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Sample records for charpy impact tests

  1. Quality assurance of absorbed energy in Charpy impact test

    NASA Astrophysics Data System (ADS)

    Rocha, C. L. F.; Fabricio, D. A. K.; Costa, V. M.; Reguly, A.

    2016-07-01

    In order to ensure the quality assurance and comply with standard requirements, an intralaboratory study has been performed for impact Charpy tests, involving two operators. The results based on ANOVA (Analysis of Variance) and Normalized Error statistical techniques pointed out that the execution of the tests is appropriate, because the implementation of quality assurance methods showed acceptable results.

  2. Microstructural characterization of Charpy-impact-tested nanostructured bainite

    SciTech Connect

    Tsai, Y.T.; Chang, H.T.; Huang, B.M.; Huang, C.Y.; Yang, J.R.

    2015-09-15

    In this work, a possible cause of the extraordinary low impact toughness of nanostructured bainite has been investigated. The microstructure of nanostructured bainite consisted chiefly of carbide-free bainitic ferrite with retained austenite films. X-ray diffractometry (XRD) measurement indicated that no retained austenite existed in the fractured surface of the Charpy-impact-tested specimens. Fractographs showed that cracks propagated mainly along bainitic ferrite platelet boundaries. The change in microstructure after impact loading was verified by transmission electron microscopy (TEM) observations, confirming that retained austenite was completely transformed to strain-induced martensite during the Charpy impact test. However, the zone affected by strained-induced martensite was found to be extremely shallow, only to a depth of several micrometers from the fracture surface. It is appropriately concluded that upon impact, as the crack forms and propagates, strain-induced martensitic transformation immediately occurs ahead of the advancing crack tip. The successive martensitic transformation profoundly facilitates the crack propagation, resulting in the extremely low impact toughness of nanostructured bainite. Retained austenite, in contrast to its well-known beneficial role, has a deteriorating effect on toughness during the course of Charpy impact. - Highlights: • The microstructure of nanostructured bainite consisted of nano-sized bainitic ferrite subunits with retained austenite films. • Special sample preparations for SEM, XRD and TEM were made, and the strain-affected structures have been explored. • Retained austenite films were found to transform into martensite after impact loading, as evidenced by XRD and TEM results. • The zone of strain-induced martensite was found to extend to only several micrometers from the fracture surface. • The poor Charpy impact toughness is associated with the fracture of martensite at a high strain rate during

  3. Charpy impact test results for low-activation ferritic alloys

    SciTech Connect

    Cannon, N.S.; Hu, W.L.; Gelles, D.S.

    1987-05-01

    The objective of this work is to evaluate the shift of the ductile to brittle transition temperature (DBTT) and the reduction of the upper shelf energy (USE) due to neutron irradiation of low activation ferritic alloys. Six low activation ferritic alloys have been tested following irradiation at 365/sup 0/C to 10 dpa and compared with control specimens in order to assess the effect of irradiation on Charpy impact properties.

  4. Current status of small specimen technology in Charpy impact testing

    NASA Astrophysics Data System (ADS)

    Kurishita, H.; Kayano, H.; Narui, M.; Yamazaki, M.

    1994-09-01

    The current status of small-scale specimen technology in Charpy impact testing for ferritic steels is presented, with emphasis on the effect of the notch dimensions (notch depth, notch root radius and notch angle) on the upper shelf energy (USE) and ductile-to-brittle transition temperature (DBTT). The USE for miniaturized specimens, normalized by Bb2 or ( Bb{3}/{2} ( B is the specimen thickness, b the ligament size), is essentially independent of notch geometry and has a linear relationship with the USE of full size specimens, regardless of irradiation and alloy conditions. The DBTT of miniaturized specimens depends strongly on the notch dimensions; this dependence of the DBTT decreases as the DBTT of full size specimens increase due to neutron irradiation or thermal aging. These results may be useful in determining the USE and DBTT for full size specimens from those for miniaturized specimens.

  5. Fracture Behavior and Delamination Toughening of Molybdenum in Charpy Impact Tests

    NASA Astrophysics Data System (ADS)

    Babinsky, K.; Primig, S.; Knabl, W.; Lorich, A.; Stickler, R.; Clemens, H.

    2016-11-01

    This study combines advanced characterization techniques with conventional Charpy impact tests to relate the mechanical properties to the microstructure of technically pure molybdenum, especially regarding its toughness. V-notched samples with different orientations were prepared from a rolled molybdenum plate in stress-relieved and recrystallized condition. The ductile-to-brittle transition-temperature was analyzed in terms of the delamination behavior influenced by the microstructure. A pronounced increase of toughness was found for specific oriented samples, which can be explained by macroscopic delamination. Elongated grains led to enhanced delamination in Charpy impact tests with variations for different orientations. In general, delamination occurs as a result of brittle fracture; however, an increase in toughness in the Charpy impact test can be provoked. This mechanism is called thin sheet toughening or delamination toughening. Electron backscatter diffraction measurements were performed to get a deeper knowledge about crack propagation and delamination behavior in the rolled plate. Recrystallization shifts the transition region to significantly higher temperatures, which is explained by the globular grain shape as well as grain boundary segregation. The occurrence of delamination is discussed, taking texture, grain shape and segregation effects into account.

  6. Specimen size effects on ductile?brittle transition temperature in Charpy impact testing

    NASA Astrophysics Data System (ADS)

    Kurishita, H.; Yamamoto, T.; Narui, M.; Suwarno, H.; Yoshitake, T.; Yano, Y.; Yamazaki, M.; Matsui, H.

    2004-08-01

    One key issue for small specimen test techniques is to clarify specimen size effects on test results. In consideration of size effects on determining the ductile-to-brittle transition temperature (DBTT) in Charpy impact testing, a method to evaluate the plastic constraint loss for differently sized Charpy V-notch (CVN) specimens is proposed and applied to a ferritic-martensitic steel, 2WFK, developed by JNC. In the method, a constraint factor, α, that is an index of the plastic constraint is defined as α=σ ∗/σ y∗. Here, σ ∗ is the critical cleavage fracture stress which is a material constant and σ y∗ is the uniaxial yield stress at the DBTT at the strain rate generated in the Charpy impact test. The procedures for evaluating each of σ ∗ and σ y∗ are described and a result of σ ∗ and σ y∗, thus the value of α, is presented for different types of miniaturized and full-sized CVN specimens of 2WFK.

  7. Charpy impact tests on martensitic/ferritic steels after irradiation in SINQ target-3

    NASA Astrophysics Data System (ADS)

    Dai, Yong; Marmy, Pierre

    2005-08-01

    Charpy impact tests were performed on martensitic/ferritic (MF) steels T91, F82H, Optifer-V and Optimax-A/-C irradiated in SINQ Target-3 up to 7.5 dpa and 500 appm He in a temperature range of 120-195 °C. Results demonstrate that for all the four kinds of steels, the ductile-to-brittle transition temperature (DBTT) increases with irradiation dose. The difference in the DBTT shifts (ΔDBTT) of the different steels is not significant after irradiation in the SINQ target. The ΔDBTT data from the previous small punch (Δ DBTT SP) and the present Charpy impact (ΔDBTT CVN) tests can be correlated with the expression: Δ DBTT SP = 0.4ΔDBTT CVN. All the ΔDBTT data fall into a linear band when they are plotted versus helium concentration. The results indicate that helium effects on the embrittlement of MF steels are significant, particularly at higher concentrations. It suggests that MF steels may not be very suitable for applications at low temperatures in spallation irradiation environments where helium production is high.

  8. On the (in)adequacy of the Charpy impact test to monitor irradiation effects of ferritic/martensitic steels

    NASA Astrophysics Data System (ADS)

    Chaouadi, R.

    2007-02-01

    Irradiation embrittlement studies rely very often on Charpy impact data, in particular the ductile-to-brittle transition temperature (DBTT). However, while the DBTT-shift is equivalent to the increase of the fracture toughness transition temperature of ferritic steels, it is not the case for ferritic/martensitic steels. The aim of this study is to critically assess experimental data obtained on a 9%Cr-ferritic/martensitic steel, Eurofer-97, to better understand the underlying mechanisms involved during the fracture process. More specifically, a dedicated analysis using the load diagram approach allows to unambiguously reveal the actual effects of irradiation on physically rather than empirically based parameters. A comparison is made between a ferritic and ferritic/martensitic steel to better identify the possible similarities and differences. Tensile, Charpy impact and fracture toughness tests data are examined in a global approach to assess the actual rather than apparent irradiation effects. The adequacy or inadequacy of the Charpy impact test to monitor irradiation effects is extensively discussed.

  9. On impact testing of subsize Charpy V-notch type specimens

    SciTech Connect

    Mikhail, A.S.; Nanstad, R.K.

    1994-12-31

    The potential for using subsize specimens to determine the actual properties of reactor pressure vessel steels is receiving increasing attention for improved vessel condition monitoring that could be beneficial for light-water reactor plant-life extension. This potential is made conditional upon, on the one hand, by the possibility of cutting samples of small volume from the internal surface of the pressure vessel for determination of actual properties of the operating pressure vessel. The plant-life extension will require supplemental surveillance data that cannot be provided by the existing surveillance programs. Testing of subsize specimens manufactured from broken halves of previously tested surveillance Charpy V-notch (CVN) specimens offers an attractive means of extending existing surveillance programs. Using subsize CVN type specimens requires the establishment of a specimen geometry that is adequate to obtain a ductile-to-brittle transition curve similar to that obtained from full-size specimens. This requires the development of a correlation of transition temperature and upper-shelf toughness between subsize and full-size specimens. The present study was conducted under the Heavy-Section Steel Irradiation Program. Different published approaches to the use of subsize specimens were analyzed and five different geometries of subsize specimens were selected for testing and evaluation. The specimens were made from several types of pressure vessel steels with a wide range of yield strengths, transition temperatures, and upper-shelf energies (USEs). Effects of specimen dimensions, including depth, angle, and radius of notch have been studied. The correlation of transition temperature determined from different types of subsize specimens and the full-size specimen is presented. A new procedure for transforming data from subsize specimens was developed and is presented.

  10. Correlation between standard Charpy and sub-size Charpy test results of selected steels in upper shelf region

    NASA Astrophysics Data System (ADS)

    Konopík, P.; Džugan, J.; Bucki, T.; Rzepa, S.; Rund, M.; Procházka, R.

    2017-02-01

    Absorbed energy obtained from impact Charpy tests is one of the most important values in many applications, for example in residual lifetime assessment of components in service. Minimal absorbed energy is often the value crucial for extending components service life, e.g. turbines, boilers and steam lines. Using a portable electric discharge sampling equipment (EDSE), it is possible to sample experimental material non-destructively and subsequently produce mini-Charpy specimens. This paper presents a new approach in correlation from sub-size to standard Charpy test results.

  11. Charpy impact test results for low activation ferritic alloys irradiated to 30 dpa

    SciTech Connect

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S.

    1996-04-01

    Miniature specimens of six low activation ferritic alloys have been impact field tested following irradiation at 370{degrees}C to 30 dpa. Comparison of the results with those of control specimens and specimens irradiated to 10 dpa indicates that degradation in the impact behavior appears to have saturated by {approx}10 dpa in at least four of these alloys. The 7.5Cr-2W alloy referred to as GA3X appears most promising for further consideration as a candidate structural material in fusion reactor applications, although the 9Cr-1V alloy may also warrant further investigation.

  12. Low blow Charpy impact of silicon carbides

    NASA Technical Reports Server (NTRS)

    Abe, H.; Chandan, H. C.; Bradt, R. C.

    1978-01-01

    The room-temperature impact resistance of several commercial silicon carbides was examined using an instrumented pendulum-type machine and Charpy-type specimens. Energy balance compliance methods and fracture toughness approaches, both applicable to other ceramics, were used for analysis. The results illustrate the importance of separating the machine and the specimen energy contributions and confirm the equivalence of KIc and KId. The material's impact energy was simply the specimen's stored elastic strain energy at fracture.

  13. Effect of Local Crystallographic Texture on the Fissure Formation During Charpy Impact Testing of Low-Carbon Steel

    NASA Astrophysics Data System (ADS)

    Ghosh, Abhijit; Patra, Sudipta; Chatterjee, Arya; Chakrabarti, Debalay

    2016-06-01

    The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║<001>] and gamma [ND║<111>] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the `effective grain size,' which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the `main fracture plane' and `fissure plane.' Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse `fissure plane,' by increasing the `effective grain size' and decreasing the cleavage fracture stress on that plane.

  14. Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm K.

    2012-01-01

    60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

  15. Charpy impact test results of four low activation ferritic alloys irradiated at 370{degrees}C to 15 DPA

    SciTech Connect

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S.

    1996-10-01

    Miniature CVN specimens of four low activation ferritic alloys have been impact tested following irradiation at 370{degrees}C to 15 dpa. Comparison of the results with those of control specimens indicates that degradation in the impact behavior occurs in each of these four alloys. The 9Cr-2W alloy referred to as GA3X and the similar alloy F82H with 7.8Cr-2W appear most promising for further consideration as candidate structural materials in fusion energy system applications. These two alloys exhibit a small DBTT shift to higher temperatures but show increased absorbed energy on the upper shelf.

  16. Further Charpy impact test results of low activation ferritic alloys, irradiated at 430{degrees}C to 67 dpa

    SciTech Connect

    Schubert, L.E.; Hamilton, M.L.; Gelles, D.S.

    1997-04-01

    Miniature CVN specimens of four ferritic alloys, GA3X, F82H, GA4X and HT9, have been impact tested following irradiation at 430{degrees}C to 67 dpa. Comparison of the results with those of the previously tested lower dose irradiation condition indicates that the GA3X and F82H alloys, two primary candidate low activation alloys, exhibit virtually identical behavior following irradiation at 430{degrees}C to {approximately}67 dpa and at 370{degrees}C to {approximately}15 dpa. Very little shift is observed in either DBTT or USE relative to the unirradiated condition. The shifts in DBTT and USE observed in both GA4X and HT9 were smaller after irradiation at 430{degrees}C to {approximately}67 dpa than after irradiation at 370{degrees}C to {approximately}15 dpa.

  17. Tensile and Charpy impact properties of irradiated reduced-activation ferritic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1996-10-01

    Tensile tests were conducted on 8 reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on steels irradiated to 26-29 dpa. Irradiation was in Fast Flux Test Facility at 365 C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15- 17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20,000 h at 365 C. Thermal aging had little effect on tensile properties or ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in upper-shelf energy (USE). After 7 dpa, strength increased (hardened) and then remained relatively unchanged through 26-29 dpa (ie, strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness (increased DBTT, decreased USE) remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels had the most irradiation resistance.

  18. Tensile and charpy impact properties of irradiated reduced-activation ferritic steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1996-10-01

    Tensile tests were conducted on eight reduced-activation Cr-W steels after irradiation to 15-17 and 26-29 dpa, and Charpy impact tests were conducted on the steels irradiated to 26-29 dpa. Irradiation was in the Fast Flux Test Facility at 365{degrees}C on steels containing 2.25-12% Cr, varying amounts of W, V, and Ta, and 0.1%C. Previously, tensile specimens were irradiated to 6-8 dpa and Charpy specimens to 6-8, 15-17, and 20-24 dpa. Tensile and Charpy specimens were also thermally aged to 20000 h at 365{degrees}C. Thermal aging had little effect on the tensile behavior or the ductile-brittle transition temperature (DBTT), but several steels showed a slight increase in the upper-shelf energy (USE). After {approx}7 dpa, the strength of the steels increased and then remained relatively unchanged through 26-29 dpa (i.e., the strength saturated with fluence). Post-irradiation Charpy impact tests after 26-29 dpa showed that the loss of impact toughness, as measured by an increase in DBTT and a decrease in the USE, remained relatively unchanged from the values after 20-24 dpa, which had been relatively unchanged from the earlier irradiations. As before, the two 9Cr steels were the most irradiation resistant.

  19. Miniaturized Charpy test for reactor pressure vessel embrittlement characterization

    SciTech Connect

    Manahan, M.P. Sr.

    1999-10-01

    Modifications were made to a conventional Charpy machine to accommodate the miniaturized Charpy V-Notch (MCVN) specimens which were fabricated from an archived reactor pressure vessel (RPV) steel. Over 100 dynamic MCVN tests were performed and compared to the results from conventional Charpy V-Notch (CVN) tests to demonstrate the efficacy of the miniature specimen test. The optimized sidegrooved MCVN specimens exhibit transitional fracture behavior over essentially the same temperature range as the CVN specimens which indicates that the stress fields in the MCVN specimens reasonably simulate those of the CVN specimens and this fact has been observed in finite element calculations. This result demonstrates a significant breakthrough since it is now possible to measure the ductile-brittle transition temperature (DBTT) using miniature specimens with only small correction factors, and for some materials as in the present study, without the need for any correction factor at all. This development simplifies data interpretation and will facilitate future regulatory acceptance. The non-sidegrooved specimens yield energy-temperature data which is significantly shifted downward in temperature (non-conservative) as a result of the loss of constraint which accompanies size reduction.

  20. Effect of grain structure on Charpy impact behavior of copper

    NASA Astrophysics Data System (ADS)

    Liang, Ningning; Zhao, Yonghao; Wang, Jingtao; Zhu, Yuntian

    2017-03-01

    Nanostructured (NS) and ultrafine-grained (UFG) materials have high strength and relatively low ductility. Their toughness has not been comprehensively investigated. Here we report the Charpy impact behavior and the corresponding microstructural evolutions in UFG Cu with equi-axed and elongated grains which were prepared by equal channel angular pressing (ECAP) for 2 and 16 passes at room temperature. It is found that their impact toughness (48 J/cm2) is almost comparable to that of coarse grained (CG) Cu: 55 J/cm2. The high strain rate during the Charpy impact was found to enhance the strain hardening capability of the UFG Cu due to the suppression of dynamic dislocation recovery. The crack in the CG Cu was blunted by dislocation-slip mediated plastic deformation, while the cracks in the UFG Cu were formed at grain boundaries and triple junctions due to their limited plasticity. Near the crack surfaces the elongated grains in ECAP-2 sample were refined by recrystallization, while equi-axed grains in the ECAP-16 sample grew larger.

  1. Effect of grain structure on Charpy impact behavior of copper

    PubMed Central

    Liang, Ningning; Zhao, Yonghao; Wang, Jingtao; Zhu, Yuntian

    2017-01-01

    Nanostructured (NS) and ultrafine-grained (UFG) materials have high strength and relatively low ductility. Their toughness has not been comprehensively investigated. Here we report the Charpy impact behavior and the corresponding microstructural evolutions in UFG Cu with equi-axed and elongated grains which were prepared by equal channel angular pressing (ECAP) for 2 and 16 passes at room temperature. It is found that their impact toughness (48 J/cm2) is almost comparable to that of coarse grained (CG) Cu: 55 J/cm2. The high strain rate during the Charpy impact was found to enhance the strain hardening capability of the UFG Cu due to the suppression of dynamic dislocation recovery. The crack in the CG Cu was blunted by dislocation-slip mediated plastic deformation, while the cracks in the UFG Cu were formed at grain boundaries and triple junctions due to their limited plasticity. Near the crack surfaces the elongated grains in ECAP-2 sample were refined by recrystallization, while equi-axed grains in the ECAP-16 sample grew larger. PMID:28303950

  2. Effect of grain structure on Charpy impact behavior of copper.

    PubMed

    Liang, Ningning; Zhao, Yonghao; Wang, Jingtao; Zhu, Yuntian

    2017-03-17

    Nanostructured (NS) and ultrafine-grained (UFG) materials have high strength and relatively low ductility. Their toughness has not been comprehensively investigated. Here we report the Charpy impact behavior and the corresponding microstructural evolutions in UFG Cu with equi-axed and elongated grains which were prepared by equal channel angular pressing (ECAP) for 2 and 16 passes at room temperature. It is found that their impact toughness (48 J/cm(2)) is almost comparable to that of coarse grained (CG) Cu: 55 J/cm(2). The high strain rate during the Charpy impact was found to enhance the strain hardening capability of the UFG Cu due to the suppression of dynamic dislocation recovery. The crack in the CG Cu was blunted by dislocation-slip mediated plastic deformation, while the cracks in the UFG Cu were formed at grain boundaries and triple junctions due to their limited plasticity. Near the crack surfaces the elongated grains in ECAP-2 sample were refined by recrystallization, while equi-axed grains in the ECAP-16 sample grew larger.

  3. Influence of Stacking Sequence and Notch Angle on the Charpy Impact Behavior of Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Behnia, S.; Daghigh, V.; Nikbin, K.; Fereidoon, A.; Ghorbani, J.

    2016-09-01

    The low-velocity impact behavior of hybrid composite laminates was investigated. The epoxy matrix was reinforced with aramid, glass, basalt, and carbon fabrics using the hand lay-up technique. Different stacking sequences and notch angles were and notch angles considered and tested using a Charpy impact testing machine to study the hybridization and notch angle effects on the impact response of the hybrid composites. The energy absorption capability of specimens with different stacking sequences and notch angles is compared and discussed. It is shown that the hybridization can enhance the mechanical performance of composite materials.

  4. Validation Study of Unnotched Charpy and Taylor-Anvil Impact Experiments using Kayenta

    SciTech Connect

    Kamojjala, Krishna; Lacy, Jeffrey; Chu, Henry S.; Brannon, Rebecca

    2015-03-01

    Validation of a single computational model with multiple available strain-to-failure fracture theories is presented through experimental tests and numerical simulations of the standardized unnotched Charpy and Taylor-anvil impact tests, both run using the same material model (Kayenta). Unnotched Charpy tests are performed on rolled homogeneous armor steel. The fracture patterns using Kayenta’s various failure options that include aleatory uncertainty and scale effects are compared against the experiments. Other quantities of interest include the average value of the absorbed energy and bend angle of the specimen. Taylor-anvil impact tests are performed on Ti6Al4V titanium alloy. The impact speeds of the specimen are 321 m/s and 393 m/s. The goal of the numerical work is to reproduce the damage patterns observed in the laboratory. For the numerical study, the Johnson-Cook failure model is used as the ductile fracture criterion, and aleatory uncertainty is applied to rate-dependence parameters to explore its effect on the fracture patterns.

  5. Charpy impact toughness of martensitic steels irradiated in FFTF: Effect of heat treatment

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1992-12-31

    Charpy tests were made on plates of 9Cr-1MoVNb and 12Cr-1MoVW steels given four different normalizing-and-tempering treatments. One-third-size Charpy specimens from each steel were irradiated to 7.4-8 {times} 10{sup 26} n/m{sup 2} (about 34--37 dpa) at 420C in the Materials Open Test Assembly of the Fast Flux Test Facility. Specimens were also thermally aged to 20000 h at 400C to determine the effect of aging during irradiation. Previous work on these steels irradiated to 4--5 dpa at 365C in MOTA were reexamined in light of the new results. The tests indicated that prior austenite grain size, which was varied by different normalizing treatments, had an effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. conclusions are presented on how heat treatment can be used to optimize properties.

  6. Charpy impact toughness of martensitic steels irradiated in FFTF: Effect of heat treatment

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1992-01-01

    Charpy tests were made on plates of 9Cr-1MoVNb and 12Cr-1MoVW steels given four different normalizing-and-tempering treatments. One-third-size Charpy specimens from each steel were irradiated to 7.4-8 [times] 10[sup 26] n/m[sup 2] (about 34--37 dpa) at 420C in the Materials Open Test Assembly of the Fast Flux Test Facility. Specimens were also thermally aged to 20000 h at 400C to determine the effect of aging during irradiation. Previous work on these steels irradiated to 4--5 dpa at 365C in MOTA were reexamined in light of the new results. The tests indicated that prior austenite grain size, which was varied by different normalizing treatments, had an effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. conclusions are presented on how heat treatment can be used to optimize properties.

  7. Results of Charpy V-Notch Impact Testing of Structural Steel Specimens Irradiated at ~30°C to 1 x 1016 neutrons/cm2 in a Commercial Reactor Cavity

    SciTech Connect

    Iskander, S. K.; Stoller, R. E.

    1997-04-01

    A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at ~30°C (~ 85°F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 1016 neutrons/cm2 (>1 MeV). The capsule included six CVN impact specimens of archival High Flux Isotope Reactor A212 grade B ferritic steel and five CVN impact specimens of a well-studied A36 structural steel. This irradiation was part of the ongoing study of neutron-induced damage effects at the low temperature and flux experienced by reactor supports. The plant operators shut down the plant before the planned exposure was reached. The exposure of these specimens produced no significant irradiation-induced embrittlement. Of interest were the data on unirradiated specimens in the L-T orientation machined from a single plate of A36 structural steel, which is the same specification for the structural steel used in some reactor supports. The average CVN energy of five unirradiated specimens obtained from one region of the plate and tested at room temperature was ~ 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of ~ 220%. The CVN impact energies for all 18 specimens ranged from a low of 32 J to a high of 111 J. Moreover, it appears that the University of Kansas CVN impact energy data of the unirradiated specimens at the 100-J level are shifted toward higher temperatures by about 20 K. The results were an example of the extent of scatter possible in CVN impact testing. Generic values for the CVN impact energy of A36 should be used with caution in critical applications.

  8. Effects of carbide precipitation on the strength and Charpy impact properties of low carbon Mn-Ni-Mo bainitic steels

    NASA Astrophysics Data System (ADS)

    Im, Young-Roc; Jun Oh, Yong; Lee, Byeong-Joo; Hwa Hong, Jun; Lee, Hu-Chul

    2001-08-01

    The effects of carbide precipitation on the strength and Charpy impact properties of tempered bainitic Mn-Ni-Mo steels have been investigated. An attempt has also been made to modify the microstructure of the steels in order to improve the Charpy properties, by controlling the alloy composition being guided by thermodynamic calculations of phase equilibria. Coarse rod type or agglomerated spherical type cementite particles in inter-lath region were considered to be mostly detrimental to Charpy impact properties. By reducing the precipitation of cementite through decreasing carbon content and/or by substituting it into fine M 2C carbides through increasing the molybdenum content, DBTT could be lowered significantly. Further decrease of DBTT could be achieved by substituting part of manganese content by nickel. Yield strength of tested alloys could be maintained at the level of a reference 0.2 wt% carbon alloy in spite of the significant reduction in carbon content, mainly by the increase in the precipitation of fine M 2C type carbides with increased molybdenum content.

  9. A Method to Estimate the Optimum Temperature for the Cryo-Shattering Separation Using a Charpy Impact Tester

    NASA Astrophysics Data System (ADS)

    Hagura, Yoshio; Watanabe, Hisahiko

    A cryo-shattering separation is a recently developed separation method which is applied to collect low-fat meat from fatty fish. This separation method needs to be operated at the optimum temperature for the cryo-shattering. Determining on optimum temperature needs much works and costs. In this study,an easy method to estimate the optimum temperature for cryo-shattering was proposed using a Charpy impact tester. Four kinds of characteristic temperatures observed through impact tests were used to construct a fracture-temperature-map. By use of the map,the optimum temperature for cryo-shattering was obtained without shattering/sieving experiments.

  10. An automated digital data collection and analysis system for the Charpy Impact Tester

    NASA Technical Reports Server (NTRS)

    Kohne, Glenn S.; Spiegel, F. Xavier

    1994-01-01

    The standard Charpy Impact Tester has been modified by the addition of a system of hardware and software to improve the accuracy and consistency of measurements made during specimen fracturing experiments. An optical disc, light source, and detector generate signals that indicate the pendulum position as a function of time. These signals are used by a computer to calculate the velocity and kinetic energy of the pendulum as a function of its position.

  11. A reassessment of the effects of helium on Charpy impact properties of ferritic/martensitic steels

    SciTech Connect

    Gelles, D.S.; Hamilton, M.L.; Hankin, G.L.

    1998-03-01

    To test the effect of helium on Charpy impact properties of ferritic/martensitic steels, two approaches are reviewed: quantification of results of tests performed on specimens irradiated in reactors with very different neutron spectra, and isotopic tailoring experiments. Data analysis can show that if the differences in reactor response are indeed due to helium effects, then irradiation in a fusion machine at 400 C to 100 dpa and 1000 appm He will result in a ductile to brittle transition temperature shift of over 500 C. However, the response as a function of dose and helium level is unlikely to be simply due to helium based on physical reasoning. Shear punch tests and microstructural examinations also support this conclusion based on irradiated samples of a series of alloys made by adding various isotopes of nickel in order to vary the production of helium during irradiation in HFIR. The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys. However, helium itself, up to 75 appm at over 7 dpa appears to have little effect on the mechanical properties of the alloys. This behavior is instead understood to result from complex precipitation response. The database for effects of helium on embrittlement based on nickel additions is therefore probably misleading and experiments should be redesigned to avoid nickel precipitation.

  12. Charpy impact toughness of martensitic steels irradiated in FFTF: Effect of heat treatment

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1992-12-31

    Plates of 9Cr-1MoVNb and 12Cr-1 MoVW steels were normalized and then tempered at two different tempering conditions. One-third-size Charpy specimens from each steel were irradiated to 7.4-8{times}10{sup 26} n/m{sup 2} (about {approximately}35 dpa) at 420{degrees}C in the Materials Open Test Assembly (MOTA) of the Fast Flux Test Facility. Specimens were also thermally aged to 20,000 h at 400{degrees}C to compare the effect of aging and irradiation. Previous work on the steels irradiated to 4-5 dpa at 365{degrees}C in MOTA were reexamined in light of the new results. The tests indicated that prior-austenite grain size, which was varied by different normalizing treatments, had an effect on impact behavior of the 9Cr-1MoVNb but not on the 12Cr-1MoVW. Tempering treatment had relatively little effect on the shift in DBTT for both steels. Conclusions are presented on how heat treatment can be used to optimize properties.

  13. A review of some effects of helium on charpy impact properties of ferritic/martensitic steels

    NASA Astrophysics Data System (ADS)

    Gelles, D. S.; Hankin, G. L.; Hamilton, M. L.

    1998-10-01

    To evaluate the effect of helium on Charpy impact properties of ferritic/martensitic steels, two approaches are reviewed: quantification of results of earlier tests performed by other researchers on specimens irradiated in reactors with very different neutron spectra, and evaluation of isotopic tailoring experiments. Data analysis can show that if the differences in reactor response are indeed due to helium effects, then irradiation in a fusion machine at 400°C to 100 dpa and 1000 appm He will result in a ductile-to-brittle transition temperature (DBTT) shift of over 500°C. However, it can be shown that the response as a function of dose and helium level is unlikely to be simply due to helium based on physical reasoning. Shear punch tests and microstructural examinations support this conclusion based on irradiated samples of a series of alloys made by adding various isotopes of nickel in order to vary the production of helium during irradiation in High Flux Isotope Reactor (HFIR). The addition of nickel at any isotopic balance to the Fe-12Cr base alloy significantly increased the shear yield and maximum strengths of the alloys. However, helium itself, up to 75 appm at over 7 dpa appears to have little effect on the mechanical properties of the alloys. This behavior is instead understood to result from complex precipitation response. The database for effects of helium on embrittlement based on nickel additions is therefore probably misleading and experiments should be redesigned to avoid nickel precipitation.

  14. PALS combined with Charpy-V tests at WWER reactor pressure vessel steels

    NASA Astrophysics Data System (ADS)

    Slugeň, V.; Kryukov, A.; Petriska, M.; Veterníková, J.; Sojak, S.; Sabelová, V.; Hinca, R.

    2013-06-01

    This paper presents results from our long-term studies of irradiated, commercially used WWER reactor pressure vessel steels. Results from Charpy-V tests and positron annihilation spectroscopy techniques are compared and discussed in details, having in mind actual state of art and other microstructural studies in this area. The optimal region for annealing of irradiation induced defects was analyzed. It was shown that WWER steel with low impurity contents has good radiation stability and operation these reactor pressure vessels could be extended beyond a design lifetime.

  15. Effect of Cadmium Plating Thickness on the Charpy Impact Energy of Hydrogen-Charged 4340 Steel

    NASA Astrophysics Data System (ADS)

    Es-Said, O. S.; Alcisto, J.; Guerra, J.; Jones, E.; Dominguez, A.; Hahn, M.; Ula, N.; Zeng, L.; Ramsey, B.; Mulazimoglu, H.; Li, Yong-Jun; Miller, M.; Alrashid, J.; Papakyriakou, M.; Kalnaus, S.; Lee, E. W.; Frazier, W. E.

    2016-09-01

    Hydrogen was intentionally introduced into ultra-high strength steel by cadmium plating. The purpose was to examine the effect of cadmium plate thickness and hence hydrogen on the impact energy of the steel. The AISI 4340 steel was austenitized at 1000 °C for 1 h, water quenched, and tempered at temperatures between 257 and 593 °C in order to achieve a range of targeted strength levels. The specimens were cadmium plated with 0.00508 mm (0.2 mils), 0.00762 mm (0.3 mils), and 0.0127 mm (0.5 mils). Results demonstrated that the uncharged specimens exhibited higher impact energy values when compared to the plated specimens at all tempering temperatures. The cadmium-plated specimens had very low Charpy impact values irrespective of their ultimate tensile strength values. The model of hydrogen transport by mobile dislocations to the fracture site appears to provide the most suitable explanation of the results.

  16. An overview of the principles of modeling Charpy impact energy data using statistical analysis

    SciTech Connect

    Moskovic, R.; Flewitt, P.E.J.

    1997-12-01

    Integrity assessments of Magnox nuclear reactors with steel pressure vessels quantify the temperature margins between the operating temperature of the plant, at any given location, and the onset of upper-shelf temperature. The onset of upper-shelf temperature can be estimated from the fracture toughness properties of each material used in the construction of the pressure vessels. Although start-of-life fracture toughness properties of the materials have been measured, such properties are not available for the neutron-irradiated and thermally aged condition. One of the main effects of neutron irradiation and temperature experienced during service is to increase the ductile-to-brittle transition temperature (DBTT), which can be represented in terms of temperature shifts. In the irradiation surveillance schemes for the Magnox reactors, these temperature shifts can be inferred from Charpy impact energy data which have been measured regularly during the service life. Since Charpy impact energy data are inherently scattered, it is necessary to optimize the interpretation of the data by statistical processing. A recent analysis undertaken by Moskovic et al. concluded that Bayesian analyses are best suited to address the problem. In this overview, the authors consider the requirements of such analyses and the various options available. They then consider the method proposed by Moskovic et al. with respect to the requirements of the inputs to the integrity assessment and the validity of this approach. In this method of analysis, the distribution of all possible values of model coefficients is established by judging the various possible combinations of these model coefficients in relation to the likelihood of the observed data. Analysis of artificially generated data has been used to compare the effectiveness of Bayesian analyses with those used traditionally.

  17. An improved correlation procedure for subsize and full-size Charpy impact specimen data

    SciTech Connect

    Sokolov, M.A.; Alexander, D.J.

    1997-03-01

    The possibility of using subsize specimens to monitor the properties of reactor pressure vessel steels is receiving increasing attention for light-water reactor plant life extension. This potential results from the possibility of cutting samples of small volume form the internal surface of the pressure vessel for determination of the actual properties of the operating pressure vessel. In addition, plant life extension will require supplemental data that cannot be provided by existing surveillance programs. Testing of subsize specimens manufactured from broken halves of previously tested surveillance Charpy specimens offers an attractive means of extending existing surveillance programs. Using subsize Charpy V-notch-type specimens requires the establishment of a specimen geometry that is adequate to obtain a ductile-to-brittle transition curve similar to that obtained from full-size specimens, and the development of correlations for transition temperature and upper-shelf energy (USE) level between subsize and full-size specimens. Five different geometries of subsize specimens were selected for testing and evaluation. The specimens were made from several types of pressure vessel steels with a wide range of yield strengths, transition temperatures, and USEs. The effects of specimen dimensions, including notch depth, angle, and radius, have been studied. The correlations of transition temperatures determined from different types of subsize specimens and the full-size specimens are presented. A new procedure for transforming data from subsize specimens is developed. The transformed data are in good agreement with data from full-size specimens for materials that have USE levels less than 200 J.

  18. Impact Tests for Woods

    NASA Technical Reports Server (NTRS)

    1922-01-01

    Although it is well known that the strength of wood depends greatly upon the time the wood is under the load, little consideration has been given to this fact in testing materials for airplanes. Here, results are given of impact tests on clear, straight grained spruce. Transverse tests were conducted for comparison. Both Izod and Charpy impact tests were conducted. Results are given primarily in tabular and graphical form.

  19. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels.

    PubMed

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-02-02

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400-450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0-1.2 GPa at room temperature, which is nearly 3-5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry.

  20. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels

    PubMed Central

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-01-01

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400–450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0–1.2 GPa at room temperature, which is nearly 3–5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry. PMID:28150692

  1. Ultrahigh Charpy impact toughness (~450J) achieved in high strength ferrite/martensite laminated steels

    NASA Astrophysics Data System (ADS)

    Cao, Wenquan; Zhang, Mingda; Huang, Chongxiang; Xiao, Shuyang; Dong, Han; Weng, Yuqing

    2017-02-01

    Strength and toughness are a couple of paradox as similar as strength-ductility trade-off in homogenous materials, body-centered-cubic steels in particular. Here we report a simple way to get ultrahigh toughness without sacrificing strength. By simple alloying design and hot rolling the 5Mn3Al steels in ferrite/austenite dual phase temperature region, we obtain a series of ferrite/martensite laminated steels that show up-to 400–450J Charpy V-notch impact energy combined with a tensile strength as high as 1.0–1.2 GPa at room temperature, which is nearly 3–5 times higher than that of conventional low alloy steels at similar strength level. This remarkably enhanced toughness is mainly attributed to the delamination between ferrite and martensite lamellae. The current finding gives us a promising way to produce high strength steel with ultrahigh impact toughness by simple alloying design and hot rolling in industry.

  2. Visual analysis of ductility/brittleness of welding fracture points on charpy test specimens using graphical blocks on field programmable gate arrays

    NASA Astrophysics Data System (ADS)

    Tickle, Andrew J.; Camargo-Rodriguez, Anyela; Smith, Jeremy S.

    2008-09-01

    The charpy impact is a technique used to evaluate the toughness of an engineering material that determines the amount of energy absorbed by it during fracture. Initially, measurements were estimated manually and later replaced by a PC version. This study reports the development of the Field Programmable Gate Array (FPGA) portable version. The FPGA based version allows easy analysis of samples without the need of sending them to a lab for analysis. The process, presented here, as the original, is based on measuring the percent of crystal in the test sample after impact, to determine if the material is ductile or brittle. The FPGA version, adapted under the MATLAB Simulink environment, shows a graphical block representation of the charpy impact PC version. An important asset of the FPGA version is its portability, it has to be easily modified and downloaded onto a device to estimate the percent of brittle fracture of the broken Charpy surface. The beauty of the DSP Builder programme is that it allows the model to be compiled to various types of optimised code for any Altera FPGA device. To provide a firm basis for scientific comparison to the new FPGA system, images already analysed via the PC based Java system were also used for testing and comparison purposes. The FPGA system converts the image into an 8 bit grayscale image and analyses it in a 5x5 sampling window. This produces texture features that can be used in a comparison system, similar to the Support Vector Machine (SVM) used in the original. The output is a signal that states the material being tested is brittle or not via an output of '1' for brittle and a '0' for ductile. A detailed pixel by pixel analysis of the various output images is then investigated to state the percentage difference between the PC and FPGA based systems.

  3. Effects of Molybdenum and Vanadium Addition on Tensile and Charpy Impact Properties of API X70 Linepipe Steels

    NASA Astrophysics Data System (ADS)

    Kim, Young Min; Shin, Sang Yong; Lee, Hakcheol; Hwang, Byoungchul; Lee, Sunghak; Kim, Nack J.

