total and the temperature rising trend in the local fracture position is obvious. This is because the metal test-piece material or the force is uneven and the stress concentration is formed, In the position of the stress concentration the deformation destruction firstly occurs. Because the energy is released in the process of deformation destruction, so the temperature change is obvious in the fracture position. After the experiment the obvious necking-down phenomena occurs in the test-piece. At the same time, in order to provide the theoretical basis for the experiment, with the finite element software of FEPG the finite element program is worked out, with the elastic-plastic model and the uneven material the fracture

  12. Comparison of the mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile test: molecular dynamics simulation

    NASA Astrophysics Data System (ADS)

    Fazeli, Sara; Vahedpour, Morteza; Khatiboleslam Sadrnezhaad, Sayed

    2016-12-01

    Molecular dynamics simulation was used to study of mechanical properties of NiTi/Cu bilayer by nanoindentation and tensile testing. A comparison has been made among mechanical properties measured and plastic deformation process at different copper thickness during nanoindnetation and tensile test of the samples. Embedded atom method potentials for describing of inter-atomic interaction and Nose-Hoover thermostat and barostat are employed in the simulation at 400 K. The results showed that as the copper film thickness decreased, the maximum load and hardness values increased during nanoindetation. Saha and Nix model is used to describe reduced young’s modulus behaviour of the bilayer system through nanoindentation. A good agreement among calculated reduced elastic modulus by nanoindentation test and young’s modulus behaviour via tensile test have been obtained. The ‘incoherent interface’ in both of nanoindentation test and tensile testing is one of the governing factors for the dislocation propagation, which resulted in significant strengthening of the bilayer. It was observed that during tensile test, only copper layers were necked and fractured in all of samples. However, the present study seeks to examine the effect of film thickness on the free energy values that is obtained using Jarzynski’s equality during nanoindentation. As the copper film thickness was decreased, the free energy difference increased. According to both techniques, the thin film copper thickness provides lower number of nucleation locations resulting in the higher value of yield strength, hardness and free energy difference during nanoindenation. Mechanical properties of bilayer systems are improved with decreasing of copper film thickness. However, it specifies that strengths of all bilayer systems have prominent increase in young’s modulus in compared to the pure NiTi.

  13. 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.

  14. Study, by Raman Spectroscopy, of the microstructure evolution of isotactic polypropylene during tensile test and relaxation: Measuring the chains orientation

    NASA Astrophysics Data System (ADS)

    Chaudemanche, S.; Ponçot, M.; Martin, J.; Hiver, J. M.; Bourson, P.; Dahoun, A.

    2011-05-01

    This paper presents the use of a Raman spectrometer coupled to a machine VideoTraction. For uniaxial tensile mechanical testing, Raman spectra are realized, that by using spectral signatures date back to the microstructure of the material: isotactic polypropylene. Here we are particularly interested in analyzing the orientation of the chains of the crystalline phase during the elastic recovery.

  15. Micro-Tensile Testing and 3D-EBSD Characterization of Pure Nickel Multi-Crystals (Preprint)

    DTIC Science & Technology

    2011-11-01

    AFRL-RX-WP-TP-2011-4391 MICRO-TENSILE TESTING AND 3D- EBSD CHARACTERIZATION OF PURE NICKEL MULTI- CRYSTALS (Preprint) Paul A. Shade...Yoon-Suk Choi and Robert Wheeler UES Inc. NOVEMBER 2011 Approved for public release; distribution unlimited. See additional restrictions...described on inside pages STINFO COPY AIR FORCE RESEARCH LABORATORY MATERIALS AND MANUFACTURING DIRECTORATE WRIGHT-PATTERSON

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Grain Size Effect on Fracture Behavior of the Axis-Tensile Test of Inconel 718 Sheet

    NASA Astrophysics Data System (ADS)

    Liu, B. B.; Han, J. Q.; Zhao, R.; Liu, W.; Wan, M.

    2016-11-01

    Change in mechanical parts from macro-size to micro-size has become a trend in the metal- and alloy-forming process, with an increasing demand on micro-parts in the last decades. The material mechanical behaviors of micro-size parts are quite different from the conventional ones of macro-size parts due to size effect. It is necessary to further investigate the effects of grain size on material mechanisms in micro-scales, especially fracture behaviors. The fracture behaviors of Inconel 718 sheet with the thickness of 300 μm are studied by uniaxial tensile tests in different grain sizes ranging from 18 to 130 μm. The results show that fracture stress and strain decrease with the increase of grain size. A critical value in the specimen thickness (t) to grain size (d) ratio divides the strength levels into separate stages on the basis of an increase of the inverse of grain size. In addition, the grain size-dependent fracture morphology is changed in the number of dimples and micro-voids decreasing on the fracture surfaces and the sizes of micro-voids changing larger with the increase of grain size.

  1. Evaluation of the plastic yield locus for embossed sheet using biaxial tensile tests

    NASA Astrophysics Data System (ADS)

    Kim, Young-Suk; Oh, Seok-Hwan; Do, Van-Cuong; Lee, Bong-Hyun

    2016-11-01

    3D-structured (embossed) aluminium sheets have been used as heat insulation materials in automotive exhaust parts because the embossments on the sheets increase the surface area and reinforce the stiffness of exhaust components. Unlike the press-forming process for flat (non-embossed) sheets, however, that for embossed aluminium sheets is constrained by many restrictions given the distinct mechanical properties and geometric 3D shape of the latter. In designing sheet-stamping tools, manufacturers have recently used CAE technologies based on finite element analysis. Guaranteeing the effectiveness of CAE technologies necessitates information about the plastic yield criterion, which is determined primarily by performing a biaxial tensile test on cruciform-shaped specimens. We measured the yield locus of an embossed aluminium 3004-P sheet by using the camera vision method instead of strain gauge measurement because of the difficulty in attaching a strain gauge to the central region of the aluminium body. The measured yield locus of the studied sheet shows that its yield stress in equi-biaxial stress is smaller than the flat sheet yield locus measured by the strain gauge method. The shape of the yield locus of the embossed aluminium sheet also adequately corresponds with Logan-Hosford anisotropic yield function.

  2. Assessment of local vocal fold deformation characteristics in an in vitro static tensile test.

    PubMed

    Dollinger, M; Berry, D A; Huttner, B; Bohr, C

    2011-08-01

    Voice quality is strongly dependent on vocal fold dynamics, which in turn are dependent on lung pressure and vocal fold biomechanics. Numerical and physical models are often used to investigate the interactions of these different subsystems. However, the utility of numerical and physical models is limited unless appropriately validated with data from physiological models. Hence a method that enables analysis of local vocal fold deformations along the entire surface is presented. In static tensile tests, forces are applied to distinctive working points being located in cover and muscle, respectively, so that specific layer properties can be investigated. The forces are directed vertically upward and are applied along or above the vocal fold edge. The resulting deformations are analyzed using multiple perspectives and three-dimensional reconstruction. Deformation characteristics of four human vocal folds were investigated. Preliminary results showed two phases of deformation: a range with a small slope for small deformations fading into a significant nonlinear deformation trend with a high slope. An increase of tissue stiffness from posterior to anterior was detected. This trend is more significant for muscle and in the mid-anterior half of the vocal fold.

  3. 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

  4. A novel approach for preparation and in situ tensile testing of silica glass membranes in the TEM

    NASA Astrophysics Data System (ADS)

    Mačković, Mirza; Przybilla, Thomas; Dieker, Christel; Herre, Patrick; Romeis, Stefan; Stara, Hana; Schrenker, Nadine; Peukert, Wolfgang; Spiecker, Erdmann

    2017-04-01

    The mechanical behavior of glasses in the micro- and/or nanometer regime increasingly gains importance in nowadays modern technology. However, suitable small scale preparation and mechanical testing approaches for a reliable assessment of the mechanical properties of glasses still remain a big challenge. In the present work, a novel approach for site-specific preparation and quantitative in situ tensile testing of thin silica glass membranes in the transmission electron microscope is presented. Thereby, advanced focused ion beam techniques are used for the preparation of nanoscale dog bone shaped silica glass specimens suitable for in situ tensile testing. Small amounts of gallium are detected on the surface of the membranes resulting from redeposition effects during the focused ion beam preparation procedure. Possible structural changes of silica glass upon irradiation with electrons and gallium ions are investigated by controlled irradiation experiments, followed by a structural analysis using Raman spectroscopy. While moderate electron beam irradiation does not alter the structure of silica glass, ion beam irradiation results in minor densification of the silica glass membranes. In situ tensile testing of membranes under electron beam irradiation results in distinctive elongations without fracture confirming the phenomenon of superplasticity. In contrast, in situ tensile testing in the absence of the electron beam reveals an elastic/plastic deformation behavior, and finally leads to fracture of the membranes. The Young’s moduli of the glass membranes pulled at beam off conditions in the TEM are comparable with values known for bulk fused silica, while the tensile strength is in the range of values reported for silica glass fibers with comparable dimensions. The impact of electron beam irradiation on the mechanical properties of silica glass membranes is further discussed. The results of the present work open new avenues for dedicated preparation and

  5. 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.

  6. The effects of cyclic tensile and stress-relaxation tests on porcine skin.

    PubMed

    Remache, D; Caliez, M; Gratton, M; Dos Santos, S

    2017-09-11

    When a living tissue is subjected to cyclic stretching, the stress-strain curves show a shift down with the increase in the number of cycles until stabilization. This phenomenon is referred to in the literature as a preconditioning and is performed to obtain repeatable and predictable measurements. Preconditioning has been routinely performed in skin tissue tests; however, its effects on the mechanical properties of the material such as viscoelastic response, tangent modulus, sensitivity to strain rate, the stress relaxation rate, etc….remain unclear. In addition, various physical interpretations of this phenomenon have been proposed and there is no general agreement on its origin at the microscopic or mesoscopic scales. The purpose of this study was to investigate the effect of the cyclical stretching and the stress-relaxation tests on the mechanical properties of the porcine skin. Cyclic uniaxial tensile tests at large and constant strain were performed on different skin samples. The change in the reaction force, and skin's tangent modulus as a function of the number of cycles, as well as the strain rate effect on the mechanical behavior of skin samples after cycling were investigated. Stress-relaxation tests were also performed on skin samples. The change in the reaction force as a function of relaxation time and the strain rate effect on the mechanical behavior of skin samples after the stress-relaxation were investigated. The mechanical behavior of a skin sample under stress-relaxation test was modeled using a combination of hyperelasticity and viscoelasticity. Overall, the results showed that the mechanical behavior of the skin was strongly influenced by cycling and stress relaxation tests. Indeed, it was observed that the skin's resistance decreased by about half for two hours of cycling; the tangent modulus degraded by nearly 30% and skin samples became insensitive to the strain rates and accumulated progressively an inelastic deformation over time during

  7. Analysis of the coefficient of variation in shear and tensile bond strength tests.

    PubMed

    Romano, Fábio Lourenço; Ambrosano, Gláucia Maria Bovi; Magnani, Maria Beatriz Borges de Araújo; Nouer, Darcy Flávio

    2005-09-01

    The coefficient of variation is a dispersion measurement that does not depend on the unit scales, thus allowing the comparison of experimental results involving different variables. Its calculation is crucial for the adhesive experiments performed in laboratories because both precision and reliability can be verified. The aim of this study was to evaluate and to suggest a classification of the coefficient variation (CV) for in vitro experiments on shear and tensile strengths. The experiments were performed in laboratory by fifty international and national studies on adhesion materials. Statistical data allowing the estimation of the coefficient of variation was gathered from each scientific article since none of them had such a measurement previously calculated. Excel worksheet was used for organizing the data while the sample normality was tested by using Shapiro Wilk tests (alpha = 0.05) and the Statistical Analysis System software (SAS). A mean value of 6.11 (SD = 1.83) for the coefficient of variation was found by the data analysis and the data had a normal distribution (p>0.05). A range classification was proposed for the coefficient of variation from such data, that is, it should be considered low for a value lesser than 2.44; intermediate for a value between 2.44 and 7.94, high for a value between 7.94 and 9.78, and finally, very high for a value greater than 9.78. Such classification can be used as a guide for experiments on adhesion materials, thus making the planning easier as well as revealing precision and validity concerning the data.

  8. 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.

  9. 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.

  10. 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

  11. Deformation Behavior of Severely Deformed Al and Related Mechanisms Through Warm Tensile Test

    NASA Astrophysics Data System (ADS)

    Charkhesht, V.; Kazeminezhad, M.

    2017-03-01

    Flow stress and ductility behaviors of the annealed and severely deformed Al were investigated at warm deformation temperatures. Constrained groove pressing (CGP) method as a severe plastic deformation process was used. The tensile test was carried out at the temperature range of the 298-573 K and strain rate range of 0.001-0.1 s-1 to present the elevated temperature deformation behavior utilizing hyperbolic sine constitutive equation. The flow stress of the CGPed sample is increased with the number of CGP passes and decreased with temperature. Dynamic recovery and strain softening are found as main restoration mechanisms. Flow stress amounts are not remarkably affected by the strain rate. Values of the elongation are decreased with the number of CGP passes. Values of the calculated strain rate sensitivity are utilized to justify the elongation behavior. Shear bands created by CGP remarkably decrease the fracture elongation values. Temperature interval of 298-473 K cannot remarkably affect the flow stress and ductility. The interval of 473-573 K is chosen as critical temperature interval in which the values of flow stress and elongation are remarkably decreased and increased, respectively. Increasing the temperature up to 573 K causes recrystallization in shear bands. Scanning electron microscope was used to study fracture surface which can truly predict the elongation behavior. With increasing the temperature, the shear decohesion area is gradually replaced with fully dimpled structures. Finally, hot deformation activation energy for CGPed samples was calculated about 85 kJ/mol which is close to the grain boundary diffusion activation energy in pure Al.

  12. Deformation Behavior of Severely Deformed Al and Related Mechanisms Through Warm Tensile Test

    NASA Astrophysics Data System (ADS)

    Charkhesht, V.; Kazeminezhad, M.

    2017-01-01

    Flow stress and ductility behaviors of the annealed and severely deformed Al were investigated at warm deformation temperatures. Constrained groove pressing (CGP) method as a severe plastic deformation process was used. The tensile test was carried out at the temperature range of the 298-573 K and strain rate range of 0.001-0.1 s-1 to present the elevated temperature deformation behavior utilizing hyperbolic sine constitutive equation. The flow stress of the CGPed sample is increased with the number of CGP passes and decreased with temperature. Dynamic recovery and strain softening are found as main restoration mechanisms. Flow stress amounts are not remarkably affected by the strain rate. Values of the elongation are decreased with the number of CGP passes. Values of the calculated strain rate sensitivity are utilized to justify the elongation behavior. Shear bands created by CGP remarkably decrease the fracture elongation values. Temperature interval of 298-473 K cannot remarkably affect the flow stress and ductility. The interval of 473-573 K is chosen as critical temperature interval in which the values of flow stress and elongation are remarkably decreased and increased, respectively. Increasing the temperature up to 573 K causes recrystallization in shear bands. Scanning electron microscope was used to study fracture surface which can truly predict the elongation behavior. With increasing the temperature, the shear decohesion area is gradually replaced with fully dimpled structures. Finally, hot deformation activation energy for CGPed samples was calculated about 85 kJ/mol which is close to the grain boundary diffusion activation energy in pure Al.

  13. Exposure Assessment of a High-energy Tensile Test With Large Carbon Fiber Reinforced Polymer Cables.

    PubMed

    Schlagenhauf, Lukas; Kuo, Yu-Ying; Michel, Silvain; Terrasi, Giovanni; Wang, Jing

    2015-01-01

    This study investigated the particle and fiber release from two carbon fiber reinforced polymer cables that underwent high-energy tensile tests until rupture. The failing event was the source of a large amount of dust whereof a part was suspected to be containing possibly respirable fibers that could cause adverse health effects. The released fibers were suspected to migrate through small openings to the experiment control room and also to an adjacent machine hall where workers were active. To investigate the fiber release and exposure risk of the affected workers, the generated particles were measured with aerosol devices to obtain the particle size and particle concentrations. Furthermore, particles were collected on filter samples to investigate the particle shape and the fiber concentration. Three situations were monitored for the control room and the machine hall: the background concentrations, the impact of the cable failure, and the venting of the exposed rooms afterward. The results showed four important findings: The cable failure caused the release of respirable fibers with diameters below 3 μm and an average length of 13.9 μm; the released particles did migrate to the control room and to the machine hall; the measured peak fiber concentration of 0.76 fibers/cm(3) and the overall fiber concentration of 0.07 fibers/cm(3) in the control room were below the Permissible Exposure Limit (PEL) for fibers without indication of carcinogenicity; and the venting of the rooms was fast and effective. Even though respirable fibers were released, the low fiber concentration and effective venting indicated that the suspected health risks from the experiment on the affected workers was low. However, the effect of long-term exposure is not known therefore additional control measures are recommended.

  14. 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.

  15. Bonding characteristics in NiAl intermetallics with O impurity: a first-principles computational tensile test.

    PubMed

    Hu, Xue-Lan; Zhang, Ying; Lu, Guang-Hong; Wang, Tianmin

    2009-01-14

    We have performed a first-principles computational tensile test on NiAl intermetallics with O impurity along the [001] crystalline direction on the (110) plane to investigate the tensile strength and the bonding characteristics of the NiAl-O system. We show that the ideal tensile strength is largely reduced due to the presence of O impurity in comparison with pure NiAl. The investigations of the atomic configuration and bond-length evolution show that O prefers to bond with Al, forming an O-Al cluster finally with the break of O-Ni bonds. The O-Ni bonds are demonstrated to be weaker than the O-Al bonds, and the reduced tensile strength originates from such weaker O-Ni bonds. A void-like structure forms after the break of the O-Ni and some Ni-Al bonds. Such a void-like structure can act as the initial nucleation or the propagation path of the crack, and thus produce large effects on the mechanical properties of NiAl.

  16. 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

  17. Grips for Lightweight Tensile Specimens

    NASA Technical Reports Server (NTRS)

    Witte, William G., Jr.; Gibson, Walter D.

    1987-01-01

    Set of grips developed for tensile testing of lightweight composite materials. Double-wedge design substantially increases gripping force and reduces slippage. Specimen held by grips made of hardened wedges. Assembly screwed into load cell in tensile-testing machine.

  18. Revision of the tensile database for V-Ti and V-Cr-Ti alloys tested at ANL.

    SciTech Connect

    Billone, M. C.

    1998-01-13

    The published database for the tensile properties of unirradiated and irradiated vanadium-based alloys tested at Argonne National Laboratory (ANL) has been reviewed. The alloys tested are in the ranges of V-(0-18)wt.%Ti and V-(4-15)wt.%Cr-(3-15)wt.%Ti. A consistent methodology, based on ASTM terminology and standards, has been used to re-analyze the unpublished load vs. displacement curves for 162 unirradiated samples and 91 irradiated samples to determine revised values for yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE) and total elongation (TE). The revised data set contains lower values for UE ({minus}5{+-}2% strain) and TE ({minus}4{+-}2% strain) than previously reported. Revised values for YS and UTS are consistent with the previously-published values in that they are within the scatter usually associated with these properties.