    2007-08-01

    This study is concerned with the effects of V and Mo addition on tensile and Charpy impact properties of API X70 linepipe steels. Twelve kinds of steel specimens were produced by varying V and Mo additions and rolling conditions. The addition of V and Mo promoted the formation of acicular ferrite (AF), banitic ferrite (BF), and martensite-austenite (MA) constituents, while suppressing the formation of polygonal ferrite (PF) or pearlite (P). The tensile test results indicated that the tensile strength of the specimens rolled in the two-phase region increased with the addition of V and Mo, while the yield strength did not vary much in these specimens except the water-cooled specimens, which showed the increased yield strength with addition of Mo. The tensile strength of specimens rolled in the single-phase region followed by water cooling increased with increasing V and Mo contents. The yield strength, however, did not vary much with increasing V content or with addition of Mo to the low-V alloy. In these specimens, a substantial increase in the strengths was achieved only when Mo was added to the high-V alloy. The specimens rolled in the single-phase region had higher upper-shelf energy (USE) and lower ductile-brittle transition temperature (DBTT) than the specimens rolled in the two-phase region, because their microstructures were composed of AF and fine PF. According to the electron backscatter diffraction (EBSD) analysis data, the effective grain size in AF was determined by crystallographic packets composed of a few fine grains having similar orientations. Thus, the decreased DBTT in the specimens rolled in the single-phase region could be explained by the decrease in the overall effective grain size due to the presence of AF having smaller effective grain size.

  4. Charpy Impact Properties of Reduced-Activation Ferritic/Martensitic Steels Irradiated in HFIR up to 20 dpa

    SciTech Connect

    Tanigawa, H.; Shiba, K.; Sokolov, M.A.; Klueh, R.L.

    2003-07-15

    The effects of irradiation up to 20 dpa on the Charpy impact properties of reduced-activation ferritic/martensitic steels (RAFs) were investigated. The ductile-brittle transition temperature (DBTT) of F82H-IEA shifted up to around 323K. TIG weldments of F82H showed a fairly small variation on their impact properties. A finer prior austenite grain size in F82H-IEA after a different heat treatment resulted in a 20K lower DBTT compared to F82H-IEA after the standard heat treatment, and that effect was maintained even after irradiation. Helium effects were investigated utilizing Ni-doped F82H, but no obvious evidence of helium effects was obtained. ORNL9Cr-2WVTa and JLF-1 steels showed smaller DBTT shifts compared to F82H-IEA.

  5. Fracture Behavior of Ice in Charpy Impact Testing,

    DTIC Science & Technology

    1980-06-01

    S8 Single crystal ice ................................................................................ 8 Snow-ce...and stress-strain data. Several single crystal ice from the Mendenhall Glacier, Alaska, experiments are in progress at CRREL to supply addi- were used... ice . All artificial ice except corn- crystals are available, 3) slip occurs in most cases only mercial ice and mow- ice were grown in Lucite tubes. on

  6. Fracture toughness testing of Linde 1092 reactor vessel welds in the transition range using Charpy-sized specimens

    SciTech Connect

    Pavinich, W.A.; Yoon, K.K.; Hour, K.Y.; Hoffman, C.L.

    1999-10-01

    The present reference toughness method for predicting the change in fracture toughness can provide over estimates of these values because of uncertainties in initial RT{sub NDT} and shift correlations. It would be preferable to directly measure fracture toughness. However, until recently, no standard method was available to characterize fracture toughness in the transition range. ASTM E08 has developed a draft standard that shows promise for providing lower bound transition range fracture toughness using the master curve approach. This method has been successfully implemented using 1T compact fracture specimens. Combustion Engineering reactor vessel surveillance programs do not have compact fracture specimens. Therefore, the CE Owners Group developed a program to validate the master curve method for Charpy-sized and reconstituted Charpy-sized specimens for future application on irradiated specimens. This method was validated for Linde 1092 welds using unirradiated Charpy-sized and reconstituted Charpy-sized specimens by comparison of results with those from compact fracture specimens.

  7. Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 600 to 800

    SciTech Connect

    Fullam, H.T.

    1981-01-01

    The /sup 90/SrF/sub 2/ heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The /sup 90/SrF/sub 2/ heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the /sup 90/SrF/sub 2/ and Hastelloy C-276 inner capsule to a maximum of 800/sup 0/C. The outer capsule surface temperature will be somewhat less than 800/sup 0/C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 600/sup 0/ to 800/sup 0/C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 600/sup 0/ to 800/sup 0/C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 600/sup 0/ to 800/sup 0/C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 600/sup 0/ to 800/sup 0/C and control specimens heated in vacuum.

  8. A Microstructural Study on the Observed Differences in Charpy Impact Behavior Between Hot Isostatically Pressed and Forged 304L and 316L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Cooper, Adam J.; Cooper, Norman I.; Bell, Andrew; Dhers, Jean; Sherry, Andrew H.

    2015-11-01

    With near-net shape technology becoming a more desirable route toward component manufacture due to its ability to reduce machining time and associated costs, it is important to demonstrate that components fabricated via Hot Isostatic Pressing (HIP) are able to perform to similar standards as those set by equivalent forged materials. This paper describes the results of a series of Charpy tests from HIP'd and forged 304L and 316L austenitic stainless steel, and assesses the differences in toughness values observed. The pre-test and post-test microstructures were examined to develop an understanding of the underlying reasons for the differences observed. The as-received microstructure of HIP'd material was found to contain micro-pores, which was not observed in the forged material. In tested specimens, martensite was detectable within close proximity to the fracture surface of Charpy specimens tested at 77 K (-196 °C), and not detected in locations remote from the fracture surface, nor was martensite observed in specimens tested at ambient temperatures. The results suggest that the observed changes in the Charpy toughness are most likely to arise due to differences in as-received microstructures of HIP'd vs forged stainless steel.

  9. A generalized methodology for obtaining quantitative charpy data from test specimens of nonstandard dimensions

    SciTech Connect

    Manahan, M.P. ); Charles, C. , Inc., Washington, DC )

    1990-05-01

    Miniaturized specimen technology enables mechanical behavior determination using a minimum volume of material. A method for obtaining the ductile-brittle transition temperature (DBTT) of ferritic steels was developed using a miniaturized notch test (MNT). Comparisons between conventional and miniaturized specimen DBTTs show that the MNT specimens are capable of delivering a 41-J transition temperature shift with the same accuracy as that obtained using conventional specimens. The work reported was performed on an American Society for Testing Materials A508 steel.

  10. Charpy impact properties of low activation alloys for fusion applications after neutron irradiation

    NASA Astrophysics Data System (ADS)

    Rieth, M.; Dafferner, B.; Röhrig, H. D.

    1996-10-01

    The MANITU irradiation and fracture-toughness testing program although initially foreseen to clarify the early dose-saturation of ΔDBTT for commercial ferritic steels has been extended to include the medium temperature (≥ 250°C) irradiation hardening behaviour of promising low-activation alloys. The results after a first 0.8 dpa irradiation clearly show a much better behaviour of the new alloys in any respect (e.g. DBTT after irradiation always below +50°C for subsize specimens, for the ORNL steel even below -20°C). The complexity of temperature dependency is probably caused by the transition range in dose accumulation, and should therefore not be 'over-interpreted'.

  11. Effects of microstructural variation on Charpy impact properties in heavy-section Mn-Mo-Ni low alloy steel for reactor pressure vessel

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin; Song, Jaemin; Kim, Min-Chul; Choi, Kwon-Jae; Lee, Bong-Sang

    2016-03-01

    The effects of microstructural changes in heavy-section Mn-Mo-Ni low alloy steel on Charpy impact properties were investigated using a 210 mm thick reactor pressure vessel. Specimens were sampled from 5 different positions at intervals of 1/4 thickness from the inner surface to the outer surface. A detailed microstructural analysis of impact-fractured specimens showed that coarse carbides along the lath boundaries acted as fracture initiation sites, and cleavage cracks deviated at prior-austenite grain boundaries and bainite lath boundaries. Upper shelf energy was higher and energy transition temperature was lower at the surface positon, where fine bainitic microstructure with homogeneously distributed fine carbides were present. Toward the center, coarse upper bainite and precipitation of coarse inter-lath carbides were observed, which deteriorated impact properties. At the 1/4T position, the Charpy impact properties were worse than those at other positions owing to the combination of elongated-coarse inter-lath carbides and large effective grain size.

  12. Transverse and z-Direction CVN Impact Tests of X65 Line Pipe Steels of Two Centerline Segregation Ratings

    NASA Astrophysics Data System (ADS)

    Su, Lihong; Li, Huijun; Lu, Cheng; Li, Jintao; Fletcher, Leigh; Simpson, Ian; Barbaro, Frank; Zheng, Lei; Bai, Mingzhuo; Shen, Jianlan; Qu, Xianyong

    2016-08-01

    Centerline segregation occurs as a positive concentration of alloying elements in the mid-thickness region of continuously cast slab. Depending upon its severity, it may affect mechanical properties and potentially downstream processing such as weldability, particularly for high-strength line pipe. The segregation fraction in continuously cast slabs and corresponding hot-rolled strips was assessed on API 5L grade X65 line pipe steels with different levels of segregation, rated as Mannesmann 2.0 and 1.4. The results showed that the segregation fraction in hot-rolled strip samples was in accordance with that assessed in the cast slabs, and the segregated regions in hot-rolled strip samples were found to be discontinuous. Transverse and z-direction CVN impact tests were conducted on the two strips and the results showed that centerline segregation does have an influence on the Charpy impact properties of line pipe steel. Specimens located at segregated regions exhibited lower Charpy impact toughness and strips rolled from slabs with higher segregation levels are more likely to exhibit greater variability in Charpy impact toughness. The influence of centerline segregation on z-direction Charpy impact toughness is more severe than on transverse Charpy impact toughness. Lower Charpy impact toughness and brittle fracture surface with cleavage facets along with rod-shaped MnS inclusions were observed for the strip rolled from slab with 2.0 segregation rating if the Charpy specimens were located at segregated regions. The influence on Charpy impact toughness can be associated with the pearlite structure at the centerline and level of MnS inclusions.

  13. Assessment of Ductile-to-Brittle Transition Behavior of Localized Microstructural Regions in a Friction-Stir Welded X80 Pipeline Steel with Miniaturized Charpy V-Notch Testing

    NASA Astrophysics Data System (ADS)

    Avila, Julian A.; Lucon, Enrico; Sowards, Jeffrey; Mei, Paulo Roberto; Ramirez, Antonio J.

    2016-06-01

    Friction-stir welding (FSW) is an alternative welding process for pipelines. This technology offers sound welds, good repeatability, and excellent mechanical properties. However, it is of paramount importance to determine the toughness of the welds at low temperatures in order to establish the limits of this technology. Ductile-to-brittle transition curves were generated in the present study by using a small-scale instrumented Charpy machine and miniaturized V-notch specimens (Kleinstprobe, KLST); notches were located in base metal, heat-affected, stirred, and hard zones within a FSW joint of API-5L X80 Pipeline Steel. Specimens were tested at temperatures between 77 K (-196 °C) and 298 K (25 °C). Based on the results obtained, the transition temperatures for the base material and heat-affected zone were below 173 K (-100 °C); conversely, for the stirred and hard zones, it was located around 213 K (-60 °C). Fracture surfaces were characterized and showed a ductile fracture mechanism at high impact energies and a mixture of ductile and brittle mechanisms at low impact energies.

  14. Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens

    PubMed Central

    Lucon, Enrico; McCowan, Chris N.; Santoyo, Ray L.

    2015-01-01

    The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of −40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots considered, the observed variability was lower at 21 °C than at −40 °C. The results of this study will allow NIST to satisfy requests for room-temperature Charpy verification specimens that have been received from customers for several years: testing at 21 °C removes from the verification process the operator’s skill in transferring the specimen in a timely fashion from the cooling bath to the impact position, and puts the focus back on the machine performance. For NIST, it also reduces the time and cost for certifying new verification lots. For one of the low-energy lots tested with a C-shaped hammer, we experienced two specimens jamming, which yielded unusually high values of absorbed energy. For both specimens, the signs of jamming were clearly visible. For all the low-energy lots investigated, jamming is slightly more likely to occur at 21 °C than at −40 °C, since at room temperature low-energy samples tend to remain in the test area after impact rather than exiting in the opposite direction of the pendulum swing. In the evaluation of a verification set, any jammed specimen should be removed from the analyses. PMID:26958453

  15. Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens.

    PubMed

    Lucon, Enrico; McCowan, Chris N; Santoyo, Ray L

    2015-01-01

    The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of -40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots considered, the observed variability was lower at 21 °C than at -40 °C. The results of this study will allow NIST to satisfy requests for room-temperature Charpy verification specimens that have been received from customers for several years: testing at 21 °C removes from the verification process the operator's skill in transferring the specimen in a timely fashion from the cooling bath to the impact position, and puts the focus back on the machine performance. For NIST, it also reduces the time and cost for certifying new verification lots. For one of the low-energy lots tested with a C-shaped hammer, we experienced two specimens jamming, which yielded unusually high values of absorbed energy. For both specimens, the signs of jamming were clearly visible. For all the low-energy lots investigated, jamming is slightly more likely to occur at 21 °C than at -40 °C, since at room temperature low-energy samples tend to remain in the test area after impact rather than exiting in the opposite direction of the pendulum swing. In the evaluation of a verification set, any jammed specimen should be removed from the analyses.

  16. Fractographic examination of reduced activation ferritic/martensitic steel charpy specimens irradiated to 30 dpa at 370{degrees}C

    SciTech Connect

    Gelles, D.S.; Hamilton, M.L.; Schubert, L.E.

    1996-10-01

    Fractographic examinations are reported for a series of reduced activation ferritic/Martensitic steel Charpy impact specimens tested following irradiation to 30 dpa at 370{degrees}C in FFTF. One-third size specimens of six low activation steels developed for potential application as structural materials in fusion reactors were examined. A shift in brittle fracture appearance from cleavage to grain boundary failure was noted with increasing manganese content. The results are interpreted in light of transmutation induced composition changes in a fusion environment.

  17. The effect of fibre content, fibre size and alkali treatment to Charpy impact resistance of Oil Palm fibre reinforced composite material

    NASA Astrophysics Data System (ADS)

    Fitri, Muhamad; Mahzan, Shahruddin

    2016-11-01

    In this research, the effect of fibre content, fibre size and alkali treatment to the impact resistance of the composite material have been investigated, The composite material employs oil palm fibre as the reinforcement material whereas the matrix used for the composite materials are polypropylene. The Oil Palm fibres are prepared for two conditions: alkali treated fibres and untreated fibres. The fibre sizes are varied in three sizes: 5mm, 7mm and 10mm. During the composite material preparation, the fibre contents also have been varied into 3 different percentages: 5%, 7% and 10%. The statistical approach is used to optimise the variation of specimen determined by using Taguchi method. The results were analyzed also by the Taguchi method and shows that the Oil Palm fibre content is significantly affect the impact resistance of the polymer matrix composite. However, the fibre size is moderately affecting the impact resistance, whereas the fibre treatment is insignificant to the impact resistance of the oil palm fibre reinforced polymer matrix composite.

  18. Performance verification of impact machines for testing plastics

    SciTech Connect

    Siewert, T.A.; Vigliotti, D.P.; Dirling, L.B.; McCowan, C.N.

    1999-12-01

    Valid comparison of impact test energies reported by various organizations and over time depends on consistent performance of impact test machines. This paper investigates the influence of various specimen and test parameters on impact energies in the 1 J to 2 J range for both Charpy V-notch and Izod procedures, leading toward the identification of a suitable material for use in a program to verify machine performance. The authors investigated the influences on the absorbed energy of machine design, test material, specimen cross sectional area, and machine energy range. For comparison to published round robin data on common plastics, this study used some common metallic alloys, including those used in the international verification program for metals impact machines and in informal calibration programs of tensile machines. The alloys that were evaluated include AISI type 4340 steel, and five aluminum alloys: 2014-T6, 2024-T351, 2219-T87, 6061-T6, and 7075-T6. They found that certain metallic alloys have coefficients of variation comparable to those of the best plastics that are reported in the literature. Also, they found that the differences in absorbed energy between two designs of machines are smaller than the differences that can be attributed to the specimens alone.

  19. Use of precracked Charpy and smaller specimens to establish the master curve

    SciTech Connect

    Sokolov, M.A.; McCabe, D.E.; Nanstad, R.K.; Davidov, Y.A.

    1997-12-01

    The current provisions used in the U.S. Code of Federal Regulations for the determination of the fracture toughness of reactor pressure vessel steels employs an assumption that there is a direct correlation between K{sub Ic} lower-bound toughness and the Charpy V-notch transition curve. Such correlations are subject to scatter from both approaches which weakens the reliability of fracture mechanics-based analyses. In this study, precracked Charpy and smaller size specimens are used in three-point static bend testing to develop fracture mechanics based K{sub k} values. The testing is performed under carefully controlled conditions such that the values can be used to predict the fracture toughness performance of large specimens. The concept of a universal transition curve (master curve) is applied. Data scatter that is characteristic of commercial grade steels and their weldments is handled by Weibull statistical modeling. The master curve is developed to describe the median K{sub Jc} fracture toughness for 1T size compact specimens. Size effects are modeled using weakest-link theory and are studied for different specimen geometries. It is shown that precracked Charpy specimens when tested within their confined validity limits follow the weakest-link size-adjustment trend and predict the fracture toughness of larger specimens. Specimens of smaller than Charpy sizes (5 mm thick) exhibit some disparities in results relative to weakest-link size adjustment prediction suggesting that application of such adjustment to very small specimens may have some limitations.

  20. 46 CFR 54.05-17 - Weld toughness test acceptance criteria.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Weld toughness test acceptance criteria. 54.05-17... PRESSURE VESSELS Toughness Tests § 54.05-17 Weld toughness test acceptance criteria. (a) For Charpy V-notch impact tests the energy absorbed in both the weld metal and heat affected zone impact tests in...

  1. 46 CFR 54.05-5 - Toughness test specimens.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    .... If the drop-weight test cannot be performed because of material thickness limitations (less than one... reference, see § 54.01-1), “Notched Bar Impact Testing of Metallic Materials”, using the Type A specimen... used to qualify materials within the scope of this subpart. Each set of Charpy impact tests...

  2. 46 CFR 54.05-5 - Toughness test specimens.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    .... If the drop-weight test cannot be performed because of material thickness limitations (less than one... reference, see § 54.01-1), “Notched Bar Impact Testing of Metallic Materials”, using the Type A specimen... used to qualify materials within the scope of this subpart. Each set of Charpy impact tests...

  3. Impact tests of the tungsten coated stainless steels prepared by using magnetron sputtering with ion beam mixing or electron beam alloying treatment

    NASA Astrophysics Data System (ADS)

    Zou, Yu; Zhan, Chang-Yong; Yang, Bin; Wu, Jian-Chun

    2013-05-01

    Tungsten films were deposited on stainless steel (SS) with ion beam mixing (IBM) or electron beam alloying (EBA) treatment. The ductile-brittle transition behaviors of the specimens were investigated by means of instrumented Charpy impact test at a series of temperature, and SEM was used to observe the morphology of the cross section. Impact tests show that different treatment methods with W films do not have much influence on crack initiation, while EBA treatment with W films can more effectively prevent crack propagation, namely improve the impact toughness of SS than using IBM treatment. The reason that caused this difference was discussed.

  4. Effect of angleplying and matrix enhancement on impact-resistant boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Signorelli, R. A.

    1976-01-01

    Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Tensile and dynamic modulus tests, thin sheet Charpy and Izod impact tests, and standard full size Charpy impact tests were conducted on 0.20 mm (8 mil) diameter-B/1100 Al matrix composites. Angleplies ranged from unidirectional to + or - 30 deg. The best compromise between reduced longitudinal properties and increased transverse properties was obtained with + or - 15 deg angleply. The pendulum impact strengths of improved B/Al were higher than that of notched titanium and appear to be enough to warrant consideration of B/Cl for application to fan blades in aircraft gas turbine engines.

  5. Estimation of Ksub Ic from slow bend precracked Charpy specimen strength ratios

    NASA Technical Reports Server (NTRS)

    Succop, G.; Brown, W. F., Jr.

    1976-01-01

    Strength ratios are reported which were derived from slow bend tests on 0.25 inch thick precracked Charpy specimens of steels, aluminum alloys, and a titanium alloy for which valid K sub Ic values were established. The strength ratios were used to develop calibration curves typical of those that could be useful in estimating K sub Ic for the purposes of alloy development of quality control.

  6. Southern Impact Testing Alliance (SITA)

    NASA Technical Reports Server (NTRS)

    Hubbs, Whitney; Roebuck, Brian; Zwiener, Mark; Wells, Brian

    2009-01-01

    Efforts to form this Alliance began in 2008 to showcase the impact testing capabilities within the southern United States. Impact testing customers can utilize SITA partner capabilities to provide supporting data during all program phases-materials/component/ flight hardware design, development, and qualification. This approach would allow programs to reduce risk by providing low cost testing during early development to flush out possible problems before moving on to larger scale1 higher cost testing. Various SITA partners would participate in impact testing depending on program phase-materials characterization, component/subsystem characterization, full-scale system testing for qualification. SITA partners would collaborate with the customer to develop an integrated test approach during early program phases. Modeling and analysis validation can start with small-scale testing to ensure a level of confidence for the next step large or full-scale conclusive test shots. Impact Testing Facility (ITF) was established and began its research in spacecraft debris shielding in the early 1960's and played a malor role in the International Space Station debris shield development. As a result of return to flight testing after the loss of STS-107 (Columbia) MSFC ITF realized the need to expand their capabilities beyond meteoroid and space debris impact testing. MSFC partnered with the Department of Defense and academic institutions as collaborative efforts to gain and share knowledge that would benefit the Space Agency as well as the DoD. MSFC ITF current capabilities include: Hypervelocity impact testing, ballistic impact testing, and environmental impact testing.

  7. A study of the fracture process and factors that control toughness variability in Charpy V-notch specimens

    NASA Astrophysics Data System (ADS)

    Bouchard, Real

    La presente etude a ete initiee pour developper une comprehension quantitative du processus de rupture avec les facteurs qui controlent la dispersion des mesures de tenacite lorsque des eprouvettes Charpy entaillees en V sont utilisees. Un grand nombre d'essais ont ete realises pour un acier C-Mn: eprouvettes Charpy testees sous impact, eprouvettes Charpy testees en flexion lente, eprouvettes axisymetriques entaillees et sollicitees en traction et essais de tenacite sur eprouvettes prefissurees. Base sur le concept de la statistique de Weibull, l'approche locale developpee par le groupe Beremin a ete utilisee pour decrire la probabilite de rupture par clivage en fonction de la contrainte appliquee aussi bien qu'en fonction de l'energie Charpy obtenue. Le calcul par elements finis a ete realise pour determiner la distribution de la deformation et des contraintes en pointe d'entaille et de fissure. La nouvelle approche introduite decrit bien les resultats experimentaux. Les points d'initiation du clivage ont ete identifies au MEB et par la suite, avec la technique de faisceau d'ions focalise, sectionnes, polis et examines. L'examen de la microstructure sous le point d'initiation revele clairement que le clivage s'initie par un mecanisme d'empilement de dislocations ou les dislocations sont arretees aux joints de grain, aux interfaces de perlite/ferrite ou de perlite qui agissent comme barrieres physiques.

  8. Testing Impact?s Radiation Code

    SciTech Connect

    Edis, T; Cameron-Smith, P; Grant, K E; Bergmann, D; Chuang, C C

    2004-07-12

    This is a summary of work done over an 8 week period from May to July 2004, which concerned testing the longwave and shortwave radiation packages in Impact. The radiation code was initially developed primarily by Keith Grant in the context of LLNL's 2D model, and was added to Impact over the last few summers. While the radiation code had been tested and also used in some aerosol-related calculations, its 3D form in Impact had not been validated with comparisons to satellite data. Along with such comparisons, our work described here was also motivated by the need to validate the radiation code for use in the SciDAC consortium project. This involved getting the radiation code working with CAM/WACCM met data, and setting the stage for comparing CAM/WACCM radiation output with Impact results.

  9. Hypervelocity impact testing of tethers

    NASA Technical Reports Server (NTRS)

    Woodis, William R.; Tallentire, Francis I.

    1988-01-01

    An experimental test program has been conducted to ascertain the strength losses to which representative space tether materials may be prone upon impact by hypervelocity particles of known size, density, and velocity, when the tether is under tensile loading typical of flight design loads. Twelve hypervelocity impacts were followed by tensile tests to failure to determine residual strength; relationships are established between particle velocity and strength loss due to impact damage, as well as between tether strength loss and the relationship between particle and tether diameters. Tentative design criteria are formulated in terms of a design factor allowing for strength degradation by impact.

  10. Impacting device for testing insulation

    NASA Technical Reports Server (NTRS)

    Redmon, J. W. (Inventor)

    1984-01-01

    An electro-mechanical impacting device for testing the bonding of foam insulation to metal is descirbed. The device lightly impacts foam insulation attached to metal to determine whether the insulation is properly bonded to the metal and to determine the quality of the bond. A force measuring device, preferably a load cell mounted on the impacting device, measures the force of the impact and the duration of the time the hammer head is actually in contact with the insulation. The impactor is designed in the form of a handgun having a driving spring which can propel a plunger forward to cause a hammer head to impact the insulation. The device utilizes a trigger mechanism which provides precise adjustements, allowing fireproof operation.

  11. Tensile and impact behavior of the reduced-activation steels OPTIFER and F82H mod

    NASA Astrophysics Data System (ADS)

    Schäfer, L.

    2000-12-01

    Tensile and charpy impact tests were carried out on some OPTIFER steel grades and F82H mod. The steels show little difference in tensile properties, but pronounced differences in charpy impact properties. Combinations of low ductile-brittle transition temperature (DBTT) and high yield strength are favored for OPTIFER-IV. After aging at 600°C and higher, F82H mod steel embrittles due to precipitation of Laves phase (Cr, Fe)2W, whereas OPTIFER-IV is resistant to aging.

  12. Charpy toughness and tensile properties of a neutron irradiated stainless steel submerged-arc weld cladding overlay

    SciTech Connect

    Corwin, W.R.; Berggren, R.G.; Nanstad, R.K.

    1984-01-01

    The possibility of stainless steel cladding increasing the resistance of an operating nuclear reactor pressure vessel to extension of surface flaws is highly dependent upon the irradiated properties of the cladding. Therefore, weld overlay cladding irradiated at temperatures and fluences relevant to power reactor operation was examined. The cladding was applied to a pressure vessel steel plate by the submerged-arc, single-wire, oscillating electrode method. Three layers of cladding were applied to provide a cladding thickness adequate for fabrication of test specimens. The first layer was type 309, and the upper two layers were type 308 stainless steel. There was considerable dilution of the type 309 in the first layer of cladding as a result of excessive melting of the base plate. Specimens for the irradiation study were taken from near the base plate/cladding interface and also from the upper layers of cladding. Charpy V-notch and tensile specimens were irradiated at 288/sup 0/C to neutron fluences of 2 x 10/sup 23/ n/m/sup 2/ (E > 1 MeV). When irradiated, both types 308 and 309 cladding showed a 5 to 40% increase in yield strength accompanied by a slight increase in ductility in the temperature range from 25 to 288/sup 0/C. All cladding exhibited ductile-to-brittle transition behavior during impact testing.

  13. Numerical and experimental evaluation of the impact performance of advanced high-strength steel sheets based on a damage model

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Park, Taejoon; Kim, Dongun; Kim, Chongmin; Chung, Kwansoo

    2010-06-01

    The impact performance in a Charpy impact test was experimentally and numerically studied for the advanced high-strength steel sheets (AHSS) TWIP940 and TRIP590 as well as the high-strength grade known as 340R. To characterize the mechanical properties, uni-axial simple tension tests were conducted to determine the anisotropic properties and strain rate sensitivities of these materials. In particular, the high-speed strain-rate sensitivity of TRIP590 and 340R (rate sensitive) was also characterized to account for the high strain rates involved in the Charpy impact test. To evaluate fracture behavior in the Charpy impact test, a new damage model including a triaxiality-dependent fracture criterion and hardening behavior with stiffness deterioration was introduced. The model was calibrated via numerical simulations and experiments involving simple tension and V-notch tests. The new damage model along with the anisotropic yield function Hill 1948 was incorporated into the ABAQUS/Explicit FEM code, which performed reasonably well to predict the impact energy absorbed during the Charpy impact test.

  14. Prediction of yield stress and Charpy transition temperature in highly neutron irradiated ferritic steels

    NASA Astrophysics Data System (ADS)

    Windsor, Colin; Cottrell, Geoff; Kemp, Richard

    2010-07-01

    Recent predictions have been made of metallurgical properties of low-activation ferritic/martensitic steels alloys at the high irradiation levels (displacements per atom or dpa) needed for a fusion power plant as based on measurements at low irradiation levels where more data are available. These predictions have been published for the yield stress and for the Charpy ductile to brittle transition temperature shift. The neural network model predictions use training data up to a certain dpa level to predict metallurgical properties above this level. This 'extrapolation' mode of neural networks is explored in some detail. Our studies revealed an increasing accuracy of predictions as the test dpa level is increased for both yield stress and Charpy shift predictions. This result suggests that a model exists for these metallurgical properties as a function of dpa level which becomes more accurate as the available irradiation range in the training data is increased. The explanation suggested is that the metallurgical annealing, which occurs as the irradiation level is increased, simplifies the microstructure and makes prediction more reliable.

  15. Design, Fabrication and Test of Multi-Fiber Laminates

    NASA Technical Reports Server (NTRS)

    Pike, R. A.; Novak, R. C.

    1975-01-01

    Unidirectional and angleply multifiber laminates were tested for improved impact strength and other mechanical properties. The effects of several variables on the mechanical properties of epoxy matrix materials were described. These include fiber type (HMS and AS graphites, glass, and Kevlar 49), ratio of primary to hybridizing fiber and hybrid configuration. It is demonstrated that AS graphite/S glass in an intraply configuration results in the best combination of static and Charpy impact properties as well as superior ballistic impact resistance. Pendulum impact tests which were conducted on thin specimens are shown to produce different ranking of materials than tests conducted on standard thickness Charpy specimens. It is shown that the thin specimen results are in better agreement with the ballistic impact data. Additional static test data are reported as a function of temperature for the seven best hybrid configurations having epoxy, polyimide (PMR-15) and polyphenylquinoxaline resins as the matrix.

  16. Low temperature impact testing of welded structural wrought iron

    NASA Astrophysics Data System (ADS)

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  17. Glatz Prototype Seat Impact Testing

    DTIC Science & Technology

    2013-07-03

    all PH testing. The HIA consists of a 4 ft by 8 ft sled positioned on a 204 ft long track and is accelerated using a 24 inch diameter pneumatic ...thrust piston, the sled coasts to a stop or is stopped with a triggered pneumatic brake system. The impact acceleration is roughly sinusoidal. HIA... Hybrid III Aerospace manikin (HB50) representing a mid-sized male, and a Large Anthropomorphic Research Device (LARD) manikin representing a large male

  18. Mechanical properties test data of Alloy 718 for liquid metal fast breeder reactor applications

    SciTech Connect

    Korth, G.E.

    1983-01-01

    Mechanical property test data are reported for Alloy 718 with two heat treatments: conventional heat treatment (CHT) for base metal and Idaho National Engineering Laboratory (INEL) heat treatment (IHT) for base and weld metal. Tests were conducted in air from 24 to 704{degree}C and include elastic properties (Young's modulus, shear modulus, Poisson's ratio), tensile properties, creep-rupture properties, fatigue properties, creep-fatigue properties, and Charpy impact behavior. Effects of long term thermal aging at 538, 593, 649, and 704{degree}C for times to 25,000 h are also reported for CHT material (tensile, creep-rupture, fatigue, and Charpy), and IHT material (tensile, and Charpy). 18 refs., 63 figs., 36 tabs.

  19. Ares I-X USS Material Testing

    NASA Technical Reports Server (NTRS)

    Dawicke, David S.; Smith, Stephen W.; Raju, Ivatury S.

    2008-01-01

    An independent assessment was conducted to determine the critical initial flaw size (CIFS) for the flange-to-skin weld in the Ares I-X Upper Stage Simulator (USS). Material characterization tests were conducted to quantify the material behavior for use in the CIFS analyses. Fatigue crack growth rate, Charpy impact, and fracture tests were conducted on the parent and welded A516 Grade 70 steel. The crack growth rate tests confirmed that the material behaved in agreement with literature data and that a salt water environment would not significantly degrade the fatigue resistance. The Charpy impact tests confirmed that the fracture resistance of the material did not have a significant reduction for the expected operational temperatures of the vehicle.

  20. Improved impact-resistant boron-aluminum composites for use as turbine engine fan blades

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Signorelli, R. A.

    1976-01-01

    Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Thin sheet Charpy and Izod impact tests and standard full size Charpy impact tests were conducted on unidirectional and angleply composites containing 4, 5.6 and 8 mil boron in 1100, 2024, 5052 and 6061 Al matrices. Impact failure modes of B/Al are proposed in an attempt to describe the mechanisms involved and to provide insight for maximizing impact resistance. The impact strength of B/Al was significantly increased by proper selection of materials and processing. The use of more ductile matrices (1100 Al) and larger diameter (8 mil) boron fibers gave the highest impact strengths by allowing matrix shear deformation and multiple fiber breakage.

  1. Effect of fiber diameter and matrix alloys on impact-resistant boron/aluminum composites

    NASA Technical Reports Server (NTRS)

    Mcdanels, D. L.; Signorelli, R. A.

    1976-01-01

    Efforts to improve the impact resistance of B/Al are reviewed and analyzed. Nonstandard thin-sheet charpy and Izod impact tests and standard full-size Charpy impact tests were conducted on composites containing unidirectional 0.10mm, 0.14mm, and 0.20mm diameter boron fibers in 1100, 2024, 5052, and 6061 Al matrices. Impact failure modes of B/Al are proposed in an attempt to describe the mechanisms involved and to provide insight for maximizing impact resistance. The impact strength of B/Al was significantly increased by proper selection of materials and processing. The use of a ductile matrix and large diameter boron fibers gave the highest impact strengths. This combination resulted in improved energy absorption through matrix shear deformation and multiple fiber breakage.

  2. High Pressure Quick Disconnect Particle Impact Tests

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact testing to determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). Testing included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This paper summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs. KEYWORDS: quick disconnect, high pressure, particle impact testing, stainless steel

  3. Supersonic Particle Impact Test Capabilities: Investigative Report

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa

    2007-01-01

    NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact flow tests to determine the maximum capabilities of the particle impact test systems in different configurations. Additional flow tests were performed to determine the target pressures at given upstream conditions to supplement the WSTF data located in ASTM Manual 36 (2000).

  4. High Pressure Quick Disconnect Particle Impact Tests

    NASA Technical Reports Server (NTRS)

    Peralta, Stephen; Rosales, Keisa; Smith, Sarah R.; Stoltzfus, Joel M.

    2007-01-01

    To determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS), NASA Johnson Space Center requested White Sands Test Facility (WSTF) to perform particle impact testing. Testing was performed from November 2006 through May 2007 and included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This report summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs.

  5. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Impact test. 7.46 Section 7.46 Mineral... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force...

  6. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Impact test. 7.46 Section 7.46 Mineral... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force...

  7. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Impact test. 7.46 Section 7.46 Mineral... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force...

  8. Hypervelocity impact testing of cables

    NASA Technical Reports Server (NTRS)

    Jex, D. W.; Adkinson, A. B.; English, J. E.; Linebaugh, C. E.

    1973-01-01

    The physics and electrical results obtained from simulated micrometeoroid testing of certain Skylab cables are presented. The test procedure, electrical circuits, test equipment, and cable types utilized are also explained.

  9. Impact of Test Disclosure Legislation on Test Development.

    ERIC Educational Resources Information Center

    Fremer, John

    Test disclosure legislation in New York State (LaValle Act) has had a major impact on the national testing programs administered by Educational Testing Services (ETS) for various sponsoring organizations. The paper reviews the immediate operational effects of test disclosure in the following areas: (1) increase in number of test forms developed;…

  10. Impact properties of the aircraft cast aluminium alloy Al-7Si0.6Mg (A357)

    NASA Astrophysics Data System (ADS)

    Alexopoulos, N. D.

    2010-06-01

    The impact mechanical properties of the widely used in the aeronautics A357 cast aluminum alloy were investigated by exploiting experiments on an instrumented Charpy impact testing machine. The evaluated impact properties for 25 different artificial aging heat treatment conditions were analyzed and discussed in conjunction with the respective tensile properties. Correlations are proposed to establish useful relationships between impact resistance and tensile strain energy density properties. The established correlations, which are well supported by the performed experiments, can be used to estimate the tensile ductility and toughness of the A357 cast aluminum alloy from the Charpy impact test. Performed fractographic analyses were supporting the physically arbitrary correlation between tensile strain energy density and impact resistance.

  11. Clean Cast Steel Technology: Effect of Micro-porosity on Tensile and Charpy Properties of Four Cast Steels

    SciTech Connect

    Griffin, John, A.; Bates, Charles, E.

    2005-09-19

    The effect of these large shrink cavities on mechanical properties could be easily calculated using well established engineering formulas. Over the years, increases in computational and metallurgical resources have allowed the modeler to improve accuracy and increase the complexity of numerical predictors. An accurate prediction of micro-porosity, not observable using conventional radiographic techniques, and an engineering understanding of the effect on mechanical properties would give a designer confidence in using a more efficient casting design and a lower safety factor. This will give castings an additional design advantage. The goal of this project is to provide current and future modelers/designers with a tensile and Charpy property dataset for validation of micro-porosity predictors. The response of ultimate strength, elongation, and reduction in area to micro-porosity was very similar in all four alloys. Ultimate strength was largely unaffected by tensile fracture surface porosity until values of about 25% were reached and decreased linearly with increasing values. Elongation and reduction in area decreased sharply after less than 5% fracture surface porosity. Niyama values of about 0.7 were produced sound material and acceptable tensile properties. Ultrasonic velocities of 0.233 in/usec and higher produced acceptable tensile properties. Metallographic examination revealed a ratio of 4-6 to 1 in fracture surface porosity to metallographic porosity. Charpy impact properties were largely unaffected by the microporosity concentrations examined in this study and did not correlate to either Niyama values, fracture surface porosity, or metallographic porosity.

  12. Solid rocket booster water impact test

    NASA Technical Reports Server (NTRS)

    Bugg, F.

    1982-01-01

    Water impact drop tests were performed on the space shuttle solid rocket boosters (SRB). Peak water impact pressures and pressure/time traces were measured for various impact velocities using a two-dimensional, full-scale SRB aft skirt internal ring model. Passive burst disc-type pressure transducers were calibrated for use on flight SRB's. The effects on impact pressure of small ring configuration changes and application of thermal protection system cork layers were found to be negligible.

  13. Water impact shock test system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The basic objective was to design, manufacture, and install a shock test system which, in part, would have the ability to subject test articles weighing up to 1,000 pounds to both half sine and/or full sine pulses having peak levels of up to 50 G's with half sine pulse durations of 100 milliseconds or full sine period duration of 200 milliseconds. The tolerances associated with the aforementioned pulses were +20% and -10% for the peak levels and plus or minus 10% for the pulse durations. The subject shock test system was to be capable of accepting test article sizes of up to 4 feet by 4 feet mounting surface by 4 feet in length.

  14. Impact Testing of Stainless Steel Materials

    SciTech Connect

    R. K. Blandford; D. K. Morton; T. E. Rahl; S. D. Snow

    2005-07-01

    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 (10 to 200 per second) during accidental drop events. Mechanical characteristics of these materials under dynamic (impact) loads in the strain rate range of concern are not well documented. The goal of the work presented in this paper was to improve understanding of moderate strain rate phenomena on these materials. Utilizing a drop-weight impact test machine and relatively large test specimens (1/2-inch thick), initial test efforts focused on the tensile behavior of specific stainless steel materials during impact loading. Impact tests of 304L and 316L stainless steel test specimens at two different strain rates, 25 per second (304L and 316L material) and 50 per second (304L material) were performed for comparison to their quasi-static tensile test properties. Elevated strain rate stress-strain curves for the two materials were determined using the impact test machine and a “total impact energy” approach. This approach considered the deformation energy required to strain the specimens at a given strain rate. The material data developed was then utilized in analytical simulations to validate the final elevated stress-strain curves. The procedures used during testing and the results obtained are described in this paper.

  15. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... at 122 °F (50 °C) for a period of 48 hours. (2) Mount the covers on a battery box of the same design with which the covers are to be approved, including any support blocks, with the battery...