  19. Mechanical and Linear Viscoelastic Properties of High Density Polyethylene Obtained from Tensile and Dead-Load Creep Tests

    DTIC Science & Technology

    1990-06-01

    from virgin pellets. Table 1. CHEMICAL ANALYSIS OF THREE GRADES OF HIGH DENSITY POLYETHYLENE Molecular Weight Mw Mn Melt Weight Number Flow HLMI...SECURITM CLASSIFICATON OF THIS PAGE (When Data Entered) Block No. 20 ABSTRACT Three grades of high density polyethylene ( HDPE ) are tested for tensile...66 Company’s materials literature, along with melt - flow index values, are tabulated in Table I along with our values obtained from the gel per

  20. 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.

  1. 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.

  2. 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.

  3. The NanoBeamBalance: A passive, tensile-test device for the atomic force microscope

    NASA Astrophysics Data System (ADS)

    Wenger, M. P. E.; Mesquida, P.

    2011-05-01

    An add-on device is presented, which significantly expands the force measurement capabilities of the atomic force microscope (AFM). The device consists of a completely passive mechanism, which translates the vertical motion of the AFM tip in force measurements into a horizontal motion of two sample support pads. The advantage is that it is much easier to deposit microscopic samples from suspension onto flat surfaces than to attach them reliably between tip and a surface. The working-principle and the design of the device is comprehensively described and demonstrated on the example of collagen fibres with a diameter of a few μm. Well-defined tensile measurements in longitudinal direction were performed, showing that the tensile stiffness of collagen fibres from rat tail tendon decreases by a factor of 5 when rehydrated from a dried sample and slowly increases upon cross-linking with glutaraldehyde.

  4. The NanoBeamBalance: a passive, tensile-test device for the atomic force microscope.

    PubMed

    Wenger, M P E; Mesquida, P

    2011-05-01

    An add-on device is presented, which significantly expands the force measurement capabilities of the atomic force microscope (AFM). The device consists of a completely passive mechanism, which translates the vertical motion of the AFM tip in force measurements into a horizontal motion of two sample support pads. The advantage is that it is much easier to deposit microscopic samples from suspension onto flat surfaces than to attach them reliably between tip and a surface. The working-principle and the design of the device is comprehensively described and demonstrated on the example of collagen fibres with a diameter of a few μm. Well-defined tensile measurements in longitudinal direction were performed, showing that the tensile stiffness of collagen fibres from rat tail tendon decreases by a factor of 5 when rehydrated from a dried sample and slowly increases upon cross-linking with glutaraldehyde.

  5. 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.

  6. 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.

  7. 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.

  8. Serration Phenomena Occurring During Tensile Tests of Three High-Manganese Twinning-Induced Plasticity (TWIP) Steels

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin; Shin, Sang Yong; Lee, Junghoon; Ahn, Dong-Hyun; Kim, Hyoung Seop; Kim, Sung-Kyu; Chin, Kwang-Geun; Lee, Sunghak

    2014-02-01

    In this study, the serration phenomena of two high-Mn TWIP steels and an Al-added TWIP steel were examined by tensile tests, and were explained by the microstructural evolution including formation of localized Portevin-Le Chatelier deformation bands and twins. In stress-strain curves of the high-Mn steels, serrations started in a fine and short shape, and their height and periodic interval increased with increasing strain, whereas the Al-added steel did not show any serrations. According to digital images of strain rate and strain obtained from a vision strain gage system, deformation bands were initially formed at the upper region of the gage section, and moved downward along the tensile loading direction. The time when the band formation started was matched with the time when one serration occurred in the stress-time curve. This serration behavior was generally explained by dynamic strain aging, which was closely related with the formation of deformation bands.

  9. 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.

  10. 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.

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

    PubMed

    Sivaraj, Aravind

    2013-06-01

    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. 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. 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.

  12. 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

  13. 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.

  14. Stiffness and strength of fracture callus. Relative rates of mechanical maturation as evaluated by a uniaxial tensile test.

    PubMed

    Black, J; Perdigon, P; Brown, N; Pollack, S R

    1984-01-01

    Mechanical evaluation of healing fractures in rabbits suggests that tensile testing both minimizes artifacts and permits direct intrinsic determinations of tissue quality. In healing osteotomies in the rabbit fibula, there is a rapid return of stiffness at 16 days, correlating with callus maturation. The failure mode proved to be a "delamination" fracture. Values for the strength of bone (3.3 N/m2) and fibrocartilage (0.2 N/m2) correlate well with the results of other studies but are probably values of maximum tissue adhesion strength.

  15. 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.

  16. Micro-tensile bond testing of resin cements to dentin and an indirect resin composite.

    PubMed

    Mak, Yiu-Fai; Lai, Shirley C N; Cheung, Gary S P; Chan, Alex W K; Tay, Franklin R; Pashley, David H

    2002-12-01

    Micro-tensile bond strength (microTBS) evaluation and fractographic analysis were used to compare four resin cement systems (AC: All-Bond 2/Choice; RX: Single Bond/RelyX ARC; SB: Super-Bond C & B; and PF: Panavia F) in indirect composite/dentin adhesive joints. Flat dentin surfaces were created on extracted human third molars. The resin cements were used according to the manufacturers' instructions for bonding silanized composite overlays to deep coronal dentin. 0.9x0.9 composite-dentin beams prepared from the luted specimens were stressed to failure in tension. Dentin sides of all fractured specimens were examined by scanning electron microscopy (SEM) to examine the failure modes. In group PF, morphologic features that could not be resolved at the SEM level were further validated by transmission electron microscopy (TEM) examination of the SEM specimens. Statistical analyses revealed significant difference (p<0.05) among microTBS and failure modes in the resin cement groups. The two groups (AC and RX) with highest microTBS failed predominantly along the composite overlay/cement interface. Cohesive failure in resin cement was primarily observed in group SB that exhibited intermediate microTBS values. In group PF with the lowest microTBS, failure occurred mostly along the dentin surface. Globular resin agglomerates seen by SEM on PF-treated dentin were distinguished from silica fillers by TEM. The bond between the processed composite and the luting resin cement was the weak link in indirect composite restorations cemented with AC or RX. Super-Bond C&B exhibited intermediate tensile strength and Panavia F is less reliable when used in conjunction with a self-etching primer for bonding indirect restorations to dentin.

  17. Estimation of uncertainty with the modulus of elasticity measured by means of tensile test for BSCCO tapes

    NASA Astrophysics Data System (ADS)

    Osamura, Kozo; Nyilas, Arman; Shin, H.

    2010-10-01

    The international round robin test (RRT) was conducted in order to establish the international standard for the tensile test method for BSCCO-2223 tape shaped wires. The measurands of mechanical properties were statistically analyzed to estimate their standard uncertainties and their correlation among laboratories. Consequently the large variance was observed with the modulus of elasticity determined from the initial loading curve. The reason has been examined by estimating type B uncertainties causing at every step of the experimental procedure. With respect to the modulus of elasticity, the grand intra-lab average of relative standard uncertainty (RSU) obtained from the RRT coincided roughly with that derived by means of type B evaluation. Thus it is emphasized that the type B evaluation is very effective tool for expecting the uncertainties of the observations like the modulus of elasticity. On the other hand, the grand over-all RSU was larger than the grand intra-lab one. The combined standard uncertainties were calculated by changing the strain rate, but kept other parameters constant. In order to suppress the influence from the strain rate to the variance, it has been recommended that the strain rate shall be regulated less than 2 × 10 -4 1/s in the tensile test method.

  18. 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

  19. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. 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.

    2016-11-01

    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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Influence of static tensile testing on the deformation behavior of Al-4% Cu alloy containing micro- and nanoparticles

    NASA Astrophysics Data System (ADS)

    Khrustalyov, Anton; Vorozhtov, Sergey; Kulkov, Sergey

    2016-11-01

    At present, aluminum alloys reinforced with nonmetallic particles are of great interest in various fields of science and technology due to their high specific strength, hardness, wear resistance, and other properties. At the same time there is a great interest in the study of processes occurring during plastic deformation of such materials under static tensile loading. Plastic flow of metals occurs through the creation and movement of linear defects (dislocations), in which there is a phenomenon of discontinuous yielding. An introduction of particles into aluminum alloy promotes a considerable increase of stiffness and specific strength of alloys, and the study of the deformation behavior of such alloys is of great interest. The objective of this research is to analyze mechanical properties and the deformation behavior of aluminum alloy with the identification of mechanisms of plastic deformation when introducing solid nonmetallic micro- and nanoparticles into the soft aluminum matrix. An analysis of the microstructure of the obtained alloys shows that the introduction of particles (Al2O3, TiB2, TiC) leads to a reduction of the alloy grain size from 350 to 170 µm while residual porosity does not exceed 2%. Tensile tests performed show that the change in the type and quantity of particles also changes characteristics of discontinuous yielding, thus resulting in an increase of yield strength (from 18 to 40 MPa), reduction of ductility (from 15 to 2%), and moreover a significant increase of tensile strength (from 77 to 130 MPa), as compared to the initial Al-4 wt % Cu alloy.

  8. In vivo mechanical properties of thoracic aortic aneurysmal wall estimated from in vitro biaxial tensile test.

    PubMed

    Fukui, Tomohiro; Matsumoto, Takeo; Tanaka, Toshihiro; Ohashi, Toshiro; Kumagai, Kiichiro; Akimoto, Hiroji; Tabayashi, Koichi; Sato, Masaaki

    2005-01-01

    To investigate the mechanism of aneurysm rupture, it is necessary to examine the mechanical properties of aneurysm tissues in vivo. A new approach to evaluate in vivo mechanical properties of aortic aneurysmal tissues has been proposed in this study. The shape of the aneurysm was modeled as a sphere, and equi-biaxial stress in the in vivo state was estimated from the diameter and the wall thickness of each aneurysm and mean blood pressure of each patient. The mechanical properties of the aneurysm at the in vivo stress were estimated from its in vitro biaxial tensile properties. There were no significant correlations among maximum diameter D, wall thickness t, and mean infinitesimal strain in the in vivo state epsilon(m). This indicates the wall deformation during aneurysm development was not elastic but plastic. The mean incremental elastic modulus H(m), an index of tissue stiffness, had a significant positive correlation with elastic modulus anisotropy index K(H). This indicates the aneurysmal wall got more anisotropic in vivo as it becomes stiffer.

  9. Viscoelastic properties and residual strain in a tensile creep test on bovine temporomandibular articular discs.

    PubMed

    Tanaka, E; Tanaka, M; Aoyama, J; Watanabe, M; Hattori, Y; Asai, D; Iwabe, T; Sasaki, A; Sugiyama, M; Tanne, K

    2002-02-01

    This study was designed to evaluate the creep characteristics and residual strain of bovine temporomandibular joint (TMJ) discs in tension. Twenty discs were divided into three specimens each: central, lateral and medial regions. Tension of 1.0 MPa was applied and sustained for 20 min to the specimens from 10 right-side discs, and tension of 1.5 MPa to specimens from 10 left-side discs. After the period of tension for creep, the specimens were removed from the tension devices and restoration observed for 20 min. Time-dependent creep curves showed a marked change in strain during the initial 5s. The essential time delay in strain ceased after 2 min, and strain reached an almost steady level after 3 min. At a tensile stress of 1.5 MPa, a strain of 14.5% on average was produced after 20 min creep in the central specimens; peripheral specimens showed strains of 12.4% on average. There were significant differences in strain between the central and peripheral specimens. The residual strain after 20 min restoration was 0.93% on average and there were no significant regional differences. This creep feature could be well represented by a generalized linear viscoelastic model. It was concluded that the regional differences in viscoelasticity might be caused by the complicated articulating functions of the TMJ, and that the residual strain caused by sustained stress could be an important factor in disc deformation.

  10. [Aging effect on mechanical properties in fluid resin. (Part 3) Affection of residual monomer on the surface morphology after tensile test by microscopic observation (author's transl)].

    PubMed

    Horiuchi, A

    1981-04-01

    Affection of residual monomer on the surface morphology after tensile test was observed by an scanning microscope. Evaporation or leaching of the monomer gave big influence on the morphology of pearls and matrix. The observation suggested that the residual monomer existed mainly in the matrix. When the residual monomer disappeared, the surface morphology did not change by tensile load. It is the most important point to get good denture with fluid resin that we could decrease the residual monomer as possible.

  11. 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.

  12. The evaluation of ordinary Portland cement concrete subject to elevated temperatures in conjunction with acoustic emission and splitting tensile test

    NASA Astrophysics Data System (ADS)

    Su, Yu-Min; Hou, Tsung-Chin; Chen, Guan-Ying; Hou, Ping-Ni

    2017-04-01

    The research objective was to evaluate Ordinary Portland Cement concrete subject to various elevated temperatures. Single OPC concrete mixture with water to cementitious (w/c) equal to 0.45 was proportioned. Concrete specimens were cast and placed in the curing tank in which water was saturated with calcium hydroxide. After ninety days of moist-cure, three elevated temperatures, namely 300, 600, and 900-°C, were carried out upon hardened concrete specimens. Furthermore, two post-damaged curing conditions were executed to recover damaged concrete specimens: one was to recure under 23°C with 50% humidity in a controlled environmental chamber and the other was to recure in the same curing tank. Acoustic emission apparatus coupled with the splitting tensile test was utilized and found able to assess damaged concrete. Before concrete subject to elevated temperatures, the development of indirect tensile strength versus displacement diagram fit well with the tendency of AE energy release. It was found there was a large amount of AE energy released when stress and displacement diagram developed about 40-50%. As such could be identified as the onset of first fracture and the plain concrete generally exhibited a quasi-brittle fracture with two major series of AE energy dissipations; however when concrete specimens were subject to elevated temperatures, the damaged concrete specimens displayed neither fracture pattern nor the "double-hump" AE energy dissipation in comparison with those of plain concrete.

  13. Semi-analytical and Numerical Studies on the Flattened Brazilian Splitting Test Used for Measuring the Indirect Tensile Strength of Rocks

    NASA Astrophysics Data System (ADS)

    Huang, Y. G.; Wang, L. G.; Lu, Y. L.; Chen, J. R.; Zhang, J. H.

    2015-09-01

    Based on the two-dimensional elasticity theory, this study established a mechanical model under chordally opposing distributed compressive loads, in order to perfect the theoretical foundation of the flattened Brazilian splitting test used for measuring the indirect tensile strength of rocks. The stress superposition method was used to obtain the approximate analytic solutions of stress components inside the flattened Brazilian disk. These analytic solutions were then verified through a comparison with the numerical results of the finite element method (FEM). Based on the theoretical derivation, this research carried out a contrastive study on the effect of the flattened loading angles on the stress value and stress concentration degree inside the disk. The results showed that the stress concentration degree near the loading point and the ratio of compressive/tensile stress inside the disk dramatically decreased as the flattened loading angle increased, avoiding the crushing failure near-loading point of Brazilian disk specimens. However, only the tensile stress value and the tensile region were slightly reduced with the increase of the flattened loading angle. Furthermore, this study found that the optimal flattened loading angle was 20°-30°; flattened load angles that were too large or too small made it difficult to guarantee the central tensile splitting failure principle of the Brazilian splitting test. According to the Griffith strength failure criterion, the calculative formula of the indirect tensile strength of rocks was derived theoretically. This study obtained a theoretical indirect tensile strength that closely coincided with existing and experimental results. Finally, this paper simulated the fracture evolution process of rocks under different loading angles through the use of the finite element numerical software ANSYS. The modeling results showed that the Flattened Brazilian Splitting Test using the optimal loading angle could guarantee the tensile

  14. 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.

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

    PubMed

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

    2014-10-15

    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.

  16. 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.

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

    DTIC Science & Technology

    1975-08-01

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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Mechanical behavior and failure analysis of prosthetic retaining screws after long-term use in vivo. Part 3: Preload and tensile fracture load testing.

    PubMed

    Al Jabbari, Youssef S; Fournelle, Raymond; Ziebert, Gerald; Toth, Jeffrey; Iacopino, Anthony M

    2008-04-01

    The aim of this study was to determine the preload and tensile fracture load values of prosthetic retaining screws after long-term use in vivo compared to unused screws (controls). Additionally, the investigation addressed whether the preload and fracture load values of prosthetic retaining screws reported by the manufacturer become altered after long-term use in vivo. For preload testing, 10 new screws (controls) from Nobel Biocare (NB) and 73 used retaining screws [58 from NB and 15 from Sterngold (SG)] were subjected to preload testing. For tensile testing, eight controls from NB and 58 used retaining screws (46 from NB and 12 from SG) were subjected to tensile testing. Used screws for both tests were in service for 18-120 months. A custom load frame, load cell, and torque wrench setup were used for preload testing. All 83 prosthetic screws were torqued once to 10 Ncm, and the produced preload value was recorded (N) using an X-Y plotter. Tensile testing was performed on a universal testing machine and the resulting tensile fracture load value was recorded (N). Preload and tensile fracture load values were analyzed with 2-way ANOVA and Tukey post-hoc tests. There was a significant difference between preload values for screws from NB and screws from SG (p < 0.001). The preload values for gold alloy screws from NB decreased as the number of years in service increased. There was a significant difference between tensile fracture values for the three groups (gold alloy screws from NB and SG and palladium alloy screws from NB) at p < 0.001. The tensile fracture values for gold alloy screws from NB and SG decreased as the number of years in service increased. In fixed detachable hybrid prostheses, perhaps as a result of galling, the intended preload values of prosthetic retaining screws may decrease with increased in-service time. The reduction of the fracture load value may be related to the increase of in-service time; however, the actual determination of this

  3. 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.

  4. 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.

  5. 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).

  6. 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).

  7. 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).

  8. 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).

  9. [Relationship between mechanical properties and amounts of casting porosities in tensile-test fracture surface of Au-Pd-Ag-Cu alloy (author's transl)].

    PubMed

    Ohno, H; Miyakawa, O; Watanabe, K; Siokawa, N

    1978-04-01

    One hundred and thirty-nine tensile-test specimens of Au-Pd-Ag-Cu alloy were cast in various casting conditions. The specimens were subjected age-hardening heat-treatment. The casting porosities and the nonmetallic inclusions in the surface of a tensile-test fracture of cast specimens were observed and analyzed by use of Electron Probe X-ray Microanalyzer (EPMA). The polosity ratio that is the area ratio of the porosities to the fracture surface was determined. Studies were quantitatively made on the effect of the porosity ratio on the tensile strength and the elongation. Furthermore, the effect of the casting conditions on the tensile strength was investigated. The main results were summarized as follows; The tensile strength decreased only slightly within about 15% of the porosity ratio and remarkably with an increase in its ratio in the range from about 15% to 50%. The elongation, however, decreased considerably in the presence of the porosities of only a few per cent. Aspects of the decrease curves on the tensile strength and the elongation were represented in the shape of an inverse S-type and hyperbolic curve with an increase in the porosity ratio, respectively. With an increase in the porosity ratio, the shapes of the tensile-test specimens at the fracture part and load-elongation curves in the tensile-tests were shown as a brittle fracture. However, the result observed by a scanning electron microscope revealed that the fracture surfaces without the porosities showed mostly "dimple pattern" suggesting a characteristic figure of a ductile fracture. The nonmetallic inclusions in the fracture surfaces were identified as SiO2 (quartz) which was derived from an ingredient of an investment by comparing the inclusion with the reference standards on the characteristic X-ray O Kalpha spectra by EPMA. The microstructures observed by a light microscope showed a coarse structure with the high temperature casting conditions. However, the results of a scanning

  10. 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.