  16. Permeability After Impact Testing of Composite Laminates

    NASA Technical Reports Server (NTRS)

    Nettles, A.T.; Munafo, Paul (Technical Monitor)

    2002-01-01

    Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a non-linear fashion for almost all of the specimens tested.

  17. Permeability After Impact Testing of Composite Laminates

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    2003-01-01

    Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a non-linear fashion for almost all of the specimens tested.

  18. Impact testing of textile composite materials

    NASA Technical Reports Server (NTRS)

    Portanova, Marc

    1995-01-01

    The objectives of this report were to evaluate the impact damage resistance and damage tolerance of a variety of textile composite materials. Static indentation and impact tests were performed on the stitched and unstitched uniweave composites constructed from AS4/3501-6 Carbon/Epoxy with a fiberglass yarn woven in to hold the fibers together while being stitched. Compression and tension were measured after the tests to determine the damage resistance, residual strength and the damage tolerance of the specimens.

  19. DebriSat Hypervelocity Impact Test

    DTIC Science & Technology

    2015-08-01

    10. SPONSOR/MONITOR’S ACRONYM(S) NASA Orbital Debris Program Office Attn: Dr. J.C. Liou 2101 NASA Parkway Houston, TX 77058 11. SPONSOR...of providing information on the physics of the entire impact event. 15. Subject Terms Orbital debris ; light gas gun; AEDC Range G; hypervelocity...based on the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT) project in the AEDC Range G facility (Ref. 1). This previous test

  20. Hypervelocity impact testing of spacecraft optical sensors

    SciTech Connect

    1995-07-01

    Hypervelocity tests of spacecraft optical sensors were conducted to determine if the optical signature from an impact inside the optical sensor sunshade resembled signals that have been observed on-orbit. Impact tests were conducted in darkness and with the ejected debris illuminated. The tests were conducted at the Johnson Space Center Hypervelocity Impact Test Facility. The projectile masses and velocities that may be obtained at the facility are most representative of the hypervelocity particles thought to be responsible for a group of anomalous optical sensors responses that have been observed on-orbit. The projectiles are a few micrograms, slightly more massive than the microgram particles thought to be responsible for the signal source. The test velocities were typically 7.3 km/s, which are somewhat slower than typical space particles.

  1. Visualization of impact damaging of carbon/epoxy panels

    NASA Astrophysics Data System (ADS)

    Boccardi, Simone; Boffa, Natalino Daniele; Carlomagno, Giovanni Maria; Meola, Carosena; Ricci, Fabrizio

    2016-05-01

    This work is concerned with impact damaging of carbon/epoxy materials. Specimens of different thickness are herein considered, which involve several fibers orientations and stacking sequences. Impact tests are carried out at different energies with a modified Charpy pendulum. The specimen surface opposite to that struck by the impactor is viewed by an infrared imaging device. Then, a sequence of thermal images is acquired during each impact test. Through the temperature variations experienced by the specimen surface, post-processing of such images supplies the likely occurred damage. In addition, specimens are non-destructively evaluated with lock-in thermography to visualize any manufacturing defects, as well as impact damage.

  2. Tests of the Giant Impact Hypothesis

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1998-01-01

    The giant impact hypothesis has gained popularity as a means of explaining a volatile-depleted Moon that still has a chemical affinity to the Earth. As Taylor's Axiom decrees, the best models of lunar origin are testable, but this is difficult with the giant impact model. The energy associated with the impact would be sufficient to totally melt and partially vaporize the Earth. And this means that there should he no geological vestige of Barber times. Accordingly, it is important to devise tests that may be used to evaluate the giant impact hypothesis. Three such tests are discussed here. None of these is supportive of the giant impact model, but neither do they disprove it.

  3. FOD impact testing of composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

    The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin, and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.

  4. FOD impact testing of composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

    The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.

  5. Impact testing on composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

    The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.

  6. Mechanical Impact Testing: A Statistical Measurement

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Herald, Stephen D.; Davis, S. Eddie

    2005-01-01

    In the decades since the 1950s, when NASA first developed mechanical impact testing of materials, researchers have continued efforts to gain a better understanding of the chemical, mechanical, and thermodynamic nature of the phenomenon. The impact mechanism is a real combustion ignition mechanism that needs understanding in the design of an oxygen system. The use of test data from this test method has been questioned due to lack of a clear method of application of the data and variability found between tests, material batches, and facilities. This effort explores a large database that has accumulated over a number of years and explores its overall nature. Moreover, testing was performed to determine the statistical nature of the test procedure to help establish sample size guidelines for material characterization. The current method of determining a pass/fail criterion based on either light emission or sound report or material charring is questioned.

  7. Modelling the impact testing of prescription lenses.

    PubMed

    McAuliffe, P J; Truss, R W; Pittolo, M

    1997-04-01

    Lenses are tested in an impact test in which a steel ball is dropped from a height onto the centre of the lens. This causes the lens to deform until the stress in the lens reaches a point at which fracture occurs. A survey of the literature was carried out and analytical models of the load/deflection and of the deflection/stress relationships were selected. A mathematical model of the impact test on lenses was developed. This model consisted of calculating the load-deflection relationship of a lens loaded at a central point, combined with calculating the deflection at which fracture occurred. From this model the impact energy required to deform a lens to fracture was obtained. This was held to be equal to the minimum kinetic energy of an impactor, less losses, that would be needed to cause lens fracture. As the losses are small, the calculated energy was used as an estimate of the impact strength of the lens. These values were then compared to those established by experiment. The impact energies predicted by the model were a close approximation of the experimental results for the lenses tested.

  8. New impact sensitivity test of liquid explosives

    NASA Astrophysics Data System (ADS)

    Tiutiaev, Andrei; Trebunskih, Valeri

    The sensitivity of liquid explosive in the presence of gas bubbles increases many times as compared with the liquid without gas bubbles. Local hot spot in this case formed as a result of compression and heating of the gas inside the bubbles. If we consider that in the liquid as a result of convection, wave motion, shock, etc. gas bubbles are easily generated, the need to develop a method for determining sensitivity of liquid explosives to impact and a detailed study of the ignition explosives with bubbles is obvious. On a mathematical model of a single steam bubbles in the fluid theoretically considered the process of initiating explosive liquid systems to impact. For the experimental investigation, the well-known K-44 -II with the metal cap were used. Instead of the metal cap in the standard method in this paper there was polyurethane foam cylindrical container with LHE, which is easily deforms by impact. A large number of tests with different liquid explosives were made. It was found that the test LHE to impact with polyurethane foam to a large extent reflect the real mechanical sensitivity due to the small loss of impact energy on the deformation of the metal cap, as well as the best differentiation LHE sensitivity due to the higher resolution method . Results obtained in the samara state technical university.

  9. Impact sensitivity test of liquid explosives

    NASA Astrophysics Data System (ADS)

    Tiutiaev, Andrei; Trebunskih, Valeri; Dolzhikov, Andrei; Zvereva, Irina

    2015-06-01

    The sensitivity of liquid explosive in the presence of gas bubbles increases many times as compared with the liquid without gas bubbles. If we consider that in the liquid as a result of convection, wave motion, shock, etc. gas bubbles are easily generated, the need to develop a method for determining sensitivity of liquid explosives to impact and a detailed study of the ignition explosives with bubbles is obvious. On a mathematical model of a single steam bubbles in the fluid theoretically considered the process of initiating explosive liquid systems to impact. For the experimental investigation, the well-known K-44 -II and the so-called appliance No. 1 were used. Instead of the metal cap in the standard method in this paper there was polyurethane foam cylindrical container with LHE, which is easily deforms by impact. A large number of tests with different liquid explosives were made. It was found that the test LHE to impact in appliance No. 1 with polyurethane foam to a large extent reflect the real mechanical sensitivity due to the small loss of impact energy on the deformation of the metal cap, as well as the best differentiation LHE sensitivity due to the higher resolution method .

  10. Apollo command module land impact tests

    NASA Technical Reports Server (NTRS)

    Mccullough, J. E.; Lands, J. F., Jr.

    1972-01-01

    Full-scale-model and actual spacecraft were impact tested to define the emergency land-landing capability of the Apollo command module. Structural accelerations and strains were recorded on analog instrumentation, and a summary to these data is included. The landing kinematics were obtained from high-speed photography. Photographs of the structural damage caused during the tests are included. Even though extensive damage can be expected, the crew will receive nothing more than minor injuries during the majority of the probable landing conditions.

  11. Factors affecting miniature Izod impact strength of tungsten-fiber-metal-matrix

    NASA Technical Reports Server (NTRS)

    Winsa, E. A.; Petrasek, D. W.

    1973-01-01

    The miniature Izod and Charpy impact strengths of copper, copper-nickel, and nickel-base superalloy uniaxially reinforced with continuous tungsten fibers were studied. In most cases, impact strength was increased by increasing fiber or matrix toughness, decreasing fibermatrix reaction, increasing test temperature, hot working, or heat treating. Notch sensitivity was reduced by increasing fiber content or matrix toughness. An equation relating impact strength to fiber and matrix properties and fiber content was developed. Program results imply that tungsten alloy-fiber/superalloy matrix composites can be made with adequate impact resistance for turbine blade or vane applications.

  12. The GISS sounding temperature impact test

    NASA Technical Reports Server (NTRS)

    Halem, M.; Ghil, M.; Atlas, R.; Susskind, J.; Quirk, W. J.

    1978-01-01

    The impact of DST 5 and DST 6 satellite sounding data on mid-range forecasting was studied. The GISS temperature sounding technique, the GISS time-continuous four-dimensional assimilation procedure based on optimal statistical analysis, the GISS forecast model, and the verification techniques developed, including impact on local precipitation forecasts are described. It is found that the impact of sounding data was substantial and beneficial for the winter test period, Jan. 29 - Feb. 21. 1976. Forecasts started from initial state obtained with the aid of satellite data showed a mean improvement of about 4 points in the 48 and 772 hours Sub 1 scores as verified over North America and Europe. This corresponds to an 8 to 12 hour forecast improvement in the forecast range at 48 hours. An automated local precipitation forecast model applied to 128 cities in the United States showed on an average 15% improvement when satellite data was used for numerical forecasts. The improvement was 75% in the midwest.

  13. Small punch test evaluation of intergranular embrittlement of an alloy steel

    SciTech Connect

    Baik, J.M.; Buck, O.; Kameda, J.

    1983-12-01

    The ductile-brittle transition temperature in steel is commonly determined using Charpy V-notch impact specimens as specified by ASTM E23-81. In some specific cases, however, the use of this standardized test specimen may be impractical, if not impossible. For instance, it is well known that ferritic steels show a substantial degradation of the mechanical properties after long time exposure to an irradiation environment. Because of the increase in strength and the reduction in ductility due to neutron irradiation, the Charpy V-notch transition temperature is raised causing concern from a safety point of view. To study these radiation effects, a test specimen much smaller than the standard Charpy V-notch specimen would be extremely desirable for two reasons. First, to study neutron damage small specimens take less space within a reactor. Secondly, the damage achieved in simulation experiments, such as proton or electron accelerators, is limited to small penetration depths. Several efforts on the development of such a small test specimen, similar to that used to determine the ductility of sheet metal, as recommended by ASTM E643-78, have been described in the literature. The paper reports on correlations between small punch (SP) and Charpy V-notch (CVN) test results obtained on temper-embrittled NiCr steel. The ductile-brittle transition temperature (DBTT) with intergranular embrittlement being induced by grain boundary segregation of specific impurities was determined. The relation between test results discussed in terms of the micromechanisms of intergranular cracking. It is suggested that in radiation embrittlement investigations similar correlations may be obtained.

  14. Elemental Water Impact Test: Phase 1 20-Inch Hemisphere

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2015-01-01

    Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 1 of the EWIT series featured water impact tests of a 20-inch hemisphere dropped from heights of 5 feet and 10 feet. The hemisphere was outfitted with an accelerometer and three pressure gages. The focus of this report is the correlation of analytical models against test data.

  15. Impact resistance of fiber composites - Energy-absorbing mechanisms and environmental effects

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Energy absorbing mechanisms were identified by several approaches. The energy absorbing mechanisms considered are those in unidirectional composite beams subjected to impact. The approaches used include: mechanic models, statistical models, transient finite element analysis, and simple beam theory. Predicted results are correlated with experimental data from Charpy impact tests. The environmental effects on impact resistance are evaluated. Working definitions for energy absorbing and energy releasing mechanisms are proposed and a dynamic fracture progression is outlined. Possible generalizations to angle-plied laminates are described.

  16. Impact resistance of fiber composites: Energy absorbing mechanisms and environmental effects

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    Energy absorbing mechanisms were identified by several approaches. The energy absorbing mechanisms considered are those in unidirectional composite beams subjected to impact. The approaches used include: mechanic models, statistical models, transient finite element analysis, and simple beam theory. Predicted results are correlated with experimental data from Charpy impact tests. The environmental effects on impact resistance are evaluated. Working definitions for energy absorbing and energy releasing mechanisms are proposed and a dynamic fracture progression is outlined. Possible generalizations to angle-plied laminates are described.

  17. Genetic Testing for Breast Cancer: Psychological and Social Impact

    MedlinePlus

    Genetic testing for breast cancer: Psychological and social impact Genetic testing to estimate breast and ovarian cancer risk ... By Mayo Clinic Staff Thinking about getting a genetic test to find out if you have a ...

  18. Low-temperature irradiation effects on tensile and Charpy properties of low-activation ferritic steels

    NASA Astrophysics Data System (ADS)

    Shiba, Kiyoyuki; Hishinuma, Akimichi

    2000-12-01

    Tensile and Charpy properties of low-activation ferritic steel, F82H irradiated up to 0.8 dpa at low temperature below 300°C were investigated. The helium effect on these properties was also investigated using the boron isotope doping method. Neutron irradiation increased yield stress accompanied with ductility loss, and it also shifted the ductile-to-brittle transition temperature (DBTT) from -50°C to 0°C. Boron-doped F82H showed larger degradation in DBTT and ductility than boron-free F82H, while they had the same yield stress before and after irradiation.

  19. Galileo battery testing and the impact of test automation

    NASA Technical Reports Server (NTRS)

    Pertuch, W. T.; Dils, C. T.

    1985-01-01

    Test complexity, changes of test specifications, and the demand for tight control of tests led to the development of automated testing used for Galileo and other projects. The use of standardized interfacing, i.e., IEEE-488, with desktop computers and test instruments, resulted in greater reliability, repeatability, and accuracy of both control and data reporting. Increased flexibility of test programming has reduced costs by permitting a wide spectrum of test requirements at one station rather than many stations.

  20. Instrumented impact testing at high velocities

    SciTech Connect

    Delfosse, D.; Pageau, G.; Bennett, R.; Poursartip, A. Defence Research Establishment Valcartier, Courcelette )

    1993-01-01

    Impact loading of carbon fiber-reinforced plastic (CFRP) aircraft parts is a major concern. Birds or hailstones striking an aircraft generally have a low mass and a high velocity, whereas typically instrumented impact experiments are performed with a high mass and a low velocity. Our aim has been to build an instrumented impact facility with a low-mass projectile capable of simulating these impact events, since there is evidence that a low-velocity impact will not always result in the same amount or even type of damage as a high-velocity impact. This paper provides a detailed description of the instrumented low-mass impact facility at The University of British Columbia (UBC). A gas gun is used to accelerate the instrumented projectile to impact velocities as high as 50 m/s, corresponding to an energy level of 350 J. The contact force during the impact event is measured by an incorporated load cell. The necessary mathematical operations to determine the real load-displacement curves are outlined, and the results of some impact events at different velocities are shown. 23 refs.

  1. Micrometeorite Impact Test of Flex Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.; Gardiner, G.

    2016-01-01

    Spacecraft with solar arrays operate throughout the near earth environment and are increasingly planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeorite impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. The Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeorite impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at NASA MSFC's Microlight Gas Gun Facility. The SSL-provided coupons consist of three strings, each string with two solar cells in series. Five impacts will be induced at various locations on a powered test coupon under different string voltage (0 volts - 150 volts) and string current (1.1 amperes - 1.65 amperes) conditions. The maximum specified test voltage and current represent margins of 1.5 times for both voltage and current. The test parameters are chosen to demonstrate new array design robustness to any ESD event caused by plasma plumes resulting from a simulated micrometeorite impact. A second unpowered coupon will undergo two impacts: one impact on the front side and one impact on the back side. Following the impact testing, the second coupon will be exposed to a thermal cycle test to determine possible damage propagation and further electrical degradation due to thermally-induced stress. The setup, checkout, and results from the impact testing are discussed. The challenges for impact testing include precise coupon alignment to control impact location; pressure management during the impact process; and measurement of the true transient electrical response during impact on the powered coupon. Results from pre- and post-test visual and electrical functional testing are also discussed.

  2. Application of laser, holographic, nondestructive testing by impact loading.

    PubMed

    Wang, J; Grant, I

    1995-07-01

    A description of research on holographic, nondestructive testing (HNDT) with impact loading is presented to demonstrate the technique as a practical HNDT method. The advantages of impact, or impulse, loading coupled with pulsed-laser illumination for HNDT away from the laboratory are discussed. The effect of the loading position, exposure timing, and prestressing on test results is discussed in detail. Experimental verification of the appropriateness of pulsed-laser HNDT in the testing of honeycomb materials by using impact loading is discussed.

  3. Advanced Crew Escape Suits (ACES): Particle Impact Test

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    NASA Johnson Space Center (JSC) requested NASA JSC White Sands Test Facility to assist in determining the effects of impaired anodization on aluminum parts in advanced crew escape suits (ACES). Initial investigation indicated poor anodization could lead to an increased risk of particle impact ignition, and a lack of data was prevalent for particle impact of bare (unanodized) aluminum; therefore, particle impact tests were performed. A total of 179 subsonic and 60 supersonic tests were performed with no ignition of the aluminum targets. Based on the resulting test data, WSTF found no increased particle impact hazard was present in the ACES equipment.

  4. Orion MPCV Water Landing Test at Hydro Impact Basin

    NASA Video Gallery

    This is the third Orion Multi-Purpose Crew Vehicle (MPCV) water landing test conducted at the Hydro Impact Basin at NASA Langley Research Center. This test represented the worst-case scenario for l...

  5. Negative Impacts of High-Stakes Testing

    ERIC Educational Resources Information Center

    Minarechová, Michaela

    2012-01-01

    High-stakes testing is not a new phenomenon in education. It has become part of the education system in many countries. These tests affect the school systems, teachers, students, politicians and parents, whether that is in a positive or negative sense. High-stakes testing is associated with concepts such as a school's accountability, funding and…

  6. Particle impact tests. [simulation of micrometeoroid damage to orbiter surface

    NASA Technical Reports Server (NTRS)

    Komatsu, G. K.

    1978-01-01

    Particle impact tests were performed on three types of orbiter surface with a micrometeoroid facility. The test equipment electrostatically accelerated micron sized particles to high velocities simulating micrometeoroid impacts. Test particles were titanium diboride with typical velocities in the range 1 to 2.3 km x sec/1 and equivalent particle diameters in the range 4 to 16 microns. Impact angles to the material surface were 90, 60 and 30 degrees. The particle impact sites were located on the sample surfaces and craters were photographed with a magnification of 400X.

  7. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  8. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  9. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  10. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  11. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  12. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  13. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  14. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  15. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  16. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  17. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Marking the impact test line. 1203.11 Section 1203.11 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior...

  18. Preparation of calibrated test packages for particle impact noise detection

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A standard calibration method for any particle impact noise detection (PIND) test system used to detect loose particles responsible for failures in hybrid circuits was developed along with a procedure for preparing PIND standard test devices. Hybrid packages were seeded with a single gold ball, hermetically sealed, leak tested, and PIND tested. Conclusions are presented.

  19. The Impact of EFL Testing on EFL Education in Korea

    ERIC Educational Resources Information Center

    Choi, Inn-Chull

    2008-01-01

    The present study provides an overview of the impact of standardized EFL tests on EFL education in Korea. To achieve this goal, the paper (1) presents the status quo of EFL testing in the Korean context, (2) explores the nature of the EFL tests prevalent in the EFL testing market, and (3) investigates the overwhelming washback effects of EFL tests…

  20. Impact Testing for Materials Science at NASA - MSFC

    NASA Technical Reports Server (NTRS)

    Sikapizye, Mitch

    2010-01-01

    The Impact Testing Facility (ITF) at NASA - Marshall Space Flight Center is host to different types of guns used to study the effects of high velocity impacts. The testing facility has been and continues to be utilized for all NASA missions where impact testing is essential. The Facility has also performed tests for the Department of Defense, other corporations, as well as universities across the nation. Current capabilities provided by Marshall include ballistic guns, light gas guns, exploding wire gun, and the Hydrometeor Impact Gun. A new plasma gun has also been developed which would be able to propel particles at velocities of 20km/s. This report includes some of the guns used for impact testing at NASA Marshall and their capabilities.

  1. Subtask 12F4: Effects of neutron irradiation on the impact properties and fracture behavior of vanadium-base alloys

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1995-03-01

    Up-to-date results on the effects of neutron irradiation on the impact properties and fracture behavior of V, V-Ti, V-Cr-Ti and V-Ti-Si alloys are presented in this paper, with an emphasis on the behavior of the U.S. reference alloys V-4Cr-4Ti containing 500-1000 wppm Si. Database on impact energy and cluctile-brittle transition temperature (DBTT) has been established from Charpy impact tests of one-third-size specimens irradiated at 420{degrees}C-600{degrees}C up to {approx}50 dpa in lithium environment in fast fission reactors. To supplement the Charpy impact tests fracture behavior was also characterized by quantitative SEM fractography on miniature tensile and disk specimens that were irradiated to similar conditions and fractured at -196{degrees}C to 200{degrees}C by multiple bending. For similar irradiation conditions irradiation-induced increase in DBTT was influenced most significantly by Cr content, indicating that irradiation-induced clustering of Cr atoms takes place in high-Cr (Cr {ge} 7 wt.%) alloys. When combined contents of Cr and Ti were {le}10 wt.%, effects of neutron irradiation on impact properties and fracture behavior were negligible. For example, from the Charpy-impact and multiple-bend tests there was no indication of irradiation-induced embrittlement for V-5Ti, V-3Ti-1Si and the U.S. reference alloy V-4Cr-4Ti after irradiation to {approx}34 dpa at 420{degrees}C to 600{degrees}C, and only ductile fracture was observed for temperatures as low as -196{degrees}C. 14 refs., 8 figs., 1 tab.

  2. Low power arcjet test facility impacts

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Lichon, Paul J.

    1992-01-01

    Performance characterization of a flight-type 1.4 kW arcjet system were conducted at the Rocket Research Company (RRC) in Redmond, WA, and at the NASA LeRC in Cleveland, OH. The objectives of these tests were as follows: to compare low-power arcjet performance at two different test facilities; to compare arcjet performance obtained with a 2:1 mixture of gaseous hydrogen and nitrogen and hydrazine; and to quantify the effects of test cell pressure on thruster operating characteristics. Performance and thruster temperature distributions were measured at thruster input power levels and propellant mass flow rates ranging from 1274 to 1370 W and from 3.2 x 10(exp -5) to 5.1 x 10(exp -5) kg/s, respectively. Specific impulses measured at the two facilities, at comparable test cell pressures, using gaseous hydrogen-nitrogen propellant mixtures agreed to within 1 percent over the range of operating conditions tested. The specific impulses measured using hydrazine propellant were higher than that for the cold hydrogen-nitrogen mixtures. Agreement between by hydrazine and gas mixture data was good, however, when the differences in propellant enthalpies at the thruster inlet were considered. Specific impulse showed a strong dependence on test facility pressure, and was 3 to 4 percent higher below 0.1 Pa than for test cell pressures above 5 Pa.

  3. Micrometeorite Impact Test of Flex Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.; Gardiner, G.

    2016-01-01

    Spacecraft with solar arrays operate throughout the near earth environment and are planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeoroid impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. NASA Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeoroid impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at MSFC's Micro Light Gas Gun Facility with SSL-provided coupons. Multiple impacts were induced at various locations on a powered test coupon under different string voltage (0V-150V) and string current (1.1A - 1.65A) conditions. The setup, checkout, and results from the impact testing are discussed.

  4. Impact of uncertainty on modeling and testing

    NASA Technical Reports Server (NTRS)

    Coleman, Hugh W.; Brown, Kendall K.

    1995-01-01

    A thorough understanding of the uncertainties associated with the modeling and testing of the Space Shuttle Main Engine (SSME) Engine will greatly aid decisions concerning hardware performance and future development efforts. This report will describe the determination of the uncertainties in the modeling and testing of the Space Shuttle Main Engine test program at the Technology Test Bed facility at Marshall Space Flight Center. Section 2 will present a summary of the uncertainty analysis methodology used and discuss the specific applications to the TTB SSME test program. Section 3 will discuss the application of the uncertainty analysis to the test program and the results obtained. Section 4 presents the results of the analysis of the SSME modeling effort from an uncertainty analysis point of view. The appendices at the end of the report contain a significant amount of information relative to the analysis, including discussions of venturi flowmeter data reduction and uncertainty propagation, bias uncertainty documentations, technical papers published, the computer code generated to determine the venturi uncertainties, and the venturi data and results used in the analysis.

  5. Assessing Individual-Level Impact of Interruptions during Online Testing

    ERIC Educational Resources Information Center

    Sinharay, Sandip; Wan, Ping; Choi, Seung W.; Kim, Dong-In

    2015-01-01

    With an increase in the number of online tests, the number of interruptions during testing due to unexpected technical issues seems to be on the rise. For example, interruptions occurred during several recent state tests. When interruptions occur, it is important to determine the extent of their impact on the examinees' scores. Researchers such as…

  6. Determining the Overall Impact of Interruptions during Online Testing

    ERIC Educational Resources Information Center

    Sinharay, Sandip; Wan, Ping; Whitaker, Mike; Kim, Dong-In; Zhang, Litong; Choi, Seung W.

    2014-01-01

    With an increase in the number of online tests, interruptions during testing due to unexpected technical issues seem unavoidable. For example, interruptions occurred during several recent state tests. When interruptions occur, it is important to determine the extent of their impact on the examinees' scores. There is a lack of research on this…

  7. The effect of heat treatment on the hardness and impact properties of medium carbon steel

    NASA Astrophysics Data System (ADS)

    Mazni Ismail, Noor; Khatif, Nurul Aida Amir; Aliff Kamil Awang Kecik, Mohamad; Hanafiah Shaharudin, Mohd Ali

    2016-02-01

    This paper covers the effect of heat treatment on the mechanical properties of medium carbon steel. The main objective of this project is to investigate the hardness and impact properties of medium carbon steel treated at different heat treatment processes. Three types of heat treatment were performed in this project which are annealing, quenching and tempering. During annealing process, the specimens were heated at 900°C and soaked for 1 hour in the furnace. The specimens were then quenched in a medium of water and open air, respectively. The treatment was followed by tempering processes which were done at 300°C, 450°C, and 600°C with a soaking time of 2 hours for each temperature. After the heat treatment process completed, Rockwell hardness test and Charpy impact test were performed. The results collected from the Rockwell hardness test and Charpy impact test on the samples after quenching and tempering were compared and analysed. The fractured surfaces of the samples were also been examined by using Scanning Electron Microscope. It was observed that different heat treatment processes gave different hardness value and impact property to the steel. The specimen with the highest hardness was found in samples quenched in water. Besides, the microstructure obtained after tempering provided a good combination of mechanical properties due to the process reduce brittleness by increasing ductility and toughness.

  8. Transient analysis of an IVHM grapple impact test

    NASA Technical Reports Server (NTRS)

    Hill, R. G.

    1972-01-01

    A lumped mass model was used to represent the impact condition between a fuel duct and an IVHM in-vessel fuel handling machine. The nonlinear effects of a Bellville spring and the free fall impact of the fuel duct on the IVHM were included. The purpose of the tests was to determine the loads on the fuel duct due to the impact. A comparison between experimental and theoretical results is presented.

  9. LLNL small-scale drop-hammer impact sensitivity test

    SciTech Connect

    Simpson, L.R.; Foltz, M.F.

    1995-01-01

    Small-scale safety testing of explosives and other energetic materials is done to determine their sensitivity to various stimuli including friction, static spark, and impact. This testing is typically done to discover potential handling problems for either newly synthesized materials of unknown behavior or materials that have been stored for long periods of time. This report describes the existing ``ERL Type 12 Drop Weight Impact Sensitivity Apparatus``, or ``Drop Hammer Machine``, and the methods used to determine the impact sensitivity of energetic materials, Also discussed are changes made to both the machine and methods since the inception of impact sensitivity testing at LLNL in 1956. The accumulated data for the materials tested in not listed here, the exception being the discussion of those specific materials (primary calibrants: PETN, RDX, Comp-B3,and TNT; secondary calibrants: K-6, RX-26-AF, and TATB) used to calibrate the machine.

  10. Shallow seismic test at Marquez impact structure

    NASA Astrophysics Data System (ADS)

    Herrick, R. R.; Sharpton, V. L.

    1997-03-01

    Marquez Dome is the filled and eroded remnant of an about 15-km diameter, 58 Ma impact into unconsolidated sediments in Southeast Texas. The 3-km diameter central peak outcrops as Cretaceous marls and shales at the surface and is flanked by pre- and postimpact tertiary sands and clays. Petroleum exploration data for Marquez include over 160 km of reflection seismic data criss-crossing the site and numerous logged wells. These data have been used to roughly define the extent of the central peak from a zone of no continuous reflectors and the rim from low-angle, modest offset normal faults. A minimum group interval of 33 m and near offset of 100 m cause the industrial seismic data to be of low quality in the upper 250 ms, and consequently these lines do not image the flanks of the central peak and the shallow rim faults. We conducted a shallow seismic investigation to see if engineering seismic equipment could be used to image the flanks of the central peak and fill in the missing 250 ms in the industrial data.

  11. Impact Testing of Orbiter Thermal Protection System Materials

    NASA Technical Reports Server (NTRS)

    Kerr, Justin

    2006-01-01

    This viewgraph presentation reviews the impact testing of the materials used in designing the shuttle orbiter thermal protection system (TPS). Pursuant to the Columbia Accident Investigation Board recommendations a testing program of the TPS system was instituted. This involved using various types of impactors in different sizes shot from various sizes and strengths guns to impact the TPS tiles and the Leading Edge Structural Subsystem (LESS). The observed damage is shown, and the resultant lessons learned are reviewed.

  12. Development of impact resistant boron/aluminum composites for turbojet engine fan blades

    NASA Technical Reports Server (NTRS)

    Melnyk, P.; Toth, I. J.

    1975-01-01

    Composite fabrication was performed by vacuum press diffusion bonding by both the foil-filament array and preconsolidated monotape methods. The effect of matrix material, fiber diameter, matrix enhancement, fiber volume reinforcement, test temperature, angle-plying, notch, impact orientation, processing variables and fabrication methods on tensile strength and Charpy impact resistance are evaluated. Root attachment concepts, were evaluated by room and elevated temperature tensile testing, as well as by pendulum-Izod and ballistic impact testing. Composite resistance to foreign object damage was also evaluated by ballistic impacting of panels using projectiles of gelatin, RTV rubber and steel at various velocities, and impingement angles. A significant improvement in the pendulum impact resistance of B-Al composites was achieved.

  13. Impact on HIV test providers of giving a positive test result.

    PubMed

    Myers, Ted; Worthington, Catherine; Aguinaldo, Jeffrey P; Haubrich, Dennis J; Ryder, Karen; Rawson, Brian

    2007-09-01

    The provision of a positive HIV antibody test result and the direction and support given to the test recipient are critical components of care and prevention. There has been little research that describes what happens in such interactions between recipient and provider. The impact on the test provider of delivering the HIV test result is an important issue to consider. The discomfort experienced by some health providers in giving a positive test result may have adverse effects on the client interaction or may carry over into subsequent client interactions. Utilizing a thematic analysis on interview data from 24 HIV test providers, we describe the impact of delivering a positive test result on HIV test providers, identify the factors that influence this impact, and describe strategies used to manage the impact. As with other health care professionals communicating "bad news,"HIV test providers experience a variety of impacts. While a small number of providers indicated little or no impact of delivering the HIV positive test result because the diagnosis is ''not the end of the world,'' most indicated it was difficult as it was anticipated that the test recipient would (or did) find the news distressing. Several coping strategies were identified.

  14. XDT in HTPB propellant from steel flyer plate impact tests

    NASA Astrophysics Data System (ADS)

    Tanaka, Katsumi; Noda, Keiichiro; Hyodo, Yukio; Nakamura, Hiroyuki; Kosaka, Katsuaki; Nakayama, Takashi; Katayama, Masahide; Takeba, Atsushi

    2000-04-01

    Several experiments simulating ground impact explosion following the command destruction of a launch vehicle have been performed using HTPB propellant samples of mass 460 to 940 kg impacted by a steel flyer plate. Impact velocities were varied from 135 m/s to 170 m/s. Strong explosions were observed at impact velocities higher than 150 m/s for tests of solid rocket propellant weighting 460 kg. The XDT (Unknown to Detonation Transition) is studied using a bulk failure reaction model including strain rate effect. Computational results are compared with observed blast waves for various impact velocities. The present model has been successfully applied to 22 inch Critical Diameter tests for SRMU HTPB propellant.

  15. Impact Testing and Simulation of Composite Airframe Structures

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Littell, Justin D.; Horta, Lucas G.; Annett, Martin S.; Fasanella, Edwin L.; Seal, Michael D., II

    2014-01-01

    Dynamic tests were performed at NASA Langley Research Center on composite airframe structural components of increasing complexity to evaluate their energy absorption behavior when subjected to impact loading. A second objective was to assess the capabilities of predicting the dynamic response of composite airframe structures, including damage initiation and progression, using a state-of-the-art nonlinear, explicit transient dynamic finite element code, LS-DYNA. The test specimens were extracted from a previously tested composite prototype fuselage section developed and manufactured by Sikorsky Aircraft Corporation under the US Army's Survivable Affordable Repairable Airframe Program (SARAP). Laminate characterization testing was conducted in tension and compression. In addition, dynamic impact tests were performed on several components, including I-beams, T-sections, and cruciform sections. Finally, tests were conducted on two full-scale components including a subfloor section and a framed fuselage section. These tests included a modal vibration and longitudinal impact test of the subfloor section and a quasi-static, modal vibration, and vertical drop test of the framed fuselage section. Most of the test articles were manufactured of graphite unidirectional tape composite with a thermoplastic resin system. However, the framed fuselage section was constructed primarily of a plain weave graphite fabric material with a thermoset resin system. Test data were collected from instrumentation such as accelerometers and strain gages and from full-field photogrammetry.

  16. Marshall Space Flight Center's Impact Testing Facility Capabilities

    NASA Technical Reports Server (NTRS)

    Finchum, Andy; Hubbs, Whitney; Evans, Steve

    2008-01-01

    Marshall Space Flight Center s (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960s, then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California. The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility s unique capabilities were deemed a "National Asset" by the DoD. The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas guns, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

  17. Impact Testing of Stainless Steel Material at Cold Temperatures

    SciTech Connect

    Spencer D. Snow; D. Keith Morton; Robert K. Blandford

    2008-07-01

    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 are not well documented. However, a previous paper [1] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens at room and elevated temperatures. The goal of the work presented herein is to add recently completed impact tensile testing results at -20 degrees F conditions for dual-marked 304/304L and 316/316L stainless steel material specimens (hereafter referred to as 304L and 316L, respectively). Recently completed welded material impact testing at -20 degrees F, room, 300 degrees F, and 600 degrees F is also reported. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, the impact tests achieved strain rates in the 4 to 40 per second range, depending upon the material temperature. Elevated true stress-strain curves for these materials reflecting varying strain rates and temperatures are presented herein.

  18. 76 FR 31860 - Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... National Highway Traffic Safety Administration 49 CFR Part 572 RIN 2127-AK64 Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety... rule published on June 16, 2008, concerning a 50th percentile adult male side crash test dummy...

  19. 75 FR 5931 - Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-05

    ... National Highway Traffic Safety Administration 49 CFR Part 572 RIN 2127-AK64 Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety... final rule that had adopted specifications and qualification requirements for a new crash test...

  20. Properties of precipitation hardened steel irradiated at 323 K in the Japan materials testing reactor

    NASA Astrophysics Data System (ADS)

    Niimi, M.; Matsui, Y.; Jitsukawa, S.; Hoshiya, T.; Tsukada, T.; Ohmi, M.; Mimura, H.; Ooka, N.; Hide, K.

    A precipitation hardening type 630 stainless steel was irradiated in the Japan Materials Testing Reactor (JMTR) in contact with the reactor primary coolant. The temperature of the irradiated specimens was about 330 K. The fast neutron ( E > 1 MeV) fluence for the specimens ranged from 10 24 to 10 26 m -2. Tension tests and fracture toughness tests were carried out at room temperature, while Charpy impact tests were done at temperatures of 273-453 K. Tensile strength data showed a peak of 1600 MPa at around 7 × 10 24 m -2, then gradually decreased to about 1500 MPa at 1.2 × 10 26 m -2. The elongation decreased with irradiation from 12% for unirradiated material to 6% at 1.2 × 10 26 m -2. The fractography after the tension test revealed that the fracture was ductile. Fracture toughness decreased to about a half of the value for unirradiated material with irradiation. The cleavage fracture was dominant on the fractured surface. Charpy impact tests showed an increase of ductile-brittle transition temperature (DBTT) by 60 K with irradiation.

  1. Impact Testing of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2001-01-01

    Before composite materials can be considered for use in the fan case of a commercial jet engine, the performance of a composite structure under blade-out loads needs to be demonstrated. The objective of this program is to develop an efficient test and analysis method for evaluating potential composite case concepts. Ballistic impact tests were performed on laminated glass/epoxy composites in order to identify potential failure modes and to provide data for analysis. Flat 7x7 in. panels were impacted with cylindrical titanium projectiles, and 15 in. diameter half-rings were impacted with wedge-shaped titanium projectiles. Composite failure involved local fiber fracture as well as tearing and delamination on a larger scale. A 36 in. diameter full-ring subcomponent was proposed for larger scale testing. Explicit, transient, finite element analyses were used to evaluate impact dynamics and subsequent global deformation for the proposed full-ring subcomponent test. Analyses on half-ring and quarter ring configurations indicated that less expensive smaller scale tests could be used to screen potential composite concepts when evaluation of local impact damage is the primary concern.

  2. Responses of side impact dummies in sled tests.

    PubMed

    Yoganandan, Narayan; Pintar, Frank A

    2005-05-01

    Sled tests were conducted at a velocity of 6.7 m/s using side impact dummies (SID, BioSID, ES-2, and WorldSIDp) and the resulting biomechanical responses were compared with responses from post mortem human subjects (PMHS). Initial impact conditions were with and without pelvic offset in combination with and without padding on the impacting wall. Impact forces, thoracic trauma index, chest compression, and viscous criteria were evaluated. The probability of injury was estimated and rates of deformation were computed for each body region. Dummy responses were not always similar in terms of trend and injury criteria when compared with PMHS tests under the same initial conditions. Response variations will be of value in improving the biofidelity characteristics of dummies for crashworthiness evaluations.

  3. The Impact of Personality and Test Conditions on Mathematical Test Performance

    ERIC Educational Resources Information Center

    Hayes, Heather; Embretson, Susan E.

    2013-01-01

    Online and on-demand tests are increasingly used in assessment. Although the main focus has been cheating and test security (e.g., Selwyn, 2008) the cross-setting equivalence of scores as a function of contrasting test conditions is also an issue that warrants attention. In this study, the impact of environmental and cognitive distractions, as…

  4. Comparison of high speed impact test of solder joints with board level drop test

    NASA Astrophysics Data System (ADS)

    Guruprasad, Pradosh

    Efforts have been made in this study to evaluate the characteristics of solder joint failure by using a new high speed impact tester. First, the dynamics and characteristics of the test vehicle in a board level drop test have been evaluated. A thorough understanding of the behavior of the test vehicle is examined by characterizing its response under different test profiles and board dimensions. This is done in an attempt to optimize the test procedure used to qualify electronic products subjected to high strain rate drop/shock environment. The effects of peak acceleration and change in velocity of the impact pulse on the reliability of the test vehicle have been studied. In situ strain measurements have been used to aid us in characterizing the board response under high strain rate loading conditions. Also finite element analysis has been used to better understand the board response under different loading conditions. Based on the experimental results and analysis, ways to improvise the drop test setup have been discussed. A more thorough understanding of the solder joint behavior is examined by characterizing the behavior with respect to varying impact profiles on a new pendulum fatigue and a high speed impact tester. This is done in an attempt to address solder joint failures in actual product that may be operating under high strain rate or shock environments and to reduce the actual test time needed for a board level drop test. Comparison between the high speed pendulum impact test and drop test was primarily made by evaluating the failure modes from these two tests. Energy absorbed by the solder in a single impact has been used to predict the reliability in a board level test.

  5. Marshall Space Flight Center's Impact Testing Facility Capabilities

    NASA Technical Reports Server (NTRS)

    Evans, Steve; Finchum, Andy; Hubbs, Whitney; Gray, Perry

    2008-01-01

    Marshall Space Flight Center's (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960s, then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California, The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility's unique capabilities were deemed a 'National Asset' by the DoD, The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Relocated test equipment was dated and in need of upgrade. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. Future ITF improvements will be focused on continued instrumentation and performance enhancements. These enhancements will allow further, more in-depth, characterization of rain drop demise characterization and evaluation of ice crystal impact. Performance enhancements also include increasing the upper velocity limit of the current environmental guns to allow direct environmental simulation for missile components. The current and proposed

  6. Marshall Space Flight Center's Impact Testing Facility Capabilities

    NASA Technical Reports Server (NTRS)

    Evans, Steve; Finchum, Andy; Hubbs, Whitney

    2008-01-01

    Marshall Space Flight Center's (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960% then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California. The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility's unique capabilities were deemed a "National Asset" by the DoD. The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Relocated test equipment was dated and in need of upgrade. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. Future ITF improvements will be focused on continued instrumentation and performance enhancements. These enhancements will allow further, more in-depth, characterization of rain drop demise characterization and evaluation of ice crystal impact. Performance enhancements also include increasing the upper velocity limit of the current environmental guns to allow direct environmental simulation for missile components. The current and proposed

  7. Neural Networks Analyze Data In Particle-Impact-Noise Tests

    NASA Technical Reports Server (NTRS)

    Scaglione, Lois J.

    1995-01-01

    Electronic neural networks and computers put to use in analyzing data acquired in particle-impact-noise-detection (PIND) tests of packaged electronic components. PIND tests detect loose particles in packages that cause failures during subsequent operation of packages in presence of accelerations or other effects - for example, loose electrically conductive particles that bounce into positions in which they cause short circuits. Interpretation of test data more objective and accurate. Preliminary results suggest use of neural networks result in significant improvement in quality and reliability and decrease in cost of PIND testing.

  8. Impact tests on rubber compression springs for airplane landing gears

    NASA Technical Reports Server (NTRS)

    Hohenemser, K

    1930-01-01

    The present report gives the results of tests which were made for the purpose of solving the problem of whether diagrams obtained from pressure tests could be conclusive for the determination of the safe impact coefficients. It is first established that the rubber rings adhere firmly to the compression surfaces during deformation. Suggestions are thus obtained for a constructive simplification of the rubber rings. The hysteresis phenomenon is ascribed to external and internal friction forces. A device for falling tests is then described with which the process of shock absorption with rubber rings was tested.

  9. Hypervelocity Impact Testing of Nickel Hydrogen Battery Cells

    NASA Technical Reports Server (NTRS)

    Frate, David T.; Nahra, Henry K.

    1996-01-01

    Nickel-Hydrogen (Ni/H2) battery cells have been used on several satellites and are planned for use on the International Space Station. In January 1992, the NASA Lewis Research Center (LeRC) conducted hypervelocity impact testing on Ni/H2 cells to characterize their failure modes. The cell's outer construction was a 24 mil-thick Inconel 718 pressure vessel. A sheet of 1.27 cm thick honeycomb was placed in front of the battery cells during testing to simulate the on-orbit box enclosure. Testing was conducted at the NASA White Sands Test Facility (WSTF). The hypervelocity gun used was a 7.6 mm (0.30 caliber) two-stage light gas gun. Test were performed at speeds of 3, 6, and 7 km/sec using aluminum 2017 spherical particles of either 4.8 or 6.4 mm diameter as the projectile. The battery cells were electrically charged to about 75 percent of capacity, then back-filled with hydrogen gas to 900 psi simulating the full charge condition. High speed film at 10,000 frames/sec was taken of the impacts. Impacts in the dome area (top) and the electrode area (middle) of the battery cells were investigated. Five tests on battery cells were performed. The results revealed that in all of the test conditions investigated, the battery cells simply vented their hydrogen gas and some electrolyte, but did not burst or generate any large debris fragments.

  10. Hypervelocity Impact Test Results for a Metallic Thermal Protection System

    NASA Technical Reports Server (NTRS)

    Karr, Katherine L.; Poteet, Carl C.; Blosser, Max L.

    2003-01-01

    Hypervelocity impact tests have been performed on specimens representing metallic thermal protection systems (TPS) developed at NASA Langley Research Center for use on next-generation reusable launch vehicles (RLV). The majority of the specimens tested consists of a foil gauge exterior honeycomb panel, composed of either Inconel 617 or Ti-6Al-4V, backed with 2.0 in. of fibrous insulation and a final Ti-6Al-4V foil layer. Other tested specimens include titanium multi-wall sandwich coupons as well as TPS using a second honeycomb sandwich in place of the foil backing. Hypervelocity impact tests were performed at the NASA Marshall Space Flight Center Orbital Debris Simulation Facility. An improved test fixture was designed and fabricated to hold specimens firmly in place during impact. Projectile diameter, honeycomb sandwich material, honeycomb sandwich facesheet thickness, and honeycomb core cell size were examined to determine the influence of TPS configuration on the level of protection provided to the substructure (crew, cabin, fuel tank, etc.) against micrometeoroid or orbit debris impacts. Pictures and descriptions of the damage to each specimen are included.

  11. Impact Testing of a Stirling Converter's Linear Alternator

    NASA Technical Reports Server (NTRS)

    Suarez, Vicente J.; Goodnight, Thomas W.; Hughes, William O.; Samorezov, Sergey

    2002-01-01

    The U.S. Department of Energy (DOE), in conjunction with the NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of this test was to identify dynamic structural characteristics of the Stirling Technology Demonstration Convertor (TDC). This paper addresses the test setup, procedure, and results of the impact testing conducted on the Stirling TDC in May 2001.

  12. Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2010-01-01

    The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests on full-scale and sub-scale Orion spacecraft mass simulators. Recently, a three-dimensional photogrammetry system was acquired to assist with the gathering of vehicle flight data before, throughout and after the impact. This data provides the basis for the post-test analysis and data reduction. Experimental setups for pendulum swing tests on vehicles having both forward and vertical velocities can extend to 50 x 50 x 50 foot cubes, while weather, vehicle geometry, and other constraints make each experimental setup unique to each test. This paper will discuss the specific calibration techniques for large fields of views, camera and lens selection, data processing, as well as best practice techniques learned from using the large field of view photogrammetry on a multitude of crash and landing test scenarios unique to the LandIR.

  13. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

    Reimus, M.A.H.; Hhinckley, J.E.

    1997-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of [sup 238]Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). The modular GPHS design was developed to address both survivability during launch abort and return from orbit. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

  14. Analysis-test correlation of airbag impact for Mars landing

    SciTech Connect

    Salama, M.; Davis, G.; Kuo, C.P.

    1994-12-31

    The NASA Mars Pathfinder mission is intended to demonstrate key low cost technologies for use in future science missions to Mars. Among these technologies is the landing system. Upon entering in Martian atmosphere at about 7000 m/sec., the spacecraft will deploy a series of breaking devices (parachute and solid rockets) to slow down its speed to less than 20 m/sec. as it impacts with the Martian ground. To cushion science instruments form the landing impact, an airbag system is inflated to surround the lander approximately five seconds before impact. After multiple bounces, the lander/airbags comes to rest, the airbags are deflated and retracted, and the lander opens up its petals to allow a microrover to begin exploration. Of interest here, is the final landing phase. Specifically, this paper will focus on the methodology used to simulate the nonlinear dynamics of lander/airbags landing impact, and how this simulation correlates with initial tests.

  15. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Marking the impact test line. 1203.11 Section 1203.11 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... the helmet on the appropriate headform as specified by the manufacturer's helmet positioning...

  16. Hypervelocity impact tests on Space Shuttle Orbiter thermal protection material

    NASA Technical Reports Server (NTRS)

    Humes, D. H.

    1977-01-01

    Hypervelocity impact tests were conducted to simulate the damage that meteoroids will produce in the Shuttle Orbiter leading edge structural subsystem material. The nature and extent of the damage is reported and the probability of encountering meteoroids with sufficient energy to produce such damage is discussed.

  17. Low velocity impact testing and nondestructive evaluation of transparent materials

    SciTech Connect

    Brennan, R. E.; Green, W. H.

    2011-06-23

    Advanced transparent materials are used in protective systems for enhancing the survivability of ground vehicles, air vehicles, and personnel in applications such as face shields, riot gear, and vehicle windows. Low velocity impact damage can limit visibility and compromise the structural integrity of a transparent system, increasing the likelihood of further damage or penetration from a high velocity impact strike. For this reason, it is critical to determine damage tolerance levels of transparent systems to indicate whether or not a component should be replaced. In this study, transparent laminate systems will be tested by comparing baseline conditions to experimentally controlled damage states. Destructive testing including air gun and sphere impact testing will be used to replicate low velocity impacts in the field. Characterization of the damaged state will include basic visual inspection as well as nondestructive techniques including cross-polarization, x-ray, and ultrasound. The combination of destructive testing and characterization of the resulting damage can help to establish a damage acceptance criterion for materials used in protective systems.

  18. Assessment of mechanical properties of the martensitic steel EUROFER97 by means of punch tests

    NASA Astrophysics Data System (ADS)

    Ruan, Y.; Spätig, P.; Victoria, M.

    2002-12-01

    The ball punch test technique was used to evaluate the conventional tensile and impact properties of the tempered martensitic steel EUROFER97 from room temperature down to liquid nitrogen temperature. The testing was carried out on unirradiated material only with small disks, 3 mm in diameter and 0.25 mm in thickness. For comparison, tensile tests were also performed over the same temperature range. Correlations between the load at the plastic bending initiation and the maximum load of the punch tests with the yield stress and the ultimate tensile stress of the tension tests could be established. The temperature dependence of the specific fracture energy of the punch test was used to define a ductile-brittle transition temperature (DBTT) and to correlate this with the DBTT measured from impact Charpy on KLST specimens. The results are compared with other available correlations done in the past on other ferritic steels.

  19. Toughness testing and high-temperature oxidation evaluations of advanced alloys for core internals

    SciTech Connect

    Tan, Lizhen; Pint, Bruce A.; Chen, Xiang

    2016-09-16

    Alloy X-750 was procured from Carpenter Technology and Bodycote in this year. An appropriate TMT was developed on Alloy 439 to obtain materials with refined grain size for property screening tests. Charpy V-notch impact tests were completed for the three ferritic steels Grade 92, Alloy 439, and 14YWT. Fracture toughness tests at elevated temperatures were completed for 14YWT. The tests will be completed for the other alloys in next fiscal year. Steam oxidation tests of the three ferritic steels, 316L, and Zr–2.5Nb have been completed. The steam tests of the Ni-based superalloys and the other austenitic stainless steels will be continued and finished in next fiscal year. Performance ranking in terms of steam oxidation resistance and impact/fracture toughness of the alloys will be deduced.

  20. Sloshing roof impact tests of a rectangular tank

    SciTech Connect

    Minowa, C.; Ogawa, N.; Harada, I.; Ma, D.C.

    1994-06-01

    Some tanks have been damaged at the roofs due to sloshing impact caused by strong earthquakes. It is, therefore, necessary to consider the impact force in the aseismic design code for tank roofs. However, there are few studies on the earthquake responses of storage and process tank roofs. As a first step to investigate the effects of sloshing impact a series of the shaking table tests of a rectangular tank have been conducted at the National Research Institute for Earth Science and Disaster Prevention (NIED). The results of these shaking table tests are presented in the paper. The test tank is rectangular in shape having dimensions of 5 m {times} 3 m {times} 2 m length {times} width {times} height). The tank was constructed of glass-fiber reinforced plastic panels. Every panel had a flange on four edges, and each panel was connected by bolts along the flange. The test tank was set on the NIED shaking table (15 m by 15 m). Two types of liquid were used, water and a viscous liquid (water mixed with polymeric powders). The roof impact pressures and other quantities were measured. During the tests using the 400 pi El-Centro excitation, the roof deformation sensor steel beam was damaged. The response of side walls with different rigidity were measured in the wall bulging tests. The measured vibrations within the panel plates were larger than those in the panel flanges. The viscous liquid of 100 cp had little influence on wall bulging responses. However, the viscous effects on sloshing responses were observed in the sloshing tests. Approximate analyses of rectangular tanks, considering the influence of static water pressure, are also presented in this paper.

  1. Sloshing roof impact tests of a rectangular tank

    NASA Astrophysics Data System (ADS)

    Minowa, Chikahiro; Ogawa, Nobuyuki; Harada, Iki; Ma, David C.

    Some tanks have been damaged at the roofs due to sloshing impact caused by strong earthquakes. It is, therefore, necessary to consider the impact force in the aseismic design code for tank roofs. However, there are few studies on the earthquake responses of storage and process tank roofs. As a first step to investigate the effects of sloshing impact a series of the shaking table tests of a rectangular tank have been conducted at the National Research Institute for Earth Science and Disaster Prevention (NIED). The results of these shaking table tests are presented in the paper. The test tank is rectangular in shape having dimensions of 5 m x 3 m x 2 m (length x width x height). The tank was constructed of glass-fiber reinforced plastic panels. Every panel had a flange on four edges, and each panel was connected by bolts along the flange. The test tank was set on the NIED shaking table (15 m by 15 m). Two types of liquid were used, water and a viscous liquid (water mixed with polymeric powders). The roof impact pressures and other quantities were measured. During the tests using the 400 pi El-Centro excitation, the roof deformation sensor steel beam was damaged. The response of side walls with different rigidity were measured in the wall bulging tests. The measured vibrations within the panel plates were larger than those in the panel flanges. The viscous liquid of 100 cp had little influence on wall bulging responses. However, the viscous effects on sloshing responses were observed in the sloshing tests. Approximate analyses of rectangular tanks, considering the influence of static water pressure, are also presented in this paper.

  2. West Valley Demonstration Project full-scale canister impact tests

    SciTech Connect

    Whittington, K.F.; Lutz, C.E.

    1995-12-31

    Five West Valley Nuclear Services (WVNS) high-level waste (HLW) canisters were impact tested during 1994 to demonstrate compliance with the drop test requirements of the Waste Acceptance Product Specifications. The specifications state that the canistered waste form must be able to survive a 7-m (23 ft) drop unbreached. The 10-gauge stainless steel canisters were approximately 85% filled with simulated vitrified waste and weighed about 2100 kg (4600 lb). Each canister was dropped vertically from a height of 7 m (23 ft) onto an essentially unyielding surface. The integrity of the canister was determined by the application and analysis of strain circles, dimensional measurements, and helium leak testing. The canisters were also visually inspected before and after the drop for physical damage. After the impact, very little deformation of the canisters was observed. The strain circles deformed in the axial direction less than 3% and up to 7% in the hoop direction. The canisters on average showed a slight diameter increase of approximately 2% (1 to 2 cm) in the area nearest to the bottom head. The diameter only increased an average of 0.8% (0.5 cm) at the 76-cm elevation. The canister height decreased by an average of 0.4% (1.2 cm). Helium leak testing of each weld showed either no detectable leaks or very slight leaks much less than the acceptance criteria of 10{sup {minus}4} atm cc/sec. Each of the canisters passed the ``straightness`` test in which the canisters were fit into an inspection sleeve, a straight cylinder with a 63.5-cm (25 in) diameter, after the impact. The results of the impact test verify that the canisters survived the 7-m drops unbreached. Therefore, these results demonstrate that the reference canister meets the drop test specification of the Waste Acceptance Product Specification.

  3. A drop tower for controlled impact testing of biological tissues.

    PubMed

    Burgin, Leanne V; Aspden, Richard M

    2007-05-01

    Impact damage, in particular to tissues such as articular cartilage, is a recognised source of morbidity. To understand better the clinical outcomes, it is important to know the mechanics of the damage sustained and the biological response of cells to rapidly applied forces and subsequent tissue disruption. An instrumented drop tower has been designed to enable controlled impact loads to be applied to small samples of biological materials. Impact severity can be controlled by using impactors of different masses and various drop heights. Force and deceleration at impact are recorded at 50,000 samples s(-1) by a force transducer under the sample and an accelerometer on the impactor. Repeatability was tested on rubber washers and coefficients of variation were found to be better than 8% for dynamic stiffness, 3.4% for stress and 4.3% for strain. Initial tests on isolated biopsies of articular cartilage showed that at an initial strain rate of 916 s(-1), the peak dynamic modulus of human femoral head cartilage was 59 MPa, and for a bovine biopsy the initial strain rate and corresponding peak dynamic modulus were 3380 s(-1) and 130 MPa, respectively. The equipment described is capable of applying an impact load to small biopsies of tissue with a defined energy and velocity and measuring deformation and load at high rates of loading.

  4. 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.

  5. Hydrodynamic impact analysis and testing of an unmanned aerial vehicle

    NASA Astrophysics Data System (ADS)

    Bird, Isabel

    Analysis and testing have been conducted to assess the feasibility of a small UAV that can be landed in the water and recovered for continued use. Water landings may be desirable in a number of situations, for example when testing UAVs outside of the territorial waters of the US to avoid violating FAA regulations. Water landings may also be desirable when conducting surveillance missions in marine environments. Although the goal in landing is to have the UAV lightly set down on the water, rough seas or gusty winds may result in a nose-in landing where the UAV essentially impacts the surface of the water. The tested UAV is a flying wing design constructed of expanded polypropylene foam wings with a hollowed out center-section for the avionics. Acceleration data was collected by means of LIS331 3-axis accelerometers positioned at five locations, including the wingtips. This allowed conclusions to be drawn with respect to the loads experienced on impact throughout the airframe. This data was also used to find loads corresponding to the maximum decelerations experienced during impact. These loads were input into a finite element analysis model of the wing spars to determine stress in the wing spars. Upon impact, the airframe experienced high-frequency oscillation. Surprisingly, peak accelerations at the wingtips were observed at up to 15g greater than corresponding accelerations at the center of the fuselage.

  6. Effect of aging on impact properties of ASTM A890 Grade 1C super duplex stainless steel

    SciTech Connect

    Martins, Marcelo Forti, Leonardo Rodrigues Nogueira

    2008-02-15

    Super duplex stainless steels in the solution annealed condition are thermodynamically metastable systems which, when exposed to heat, present a strong tendency to 'seek' the most favorable thermodynamic condition. The main purpose of this study was to characterize the microstructure of a super duplex stainless steel in the as cast and solution annealed conditions, and to determine the influence of aging heat treatments on its impact strength, based on Charpy impact tests applied to V-notched test specimens. The sigma phase was found to begin precipitating at heat treatment temperatures above 760 deg. C and to dissolve completely only above 1040 deg. C, with the highest peak concentration of this phase appearing at close to 850 deg. C. Heat treatments conducted at temperatures of 580 deg. C to 740 deg. C led to a reduction of the energy absorbed in the Charpy impact test in response to the precipitation of a particulate phase with particle sizes ranging from 0.5 {mu}m to 1.0 {mu}m, with a chromium and iron-rich chemical composition.

  7. Space Shuttle Main Engine Debris Testing Methodology and Impact Tolerances

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R.; Stephens, Walter

    2005-01-01

    In the wake of the Space Shuttle Columbia disaster every effort is being made to determine the susceptibility of Space Shuttle elements to debris impacts. Ice and frost debris is formed around the aft heat shield closure of the orbiter and liquid hydrogen feedlines. This debris has been observed to liberate upon lift-off of the shuttle and presents potentially dangerous conditions to the Space Shuttle Main Engine. This paper describes the testing done to determine the impact tolerance of the Space Shuttle Main Engine nozzle coolant tubes to ice strikes originating from the launch pad or other parts of the shuttle.

  8. Hypervelocity Impact Test Facility: A gun for hire

    NASA Technical Reports Server (NTRS)

    Johnson, Calvin R.; Rose, M. F.; Hill, D. C.; Best, S.; Chaloupka, T.; Crawford, G.; Crumpler, M.; Stephens, B.

    1994-01-01

    An affordable technique has been developed to duplicate the types of impacts observed on spacecraft, including the Shuttle, by use of a certified Hypervelocity Impact Facility (HIF) which propels particulates using capacitor driven electric gun techniques. The fully operational facility provides a flux of particles in the 10-100 micron diameter range with a velocity distribution covering the space debris and interplanetary dust particle environment. HIF measurements of particle size, composition, impact angle and velocity distribution indicate that such parameters can be controlled in a specified, tailored test designed for or by the user. Unique diagnostics enable researchers to fully describe the impact for evaluating the 'targets' under full power or load. Users regularly evaluate space hardware, including solar cells, coatings, and materials, exposing selected portions of space-qualified items to a wide range of impact events and environmental conditions. Benefits include corroboration of data obtained from impact events, flight simulation of designs, accelerated aging of systems, and development of manufacturing techniques.

  9. Hypervelocity Impact Test Facility: A gun for hire

    NASA Astrophysics Data System (ADS)

    Johnson, Calvin R.; Rose, M. F.; Hill, D. C.; Best, S.; Chaloupka, T.; Crawford, G.; Crumpler, M.; Stephens, B.

    An affordable technique has been developed to duplicate the types of impacts observed on spacecraft, including the Shuttle, by use of a certified Hypervelocity Impact Facility (HIF) which propels particulates using capacitor driven electric gun techniques. The fully operational facility provides a flux of particles in the 10-100 micron diameter range with a velocity distribution covering the space debris and interplanetary dust particle environment. HIF measurements of particle size, composition, impact angle and velocity distribution indicate that such parameters can be controlled in a specified, tailored test designed for or by the user. Unique diagnostics enable researchers to fully describe the impact for evaluating the 'targets' under full power or load. Users regularly evaluate space hardware, including solar cells, coatings, and materials, exposing selected portions of space-qualified items to a wide range of impact events and environmental conditions. Benefits include corroboration of data obtained from impact events, flight simulation of designs, accelerated aging of systems, and development of manufacturing techniques.

  10. Test plan. Task 5, subtask 5.2: Early on-orbit TPSdebris impact tests

    NASA Technical Reports Server (NTRS)

    Greenberg, H. S.

    1994-01-01

    The limitation of damage to, and survival of, the cryogenic tankage during the on-orbit stay despite potential impact of orbital debris, may be a significant discriminator in the RHCTS trade studies described in the TA-1 trade study plan (ref. RHCTS-TSP-1) dated July 29, 1994. The objective of this early phase of an overall debris impact test program is to provide the data to support assessment of the relative suitability of integral and non integral tanks.

  11. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

    Reimus, M.A.H.; Hinckley, J.E.

    1998-12-31

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the convertor housing, failure of one fueled clad, and release of a small quantity of fuel.

  12. Simulated hail impact testing of photovoltaic solar panels

    NASA Technical Reports Server (NTRS)

    Moore, D.; Wilson, A.; Ross, R.

    1978-01-01

    Techniques used to simulate and study the effect of hail on photovoltaic solar panels are described. Simulated hail stones (frozen ice spheres projected at terminal velocity) or steel balls were applied by air guns, gravity drop, or static loading. Tests with simulated hail and steel balls yielded different results. The impact strength of 10 commercially available flat-plate photovoltaic modules was tested. It was found that none of the six panel designs incorporating clear potting silicone material as the outermost layer remained undamaged by 1-in. simulated hailstones, while a photovoltaic module equipped with a 0.188-in.-thick acrylic cover sheet would be able to withstand the impact of a 2-in.-diameter hailstone.

  13. Shock Testing the SEAWOLF Submarine, Final Environmental Impact Statement

    DTIC Science & Technology

    1998-05-01

    that would settle to the seafloor would be the top plate and crossbar, which together weigh 204 kg (450 lb). After detonation, the test array would be...but would have no significant impact on bottom structure or form. The largest possible fragment from the explosion is the top plate and crossbar...is the top plate and crossbar, which together weigh 204 kg (450 lb). Due to low oxygen levels in bottom sediments, the steel fragments would likely

  14. Data Reduction and Its Impact on Test-Analysis Correlation

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Bark, Lindley W.

    2001-01-01

    A research project has been initiated to improve crash test and analysis correlation. The research has focused on two specimen types: simple metallic beams and plates; and a representative composite fuselage section. Impact tests were performed under carefully controlled conditions. In addition, the specimens were densely instrumented to enable not only correlation with finite element simulations, but to also assess the repeatability of the data. Simulations utilizing a detailed finite element model were executed in a nonlinear transient dynamic code. The results presented in this paper concentrate on the effect of several data reduction processes, to include filtering frequency and sampling rate, on the correlation accuracy.

  15. Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials

    NASA Technical Reports Server (NTRS)

    Agrawal, Parul; Munk, Michelle M.; Glaab, Louis J.

    2013-01-01

    There are several harsh space environments that could affect thermal protection systems and in turn pose risks to the atmospheric entry vehicles. These environments include micrometeoroid impact, extreme cold temperatures, and ionizing radiation during deep space cruise, all followed by atmospheric entry heating. To mitigate these risks, different thermal protection material samples were subjected to multiple tests, including hyper velocity impact, cold soak, irradiation, and arcjet testing, at various NASA facilities that simulated these environments. The materials included a variety of honeycomb packed ablative materials as well as carbon-based non-ablative thermal protection systems. The present paper describes the results of the multiple test campaign with a focus on arcjet testing of thermal protection materials. The tests showed promising results for ablative materials. However, the carbon-based non-ablative system presented some concerns regarding the potential risks to an entry vehicle. This study provides valuable information regarding the capability of various thermal protection materials to withstand harsh space environments, which is critical to sample return and planetary entry missions.

  16. West Valley Demonstration Project full-scale canister impact tests

    SciTech Connect

    Whittington, K.F.; Alzheimer, J.M.; Lutz, C.E.

    1995-09-01

    Five West Valley Nuclear Services (WVNS) high-level waste (HLW) canisters were impact tested during 1994 to demonstrate compliance with the drop test requirements of the Waste Acceptance Product Specifications. The specifications state that the canistered waste form must be able to survive a 7{minus}m (23 ft) drop unbreached. The 10-gauge (0.125 in. wall thickness) stainless steel canisters were approximately 85% filled with simulated vitrified waste and weighed about 2100 kg (4600 lb). Each canister was dropped vertically from a height of 7 m (23 ft) onto an essentially unyielding surface. The integrity of the canister was determined by the application and analysis of strain circles, dimensional measurements, and helium leak testing. The canisters were also visually inspected before and after the drop for physical damage. The results of the impact test verify that the canisters survived the 7{minus}m drops unbreached. Therefore, these results demonstrate that the reference canister meets the drop test specification of the Waste Acceptance Product Specification.

  17. Sand Impact Tests of a Half-Scale Crew Module Boilerplate Test Article

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.; Hardy, Robin C.

    2012-01-01

    Although the Orion Multi-Purpose Crew Vehicle (MPCV) is being designed primarily for water landings, a further investigation of launch abort scenarios reveals the possibility of an onshore landing at Kennedy Space Center (KSC). To gather data for correlation against simulations of beach landing impacts, a series of sand impact tests were conducted at NASA Langley Research Center (LaRC). Both vertical drop tests and swing tests with combined vertical and horizontal velocity were performed onto beds of common construction-grade sand using a geometrically scaled crew module boilerplate test article. The tests were simulated using the explicit, nonlinear, transient dynamic finite element code LS-DYNA. The material models for the sand utilized in the simulations were based on tests of sand specimens. Although the LSDYNA models provided reasonable predictions for peak accelerations, they were not always able to track the response through the duration of the impact. Further improvements to the material model used for the sand were identified based on results from the sand specimen tests.

  18. Shape Distribution of Fragments from Microsatellite Impact Tests

    NASA Technical Reports Server (NTRS)

    Liou, J.C.; Hanada, T.

    2009-01-01

    Fragment shape is an important factor for conducting reliable orbital debris damage assessments for critical space assets, such as the International Space Station. To date, seven microsatellite impact tests have been completed as part of an ongoing collaboration between Kyushu University and the NASA Orbital Debris Program Office. The target satellites ranged in size from 15 cm 15 cm 15 cm to 20 cm 20 cm 20 cm. Each target satellite was equipped with fully functional electronics, including circuits, battery, and transmitter. Solar panels and multi-layer insulation (MLI) were added to the target satellites of the last two tests. The impact tests were carried out with projectiles of different sizes and impact speeds. All fragments down to about 2 mm in size were collected and analyzed based on their three orthogonal dimensions, x, y, and z, where x is the longest dimension, y is the longest dimension in the plane perpendicular to x, and z is the longest dimension perpendicular to both x and y. Each fragment was also photographed and classified by shape and material composition. This data set serves as the basis of our effort to develop a fragment shape distribution. Two distinct groups can be observed in the x/y versus y/z distribution of the fragments. Objects in the first group typically have large x/y values. Many of them are needle-like objects originating from the fragmentation of carbon fiber reinforced plastic materials used to construct the satellites. Objects in the second group tend to have small x/y values, and many of them are box-like or plate-like objects, depending on their y/z values. Each group forms the corresponding peak in the x/y distribution. However, only one peak can be observed in the y/z distribution. These distributions and how they vary with size, material type, and impact parameters will be described in detail within the paper.

  19. Target Soil Impact Verification: Experimental Testing and Kayenta Constitutive Modeling.

    SciTech Connect

    Broome, Scott Thomas; Flint, Gregory Mark; Dewers, Thomas; Newell, Pania

    2015-11-01

    This report details experimental testing and constitutive modeling of sandy soil deformation under quasi - static conditions. This is driven by the need to understand constitutive response of soil to target/component behavior upon impact . An experimental and constitutive modeling program was followed to determine elastic - plastic properties and a compressional failure envelope of dry soil . One hydrostatic, one unconfined compressive stress (UCS), nine axisymmetric compression (ACS) , and one uniaxial strain (US) test were conducted at room temperature . Elastic moduli, assuming isotropy, are determined from unload/reload loops and final unloading for all tests pre - failure and increase monotonically with mean stress. Very little modulus degradation was discernable from elastic results even when exposed to mean stresses above 200 MPa . The failure envelope and initial yield surface were determined from peak stresses and observed onset of plastic yielding from all test results. Soil elasto - plastic behavior is described using the Brannon et al. (2009) Kayenta constitutive model. As a validation exercise, the ACS - parameterized Kayenta model is used to predict response of the soil material under uniaxial strain loading. The resulting parameterized and validated Kayenta model is of high quality and suitable for modeling sandy soil deformation under a range of conditions, including that for impact prediction.

  20. Machine for development impact tests in sports seats and similar

    NASA Astrophysics Data System (ADS)

    Gonçalves, R. M.

    2015-10-01

    This paper describes the stages of development of a machine to perform impact tests in sport seats, seats for spectators and multiple seats. This includes reviews and recommendations for testing laboratories that have needs similar to the laboratory where unfolded this process.The machine was originally developed seeking to meet certain impact tests in accordance with the NBR15925 standards; 15878 and 16031. The process initially included the study of the rules and the election of the tests for which the machine could be developed and yet all reports and outcome of interaction with service providers and raw materials.For operating facility, it was necessary to set entirely the machine control, which included the concept of dialogue with operator, the design of the menu screens and the procedures for submission and registration of results. To ensure reliability in the process, the machine has been successfully calibrated according to the requirements of the Brazilian network of calibration.The criticism to this enterprise covers the technical and economic aspects involved and points out the main obstacles that were needed to overcome.

  1. Single and multiple impact ignition of new and aged high explosives in the Steven Impact Test

    SciTech Connect

    Chidester, S K; DePiero, A H; Garza, R G; Tarver, C M

    1999-06-01

    Threshold impact velocities for ignition of exothermic reaction were determined for several new and aged HMX-based solid high explosives using three types of projectiles in the Steven Test. Multiple impact threshold velocities were found to be approximately 10% lower in damaged charges that did not react in one or more prior impacts. Projectiles with protrusions that concentrate the friction work in a small volume of explosive reduced the threshold velocities by approximately 30%. Flat projectiles required nearly twice as high velocities for ignition as rounded projectiles. Blast overpressure gauges were used for both pristine and damaged charges to quantitatively measure reaction violence. Reactive flow calculations of single and multiple impacts with various projectiles suggest that the ignition rates double in damaged charges.

  2. Spur Gear Laser Surface Hardening MM/T Program

    DTIC Science & Technology

    1982-03-01

    case profile for D6AC before ....... 34 and after temper 8. Charpy V-Notch impact test specimen configuration. 35 9. Charpy V-Notch impact strength of...analysis of D6AC ......................... 32 4. Longitudinal Charpy V-Notch impact strength ....... 36 of D6AC at two different hardness levels from...TOLERANCE:,.001 UNLESS SPECIFIED OTHERWISE ALL DIMENSIONS IN INCHES. Figure 8. Charpy V-notch impact test specimen configuration. 35 A TABLE 4

  3. Cycom 977-2 Composite Material: Impact Test Results

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Herald, Stephen; Watkins, Casey

    2005-01-01

    The reaction frequency data from 13A testing by MSFC and WSTF appear well behaved for the sample number used by each and exhibit the same type of energy level dependency. The reaction frequency shift in energy level is unexplained at this time. All the 13A data suggest that only a small amount of material is consumed when reactions take place. At ambient pressure, most of not all reactions are quenched as indicated by the small mass loss. As test pressure is increased in LOX using 13B results. Cycom does not support initiation of reactions or propagations of reactions in GOX at 100 psis based on tests at MSFC and WSTF at 72 ft-lb impact energy. No batch effect was identified in LOX or GOX.

  4. A Blind Test of the Younger Dryas Impact Hypothesis

    PubMed Central

    Holliday, Vance

    2016-01-01

    The Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., ~12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the ~12.8ka zone at the Lubbock Lake archaeological site (LL) in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka). Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB. PMID:27391147

  5. A Blind Test of the Younger Dryas Impact Hypothesis.

    PubMed

    Holliday, Vance; Surovell, Todd; Johnson, Eileen

    2016-01-01

    The Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., ~12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the ~12.8ka zone at the Lubbock Lake archaeological site (LL) in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka). Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB.

  6. Estimating the Impacts of Educational Interventions Using State Tests or Study-Administered Tests. NCEE 2012-4016

    ERIC Educational Resources Information Center

    Olsen, Robert B.; Unlu, Fatih; Price, Cristofer; Jaciw, Andrew P.

    2011-01-01

    This report examines the differences in impact estimates and standard errors that arise when these are derived using state achievement tests only (as pre-tests and post-tests), study-administered tests only, or some combination of state- and study-administered tests. State tests may yield different evaluation results relative to a test that is…

  7. The impact of toxicity testing costs on nanomaterial regulation.

    PubMed

    Choi, Jae-Young; Ramachandran, Gurumurthy; Kandlikar, Milind

    2009-05-01

    Information about the toxicity of nanoparticles is important in determining how nanoparticles will be regulated. In the U.S., the burden of collecting this information and conducting risk assessment is placed on regulatory agencies without the budgetary means to carry out this mandate. In this paper, we analyze the impact of testing costs on society's ability to gather information about nanoparticle toxicity and whether such costs can reasonably be borne by an emerging industry. We show for the United States that costs for testing existing nanoparticles ranges from $249 million for optimistic assumptions about nanoparticle hazards (i.e., they are primarily safe and mainly require simpler screening assays) to $1.18 billion for a more comprehensive precautionary approach (i.e., all nanomaterials require long-term in vivo testing). At midlevel estimates of total corporate R&D spending, and assuming plausible levels of spending on hazard testing, the time taken to complete testing is likely to be very high (34-53 years) if all existing nanomaterials are to be thoroughly tested. These delays will only increase with time as new nanomaterials are introduced. The delays are considerably less if less-stringent yet risk-averse perspectives are used. Our results support a tiered risk-assessment strategy similar to the EU's REACH legislation for regulating toxic chemicals.

  8. How Close Is Close Enough? Testing Nonexperimental Estimates of Impact against Experimental Estimates of Impact with Education Test Scores as Outcomes. Discussion Paper No. 1242-02

    ERIC Educational Resources Information Center

    Wilde, Elizabeth Ty; Hollister, Robinson

    2002-01-01

    In this study we test the performance of some nonexperimental estimators of impacts applied to an educational intervention--reduction in class size--where achievement test scores were the outcome. We compare the nonexperimental estimates of the impacts to "true impact" estimates provided by a random-assignment design used to assess the…

  9. How Close Is Close Enough? Testing Nonexperimental Estimates of Impact against Experimental Estimates of Impact with Education Test Scores as Outcomes. Discussion Paper.

    ERIC Educational Resources Information Center

    Wilde, Elizabeth Ty; Hollister, Robinson

    This study tested the performance of nonexperimental estimators of impacts applied to a class size reduction intervention with achievement test scores as the outcome. Nonexperimental estimates of impacts were compared to "true impact" estimates provided by a random-assignment design that assessed intervention effects. Data came from…

  10. Dynamic Open-Rotor Composite Shield Impact Test Report

    NASA Technical Reports Server (NTRS)

    Seng, Silvia; Frankenberger, Charles; Ruggeri, Charles R.; Revilock, Duane M.; Pereira, J. Michael; Carney, Kelly S.; Emmerling, William C.

    2015-01-01

    The Federal Aviation Administration (FAA) is working with the European Aviation Safety Agency to determine the certification base for proposed new engines that would not have a containment structure on large commercial aircraft. Equivalent safety to the current fleet is desired by the regulators, which means that loss of a single fan blade will not cause hazard to the aircraft. NASA Glenn and Naval Air Warfare Center (NAWC) China Lake collaborated with the FAA Aircraft Catastrophic Failure Prevention Program to design and test a shield that would protect the aircraft passengers and critical systems from a released blade that could impact the fuselage. This report documents the live-fire test from a full-scale rig at NAWC China Lake. NASA provided manpower and photogrammetry expertise to document the impact and damage to the shields. The test was successful: the blade was stopped from penetrating the shield, which validates the design analysis method and the parameters used in the analysis. Additional work is required to implement the shielding into the aircraft.

  11. Water impact testing of a filament wound case

    NASA Technical Reports Server (NTRS)

    Schmidt, A. A.; Kross, D. A.

    1985-01-01

    A lightweight Filament Wound Case (FWC) Solid Rocket Booster (SRB) is being developed by NASA to increase the payload capability of the space shuttle. As with the steel boosters, the current plan is to recover the FWC SRB's after they impact the ocean at 65 to 85 ft/sec. As the boosters enter the ocean (nozzle first) the water moves away from the vehicle creating a cavity, which then collapses on the vehicle, and results in a significant loading event. To understand this loading event, tests were conducted on a quarter scale FWC model to measure cavity collapse pressure distributions, deflected shape and the effects of end conditions and pressure scaling.