  11. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Simulating plastic surgery: from human skin tensile tests, through hyperelastic finite element models to real-time haptics.

    PubMed

    Lapeer, R J; Gasson, P D; Karri, V

    2010-12-01

    In this paper, we provide a summary of a number of experiments we conducted to arrive at a prototype real-time simulator for plastic surgical interventions such as skin flap repair and inguinal herniotomy. We started our research with a series of in-vitro tensile stress tests on human skin, harvested from female patients undergoing plastic reconstructive surgery. We then used the acquired stress-strain data to fit hyperelastic models. Three models were considered: General Polynomial, Reduced Polynomial and Ogden. Only Reduced Polynomial models were found to be stable, hence they progressed to the next stage to be used in an explicit finite element model aimed at real-time performance in conjunction with a haptic feedback device. A total Lagrangian formulation with the half-step central difference method was employed to integrate the dynamic equation of motion of the mesh. The mesh was integrated into two versions of a real-time skin simulator: a single-threaded version running on a computer's main central processing unit and a multi-threaded version running on the computer's graphics card. The latter was achieved by exploiting recent advances in programmable graphics technology.

  13. 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.

  14. 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.

  15. Extreme Cold Testing of High Performance Fabric Materials: Gelbo Flex, Tensile Strength, and UV Exposure Test Results

    DTIC Science & Technology

    2014-07-01

    designed for the containment and transport of bulk-waste products in more temperate climates and required evaluation and testing to determine whether or...behavior at both room temperature and at −40°C. It was vital to determine if the failure mode changed from an elastic-plastic deformation at room...for Testing and Materials. Bernhard, G., C. R. Booth, and J. C. Ehramjian. 2008. Comparison of UV irradiance measurements at Summit, Greenland

  16. 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%.

  17. Comparison and ranking of superelasticity of different austenite active nickel-titanium orthodontic archwires using mechanical tensile testing and correlating with its electrical resistivity.

    PubMed

    Nagarajan, D; Baskaranarayanan, Balashanmugam; Usha, K; Jayanthi, M S; Vijjaykanth, M

    2016-10-01

    The application of light and continuous forces for optimum physiological response and the least damage to the tooth supporting structures should be the primary aim of an orthodontist. Nickel-titanium (NiTi) alloys with their desirable properties are one of the natural choices of the clinicians. This study was aimed to compare and rank them based on its tensile strength and electrical resistivity. The sample consisted of eight groups of 0.017 inch × 0.025 inch rectangular archwires from eight different manufacturers, and five samples from each group for tensile testing and nine samples for electrical resistivity tests were used. Data for stress at 10% strain and the initial slope were statistically analyzed with an analysis of variance and Scheffe tests with P < 0.05. The stress/strain plots of each product were ranked for superelastic behavior. The rankings of the wires tested were based primarily on the unloading curve's slope which is indicative of the magnitude of the deactivation force and secondarily on the length of the horizontal segment which is indicative of continuous forces during deactivation. For calculating the electric resistivity, the change in resistance after inducing strain in the wires was taken into account for the calculation of degree of martensite transformation and for ranking. In tensile testing Ortho Organizers wires ranked first and GAC Lowland NiTi wires ranked last. For resistivity tests Ormco A wires were found superior and Morelli remained last. these rankings should be correlated clinically and need further studies.

  18. 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.

  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. Evaluation of the histological and mechanical features of tendon healing in a rabbit model with the use of second-harmonic-generation imaging and tensile testing

    PubMed Central

    Hase, E.; Sato, K.; Yonekura, D.; Minamikawa, T.; Takahashi, M.

    2016-01-01

    Objectives This study aimed to evaluate the histological and mechanical features of tendon healing in a rabbit model with second-harmonic-generation (SHG) imaging and tensile testing. Materials and Methods A total of eight male Japanese white rabbits were used for this study. The flexor digitorum tendons in their right leg were sharply transected, and then were repaired by intratendinous stitching. At four weeks post-operatively, the rabbits were killed and the flexor digitorum tendons in both right and left legs were excised and used as specimens for tendon healing (n = 8) and control (n = 8), respectively. Each specimen was examined by SHG imaging, followed by tensile testing, and the results of the two testing modalities were assessed for correlation. Results While the SHG light intensity of the healing tendon samples was significantly lower than that of the uninjured tendon samples, 2D Fourier transform SHG images showed a clear difference in collagen fibre structure between the uninjured and the healing samples, and among the healing samples. The mean intensity of the SHG image showed a moderate correlation (R2 = 0.37) with Young’s modulus obtained from the tensile testing. Conclusion Our results indicate that SHG microscopy may be a potential indicator of tendon healing. Cite this article: E. Hase, K. Sato, D. Yonekura, T. Minamikawa, M. Takahashi, T. Yasui. Evaluation of the histological and mechanical features of tendon healing in a rabbit model with the use of second-harmonic-generation imaging and tensile testing. Bone Joint Res 2016;5:577–585. DOI: 10.1302/2046-3758.511.BJR-2016-0162.R1. PMID:27881441

  1. 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.

  2. 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.

  3. 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.

  4. Investigation of the elastic modulus, tensile and flexural strength of five skull simulant materials for impact testing of a forensic skin/skull/brain model.

    PubMed

    Falland-Cheung, Lisa; Waddell, J Neil; Chun Li, Kai; Tong, Darryl; Brunton, Paul

    2017-04-01

    Conducting in vitro research for forensic, impact and injury simulation modelling generally involves the use of a skull simulant with mechanical properties similar to those found in the human skull. For this study epoxy resin, fibre filled epoxy resin, 3D-printing filaments (PETG, PLA) and self-cure acrylic denture base resin were used to fabricate the specimens (n=20 per material group), according to ISO 527-2 IBB and ISO20795-1. Tensile and flexural testing in a universal testing machine was used to measure their tensile/flexural elastic modulus and strength. The results showed that the epoxy resin and fibre filled epoxy resin had similar tensile elastic moduli (no statistical significant difference) with lower values observed for the other materials. The fibre filled epoxy resin had a considerably higher flexural elastic modulus and strength, possibly attributed to the presence of fibres. Of the simulants tested, epoxy resin had an elastic modulus and flexural strength close to that of mean human skull values reported in the literature, and thus can be considered as a suitable skull simulant for a skin/skull/brain model for lower impact forces that do not exceed the fracture stress. For higher impact forces a 3D printing filament (PLA) may be a more suitable skull simulant material, due to its closer match to fracture stresses found in human skull bone. Influencing factors were also anisotropy, heterogeneity and viscoelasticity of human skull bone and simulant specimens.

  5. Comparison of the direct burst pressure and the ring tensile test methods for mechanical characterization of tissue-engineered vascular substitutes.

    PubMed

    Laterreur, Véronique; Ruel, Jean; Auger, François A; Vallières, Karine; Tremblay, Catherine; Lacroix, Dan; Tondreau, Maxime; Bourget, Jean-Michel; Germain, Lucie

    2014-06-01

    Tissue engineering provides a promising alternative for small diameter vascular grafts, especially with the self-assembly method. It is crucial that these grafts possess mechanical properties that allow them to withstand physiological flow and pressure without being damaged. Therefore, an accurate assessment of their mechanical properties, especially the burst pressure, is essential prior to clinical release. In this study, the burst pressure of self-assembled tissue-engineered vascular substitutes was first measured by the direct method, which consists in pressurizing the construct with fluid until tissue failure. It was then compared to the burst pressure estimated by Laplace׳s law using data from a ring tensile test. The major advantage of this last method is that it requires a significantly smaller tissue sample. However, it has been reported as overestimating the burst pressure compared to a direct measurement. In the present report, it was found that an accurate estimation of the burst pressure may be obtained from a ring tensile test when failure internal diameter is used as the diameter parameter in Laplace׳s law. Overestimation occurs with the method previously reported, i.e. when the unloaded internal diameter is used for calculations. The estimation of other mechanical properties was also investigated. It was demonstrated that data from a ring tensile test provide an accurate estimate of the failure strain and the stiffness of the constructs when compared to measurements with the direct method. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. 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.

  7. Comparison and ranking of superelasticity of different austenite active nickel-titanium orthodontic archwires using mechanical tensile testing and correlating with its electrical resistivity

    PubMed Central

    Nagarajan, D.; Baskaranarayanan, Balashanmugam; Usha, K.; Jayanthi, M. S.; Vijjaykanth, M.

    2016-01-01

    Introduction: The application of light and continuous forces for optimum physiological response and the least damage to the tooth supporting structures should be the primary aim of an orthodontist. Nickel-titanium (NiTi) alloys with their desirable properties are one of the natural choices of the clinicians. Aim: This study was aimed to compare and rank them based on its tensile strength and electrical resistivity. Materials and Methods: The sample consisted of eight groups of 0.017 inch × 0.025 inch rectangular archwires from eight different manufacturers, and five samples from each group for tensile testing and nine samples for electrical resistivity tests were used. Data for stress at 10% strain and the initial slope were statistically analyzed with an analysis of variance and Scheffe tests with P < 0.05. The stress/strain plots of each product were ranked for superelastic behavior. The rankings of the wires tested were based primarily on the unloading curve's slope which is indicative of the magnitude of the deactivation force and secondarily on the length of the horizontal segment which is indicative of continuous forces during deactivation. For calculating the electric resistivity, the change in resistance after inducing strain in the wires was taken into account for the calculation of degree of martensite transformation and for ranking. Results: In tensile testing Ortho Organizers wires ranked first and GAC Lowland NiTi wires ranked last. For resistivity tests Ormco A wires were found superior and Morelli remained last. Conclusion: these rankings should be correlated clinically and need further studies. PMID:27829751

  8. Characterization of fracture behavior of human atherosclerotic fibrous caps using a miniature single edge notched tensile test.

    PubMed

    Davis, Lindsey A; Stewart, Samantha E; Carsten, Christopher G; Snyder, Bruce A; Sutton, Michael A; Lessner, Susan M

    2016-10-01

    One well-established cause of ischemic stroke is atherosclerotic plaque rupture in the carotid artery. Rupture occurs when a tear in the fibrous cap exposes highly thrombogenic material in the lipid core. Though some fibrous cap material properties have been measured, such as ultimate tensile strength and stress-strain responses, there has been very little, if any, data published regarding the fracture behavior of atherosclerotic fibrous caps. This study aims to characterize the qualitative and quantitative fracture behavior of human atherosclerotic plaque tissue obtained from carotid endarterectomy samples using two different metrics. Uniaxial tensile experiments along with miniature single edge notched tensile (MSENT) experiments were performed on strips of isolated fibrous cap. Crack tip opening displacement (CTOD) and stress in the un-cracked segment (UCS) were measured at failure in fibrous cap MSENT specimens subjected to uniaxial tensile loading. Both CTOD and the degree of crack blunting, measured as the radius of curvature of the crack tip, increased as tearing propagated through the tissue. Higher initial stress in the UCS is significantly correlated with higher collagen content and lower macrophage content in the fibrous cap (ρ=0.77, P=0.009; ρ=-0.64, P=0.047; respectively). Trends in the data show that higher CTOD is inversely related to collagen content, though the sample size in this study is insufficient to statistically substantiate this relationship. To the authors' knowledge, this is the pioneering study examining the fracture behavior of fibrous caps and the first use of the CTOD metric in vascular tissue. A tear in the fibrous cap of atherosclerotic plaque can lead to ischemic stroke or myocardial infarction. While there is some information in the literature regarding quantitative measures of fibrous cap failure, there is little information regarding the behavior of the tissue during failure. This study examines the failure behavior of fibrous

  9. 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.

  10. 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.

  11. 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.

  12. 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).

  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

    2011-04-01

    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.

  14. Effects of Changes in Test Temperature on Tensile Properties and Notched Vs Fatigue Precracked Toughness of a Zr-Based BMG Composite

    NASA Astrophysics Data System (ADS)

    Clinton, Jessica A.; Morrison, Rachel L.; Carter, Jennifer L. W.

    2017-07-01

    Tensile and fracture toughness behavior of a Zr-based bulk metallic glass matrix composite (BMGMC) containing a body-centered cubic crystalline phase was examined over temperatures from 77 K to 653 K (-196 °C to 380 °C). The BMGMC exhibited tensile plasticity at all test temperatures. The sample tested in tension at 173 K (-100 °C) exhibited work hardening but the remaining samples tested at higher temperatures exhibited work softening. EBSD analysis of the crystalline phase after tensile testing provides insight into active deformation mechanisms in the crystalline phase. At 603 K (330 °C), the dendrites exhibit significant plastic strain, with the dendrites oriented {101} parallel to the loading direction exhibiting the least amount of strain. Schmid factor analysis leads to the hypothesis that {110}<111> dislocation mechanisms are active at this temperature. Additionally, measurements of dendrite shape as a function of macroscopic strain state in the tension experiments provide insight into cooperative deformation mechanisms in the composite. At low temperatures, the fracture toughness of the notch toughness samples exceeded that of fatigue precracked samples; but at and above room temperature, the toughness values of notched and fatigue precracked samples converge. These observations are rationalized based on the changes to the flow and fracture behavior of the glass and the crystalline phases over this temperature range. At low temperatures, the crystalline phase is sensitive to defects and changes in stress state that reduce its energy absorbing ability. At higher temperatures, both constituents possess lower strength and are less sensitive to defects, enabling more significant crack tip blunting in the fatigue precracked samples. This produces toughness values that are similar to those obtained for the notched samples.

  15. 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.

  16. 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.

  17. Modeling of the stress-strain behaviour during monotonic and cyclic tensile testing of unidirectional SiC-fibre reinforced BMAS glass-ceramic composites

    SciTech Connect

    Vanswijgenhoven, E.; Wevers, M.; Van Der Biest, O.

    1995-12-01

    A model is proposed which gives a complete description of the stress-strain behaviour during monotonic and cyclic tensile testing of unidirectional SiC-fibre toughened BMAS glass-ceramic matrix composites using parameters describing the microstructure, the micromechanical behaviour, the damage development in matrix and fibre and the residual stress state as input. The model reproduces the main features of the stress-strain behaviour of the material and is versatile enough to take different damage development sequences and residual stress states into account. Furthermore, it offers the possibility to evaluate the impact of changes in microstructure and micromechanical behaviour on the macromechanical behaviour.

  18. Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre composites

    NASA Astrophysics Data System (ADS)

    Hajlane, A.; Miettinen, A.; Madsen, B.; Beauson, J.; Joffe, R.

    2016-07-01

    The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro-mechanical model. The parameters characterizing the microstructure of the composites, e.g. fibre length and orientation distributions, used as input in the model were obtained by micro-tomography. The investigation was carried out on composites with untreated and surface treated fibres with various fibre weight contents (5wt%, 10wt%, and 15wt% for untreated fibres, and 15wt% for treated fibres). The properties of fibres were measured by an automated single fibre tensile test method. Based on these results, the efficiency of the fibre treatment to improve fibre/matrix adhesion is evaluated, and the applicability of the method to measure the interfacial shear strength is discussed. The results are compared with data from previous work, and with other results from the literature.

  19. 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.

  20. 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.

  1. Small punch tensile/fracture test data and 3D specimen surface data on Grade 91 ferritic/martensitic steel from cryogenic to room temperature.

    PubMed

    Bruchhausen, Matthias; Lapetite, Jean-Marc; Ripplinger, Stefan; Austin, Tim

    2016-12-01

    Raw data from small punch tensile/fracture tests at two displacement rates in the temperature range from -196 °C to room temperature on Grade 91 ferritic/martensitic steel are presented. A number of specimens were analyzed after testing by means of X-ray computed tomography (CT). Based on the CT volume data detailed 3D surface maps of the specimens were established. All data are open access and available from Online Data Information Network (ODIN)https://odin.jrc.ec.europa.eu. The data presented in the current work has been analyzed in the research article "On the determination of the ductile to brittle transition temperature from small punch tests on Grade 91 ferritic-martensitic steel" (M. Bruchhausen, S. Holmström, J.-M. Lapetite, S. Ripplinger, 2015) [1].

  2. 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.

  3. PBX 9502 TENSILE ANALYSIS

    SciTech Connect

    Idar, D.J.; Larson, S.A.

    2000-10-01

    With the recent creation of the PX HE Core Surveillance Database, individual specimen surveillance values can be easily compared to the corresponding individual qualification values to evaluate for trends. A review of the data shows a broad scatter in measured stress-strain values. Using the available HE surveillance database, it is clear that the surveillance measurements from the two Cycle 15 charges fall within the range of qualification stress and strain values recorded previously for PBX 9502 lots and that no apparent stockpile-age related trends are evident in the tensile stress-strain data. As a result of this investigation, some changes are being made to the core surveillance specifications to minimize the effects on tensile data scatter due to temperature and humidity differences and method to method changes. These data analyses do point out the need for a comprehensive understanding of the effect of a number of variables, i.e. formulation and pressing method, density, stockpile age, lot-to-lot variations, temperature, and humidity on the mechanical property behavior of HE composite materials. Too often data have been compared without the relevant details made available to determine if the test conditions were nominally the same or different. These results also point out the critical need to establish useful stress-strain limits for qualification and surveillance testing of HEs.

  4. 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.

  5. 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.

  6. Evolution of tensile design stresses for lumber

    Treesearch

    William L. Galligan; C. C. Gerhards; R. L. Ethington

    1979-01-01

    Until approximately 1965, allowable design stresses for lumber in tension were taken as equal to those assigned for bending. As interest in tensile properties increased, testing machines were designed specifically to stress lumber in tension. Research results that accumulated on tensile tests of full-size lumber suggested lower design stresses for tension than for...

  7. Tensile properties of epoxy encapsulants

    SciTech Connect

    Guess, T.R.; Wischmann, K.B.; Stavig, M.E.

    1993-02-01

    Tensile properties were measured for nineteen different formulations of epoxy encapsulating materials. Formulations were of different combinations of two neat resins (Epon 828 and Epon 826, with and without CTBN modification), three fillers (ALOX, GNM and mica) and four hardeners (Z, DEA, DETDA-SA and ANH-2). Five of the formulations were tested at -55, -20, 20 and 60C, one formulation at -55, 20 and 71C; and the remaining formulations at 20C. Complete stress-strain curves are presented along with tables of tensile strength, initial modulus and Poisson's ratio. The stress-strain responses are nonlinear and are temperature dependent. The reported data provide information for comparing the mechanical properties of encapsulants containing the suspected carcinogen Shell Z with the properties of encapsulants containing noncarcinogenic hardeners. Also, calculated shear moduli, based on measured tensile moduli and Poisson's ratio, are in very good agreement with reported shear moduli from experimental torsional pendulum tests.

  8. Tensile properties of epoxy encapsulants

    SciTech Connect

    Guess, T.R.; Wischmann, K.B.; Stavig, M.E.