  12. Dynamic Impact Analyses and Tests of Concrete Overpacks - 13638

    SciTech Connect

    Lee, Sanghoon; Cho, Sang-Soon; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog

    2013-07-01

    Concrete cask is an option for spent nuclear fuel interim storage which is prevailingly used in US. A concrete cask usually consists of metallic canister which confines the spent nuclear fuel and concrete overpack. When the overpack undergoes a severe missile impact which might be caused by a tornado or an aircraft crash, it should sustain acceptable level of structural integrity so that its radiation shielding capability and the retrievability of canister are maintained. Missile impact against a concrete overpack involves two damage modes, local damage and global damage. Local damage of concrete is usually evaluated by empirical formulas while the global damage is evaluated by finite element analysis. In many cases, those two damage modes are evaluated separately. In this research, a series of numerical simulations are performed using finite element analysis to evaluate the global damage of concrete overpack as well as its local damage under high speed missile impact. We consider two types of concrete overpack, one with steel in-cased concrete without reinforcement and the other with partially-confined reinforced concrete. The numerical simulation results are compared with test results and it is shown that appropriate modeling of material failure is crucial in this analysis and the results are highly dependent on the choice of failure parameters. (authors)

  13. Microstructural Features Controlling Mechanical Properties in Nb-Mo Microalloyed Steels. Part II: Impact Toughness

    NASA Astrophysics Data System (ADS)

    Isasti, Nerea; Jorge-Badiola, Denis; Taheri, Mitra L.; Uranga, Pello

    2014-10-01

    The present paper is the final part of a two-part paper where the influence of coiling temperature on the final microstructure and mechanical properties of Nb-Mo microalloyed steels is described. More specifically, this second paper deals with the different mechanisms affecting impact toughness. A detailed microstructural characterization and the relations linking the microstructural parameters and the tensile properties have already been discussed in Part I. Using these results as a starting point, the present work takes a step forward and develops a methodology for consistently incorporating the effect of the microstructural heterogeneity into the existing relations that link the Charpy impact toughness to the microstructure. In conventional heat treatments or rolling schedules, the microstructure can be properly described by its mean attributes, and the ductile-brittle transition temperatures measured by Charpy tests can be properly predicted. However, when different microalloying elements are added and multiphase microstructures are formed, the influences of microstructural heterogeneity and secondary hard phases have to be included in a modified equation in order to accurately predict the DB transition temperature in Nb and Nb-Mo microalloyed steels.

  14. Anisotropic Embrittlement in High-Hardness ESR 4340 Steel Forgings.

    DTIC Science & Technology

    1982-01-01

    direction which is strain-rate and humidity dependent. The anisotropy is also reflected in blunt-notch Charpy impact energy, but is absent in the sharp...evaluated both by standard Charpy impact tests and slow-bend tests on precracked Charpy specimens; sharp-crack fracture toughness (KIc) values were...Microprobe (SAM). Despite the frequent observation of intergranular fracture in Charpy impact specimens (as in Figure 3), no clear examples of

  15. Excerpts from Test Films: Langley Impacting Structures Facility, Lunar Module

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Excerpts from Test Films: Langley Impacting Structures Facility, Lunar Module. The film includes excerpts from three studies: (1) Landing characteristics of a dynamic model of the HL-10 manned lifting entry vehicle, conducted by Sandy M. Stubbs, in which the vehicle landed on water at horizontal velocities of 240- and 250-feet per second (ft/sec). (2) Dynamic model investigation of water pressures and accelerations encountered during landings of the Apollo spacecraft conducted by Sandy M. Stubbs, in which horizontal velocity was 50 ft/sec. and pitch attitude was -12 and -28 degrees. (3) Comparative landing impact tests of a 1/6-scale model as a free body under earth gravity and a tethered full-scale lunar module on the Lunar Gravity Simulator. Landing 8 is shown, with a vertical velocity of 10 ft/sec. and a horizontal velocity of 8 ft/sec. Motion pictures were taken at 400 and 64 pps. [Entire movie available on DVD from CASI as Doc ID 20070030993. Contact help@sti.nasa.gov

  16. Controlled Impact Demonstration instrumented test dummies installed in plane

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In this photograph are seen some of dummies in the passenger cabin of the B-720 aircraft. NASA Langley Research Center instrumented a large portion of the aircraft and the dummies for loads in a crashworthiness research program. In 1984 NASA Dryden Flight Research Facility and the Federal Aviation Adimistration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID). The test involved crashing a Boeing 720 aircraft with four JT3C-7 engines burning a mixture of standard fuel with an additive called Anti-misting Kerosene (AMK) designed to supress fire. In a typical aircraft crash, fuel spilled from ruptured fuel tanks forms a fine mist that can be ignited by a number of sources at the crash site. In 1984 the NASA Dryden Flight Research Facility (after 1994 a full-fledged Center again) and the Federal Aviation Administration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID), to test crash a Boeing 720 aircraft using standard fuel with an additive designed to supress fire. The additive, FM-9, a high-molecular-weight long-chain polymer, when blended with Jet-A fuel had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated crash tests. This anti-misting kerosene (AMK) cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called 'degradation' and was accomplished on the B-720 using a device called a 'degrader.' Each of the four Pratt & Whitney JT3C-7 engines had a 'degrader' built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research the NASA Langley Research Center was involved in a structural loads measurement experiment, which included having instrumented dummies filling the seats in the

  17. Comparison of Autogenous and Alloplastic Cranioplasty Materials Following Impact Testing.

    PubMed

    Wallace, Robert D; Salt, Craig; Konofaos, Petros

    2015-07-01

    Alloplastic materials are often used when significant defects exist. Benefits include no donor site morbidity, relative ease of use, limitless supply, and predictable durability. Depending on the type of alloplast, limitations include a persistent risk of extrusion and infection. Of particular interest in relation to cranioplasties is the ability of the material to provide neuroprotection. The integrity and neuroprotective properties of autologous bone flaps, polymethylmethacrylate (PMMA), and high-density porous polyethylene (PP) were evaluated following impact testing. Three groups of New Zealand white rabbits (N = 4) underwent a cranioplasty with either a bone flap, PMMA, or PP. In the control group (N = 4), the animals had no cranioplasty. At the end of the eighth week, an impact was delivered to the center of each cranioplasty. At necropsy each cranium and brain was evaluated grossly and histologically. There was a statistical significant difference among groups for the severity of the hemorrhage (P = 0.022) and the grade of cranioplasty disruption (P = 0.0045). Autologous bone was found to be the weakest of the materials tested. In this group severe injury resulted at much lower energy levels than was observed in the control, PMMA, or PP groups. Both PMMA and PP were resistant to fracture and disruption. PMMA provided the greatest neuroprotection, followed by PP. Autologous bone provided the least protection with cranioplasty disruption and severe brain injury occurring in every patient. Brain injury patterns correlated with the degree of cranioplasty disruption regardless of the cranioplasty material. Regardless of the energy of impact, lack of dislodgement generally resulted in no obvious brain injury.

  18. Impact properties of irradiated HT9 from the fuel duct of FFTF

    SciTech Connect

    Byun, Thak Sang; Lewis, W. Daniel; Toloczko, Mychailo B.; Maloy, Stuart A.

    2012-02-01

    This paper reports Charpy impact test data for the ACO-3 duct material (HT9) from the Fast Flux Test Facility (FFTF) and its archive material. Irradiation doses for the specimens were in the range of 3– 148 dpa and irradiation temperatures in the range of 378–504 *C. The impact tests were performed for the small V-notched Charpy specimens with dimensions of 3 * 4 * 27 mm at an impact speed of 3.2 m/s in a 25 J capacity machine. Irradiation lowered the upper-shelf energy (USE) and increased the transition temperatures significantly. The shift of ductile–brittle transition temperatures (DDBTT) was greater after relatively low temperature irradiation. The USE values were in the range of 5.5–6.7 J before irradiation and decreased to the range of 2–5 J after irradiation. Lower USEs were measured for lower irradiation temperatures and specimens with T-L orientation. The dose dependences of transition temperature and USE were not significant because of the radiation effect on impact behavior nearly saturated at the lowest dose of about 3 dpa. A comparison showed that the lateral expansion of specimens showed a linear correlation with absorbed impact energy, but with large scatter in the results. Size effect was also discussed to clarify the differences in the impact property data from subsize and standard specimens as well as to provide a basis for comparison of data from different specimens. The USE and DDBTT data from different studies were compared.

  19. Experimental impact testing and analysis of composite fan cases

    NASA Astrophysics Data System (ADS)

    Vander Klok, Andrew Joe

    For aircraft engine certification, one of the requirements is to demonstrate the ability of the engine to withstand a fan blade-out (FBO) event. A FBO event may be caused by fatigue failure of the fan blade itself or by impact damage of foreign objects such as bird strike. An un-contained blade can damage flight critical engine components or even the fuselage. The design of a containment structure is related to numerous parameters such as the blade tip speed; blade material, size and shape; hub/tip diameter; fan case material, configuration, rigidity, etc. To investigate all parameters by spin experiments with a full size rotor assembly can be prohibitively expensive. Gas gun experiments can generate useful data for the design of engine containment cases at much lower costs. To replicate the damage modes similar to that on a fan case in FBO testing, the gas gun experiment has to be carefully designed. To investigate the experimental procedure and data acquisition techniques for FBO test, a low cost, small spin rig was first constructed. FBO tests were carried out with the small rig. The observed blade-to-fan case interactions were similar to those reported using larger spin rigs. The small rig has the potential in a variety of applications from investigating FBO events, verifying concept designs of rotors, to developing spin testing techniques. This rig was used in the developments of the notched blade releasing mechanism, a wire trigger method for synchronized data acquisition, high speed video imaging and etc. A relationship between the notch depth and the release speed was developed and verified. Next, an original custom designed spin testing facility was constructed. Driven by a 40HP, 40,000rpm air turbine, the spin rig is housed in a vacuum chamber of phi72inx40in (1829mmx1016mm). The heavily armored chamber is furnished with 9 viewports. This facility enables unprecedented investigations of FBO events. In parallel, a 15.4ft (4.7m) long phi4.1inch (105mm

  20. Interface Effects on the Quasi-Static and Impact Toughness of Discontinuously Reinforced Aluminum Laminates

    NASA Astrophysics Data System (ADS)

    Osman, Todd M.; Hassan, Hala A.; Lewandowski, John J.

    2008-08-01

    Trilayer laminates consisting of two layers of aluminum alloy 7093 surrounding one layer of 7093/SiC/15 p were produced via two roll-bonding techniques as well as by adhesive bonding. The effects of systematic changes in interface characteristics ( i.e., weak bond via roll bonding with a thin ductile interlayer material, stronger bond via roll bonding without a thin ductile interlayer, and strongest bond via adhesive bonding with a semibrittle material) on the subsequent laminate toughness was studied. The fracture resistance of the laminates and the constituent materials was examined via instrumented Charpy notched impact testing in the crack-arrester orientation as well as by fracture-toughness testing of bend bars tested in the crack-divider and the crack-arrester orientations. The notched impact resistance of the trilayer crack-arrester laminates was found to be greater than both monolithic 7093/SiC/15 p and 7093 samples of similar global thickness. The laminated structure promoted crack arrest, deflection, and large-scale deformation of the unreinforced layers, producing R-curve behavior. The tendency for interface delamination was predicted and confirmed based on recent mechanics-based analyses. The trilayer laminate structures tested in the crack-divider orientation exhibited a greater R-curve than either of the 7093/SiC/15 p or 7093 samples tested at similar global thickness. Both types of roll-bonded laminates ( i.e., stronger interface and weak interface containing a thin metal interlayer) exhibited a greater enhancement in Charpy impact toughness and mode I fracture toughness than did the adhesively bonded ( i.e., semibrittle interface) laminates. These relative improvements in toughness were rationalized by estimating the contributions to energy absorption by the delamination and crack bridging in these systems and by the effects of the interface type on these processes. These results are generally relevant to the performance of these materials under

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  2. Post-irradiation mechanical tests on F82H EB and TIG welds

    NASA Astrophysics Data System (ADS)

    Rensman, J.; van Osch, E. V.; Horsten, M. G.; d'Hulst, D. S.

    2000-12-01

    The irradiation behaviour of electron beam (EB) and tungsten inert gas (TIG) welded joints of the reduced-activation martensitic steel IEA heat F82H-mod. was investigated by neutron irradiation experiments in the high flux reactor (HFR) in Petten. Mechanical test specimens, such as tensile specimens and KLST-type Charpy impact specimens, were neutron irradiated up to a dose level of 2-3 dpa at a temperature of 300°C in the HFR reactor in Petten. The tensile results for TIG and EB welds are as expected with practically no strain hardening capacity left. Considering impact properties, there is a large variation in impact properties for the TIG weld. The irradiation tends to shift the DBTT of particularly the EB welds to very high values, some cases even above +250°C. PWHT of EB-welded material gives a significant improvement of the DBTT and USE compared to the as-welded condition.

  3. RTM370 Polyimide Braided Composites: Characterization and Impact Testing

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Revilock, Duane M.; Ruggeri, Charles R.; Criss, Jim M., Jr.; Mintz, Eric A.

    2013-01-01

    RTM370 imide oligomer based on 2,3,3',4'-biphenyl dianhydride (a-BPDA), 3,4'-oxydianiline (3,4'-ODA) and terminated with the 4-phenylethynylphthalic (PEPA) endcap has been shown to exhibit a low melt viscosity (10-30 poise) at 280 C with a pot-life of 1-2 h and a high cured glass transition temperature (Tg) of 370 C. RTM370 resin has been successfully fabricated into composites reinforced with T650-35 carbon fabrics by resin transfer molding (RTM). RTM370 composites display excellent mechanical properties up to 327 C (620 F), and outstanding property retention after aging at 288degC (550 F) for 1000 h, and under hot-wet conditions. In ballistic impact testing, RTM370 triaxial braided T650-35 carbon fiber composites exhibited enhanced energy absorption at 288 C (550 F) compared to ambient temperature.

  4. IMPROVED BAR IMPACT TESTS USING A PHOTONIC DOPPLER VELOCIMETER

    SciTech Connect

    Bless, S. J.; Tolman, J.; Levinson, S.; Nguyen, J.

    2009-12-28

    Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and a glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression, and the 'steady state' strength. For borosilicate glass and soda lime glass, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic (25% spinel) was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic, as opposed to intrinsic property.

  5. IMPROVED BAR IMPACT TESTS USING A PHOTONIC DOPPLER VELOCIMETER

    SciTech Connect

    Bless, S J; Tolman, J; Levinson, S; Nguyen, J

    2009-08-24

    Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and a glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression, and the 'steady state' strength. For borosilicate glass and soda lime glass, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic (25% spinel) was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic, as opposed to intrinsic property.

  6. Quantitative testing of robustness on superomniphobic surfaces by drop impact.

    PubMed

    Nguyen, Thi Phuong Nhung; Brunet, Philippe; Coffinier, Yannick; Boukherroub, Rabah

    2010-12-07

    The quality of a liquid-repellent surface is quantified by both the apparent contact angle θ(0) that a sessile drop adopts on it and the value of the liquid pressure threshold the surface can withstand without being impaled by the liquid, hence maintaining a low-friction condition. We designed surfaces covered with nanowires obtained by the vapor-liquid-solid (VLS) growth technique that are able to repel most of the existing nonpolar liquids including those with very low surface tension as well as many polar liquids with moderate to high surface tension. These superomniphobic surfaces exhibit apparent contact angles ranging from 125 to 160° depending on the liquid. We tested the robustness of the surfaces against impalement by carrying out drop impact experiments. Our results show how this robustness depends on Young's contact angle θ(0) related to the surface tension of the liquid and that the orientational growth of nanowires is a favorable factor for robustness.

  7. The Effect of Silicon Content on Impact Toughness of T91 Grade Steels

    NASA Astrophysics Data System (ADS)

    Roy, Ajit; Kumar, Pankaj; Maitra, Debajyoti

    2009-03-01

    The impact resistance of silicon (Si)-containing modified 9Cr-1Mo steels has been investigated within a temperature regime of -40 to 440 °C using the Charpy method. The results indicate that the energies absorbed in fracturing the tested specimens were substantially lower at temperatures of -40, 25, and 75 °C compared to those at elevated temperatures. Lower impact energies and higher ductile-to-brittle-transition-temperatures (DBTTs) were observed with the steels containing 1.5 and 1.9 wt.% Si. The steels containing higher Si levels exhibited both ductile and brittle failures at elevated temperatures. However, at lower temperatures, brittle failures characterized by cleavage and intergranular cracking were observed for all four tested materials.

  8. Effect of heat treatment on the mixed-mode impact behavior of a 6061 aluminum alloy

    SciTech Connect

    Manoharan, M.

    1996-10-15

    In the mixed mode fracture toughness tests, the use of a modified compact tension specimen has enabled the testing of materials under a variety of combinations of mode I and mode III loadings. By using appropriately defined mixed-mode versions of the stress intensity factor K and the J integral, the susceptibility of these materials to mixed-mode fracture can be quantified. In addition to compact tension specimens, three point bend specimens with a inclined crack can also be used to determine the mixed-mode fracture behavior of materials. The aim of the present study was to study the feasibility of extending the mixed mode fracture concept to impact testing using a charpy type test specimen.

  9. Wavelet analysis in ecology and epidemiology: impact of statistical tests

    PubMed Central

    Cazelles, Bernard; Cazelles, Kévin; Chavez, Mario

    2014-01-01

    Wavelet analysis is now frequently used to extract information from ecological and epidemiological time series. Statistical hypothesis tests are conducted on associated wavelet quantities to assess the likelihood that they are due to a random process. Such random processes represent null models and are generally based on synthetic data that share some statistical characteristics with the original time series. This allows the comparison of null statistics with those obtained from original time series. When creating synthetic datasets, different techniques of resampling result in different characteristics shared by the synthetic time series. Therefore, it becomes crucial to consider the impact of the resampling method on the results. We have addressed this point by comparing seven different statistical testing methods applied with different real and simulated data. Our results show that statistical assessment of periodic patterns is strongly affected by the choice of the resampling method, so two different resampling techniques could lead to two different conclusions about the same time series. Moreover, our results clearly show the inadequacy of resampling series generated by white noise and red noise that are nevertheless the methods currently used in the wide majority of wavelets applications. Our results highlight that the characteristics of a time series, namely its Fourier spectrum and autocorrelation, are important to consider when choosing the resampling technique. Results suggest that data-driven resampling methods should be used such as the hidden Markov model algorithm and the ‘beta-surrogate’ method. PMID:24284892

  10. Wavelet analysis in ecology and epidemiology: impact of statistical tests.

    PubMed

    Cazelles, Bernard; Cazelles, Kévin; Chavez, Mario

    2014-02-06

    Wavelet analysis is now frequently used to extract information from ecological and epidemiological time series. Statistical hypothesis tests are conducted on associated wavelet quantities to assess the likelihood that they are due to a random process. Such random processes represent null models and are generally based on synthetic data that share some statistical characteristics with the original time series. This allows the comparison of null statistics with those obtained from original time series. When creating synthetic datasets, different techniques of resampling result in different characteristics shared by the synthetic time series. Therefore, it becomes crucial to consider the impact of the resampling method on the results. We have addressed this point by comparing seven different statistical testing methods applied with different real and simulated data. Our results show that statistical assessment of periodic patterns is strongly affected by the choice of the resampling method, so two different resampling techniques could lead to two different conclusions about the same time series. Moreover, our results clearly show the inadequacy of resampling series generated by white noise and red noise that are nevertheless the methods currently used in the wide majority of wavelets applications. Our results highlight that the characteristics of a time series, namely its Fourier spectrum and autocorrelation, are important to consider when choosing the resampling technique. Results suggest that data-driven resampling methods should be used such as the hidden Markov model algorithm and the 'beta-surrogate' method.

  11. Impact of experimental hypercalcemia on routine haemostasis testing

    PubMed Central

    Lippi, Giuseppe; Salvagno, Gian Luca; Brocco, Giorgio; Gelati, Matteo; Favaloro, Emmanuel J.

    2017-01-01

    Background The blood to anticoagulant ratio is standardized according to the physiological calcium concentration in blood samples conventionally used for hemostasis testing. Specifically, one fixed volume of 0.109 mmol/L sodium citrate is added to 9 volumes of blood. Since little is known about the impact of hypercalcemia on the calcium-binding capacity of citrate, this study was planned to investigate the effect of experimental hypercalcemia on routine hemostasis testing. Methods Fifteen pooled citrated plasmas with matching lithium-heparin pooled plasma from patients with different values of prothrombin time (PT) were divided in three aliquots of 0.6mL each. The first paired aliquots of both citrate and lithium-heparin plasma were supplemented with 60μL of saline, the second paired aliquots with 30μL of saline and 30μL of calcium chloride and the third paired aliquots with 60μL of calcium chloride. Total and ionized calcium was measured in all aliquots of citrate and lithium-heparin plasma, whereas PT, activated partial thromboplastin time (APTT) and fibrinogen were measured in citrate plasma aliquots. Results Total calcium concentration gradually increased in both lithium-heparin and citrate plasma aliquots 2 and 3 compared to baseline aliquot 1. The concentration of ionized calcium also gradually increased in lithium-heparin plasma aliquots 2 and 3, whereas it remained immeasurable (i.e., <0.10 mmol/L) in all citrate plasma aliquots. No significant differences were observed for values of PT, APTT and fibrinogen in citrate plasma aliquots 2 and 3 compared to the baseline aliquot 1, with a mean bias was always comprised within the desirable quality specifications derived from biological variability data. Conclusion Hypercalcemia, up to severe hypercalcemia does not generate significant bias in results of first-line coagulations tests, so that hypothetical consideration of adjusting citrate-blood ratio is unjustified in hypercalcemic patients. PMID:28362859

  12. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  13. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  14. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  15. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  16. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  17. Measurement of Satellite Impact Test Fragments for Modeling Orbital Debris

    NASA Technical Reports Server (NTRS)

    Hill, Nicole M.

    2009-01-01

    There are over 13,000 pieces of catalogued objects 10cm and larger in orbit around Earth [ODQN, January 2009, p12]. More than 6000 of these objects are fragments from explosions and collisions. As the earth-orbiting object count increases, debris-generating collisions in the future become a statistical inevitability. To aid in understanding this collision risk, the NASA Orbital Debris Program Office has developed computer models that calculate quantity and orbits of debris both currently in orbit and in future epochs. In order to create a reasonable computer model of the orbital debris environment, it is important to understand the mechanics of creation of debris as a result of a collision. The measurement of the physical characteristics of debris resulting from ground-based, hypervelocity impact testing aids in understanding the sizes and shapes of debris produced from potential impacts in orbit. To advance the accuracy of fragment shape/size determination, the NASA Orbital Debris Program Office recently implemented a computerized measurement system. The goal of this system is to improve knowledge and understanding of the relation between commonly used dimensions and overall shape. The technique developed involves scanning a single fragment with a hand-held laser device, measuring its size properties using a sophisticated software tool, and creating a three-dimensional computer model to demonstrate how the object might appear in orbit. This information is used to aid optical techniques in shape determination. This more automated and repeatable method provides higher accuracy in the size and shape determination of debris.

  18. Test Directions as a Critical Component of Test Design: Best Practices and the Impact of Examinee Characteristics

    ERIC Educational Resources Information Center

    Lakin, Joni M.

    2014-01-01

    The purpose of test directions is to familiarize examinees with a test so that they respond to items in the manner intended. However, changes in educational measurement as well as the U.S. student population present new challenges to test directions and increase the impact that differential familiarity could have on the validity of test score…

  19. Predictive genetic testing for cardiovascular diseases: impact on carrier children.

    PubMed

    Meulenkamp, Tineke M; Tibben, Aad; Mollema, Eline D; van Langen, Irene M; Wiegman, Albert; de Wert, Guido M; de Beaufort, Inez D; Wilde, Arthur A M; Smets, Ellen M A

    2008-12-15

    We studied the experiences of children identified by family screening who were found to be a mutation carrier for a genetic cardiovascular disease (Long QT Syndrome (LQTS), Hypertrophic Cardiomyopathy (HCM), Familial Hypercholesterolemia (FH)). We addressed the (a) manner in which they perceive their carrier status, (b) impact on their daily lives, and (c) strategy used to cope with these consequences. Children (aged 8-18) who tested positive for LQTS (n=11), HCM (n=6) or FH (n=16), and their parents participated in semi-structured audiotaped interviews. Interview topics included illness perception, use of medication, lifestyle modifications, worries, and coping. Each interview was coded by two researchers. The qualitative analysis was guided by Leventhal's model of self-regulation. The children were overall quite articulate about the disease they were tested for, including its mode of inheritance. They expressed positive future health perceptions, but feelings of controllability varied. Adherence and side-effects were significant themes with regard to medication-use. Refraining from activities and maintaining a non-fat diet were themes concerning lifestyle modifications. Some children spontaneously reported worries about the possibility of dying and frustration about being different from peers. Children coped with these worries by expressing faith in the effectiveness of medication, trying to be similar to peers or, in contrast, emphasizing their "being different." Children generally appeared effective in the way they coped with their carrier status and its implications. Nevertheless, dealing with the daily implications of their condition remains difficult in some situations, warranting continued availability of psychosocial support.

  20. Tensile and impact properties of General Atomics 832864 heat of V-4Cr-4Ti alloy

    SciTech Connect

    Tsai, H.; Nowicki, L.J.; Gazda, J.; Billone, M.C.; Smith, D.L.; Johnson, W.R.; Trester, P.

    1998-09-01

    A 1300-kg heat of V-4Cr-4Ti alloy was procured by General Atomics (GA) for the DIII-D radiative divertor program. To determine the mechanical properties of this alloy, tensile and Charpy tests were conducted on specimens prepared from pieces of 4.8-mm-thick as-rolled plates, a major product form for the DIII-D application. The tensile tests were conducted at three temperatures, 26, 280 and 380 C, the last two being the anticipated peak temperatures during DIII-D boronization and postvent bake-out, respectively. Results from these tests show that the tensile and impact properties of the 832864 heat are comparable to those of the other smaller V-(4-5)Cr-(4-5)Ti alloy heats previously developed by the US Fusion Materials Program and that scale-up of vanadium alloy production can be successfully achieved as long as reasonable process control is implemented.

  1. Influence of Constituent Materials on the Impact Toughness and Fracture Mechanisms of Hot-Roll-Bonded Aluminum Multilayer Laminates

    NASA Astrophysics Data System (ADS)

    Cepeda-Jiménez, C. M.; Hidalgo, P.; Pozuelo, M.; Ruano, O. A.; Carreño, F.

    2010-01-01

    Two aluminum multilayer laminates have been processed by hot roll bonding following similar processing paths. The first one is constituted by alternated Al 2024 and Al 1050 layers (ALH19) and the second one by alternated Al 7075 and Al 1050 layers (ADH19). The influence of the constituent materials in the multilayer laminates both during the processing at high temperature and during the subsequent mechanical characterization has been analyzed. The mechanical behavior of the as-received materials at the processing conditions has been characterized by hot torsion. Multilayer laminates have been tested at room temperature under impact Charpy tests, three-point bend tests, and shear tests on the interfaces. The relative toughness increase compared to the constituent materials was much higher for the ADH19 laminate based on the high-strength Al 7075 alloy than for the ALH19 laminate. This is attributed to the different fracture mechanism.

  2. Generic analyses for evaluation of low Charpy upper-shelf energy effects on safety margins against fracture of reactor pressure vessel materials

    SciTech Connect

    Dickson, T.L.

    1993-07-01

    Appendix G to 10 CFR Part 50 requires that reactor pressure vessel beltline material maintain Charpy upper-shelf energies of no less than 50 ft-lb during the plant operating life, unless it is demonstrated in a manner approved by the Nuclear Regulatory Commission (NRC), that lower values of Charpy upper-shelf energy provide margins of safety against fracture equivalent to those in Appendix G to Section XI of the ASME Code. Analyses based on acceptance criteria and analysis methods adopted in the ASME Code Case N-512 are described herein. Additional information on material properties was provided by the NRC, Office of Nuclear Regulatory Research, Materials Engineering Branch. These cases, specified by the NRC, represent generic applications to boiling water reactor and pressurized water reactor vessels. This report is designated as HSST Report No. 140.

  3. High-Stakes Standardized Testing & Marginalized Youth: An Examination of the Impact on Those Who Fail

    ERIC Educational Resources Information Center

    Kearns, Laura-Lee

    2011-01-01

    This study examines the impact of high-stakes, large-scale, standardized literacy testing on youth who have failed the Ontario Secondary School Literacy Test. Interviews with youth indicate that the unintended impact of high-stakes testing is more problematic than policy makers and educators may realize. In contrast to literacy policy's aims to…

  4. 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.

  5. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  6. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  7. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  8. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  9. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  10. Hypervelocity Impact Testing of Space Station Freedom Solar Cells

    NASA Technical Reports Server (NTRS)

    Christie, Robert J.; Best, Steve R.; Myhre, Craig A.

    1994-01-01

    Solar array coupons designed for the Space Station Freedom electrical power system were subjected to hypervelocity impacts using the HYPER facility in the Space Power Institute at Auburn University and the Meteoroid/Orbital Debris Simulation Facility in the Materials and Processes Laboratory at the NASA Marshall Space Flight Center. At Auburn, the solar cells and array blanket materials received several hundred impacts from particles in the micron to 100 micron range with velocities typically ranging from 4.5 to 10.5 km/s. This fluence of particles greatly exceeds what the actual components will experience in low earth orbit. These impacts damaged less than one percent of total area of the solar cells and most of the damage was limited to the cover glass. There was no measurable loss of electrical performance. Impacts on the array blanket materials produced even less damage and the blanket materials proved to be an effective shield for the back surface of the solar cells. Using the light gas gun at MSFC, one cell of a four cell coupon was impacted by a 1/4 inch spherical aluminum projectile with a velocity of about 7 km/s. The impact created a neat hole about 3/8 inch in diameter. The cell and coupon were still functional after impact.

  11. The Impact of Socioeconomic Status on High Stakes Testing Reexamined

    ERIC Educational Resources Information Center

    Baker, Melissa; Johnston, Pattie

    2010-01-01

    High-stakes testing plays a critical role in education today in the United States. Every state uses a high-stakes test to comply with the No Child Left Behind (NCLB) mandate. While many believe high-stakes testing is an acceptable and accurate way to measure students' learning, one has to ask whether high stakes testing is an effective measurement…

  12. Impact behavior of reduced-activation steels irradiated to 24 dpa*1

    NASA Astrophysics Data System (ADS)

    Klueh, R. L.; Alexander, D. J.

    1996-10-01

    Charpy impact tests were previously conducted on eight chromium-tungsten steels after irradiation at 365°C to 6-8 and 15-17 dpa in the Fast Flux Test Facility. These same steels, which range in concentration from 2.25 to 12 wt% (all steels contained 0.1%C), have now been irradiated to 20-24 dpa under the same conditions. Post-irradiation Charpy impact tests after 20-24 dpa showed that the loss of impact toughness, as measured by an increase in the ductile—brittle transition temperature (DBTT) and a decrease in the upper-shelf energy, remained relatively unchanged from the values after 15-17 dpa. As before, the most irradiation-resistant steels were two 9% Cr steels: the DBTT of a 9Cr2W0.25V steel increased 59°C, and for the same composition with an addition of 0.07% Ta, the DBTT increased only 21°C. The other steels developed shifts in DBTT of 100 to 300°C. A 2.25% Cr steel with 2% W and 0.25% V was less severely affected by irradiation than 2.25% Cr steels with 0.25% V and no tungsten, 2% W and no vanadium, and with 1% W and 0.25% V. Steels with 5 and 12% Cr, 2% W, and 0.25% V had properties between those of the 2.25Cr and 9Cr steels.

  13. Ignition of nonmetallic materials by impact of high-pressure oxygen. II - Evaluation of repeatability of pneumatic impact test

    NASA Technical Reports Server (NTRS)

    Schmidt, Naomi; Moffett, Gary E.; Pedley, Michael D.; Linley, Larry J.

    1989-01-01

    The gaseous oxygen pneumatic impact test is used to evaluate the suitability of nonmetallic materials for use in high-pressure oxygen systems. The test was evaluated by testing the reactivity of four materials over a range of impact pressures. The evaluation also investigated the effect of valve opening time and other test variables on the frequency of reaction. The variability of the data obtained for each test material was too large for the test method to be capable of distinguishing other than gross differences in the reactivity of materials. No relation was found between this variability and changes in valve opening time and other test variables. The materials studied were found to be unacceptable for use as reference standards. Because of the high variability of the test data, it is recommended that new methods be developed for evaluating the suitability of materials for use in high-pressure oxygen systems.

  14. A Study of the "toss Factor" in the Impact Testing of Cermets by the Izod Pendulum Test

    NASA Technical Reports Server (NTRS)

    Probst, H B; Mchenry, Howard T

    1957-01-01

    The test method presented shows that the "toss energy" contributed by the apparatus for brittle materials is negligible. The total toss energy is considered to consist of two components. (a) recovered stored elastic energy and (b) kinetic energy contributed directly by the apparatus. The results were verified by high-speed motion pictures of the test in operation. From these photographs, velocities of tossed specimens were obtained and toss energy computed. In addition, impact energies of some titanium carbide base cermets and high-temperature alloys, as measured by the low-capacity Izod pendulum test, compare well with impact energies measured by the NACA drop test.

  15. 46 CFR 154.605 - Toughness test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Toughness test. 154.605 Section 154.605 Shipping COAST....605 Toughness test. (a) Each toughness test under §§ 154.610 through 154.625 must meet Subpart 54.05 of this chapter. (b) If subsize test specimens are used for the Charpy V-notch toughness test,...

  16. Experimental and numerical analysis of Al6063 duralumin using Taylor impact test

    NASA Astrophysics Data System (ADS)

    Kruszka, L.; Anaszewicz, Ł.; Janiszewski, J.; Grązka, M.

    2012-08-01

    The paper presents results of experimental and numerical analysis of dynamic behaviour Al6063 duralumin. Dynamical experiments were made using Taylor impact test. Experimental results at next step of study were used in numerical analyses of dynamic yield stress of tested material and model parameters of the Johnson-Cook constitutive equation. The main aim of this analysis is to find out dynamical properties of Al6063 duralumin tested in Taylor impact test.

  17. Impact of the introduction of rapid HIV testing in the Voluntary Counselling and Testing sites network of Catalonia, Spain.

    PubMed

    Fernàndez-Lopez, L; Rifà, B; Pujol, F; Becerra, J; Pérez, M; Meroño, M; Zaragoza, K; Rafel, A; Díaz, O; Avellaneda, A; Casado, M J; Giménez, A; Casabona, J

    2010-06-01

    Rapid HIV antibody tests, which provide results within 15-60 minutes, can help reduce the number of unrecognized infections by improving access to testing facilities and increase the number of people tested who know their results. After an acceptability study, rapid HIV testing was first implemented in Catalonia in 2007 within the community-based Voluntary Counselling and Testing sites network. One year after implementation, an increase of 102.9% has been observed in the number of tests performed, ranging from 8.4% to 328.3% according to the site. Despite the important immediate impact of rapid HIV testing on the number of tests performed, there was no significant change in the proportion of tests that were positive. Rapid HIV testing can help increase access to testing, but it should be complemented with specific outreach programmes targeting the most vulnerable subgroups.

  18. Tests for Determining Failure Criteria of Ceramics under Ballistic Impact

    DTIC Science & Technology

    1992-06-01

    conclude that pressure/shear tests in these two configurations with rear surface laser diagnostics and with appropriate constitutive analysis are...Shear Test 18 Hxperimental Technique 18 Analysis Techniques 23 Results 25 Pressure/Shear Tests 25 Analyses 30 Discussion 39 4 OTHER...TDI cannot. Analysis Techniques The extraction of stresses, strains, and other mechanical variables from the transverse velocity history recorded

  19. Subtask 12D2: Baseline impact properties of vanadium alloys

    SciTech Connect

    Chung, H.M.; Loomis, B.A.; Smith, D.L.

    1995-03-01

    The objective of this work is to determine the baseline impact properties of vanadium-base alloys as a function of compositional variables. Up-to-date results on impact properties of unirradiated V, V-Ti, V-Cr-Ti and V-Ti-Si alloys are presented and reviewed in this paper, with an emphasis on the most promising class of alloys, i.e., V-(4-5)Cr-(3-5)Ti containing 400-1000 wppm Si. Database on impact energy and ductile-brittle transition temperature (DBTT) has been established from Charpy impact tests on small laboratory as well as production-scale heats. DBTT is influenced most significantly by Cr contents and, to a lesser extent, by Ti contents of the alloys. When combined contents of Cr and Ti were {le}10 wt.%, V-Cr-Ti alloys exhibit excellent impact properties, i.e., DBTT<-200{degrees}C and upper shelf energies of {approx}120-140 J/cm{sup 2}. Impact properties of the production-scale heat of the U.S. reference alloy V-4Cr- 4Ti were as good as those of the laboratory-scale heats. Optimal impact properties of the reference alloy were obtained after annealing the as-rolled products at 1000{degrees}C-1050{degrees}C for 1-2 h in high-quality vacuum. 17 refs., 6 figs., 2 tabs.

  20. Reinforced Carbon-Carbon Subcomponent Flat Plate Impact Testing for Space Shuttle Orbiter Return to Flight

    NASA Technical Reports Server (NTRS)

    Melis, Matthew E.; Brand, Jeremy H.; Pereira, J. Michael; Revilock, Duane M.

    2007-01-01

    Following the tragedy of the Space Shuttle Columbia on February 1, 2003, a major effort commenced to develop a better understanding of debris impacts and their effect on the Space Shuttle subsystems. An initiative to develop and validate physics-based computer models to predict damage from such impacts was a fundamental component of this effort. To develop the models it was necessary to physically characterize Reinforced Carbon-Carbon (RCC) and various debris materials which could potentially shed on ascent and impact the Orbiter RCC leading edges. The validated models enabled the launch system community to use the impact analysis software LS DYNA to predict damage by potential and actual impact events on the Orbiter leading edge and nose cap thermal protection systems. Validation of the material models was done through a three-level approach: fundamental tests to obtain independent static and dynamic material model properties of materials of interest, sub-component impact tests to provide highly controlled impact test data for the correlation and validation of the models, and full-scale impact tests to establish the final level of confidence for the analysis methodology. This paper discusses the second level subcomponent test program in detail and its application to the LS DYNA model validation process. The level two testing consisted of over one hundred impact tests in the NASA Glenn Research Center Ballistic Impact Lab on 6 by 6 in. and 6 by 12 in. flat plates of RCC and evaluated three types of debris projectiles: BX 265 External Tank foam, ice, and PDL 1034 External Tank foam. These impact tests helped determine the level of damage generated in the RCC flat plates by each projectile. The information obtained from this testing validated the LS DYNA damage prediction models and provided a certain level of confidence to begin performing analysis for full-size RCC test articles for returning NASA to flight with STS 114 and beyond.

  1. Soft Soil Impact Testing and Simulation of Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Kellas, Sotiris

    2008-01-01

    In June 2007, a 38-ft/s vertical drop test of a 5-ft-diameter, 5-ft-long composite fuselage section that was retrofitted with a novel composite honeycomb Deployable Energy Absorber (DEA) was conducted onto unpacked sand. This test was one of a series of tests to evaluate the multi-terrain capabilities of the DEA and to generate test data for model validation. During the test, the DEA crushed approximately 6-in. and left craters in the sand of depths ranging from 7.5- to 9-in. A finite element model of the fuselage section with DEA was developed for execution in LS-DYNA, a commercial nonlinear explicit transient dynamic code. Pre-test predictions were generated in which the sand was represented initially as a crushable foam material MAT_CRUSHABLE_FOAM (Mat 63). Following the drop test, a series of hemispherical penetrometer tests were conducted to assist in soil characterization. The penetrometer weighed 20-lb and was instrumented with a tri-axial accelerometer. Drop tests were performed at 16-ft/s and crater depths were measured. The penetrometer drop tests were simulated as a means for developing a more representative soil model based on a soil and foam material definition MAT_SOIL_AND FOAM (Mat 5) in LS-DYNA. The model of the fuselage with DEA was reexecuted using the updated soil model and test-analysis correlations are presented.

  2. Materials Characterization Center meeting on impact testing of waste forms. Summary report

    SciTech Connect

    Merz, M.D.; Atteridge, D.; Dudder, G.

    1981-10-01

    A meeting was held on March 25-26, 1981 to discuss impact test methods for waste form materials to be used in nuclear waste repositories. The purpose of the meeting was to obtain guidance for the Materials Characterization Center (MCC) in preparing the MCC-10 Impact Test Method to be approved by the Materials Review Board. The meeting focused on two essential aspects of the test method, namely the mechanical process, or impact, used to effect rapid fracture of a waste form and the analysis technique(s) used to characterize particulates generated by the impact.

  3. Low velocity instrumented impact testing of four new damage tolerant carbon/epoxy composite systems

    NASA Technical Reports Server (NTRS)

    Lance, D. G.; Nettles, A. T.