    1993-02-01

    Tensile properties were measured for nineteen different formulations of epoxy encapsulating materials. Formulations were of different combinations of two neat resins (Epon 828 and Epon 826, with and without CTBN modification), three fillers (ALOX, GNM and mica) and four hardeners (Z, DEA, DETDA-SA and ANH-2). Five of the formulations were tested at -55, -20, 20 and 60C, one formulation at -55, 20 and 71C; and the remaining formulations at 20C. Complete stress-strain curves are presented along with tables of tensile strength, initial modulus and Poisson`s ratio. The stress-strain responses are nonlinear and are temperature dependent. The reported data provide information for comparing the mechanical properties of encapsulants containing the suspected carcinogen Shell Z with the properties of encapsulants containing noncarcinogenic hardeners. Also, calculated shear moduli, based on measured tensile moduli and Poisson`s ratio, are in very good agreement with reported shear moduli from experimental torsional pendulum tests.

  9. 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.

  10. A Novel Approach to Fabricating Fuel Compacts for the Next Generation Nuclear Plant (NGNP)

    SciTech Connect

    Pappano, Peter J; Burchell, Timothy D; Trammell, Michael P; Hunn, John D

    2008-01-01

    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.

  11. Academy of Dental Materials guidance on in vitro testing of dental composite bonding effectiveness to dentin/enamel using micro-tensile bond strength (μTBS) approach.

    PubMed

    Armstrong, Steve; Breschi, Lorenzo; Özcan, Mutlu; Pfefferkorn, Frank; Ferrari, Marco; Van Meerbeek, Bart

    2017-02-01

    An ideal dental adhesive should provide retentive strength, marginal seal, be relatively simple to achieve and demonstrate clinical durability. Future improvements in adhesive bonding to tooth structure require in vitro test methods that provide reliable data for materials development and/or evaluation of experimental variables. The objective of this project was to identify a test method that is relatively easy to perform, repeatable and ultimately useful for predicting clinical outcomes. The Academy of Dental Materials initiated a project to develop and distribute guidance documents on laboratory test methods that are useful for the evaluation of dental adhesives and cements, composite resins and ceramics. The dental adhesive sub-group has identified the micro-tensile bond strength test, especially after subjecting the specimens to a durability challenge, as currently the best practical surrogate measure of dental composite restoration retention. The following μTBS guidance is meant to aid the researcher in conducting the μTBS test. The authors, while recognizing the limitations of a static, strength-based test method, welcome comments and suggestions for improvements of this guidance document in future revisions. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Investigation of adhesive properties of dental composite materials using an improved tensile test procedure and scanning electron microscopy.

    PubMed

    Rider, M; Tanner, A N; Kenny, B

    1977-04-01

    A standardized tension test was used to evaluate the adhesive properties of several composite materials when used on both dentin and enamel specimens. The nature of the test surfaces was examined by roughness tests using a Talysurf machine and also in more detail by means of a scanning electron microscope. Poor results were obtained for the adhesion of composite materials to dentin whereas good retention to enamel was obtained.

  17. 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}.

  18. 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.

  19. 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.

  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. 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.

  2. Improvement in Mechanical Properties of A356 Tensile Test Bars Cast in a Permanent Mold by Application of a Knife Ingate

    NASA Astrophysics Data System (ADS)

    Wang, Yaou; Schwam, David; Neff, David V.; Chen, Chai-Jung; Zhu, Xuejun

    2012-03-01

    As a standard test-bar permanent mold, the "Stahl" Mold has been widely used in foundries to assess the properties of cast alloys. However, inferior mechanical properties are often obtained with this mold due to shrinkage-induced microporosity in the gage section. In order to improve the mechanical properties, a design modification comprising a thin knife ingate between the feeder and test-bar cavity was evaluated in this work. The new design was studied by computer-aided simulation. Simulations predicted that the knife ingate improved the metal feeding capability and reduced the shrinkage microporosity at the gage section from 3 to 1 pct. Experimental verification work has been undertaken with aluminum alloy A356, and the results were analyzed by a statistics theory-based factorial analysis method. The new design resulted in main effects with ultimate tensile strength (UTS) improvement of 20 MPa (relative 12 pct) and elongation increment of 2 pct (relative 45 pct) for the as-cast test bars.

  3. 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.

  4. 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.

  5. 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.

  6. Tensile Properties and Viscoelastic Model of a Polyimide Film

    NASA Astrophysics Data System (ADS)

    Zhang, Shengde; Mori, Syuhei; Sakane, Masao; Nagasawa, Tadashi; Kobayashi, Kaoru

    This paper presents tensile properties of a polyimide thin film used in electronic devices. Tensile tests were performed to determine Young's modulus, proportional limit, yield stress, ultimate tensile strength and elongation of the polyimide film. Effects of strain rate and temperature on the tensile properties were discussed. There was a little effect of strain rate on Young's modulus but proportional limit, yield stress and ultimate tensile strength increased with increasing strain rate. Only elongation decreased with strain rate. Young's modulus, proportional limit, yield stress and ultimate tensile strength decreased with increasing temperature, but elongation increased. Applicability of a viscoelastic model for describing the stress-strain curves of the polyimide film was discussed.

  7. Space-resolved diffusing wave spectroscopy measurements of the macroscopic deformation and the microscopic dynamics in tensile strain tests

    NASA Astrophysics Data System (ADS)

    Nagazi, Med-Yassine; Brambilla, Giovanni; Meunier, Gérard; Marguerès, Philippe; Périé, Jean-Noël; Cipelletti, Luca

    2017-01-01

    We couple a laser-based, space-resolved dynamic light scattering apparatus to a universal traction machine for mechanical extensional tests. We perform simultaneous optical and mechanical measurements on polyether ether ketone, a semi-crystalline polymer widely used in the industry. Due to the high turbidity of the sample, light is multiply scattered by the sample and the diffusing wave spectroscopy (DWS) formalism is used to interpret the data. Space-resolved DWS yields spatial maps of the sample strain and of the microscopic dynamics. An excellent agreement is found between the strain maps thus obtained and those measured by a conventional stereo-digital image correlation technique. The microscopic dynamics reveals both affine motion and plastic rearrangements. Thanks to the extreme sensitivity of DWS to displacements as small as 1 nm, plastic activity and its spatial localization can be detected at an early stage of the sample strain, making the technique presented here a valuable complement to existing material characterization methods.

  8. 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.

  9. 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.; Martinez, D.; Trujillo, C. P.; Brown, A. D.; Cerreta, E. K.; Hazell, P. J.; Ferry, M.; Quadir, M. Z.; Jiang, J.; Escobedo, J. P.

    2017-01-01

    The effects of impact velocity and temperature on the dynamic mechanical behavior of two bulk metallic (BMG) alloys 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 both room temperature and 250°C. The samples impacted steel extrusion dies which subjected the bullets to high strains at relatively high strain-rates. The extruded fragments were subsequently soft recovered by using low density foams and examined by means of optical/scanning electron microscopy and differential scanning calorimetry. It was found that shear banding was the dictating mechanism responsible for the fracture of all BMGs. At room temperature, the Zr55Cu30Ni5Al30 alloy exhibited a higher resistance to fragmentation than the Zr46Cu38Ag8Al38 alloy. At 250°C, significant melting was observed in the recovered fragments of both alloys, which indicates that the BMG glassy structure undergoes a melting process and deformation likely occurs homogeneously.

  10. 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.

  11. 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.

  12. Micromechanics of ultra-toughened electrospun PMMA/PEO fibres as revealed by in-situ tensile testing in an electron microscope

    NASA Astrophysics Data System (ADS)

    Andersson, Richard L.; Ström, Valter; Gedde, Ulf W.; Mallon, Peter E.; Hedenqvist, Mikael S.; Olsson, Richard T.

    2014-09-01

    A missing cornerstone in the development of tough micro/nano fibre systems is an understanding of the fibre failure mechanisms, which stems from the limitation in observing the fracture of objects with dimensions one hundredth of the width of a hair strand. Tensile testing in the electron microscope is herein adopted to reveal the fracture behaviour of a novel type of toughened electrospun poly(methyl methacrylate)/poly(ethylene oxide) fibre mats for biomedical applications. These fibres showed a toughness more than two orders of magnitude greater than that of pristine PMMA fibres. The in-situ microscopy revealed that the toughness were not only dependent on the initial molecular alignment after spinning, but also on the polymer formulation that could promote further molecular orientation during the formation of micro/nano-necking. The true fibre strength was greater than 150 MPa, which was considerably higher than that of the unmodified PMMA (17 MPa). This necking phenomenon was prohibited by high aspect ratio cellulose nanocrystal fillers in the ultra-tough fibres, leading to a decrease in toughness by more than one order of magnitude. The reported necking mechanism may have broad implications also within more traditional melt-spinning research.

  13. Micromechanics of ultra-toughened electrospun PMMA/PEO fibres as revealed by in-situ tensile testing in an electron microscope

    PubMed Central

    Andersson, Richard L.; Ström, Valter; Gedde, Ulf W.; Mallon, Peter E.; Hedenqvist, Mikael S.; Olsson, Richard T.

    2014-01-01

    A missing cornerstone in the development of tough micro/nano fibre systems is an understanding of the fibre failure mechanisms, which stems from the limitation in observing the fracture of objects with dimensions one hundredth of the width of a hair strand. Tensile testing in the electron microscope is herein adopted to reveal the fracture behaviour of a novel type of toughened electrospun poly(methyl methacrylate)/poly(ethylene oxide) fibre mats for biomedical applications. These fibres showed a toughness more than two orders of magnitude greater than that of pristine PMMA fibres. The in-situ microscopy revealed that the toughness were not only dependent on the initial molecular alignment after spinning, but also on the polymer formulation that could promote further molecular orientation during the formation of micro/nano-necking. The true fibre strength was greater than 150 MPa, which was considerably higher than that of the unmodified PMMA (17 MPa). This necking phenomenon was prohibited by high aspect ratio cellulose nanocrystal fillers in the ultra–tough fibres, leading to a decrease in toughness by more than one order of magnitude. The reported necking mechanism may have broad implications also within more traditional melt–spinning research. PMID:25208692

  14. 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

  15. 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.

  16. 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.

  17. Low-temperature Mechanical Properties of Fe-0.06C-18Cr-10Ni-0.4Ti Austenitic Steel Determined Using Ring-Pull Tensile Tests and Microhardness Measurements

    SciTech Connect

    Neustroev, V. S.; Boev, E. V.; Garner, Francis A.

    2007-08-01

    Irradiated austenitic stainless steels removed from Russian water-cooled VVERs experience irradiation temperatures and He/dpa conditions that are very similar to steels to be used in ITER. Data are presented on the radiation hardening of the Russian analog of AISI 321 at 0.2 to 15 dpa in the range of 285 to 320оС. The Russian variant of the ring-pull tensile test was used to obtain mechanical prop-erty data. Microhardness tests on the ring specimens provide useful information throughout the deformed regions, but at high hardening levels caution must be exercised before application of a widely accepted hardness-yield stress correla-tion to prediction of tensile properties. Low-nickel austenitic steels are very prone to form deformation martensite, a phase that increases strongly with the larger deformation levels characteristic of microhardness tests, especially when compared to the 0.2% deformation used to define yield stress.

  18. 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.

  19. Unified tensile fracture criterion.

    PubMed

    Zhang, Z F; Eckert, J

    2005-03-11

    We find that the classical failure criteria, i.e., maximum normal stress criterion, Tresca criterion, Mohr-Coulomb criterion, and von Mises criterion, cannot satisfactorily explain the tensile fracture behavior of the bulk metallic glass (BMG) materials. For a better description, we propose an ellipse criterion as a new failure criterion to unify the four classical criteria above and apply it to exemplarily describe the tensile fracture behavior of BMGs as well as a variety of other materials. It is suggested that each of the classical failure criteria can be unified by the present ellipse criterion depending on the difference of the ratio alpha=tau(0)/sigma(0).

  20. 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.

  1. Evaluating Freeze-Thaw Deterioration with Tensile Strength

    NASA Astrophysics Data System (ADS)

    Komar, A. J. K.; Boyd, A. J.

    2017-06-01

    Freeze-thaw damage is one of the leading contributors to infrastructure deterioration in temperate northern climates. Deterioration caused by freeze-thaw cycling is primarily induced by hydraulic pressures within the hydrated cement paste matrix that cause tensile cracking. Such damage should, therefore, be more effectively detected with tensile testing. This work presents the detection and evaluation of ongoing freeze-thaw (F/T) damage in plain concrete cylinders using the pressure tensile strength test, as it compares to compressive strength evaluation. Pressure tension test results exhibited significantly higher levels of deterioration compared to compression testing, with the samples losing up to 90% of their undamaged tensile capacity. Moreover, it was shown that tensile strength testing is far more sensitive to freeze-thaw deterioration, evidenced by a significant drop in the tensile to compressive strength ratio to below 5%.

  2. 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

  3. 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.

  4. Assessment of Candidate Molten Salt Coolants for the NGNP/NHI Heat-Transfer Loop

    SciTech Connect

    Williams, D. F.

    2006-06-30

    This report provides an assessment of candidate salts proposed as the coolant for the loop that shuttles heat from the Next Generation Nuclear Plant (NGNP) to the Nuclear Hydrogen Initiative (NHI) hydrogen-production plant. The physical properties most relevant for coolant service were reviewed, and key chemical factors that influence material compatibility were also analyzed for the purpose of screening candidate salts. A preliminary assessment of the cost of the raw materials required to produce the coolant is also presented. Salts that are suitable for use as the primary coolant in a high-temperature nuclear reactor were previously analyzed. Some of the fluoride salts identified in the previous study are also appropriate for consideration as the secondary coolant in a heat-transfer loop; therefore, results from the previous report are used in this document. However, alternative coolant salts (i.e., chlorides and fluoroborates) that were not considered in the previous report should be considered for service in the heat-transfer loop. These alternative coolants are considered in this report.

  5. Tensile test of a silicon microstructure fully coated with submicrometer-thick diamond like carbon film using plasma enhanced chemical vapor deposition method

    NASA Astrophysics Data System (ADS)

    Zhang, Wenlei; Uesugi, Akio; Hirai, Yoshikazu; Tsuchiya, Toshiyuki; Tabata, Osamu

    2017-06-01

    This paper reports the tensile properties of single-crystal silicon (SCS) microstructures fully coated with sub-micrometer thick diamond like carbon (DLC) film using plasma enhanced chemical vapor deposition (PECVD). To minimize the deformations or damages caused by non-uniform coating of DLC, which has high compression residual stress, released SCS specimens with the dimensions of 120 µm long, 4 µm wide, and 5 µm thick were coated from the top and bottom side simultaneously. The thickness of DLC coating is around 150 nm and three different bias voltages were used for deposition. The tensile strength improved from 13.4 to 53.5% with the increasing of negative bias voltage. In addition, the deviation in strength also reduced significantly compared to bare SCS sample.

  6. Tensile properties of irradiated surveillance coupons

    SciTech Connect

    Huang, F.H.; Blackburn, L.D.

    1994-06-01

    Tensile testing of austenitic steel and superalloy samples irradiated in the HMO 13 assembly was performed in support of the Fast Flux Test Facility (FFTF) Surveillance Program. Postirradiation yield stress, ultimate tensile stress, uniform elongation, total elongation, and reduction in area of 304 stainless steel (SS), 308 SS weld, 316 SS, A286, In718, and In718 weld were determined. Results showed the strength of austenitic steels increased while the ductility decreased as a result of irradiation. Low irradiation exposure produced little property change in In718. Overall, the tensile properties of HMO 13 surveillance coupons showed a lower magnitude of irradiation-induced property change than was expected based on earlier studies. Results from these tests gave no indications of unexpectedly severe irradiation damage to FFTF components.

  7. 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.

  8. 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.

  9. Tritium Movement and Accumulation in the NGNP System Interface and Hydrogen Plant

    SciTech Connect

    Hirofumi Ohashi; Steven R. Sherman

    2007-06-01

    Tritium movement and accumulation in a Next Generation Nuclear Plant with a hydrogen plant using a high temperature electrolysis process and a thermochemical water splitting sulfur iodine process are estimated by the numerical code THYTAN as a function of design, operational, and material parameters. Estimated tritium concentrations in the hydrogen product and in process chemicals in the hydrogen plant of the Next Generation Nuclear Plant using the high temperature electrolysis process are slightly higher than the drinking water limit defined by the U.S. Environmental Protection Agency and the limit in the effluent at the boundary of an unrestricted area of a nuclear plant as defined by the U.S. Nuclear Regulatory Commission. However, these concentrations can be reduced to within the limits through use of some designs and modified operations. Tritium concentrations in the Next Generation Nuclear Plant using the Sulfur-Iodine Process are significantly higher as calculated and are affected by parameters with large uncertainties (i.e., tritium permeability of the process heat exchanger, the hydrogen concentration in the heat transfer and process fluids, the equilibrium constant of the isotope exchange reaction between HT and H2SO4). These parameters, including tritium generation and the release rate in the reactor core, should be more accurately estimated in the near future to improve the calculations for the NGNP using the Sulfur-Iodine Process. Decreasing the tritium permeation through the heat exchanger between the primary and secondary circuits may be an an effective measure for decreasing tritium concentrations in the hydrogen product, the hydrogen plant, and the tertiary coolant.

  10. 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.

  11. 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.

  12. 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.

  13. Dataset of tensile strength development of concrete with manufactured sand.

    PubMed

    Zhao, Shunbo; Hu, Feijia; Ding, Xinxin; Zhao, Mingshuang; Li, Changyong; Pei, Songwei

    2017-04-01

    This article presents 755 groups splitting tensile strength tests data of concrete with manufactured sand (MSC) in different curing age ranged from 1 day to 388 days related to the research article "Experimental study on tensile strength development of concrete with manufactured sand" (Zhao et al., 2017) [1]. These data were used to evaluate the precision of the prediction formulas of tensile strength of MSC, and can be applied as dataset for further studies.

  14. 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.

  15. Mechanical properties of LaFe11.5Si1.5/Cu negative thermal composite and its application as clamp materials for tensile test at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Shan, Y.; Huang, R.; Zhao, Y.; Huang, C.; Li, L.

    2017-09-01

    La (Fe, Si)13 compounds have been widely studied for their excellent negative thermal expansion (NTE) properties. However, their poor mechanical properties limit their practical applications. In this work, LaFe11.5Si1.5/Cu material was fabricated. It was found that the NTE behavior occurs obviously at cryogenic temperatures and the ratio of ΔL/L can reach to 0.12%. Mechanical tests indicated that the absolute value of compressive strength at 77K and 300K is 365MPa and 222MPa, respectively. The elastic modulus at 77K and 300K is -109GPa and -87GPa, respectively. In addition, the average hardness is 337Hv performed in the Vickers hardness tester. Loose between the samples and clamps in the tensile test due to the contraction of clamp at low temperatures remains a big issue. In order to solve this problem, some LaFe11.5Si1.5/Cu NTE sheets are added between the clamp and the tested samples. Results showed that the samples with NTE materials sheets embedded is held tighter by the clamp. The maximum force of the tensile test is 9.77N and 5.48N, respectively, which illustrates that the adding of NTE material does make sense.

  16. High-Tensile Strength Tape Versus High-Tensile Strength Suture: A Biomechanical Study.

    PubMed

    Gnandt, Ryan J; Smith, Jennifer L; Nguyen-Ta, Kim; McDonald, Lucas; LeClere, Lance E

    2016-02-01

    To determine which suture design, high-tensile strength tape or high-tensile strength suture, performed better at securing human tissue across 4 selected suture techniques commonly used in tendinous repair, by comparing the total load at failure measured during a fixed-rate longitudinal single load to failure using a biomechanical testing machine. Matched sets of tendon specimens with bony attachments were dissected from 15 human cadaveric lower extremities in a manner allowing for direct comparison testing. With the use of selected techniques (simple Mason-Allen in the patellar tendon specimens, whip stitch in the quadriceps tendon specimens, and Krackow stitch in the Achilles tendon specimens), 1 sample of each set was sutured with a 2-mm braided, nonabsorbable, high-tensile strength tape and the other with a No. 2 braided, nonabsorbable, high-tensile strength suture. A total of 120 specimens were tested. Each model was loaded to failure at a fixed longitudinal traction rate of 100 mm/min. The maximum load and failure method were recorded. In the whip stitch and the Krackow-stitch models, the high-tensile strength tape had a significantly greater mean load at failure with a difference of 181 N (P = .001) and 94 N (P = .015) respectively. No significant difference was found in the Mason-Allen and simple stitch models. Pull-through remained the most common method of failure at an overall rate of 56.7% (suture = 55%; tape = 58.3%). In biomechanical testing during a single load to failure, high-tensile strength tape performs more favorably than high-tensile strength suture, with a greater mean load to failure, in both the whip- and Krackow-stitch models. Although suture pull-through remains the most common method of failure, high-tensile strength tape requires a significantly greater load to pull-through in a whip-stitch and Krakow-stitch model. The biomechanical data obtained in the current study indicates that high-tensile strength tape may provide better repair

  17. 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.

  18. Low-Temperature Mechanical Properties Of Fe-0.06c-18cr-10ni-0.4ti Austenitic Steel Determined Using Ring-Pull Tensile Tests And Microhardness Measurements

    SciTech Connect

    Neustroev, V. S.; Boev, E. V.; Garner, Francis A.

    2007-03-01

    Irradiated austenitic stainless steels removed from Russian water-cooled VVERs experience irradia-tion temperatures and He/dpa conditions that are very similar to steels to be used in ITER. Data are presented on the radiation hardening of the Russian analog of AISI 321 at 0.2 to 15 dpa in the range of 285 to 320оС. The Russian variant of the ring-pull tensile test was used to obtain mechanical prop-erty data. Microhardness tests on the ring specimens provide useful information throughout the de-formed regions, but at high hardening levels caution must be exercised before application of a widely accepted hardness-yield stress correlation to prediction of tensile properties. Low-nickel austenitic steels are very prone to form deformation martensite, a phase that increases strongly with the larger deformation levels characteristic of microhardness tests, especially when compared to the 0.2% de-formation used to define yield stress.

  19. Mechanical shear and tensile characteristics of selected biomass stems

    USDA-ARS?s Scientific Manuscript database

    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...

  20. Theoretical investigations into the influence of the position of a breaking line on the tensile failure of flat, round, bevel-edged tablets using finite element methodology (FEM) and its practical relevance for industrial tablet strength testing.

    PubMed

    Podczeck, Fridrun; Newton, J Michael; Fromme, Paul

    2014-12-30

    Flat, round tablets may have a breaking ("score") line. Pharmacopoeial tablet breaking load tests are diametral in their design, and industrially used breaking load testers often have automatic tablet feeding systems, which position the tablets between the loading platens of the machine with the breaking lines in random orientation to the applied load. The aim of this work was to ascertain the influence of the position of the breaking line in a diametral compression test using finite element methodology (FEM) and to compare the theoretical results with practical findings using commercially produced bevel-edged, scored tablets. Breaking line test positions at an angle of 0°, 22.5°, 45°, 67.5° and 90° relative to the loading plane were studied. FEM results obtained for fully elastic and elasto-plastic tablets were fairly similar, but they highlighted large differences in stress distributions depending on the position of the breaking line. The stress values at failure were predicted to be similar for tablets tested at an angle of 45° or above, whereas at lower test angles the predicted breaking loads were up to three times larger. The stress distributions suggested that not all breaking line angles would result in clean tensile failure. Practical results, however, did not confirm the differences in the predicted breaking loads, but they confirmed differences in the way tablets broke. The results suggest that it is not advisable to convert breaking loads obtained on scored tablets into tablet tensile strength values, and comparisons between different tablets or batches should carefully consider the orientation of the breaking line with respect to the loading plane, as the failure mechanisms appear to vary. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Investigation of the Microstructure Evolution in a Fe-17Mn-1.5Al-0.3C Steel via In Situ Synchrotron X-ray Diffraction during a Tensile Test.

    PubMed

    Ma, Yan; Song, Wenwen; Bleck, Wolfgang

    2017-09-25

    The quantitative characterization of the microstructure evolution in high-Mn steel during deformation is of great importance to understanding its strain-hardening behavior. In the current study, in situ high-energy synchrotron X-ray diffraction was employed to characterize the microstructure evolution in a Fe-17Mn-1.5Al-0.3C steel during a tensile test. The microstructure at different engineering strain levels-in terms of ε-martensite and α'-martensite volume fractions, the stacking fault probability, and the twin fault probability-was analyzed by the Rietveld refinement method. The Fe-17Mn-1.5Al-0.3C steel exhibits a high ultimate tensile strength with a superior uniform elongation and a high strain-hardening rate. The remaining high strain-hardening rate at the strain level about 0.025 to 0.35 results from ε-martensite dominant transformation-induced-plasticity (TRIP) effect. The increase in the strain-hardening rate at the strain level around 0.35 to 0.43 is attributed to the synergetic α'-martensite dominant TRIP and twinning-induced-plasticity (TWIP) effects. An evaluation of the stacking fault energy (SFE) of the Fe-17Mn-1.5Al-0.3C steel by the synchrotron measurements shows good agreement with the thermodynamic calculation of the SFE.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Ultrasound transmission measurements for tensile strength evaluation of tablets.

    PubMed

    Simonaho, Simo-Pekka; Takala, T Aleksi; Kuosmanen, Marko; Ketolainen, Jarkko

    2011-05-16

    Ultrasound transmission measurements were performed to evaluate the tensile strength of tablets. Tablets consisting of one ingredient were compressed from dibasic calcium phosphate dehydrate, two grades of microcrystalline cellulose and two grades of lactose monohydrate powders. From each powder, tablets with five different tensile strengths were directly compressed. Ultrasound transmission measurements were conducted on every tablet at frequencies of 2.25 MHz, 5 MHz and 10 MHz and the speed of sound was calculated from the acquired waveforms. The tensile strength of the tablets was determined using a diametrical mechanical testing machine and compared to the calculated speed of sound values. It was found that the speed of sound increased with the tensile strength for the tested excipients. There was a good correlation between the speed of sound and tensile strength. Moreover, based on the statistical tests, the groups with different tensile strengths can be differentiated from each other by measuring the speed of sound. Thus, the ultrasound transmission measurement technique is a potentially useful method for non-destructive and fast evaluation of the tensile strength of tablets. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Effect of tensile stress on cavitation damage formation in mercury

    NASA Astrophysics Data System (ADS)

    Naoe, Takashi; Kogawa, Hiroyuki; Yamaguchi, Yoshihito; Futakawa, Masatoshi

    2010-03-01

    Cavitation erosion or so called pitting damage was investigated under tensile stress conditions in mercury. In MW-class liquid metal spallation targets, pitting damage is a critical issue to satisfy required power and/or lifetime of the target vessel. Cavitation occurs by negative pressure which is induced through pressure wave propagation due to proton beam injection. Pitting damage is formed by microjet and/or shock wave during cavitation bubble collapse. A mercury target vessel suffers tensile stress due to thermal stress or welding. In order to investigate the effect of tensile stress on pitting damage formation, cavitation erosion tests were performed using stress imposed specimens in mercury. An ultrasonic vibratory horn and electro-Magnetic IMpact Testing Machine (MIMTM) were used to vary the cavitation intensity. In the incubation period of pitting damage, damaged area was slightly increased with increasing imposed tensile stress. In the steady state period, a mean depth of erosion was increased by the tensile stress. Additionally, in order to quantitatively evaluate the effect of tensile stress, an indentation test with Vickers indenter was carried out to quasi-statically simulate the impact load. From the measurement of the diagonal length of the indent aspect ratio and hardness, it is recognized that the threshold of the deformation, i.e. pitting damage formation, was decreased by the tensile stress.

  8. 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.

  9. 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.

  10. The tensile properties of single sugar palm (Arenga pinnata) fibre

    NASA Astrophysics Data System (ADS)

    Bachtiar, D.; Sapuan, S. M.; Zainudin, E. S.; Khalina, A.; Dahlan, K. Z. M.

    2010-05-01

    This paper presents a brief description and characterization of the sugar palm fibres, still rare in the scientific community, compared to other natural fibres employed in polymeric composites. Sugar palm fibres are cellulose-based fibres extracted from the Arenga pinnata plant. The characterization consists of tensile test and the morphological examination. The average tensile properties results of fibres such as Young's modulus is equal to 3.69 GPa, tensile strength is equal to 190.29 MPa, and strain at failure is equal to 19.6%.

  11. Tensile Strength of Polyester Composites Reinforced with Thinner Ramie Fibers

    NASA Astrophysics Data System (ADS)

    Monteiro, Sergio Neves; de Pontes, Lucas Almeida; Margem, Frederico Muylaert; Ferreira, Jordana; Netto, Pedro Amoy; Margem, Jean Igor

    This study evaluated the tensile properties of polyester composites reinforced with ramie fibers with thinner diameters. Specimens with different ramie fibers percentages (0,10,20 and 30%) in continuous and aligned ramie stalk fibers volume, were tensile tested at room temperature to evaluate the ultimate strength, elastic modulus and total strain. The results indicated that the tensile properties tend to improve with increasing volume fraction of ramie fibers. The role played by the fiber/matrix interaction was analyzed by scanning electron microscopy.

  12. 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.

  13. 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.

  14. Evaluation of tensile strength of tissue adhesives and sutures for clear corneal incisions using porcine and bovine eyes, with a novel standardized testing platform.

    PubMed

    Kaja, Simon; Goad, Daryl L; Ali, Fatima; Abraham, Ashley; Rebenitsch, R Luke; Teymoorian, Savak; Krishna, Rohit; Koulen, Peter

    2012-01-01

    Tissue adhesives for ophthalmologic applications were proposed almost 50 years ago, yet to date no adequate tissue glues have been identified that combine strong sealing properties with adequate safety and absence of postsurgical side effects. In recent years, cataract surgeries and Descemet's stripping with endothelial keratoplasty procedures have significantly increased the number of clear corneal incisions performed. One of the obstacles to discovery and development of novel tissue adhesives has been the result of nonstandardized testing of potential tissue glues. We developed an instrument capable of controlling intraocular pressure in explanted porcine and bovine eyes in order to evaluate sealants, adhesives, and surgical closure methods used in ophthalmic surgery in a controlled, repeatable, and validated fashion. We herein developed and validated our instrument by testing the adhesive properties of cyanoacrylate glue in both porcine and bovine explant eyes. The instrument applied and maintained intraocular pressure through a broad range of physiological intraocular pressures. Cyanoacrylate-based glues showed significantly enhanced sealing properties of clear corneal incisions compared with sutured wounds. This study shows the feasibility of our instrument for reliable and standardized testing of tissue adhesive for ophthalmological surgery.

  15. 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.

  16. 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.

  17. Multiphasic stress relaxation response of freshly isolated and cultured vascular smooth muscle cells measured by quasi-in situ tensile test.

    PubMed

    Nagayama, Kazuaki; Saito, Shunsuke; Matsumoto, Takeo

    2015-01-01

    Vascular smooth muscle cells (SMCs) undergo a phenotypic change from a contractile to a synthetic state under pathological conditions, such as atherogenesis and restenosis. Although the viscoelastic properties of SMCs are of particular interest because of their role in the development of these vascular diseases, the effects of phenotypic changes on their viscoelastic properties are unclear at this stage. We performed the stress relaxation test at constant strain (ε=30%) for the freshly isolated contractile SMCs (FSMCs) and the cultured synthetic SMCs (CSMCs) maintaining in situ cell shape and cytoskeletal integrity. We also investigated the effect of extracellular Ca2+ on their viscoelastic behaviors. FSMCs and CSMCs exhibited multiphasic stress relaxation, which consisted of rapid relaxation, occurring on a time scale of several seconds and several 10 seconds, and slow relaxation occurring on a time scale of 1000 seconds. The estimated elastic modulus of CSMCs was less than one-half that of FSMCs, that was associated with a decreased of amount of actin stress fibers (SFs) during the transition from contractile to synthetic phenotypes. FSMCs showed a conservation of tension with extracellular Ca2+ following rapid stress relaxation. In contrast, CSMCs showed a consecutive decrease in tension independent of Ca2+. This suggests that the decrease in tension in a long time scale may be involved in mechanical remodeling of SFs induced through a Rho-dependent pathway, which is Ca2+-independent and become predominant in the transition from contractile to synthetic phenotypes.

  18. 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.

  19. 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.

  20. Tensile and creep behavior of a silicon carbide fiber-reinforced aluminosilicate composite

    SciTech Connect

    Khobaib, M.; Zawada, L.

    1991-08-01

    Tensile and tensile creep tests were conducted with a Nicalon/aluminosilicate (Si-C-O/1723) glass composite. Tensile tests were conducted at room temperature, and the creep tests were conducted at 600, 700, and 750 C. Room temperature tensile test failure features exhibited a tortuous crack path and extensive fiber pull-out. The failure features in creep were characterized by flat fracture and little fiber pull-out. The environment appeared to play a significant role in creep failure of this composite system. 6 refs.

  1. Analysis of tensile bond strengths using Weibull statistics.

    PubMed

    Burrow, Michael F; Thomas, David; Swain, Mike V; Tyas, Martin J

    2004-09-01

    Tensile strength tests of restorative resins bonded to dentin, and the resultant strengths of interfaces between the two, exhibit wide variability. Many variables can affect test results, including specimen preparation and storage, test rig design and experimental technique. However, the more fundamental source of variability, that associated with the brittle nature of the materials, has received little attention. This paper analyzes results from micro-tensile tests on unfilled resins and adhesive bonds between restorative resin composite and dentin in terms of reliability using the Weibull probability of failure method. Results for the tensile strengths of Scotchbond Multipurpose Adhesive (3M) and Clearfil LB Bond (Kuraray) bonding resins showed Weibull moduli (m) of 6.17 (95% confidence interval, 5.25-7.19) and 5.01 (95% confidence interval, 4.23-5.8). Analysis of results for micro-tensile tests on bond strengths to dentin gave moduli between 1.81 (Clearfil Liner Bond 2V) and 4.99 (Gluma One Bond, Kulzer). Material systems with m in this range do not have a well-defined strength. The Weibull approach also enables the size dependence of the strength to be estimated. An example where the bonding area was changed from 3.1 to 1.1 mm diameter is shown. Weibull analysis provides a method for determining the reliability of strength measurements in the analysis of data from bond strength and tensile tests on dental restorative materials.

  2. Tensile Mechanics of Bamboo Strips

    NASA Astrophysics Data System (ADS)

    Bahari, S. A.; Ahmad, M.; Nordin, K.; Jamaludin, M. A.

    2010-03-01

    Mechanical properties of Semantan bamboo (Gigantochloa scortechinii) strips loaded in tensile parallel to grain were documented. The specimens were taken from bottom, middle and top portions of bamboo culms. In each portion, specimens were taken from internodes and node parts. Specimens from internodes part indicated absence of node while specimens from nodes indicated presence of node at the middle section of each specimen. From the results, there was an increment of tensile mechanic values for Semantan bamboo strips in bottom to top portions, due to the increment of fibro vascular bundles amount in the respective portions. Generally, the failures modes of bamboo strips loaded in tensile were divided into Splintering (Mode I) and Brittle Splintering (Mode II). Mode I occurred in internodes of all portions while Mode II occurred in node. Mode I presented higher tensile mechanic values due to the fibres behaviour of bamboo strips, which is more compact, longer and parallel with axial and uniform grain orientation, compared to the short, forked and crossed fibres as well as uneven orientation of vascular bundles in Mode II.

  3. On the tensile strength of soil grains in Hertzian response

    NASA Astrophysics Data System (ADS)

    Nadimi, Sadegh; Fonseca, Joana

    2017-06-01

    The breakage initiation of soil grains is controlled by its tensile capacity. Despite the importance of tensile strength, it is often disregarded due to difficulties in measurement. This paper presents an experimental and numerical investigation on the effect of tensile strength on Hertzian response of a single soil grain. Hertz theory is commonly used in numerical simulation to present the contact constitutive behaviour of a purely elastic grain under normal loading. This normal force:displacement comes from stress distribution and concentration inside the grain. When the stress reaches the tensile capacity, a crack initiates. A series of numerical tests have been conducted to determine the sensitivity of Hertzian response to the selected tensile strength used as an input data. An elastic-damage constitutive model has been employed for spherical grains in a combined finite-discrete element framework. The interpretation of results was enriched by considering previous theoretical work. In addition, systematic experimental tests have been carried out on both spherical glass beads and grains of two different sands, i.e. Leighton Buzzard silica sand and coarse carbonate sand from Persian Gulf. The preliminary results suggest that lower tensile strength leads to a softer response under normal loading. The wider range of responses obtained for the carbonate sand, are believed to be related to the large variety of grain shape associated with bioclastic origin of the constituent grains.

  4. Study of the {alpha}{double_prime} phase texture obtained by martensitic {beta}-{alpha}{double_prime} phase transformation induced by tensile test in a sheet of Ti5Al2Sn4Zr4Mo2Cr1Fe

    SciTech Connect

    Pionnier, D.; Humbert, M.; Philippe, M.J.; Combres, Y.

    1998-10-09

    The purpose was to investigate the texture development of the {alpha}{double_prime} orthorhombic martensite phase induced by stress within a commercial sheet of Ti5Al2Sn4Zr4Mo2Cr1Fe. First, the experimental textures of the initial b.c.c. phase, then of the b.c.c. phase and the {alpha}{double_prime} martensite phase after a uniaxial deformation were determined from pole figures. Comparison of the {alpha}{double_prime} experimental texture with a {alpha}{double_prime} texture, simulated with no variant selection from the b.c.c. texture of the initial {beta} matrix clearly shows that a strong variant selection was induced by stress. In order to better understand the formation of this {alpha}{double_prime} orthorhombic texture, texture transformations were simulated according to different variant selection assumptions. As a result, it was shown that the {alpha}{double_prime} orthorhombic texture is formed by the variants favorably oriented with respect to stresses induced during tensile test.