    1990-01-01

    Low velocity drop weight instrumented impact testing was utilized to examine the damage resistance of four recently developed carbon fiber/epoxy resin systems. A fifth material, T300/934, for which a large data base exists, was also tested for comparison purposes. A 16-ply quasi-isotropic lay-up configuration was used for all the specimens. Force/absorbed energy-time plots were generated for each impact test. The specimens were cross-sectionally analyzed to record the damage corresponding to each impact energy level. Maximum force of impact versus impact energy plots were constructed to compare the various systems for impact damage resistance. Results show that the four new damage tolerant fiber/resin systems far outclassed the T300/934 material. The most damage tolerant material tested was the IM7/1962 fiber/resin system.

  4. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  5. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  6. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  7. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  8. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  9. Impact fuze testing at 3000 m/sec employing explosively accelerating plates

    SciTech Connect

    Gill, W.

    1981-01-01

    The Explosives Testing Division at Sandia has developed a method of simulating a re-entry vehicle impacting the ground. The purpose of the simulation is to evaluate different fusing concepts. The design and operation of this impact testing facility are described.

  10. 46 CFR 54.05-10 - Certification of material toughness tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Certification of material toughness tests. 54.05-10... PRESSURE VESSELS Toughness Tests § 54.05-10 Certification of material toughness tests. (a) Plate material... pipe or tube may certify such material by reporting the results of tests of one set of Charpy...

  11. 46 CFR 54.05-10 - Certification of material toughness tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Certification of material toughness tests. 54.05-10... PRESSURE VESSELS Toughness Tests § 54.05-10 Certification of material toughness tests. (a) Plate material... pipe or tube may certify such material by reporting the results of tests of one set of Charpy...

  12. 46 CFR 54.05-10 - Certification of material toughness tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Certification of material toughness tests. 54.05-10... PRESSURE VESSELS Toughness Tests § 54.05-10 Certification of material toughness tests. (a) Plate material... pipe or tube may certify such material by reporting the results of tests of one set of Charpy...

  13. 46 CFR 54.05-10 - Certification of material toughness tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Certification of material toughness tests. 54.05-10... PRESSURE VESSELS Toughness Tests § 54.05-10 Certification of material toughness tests. (a) Plate material... pipe or tube may certify such material by reporting the results of tests of one set of Charpy...

  14. 46 CFR 54.05-10 - Certification of material toughness tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Certification of material toughness tests. 54.05-10... PRESSURE VESSELS Toughness Tests § 54.05-10 Certification of material toughness tests. (a) Plate material... pipe or tube may certify such material by reporting the results of tests of one set of Charpy...

  15. The Adverse Impact of High Stakes Testing on Minority Students: Evidence from 100 Years of Test Data.

    ERIC Educational Resources Information Center

    Madaus, George F.; Clarke, Marguerite

    This paper examines four aspects of current high stakes testing that impact minority students and others traditionally underserved by American education. Data from research conducted at Boston College over 30 years highlight 4 issues: high stakes, high standards tests do not have a markedly positive effect on teaching and learning; high stakes…

  16. Is the psychological impact of genetic testing moderated by support and sharing of test results to family and friends?

    PubMed

    Lapointe, Julie; Dorval, Michel; Noguès, Catherine; Fabre, Roxane; Julian-Reynier, Claire

    2013-12-01

    Receiving the results of genetic tests for a breast and ovarian cancer susceptibility can be a stressful experience. Here we studied the effects of social support (SS) and the sharing of test results on the psychological impact of BRCA1/2 test result disclosure. We also compared carriers and non-carriers on sharing, SS and psychological impact. Five-hundred and twenty-two unaffected women were followed prospectively for 2 years after receiving their test results. Psychological impact was measured on the impact of event scale. Multivariate multi-level models were used, and all the analyses were stratified depending on mutation status (carriers vs non-carriers). Two weeks after receiving their BRCA1/2 results, carriers had shared their test results less frequently than non-carriers (p < 0.01). Sharing test results was not significantly associated with psychological impact. Availability of SS was significantly associated with better psychological adjustment across time among carriers (p < 0.01), but not among non-carriers. For female BRCA1/2 mutation carriers, the importance of SS should be stressed, and possible ways of enlisting people in their entourage for this purpose should be discussed in the context of clinical encounters.

  17. The Potential Impact of Not Being Able to Create Parallel Tests on Expected Classification Accuracy

    ERIC Educational Resources Information Center

    Wyse, Adam E.

    2011-01-01

    In many practical testing situations, alternate test forms from the same testing program are not strictly parallel to each other and instead the test forms exhibit small psychometric differences. This article investigates the potential practical impact that these small psychometric differences can have on expected classification accuracy. Ten…

  18. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.176... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  19. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  20. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.176... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  1. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  2. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  3. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  4. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.176... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  5. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  6. Hypervelocity Impact Testing of IM7/977-3 with Micro-Sized Particles

    NASA Technical Reports Server (NTRS)

    Smith, J. G.; Jegley, D. C.; Siochi, E. J.; Wells, B. K.

    2010-01-01

    Ground-based hypervelocity imapct testing was conducted on IM7/977-3 quasi-isotropic flat panels at normal incidence using micron-sized particles (i.e. less than or equal to 100 microns) of soda lime glass and olivine. Testing was performed at room temperature (RT) and 175 C with results from the 175 C test compared to those obtained at RT. Between 10 and 30 particles with velocities ranging from 5 to 13 km/s impacted each panel surface for each test temperature. Panels were ultrasonically scanned prior to and after impact testing to assess internal damage. Post-impact analysis included microscopic examination of the surface, determination of particle speed and location, and photomicroscopy for microcrack assessment. Internal damage was observed by ultrasonic inspection on panels impacted at 175 C, whereas damage for the RT impacted panels was confined to surface divets/craters as determined by microscopic analysis.

  7. Satellite Test of Radiation Impact on Ramtron 512K FRAM

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C.; Sayyah, Rana; Sims, W. Herb; Varnavas, Kosta A.; Ho, Fat D.

    2009-01-01

    The Memory Test Experiment is a space test of a ferroelectric memory device on a low Earth orbit satellite. The test consists of writing and reading data with a ferroelectric based memory device. Any errors are detected and are stored on board the satellite. The data is send to the ground through telemetry once a day. Analysis of the data can determine the kind of error that was found and will lead to a better understanding of the effects of space radiation on memory systems. The test will be one of the first flight demonstrations of ferroelectric memory in a near polar orbit which allows testing in a varied radiation environment. The memory devices being tested is a Ramtron Inc. 512K memory device. This paper details the goals and purpose of this experiment as well as the development process. The process for analyzing the data to gain the maximum understanding of the performance of the ferroelectric memory device is detailed.

  8. Testing Assumptions: The Impact of Two Study Abroad Program Models

    ERIC Educational Resources Information Center

    Norris, Emily Mohajeri; Dwyer, Mary M.

    2005-01-01

    There are many untested, long-held assumptions within the field of study abroad concerning the impact of program elements such as study duration, language of instruction, program models, and student housing choices. One assumption embraced within the field is that direct enrollment (or full immersion) programs are more effective at achieving a…

  9. Impact as a general cause of extinction: A feasibility test

    NASA Astrophysics Data System (ADS)

    Raup, David M.

    Large body impact has been implicated as the possible cause of several extinction events. This is entirely plausible if one accepts two propositions: (1) that impacts of large comets and asteroids produce environmental effects severe enough to cause significant species extinctions and (2) that the estimates of comet and asteroid flux for the Phanerozoic are approximately correct. A resonable next step is to investigate the possibility that impact could be a significant factor in the broader Phanerozoic extinction record, not limited merely to a few events of mass extinction. Monte Carlo simulation experiments based on existing flux estimates and reasonable predictions of the relationship between bolide diameter and extinction are discussed. The simulation results raise the serious possibility that large body impact may be a more pervasive factor in extinction than has been assumed heretofore. At the very least, the experiments show that the comet and asteroid flux estimates combined with a reasonable kill curve produces a reasonable extinction record, complete with occasional mass extinctions and the irregular, lower intensity extinctions commonly called background extinction.

  10. Impact as a general cause of extinction: A feasibility test

    NASA Technical Reports Server (NTRS)

    Raup, David M.

    1988-01-01

    Large body impact has been implicated as the possible cause of several extinction events. This is entirely plausible if one accepts two propositions: (1) that impacts of large comets and asteroids produce environmental effects severe enough to cause significant species extinctions and (2) that the estimates of comet and asteroid flux for the Phanerozoic are approximately correct. A resonable next step is to investigate the possibility that impact could be a significant factor in the broader Phanerozoic extinction record, not limited merely to a few events of mass extinction. Monte Carlo simulation experiments based on existing flux estimates and reasonable predictions of the relationship between bolide diameter and extinction are discussed. The simulation results raise the serious possibility that large body impact may be a more pervasive factor in extinction than has been assumed heretofore. At the very least, the experiments show that the comet and asteroid flux estimates combined with a reasonable kill curve produces a reasonable extinction record, complete with occasional mass extinctions and the irregular, lower intensity extinctions commonly called background extinction.

  11. Rationale for and dimensions of impact surfaces for biofidelity tests of different sizes of frontal and side impact dummies.

    PubMed

    Irwin, Annette L; Mertz, Harold J

    2010-11-01

    The biofidelity impact response corridors that were used to develop the Hybrid III family of dummies were established by scaling the various biofidelity corridors that were defined for the Hybrid III mid-size, adult male dummy. Scaling ratios for the responses of force, moment, acceleration, velocity, deflection, angle, stiffness and time were developed using dimensions and masses that were prescribed for the dummies. In addition, an elastic modulus ratio for bone was used to account for the differences between child and adult bone elastic properties. A similar method is being used by ISO/TC22/SC12/WG 5 to develop biofidelity guidelines for a family of side impact dummies based on scaling the biofidelity impact response corridors that are prescribed for WorldSID, a mid-size, adult male dummy. While the various biomechanical impact response requirements for the Hybrid III family of dummies and the WorldSID are documented in the literature, the scaling used to prescribe the dimensions of the impact surfaces that are used for the various biofidelity tests for various sizes of dummies are not documented. This paper describes the rationale for how these impact surfaces should be scaled, gives the scaling equations, and gives the dimensions of the impact surfaces that should be used for the various biofidelity tests of the different sizes of adult and child dummies. For future PMHS and human volunteer tests that are conducted to define impact biofidelity guidelines, it is recommended that the impact surfaces be scaled for the test subject size so that the data can be appropriately normalized to any size subject.

  12. The Impact of High Stakes Testing: The Australian Story

    ERIC Educational Resources Information Center

    Klenowski, Val; Wyatt-Smith, Claire

    2012-01-01

    High stakes testing in Australia was introduced in 2008 by way of the National Assessment Program--Literacy and Numeracy (NAPLAN). Currently, every year all students in Years 3, 5, 7 and 9 are assessed on the same days using national tests in Reading, Writing, Language Conventions (Spelling, Grammar and Punctuation) and Numeracy. In 2010 the…

  13. The Impact of Time Limits on Test Behaviors.

    ERIC Educational Resources Information Center

    Lin, Miao-Hsiang

    Specific questions addressed in this study include how time limits affect a test's construct and predictive validities, how time limits affect an examinee's time allocation and test performance, and whether the assumption about how examinees answer items is valid. Interactions involving an examinee's sex and age are studied. Two parallel forms of…

  14. Impact of Educational Level on Performance on Auditory Processing Tests

    PubMed Central

    Murphy, Cristina F. B.; Rabelo, Camila M.; Silagi, Marcela L.; Mansur, Letícia L.; Schochat, Eliane

    2016-01-01

    Research has demonstrated that a higher level of education is associated with better performance on cognitive tests among middle-aged and elderly people. However, the effects of education on auditory processing skills have not yet been evaluated. Previous demonstrations of sensory-cognitive interactions in the aging process indicate the potential importance of this topic. Therefore, the primary purpose of this study was to investigate the performance of middle-aged and elderly people with different levels of formal education on auditory processing tests. A total of 177 adults with no evidence of cognitive, psychological or neurological conditions took part in the research. The participants completed a series of auditory assessments, including dichotic digit, frequency pattern and speech-in-noise tests. A working memory test was also performed to investigate the extent to which auditory processing and cognitive performance were associated. The results demonstrated positive but weak correlations between years of schooling and performance on all of the tests applied. The factor “years of schooling” was also one of the best predictors of frequency pattern and speech-in-noise test performance. Additionally, performance on the working memory, frequency pattern and dichotic digit tests was also correlated, suggesting that the influence of educational level on auditory processing performance might be associated with the cognitive demand of the auditory processing tests rather than auditory sensory aspects itself. Longitudinal research is required to investigate the causal relationship between educational level and auditory processing skills. PMID:27013958

  15. Unintended and Unwelcome: The Local Impact of State Testing.

    ERIC Educational Resources Information Center

    Corbett, H. Dickson; Wilson, Bruce L.

    This paper summarizes the results of a study of the local consequences of implementing statewide minimum competency tests. For American education to be the best in the world, the use of statewide and nationwide standardized testing as a primary policy tool for stimulating reform must be discontinued. Second, school district responses to such…

  16. Testing and Resilience of the Impact Origin of the Moon

    NASA Technical Reports Server (NTRS)

    Righter, K.; Canup, R. M.

    2016-01-01

    The leading hypothesis for the origin of the Moon is the giant impact model, which grew out of the post-Apollo science community. The hypothesis was able to explain the high E-M system angular momentum, the small lunar core, and consistent with the idea that the early Moon melted substantially. The standard hypothesis requires that the Moon be made entirely from the impactor, strangely at odds with the nearly identical oxygen isotopic composition of the Earth and Moon, compositions that might be expected to be different if Moon came from a distinct impactor. Subsequent geochemical research has highlighted the similarity of both geochemical and isotopic composition of the Earth and Moon, and measured small but significant amounts of volatiles in lunar glassy materials, both of which are seemingly at odds with the standard giant impact model. Here we focus on key geochemical measurements and spacecraft observations that have prompted a healthy re-evaluation of the giant impact model, provide an overview of physical models that are either newly proposed or slightly revised from previous ideas, to explain the new datasets.

  17. IMPACT_S: integrated multiprogram platform to analyze and combine tests of selection.

    PubMed

    Maldonado, Emanuel; Sunagar, Kartik; Almeida, Daniela; Vasconcelos, Vitor; Antunes, Agostinho

    2014-01-01

    Among the major goals of research in evolutionary biology are the identification of genes targeted by natural selection and understanding how various regimes of evolution affect the fitness of an organism. In particular, adaptive evolution enables organisms to adapt to changing ecological factors such as diet, temperature, habitat, predatory pressures and prey abundance. An integrative approach is crucial for the identification of non-synonymous mutations that introduce radical changes in protein biochemistry and thus in turn influence the structure and function of proteins. Performing such analyses manually is often a time-consuming process, due to the large number of statistical files generated from multiple approaches, especially when assessing numerous taxa and/or large datasets. We present IMPACT_S, an easy-to-use Graphical User Interface (GUI) software, which rapidly and effectively integrates, filters and combines results from three widely used programs for assessing the influence of selection: Codeml (PAML package), Datamonkey and TreeSAAP. It enables the identification and tabulation of sites detected by these programs as evolving under the influence of positive, neutral and/or negative selection in protein-coding genes. IMPACT_S further facilitates the automatic mapping of these sites onto the three-dimensional structures of proteins. Other useful tools incorporated in IMPACT_S include Jmol, Archaeopteryx, Gnuplot, PhyML, a built-in Swiss-Model interface and a PDB downloader. The relevance and functionality of IMPACT_S is shown through a case study on the toxicoferan-reptilian Cysteine-rich Secretory Proteins (CRiSPs). IMPACT_S is a platform-independent software released under GPLv3 license, freely available online from http://impact-s.sourceforge.net.

  18. On the modeling of the Taylor cylinder impact test for orthotropic textured materials: Calculations and experiments

    SciTech Connect

    Maudlin, P.J.; Bingert, J.F.; House, J.W.

    1997-04-01

    Taylor impact tests using specimens cut from a rolled plate of Ta were conducted. The Ta was well-characterized in terms of flow stress and crystallographic texture. A piece-wise yield surface was interrogated from this orthotropic texture, and used in EPIC-95 3D simulations of the Taylor test. Good agreement was realized between the calculations and the post-test geometries in terms of major and minor side profiles and impact-interface footprints.

  19. Failure Behavior Characterization of Mo-Modified Ti Surface by Impact Test and Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Ma, Yong; Qin, Jianfeng; Zhang, Xiangyu; Lin, Naiming; Huang, Xiaobo; Tang, Bin

    2015-07-01

    Using the impact test and finite element simulation, the failure behavior of the Mo-modified layer on pure Ti was investigated. In the impact test, four loads of 100, 300, 500, and 700 N and 104 impacts were adopted. The three-dimensional residual impact dents were examined using an optical microscope (Olympus-DSX500i), indicating that the impact resistance of the Ti surface was improved. Two failure modes cohesive and wearing were elucidated by electron backscatter diffraction and energy-dispersive spectrometer performed in a field-emission scanning electron microscope. Through finite element forward analysis performed at a typical impact load of 300 N, stress-strain distributions in the Mo-modified Ti were quantitatively determined. In addition, the failure behavior of the Mo-modified layer was determined and an ideal failure model was proposed for high-load impact, based on the experimental and finite element forward analysis results.

  20. IXV Mock-Up Water Impact Test and Results Correlation

    NASA Astrophysics Data System (ADS)

    Ullio, R.; Becchio, V.; D'Amico, J.; Di Vita, G.

    2012-07-01

    In the frame of the ESA FLPP/IXV project one of the main goal is to validate the simulation methodology defined by TAS-I for the estimation of the maximum expected loads generated during splashdown event. Numerical results, obtained in different vehicle attitudes and landing conditions, were compared with experimental results from a reduced-scale drop test campaign, carried out making use of a rigid IXV vehicle scaled mock-up (1/4 of the IXV vehicle size). The test campaign was performed in the CNR-INSEAN (Istituto Nazionale per Studied Esperienze di Architettura Navale) facilities in Rome. In this paper firstly the engineering evaluation of the test results are discussed especially with respect to the selection of the best attitude candidate for landing. Then, the comparison of the test/analysis correlation activity is presented, and the related outcomes are evaluated in order to reduce the model factor uncertainty and enhance the derivation of the splashdown loads.

  1. Impact Testing of Aluminum 2024 and Titanium 6Al-4V for Material Model Development

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Revilock, Duane M.; Lerch, Bradley A.; Ruggeri, Charles R.

    2013-01-01

    One of the difficulties with developing and verifying accurate impact models is that parameters such as high strain rate material properties, failure modes, static properties, and impact test measurements are often obtained from a variety of different sources using different materials, with little control over consistency among the different sources. In addition there is often a lack of quantitative measurements in impact tests to which the models can be compared. To alleviate some of these problems, a project is underway to develop a consistent set of material property, impact test data and failure analysis for a variety of aircraft materials that can be used to develop improved impact failure and deformation models. This project is jointly funded by the NASA Glenn Research Center and the FAA William J. Hughes Technical Center. Unique features of this set of data are that all material property data and impact test data are obtained using identical material, the test methods and procedures are extensively documented and all of the raw data is available. Four parallel efforts are currently underway: Measurement of material deformation and failure response over a wide range of strain rates and temperatures and failure analysis of material property specimens and impact test articles conducted by The Ohio State University; development of improved numerical modeling techniques for deformation and failure conducted by The George Washington University; impact testing of flat panels and substructures conducted by NASA Glenn Research Center. This report describes impact testing which has been done on aluminum (Al) 2024 and titanium (Ti) 6Al-4vanadium (V) sheet and plate samples of different thicknesses and with different types of projectiles, one a regular cylinder and one with a more complex geometry incorporating features representative of a jet engine fan blade. Data from this testing will be used in validating material models developed under this program. The material

  2. Prognostic impact of stress testing in coronary artery disease

    SciTech Connect

    Severi, S.; Michelassi, C. )

    1991-05-01

    Observational data prospectively collected permit the examination of a complex set of decisions, including the decision not to perform any stress testing. Patients with or without previous myocardial infarction admitted for coronary evaluation and not submitted to any stress testing because of clinical reasons are at a higher risk for subsequent death. For prognostication, no test has been better validated than exercise electrocardiography: it can identify patients at low and high risk for future cardiac events among those without symptoms, with typical chest pain, and with previous myocardial infarction. In patients with triple-vessel disease, the results of exercise also allow those at low and high risk to be recognized. Both exercise radionuclide angiography and {sup 201}Tl scintigraphy (the latter in larger patient populations) have also demonstrated significant prognostic value on patients with or without previous myocardial infarction. Neither one has shown superiority to the other in prognostication. So far, they have been considered the only viable alternatives to exercise electrocardiography stress testing for diagnosis and prognostication. However, their costs limit their extensive application. Preliminary data suggest that intravenous dipyridamole echocardiography can be used for both diagnosis and prognostication of coronary artery disease; moreover, the prognostic information derived from dipyridamole echocardiography testing seems independent of and additive to that provided by exercise electrocardiography. Further prospective studies on larger patient populations are needed to better define the prognostic value of dipyridamole echocardiography testing.47 references.

  3. The role of the modified taylor impact test in dynamic material research

    NASA Astrophysics Data System (ADS)

    Bagusat, Frank; Rohr, Ingmar

    2015-09-01

    Dynamic material research with strain rates of more than 1000 1/s is experimentally very often done with a Split-Hopkinson Bar, Taylor impact tests or planar plate impact test investigations. At the Ernst-Mach-Institut (EMI), a variant of an inverted classical Taylor impact test is used by application of velocity interferometers of the VISAR type ("Modified Taylor Impact Test", MTT). The conduction of the experiments is similar to that of planar plate impact tests. The data reduction and derivation of dynamic material data can also be restricted to an analysis of the VISAR signal. Due to these properties, nearly each highly dynamic material characterization in our institute done by planar plate investigations is usually accompanied by MTT experiments. The extended possibilities and usefulness of a combined usage of these two highly dynamic characterization methods are explained. Recently, further developed MTT experiments with very small specimen sizes are presented. For the first time, Taylor impact and planar impact specimen can be used for which the load directions even in case of thin plate test material are identical and not perpendicular to each other. Consequences for testing construction elements are discussed.

  4. The evolution and impact of testing baghouse filter performance.

    PubMed

    Pham, Minh; Clark, Christina; Mckenna, John

    2012-08-01

    In 1995, the US. Environmental Protection Agency (EPA) initiated the Environmental Technology Verification (ETV) program for the purpose of generating both independent and credible performance verification of innovative technologies and helping to accelerate acceptance of these products into the marketplace to further benefit the environment and protect public health. The EPA has approved a testing protocol under this program to verify the performance of commercially available filtration products for pulse-jet baghouses in removingfine particulate matter (aerodynamic diameter<2.5 microm; PM2.5). This verification testing protocol was later used as a basis for the development of the American Society for Testing and Materials (ASTM) Method D6830-02 and the International Organization for Standardization (ISO) Method 11057. The South Coast Air Quality Management District (SCAQMD) in California and the EPA s Office of Air Quality Planning and Standards (OAQPS) highly encourage the use of ETV/ASTM-verified filtration media. This paper highlights the evolution of the standard test methods, the EPA's and SCAQMD's regulatory activities, the benefits of using verified filtration media, and the importance of including the filter performance testing in future consideration of baghouse permitting, baghouse operation and maintenance (O&M) plans, quality assurance/quality control (QA/QC), and bag monitoring plans.

  5. Normalization of Impact Energy by Laminate Thickness for Compression After Impact Testing

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.; Hromisin, S. M.

    2013-01-01

    The amount of impact energy used to damage a composite laminate is a critical parameter when assessing residual strength properties. The compression after impact (CAI) strength of impacted laminates is dependent upon how thick the laminate is and this has traditionally been accounted for by normalizing (dividing) the impact energy by the laminate's thickness. However, when comparing CAI strength values for a given lay-up sequence and fiber/resin system, dividing the impact energy by the specimen thickness has been noted by the author to give higher CAI strength values for thicker laminates. A study was thus undertaken to assess the comparability of CAI strength data by normalizing the impact energy by the specimen thickness raised to a power to account for the higher strength of thicker laminates. One set of data from the literature and two generated in this study were analyzed by dividing the impact energy by the specimen thickness to the 1, 1.5, 2, and 2.5 powers. Results show that as laminate thickness and damage severity decreased, the value which the laminate thickness needs to be raised to in order to yield more comparable CAI data increases.

  6. Impact of musical experience on the Seashore Rhythm Test.

    PubMed

    Karzmark, P

    2001-08-01

    The Seashore Rhythm Test (SRT) is sensitive to musical talent. The possibility that this reduces its clinical sensitivity in cognitively impaired persons with musical experience was investigated. Subjects were 101 referrals to the neuropsychology service of a large medical center. The results indicate that patients with a substantial amount of musical experience tend to perform normally on the SRT, even when overall performance on a neuropsychological test battery suggests cognitive impairment. This finding suggests caution in interpreting normal SRT results in those with a musical background.

  7. Capabilities of the Impact Testing Facility at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Finchum, Andy; Nehls, Mary; Young, Whitney; Gray, Perry; Suggs, Bart; Lowrey, Nikki M.

    2011-01-01

    The test and analysis capabilities of the Impact Testing Facility at NASA's Marshall Space Flight Center are described. Nine different gun systems accommodate a wide range of projectile and target sizes and shapes at velocities from subsonic through hypersonic, to accomplish a broad range of ballistic and hypervelocity impact tests. These gun systems include ballistic and microballistic gas and powder guns, a two-stage light gas gun, and specialty guns for weather encounter studies. The ITF "rain gun" is the only hydrometeor impact gun known to be in existence in the United States that can provide single impact performance data with known raindrop sizes. Simulation of high velocity impact is available using the Smooth Particle Hydrodynamic Code. The Impact Testing Facility provides testing, custom test configuration design and fabrication, and analytical services for NASA, the Department of Defense, academic institutions, international space agencies, and private industry in a secure facility located at Marshall Space Flight Center, on the US Army's Redstone Arsenal in Huntsville, Alabama. This facility performs tests that are subject to International Traffic in Arms Regulations (ITAR) and DoD secret classified restrictions as well as proprietary and unrestricted tests for civil space agencies, academic institutions, and commercial aerospace and defense companies and their suppliers.

  8. Elemental Water Impact Test: Phase 2 36-Inch Aluminum Tank Head

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2014-01-01

    Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. EWIT Phase 2 featured a 36-inch aluminum tank head. The tank head was outfitted with one accelerometer, twelve pressure transducers, three string potentiometers, and four strain gages. The tank head was dropped from heights of 1 foot and 2 feet. The focus of this report is the correlation of analytical models against test data. As a measure of prediction accuracy, peak responses from the baseline LS-DYNA model were compared to peak responses from the tests.

  9. Light airplane crash tests at impact velocities of 13 and 27 m/sec

    NASA Technical Reports Server (NTRS)

    Alfaro-Bou, E.; Vaughan, V. L., Jr.

    1977-01-01

    Two similar general aviation airplanes were crash tested at the Langley impact dynamics research facility at velocities of 13 and 27 m/sec. Other flight parameters were held constant. The facility, instrumentation, tests specimens, and test method are briefly described. Structural damage and accelerometer data are discussed.

  10. SRB/FWC water impact: Flexible body loads test

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Two technical areas were examined: evaluation of potential correction methods for spurious case strain outputs from the pressure transducers during the NSWC tests; and assessing procedures for modifying either the excitation function or the response function to account for hydroelastic effects.

  11. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, A.; Bergey, D.

    2014-02-01

    Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  12. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, Armin; Bergey, Daniel

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

  13. Permeability Testing of Impacted Composite Laminates for Use on Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    2001-01-01

    Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite, and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented, and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a nonlinear fashion for almost all the specimens tested.

  14. Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests

    SciTech Connect

    Niles, A M; Garcia, F; Greenwood, D W; Forbes, J W; Tarver, C M; Chidester, S K; Garza, R G; Swizter, L L

    2001-05-31

    The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and also be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 200-540 {micro}s after projectile impact, creating 0.39-2.00 kb peak shocks centered in PBX 9501 explosives discs and a 0.60 kb peak shock in a LX-04 disk. Steven Test modeling results, based on ignition and growth criteria, are presented for two PBX 9501 scenarios: one with projectile impact velocity just under threshold (51 m/s) and one with projectile impact velocity just over threshold (55 m/s). Modeling results are presented and compared to experimental data.

  15. Determination of Constitutive Model Constants from Cylinder Impact Tests

    DTIC Science & Technology

    1987-12-01

    HONEYWELL, INC./ARMAMENT SYSTEMS DIVISION) FOR NAVAL SURFACE WARFARE CENTER RESEARCH AND TECHNOLOGY DEPARTMENT DECEMBER 1988 Approved for public release...primary application is for higher strain rates, and the strain rate constant was therefore selected to give better correlation with the higher strain...to that of the test data. The new constants (C and C2) were obtained in conjunction with the previous values of C. and C4, as talen from Reference 2

  16. Small Scale Drop Tower Test for Practice Torpedo Impact Modelling

    DTIC Science & Technology

    2012-06-01

    Table E3. Tensile test results for the aluminium 6061 -T6 model hull plates. 2 coupons were cut with their length parallel to the long side of the...and without stiffeners and aluminium plate without stiffeners. A qualitative comparison of the results for the three model hull forms shows that...stiffeners tend to limit the extent of the dent, that aluminium plate has a greater elastic response than that of both stiffened and unstiffened steel

  17. Point of care testing: The impact of nanotechnology.

    PubMed

    Syedmoradi, Leila; Daneshpour, Maryam; Alvandipour, Mehrdad; Gomez, Frank A; Hajghassem, Hassan; Omidfar, Kobra

    2017-01-15

    Point-of-care (POC) diagnostic devices are integral in the health care system and particularly for the diagnosis and monitoring of diseases. POC testing has a variety of advantages including the ability to provide rapid and accurate results, ease of use, low cost, and little need for specialized equipment. One of the goals of POC testing is the development of a chip-based, miniaturized, portable, and self-containing system that allows for the assay of different analytes in complex samples. To achieve these goals, many researchers have focused on paper-based and printed electrode technologies as the material for fabricating POC diagnostic systems. These technologies are affordable, sensitive, user-friendly, rapid, and scalable for manufacturing. Moreover, the combination such devices with nanomaterials provide a path for the development of highly sensitive and selective biosensors for future generation POC tools. This review article discusses present technologies in on-site or at home POC diagnostic assays implemented in paper-based microfluidic and screen printing devices over the past decade as well as in the near future. In addition, recent advances in the application of nanomaterials such as gold nanoparticles, carbon nanotubes (CNTs), magnetic nanoparticles, and graphene in POC devices will be reviewed. The factors that limit POC testing to become real world products and future directions are also identified.

  18. Ballistic Impact Testing of Aluminum 2024 and Titanium 6Al-4V for Material Model Development

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Revilock, Duane M.; Ruggeri, Charles R.; Emmerling, William C.; Altobelli, Donald J.

    2012-01-01

    An experimental program is underway to develop a consistent set of material property and impact test data, and failure analysis, for a variety of materials that can be used to develop improved impact failure and deformation models. Unique features of this set of data are that all material property information and impact test results are obtained using identical materials, the test methods and procedures are extensively documented and all of the raw data is available. This report describes ballistic impact testing which has been conducted on aluminum (Al) 2024 and titanium (Ti) 6Al-4vanadium (V) sheet and plate samples of different thicknesses and with different types of projectiles, one a regular cylinder and one with a more complex geometry incorporating features representative of a jet engine fan blade.

  19. Technical Methods Report: Guidelines for Multiple Testing in Impact Evaluations. NCEE 2008-4018

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2008-01-01

    This report presents guidelines for addressing the multiple comparisons problem in impact evaluations in the education area. The problem occurs due to the large number of hypothesis tests that are typically conducted across outcomes and subgroups in these studies, which can lead to spurious statistically significant impact findings. The…

  20. Cycom 977-2 Composite Material: Impact Test Results (workshop presentation)

    NASA Technical Reports Server (NTRS)

    Engle, Carl; Herald, Stephen; Watkins, Casey

    2005-01-01

    Contents include the following: Ambient (13A) tests of Cycom 977-2 impact characteristics by the Brucenton and statistical method at MSFC and WSTF. Repeat (13A) tests of tested Cycom from phase I at MSFC to expended testing statistical database. Conduct high-pressure tests (13B) in liquid oxygen (LOX) and GOX at MSFC and WSTF to determine Cycom reaction characteristics and batch effect. Conduct expended ambient (13A) LOX test at MSFC and high-pressure (13B) testing to determine pressure effects in LOX. Expend 13B GOX database.

  1. Impact of testing styles and testing methods on achievement in general chemistry

    NASA Astrophysics Data System (ADS)

    Howell, Byron Edward

    2001-12-01

    This research conducted at a community college located in Northeast Texas studied testing style and testing methods in relation to achievement in general chemistry. Data was collected and examined from 212 participants. Of these, 143 completed both the MBTI and PEPS surveys. This provided 71 subjects designated as Sensor (S) types for the final phase of the study. The subjects were divided into two groups by performance on the PEPS. One group consisted of subjects that indicated a preference to communicate (test) using a formal/pencil-paper test format (linguistic testing style) and the other subjects indicated a preference to communicate (test) using a hands-on/movement test format (tactile testing style). All subjects were administered both a linguistic and tactile pretest prior to treatment and both a linguistic and tactile posttest after treatment. The data was analyzed using a 2 x 2 ANOVA for significant effects at the p < 0.05 level of confidence. The results indicated a significant interaction effect between the student testing style and test methods. While not conclusive, this study does indicate that the type of testing done in general chemistry may be favoring students with certain types of communication preferences (testing styles). Therefore students with many of the worker characteristics desired by the chemical industry may not be successful in general chemistry and choose a different career path.

  2. The Impact of Test Dimensionality, Common-Item Set Format, and Scale Linking Methods on Mixed-Format Test Equating

    ERIC Educational Resources Information Center

    Öztürk-Gübes, Nese; Kelecioglu, Hülya

    2016-01-01

    The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

  3. Particle Impact Ignition Test Data on a Stainless Steel Hand Valve

    NASA Technical Reports Server (NTRS)

    Peralta, Stephen

    2010-01-01

    This slide presentation reviews the particle impact ignition test of a stainless steel hand valve. The impact of particles is a real fire hazard with stainless steel hand valves, however 100 mg of particulate can be tolerated. Since it is unlikely that 100 mg of stainless steel contaminant particles can be simultaneously released into this type of valve in the WSTF configuration, this is acceptable and within statistical confidence as demonstrated by testing.

  4. Psychological impact of genetic testing for cancer susceptibility: an update of the literature.

    PubMed

    Meiser, Bettina

    2005-12-01

    This article presents an overview of the rapidly evolving body of literature on the psychological impact of genetic testing for hereditary breast/ovarian cancer susceptibility, hereditary non-polyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP). Uptake of genetic testing for BRCA1/2 and HNPCC-related mutations is more consistently related to psychological factors, rather than sociodemographic variables. Most studies on the psychological impact of genetic testing amongst individuals who have never been affected by cancer demonstrate that non-carriers derive significant psychological benefits from genetic testing, while no adverse effects have been observed amongst carriers. These benefits are more clear-cut for HNPCC, compared to hereditary breast/ovarian cancer, reflecting differences in risk management options. The few studies available on individuals affected with cancer indicate that the impact of genetic testing is mediated and amplified by their former experience of cancer. Future directions and challenges of research in this area are reviewed. In particular, more empirical data are needed on the broader impact of genetic testing on those with inconclusive results or results of uncertain significance. As genetic testing is becoming available for other types of familial cancer, additional investigations will be needed as there is evidence to suggest that the impact of genetic testing may be unique to each type of familial cancer.

  5. Developments in fracture mechanics test methods standardization; Proceedings of the Symposium, St. Louis, Mo., May 4, 1976

    NASA Technical Reports Server (NTRS)

    Brown, W. F., Jr.; Kaufman, J. G.

    1977-01-01

    Experience in plane-strain fracture toughness testing per ASTM Method E 399 is considered along with fracture toughness testing using the C-shaped specimen, an analysis of radially cracked ring segments subject to forces and couples, compliance calibration of specimens used in the R-curve practice, heavy-section fracture toughness screening specimen, and sharply notched cylindrical tension specimens for screening plane-strain fracture toughness. Attention is also given to an investigation of some problems in developing standards for precracked Charpy specimen strength ratios, fracture testing with surface crack specimens, and the estimation of plane strain fracture toughness values from slow bend precracked Charpy specimen strength ratios.

  6. Response of an Impact Test Apparatus for Fall Protective Headgear Testing Using a Hybrid-III Head/Neck Assembly

    PubMed Central

    Caccese, V.; Ferguson, J.; Lloyd, J.; Edgecomb, M.; Seidi, M.; Hajiaghamemar, M.

    2017-01-01

    A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus for use in the development of protective headgear designed to prevent injury due to falls. By including angular acceleration in the test protocol it becomes possible to assess and intentionally reduce this component of acceleration. Comparisons of standard and reduced durometer necks, various anvils, front, rear, and side drop orientations, and response data on performance of the apparatus are provided. Injury measures summarized for an unprotected drop include maximum linear and angular acceleration, head injury criteria (HIC), rotational injury criteria (RIC), and power rotational head injury criteria (PRHIC). Coefficient of variation for multiple drops ranged from 0.4 to 6.7% for linear acceleration. Angular acceleration recorded in a side drop orientation resulted in highest coefficient of variation of 16.3%. The drop test apparatus results in a reasonably repeatable test method that has potential to be used in studies of headgear designed to reduce head impact injury. PMID:28216804

  7. Strain rate effects for concrete and fiber-reinforced concrete subjected to impact loading. Final report, September 1982-August 1987

    SciTech Connect

    Shah, S.P.

    1987-10-01

    Despite it's extensive use, low tensile strength has been recognized as one of the major drawbacks of concrete. Although one has learned to avoid exposing concrete structures to adverse static tensile loads, these structures cannot be shielded from short duration dynamic tensile loads. Such loads originate from sources such as impact from missiles and projectiles, wind gusts, earthquakes and machine vibrations. In addition, modern computer-aided analysis and use of concrete for special structures such as reactor containment vessels, missile storage silos and fall-out shelters, has led to a growing interest in the cracking behavior of concrete. Experimental results indicate that the fracture strength and cracking behavior of concrete are affected by the rate of loading. To accurately predict the structural response under impact conditions, the knowledge of behavior of concrete at high rates of loading is essential. Using a two degree of freedom model guidelines were developed for designing an impact test setup, thus enabling one to conduct impact tests free of adverse inertial effects. Based on these guidelines, the author has developed an instrumented modified Charpy impact testing system. This experimental test setup was used to obtain basic information such as load-deflection relationship, fracture toughness, crack velocity (measured using Krak Gages), and load-strain history during an impact fracture event of plain concrete and SFRC.

  8. The psychological impact of predictive genetic testing for Huntington's disease: a systematic review of the literature.

    PubMed

    Crozier, S; Robertson, N; Dale, M

    2015-02-01

    Huntington's disease (HD) is a neurodegenerative genetic condition for which a predictive genetic test by mutation analysis has been available since 1993. However, whilst revealing the future presence of the disease, testing may have an adverse psychological impact given that the disease is progressive, incurable and ultimately fatal. This review seeks to systematically explore the psychological impact of genetic testing for individuals undergoing pre-symptomatic mutation analysis. Three databases (Medline, PsycInfo and Scopus) were interrogated for studies utilising standardised measures to assess psychological impact following predictive genetic testing for HD. From 100 papers initially identified, eight articles were eligible for inclusion. Psychological impact of predictive genetic testing was not found to be associated with test result. No detrimental effect of predictive genetic testing on non-carriers was found, although the process was not found to be psychologically neutral. Fluctuation in levels of distress was found over time for carriers and non-carriers alike. Methodological weaknesses of published literature were identified, notably the needs of individuals not requesting genetic testing, as well as inadequate support for individuals registering elevated distress and declining post-test follow-up. Further assessment of these vulnerable individuals is warranted to establish the extent and type of future psychological support.