  5. Effect of specimen geometry on tensile strength of cortical bone.

    PubMed

    Feng, Liang; Jasiuk, Iwona

    2010-11-01

    We investigate the effect of specimen geometry on the ultimate tensile strength of cortical bone measured by a tensile test. This article is motivated by the fact that there is no clear consensus in the literature on a suitable specimen shape for cortical bone testing. We consider three commonly used tensile test specimen shapes: strip, dumbbell with sharp junctions, and dumbbell with rounded junctions. We conduct this study computationally, using a finite element method, and experimentally by testing porcine femurs. Our results show that local stress concentration factors in the specimen lead to reduced values in the measured tensile strength. The higher the stress concentrations are, the lower is the measured strength. We find that the strip specimens are not a good choice due to high stress concentrations. For the same reason, dumbbell specimens with sharp junctions between the grip and gage sections should also be avoided. The dumbbell shaped tensile test specimens with an arc transition and a maximized radius of fillet are a better choice because such geometry lowers stress concentrations.

  6. 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.

  7. 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.

  8. 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.

  9. Tensile properties of ceramic matrix fiber composites

    SciTech Connect

    Shin, D.W.; Auh, K.H.; Tanaka, Hidehiko

    1995-11-01

    The mechanical properties of various 2D ceramic matrix fiber composites were characterized by tension testing, using the gripping and alignment techniques developed in this work. The woven fabric composites used for the test had the basic combinations of Al{sub 2}O{sub 3} fabric/Al{sub 2}O{sub 3}, SiC fabric/SiC, and SiC monofilament uniweave fabric/SiC. Tension testing was performed with strain gauge and acoustic emission instrumentation to identify the first-matrix cracking stress and assure a valid alignment. The peak tensile stresses of these laminate composites were about one-third of the flexural strengths. The SiC monofilament uniweave fabric (14 vol%)/SiC composites showed a relatively high peak stress of 370 MPa in tension testing.

  10. Effect of Electron Beam Irradiation on Tensile Strength of Polypropylene

    NASA Astrophysics Data System (ADS)

    Yamada, Hiroshi; Ikeda, Masayuki; Shimbo, Minoru; Miyano, Yasushi

    In this paper, the effects of the intensity of electron beam and the variation with time after irradiation of electron beam on the tensile strength of the polypropylene (PP), which is widely used as medicine containers, were investigated. PP with and without colorants were used first and samples irradiated under various intensity of EB. A tensile test on the irradiated samples with elapsed time after the irradiation of the electron beam was carried out. The effects of those factors on the tensile strength were discussed. The following results were obtained (1) The tensile strength of PP decreased due to the influence of the electron beam irradiation, however the rate of the decrease in strength was small compared with the original one. Furthermore, the rate of the decrease in strength was very small owing to the variation with time after the EB irradiation. (2) The tensile rupture strength of PP increased and the rupture strain owing to the influence of the electron beam irradiation compared with the original one. In addition, these rupture strength increased and the rupture strain decreased along with time after the irradiation of the electron beam. (3) The tensile rupture strain energy of PP decreased owing to the influence of the electron beam irradiation compared with the original one. In addition, the strain energy decreases with time after the irradiation of the electron beam. Moreover, the strength characteristics of PP with colorants received greater influence of electron beam compared with the one without colorants.

  11. 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.

  12. 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. ...

  13. 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. [24 FR 8771, Oct. 29, 1959. Redesignated...

  14. 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. ...

  15. 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....

  16. Tensile strength on friction stir processed AMg5 (5083) aluminum alloy

    NASA Astrophysics Data System (ADS)

    Chumaevsky, A. V.; Eliseev, A. A.; Filippov, A. V.; Rubtsov, V. E.; Tarasov, S. Yu.

    2016-11-01

    The results of the tensile tests carried out both on AMg5 (5083) aluminum alloy samples base and those obtained using friction stir processing technique are reported. The tensile test samples have been prepared from the friction stir processed plates so that their tensile axis was parallel to the processing direction. The maximum tensile strength of the processed samples was 9% higher than of the base metal. The fractographic examination shows the presence of flat areas inherent of the brittle fracture in all three friction processed samples. The load-extension curves show that friction stir processing may suppress the serrated yielding.

  17. Tensile Mechanical Property of Oil Palm Empty Fruit Bunch Fiber Reinforced Epoxy Composites

    NASA Astrophysics Data System (ADS)

    Ghazilan, A. L. Ahmad; Mokhtar, H.; Shaik Dawood, M. S. I.; Aminanda, Y.; Ali, J. S. Mohamed

    2017-03-01

    Natural, short, untreated and randomly oriented oil palm empty fruit bunch fiber reinforced epoxy composites were manufactured using vacuum bagging technique with 20% fiber volume composition. The performance of the composite was evaluated as an alternative to synthetic or conventional reinforced composites. Tensile properties such as tensile strength, modulus of elasticity and Poisson’s ratio were compared to the tensile properties of pure epoxy obtained via tensile tests as per ASTM D 638 specifications using Universal Testing Machine INSTRON 5582. The tensile properties of oil palm empty fruit bunch fiber reinforced epoxy composites were lower compared to plain epoxy structure with the decrement in performances of 38% for modulus of elasticity and 61% for tensile strength.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Tensile Properties and Failure Mechanism of 3D Woven Hollow Integrated Sandwich Composites

    NASA Astrophysics Data System (ADS)

    Liu, Chang; Cai, Deng'an; Zhou, Guangming; Lu, Fangzhou

    2017-01-01

    Tensile properties and failure mechanism of 3D woven hollow integrated sandwich composites are investigated experimentally, theoretically and numerically in this paper. Firstly, the tensile properties are obtained by quasi-static tensile tests on the specimens in two principal directions of the sandwich panels, called warp and weft. The experimental results shows that the tensile performances of the warp are better than that of the weft. By observing the broken specimens, it is found that the touch parts between yarns are the main failure regions under tension. Then, a theoretical method is developed to predict the tensile properties. By comparing with the experimental data, the accuracy of the theoretical method is verified. Simultaneously, a finite element model is established to predict the tensile behavior of the composites. The numerical results agree well with the experimental data. Moreover, the simulated progressive damages show that the contact regions in the warp and weft tension are both the initial failure areas.

  4. 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.

  5. Progressive failure of large deformation composites under dynamic tensile loading

    NASA Astrophysics Data System (ADS)

    Xing, Liqun

    The applications of polymer based composite materials in structural components under dynamic loading have increased dramatically. The accurate understanding and modeling of the material mechanical behavior is the basis for the composite structure design and analysis. This research was designed to investigate the progressive failure nature of woven polymer-based composites under dynamic tensile loading conditions. A plain-woven E-glass/vinyl ester composite was selected and a generalized anisotropic material characterization procedure was developed. Off-axial tensile dynamic loading experiments with different strain rates and temperature was conducted. A nonlinear and rate dependent constitutive model used for the polymer-based composites under tensile dynamic tensile loading was constructed. The comparison shows a good match with testing data and a good prediction of stress to failure values. A hybrid method that combined the classical laminate theory with material microstructure analysis was presented to model the large strain to failure phenomenon. A single material parameter failure criteria based on Monkman-Grant concept was built to represent the materials anisotropic and rate dependency natural for tensile loading. And the strength concept based on the material constitution relationship and failure criteria was established to for structure analyses.

  6. Tensile and shear methods for measuring strength of bilayer tablets.

    PubMed

    Chang, Shao-Yu; Li, Jian-Xin; Sun, Changquan Calvin

    2017-05-15

    Both shear and tensile measurement methods have been used to quantify interfacial bonding strength of bilayer tablets. The shear method is more convenient to perform, but reproducible strength data requires careful control of the placement of tablet and contact point for shear force application. Moreover, data obtained from the shear method depend on the orientation of the bilayer tablet. Although more time-consuming to perform, the tensile method yields data that are straightforward to interpret. Thus, the tensile method is preferred in fundamental bilayer tableting research to minimize ambiguity in data interpretation. Using both shear and tensile methods, we measured the mechanical strength of bilayer tablets made of several different layer combinations of lactose and microcrystalline cellulose. We observed a good correlation between strength obtained by the tensile method and carefully conducted shear method. This suggests that the shear method may be used for routine quality test of bilayer tablets during manufacturing because of its speed and convenience, provided a protocol for careful control of the placement of the tablet interface, tablet orientation, and blade is implemented. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Tensile Strength of Natural Fiber Reinforced Polyester Composite

    NASA Astrophysics Data System (ADS)

    Ismail, Al Emran; Awang, Muhd. Khairudin; Sa'at, Mohd Hisham

    2007-05-01

    Nowadays, increasing awareness of replacing synthetic fiber such as glass fiber has emerged due to environmental problems and pollutions. Automotive manufacturers also seek new material especially biodegradable material to be non-load bearing application parts. This present work discussed on the effect of silane treatment on coir fiber reinforced composites. From the results of tensile tests, fibers treated with silane have attained maximum material stiffness. However, to achieve maximum ultimate tensile strength and strain at failure performances, untreated fibers work very well through fiber bridging and internal friction between fiber and polymeric matrix. Scanning electron microscope (SEM) observations have coincided with these results.

  8. 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.

  9. The Effect of Reprocessing on the Tensile Properties of Composites

    NASA Astrophysics Data System (ADS)

    Bodur, Mehmet Safa; Bakkal, Mustafa; Berkalp, Omer Berk; Sadikoglu, Telem Gok

    2011-01-01

    In this study, waste cotton fabric reinforced polymer matrix composite material has been manufactured by a custom made recycling extruder. Composites with different reinforcement ratios as 12,5%wt ( 12,5%wtRPE ) and 25%wt ( 25%wtRPE ) were tested for their mechanical properties such as tensile strength and young's modulus. The material was then granulated down to the size enough to be used in the extrusion process in order to observe the effects of reprocessing. Reprocessing leads to improve Tensile Strength of composite materials and slows down the reduction of tensile strength of polyethylene. It was observed that composite materials were highly affected by the fiber orientation and acts as anisotropic material under the load.

  10. 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.

  11. The tensile fatigue of wire rope: A new approach

    SciTech Connect

    Thorpe, T.W.; Rance, A.

    1983-05-01

    The fatigue behaviour in air and seawater of zinc coated steel wire taken from a 40 mm diameter wire rope has been studied. Seawater had little effect on short term tensile strength but it reduced fatigue life by an amount which increased with increasing mean stress and decreasing test frequency. The application of fretting during fatigue testing resulted in very low endurances, which were similar to those measured in fatigue tests on wire ropes.

  12. 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.

  13. On the tensile strength of insect swarms

    NASA Astrophysics Data System (ADS)

    Ni, Rui; Ouellette, Nicholas T.

    2016-08-01

    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.

  14. Tensile Deformation and Adiabatic Heating in Post-Yield Response of Polycarbonate

    DTIC Science & Technology

    2015-11-01

    measurements performed on the specimen during deformation. In this study, American Society for Testing and Materials tensile dog -bone PC specimens were used...adiabatic heat generation to be quantified. 2. Experiments ASTM D638-1018 standard polymer tensile dog -bone specimens were cut out of 5.75-mm-thick PC

  15. 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.

  16. 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)

  17. 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

  18. Evaluation of tensile strength of surgical synthetic absorbable suture materials: an in vitro study.

    PubMed

    Khiste, Sujeet Vinayak; Ranganath, V; Nichani, Ashish Sham

    2013-06-01

    The purpose of this study was to evaluate the tensile strength of surgical synthetic absorbable sutures over a period of 14 days under simulated oral conditions. Three suture materials (polyglycolic acid [PGA], polyglactin [PG] 910, and poly (glycolide-co-є-caprolactone) [PGC]) were used in 4-0 and 5-0 gauges. 210 suture samples (35 of each material and gauge) were used. All of the samples were tested preimmersion and 1 hour and 1, 3, 7, 10, and 14 days postimmersion. The tensile strength of each suture material and gauge was assessed. The point of breakage and the resorption pattern of the sutures were also assessed. During the first 24 hours of immersion, all 4-0 and 5-0 samples of PGA, PG 910, and PGC maintained their initial tensile strength. At baseline (preimmersion), there was a statistically significant (P<0.001) difference in the tensile strengths between the 4-0 and 5-0 gauge of PGA, PG 910, and PGC. PGA 4-0 showed the highest tensile strength until day 10. At 7 days, all the 4-0 sutures of the three materials had maintained their tensile strength with PGA 4-0 having significantly greater (P=0.003) tensile strength compared to PG. 4-0 sutures are stronger and have greater tensile strength than 5-0 sutures. The PGA 4-0 suture showed the highest tensile strength at the end of day 10.

  19. Evaluation of tensile strength of surgical synthetic absorbable suture materials: an in vitro study

    PubMed Central

    Ranganath, V.; Nichani, Ashish Sham

    2013-01-01

    Purpose The purpose of this study was to evaluate the tensile strength of surgical synthetic absorbable sutures over a period of 14 days under simulated oral conditions. Methods Three suture materials (polyglycolic acid [PGA], polyglactin [PG] 910, and poly (glycolide-co-є-caprolactone) [PGC]) were used in 4-0 and 5-0 gauges. 210 suture samples (35 of each material and gauge) were used. All of the samples were tested preimmersion and 1 hour and 1, 3, 7, 10, and 14 days postimmersion. The tensile strength of each suture material and gauge was assessed. The point of breakage and the resorption pattern of the sutures were also assessed. Results During the first 24 hours of immersion, all 4-0 and 5-0 samples of PGA, PG 910, and PGC maintained their initial tensile strength. At baseline (preimmersion), there was a statistically significant (P<0.001) difference in the tensile strengths between the 4-0 and 5-0 gauge of PGA, PG 910, and PGC. PGA 4-0 showed the highest tensile strength until day 10. At 7 days, all the 4-0 sutures of the three materials had maintained their tensile strength with PGA 4-0 having significantly greater (P=0.003) tensile strength compared to PG. Conclusions 4-0 sutures are stronger and have greater tensile strength than 5-0 sutures. The PGA 4-0 suture showed the highest tensile strength at the end of day 10. PMID:23837127

  20. Mini-tensile specimen application for sheets characterization

    NASA Astrophysics Data System (ADS)

    Džugan, J.; Rund, M.; Prantl, A.; Konopík, P.

    2017-02-01

    There are many cases when there is a shortage of the experimental material for detailed analysis and then small size specimens techniques becomes essential. The current paper deals with investigations of mini-tensile tests (MTT) application to metal sheets characterization. In the case of metal sheets assessment the most common are tensile tests for Lankford parameters and strain hardening determination. As most of the processes are not quasi-static and constant strain rate processes, thus assessment of strain rate hardening is also crucial part of the characterization. Previously developed and verified testing procedure of M-TTs for bulk materials is applied here for steel sheet made of DC01 characterization. Tests under quasi-static and dynamic loading conditions are carried out in order to describe above mentioned properties at room temperature. Accurate strain measurement is carried out with digital image correlation systems and results obtained with M-TTs are going to be confronted with standard size specimens’ results.

  1. Tensile Characterization of FRP Rods for Reinforced Concrete Structures

    NASA Astrophysics Data System (ADS)

    Micelli, F.; Nanni, A.

    2003-07-01

    The application of FRP rods as an internal or external reinforcement in new or damaged concrete structures is based on the development of design equations that take into account the mechanical properties of FRP material systems.The measurement of mechanical characteristics of FRP requires a special anchoring and protocol, since it is well known that these characteristics depend on the direction and content of fibers. In this study, an effective tensile test method is described for the mechanical characterization of FRP rods. Twelve types of glass and carbon FRP specimens with different sizes and surface characteristics were tested to validate the procedure proposed. In all, 79 tensile tests were performed, and the results obtained are discussed in this paper. Recommendations are given for specimen preparation and test setup in order to facilitate the further investigation and standardization of the FRP rods used in civil engineering.

  2. Porosity Defect Remodeling and Tensile Analysis of Cast Steel

    PubMed Central

    Sun, Linfeng; Liao, Ridong; Lu, Wei; Fu, Sibo

    2016-01-01

    Tensile properties on ASTM A216 WCB cast steel with centerline porosity defect were studied with radiographic mapping and finite element remodeling technique. Non-linear elastic and plastic behaviors dependent on porosity were mathematically described by relevant equation sets. According to the ASTM E8 tensile test standard, matrix and defect specimens were machined into two categories by two types of height. After applying radiographic inspection, defect morphologies were mapped to the mid-sections of the finite element models and the porosity fraction fields had been generated with interpolation method. ABAQUS input parameters were confirmed by trial simulations to the matrix specimen and comparison with experimental outcomes. Fine agreements of the result curves between simulations and experiments could be observed, and predicted positions of the tensile fracture were found to be in accordance with the tests. Chord modulus was used to obtain the equivalent elastic stiffness because of the non-linear features. The results showed that elongation was the most influenced term to the defect cast steel, compared with elastic stiffness and yield stress. Additional visual explanations on the tensile fracture caused by void propagation were also given by the result contours at different mechanical stages, including distributions of Mises stress and plastic strain. PMID:28787919

  3. Tensile experiments and SEM fractography on bovine subchondral bone.

    PubMed

    Braidotti, P; Bemporad, E; D'Alessio, T; Sciuto, S A; Stagni, L

    2000-09-01

    Subchondral bone undecalcified samples, extracted from bovine femoral heads, are subjected to a direct tensile load. The Young's modulus of each sample is determined from repeated tests within the elastic limit. In a last test, the tensile load is increased up to the specimen failure, determining the ultimate tensile strength. The investigation is performed on both dry and wet specimens. The measured Young's modulus for dry samples is 10.3+/-2.5GPa, while that of wet samples is 3.5+/-1.2GPa. The ultimate tensile strengths are 36+/-10 and 30+/-7.5MPa for dry and wet specimens, respectively. SEM micrographs of failure surfaces show characteristic lamellar bone structures, with lamellae composed of calcified collagen fibers. Rudimentary osteon-like structures are also observed. Failure surfaces of wet samples show a marked fiber pull-out, while delamination predominates in dry samples. The obtained results are interpreted on the basis of the deformation mechanisms typical of fiber-reinforced laminated composite materials.

  4. Ultra-high temperature tensile properties of ODS steel claddings under severe accident conditions

    NASA Astrophysics Data System (ADS)

    Yano, Y.; Tanno, T.; Oka, H.; Ohtsuka, S.; Inoue, T.; Kato, S.; Furukawa, T.; Uwaba, T.; Kaito, T.; Ukai, S.; Oono, N.; Kimura, A.; Hayashi, S.; Torimaru, T.

    2017-04-01

    Ultra-high temperature ring tensile tests were performed to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions with temperatures ranging from room temperature to 1400 °C which is close to the melting point of core materials. The experimental results showed that the tensile strength of 9Cr-ODS steel claddings was highest in the core materials at ultra-high temperatures of 900-1200 °C, but there was significant degradation in the tensile strength of 9Cr-ODS steel claddings above 1200 °C. This degradation was attributed to grain boundary sliding deformation with γ/δ transformation, which is associated with reduced ductility. By contrast, the tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 °C, unlike the other tested materials.

  5. Surfactant effects on soil aggregate tensile strength

    USDA-ARS?s Scientific Manuscript database

    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...

  6. 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 leaf...

  7. 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 leaf...

  8. 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 leaf...

  9. 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 leaf...

  10. 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...

  11. 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.

  12. The Tensile Behavior of High-Strength Carbon Fibers.

    PubMed

    Langston, Tye

    2016-08-01

    Carbon fibers exhibit exceptional properties such as high stiffness and specific strength, making them excellent reinforcements for composite materials. However, it is difficult to directly measure their tensile properties and estimates are often obtained by tensioning fiber bundles or composites. While these macro scale tests are informative for composite design, their results differ from that of direct testing of individual fibers. Furthermore, carbon filament strength also depends on other variables, including the test length, actual fiber diameter, and material flaw distribution. Single fiber tensile testing was performed on high-strength carbon fibers to determine the load and strain at failure. Scanning electron microscopy was also conducted to evaluate the fiber surface morphology and precisely measure each fiber's diameter. Fiber strength was found to depend on the test gage length and in an effort to better understand the overall expected performance of these fibers at various lengths, statistical weak link scaling was performed. In addition, the true Young's modulus was also determined by taking the system compliance into account. It was found that all properties (tensile strength, strain to failure, and Young's modulus) matched very well with the manufacturers' reported values at 20 mm gage lengths, but deviated significantly at other lengths.

  13. Strain distribution in Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass investigated by in situ tensile tests under synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Stoica, M.; Das, J.; Bednarcik, J.; Franz, H.; Mattern, N.; Wang, W. H.; Eckert, J.

    2008-07-01

    We report on the evolution of the atomic-scale strain tensor of ductile Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass under tensile loading by using x-ray synchrotron radiation. The same kind of samples was previously investigated under compressive loading and revealed yielding at 1690 MPa together with large deformability of up to 160% strain. In tension the samples fracture at a lower stress, 1500 MPa, with no sign of yielding or plastic deformation. With no macroplasticity observed under tension, large differences in the elastic constants obtained from the strain tensor and from ultrasonic sound velocity measurements are revealed. This paper presents in detail the measuring procedure as well as the calculation of the tensile tensor and pair distribution functions of Zr64.13Cu15.75Ni10.12Al10 at different stages of deformation. The results are discussed in comparison with other reported data obtained from x-ray diffraction measurements using synchrotron radiation.

  14. 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.

  15. The Effect of Gap Angle on Tensile Strength of Preceramic Base Metal Solder Joints.

    PubMed

    Fattahi, Farnaz; Hashemi Ardakani, Zahra; Hashemi Ardakani, Maryam

    2015-12-01

    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. The purpose of this study was to evaluate the effect of gap angle on the tensile strength of base metal solder joints. 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). 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). 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Evaluation of the tensile strength of the human ureter--preliminary results.

    PubMed

    Shilo, Yaniv; Pichamuthu, Joseph E; Averch, Timothy D; Vorp, David A

    2014-12-01

    Ureteral injuries such as avulsion are directly related to mechanical damage of the ureter. Understanding the tensile strength of this tissue may assist in prevention of iatrogenic injuries. Few published studies have looked at the mechanical properties of the animal ureter and, of those, none has determined the tensile strength of the human ureter. Therefore, the purpose of this work was to determine the tensile strength of the human ureter. We harvested 11 human proximal ureters from patients who were undergoing nephrectomy for either kidney tumors or nonfunctioning kidney. The specimens were then cut into multiple circumferentially and longitudinally oriented tissue strips for tensile testing. Strips were uniaxially stretched to failure in a tensile testing machine. The corresponding force and displacement were recorded. Finally, stress at failure was noted as the tensile strength of the sample. Circumferential tensile strength was also compared in the proximal and distal regions of the specimens. The tensile strength of the ureter in circumferential and longitudinal orientations was found to be 457.52±33.74 Ncm(-2) and 902.43±122.08 Ncm(-2), respectively (P<0.001). The circumferential strength in the proximal portion of the ureter was 409.89±35.13 Ncm(-2) in comparison with 502.89±55.85 Ncm(-2) in the distal portion (P=0.08). The circumferential tensile strength of the ureter was found to be significantly lower than the longitudinal strength. Circumferential tensile strength was also lower with more proximal parts of the ureter. This information may be important for the design of "intelligent" devices and simulators to prevent complications.

  2. Evaluation of the tensile strength of the human ureter - Preliminary results.

    PubMed

    Shilo, Yaniv; Pichamuthu, Joseph E; Averch, Timothy D; Vorp, David A

    2014-09-15

    Introduction: Ureteral injuries such as avulsion are directly related to mechanical damage of the ureter. Understanding the tensile strength of this tissue may assist in prevention of iatrogenic injuries. Few published studies have looked at the mechanical properties of the animal ureter, and of those none have determined the tensile strength of the human ureter. Therefore, the purpose of this work was to determine the tensile strength of the human ureter. Materials and Methods: We harvested 11 human proximal ureters from patients who were undergoing nephrectomy for either kidney tumors or non-functioning kidney. The specimens were then cut into multiple circumferentially and longitudinally-oriented tissue strips for tensile testing. Strips were uniaxially stretched to failure in a tensile testing machine. The corresponding force and displacement were recorded. Finally, stress at failure was noted as the tensile strength of the sample. Circumferential tensile strength was also compared in the proximal and distal regions of the specimens. Results: The tensile strength of the ureter in circumferential and longitudinal orientations was found to be 457.52±33.74 Ncm-2 and 902.43±122.08 Ncm-2, respectively (p<0.001). The circumferential strength in the proximal portion of the ureter was 409.89±35.13 Ncm-2 in comparison to 502.89±55.85 Ncm-2 in the distal portion (p=0.08). Conclusions: The circumferential tensile strength of the ureter was found to be significantly lower than the longitudinal strength. Circumferential tensile strength was also lower with more proximal parts of the ureter. This information may be important for the design of "intelligent" devices and simulators in order to prevent complications.

  3. Are tensile and compressive Young's moduli of compact bone different?

    PubMed

    Barak, Meir M; Currey, John D; Weiner, Steve; Shahar, Ron

    2009-01-01

    This study examines the question of whether the stiffness (Young's modulus) of secondary osteonal cortical bone is different in compression and tension. Electronic speckle pattern interferometry (ESPI) is used to measure concurrently the compressive and tensile strains in cortical bone beams tested in bending. ESPI is a non-contact method of measuring surface deformations over the entire region of interest of a specimen, tested wet. The measured strain distributions across the beam, and the determination of the location of the neutral axis, demonstrate in a statistically-robust way that the tensile Young's modulus is slightly (6%), but significantly greater than that of the compressive Young's modulus. It is also shown that within a relatively small bone specimen there are considerable variations in the modulus, presumably caused by structural inhomogeneities.

  4. 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.

  5. Statistical data for the tensile properties of natural fibre composites.

    PubMed

    Torres, J P; Vandi, L-J; Veidt, M; Heiztmann, M T

    2017-06-01

    This article features a large statistical database on the tensile properties of natural fibre reinforced composite laminates. The data presented here corresponds to a comprehensive experimental testing program of several composite systems including: different material constituents (epoxy and vinyl ester resins; flax, jute and carbon fibres), different fibre configurations (short-fibre mats, unidirectional, and plain, twill and satin woven fabrics) and different fibre orientations (0°, 90°, and [0,90] angle plies). For each material, ~50 specimens were tested under uniaxial tensile loading. Here, we provide the complete set of stress-strain curves together with the statistical distributions of their calculated elastic modulus, strength and failure strain. The data is also provided as support material for the research article: "The mechanical properties of natural fibre composite laminates: A statistical study" [1].

  6. 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.

  7. Tensile Properties of Epoxy Composites Reinforced with Continuous PALF Fibers

    NASA Astrophysics Data System (ADS)

    Glória, Gabriel O.; Altoé, Giulio R.; Moraes, Ygor M.; Loyola, Rômulo L.; Margem, Frederico M.; Monteiro, Sergio N.

    The tensile properties of DGEBA/TETA epoxy matrix composites reinforced with different amounts of PALF fibers were evaluated. Composites reinforced with up to 30% in volume of long, continuous and aligned PALF fibers were tested in an Instron machine at room temperature. The fracture was analyzed by SEM. This one revealed a weak fiber/matrix interface, which could be responsible for the performance of some properties. The results showed significant changes in the mechanical properties with the amount of PALF fibers.

  8. Determination of Tensile Properties of Polymers at High Strain Rates

    NASA Astrophysics Data System (ADS)

    Reiter, M.; Major, Z.

    2010-06-01

    In the field of high rate testing of polymers the measured properties are highly dependent on the applied methodology. Hence, the test setup as whole but in particular also the geometrical type of specimen plays a decisive role. The widely used standard for the determination of tensile properties of polymers (ISO527-2) was extended by a novel standard (ISO18872:2007), which is targeted on the determination of tensile properties at high strain rates. In this standard also a novel specimen shape is proposed. Hand in hand with the introduction of new specimen geometry the question of comparability arises. To point out the differences in stress-strain response of the ISO18872 specimen and the ISO527-2 multipurpose specimen tensile tests over a wide loading rate range were conducted in this paper. A digital image correlation system in combination with a high speed camera was used to characterize the local material behaviour. Different parameters like nominal stress, true stress, nominal strain, true strain as well as volumetric strain were determined and used to compare the two specimen geometries.

  9. 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.

  10. Comparison of Changes in Tensile Strength in Three Different Flexible Epidural Catheters Under Various Conditions.

    PubMed

    Gonzalez Fiol, Antonio; Horvath, Robert; Schoenberg, Catherine; Ahmed, Nubyra; Dhar, Sunil Kumar; Le, Vanny

    2016-07-01

    Rarely, epidural catheters may fracture upon removal or insertion. Understanding some of the mechanical properties of epidural catheters, such as their tensile strength and how external factors (including temperature) can influence their strength, will aid physicians in making decisions if faced with an entrapped catheter. In the present study, we evaluated the impact in tensile strength when catheters are exposed to 37 ± 1°C, after the removal of the inner metal coil and after the injection of sterile saline through the catheter. We analyzed the tensile strength of a total of 120 catheters (19-gauge) from 3 different brands and materials. The reinforced epidural catheters were affixed to opposing, specially designed tensile test fixtures and then installed in an Applied Test System tensile test apparatus. We evaluated the strength of 10 catheters from different brands and materials for each of the following variables: at room temperature (control group), after the removal of the inner wire present in all the flexible catheters tested, injection of normal saline, and at 37 ± 1°C. When compared with their control groups, the Arrow catheter (2.85 kg) was shown to be superior to B-Braun (2.17 kg; P < 0.0001) and Smith catheters (2.33 kg; P < 0.0005). No statistical difference was noted between the Smith and B-Braun catheters (P = 0.39). When comparing catheters after wire removal against their respective control group, no statistical difference was noted. A decrease in tensile strength was noted in the B-Braun catheters (1.53 kg) when tested at 37°C (P ≤ 0.0001). In contrast, the Smith and the Arrow catheters did not show a statistically significant change when tested at 37°C (P = 1.0 and P = 0.063, respectively). After the injection of normal saline, the Arrow (2.33 kg) and the B-Braun (1.58 kg) catheters showed a decrease in tensile strength (P = 0.0010 and P = 0.0001, respectively). The current recommendation of injecting saline through an entrapped

  11. 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.

  12. 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.

  13. 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.

  14. Tensile Strength of Epoxy Composites Reinforced with Fique Fibers

    NASA Astrophysics Data System (ADS)

    Altoé, Giulio Rodrigues; Netto, Pedro Amoy; Teles, Maria Carolina Andrade; Borges, Luiz Gustavo Xavier; Margem, Frederico Muylaert; Monteiro, Sergio Neves

    Environmentally friendly composites, made from natural fibers, are among the most investigated and applied today. Natural fibers have showed advantages, such as, flexibility and toughness, if compared with synthetic fibers. This work investigates the tensile strength of epoxy composites reinforced with Fique fibers. The Fique fiber was extracted from Fique leaf presents some significant characteristic, but until now only few studies on Fique fiber were performed. Composites reinforced with up to 30% in volume of long, continuous and aligned Fique fibers were tested in an Instron machine at room temperature. The incorporation of Fique fibers increases the tensile strength of the composite. After fracture the specimens were analyzed by a SEM (scanning electron microscope).

  15. Cavitation mechanisms during tensile creep of an advanced silicon nitride

    SciTech Connect

    Lofaj, F.; Okada, A.; Usami, H.

    1996-12-31

    Creep cavitation was investigated by electron microscopic methods after tensile creep tests of a self-reinforced silicon nitride conducted at temperatures ranging from 1250 to 1400{degrees}C. Fast and intensive cavitation in the amorphous secondary phase and slow growth of cavities inside the large silicon nitride grains were observed. Two basic types of cavities in glassy boundary phase were found; rounded cavities on the facets of large grains and irregular cavities in pockets among the matrix grains. A driving force for cavitation in boundary phase on large grain facets is concluded to be local tensile stress on local irregularities of facets produced on the interfaces between large grains and finer matrix grains during grain boundary sliding (GBS). Dilatant hydrostatic tensile stresses generated in a matrix due to GBS were thought to be responsible for cavitation in multigrain junctions. Small cavities formed on the facets and large cavities penetrating through the whole large grains of silicon nitride were found after long-term tests. The stresses transferred from matrix to large grains are suggested as a driving force for slow growth of small cavities on the facets and their later penetration inside the large silicon nitride grains. Basic cavitation mechanisms in amorphous phase are thought to be GBS and viscous flow while solution-precipitation is responsible for cavity growth in large silicon nitride grains.

  16. 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

  17. Correlation between flexural and indirect tensile strength of resin composite cements.

    PubMed

    Cassina, Gianluca; Fischer, Jens; Rohr, Nadja

    2016-11-04

    To evaluate a potential correlation between flexural strength and indirect tensile strength in assessing the mechanical strength of resin composite cements. Flexural strength (n = 5) and indirect tensile strength (n = 5) of 7 resin composite cements (RelyX Unicem 2 Automix [RXU], Panavia SA [PSA], Clearfil SA [CSA], Panavia F2.0 [PF2], Multilink Implant [MLI], DuoCem [DCM], Panavia 21 [P21]) were determined. Specimens were either auto-polymerized or dual-cured (except P21) and stored in water at 37 °C for 1 day prior to measurement. Flexural and indirect tensile strength of 4 cements (RXU, PSA, PF2, MLI) was additionally measured directly after curing and after 96 h water storage at 37 °C. Except for PF2, dual-cured specimens achieved higher flexural strength than auto-polymerized specimens. In the indirect tensile strength test differences in auto-polymerized and dual-cured specimens were only detected for RXU and DCM. A general non-linear correlation was found between flexural and indirect tensile strength values. However, strength values of auto-polymerized and dual-cured specimens did not generally correlate. Flexural strength and indirect tensile strength of resin composite cements are correlated. At high strength values the indirect tensile test is less sensitive than the flexural test. The results suggest that the indirect tensile test may only be recommended as a screening test especially for low or medium strength resin composite cements.

  18. Infliximab treatment reduces tensile strength in intestinal anastomosis.

    PubMed

    Jensen, Jonas Sanberg; Petersen, Nacie Bello; Biagini, Matteo; Bollen, Peter; Qvist, Niels

    2015-01-01

    The antitumor necrosis factor (infliximab [IFX]) has gained widespread use in the treatment of inflammatory bowel disease. However, several patients must undergo surgical treatment due to treatment failure and there is a potential risk that preoperative IFX treatment may have a negative effect on the healing process in intestinal anastomosis. The objective of this study was to examine the effect of repeated IFX treatment on anastomotic strength and degree of inflammation in the anastomotic line in the small intestine of rabbits. Thirty-two rabbits were randomized (2:1) to receive either repeated IFX treatment or placebo. On day 15, three separate end-to-end anastomoses were performed on the jejunum. On postoperative day 5, tensile strength and bursting pressure for the anastomoses were tested and histologic changes examined. We found a significantly reduced tensile strength in the IFX group (1.94 ± 0.44 N) compared with the placebo group (3.33 ± 0.39 N), (P < 0.001). Calculation of Spearman correlation coefficients showed a positive significant correlation between minimal tensile strength and serum values of IFX (coefficient = -0.63; P = 0.003) as well as number of sutures in the tested anastomosis (coefficient = 0.51; P = 0.024). The general histologic score was significantly higher in the placebo group (5.00 ± 1.26 versus 3.31 ± 1.65, P = 0.03). Repeated high-dose IFX treatment reduces tensile strength significantly in rabbits and should be investigated further as a potential risk factor of anastomotic dehiscence in inflammatory bowel disease surgery. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. 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.

  20. The Dynamic Tensile Behavior of Railway Wheel Steel at High Strain Rates

    NASA Astrophysics Data System (ADS)

    Jing, Lin; Han, Liangliang; Zhao, Longmao; Zhang, Ying

    2016-11-01

    The dynamic tensile tests on D1 railway wheel steel at high strain rates were conducted using a split Hopkinson tensile bar (SHTB) apparatus, compared to quasi-static tests. Three different types of specimens, which were machined from three different positions (i.e., the rim, web and hub) of a railway wheel, were prepared and examined. The rim specimens were checked to have a higher yield stress and ultimate tensile strength than those web and hub specimens under both quasi-static and dynamic loadings, and the railway wheel steel was demonstrated to be strain rate dependent in dynamic tension. The dynamic tensile fracture surfaces of all the wheel steel specimens are cup-cone-shaped morphology on a macroscopic scale and with the quasi-ductile fracture features on the microscopic scale.

  1. Effect of ceramic surface treatment on tensile bond strength to a resin cement.

    PubMed

    Della Bona, Alvaro; Anusavice, Kenneth J; Hood, James A A

    2002-01-01

    The objective of this study was to test the following hypotheses: (1) hydrofluoric acid (HF)-treated ceramic surfaces produce the highest tensile bond strength to resin cements, independent of the ceramic microstructure and composition; and (2) the tensile bond strength test is appropriate for analysis of interfacial adhesion for ceramic-bonded-to-resin systems. Ceramic specimens were polished with 1-micron alumina abrasive and divided into four groups of 10 specimens for each of seven ceramic types. One of the following surface treatments was applied: (1) 10% ammonium bifluoride (ABF) for 1 minute; (2) 9.6% HF for 2 minutes; (3) 4% acidulated phosphate fluoride (APF) for 2 minutes; and (4) a silane coupling agent. The surface-treated areas were coated with an adhesive resin and bonded to a resin cement. Specimens were loaded to failure in tension using a testing machine. Tensile bond strength data were statistically analyzed, and fracture surfaces were examined to determine the mode of failure. Silane-treated surfaces showed statistically higher mean tensile bond strength values than surfaces treated with any etchant (HF, ABF, APF). HF produced statistically higher mean tensile bond strengths than ABF and APF. All failures occurred in the adhesion zone. The tensile bond strength test is adequate for analysis of the adhesive zone of resin-ceramic systems. The chemical adhesion produced by silane promoted higher mean bond strength values than the micromechanical retention produced by any etchant for the resin-ceramic systems used in this study.