  9. Multi-Terrain Impact Testing and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Lyle, Karen H.; Sparks, Chad E.; Sareen, Ashish K.

    2004-01-01

    Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.

  10. Multi-Terrain Impact Testing and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Lyle, Karen H.; Sparks, Chad E.; Sareen, Ashish K.

    2007-01-01

    Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.

  11. Impact of corrosion test container material in molten fluorides

    SciTech Connect

    Olson, Luke C.; Fuentes, Roderick E.; Martinez-Rodriguez, Michael J.; Ambrosek, James W.; Sridharan, Kumar; Anderson, Mark H.; Garcia-Diaz, Brenda L.; Gray, Joshua; Allen, Todd R.

    2015-10-15

    The effects of crucible material choice on alloy corrosion rates in immersion tests in molten LiF–NaF–KF (46.5–11.5-42 mol. %) salt held at 850 °C for 500 hrs are described. Four crucible materials were studied. Molten salt exposures of Incoloy-800H in graphite, Ni, Incoloy-800H, and pyrolytic boron nitride (PyBN) crucibles all led to weight-loss in the Incoloy-800H coupons. Alloy weight loss was ~30 times higher in the graphite and Ni crucibles in comparison to the Incoloy-800H and PyBN crucibles. It is hypothesized galvanic coupling between the alloy coupons and crucible materials contributed to the higher corrosion rates. Alloy salt immersion in graphite and Ni crucibles had similar weight-loss hypothesized to occur due to the rate limiting out diffusion of Cr in the alloys to the surface where it reacts with and dissolves into the molten salt, followed by the reduction of Cr from solution at the molten salt and graphite/Ni interfaces. As a result, both the graphite and the Ni crucibles provided sinks for the Cr, in the formation of a Ni–Cr alloy in the case of the Ni crucible, and Cr carbide in the case of the graphite crucible.

  12. Impact of corrosion test container material in molten fluorides

    DOE PAGES

    Olson, Luke C.; Fuentes, Roderick E.; Martinez-Rodriguez, Michael J.; ...

    2015-10-15

    The effects of crucible material choice on alloy corrosion rates in immersion tests in molten LiF–NaF–KF (46.5–11.5-42 mol. %) salt held at 850 °C for 500 hrs are described. Four crucible materials were studied. Molten salt exposures of Incoloy-800H in graphite, Ni, Incoloy-800H, and pyrolytic boron nitride (PyBN) crucibles all led to weight-loss in the Incoloy-800H coupons. Alloy weight loss was ~30 times higher in the graphite and Ni crucibles in comparison to the Incoloy-800H and PyBN crucibles. It is hypothesized galvanic coupling between the alloy coupons and crucible materials contributed to the higher corrosion rates. Alloy salt immersion inmore » graphite and Ni crucibles had similar weight-loss hypothesized to occur due to the rate limiting out diffusion of Cr in the alloys to the surface where it reacts with and dissolves into the molten salt, followed by the reduction of Cr from solution at the molten salt and graphite/Ni interfaces. As a result, both the graphite and the Ni crucibles provided sinks for the Cr, in the formation of a Ni–Cr alloy in the case of the Ni crucible, and Cr carbide in the case of the graphite crucible.« less

  13. Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

    PubMed

    Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers.

  14. The impact of equilibrium assumptions on tests of selection.

    PubMed

    Crisci, Jessica L; Poh, Yu-Ping; Mahajan, Shivani; Jensen, Jeffrey D

    2013-01-01

    With the increasing availability and quality of whole genome population data, various methodologies of population genetic inference are being utilized in order to identify and quantify recent population-level selective events. Though there has been a great proliferation of such methodology, the type-I and type-II error rates of many proposed statistics have not been well-described. Moreover, the performance of these statistics is often not evaluated for different biologically relevant scenarios (e.g., population size change, population structure), nor for the effect of differing data sizes (i.e., genomic vs. sub-genomic). The absence of the above information makes it difficult to evaluate newly available statistics relative to one another, and thus, difficult to choose the proper toolset for a given empirical analysis. Thus, we here describe and compare the performance of four widely used tests of selection: SweepFinder, SweeD, OmegaPlus, and iHS. In order to consider the above questions, we utilize simulated data spanning a variety of selection coefficients and beneficial mutation rates. We demonstrate that the LD-based OmegaPlus performs best in terms of power to reject the neutral model under both equilibrium and non-equilibrium conditions-an important result regarding the relative effectiveness of linkage disequilibrium relative to site frequency spectrum based statics. The results presented here ought to serve as a useful guide for future empirical studies, and provides a guide for statistical choice depending on the history of the population under consideration. Moreover, the parameter space investigated and the Type-I and Type-II error rates calculated, represent a natural benchmark by which future statistics may be assessed.

  15. The Testing Divide: New Research on the Intended and Unintended Impact of High-Stakes Testing.

    ERIC Educational Resources Information Center

    Amrein, Audrey L.; Berliner, David C.

    2003-01-01

    Found, based on data from 28 states, that there is scant evidence to support the proposition that high-stakes tests, including high-stakes high school graduation exams, increase student achievement. Also found that adoption of high-stakes testing policies leads to increased dropout rates, decreased graduation rates, and higher rates of younger…

  16. Psychological impact of genetic testing for Huntington's disease: an update of the literature.

    PubMed

    Meiser, B; Dunn, S

    2000-11-01

    Genetic testing has been available for Huntington's disease for longer than any other adult onset genetic disorder. The discovery of the genetic mutation causing Huntington's disease made possible the use of predictive testing to identify currently unaffected carriers. Concerns have been raised that predictive testing may lead to an increase in deaths by suicide among identified carriers, and these concerns set in motion research to assess the psychological impact of predictive testing for Huntington's disease. This review article provides an overview of the literature and draws implications for clinical practice. About 10%-20% of people at risk request testing when approached by registries or testing centres. Most of the evidence suggests that non-carriers and carriers differ significantly in terms of short term, but not long term, general psychological distress. Adjustment to results was found to depend more on psychological adjustment before testing than the testing result itself. Although risk factors for psychological sequelae have been identified, few adverse events have been described and no obvious contraindications for testing people at risk have been identified. The psychological impact of testing may depend on whether testing was based on linkage analysis or mutation detection. Cohorts enrolled in mutation detection programmes have higher levels of depression before and after testing, compared with people who sought genetic testing when linkage analysis was available. There is evidence that people who choose to be tested are psychologically selected for a favourable response to testing. The impact of testing on people in settings where less intensive counselling protocols and eligibility criteria are used is unknown, and genetic testing is therefore best offered as part of comprehensive specialist counselling.

  17. Impact of Panel Gene Testing for Hereditary Breast and Ovarian Cancer on Patients.

    PubMed

    Lumish, Heidi S; Steinfeld, Hallie; Koval, Carrie; Russo, Donna; Levinson, Elana; Wynn, Julia; Duong, James; Chung, Wendy K

    2017-03-29

    Recent advances in next generation sequencing have enabled panel gene testing, or simultaneous testing for mutations in multiple genes for a clinical condition. With more extensive and widespread genetic testing, there will be increased detection of genes with moderate penetrance without established clinical guidelines and of variants of uncertain significance (VUS), or genetic variants unknown to either be disease-causing or benign. This study surveyed 232 patients who underwent genetic counseling for hereditary breast and ovarian cancer to examine the impact of panel gene testing on psychological outcomes, patient understanding, and utilization of genetic information. The survey used standardized instruments including the Impact of Event Scale (IES), Multidimensional Impact of Cancer Risk Assessment (MICRA), Satisfaction with Decision Instrument (SWD), Ambiguity Tolerance Scale (AT-20), genetics knowledge, and utilization of genetic test results. Study results suggested that unaffected individuals with a family history of breast or ovarian cancer who received positive results were most significantly impacted by intrusive thoughts, avoidance, and distress. However, scores were also modestly elevated among unaffected patients with a family history of breast and ovarian cancer who received VUS, highlighting the impact of ambiguous results that are frequent among patients undergoing genetic testing with large panels of genes. Potential risk factors for increased genetic testing-specific distress in this study included younger age, black or African American race, Hispanic origin, lower education level, and lower genetic knowledge and highlight the need for developing strategies to provide effective counseling and education to these communities, particularly when genetic testing utilizes gene panels that more commonly return VUS. More detailed pre-test education and counseling may help patients appreciate the probability of various types of test results and how results

  18. The Impact of Mandated Statewide Testing on Teachers' Classroom Assessment and Instructional Practices.

    ERIC Educational Resources Information Center

    McMillan, James H.; Myran, Steve; Workman, Daryl

    The impact of the new Virginia statewide Standards of Learning (SOL) testing program on classroom instructional and assessment practices was studied through surveys before and after implementation of the testing program. The sample represented responses from 570 secondary school teachers (of mathematics, social studies, English, and science) and…

  19. An Exploration of the Impact of Accountability Testing on Teaching in Urban Elementary Classrooms

    ERIC Educational Resources Information Center

    Bisland, Beverly Milner

    2015-01-01

    This study explores accountability testing in the elementary schools of New York City with particular emphasis on the impact of a statewide social studies test on the value given to social studies instruction in comparison to other subjects. The attitudes of a group of elementary teachers are examined. Some of the teachers taught all subjects in…

  20. The Impact of High-Stakes Testing on Curriculum and Pedagogy: A Teacher Perspective from Australia

    ERIC Educational Resources Information Center

    Polesel, John; Rice, Suzanne; Dulfer, Nicole

    2014-01-01

    Debates continue about how high-stakes testing regimes influence schools at all levels: their impact on teaching practices, distribution of resources and curriculum provision, and whether they achieve the intended increases in student achievement in targeted areas. In 2008, the Australian government Introduced a national testing scheme, the"…

  1. The TOEFL Trump Card: An Investigation of Test Impact in an ESL Classroom

    ERIC Educational Resources Information Center

    Johnson, Karen E.; Jordan, Stefanie Rehn; Poehner, Matthew E.

    2005-01-01

    Much of the research on the effects of tests on foreign and second-language classrooms has examined the impact or washback effect that commercial/institutional language tests, such as the TOEFL, have on teachers' instructional practices (Hughes, 1998; Wall & Alderson, 1993). Using a case study methodology, this study uncovered the ways in…

  2. The Impact of Linking Distinct Achievement Test Scores on the Interpretation of Student Growth in Achievement

    ERIC Educational Resources Information Center

    Airola, Denise Tobin

    2011-01-01

    Changes to state tests impact the ability of State Education Agencies (SEAs) to monitor change in performance over time. The purpose of this study was to evaluate the Standardized Performance Growth Index (PGIz), a proposed statistical model for measuring change in student and school performance, across transitions in tests. The PGIz is a…

  3. The Impact of Time-Series Diagnostic Tests on the Writing Ability of Iranian EFL Learners

    ERIC Educational Resources Information Center

    Atashgahi, Bahareh Molazem

    2014-01-01

    This study aimed to show whether administering a battery of time-series diagnostic tests (screening) has any impact on Iranian EFL learners' writing ability. The study was conducted on the intermediate EFL learners at Islamic Azad University North Tehran branch. The researcher administered a homogenizing test in order to exclude the exceptional…

  4. An Approach for Addressing the Multiple Testing Problem in Social Policy Impact Evaluations

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2009-01-01

    In social policy evaluations, the multiple testing problem occurs due to the many hypothesis tests that are typically conducted across multiple outcomes and subgroups, which can lead to spurious impact findings. This article discusses a framework for addressing this problem that balances Types I and II errors. The framework involves specifying…

  5. The Risk of Adverse Impact in Selections Based on a Test with Known Effect Size

    ERIC Educational Resources Information Center

    De Corte, Wilfried; Lievens, Filip

    2005-01-01

    The authors derive the exact sampling distribution function of the adverse impact (AI) ratio for single-stage, top-down selections using tests with known effect sizes. Subsequently, it is shown how this distribution function can be used to determine the risk that a future selection decision on the basis of such tests will result in an outcome that…

  6. Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

    NASA Technical Reports Server (NTRS)

    Barbee, Brent W.; Hernandez, Sonia

    2012-01-01

    Earth has previously been struck with devastating force by near-Earth asteroids (NEAs) and will be struck again. Telescopic search programs aim to provide advance warning of such an impact, but no techniques or systems have yet been tested for deflecting an incoming NEA. To begin addressing this problem, we have analyzed the more than 8000 currently known NEAs to identify those that offer opportunities for safe and meaningful near-term tests of the proposed kinetic impact asteroid deflection technique. In this paper we present our methodology and results, including complete mission designs for the best kinetic impactor test mission opportunities.

  7. Nondestructive Evaluation Tests Performed on Space Shuttle Leading- Edge Materials Subjected to Impact

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Martin, Richard E.; Bodis, James R.

    2005-01-01

    In support of the space shuttle Return To Flight efforts at the NASA Glenn Research Center, a series of nondestructive evaluation (NDE) tests were performed on reinforced carbon/carbon (RCC) composite panels subjected to ballistic foam impact. The impact tests were conducted to refine and verify analytical models of an external tank foam strike on the space shuttle leading edge. The NDE tests were conducted to quantify the size and location of the resulting damage zone as well as to identify hidden damage.

  8. Impact testing of the H1224A shipping/storage container

    SciTech Connect

    Harding, D.C.; Bobbe, J.G.; Stenberg, D.R.; Arviso, M.

    1994-05-01

    H1224A weapons containers have been used for years by the Department of Energy and Department of Defense to transport and store W78 warhead midsections. Although designed to protect these midsections only in low-energy handling drop and impact accidents, a recent transportation risk assessment effort has identified a need to evaluate the container`s ability to protect weapons in higher-energy environments. Four impact tests were performed on H1224A containers with W78 Mod 6c mass mockup midsections inside, onto an essentially unyielding target. Dynamic acceleration and strain levels were recorded during the side-on and end-on impacts, each at 12.2 m/s (40 ft/s) and 38.1 m/s (125 ft/s). Measured peak accelerations experienced by the midsections during lower velocity impacts ranged from 250 to 600 Gs for the end-on impact and 350 to 600 Gs for the side-on impact. Measured peak accelerations of the midsections during the higher velocity impacts ranged from 3,000 to 10,000 Gs for the end-on impact and 8,000 to 10,000 Gs for the side-on impact. Deformations in the H1224A container ranged from minimal to severe buckling and weld tearing. At higher impact velocities, the H1224A container may not provide significant energy absorption for the re-entry vehicle midsection but can provide some confinement of potentially damaged components.

  9. Impact of Acoustic Standing Waves on Structural Responses: Reverberant Acoustic Testing (RAT) vs. Direct Field Acoustic Testing (DFAT)

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; Doty, Benjamin; Chang, Zensheu

    2012-01-01

    Loudspeakers have been used for acoustic qualification of spacecraft, reflectors, solar panels, and other acoustically responsive structures for more than a decade. Limited measurements from some of the recent speaker tests used to qualify flight hardware have indicated significant spatial variation of the acoustic field within the test volume. Also structural responses have been reported to differ when similar tests were performed using reverberant chambers. To address the impact of non-uniform acoustic field on structural responses, a series of acoustic tests were performed using a flat panel and a 3-ft cylinder exposed to the field controlled by speakers and repeated in a reverberant chamber. The speaker testing was performed using multi-input-single-output (MISO) and multi-input-multi-output (MIMO) control schemes with and without the test articles. In this paper the spatial variation of the acoustic field due to acoustic standing waves and their impacts on the structural responses in RAT and DFAT (both using MISO and MIMO controls for DFAT) are discussed in some detail.

  10. Methods for testing theory and evaluating impact in randomized field trials

    PubMed Central

    Brown, C. Hendricks; Wang, Wei; Kellam, Sheppard G.; Muthén, Bengt O.; Petras, Hanno; Toyinbo, Peter; Poduska, Jeanne; Ialongo, Nicholas; Wyman, Peter A.; Chamberlain, Patricia; Sloboda, Zili; MacKinnon, David P.; Windham, Amy

    2008-01-01

    Randomized field trials provide unique opportunities to examine the effectiveness of an intervention in real world settings and to test and extend both theory of etiology and theory of intervention. These trials are designed not only to test for overall intervention impact but also to examine how impact varies as a function of individual level characteristics, context, and across time. Examination of such variation in impact requires analytical methods that take into account the trial’s multiple nested structure and the evolving changes in outcomes over time. The models that we describe here merge multilevel modeling with growth modeling, allowing for variation in impact to be represented through discrete mixtures—growth mixture models—and nonparametric smooth functions—generalized additive mixed models. These methods are part of an emerging class of multilevel growth mixture models, and we illustrate these with models that examine overall impact and variation in impact. In this paper, we define intent-to-treat analyses in group-randomized multilevel field trials and discuss appropriate ways to identify, examine, and test for variation in impact without inflating the Type I error rate. We describe how to make causal inferences more robust to misspecification of covariates in such analyses and how to summarize and present these interactive intervention effects clearly. Practical strategies for reducing model complexity, checking model fit, and handling missing data are discussed using six randomized field trials to show how these methods may be used across trials randomized at different levels. PMID:18215473

  11. Methodology for mapping football head impact exposure to helmet pads for repeated loading testing.

    PubMed

    MacAlister, Anna; Young, Tyler; Daniel, Ray W; Rowson, Steven; Duma, Stefan M

    2014-01-01

    Football helmets have a lifespan of 10 years; however, no work has investigated how helmet padding properties change over time with use. The purpose of this study is to develop a methodology to control repeated pad loading and quantify changes in energy management. Head impact exposure data for 7-8 year old football players were used to find an average impact magnitude. NOCSAE-style drop tests were performed using an instrumented headform fitted with the same style helmet (Helmet A) used to collect population data to determine the compression depth and rate of the helmet padding during an average impact. Drops from the same height were then conducted for two other helmet types (Helmet B and Helmet C). For the average impact of ~15 g, the compression depth and rate of the pads from Helmet A were found to be 9.8 mm and 0.72 m/s respectively. The compression depths and rates for Helmets B and C were found to be 6.1 mm and 0.71 m/s and 10.7 mm and 0.69 m/s respectively. These parameters were utilized by a material testing system program to impact helmet padding. Repeated helmet pad loading can be tested using a material testing system for populations with known head impact exposure. The energy absorbing characteristics of the padding can be used to develop new safety regulations regarding the lifetime of helmets, affording better protection to athletes.

  12. Impact Toughness of Ultrafine-Grained Interstitial-Free Steel

    NASA Astrophysics Data System (ADS)

    Saray, Onur; Purcek, Gencaga; Karaman, Ibrahim; Maier, Hans J.

    2012-11-01

    Impact toughness of an ultrafine-grained (UFG) interstitial-free (IF) steel produced by equal-channel angular extrusion/pressing (ECAE/P) at room temperature was investigated using Charpy impact tests. The UFG IF steel shows an improved combination of strength and impact toughness compared with the corresponding coarse-grained (CG) one. The CG IF steel samples underwent a transition in fracture toughness values with decreasing temperature because of a sudden change in fracture mode from microvoid coalescence (ductile) to cleavage (brittle) fracture. Grain refinement down to the submicron (≈320 nm) levels increased the impact energies in the upper shelf and lower shelf regions, and it considerably decreased the ductile-to-brittle transition temperature (DBTT) from 233 K (-40 °C) for the CG steel to approximately 183 K (-90 °C) for the UFG steel. Also, the sudden drop in DBTT with a small transition range for the CG sample changed to a more gradual decrease in energy for the UFG sample. The improvement in toughness after UFG formation was attributed to the combined effects of grain refinement and delamination and/or separation in the heavily deformed microstructure. Although an obvious change from the ductile fracture by dimples to the brittle fracture by cleavage was recognized at 233 K (-40 °C) for the CG steel, no fully brittle fracture occurred even at 103 K (-170 °C) in the UFG steel.

  13. Test study on the performance of shielding configuration with stuffed layer under hypervelocity impact

    NASA Astrophysics Data System (ADS)

    Ke, Fa-wei; Huang, Jie; Wen, Xue-zhong; Ma, Zhao-xia; Liu, Sen

    2016-10-01

    In order to study the cracking and intercepting mechanism of stuffed layer configuration on the debris cloud and to develop stuffed layer configuration with better performance, the hypervelocity impact tests on shielding configurations with stuffed layer were carried out. Firstly, the hypervelocity impact tests on the shielding configuration with stuffed layer of 3 layer ceramic fibre and 3 layer aramid fibre were finished, the study results showed that the debris cloud generated by the aluminum sphere impacting bumper at the velocity of about 6.2 km/s would be racked and intercepted by the stuffed layer configuration efficiently when the ceramic fibre layers and aramid fibre layers were jointed together, however, the shielding performance would be declined when the ceramic fibre layers and aramid fibre layers were divided by some distance. The mechanism of stuffed layer racking and intercepting the debris cloud was analyzed according to the above test results. Secondly, based on the mechanism of the stuffed layer cracking and intercepint debirs cloud the hypervelocity impact tests on the following three stuffed layer structures with the equivalent areal density to the 1 mm-thick aluminum plate were also carried out to compare their performance of cracking and intercepting debris cloud. The mechanisms of stuffed layer racking and intercepting the debris cloud were validated by the test result. Thirdly, the influence of the stuffed layer position on the shielding performance was studied by the test, too. The test results would provide reference for the design of better performance shielding configuration with stuffed layer.

  14. Impact Testing and Analysis of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2002-01-01

    The fan case in a jet engine is a heavy structure because of its size and because of the requirement that it contain a blade released during engine operation. Composite materials offer the potential for reducing the weight of the case. Efficient design, test, and analysis methods are needed to efficiently evaluate the large number of potential composite materials and design concepts. The type of damage expected in a composite case under blade-out conditions was evaluated using a subscale test in which a glass/epoxy composite half-ring target was impacted with a wedge-shaped titanium projectile. Fiber shearing occurred near points of contact between the projectile and target. Delamination and tearing occurred on a larger scale. These damage modes were reproduced in a simpler test in which flat glass/epoxy composites were impacted with a blunt cylindrical projectile. A surface layer of ceramic eliminated fiber shear fracture but did not reduce delamination. Tests on 3D woven carbon/epoxy composites indicated that transverse reinforcement is effective in reducing delamination. A 91 cm (36 in.) diameter full-ring sub-component was proposed for larger scale testing of these and other composite concepts. Explicit, transient, finite element analyses indicated that a full-ring test is needed to simulate complete impact dynamics, but simpler tests using smaller ring sections are adequate when evaluation of initial impact damage is the primary concern.

  15. Psychosocial impact of repeat HIV-negative testing: a follow-up study.

    PubMed

    Ryder, Karen; Haubrich, Dennis J; Callà, Domenico; Myers, Ted; Burchell, Ann N; Calzavara, Liviana

    2005-12-01

    Continued sexual risk behavior following repeatedly testing HIV-negative in the Polaris HIV Seroconversion Study (Ontario, Canada) led to this follow-up study which identifies the impact of repeat negative testing among 64 men and women. Repeat HIV-negative testing frequently results in confusion as to what constitutes risk and occasionally to thoughts of HIV immunity. Narrative accounts include beliefs that monogamy constitutes safety from HIV, that psychosocial factors other than repeatedly testing negative leads to risk, and that sexual risk reduction is unsustainable. In conclusion, the repeat negative test experience for some neither clarifies risk behavior nor reinforces sustained risk reduction.

  16. Crash Testing and Simulation of a Cessna 172 Aircraft: Pitch Down Impact Onto Soft Soil

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2016-01-01

    During the summer of 2015, NASA Langley Research Center conducted three full-scale crash tests of Cessna 172 (C-172) aircraft at the NASA Langley Landing and Impact Research (LandIR) Facility. The first test represented a flare-to-stall emergency or hard landing onto a rigid surface. The second test, which is the focus of this paper, represented a controlled-flight-into-terrain (CFIT) with a nose-down pitch attitude of the aircraft, which impacted onto soft soil. The third test, also conducted onto soil, represented a CFIT with a nose-up pitch attitude of the aircraft, which resulted in a tail strike condition. These three crash tests were performed for the purpose of evaluating the performance of Emergency Locator Transmitters (ELTs) and to generate impact test data for model validation. LS-DYNA finite element models were generated to simulate the three test conditions. This paper describes the model development and presents test-analysis comparisons of acceleration and velocity time-histories, as well as a comparison of the time sequence of events for Test 2 onto soft soil.

  17. A systematic review of perceived risks, psychological and behavioral impacts of genetic testing.

    PubMed

    Heshka, Jodi T; Palleschi, Crystal; Howley, Heather; Wilson, Brenda; Wells, Philip S

    2008-01-01

    Genetic testing may enable early disease detection, targeted surveillance, and result in effective prevention strategies. Knowledge of genetic risk may also enable behavioral change. However, the impact of carrier status from the psychological, behavior, and perceived risk perspectives is not well understood. We conducted a systematic review to summarize the available literature on these elements. An extensive literature review was performed to identify studies that measured the perceived risk, psychological, and/or behavioral impacts of genetic testing on individuals. The search was not limited to specific diseases but excluded the impacts of testing for single gene disorders. A total of 35 articles and 30 studies were included. The studies evaluated hereditary nonpolyposis colorectal carcinoma, hereditary breast and ovarian cancer, and Alzheimer disease. For affective outcomes, the majority of the studies reported negative effects on carriers but these were short-lived. For behavioral outcomes, an increase in screening behavior of varying rates was demonstrated in carriers but the change in behaviors was less than expected. With respect to perceived risk, there were generally no differences between carriers and noncarriers by 12 months after genetic testing and over time risk perception decreased. Overall, predispositional genetic testing has no significant impact on psychological outcomes, little effect on behavior, and did not change perceived risk. It seems as though better patient education strategies are required. Our data would suggest better knowledge among carriers would not have significant psychological impacts and therefore, it is worth pursuing improved educational strategies.

  18. Determine ISS Soyuz Orbital Module Ballistic Limits for Steel Projectiles Hypervelocity Impact Testing

    NASA Technical Reports Server (NTRS)

    Lyons, Frankel

    2013-01-01

    A new orbital debris environment model (ORDEM 3.0) defines the density distribution of the debris environment in terms of the fraction of debris that are low-density (plastic), medium-density (aluminum) or high-density (steel) particles. This hypervelocity impact (HVI) program focused on assessing ballistic limits (BLs) for steel projectiles impacting the enhanced Soyuz Orbital Module (OM) micrometeoroid and orbital debris (MMOD) shield configuration. The ballistic limit was defined as the projectile size on the threshold of failure of the OM pressure shell as a function of impact speeds and angle. The enhanced OM shield configuration was first introduced with Soyuz 30S (launched in May 2012) to improve the MMOD protection of Soyuz vehicles docked to the International Space Station (ISS). This test program provides HVI data on U.S. materials similar in composition and density to the Russian materials for the enhanced Soyuz OM shield configuration of the vehicle. Data from this test program was used to update ballistic limit equations used in Soyuz OM penetration risk assessments. The objective of this hypervelocity impact test program was to determine the ballistic limit particle size for 440C stainless steel spherical projectiles on the Soyuz OM shielding at several impact conditions (velocity and angle combinations). This test report was prepared by NASA-JSC/ HVIT, upon completion of tests.

  19. Effect of Heat Treatment on the Microstructure and Properties of AerMet (trade name) 100 Steel

    DTIC Science & Technology

    1994-08-01

    205) 1725(250) 1965 (285) 0.2% Yield Strength, MPa (ks!) 1240 (180) 1550(225) 1725 (250) Charpy Impact Energy, Joule (ftilb) 81 (60) 88(65) 40 (30...frac- ture toughness and Charpy impact energy for four different heat treatments. Longitudinal tensile tests were conducted according to ASTM... Charpy impact energy was measured according to ASrM Standard E-23. 3 1 At least two speci- mens were used for each test and material condition evaluated

  20. Oblique impact sensitivity of explosives: The skid test the snatch friction sensitivity test. Quarterly report, April--June 1964

    SciTech Connect

    Akst, I.B.; Washburn, B.M.; Rigdon, J.K.

    1997-09-01

    The oblique impact sensitivity of UK-UK-simulated HMX in 85 to 90% formulation with Viton is not enough lower, if any, to encourage richer formulations or change to Bridgewater processes for this reason alone. Fifty-pound cyclotol 75/25 hemispheres gave moderate reactions (No. 4) as low as 3.5 foot (14{degrees}); lower tests have not been performed yet. {open_quotes}Reduced-H.E.{close_quotes} pieces of PBX 9404, 2, 3, 4, and 5 inches thick, respectively, were tested at 1.75 foot (14{degrees}) resulting in a 6 reaction for the 5 inches thick piece while the remaining three pieces gave 0 reactions.

  1. Supplemental final environmental impact statement for advanced solid rocket motor testing at Stennis Space Center

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Since the Final Environmental Impact Statement (FEIS) and Record of Decision on the FEIS describing the potential impacts to human health and the environment associated with the program, three factors have caused NASA to initiate additional studies regarding these issues. These factors are: (1) The U.S. Army Corps of Engineers and the Environmental Protection Agency (EPA) agreed to use the same comprehensive procedures to identify and delineate wetlands; (2) EPA has given NASA further guidance on how best to simulate the exhaust plume from the Advanced Solid Rocket Motor (ASRM) testing through computer modeling, enabling more realistic analysis of emission impacts; and (3) public concerns have been raised concerning short and long term impacts on human health and the environment from ASRM testing.

  2. Evaluating the Impact of Test Accommodations on Test Scores of LEP Students & Non-LEP Students.

    ERIC Educational Resources Information Center

    Hafner, Anne L.

    Using a quasi-experimental analysis of variance (ANOVA) design, this project examined the effects of the use of accommodations with students of limited English proficiency (LEP) and non-LEP students and whether the use of accommodations affected the validity of test score interpretations. Major accommodations examined were extra time, and extra…

  3. Influence of stress concentrator shape and testing temperature on impact fracture regularities of pipeline steel

    NASA Astrophysics Data System (ADS)

    Vlasov, I. V.; Panin, S. V.; Maruschak, P. O.; Moiseenko, D. D.; Berto, F.

    2017-02-01

    The structure and impact toughness of the pipeline 17Mn1Si steel have been studied. The main attention was paid to the analysis of various conditions of stress concentration under dynamic loadings. The process of strain localization with increasing stress state stiffness at the tip of the concentrator with decreasing testing temperature was investigated. Impact loading diagrams for specimens with various stress concentrator shapes were registered and analyzed.

  4. FTIR study of hydrogen bonds in coal under drop weight impact testing.

    PubMed

    Li, Cheng-Wu; Wang, Jin-Gui; Xie, Bei-Jing; Dong, Li-Hui; Sun, Ying-Feng; Cao, Xu

    2014-11-01

    There are many hydrogen bonds in coal, which affect the chemical structure and properties of coal. FTIR has been applied to the characterization study of the hydrogen bonds of Dongpang coals, which were under drop weight impact. There exists five kinds of hydrogen bonds in the coal: free OH groups, OH...π, OH...OH, cyclic OH tetramers and OH...N. Absorption strength of intermolecular hydrogen bonds markedly declined after impact. Free OH groups mechanical-power chemical reacted in drop weight impact testing. The infrared spectrum were curve-resolved into their component bands. The absorption strength of various hydrogen bonds decreased with the increase of impact energy, but the trend was slowing. By statistical relationship between then, we find then complying with power function relationship. By comparing the exponents of fitted equations, we concluded that failure sensitivity sequence of hydrogen bonds to the impact: free OH groups > cyclic OH tetramers > OH...N > OH...π > OH...OH.

  5. Simulated Waste Testing Of Glycolate Impacts On The 2H-Evaporator System

    SciTech Connect

    Martino, C. J.

    2013-08-13

    Glycolic acid is being studied as a total or partial replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste tank farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the tank farm were addressed via a literature review, but several outstanding issues remained. This report documents the non-radioactive simulant tests impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The testing for which non-radioactive simulants could be used involved the following: the partitioning of glycolate into the evaporator condensate, the impacts of glycolate on metal solubility, and the impacts of glycolate on the formation and dissolution of sodium aluminosilicate scale within the evaporator. The following are among the conclusions from this work: Evaporator condensate did not contain appreciable amounts of glycolate anion. Of all tests, the highest glycolate concentration in the evaporator condensate was 0.38 mg/L. A significant portion of the tests had glycolate concentration in the condensate at less than the limit of quantification (0.1 mg/L). At ambient conditions, evaporator testing did not show significant effects of glycolate on the soluble components in the evaporator concentrates. Testing with sodalite solids and silicon containing solutions did not show significant effects of glycolate on sodium aluminosilicate formation or dissolution.

  6. Ductile Damage Prediction in Taylor Impact Cylinder Test Using CDM Approach

    NASA Astrophysics Data System (ADS)

    Ruggiero, A.; Bonora, N.

    2004-07-01

    Taylor cylinder impact test has been initially proposed as a potential testing technique to measure dynamic effect on material yield strength. Today, this technique represents an interesting benchmark case for constitutive and damage model performance verification. In this study, an extensive numerical investigation, using both finite element code and Lagrangian hydro-code, has been performed on standard Taylor impact cylinder configuration and Rod-on-Rod (ROR) test in OFHC and OFE copper. Here, material strength has been modeled using Johnson and Cook formulation which accounts both strain rate and temperature material sensibility. Ductile damage has been modeled using an advanced continuum damage mechanics model, as proposed by Bonora, which accounts for stress triaxiality effects on ductility, stress history at material point and where only a limited number of parameters is required. For both the test configuration investigated, both final calculated post test shape and damage pattern have been compared with experimental data available in literature.

  7. Guidelines for conducting impact tests on shipping packages for radioactive material

    SciTech Connect

    Mok, G.C.; Carlson, R.W.; Lu, S.C.; Fischer, L.E.

    1995-09-01

    Federal regulation (10 CFR Part 71) specifies a number of impact conditions (free-drop, penetration, and puncture), under which a package for the transport of radioactive materials must be tested or evaluated to demonstrate compliance with the regulation. This report is a comprehensive guide to the planning and execution of these impact tests. The report identifies the required considerations for both the design, pre-, and post-test inspections of the test model and the measurement, recording, analysis, and reporting of the test data. The report also presents reasons for the requirements, identifies the major difficulties in meeting these requirements, and suggests possible methods to overcome the difficulties. Discussed in substantial detail is the use of scale models and instrumented measurements.

  8. Mechanical impact tests of materials in oxygen effects of contamination. [Teflon, stainless steel, and aluminum

    NASA Technical Reports Server (NTRS)

    Ordin, P. M.

    1980-01-01

    The effect of contaminants on the mechanical impact sensitivity of Teflon, stainless steel, and aluminum in a high-pressure oxygen environment was investigated. Uncontaminated Teflon did not ignite under the test conditions. The liquid contaminants - cutting oil, motor lubricating oil, and toolmaker dye - caused Teflon to ignite. Raising the temperature lowered the impact energy required for ignition. Stainless steel was insensitive to ignition under the test conditions with the contaminants used. Aluminum appeared to react without contaminants under certain test conditions; however, contamination with cutting oil, motor lubricating oil, and toolmakers dye increased the sensitivity of aluminum to mechanical impact. The grit contaminants silicon dioxide and copper powder did not conclusively affect the sensitivity of aluminum.

  9. Railgun Application for High Energy Impact Testing of Nano-Reinforced Kevlar-Based Composite Materials

    NASA Astrophysics Data System (ADS)

    Micheli, D.; Vricella, A.; Pastore, R.; Morles, R. B.; Marchetti, M.

    2013-08-01

    An advanced electromagnetic accelerator, called railgun, has been assembled and tuned in order to perform high energy impact test on layered structures. Different types of layered composite materials have been manufactured and characterized in terms of energy absorbing capability upon impact of metallic bullets fired at high velocity. The composite materials under testing are manufactured by integrating several layers of Kevlar fabric and carbon fiber ply within a polymeric matrix reinforced by carbon nanotubes at 1% of weight percentage. The experimental results show that the railgun-device is a good candidate to perform impact testing of materials in the space debris energy range, and that carbon nanotubes may enhance, when suitably coupled to the composite's matrix, the excellent antiballistic properties of the Kevlar fabrics.

  10. Comparison of Hybrid III child test dummies to pediatric PMHS in blunt thoracic impact response.

    PubMed

    Parent, D P; Crandall, J R; Bolton, J R; Bass, C R; Ouyang, J; Lau, S H

    2010-08-01

    The limited availability of pediatric biomechanical impact response data presents a significant challenge to the development of child dummies. In the absence of these data, the development of the current generation of child dummies has been driven by scaling of the biomechanical response requirements of the existing adult test dummies. Recently published pediatric blunt thoracic impact response data provide a unique opportunity to evaluate the efficacy of these scaling methodologies. However, the published data include several processing anomalies and nonphysical features. These features are corrected by minimizing instrumentation and processing error to improve the fidelity of the individual force-deflection responses. Using these data, biomechanical impact response corridors are calculated for a 3-year-old child and a 6-year-old child. These calculated corridors differ from both the originally published postmortem human subject (PMHS) corridors and the impact response requirements of the current child dummies. Furthermore, the response of the Hybrid III 3-year-old test dummy in the same impact condition shows a similar deflection but a significantly higher force than the 3-year-old corridor. The response of the Hybrid III 6-year-old dummy, on the other hand, correlates well with the calculated 6-year-old corridor. The newly developed 3-year-old and 6-year-old blunt thoracic impact response corridors can be used to define data-driven impact response requirements as an alternative to scaling-driven requirements.

  11. Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Billings, Marcus D.

    2001-01-01

    The nonlinear finite element program MSC.Dytran was used to predict the impact pulse for (he drop test of an energy absorbing cellular structure. This pre-test simulation was performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. In addition, a goal of the simulation was to bound the acceleration pulse produced and delivered to the simulated space cargo container. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the enter of the EEV's cellular structure. The material models and failure criteria were varied to determine their effect on the resulting acceleration pulse. Pre-test analytical predictions using MSC.Dytran were compared with the test results obtained from impact test #4 using bungee accelerator located at the NASA Langley Research Center Impact Dynamics Research Facility. The material model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAMI model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for drop test #4.

  12. Safety assessment characteristics of pedestrian legform impactors in vehicle-front impact tests.

    PubMed

    Matsui, Yasuhiro

    2014-12-01

    This study investigated the characteristics of safety assessment results of front-area vehicle impact tests carried out using the Transport Research Laboratory (TRL) legform impactor and a flexible legform impactor (FLEX legform impactor). Different types of vehicles (sedan, sport utility vehicle, high-roof K-car, and light cargo van) were examined. The impact locations in the study were the center of the bumper and an extremely stiff structure of the bumper (i.e., in front of the side member) of each tested vehicle. The measured injury criteria were normalized by injury assessment reference values of each legform impactor. The test results for center and side-member impacts indicated that there were no significant differences in ligament injury assessments derived from the normalized knee ligament injury measures between the TRL legform impactor and the FLEX legform impactor. Evaluations made using the TRL legform impactor and the FLEX legform impactor are thus similar in the vehicle safety investigation for knee ligament injury. Vehicle-center impact test results revealed that the tibia fracture assessments derived from the normalized tibia fracture measures did not significantly differ between the TRL legform impactor and the FLEX legform impactor. However, for an impact against an extremely stiff structure, there was a difference in the tibia fracture assessment between the FLEX legform impactor and the TRL legform impactor owing to their different sensor types.

  13. Quasi-Uniform High Speed Foam Crush Testing Using a Guided Drop Mass Impact

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E. (Technical Monitor); Kellas, Sotiris

    2004-01-01

    A relatively simple method for measuring the dynamic crush response of foam materials at various loading rates is described. The method utilizes a drop mass impact configuration with mass and impact velocity selected such that the crush speed remains approximately uniform during the entire sample crushing event. Instrumentation, data acquisition, and data processing techniques are presented, and limitations of the test method are discussed. The objective of the test method is to produce input data for dynamic finite element modeling involving crash and energy absorption characteristics of foam materials.