  2. Soil Stabilization: A Durability Test for Stabilized Soils

    DTIC Science & Technology

    tensile strength at the surface of test specimens (slabs) subjected to laboratory cycles of weathering. This test, called the Durability Tensile Test , is...have been shown elsewhere to cause a loss in effective cohesion, also result in a loss in tensile strength. Therefore the Durability Tensile Test appears

  3. 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.

  4. 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.

  5. STATUS OF IN-REACTOR TENSILE STRAINING OF PURE COPPER AT A CONSTANT STRAIN RATE

    SciTech Connect

    Edwards, Danny J.; Singh, Bachu N.; Tahtinen, S.; Moilanen, P.; Jacquet, P.; Dekeyser, J.

    2003-09-03

    Annealed tensile samples of pure copper were irradiated in the fission reactor BR-2 in Mol, Belgium at 90 degrees C with a damage rate of 0.00000006 dpa/sec. The tensile specimens were a sheet-type specimen with a 3-mm gage width and a gage length of 7 mm. The first experiment involved two specimens, one of which was irradiated with no load to provide a comparative specimen to the other specimen, which was loaded at a constant strain rate of 0.00000013 1/s. The uniaxial tensile load was applied 4 hrs after the irradiation rig was inserted into the reactor core. This corresponded to a total displacement damage of 0.00086 dpa accumulated before the tensile test was started. The tensile test was considered complete once the load began rapidly falling and reached 100 MPa, at which level the test was stopped and the load quickly reduced to zero to leave the specimen intact. For these test conditions the specimen reached a total plastic strain of approximately 13 percent when the test was stopped, considerably less than that of unirradiated pure copper tested under the same strain rate, which was on the order of 50 percent total elongation. The second experiment involved two samples irradiated under identical irradiation and test conditions, but in this case the tensile load was not applied until a total dose of 0.01 dpa (approximately 50 hours after insertion into the reactor core) was reached. Once the load was applied, the stress immediately climbed to approximately 150 MPa with little plastic strain, followed by a small yield drop and work hardening up to a maximum stress of approximately 200 MPa. As in the first experiment, the tensile test was stopped when the load began decreasing and reached a level of 100 MPa.

  6. 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.

  7. 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.

  8. Tensile Deformation and Morphological Evolution of Precise Acid Copolymers

    NASA Astrophysics Data System (ADS)

    Middleton, Luri Robert; Szewczyk, Steve; Schwartz, Eric; Azoulay, Jason; Murtagh, Dustin; Cordaro, Joseph; Wagener, Kenneth; Winey, Karen

    2015-03-01

    Acid- and ion-containing polymers have specific interactions that produce complex and hierarchical morphologies that provide tunable mechanical properties. We report tensile testing and in situ x-ray scattering measurements of a homologous series of precise poly(ethylene-co-acrylic acid) copolymers (pxAA). Upon variation of the number of backbone carbons (x = 9, 15, 21) between pendant acrylic acid groups along the linear polyethylene chain, these materials exhibit pronounced changes in both their tensile properties as well as their morphological evolution during deformation. The hierarchical layered acid aggregate structure coincides with the onset of a strain hardening mechanism and was observed in both a semi-crystalline sample (p21AA) as well as an amorphous sample (p15AA). The polymer with the shortest spacing between acid groups (p9AA) maintains a liquid-like distribution of acid aggregates during deformation, exhibiting low tensile strength which we attribute to facile acid exchange between acid aggregates during deformation. Our results indicate that the formation of the hierarchical layered structure, which coincides with polymer strain-hardening regime, originates from the associating acid groups cooperatively preventing disentanglement. NSF-DMR-1103858.

  9. 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.

  10. Dentin adhesive tensile strength after Nd:YAG laser application

    NASA Astrophysics Data System (ADS)

    Lizarelli, Rosane F. Z.; Miranda, Walter G., Jr.; Eduardo, Carlos d. P.

    1999-05-01

    The authors evaluated, in vitro, the tensile strength of a hydrophilic adhesive on dentin surface, with and without previous treatment with high power Nd:YAG laser. Power of 1.0 W and 2.0 W with respective frequencies of 25 Hz and 50 Hz were used. Thirteen human extracted molars were prepared and randomly separated in five groups: GI, Nd:YAG laser with 1.0 W plus SBMPP (3M) adhesive system; GII, laser with 2.0 W, plus adhesive system; GIII, laser with 1.0 W; GIV, laser with 2.0 W; GV, adhesive system to treat dentin surface. To each group five samples with a composite bottom each, totalling in 25 samples, which were kept in distilled water, by 37°C, during 30 days. After that, thermal cycling was applied. After this period, the samples were submitted the tensile strength test to evaluate the necessary threshold of power to break up the adhesive bond of composite button from dentin surface. The statistical evaluation was done through variance analysis. Results showed that the values of tensile strength of the GV (26.4 kgf/cm2) were better than GI (4.6 kgf/cm2) which was the best laser group: GIII (2.4 kgf/cm2); GII (1.7 kgf/cm2) and GIV (1.2 kgf/cm2).

  11. 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

  12. Comparative evaluation of tensile strength of Gutta-percha cones with a herbal disinfectant.

    PubMed

    Mahali, Raghunandhan Raju; Dola, Binoy; Tanikonda, Rambabu; Peddireddi, Suresh

    2015-01-01

    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). 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. 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. Ninety percent Aloe vera gel as a disinfectant does not alter the tensile strength of GP cones.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Effect of Stitching on the Tensile Mechanical Property of Empty Fruit Bunch Oil Palm Fiber Reinforced Epoxy Composites

    NASA Astrophysics Data System (ADS)

    Ghazilan, A. L. Ahmad; Mokhtar, H.; Shaik Dawood, M. S. I.; Aminanda, Y.; Ali, J. S. Mohamed

    2017-03-01

    Stitching has proven to be an effective reinforcement for improving through-thickness (out-of-plane) mechanical properties with the incorporation of z-direction reinforcements of synthestic fiber. There are drawbacks to stitching as it may cause focal stress concentration, and fiber misalignment and breakage, but at the same time, it can also improve the tensile performance of the composite. Tensile properties, such as tensile strength and modulus of elasticity, were obtained from tensile tests performed on both stitched and unstitched oil palm fiber composites as per ASTM D638 specifications using Universal Testing Machine INSTRON 5582. The test results indicated that stitching natural, short, untreated and random empty fruit bunch oil palm fiber reinforced epoxy composites improve the tensile strength and elastic modulus due to the increase in matrix volume percentage and additional tensional resistance.

  19. 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.

  20. Dynamic yield and tensile strengths of spark plasma sintered alumina

    NASA Astrophysics Data System (ADS)

    Girlitsky, I.; Zaretsky, E.; Kalabukhov, S.; Dariel, M.; Frage, N.

    2014-05-01

    Fully dense alumina samples with 0.6 μm grain size were produced from alumina powder using Spark Plasma Sintering and tested in two types of VISAR-instrumented planar impact tests. In the tests of the first type the samples of 0.28 to 6-mm thickness were loaded by 1-mm tungsten impactors accelerated up to a velocity of about 1 km/s. These tests were aimed to study the Hugoniot elastic limit (HEL) of the SPS-processed alumina and the decay of the elastic precursor wave with propagation distance. In the second type of test the samples of ~3-mm thickness were loaded by 1-mm copper impactors accelerated up to velocities 100-1000 m/s. These tests were aimed to study the dynamic tensile (spall) strength of the alumina. The data on tensile fracture of the alumina demonstrate a monotonic decline of the spall strength with the amplitude of the loading stress pulse. The data on the decay of the elastic precursor wave allows for determining the rates of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of shock-induced inelastic deformation and, thus, to derive some conclusions concerning the mechanisms responsible of the deformation.

  1. Dynamic yield and tensile strengths of spark plasma sintered alumina

    NASA Astrophysics Data System (ADS)

    Girlitsky, Inna; Zaretsky, E.; Kalabukhov, S.; Dariel, M.; Frage, N.

    2013-06-01

    Fully dense alumina samples with 0.6- μ grain size were produced from alumina powder using Spark Plasma Sintering and tested in two types of VISAR-instrumented planar impact tests.. In the tests of the first type the samples of 0.28 to 6-mm thickness were loaded by 1-mm tungsten impactors accelerated up to velocity of about 1 km/s. These tests were aimed to study of the Hugoniot elastic limit (HEL) of the SPS-processed alumina and the decay of the elastic precursor wave with the propagation distance. In the second type of the tests the samples of ~ 3-mm thickness were loaded by 1-mm copper impactors accelerated up to velocities 100-1000 m/s was. These tests were aimed to the study of the dynamic tensile (spall) strength of the alumina. The data on the decay of the elastic precursor wave allow determining the rates of the irreversible (inelastic) strains in the SPS-processed alumina at the initial stages of the shock-induced plastic deformation and, thus, to derive some conclusions concerning the mechanisms responsible of the deformation. The data on the tensile fracture of the alumina demonstrate a monotonous decline of the spall strength with the amplitude of the loading stress pulse.

  2. Effects of soldering methods on tensile strength of a gold-palladium metal ceramic alloy.

    PubMed

    Ghadhanfari, Husain A; Khajah, Hasan M; Monaco, Edward A; Kim, Hyeongil

    2014-10-01

    The tensile strength obtained by conventional postceramic application soldering and laser postceramic welding may require more energy than microwave postceramic soldering, which could provide similar tensile strength values. The purpose of the study was to compare the tensile strength obtained by microwave postceramic soldering, conventional postceramic soldering, and laser postceramic welding. A gold-palladium metal ceramic alloy and gold-based solder were used in this study. Twenty-seven wax specimens were cast in gold-palladium noble metal and divided into 4 groups: laser welding with a specific postfiller noble metal, microwave soldering with a postceramic solder, conventional soldering with the same postceramic solder used in the microwave soldering group, and a nonsectioned control group. All the specimens were heat treated to simulate a normal porcelain sintering sequence. An Instron Universal Testing Machine was used to measure the tensile strength for the 4 groups. The means were analyzed statistically with 1-way ANOVA. The surface and fracture sites of the specimens were subjectively evaluated for fracture type and porosities by using a scanning electron microscope. The mean (standard deviation) ultimate tensile strength values were as follows: nonsectioned control 818 ±30 MPa, microwave 516 ±34 MPa, conventional 454 ±37 MPa, and laser weld 191 ±39 MPa. A 1-way ANOVA showed a significant difference in ultimate tensile strength among the groups (F3,23=334.5; P<.001). Follow-up multiple comparisons showed a significant difference among all the groups. Microwave soldering resulted in a higher tensile strength for gold and palladium noble metals than either conventional soldering or laser welding. Conventional soldering resulted in a higher tensile strength than laser welding. Under the experimental conditions described, either microwave or conventional postceramic soldering would appear to satisfy clinical requirements related to tensile strength

  3. 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.

  4. Tensile strength and fracture toughness of particulate SiC-2124 aluminum composites

    SciTech Connect

    Kumar, D.; Murty, G.S.; Vaidya, M.L.

    1994-12-31

    The 2124 Al-SiC composites having 10 and 20 vol.% of SiC particulates with sizes of 0.25 {mu}m and 17 {mu}m were processed by the P/M route followed by hot extrusion. Their tensile properties and fracture toughness were assessed in the peak-aged (T6) condition by standard and notch tensile tests. All the composites exhibit higher yield strength and lower ductility than the unreinforced alloy. The finer reinforcements (0.25 {mu}m) are more effective in this regard than the coarser ones (17 {mu}m). The maximum increase in yield strength is {approximately}40% over the matrix alloy in the composite with 0.25 {mu}m and 20 vol.% SiCp. While the tensile strength of composites with fine SiCp is higher than that of the unreinforced alloy, marginally lower tensile strength is observed in those with coarse SiCp. The effect of volume fraction on tensile properties is however minor in both the composites with fine and coarse SiCp. The observed increase in yield strength of composites relative to the unreinforced matrix is assessed in terms of direct load sharing by reinforcements and the indirect effects of particles in modifying the matrix grain size and dislocation density. The notch tensile strength, notch yield strength ratio and fracture toughness evaluated from notch tensile tests are lower than those of the unreinforced alloy. The critical stress intensity factor (K{sub Q}) for fracture of composites evaluated by the notch tensile test compares favorably with that based on plastic zone correction (K{sub IC}).

  5. 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.

  6. 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.

  7. 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.

  8. Tensile and compressive failure modes of laminated composites loaded by fatigue with different mean stress

    NASA Technical Reports Server (NTRS)

    Rotem, Assa

    1990-01-01

    Laminated composite materials tend to fail differently under tensile or compressive load. Under tension, the material accumulates cracks and fiber fractures, while under compression, the material delaminates and buckles. Tensile-compressive fatigue may cause either of these failure modes depending on the specific damage occurring in the laminate. This damage depends on the stress ratio of the fatigue loading. Analysis of the fatigue behavior of the composite laminate under tension-tension, compression-compression, and tension-compression had led to the development of a fatigue envelope presentation of the failure behavior. This envelope indicates the specific failure mode for any stress ratio and number of loading cycles. The construction of the fatigue envelope is based on the applied stress-cycles to failure (S-N) curves of both tensile-tensile and compressive-compressive fatigue. Test results are presented to verify the theoretical analysis.

  9. 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.

  10. 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.

  11. 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.

  12. An Experimental Study of Dynamic Tensile Failure of Rocks Subjected to Hydrostatic Confinement

    NASA Astrophysics Data System (ADS)

    Wu, Bangbiao; Yao, Wei; Xia, Kaiwen

    2016-10-01

    It is critical to understand the dynamic tensile failure of confined rocks in many rock engineering applications, such as underground blasting in mining projects. To simulate the in situ stress state of underground rocks, a modified split Hopkinson pressure bar system is utilized to load Brazilian disc (BD) samples hydrostatically, and then exert dynamic load to the sample by impacting the striker on the incident bar. The pulse shaper technique is used to generate a slowly rising stress wave to facilitate the dynamic force balance in the tests. Five groups of Laurentian granite BD samples (with static BD tensile strength of 12.8 MPa) under the hydrostatic confinement of 0, 5, 10, 15, and 20 MPa were tested with different loading rates. The result shows that the dynamic tensile strength increases with the hydrostatic confining pressure. It is also observed that under the same hydrostatic pressure, the dynamic tensile strength increases with the loading rate, revealing the so-called rate dependency for engineering materials. Furthermore, the increment of the tensile strength decreases with the hydrostatic confinement, which resembles the static tensile behavior of rock under confining pressure, as reported in the literature. The recovered samples are examined using X-ray micro-computed tomography method and the observed crack pattern is consistent with the experimental result.

  13. 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.

  14. Tensile properties of a ZnS nanowire determined with a nano-manipulator and force sensor

    NASA Astrophysics Data System (ADS)

    Jang, Hoon-Sik; Nahm, Seung Hoon; Lee, Hak Joo; Kim, Jung Han; Oh, Kyu Hwan

    2012-08-01

    Tensile tests of an individual ZnS nanowire with a cubic structure were performed with a nano-manipulator inside a scanning electron microscope (SEM). To perform the tensile test of ZnS nanowires, a mechanical testing system was installed in the SEM. A nano-manipulator was set up in the SEM, and a cantilever force sensor was mounted on the nano-manipulator. The force sensor could be controlled with the nano-manipulator. The ZnS nanowires were dispersed on the transmission electron microscope (TEM) grid; then, the ends of the ZnS nanowires were welded to the TEM grid and the tip of force sensor by exposing them to the E-beam of the SEM. The tensile tests of the ZnS nanowires were performed by controlling the nano-manipulator in the SEM. The load response during the tensile tests was obtained with a force sensor. The strain-stress curve was obtained from the tensile load-displacement curve after the tensile test. The tensile strengths for nanowires 1, 2, and 3 were 364.7 ± 5.2, 146.2 ± 5.2, and 234.4 ± 5.2 MPa, respectively, and the elastic moduli for nanowires 1, 2, and 3 were 39 ± 5.2, 33.4 ± 5.2, and 37.4 ± 5.2 GPa, respectively.

  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. Novel in situ device for investigating the tensile and fatigue behaviors of bulk materials.

    PubMed

    Ma, Zhichao; Zhao, Hongwei; Li, Qinchao; Wang, Kaiting; Zhou, Xiaoqin; Hu, Xiaoli; Cheng, Hongbing; Lu, Shuai

    2013-04-01

    For investigating the static tensile and dynamic fatigue behaviors of bulk materials, a miniaturized device with separate modular tensile and fatigue actuators was developed. The fatigue actuator presented good compatibility with the tensile actuator and mainly consisted of a special flexure hinge and piezoelectric stack. In situ fatigue tests under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. A displacement correction method of tensile actuator based on load sensor compliance was investigated, and the feasibility of the method was verified by the comparison tests with a commercial tensile instrument. The application of testing the storage and loss modulus as a function of frequency was explained, and the temperature rises of both the piezoelectric stack and specimen were obtained as a function of frequency. Output characteristics of the fatigue actuator were also investigated. Additionally, the discharge performance of piezoelectric stack based on various initial voltages and fatigue tests on C11000 copper was carried out. This paper shows a modularized example that combines a servo motor with a piezoelectric actuator attached to the specimen grip to realize the in situ fatigue tests.

  17. Novel in situ device for investigating the tensile and fatigue behaviors of bulk materials

    NASA Astrophysics Data System (ADS)

    Ma, Zhichao; Zhao, Hongwei; Li, Qinchao; Wang, Kaiting; Zhou, Xiaoqin; Hu, Xiaoli; Cheng, Hongbing; Lu, Shuai

    2013-04-01

    For investigating the static tensile and dynamic fatigue behaviors of bulk materials, a miniaturized device with separate modular tensile and fatigue actuators was developed. The fatigue actuator presented good compatibility with the tensile actuator and mainly consisted of a special flexure hinge and piezoelectric stack. In situ fatigue tests under scanning electron microscope or metallographic microscope could be carried out due to the miniaturized dimensions of the device. A displacement correction method of tensile actuator based on load sensor compliance was investigated, and the feasibility of the method was verified by the comparison tests with a commercial tensile instrument. The application of testing the storage and loss modulus as a function of frequency was explained, and the temperature rises of both the piezoelectric stack and specimen were obtained as a function of frequency. Output characteristics of the fatigue actuator were also investigated. Additionally, the discharge performance of piezoelectric stack based on various initial voltages and fatigue tests on C11000 copper was carried out. This paper shows a modularized example that combines a servo motor with a piezoelectric actuator attached to the specimen grip to realize the in situ fatigue tests.

  18. Physical characteristics affecting the tensile failure properties of compact bone.

    PubMed

    Currey, J D

    1990-01-01

    Compact bone specimens from a wide variety of reptiles, birds, and mammals were tested in tension, and their failure properties related to mineral volume fraction, porosity and histological orientation. The principal findings were that the ultimate strain and the work under the stress-strain curve declined sharply with mineralisation, as did the stress and strain appearing after the specimen had yielded. Ultimate tensile strength was not simply related to any combination of the possible explanatory variables, but some relatively poorly mineralised bones, notably antlers, had high stresses at failure. These high strengths were allowed by a great increase in stress after the bones had yielded at quite low stresses.

  19. 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.

  20. 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