  14. The Impact of an Electronic Medical Record on Repeat Laboratory Test Ordering Across Four Australian Hospitals.

    PubMed

    Georgiou, Andrew; Vecellio, Elia; Li, Ling; Westbrook, Johanna I

    2015-01-01

    In this study we examined the impact of an Electronic Medical Record (EMR) on repeat test rates (i.e., the same test ordered within a specified window of time) for a commonly ordered set of laboratory tests; Electrolytes, Urea, Creatinine [EUC], Full Blood Counts [FBC] and Liver Function Tests [LFT]. The results point to the potential that timely, evidence-based electronic decision support features can have on the efficiency and effectiveness of the pathology laboratory process and its contribution to quality patient care.

  15. Ecological impacts of invasive alien species along temperature gradients: testing the role of environmental matching.

    PubMed

    Iacarella, Josephine C; Dick, Jaimie T A; Alexander, Mhairi E; Ricciardi, Anthony

    2015-04-01

    Invasive alien species (IAS) can cause substantive ecological impacts, and the role of temperature in mediating these impacts may become increasingly significant in a changing climate. Habitat conditions and physiological optima offer predictive information for IAS impacts in novel environments. Here, using meta-analysis and laboratory experiments, we tested the hypothesis that the impacts of IAS in the field are inversely correlated with the difference in their ambient and optimal temperatures. A meta-analysis of 29 studies of consumptive impacts of IAS in inland waters revealed that the impacts of fishes and crustaceans are higher at temperatures that more closely match their thermal growth optima. In particular, the maximum impact potential was constrained by increased differences between ambient and optimal temperatures, as indicated by the steeper slope of a quantile regression on the upper 25th percentile of impact data compared to that of a weighted linear regression on all data with measured variances. We complemented this study with an experimental analysis of the functional response (the relationship between predation rate and prey supply) of two invasive predators (freshwater mysid shrimp, Hemimysis anomala and Mysis diluviana) across. relevant temperature gradients; both of these species have previously been found to exert strong community-level impacts that are corroborated by their functional responses to different prey items. The functional response experiments showed that maximum feeding rates of H. anomala and M. diluviana have distinct peaks near their respective thermal optima. Although variation in impacts may be caused by numerous abiotic or biotic habitat characteristics, both our analyses point to temperature as a key mediator of IAS impact levels in inland waters and suggest that IAS management should prioritize habitats in the invaded range that more closely match the thermal optima of targeted invaders.

  16. Impact Analyses and Tests of Metal Cask Considering Aircraft Engine Crash - 12308

    SciTech Connect

    Lee, Sanghoon; Choi, Woo-Seok; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog

    2012-07-01

    The structural integrity of a dual purpose metal cask currently under development by the Korea Radioactive Waste Management Cooperation (KRMC) is evaluated through analyses and tests under a high-speed missile impact considering the targeted aircraft crash conditions. The impact conditions were carefully chosen through a survey on accident cases and recommendations from the literature. The missile impact velocity was set at 150 m/s, and two impact orientations were considered. A simplified missile simulating a commercial aircraft engine is designed from an impact load history curve provided in the literature. In the analyses, the focus is on the evaluation of the containment boundary integrity of the metal cask. The analyses results are compared with the results of tests using a 1/3 scale model. The results show very good agreements, and the procedure and methodology adopted in the structural analyses are validated. While the integrity of the cask is maintained in one evaluation where the missile impacts the top side of the free standing cask, the containment boundary is breached in another case in which the missile impacts the center of the cask lid in a perpendicular orientation. A safety assessment using a numerical simulation of an aircraft engine crash into spent nuclear fuel storage systems is performed. A commercially available explicit finite element code is utilized for the dynamic simulation, and the strain rate effect is included in the modeling of the materials used in the target system and missile. The simulation results show very good agreement with the test results. It is noted that this is the first test considering an aircraft crash in Korea. (authors)

  17. A unified theory of impact crises and mass extinctions: quantitative tests.

    PubMed

    Rampino, M R; Haggerty, B M; Pagano, T C

    1997-05-30

    Several quantitative tests of a general hypothesis linking impacts of large asteroids and comets with mass extinctions of life are possible based on astronomical data, impact dynamics, and geological information. The waiting times of large-body impacts on the Earth derived from the flux of Earth-crossing asteroids and comets, and the estimated size of impacts capable of causing, large-scale environmental disasters, predict the impacts of objects > or = 5 km in diameter (> or = 10(7) Mt TNT equivalent) could be sufficient to explain the record of approximately 25 extinction pulses in the last 540 Myr, with the 5 recorded major mass extinctions related to impacts of the largest objects of > or = 10 km in diameter (> or = 10(8) Mt events). Smaller impacts (approximately 10(6) Mt), with significant regional environmental effects, could be responsible for the lesser boundaries in the geologic record. Tests of the "kill curve" relationship for impact-induced extinctions based on new data on extinction intensities, and several well-dated large impact craters, also suggest that major mass extinctions require large impacts, and that a step in the kill curve may exist at impacts that produce craters of approximately 100 km diameter, smaller impacts being capable of only relatively weak extinction pulses. Single impact craters less than approximately 60 km in diameter should not be associated with detectable global extinction pulses (although they may explain stage and zone boundaries marked by lesser faunal turnover), but multiple impacts in that size range may produce significant stepped extinction pulses. Statistical tests of the last occurrences of species at mass-extinction boundaries are generally consistent with predictions for abrupt or stepped extinctions, and several boundaries are known to show "catastrophic" signatures of environmental disasters and biomass crash, impoverished postextinction fauna and flora dominated by stress-tolerant and opportunistic species

  18. A small-scale test for fiber release from carbon composites. [pyrolysis and impact

    NASA Technical Reports Server (NTRS)

    Gilwee, W. J., Jr.; Fish, R. H.

    1980-01-01

    A test method was developed to determine relative fiber loss from pyrolyzed composites with different resins and fiber construction. Eleven composites consisting of woven and unwoven carbon fiber reinforcement and different resins were subjected to the burn and impact test device. The composites made with undirectional tape had higher fiber loss than those with woven fabric. Also, the fiber loss was inversely proportional to the char yield of the resin.

  19. Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model

    NASA Technical Reports Server (NTRS)

    Sakuraba, K.; Tsuruda, Y.; Hanada, T.; Liou, J.-C.; Akahoshi, Y.

    2007-01-01

    This paper summarizes two new satellite impact tests conducted in order to investigate on the outcome of low- and hyper-velocity impacts on two identical target satellites. The first experiment was performed at a low velocity of 1.5 km/s using a 40-gram aluminum alloy sphere, whereas the second experiment was performed at a hyper-velocity of 4.4 km/s using a 4-gram aluminum alloy sphere by two-stage light gas gun in Kyushu Institute of Technology. To date, approximately 1,500 fragments from each impact test have been collected for detailed analysis. Each piece was analyzed based on the method used in the NASA Standard Breakup Model 2000 revision. The detailed analysis will conclude: 1) the similarity in mass distribution of fragments between low and hyper-velocity impacts encourages the development of a general-purpose distribution model applicable for a wide impact velocity range, and 2) the difference in area-to-mass ratio distribution between the impact experiments and the NASA standard breakup model suggests to describe the area-to-mass ratio by a bi-normal distribution.

  20. Putting social impact assessment to the test as a method for implementing responsible tourism practice

    SciTech Connect

    McCombes, Lucy; Vanclay, Frank; Evers, Yvette

    2015-11-15

    The discourse on the social impacts of tourism needs to shift from the current descriptive critique of tourism to considering what can be done in actual practice to embed the management of tourism's social impacts into the existing planning, product development and operational processes of tourism businesses. A pragmatic approach for designing research methodologies, social management systems and initial actions, which is shaped by the real world operational constraints and existing systems used in the tourism industry, is needed. Our pilot study with a small Bulgarian travel company put social impact assessment (SIA) to the test to see if it could provide this desired approach and assist in implementing responsible tourism development practice, especially in small tourism businesses. Our findings showed that our adapted SIA method has value as a practical method for embedding a responsible tourism approach. While there were some challenges, SIA proved to be effective in assisting the staff of our test case tourism business to better understand their social impacts on their local communities and to identify actions to take. - Highlights: • Pragmatic approach is needed for the responsible management of social impacts of tourism. • Our adapted Social impact Assessment (SIA) method has value as a practical method. • SIA can be embedded into tourism businesses existing ‘ways of doing things’. • We identified challenges and ways to improve our method to better suit small tourism business context.

  1. Dynamic impact testing of hedgehog spines using a dual-arm crash pendulum.

    PubMed

    Swift, Nathan B; Hsiung, Bor-Kai; Kennedy, Emily B; Tan, Kwek-Tze

    2016-08-01

    Hedgehog spines are a potential model for impact resistant structures and material. While previous studies have examined static mechanical properties of individual spines, actual collision tests on spines analogous to those observed in the wild have not previously been investigated. In this study, samples of roughly 130 keratin spines were mounted vertically in thin substrates to mimic the natural spine layout on hedgehogs. A weighted crash pendulum was employed to induce and measure the effects of repeated collisions against samples, with the aim to evaluate the influence of various parameters including humidity effect, impact energy, and substrate hardness. Results reveal that softer samples-due to humidity conditioning and/or substrate material used-exhibit greater durability over multiple impacts, while the more rigid samples exhibit greater energy absorption performance at the expense of durability. This trend is exaggerated during high-energy collisions. Comparison of the results to baseline tests with industry standard impact absorbing foam, wherein the spines exhibit similar energy absorption, verifies the dynamic impact absorption capabilities of hedgehog spines and their candidacy as a structural model for engineered impact technology.

  2. Impact Foam Testing for Multi-Mission Earth Entry Vehicle Applications

    NASA Technical Reports Server (NTRS)

    Glaab, Louis J.; Agrawal, Paul; Hawbaker, James

    2013-01-01

    Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, two different Rohacell foams were tested to determine their thermal conductivity in support of MMEEV design applications. These applications include thermal insulation during atmospheric entry, impact attenuation, and post-impact thermal insulation in support of thermal soak analysis. Results indicate that for these closed-cell foams, the effect of impact is limited on thermal conductivity due to the venting of the virgin material gas and subsequent ambient air replacement. Results also indicate that the effect of foam temperature is significant compared to data suggested by manufacturer's specifications.

  3. Integrated assessment of pedestrian head impact protection in testing secondary safety and autonomous emergency braking.

    PubMed

    Searson, D J; Anderson, R W G; Hutchinson, T P

    2014-02-01

    Pedestrian impact testing is used to provide information to the public about the relative level of protection provided by different vehicles to a struck pedestrian. Autonomous Emergency Braking (AEB) is a relatively new technology that aims to reduce the impact speed of such crashes. It is expected that vehicles with AEB will pose less harm to pedestrians, and that the benefit will come about through reductions in the number of collisions and a change in the severity of impacts that will still occur. In this paper, an integration of the assessment of AEB performance and impact performance is proposed based on average injury risk. Average injury risk is calculated using the result of an impact test and a previously published distribution of real world crash speeds. A second published speed distribution is used that accounts for the effects of AEB, and reduced average risks are implied. This principle allows the effects of AEB systems and secondary safety performance to be integrated into a single measure of safety. The results are used to examine the effect of AEB on Euro NCAP and ANCAP assessments using previously published results on the likely effect of AEB. The results show that, given certain assumptions about AEB performance, the addition of AEB is approximately the equivalent of increasing Euro NCAP test performance by one band, which corresponds to an increase in the score of 25% of the maximum.

  4. Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Billings, Marcus D.

    2001-01-01

    The nonlinear, transient dynamic finite element code, MSC.Dytran, was used to simulate an impact test of an energy absorbing Earth Entry Vehicle (EEV) that will impact without a parachute. EEVOs are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the center of the EEVOs cellular structure. Pre-test analytical predictions were compared with the test results from a bungee accelerator. The model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAM1 model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for cellular impact.

  5. Impact Test and Simulation of Energy Absorbing Concepts for Earth Entry Vehicles

    NASA Technical Reports Server (NTRS)

    Billings, Marcus D.; Fasanella, Edwin L.; Kellas, Sotiris

    2001-01-01

    Nonlinear dynamic finite element simulations have been performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite- epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the center of the EEV's cellular structure. Comparisons of analytical predictions using MSC,Dytran with test results obtained from impact tests performed at NASA Langley Research Center were made for three impact velocities ranging from 32 to 40 m/s. Acceleration and deformation results compared well with the test results. These finite element models will be useful for parametric studies of off-nominal impact conditions.

  6. Irradiation effects on impact behavior of 12Cr-1MoVW and 2 1/4Cr-1Mo steels

    SciTech Connect

    Klueh, R.L.; Alexander, D.J.

    1990-01-01

    Charpy impact tests were conducted on 12CR-1MoVW steel after irradiation in the Fast Flux Test Facility (FFTF) and the Oak Ridge Research Reactor (OOR). One-half-size and one-third-size Charpy specimens were irradiated in FFTF at 365{degree}C. After irradiating half-size-specimens to {approximately}10 and 17 dpa, a shift in ductile-brittle-transition temperature (DBTT) of 160{degree}C was observed for both fluences, indicating a saturation in the shift. A shift DBTT of 151{degree}C was observed for the third-size specimens after irradiation to 10 dpa. Third-size specimens of 12Cr--1MoVW steel irradiated {approximately}7 dpa in the ORR at 330 and 400{degree}C developed shifts in DBTT of 200 and 120{degree}C, respectively, somewhat above and below the shifts observed after irradiation at 365{degree}C in FFTF. This correspondence of results in the mixed-spectrum ORR and the fast-spectrum FFTF is in marked contrast to large differences observed between specimens irradiated in the mixed-spectrum High Flux Isotope Reactor and the fast spectrum Experimental Breeder Reactor. The first data on the effect of fast reactor irradiation on the impact behavior 2{1/4} CR--1Mo steel were obtained. Third-size specimens were irradiated in FFTF to {approximately}10 dpa at 365{degree}C. An increase in DBTT of 170{degree}C was observed, similar of the shift observed for 12Cr--1MoVW steel following comparable irradiation. The reduction in the upper-shelf energy for the 2{1/4} Cr--1Mo steel was less than that observed for 12Cr--1MoVW steel. Because of the low DBTT of unirradiated 2{1/4} Cr--1Mo steel, the DBTT after irradiation remained below that for 12Cr--1MoVW steel.

  7. High-speed impact test using an inertial mass and an optical interferometer

    NASA Astrophysics Data System (ADS)

    Jin, T.; Watanabe, K.; Prayogi, I. A.; Takita, A.; Mitatha, S.; Djamal, M.; Jia, H. Z.; Hou, W. M.; Fujii, Y.

    2013-07-01

    A high-speed impact testing method for evaluating mechanical properties of materials is proposed using an inertial mass and a dual beat-frequencies laser Doppler interferometer (DB-LDI). In this method, an inertial mass levitated using an aerostatic linear bearing is made to collide with the material being tested at a high initial velocity. During the collision, the velocity of the mass, which is even higher than the critical velocity (±0.56 m/s) defined by the frequency difference of the Zeeman laser, is accurately measured using the DB-LDI. The position, acceleration, and impact force of the mass are calculated from the measured velocity. Using the proposed method, the mechanical properties of a visco-elastic material under a high-speed impact loading condition can be accurately evaluated.

  8. Damage development in rod-on-rod impact test on 1100 pure aluminum

    NASA Astrophysics Data System (ADS)

    Iannitti, G.; Bonora, N.; Bourne, N.; Ruggiero, A.; Testa, G.

    2017-01-01

    Stress triaxiality plays a major role in the nucleation and growth of ductile damage in metals and alloys. Although, the mechanisms responsible for ductile failure are the same at low and high strain rate, in impact dynamics, in addition to time resolved stress triaxiality and plastic strain accumulation, pressure also contributes to establish the condition for ductile failure to occur. In this work, ductile damage development in 1100 commercially pure aluminum was investigated by means of rod-on-rod (ROR) impact tests. Based on numerical simulations, using a continuum damage mechanics (CDM) model that accounts for the role of pressure on damage parameters and stochastic variability of such parameters, the impact velocity for no damage, incipient and fully developed damage were estimated. ROR tests at selected velocities were performed and damage distribution and extent were investigated by sectioning of soft recovered samples. Comparison between numerical simulations and experimental results is presented and discussed.

  9. A Comparison of Quasi-Static Indentation and Drop-Weight Impact Testing on Carbon/Epoxy Laminates

    NASA Technical Reports Server (NTRS)

    Prabhakaran, R.; Douglas, Michael J.

    2000-01-01

    This project was initiated to investigate the damage tolerance of polymer matrix composites (PMC). After a low velocity impact-such as the ones that can occur during manufacturing or service there is usually very little visual damage. There are two possible methods to simulate foreign object impact on PMC: static indentation and drop weight impact. A static method for modeling low velocity foreign object impact events for composites can prove to be very beneficial to researchers since much more data can be obtained from a static test than from an impact test. In order to examine if this is feasible, a series of static indentation and low velocity impact tests were performed and compared. Square specimens of different sizes and thicknesses were tested to cover a wide array of low velocity impact events. Laminates with a 45 degree stacking sequence were used since this is a common type of engineering laminate. Three distinct flexural rigidities under two different boundary conditions were tested in order to obtain damage due to large deflections. Comparisons between static indentation and low velocity impact tests were based on the maximum applied transverse load. The dependent parameters examined were dent depth, back surface crack length, delamination area, and load-deflection behavior. Results showed that no distinct differences could be seen between the static indentation tests and the low velocity impact tests, indicating that static indentation tests can be used to simulate low velocity impact events.

  10. UTILIZATION OF ImPACT TESTING TO MEASURE INJURY RISK IN ALPINE SKI AND SNOWBOARD ATHLETES

    PubMed Central

    Huntimer, Brittney; Kernozek, Thomas; Cole, John

    2016-01-01

    ABSTRACT Background While studies that have examined the prevalence of musculoskeletal injuries in alpine skiing and snowboarding exist, there has been no discussion of how neurocognitive deficits may influence such injuries. Recent authors have identified a possible link between Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) testing results and the prevalence of musculoskeletal injury in athletic populations. However, no study has specifically examined this in the alpine skiing and snowboard athletes who sustain injury and those that do not. Hypothesis/Purpose The purpose was to review injury data and ImPACT test results within the local ski/snowboard population to determine if there was a difference in components of ImPACT test scores between injured and non-injured athletes. It was hypothesized that differences would exist in component scores on ImPACT testing between injured and non-injured athletes. Study design Retrospective cohort study Methods Injury records and baseline ImPACT testing scores for 93 athletes aged 14-17 participating in a local ski and snowboard club during the 2009-2012 seasons were gathered retrospectively. Injuries documented for the lower and upper extremity included ligament sprains, muscle strains, contusions, dislocation/subluxation, fractures and concussions. Athletes who sustained any of these listed injuries were categorized within the injured athlete group. Each component of ImPACT test scores was compared between gender and for injury status within skiing and snowboarding disciplines using a series of two-way analysis of variance tests. Results There was no difference between non-injured and injured females as well as non-injured and injured males in reaction time and visual motor speed (VMS), however there was an interaction between gender and injury status on composite reaction time and visual motor speed, or VMS. The composite reaction time for females was 4.7% faster with injury while males without injury

  11. The Impact of the 2004 Hurricanes on Florida Comprehensive Assessment Test Scores: Implications for School Counselors

    ERIC Educational Resources Information Center

    Baggerly, Jennifer; Ferretti, Larissa K.

    2008-01-01

    What is the impact of natural disasters on students' statewide assessment scores? To answer this question, Florida Comprehensive Assessment Test (FCAT) scores of 55,881 students in grades 4 through 10 were analyzed to determine if there were significant decreases after the 2004 hurricanes. Results reveal that there was statistical but no practical…

  12. School Counselors' Perceptions of the Impact of High-Stakes Testing

    ERIC Educational Resources Information Center

    Brown, Duane; Galassi, John P.; Akos, Patrick

    2004-01-01

    Two studies of school counselors' perceptions of the impact of the North Carolina ABC (high-stakes) testing program are reported in this article. (For ease of interpretation, percentages were rounded to the nearest whole number in both studies.) One hundred forty-one counselors who attended their state association's professional conference…

  13. Testing the Generalizability of a Career Commitment Measure and Its Impact on Employee Turnover.

    ERIC Educational Resources Information Center

    Blau, Gary

    1989-01-01

    Tested generalizability of career commitment measure and its impact on employee turnover using longitudinally tracked sample of bank tellers (N=133). Found career commitment could be reliably operationalized and was distinct from job involvement and organizational commitment. Discusses findings in terms of identifying threshold level for…

  14. The Overall Impact of Testing on Medical Student Learning: Quantitative Estimation of Consequential Validity

    ERIC Educational Resources Information Center

    Kreiter, Clarence D.; Green, Joseph; Lenoch, Susan; Saiki, Takuya

    2013-01-01

    Given medical education's longstanding emphasis on assessment, it seems prudent to evaluate whether our current research and development focus on testing makes sense. Since any intervention within medical education must ultimately be evaluated based upon its impact on student learning, this report seeks to provide a quantitative accounting of…

  15. Measuring the Impact of Language-Learning Software on Test Performance of Chinese Learners of English

    ERIC Educational Resources Information Center

    Nicholes, Justin

    2016-01-01

    This classroom quasi-experiment aimed to learn if and to what degree supplementing classroom instruction with Rosetta Stone (RS), Tell Me More (TMM), Memrise (MEM), or ESL WOW (WOW) impacted high-stakes English test performance in areas of university-level writing, reading, speaking, listening, and grammar. Seventy-eight (N = 78) Chinese learners…

  16. Thoracic response to high-rate blunt impacts using an advanced testing platform.

    PubMed

    Wickwire, Alexis C; Merkle, Andrew C; Carneal, Catherine M; Pauson, Jeffrey M

    2012-01-01

    ehind Armor Blunt Trauma (BABT) is a persistent concern for both the military and civil law enforcement. Although personal protective equipment (PPE), including soft and hard body armor, mitigates penetrating injuries from ballistic threats, the impact generates a backface deformation which creates a high-rate blunt impact to the body and potential internal injury (i.e., BABT). A critical need exists to understand the mechanics of the human response and subsequently evaluate the efficacy of current and proposed PPE in mitigating BABT injury risk. Current human surrogate test platforms lack anatomical fidelity or instrumentation for capturing the dynamic transfer of energy during the event. Therefore, we have developed and tested a Human Surrogate Torso Model (HSTM) composed of biosimulants representing soft tissues and skeleton of the human torso. A matrix of pressure transducers were embedded in the soft tissue and a custom displacement sensor was mounted to the skeletal structure to measure sternum displacement. A series of non-penetrating, high energy ballistic tests were performed with the HSTM. Results indicate that both sternum displacement and internal localized pressure are sensitive to impact energy and location. These data provide a spatial and temporal comparison to the current standard (static clay measurements) and a method for evaluating the applicability of thoracic injury metrics, including the Viscous Criterion, for BABT. The HSTM provides an advanced, biomechanically relevant test platform for determining the thoracic response to dynamic loading events due to non-penetrating ballistic impacts.

  17. The Impact of Discourse Features of Science Test Items on ELL Performance

    ERIC Educational Resources Information Center

    Kachchaf, Rachel; Noble, Tracy; Rosebery, Ann; Wang, Yang; Warren, Beth; O'Connor, Mary Catherine

    2014-01-01

    Most research on linguistic features of test items negatively impacting English language learners' (ELLs') performance has focused on lexical and syntactic features, rather than discourse features that operate at the level of the whole item. This mixed-methods study identified two discourse features in 162 multiple-choice items on a standardized…

  18. The Impact of Success Maker Software on Grade 4 Math Proficiency on State Tests

    ERIC Educational Resources Information Center

    Geer, Brandon Terrell

    2014-01-01

    Success Maker is an educational software that differentiates and personalizes K-8 reading and math. Limited research has been conducted on the impact of Success Maker on Grade 4 math state tests. At the research site, located in southeastern United States, 33.7% of fourth grade students did not pass the Palmetto Assessment of State Standards…

  19. A unique facility for V/STOL aircraft hover testing. [Langley Impact Dynamics Research Facility

    NASA Technical Reports Server (NTRS)

    Culpepper, R. G.; Murphy, R. D.; Gillespie, E. A.; Lane, A. G.

    1979-01-01

    The Langley Impact Dynamics Research Facility (IDRF) was modified to obtain static force and moment data and to allow assessment of aircraft handling qualities during dynamic tethered hover flight. Test probe procedures were also established. Static lift and control measurements obtained are presented along with results of limited dynamic tethered hover flight.

  20. Using Tests To Evaluate the Impact of Curricular Reform on Higher Order Thinking.

    ERIC Educational Resources Information Center

    Davis, Alan

    The dominant issues in considering the use of tests developed outside the classroom to measure the impact of curriculum reform on higher order thinking are reviewed by a panel interviewed for this discussion. Panel members are: (1) Stuart Kahl, (2) Robert Linn, (3) Senta A. Raizen, (4) Lauren Resnick, and (5) Thomas A. Romberg. It is conceded…

  1. Head impact mechanisms of a child occupant seated in a child restraint system as determined by impact testing.

    PubMed

    Yoshida, Ryoichi; Okada, Hiroshi; Nomura, Mitsunori; Mizuno, Koji; Tanaka, Yoshinori; Hosokawa, Naruyuki

    2011-11-01

    In side collision accidents, the head is the most frequently injured body region for child occupants seated in a child restraint system (CRS). Accident analyses show that a child's head can move out of the CRS shell, make hard contact with the vehicle interior, and thus sustain serious injuries. In order to improve child head protection in side collisions, it is necessary to understand the injury mechanism of a child in the CRS whose head makes contact with the vehicle interior. In this research, an SUV-to-car oblique side crash test was conducted to reconstruct such head contacts. A Q3s child dummy was seated in a CRS in the rear seat of the target car. The Q3s child dummy's head moved out beyond the CRS side wing, moved laterally, and made contact with the side window glass and the doorsill. It was demonstrated that the hard head contact, which produced a high HIC value, could occur in side collisions. A series of sled tests was carried out to reproduce the dummy kinematic behavior observed in the SUV-to-car crash test, and the sled test conditions such as sled angle, ECE seat slant angle and velocity-time history that duplicated the kinematic behavior were determined. A parametric study also was conducted with the sled tests; and it was found that the impact angle, harness slack, chest clip, and the CRS side wing shape affected the torso motion and head contact with the vehicle interior.

  2. Low amplitude impact testing and analysis of pristine and aged solid high explosives

    SciTech Connect

    Chidester, S K; Garza, R; Tarver, C M

    1998-08-17

    The critical impact velocities of 60.1 mm diameter blunt steel projectiles required for ignition of exothermic chemical reaction were determined for heavily confined charges of new and aged (15-30 years) solid HMX-based high explosives. The explosives in order of decreasing impact sensitivity were: PBX 9404; LX-lo; LX-14; PBX 9501; and LX-04. Embedded pressure gauges measured the interior pressure histories. Stockpile aged LX-04 and PBX 9501 from dismantled units were tested and compared to freshly pressed charges. The understanding of explosive aging on impact ignition and other hazards must improve as systems are being deployed longer than their initial estimated lifetimes. The charges that did not react on the first impact were subjected to multiple impacts. While the violence of reaction increased with impact velocity, it remained much lower than that produced by an intentional detonation. Ignition and Growth reactive flow models were developed to predict HMX-based explosive impact sensitivity in other geometries and scenarios.

  3. Measurement of Head Impact Due to Standing Fall in Adults Using Anthropomorphic Test Dummies.

    PubMed

    Hajiaghamemar, Marzieh; Seidi, Morteza; Ferguson, James R; Caccese, Vincent

    2015-09-01

    The kinematics and kinetics of head impact due to a standing fall onto a hard surface are summarized. Head injury due to impact from falls represents a significant problem, especially for older individuals. When the head is left unprotected during a fall, the impact severity can be high enough to cause significant injury or even death. To ascertain the range of head impact parameters, the dynamic response was captured for the pedestrian version of the 5th percentile female and 50th percentile male Hybrid III anthropomorphic test dummies as they were dropped from a standing position with different initial postures. Five scenarios of falls were considered including backward falls with/without hip flexion, forward falls with/without knee flexion and lateral falls. The results show that the head impact parameters are dependent on the fall scenario. A wide range of impact parameters was observed in 107 trials. The 95% prediction interval for the peak translational acceleration, peak angular acceleration, peak force, impact translational velocity and peak angular velocity are 146-502 g, 8.8-43.3 krad/s(2), 3.9-24.5 kN, 2.02-7.41 m/s, and 12.9-70.3 rad/s, respectively.

  4. Asteroid Impact and Deflection Assessment mission: the Double Asteroid Redirection Test (DART)

    NASA Astrophysics Data System (ADS)

    Cheng, A.; Michel, P.

    2015-10-01

    The Asteroid Impact & Deflection Assessment (AIDA) mission will be the first space experiment to demonstrate asteroid impact hazard mitigation by using a kinetic impactor. AIDA is a joint ESA-NASA cooperative project, which includes the ESA Asteroid Impact Mission (AIM) rendezvous spacecraft and the NASA Double Asteroid Redirection Test (DART) mission. The AIDA target is the near-Earth binary asteroid 65803 Didymos, which will make an unusually close approach to Earth in October, 2022. The ~300-kg DART spacecraft is designed to impact the Didymos secondary at 6.5 km/s and demonstrate the ability to modify its trajectory through momentum transfer. The primary goals of AIDA are (i) to investigate the binary near-Earth asteroid (65803) Didymos, (ii) to demonstrate asteroid deflection by kinetic impact and to characterize the deflection. The primary DART objectives are to demonstrate a hypervelocity impact on the Didymos moon and to determine the resulting deflection from ground-based observatories. The DART impact on the Didymos secondary will cause a measurable change in the orbital period of the binary.

  5. A Unified Theory of Impact Crises and Mass Extinctions: Quantitative Tests

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.; Haggerty, Bruce M.; Pagano, Thomas C.

    1997-01-01

    Several quantitative tests of a general hypothesis linking impacts of large asteroids and comets with mass extinctions of life are possible based on astronomical data, impact dynamics, and geological information. The waiting of large-body impacts on the Earth derive from the flux of Earth-crossing asteroids and comets, and the estimated size of impacts capable of causing large-scale environmental disasters, predict that impacts of objects greater than or equal to 5 km in diameter (greater than or equal to 10 (exp 7) Mt TNT equivalent) could be sufficient to explain the record of approximately 25 extinction pulses in the last 540 Myr, with the 5 recorded major mass extinctions related to impacts of the largest objects of greater than or equal to 10 km in diameter (greater than or equal to 10(exp 8) Mt Events). Smaller impacts (approximately 10 (exp 6) Mt), with significant regional environmental effects, could be responsible for the lesser boundaries in the geologic record.

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

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    1991-01-01

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

  7. Assessing the social impact of direct-to-consumer genetic testing: understanding sociotechnical architectures.

    PubMed

    Parthasarathy, Shobita

    2010-09-01

    To properly understand the social impact of direct-to-consumer genetic testing, we must consider the "sociotechnical architectures" of these technologies--how developers design and assemble the human and technical components of individual testing systems to perform specific functions. In particular, the way testing systems perform their main functions--providing access to testing, analyzing genetic material, and conveying test results--influence the technology's utility and the distribution of expertise in the medical system. I illustrate this concept by comparing two systems that offer single-nucleotide polymorphism analysis, a relatively new type of genetic testing. I conclude by exploring how policy officials and other decision makers might intervene in the development of sociotechnical architectures to maximize the benefits of genomic technologies.

  8. Impact and hardness optimisation of composite materials inspired by the babassu nut (Orbignya speciosa).

    PubMed

    Staufenberg, Gerrit; Graupner, Nina; Müssig, Jörg

    2015-08-20

    The babassu nut is the fruit of the babassu palm Orbignya speciosa. The combination of hardness and impact strength is difficult to acquire for artificial materials, making the babassu nut a promising source for biomimetic inspiration. Unnotched Charpy impact tests, Shore D hardness tests and scanning electron microscopy were used for mechanical and microscopical analysis of the pericarp. Four major principles were found for a biomimetic approach: a hard core ((1); endocarp) is embedded in a soft outer layer of high impact strength ((2); epicarp) and is reinforced with fibres of variable fineness (3), some of which are oriented radial to the core (4). Biomimetic fibre-reinforced composites were produced using abstracted mechanisms of the babassu nut based on regenerated cellulose fibres (lyocell, L) with two different fineness values as reinforcement embedded in a polylactide (PLA) core matrix and polypropylene (PP) based outer layers. The biomimetic fibre composite reaches a significantly higher impact strength that is 1.6 times higher than the reference sample produced from a PLA/PP/L-blend. At the same time the hardness is slightly increased compared to PP/L.

  9. Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test

    SciTech Connect

    Forbes, J.W.; Tarver, C.M.; Chidester, S.K.; Garcia, F.; Greenwood, D.W.; Garza, R.

    2000-10-10

    The two-dimensional Steven impact test has been developed to be reproducible and amenable to computer modeling. This test has a hemispherical projectile traveling at tens of m/s impacting a metal cased explosive target. To assist in the understanding of this safety test, two-dimensional shock wave gauge techniques were used to measure the pressures of a few kilobars and times of reactions less than a millisecond. This work is in accord with a long-term goal to develop two-dimensional shock diagnostic techniques that are more than just time of arrival indicators. Experiments were performed where explosives were impacted at levels below shock initiation levels but caused low level reactions. Carbon foil and carbon resistor pressure gauges were used to measure pressures and time of events. The carbon resistor gauges indicate a late time low level reaction at 350 {micro}s after impact of the hemispherical projectile creating 0.5-6 kb peak shocks at the center of PBX 9501 (HMX/Estane/BDNPA-F; 95/2.5/2.5 wt %) explosive discs. The Steven test calculations are based on an ignition and growth criteria and found that the low level reaction occurs at 335 {micro}s, which is in good agreement with the experimental data. Some additional experiments simulating the Steven impact test were done on a gas gun with carbon foil and constantan strain gauges in a PMMA target. Hydrodynamic calculations can be used to evaluate the gauge performance in these experiments and check the lateral strain measurements.

  10. Impact Testing of Stainless Steel Material at Room and Elevated Temperatures

    SciTech Connect

    Dana K. Morton; Spencer D. Snow; Tom E. Rahl; Robert K. Blandford

    2007-07-01

    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 are not well documented. However, three previous papers [1, 2, 3] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens that began the investigation of these characteristics. The goal of the work presented herein is to add the results of additional tensile impact testing for 304/304L and 316/316L stainless steel material specimens. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, additional tests achieved target strain rates of 5, 10, and 22 per second at room temperature, 300, and 600 degrees Fahrenheit. Elevated true stress-strain curves for these materials at each designated strain rate and temperature are presented herein.

  11. Simulation of an Impact Test of the All-Composite Lear Fan Aircraft

    NASA Technical Reports Server (NTRS)

    Stockwell, Alan E.; Jones, Lisa E. (Technical Monitor)

    2002-01-01

    An MSC.Dytran model of an all-composite Lear Fan aircraft fuselage was developed to simulate an impact test conducted at the NASA Langley Research Center Impact Dynamics Research Facility (IDRF). The test was the second of two Lear Fan impact tests. The purpose of the second test was to evaluate the performance of retrofitted composite energy-absorbing floor beams. A computerized photogrammetric survey was performed to provide airframe geometric coordinates, and over 5000 points were processed and imported into MSC.Patran via an IGES file. MSC.Patran was then used to develop the curves and surfaces and to mesh the finite element model. A model of the energy-absorbing floor beams was developed separately and then integrated into the Lear Fan model. Structural responses of components such as the wings were compared with experimental data or previously published analytical data wherever possible. Comparisons with experimental results were used to guide structural model modifications to improve the simulation performance. This process was based largely on qualitative (video and still camera images and post-test inspections) rather than quantitative results due to the relatively few accelerometers attached to the structure.

  12. Elemental Water Impact Test: Phase 3 Plunge Depth of a 36-Inch Aluminum Tank Head

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2014-01-01

    Spacecraft are being designed based on LS-DYNA water landing simulations. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 3 featured a composite tank head that was tested at a range of heights to verify the ability to predict structural failure of composites. To support planning for Phase 3, a test series was conducted with an aluminum tank head dropped from heights of 2, 6, 10, and 12 feet to verify that the test article would not impact the bottom of the test pool. This report focuses on the comparisons of the measured plunge depths to LS-DYNA predictions. The results for the tank head model demonstrated the following. 1. LS-DYNA provides accurate predictions for peak accelerations. 2. LS-DYNA consistently under-predicts plunge depth. An allowance of at least 20% should be added to the LS-DYNA predictions. 3. The LS-DYNA predictions for plunge depth are relatively insensitive to the fluid-structure coupling stiffness.

  13. LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN

    SciTech Connect

    Chidester, S K; Vandersall, K S; Switzer, L L; Tarver, C M

    2005-07-18

    Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 170-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04 has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence.

  14. Test and Analysis of Foam Impacting a 6x6 Inch RCC Flat Panel

    NASA Technical Reports Server (NTRS)

    Lessard, Wendy B.

    2006-01-01

    This report presents the testing and analyses of a foam projectile impacting onto thirteen 6x6 inch flat panels at a 90 degrees incidence angle. The panels tested in this investigation were fabricated of Reinforced-Carbon-Carbon material and were used to aid in the validation of an existing material model, MAT58. The computational analyses were performed using LS-DYNA, which is a physics-based, nonlinear, transient, finite element code used for analyzing material responses subjected to high impact forces and other dynamic conditions. The test results were used to validate LS-DYNA predictions and to determine the threshold of damage generated by the MAT58 cumulative damage material model. The threshold of damage parameter represents any external or internal visible RCC damage detectable by nondestructive evaluation techniques.

  15. LX-04 Violence Measurements-Steven Tests Impacted by Projectiles Shot from a Howitzer Gun

    NASA Astrophysics Data System (ADS)

    Chidester, Steven K.; Vandersall, Kevin S.; Switzer, Lori L.; Tarver, Craig M.

    2006-07-01

    Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 170-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04 has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence.

  16. Screening Tests for Enhanced Shielding Against Hypervelocity Particle Impacts for Future Unmanned Spacecraft

    NASA Astrophysics Data System (ADS)

    Putzar, Robin; Hupfer, Jan; Aridon, Gwenaelle; Gergonne, Bernard; David, Matthieu; Bourke, Paul; Cougnet, Claude

    2013-08-01

    Protection of components of unmanned spacecraft against particle impacts is typically provided by the spacecraft's structure together with the intrinsic protection capabilities of the components themselves. Thus to increase the survivability of future spacecraft, one option is to enhance the protection already provided using enhanced materials and additional shielding. As part of the EU funded FP7 research project ReVuS ("Reducing the Vulnerability of Space systems"), the configurations of equipment typically found on board unmanned spacecraft were identified. For each of those configurations, potential solutions have been identified which enhance the robustness against particle impacts. The solutions are broken down into a number of shielding components that include e.g. additional protective layers made from aluminum, Kevlar, Nextel, stainless steel mesh and ceramics. To evaluate the characteristics and performances of these shielding components, a number of screening hypervelocity impact tests were performed. During these tests, representative configurations have been subjected to impacts of aluminum spheres of 3 mm and 5 mm diameter at a nominal impact velocity of 7 km/s. This paper describes the targets and presents and compares the results.

  17. Dust Impact Monitor (DIM) onboard Rosetta/Philae: Tests with ice particles as comet analog materials

    NASA Astrophysics Data System (ADS)

    Flandes, Alberto; Krüger, Harald; Loose, Alexander; Albin, Thomas; Arnold, Walter

    2014-09-01

    In 2014 the European Space Agency's spacecraft Rosetta will encounter the short-period comet 67P/Churyumov-Gerasimenko. Rosetta carries the lander spacecraft Philae on board which will attempt to land on the comet's nucleus. Amongst Philae's instruments, the Dust Impact Monitor (DIM) using piezoelectric sensors is aimed at measuring the physical properties (size and impact speed) of the millimetric and submillimetric dust and ice particles that move near the surface of comet 67P. Given that DIM has three orthogonal sensor sides (with about 70 cm2) total area), it will also be able to collect dynamical data, like an estimation of the particle flux in three dimension, that will help to derive daily and secular variations in the surface activity. We show the results of a series of calibration experiments with the goal to extend the performance tests of DIM. We tested DIM under particle impacts of densities similar to and larger than that of water ice (0.92-7.80 g/cm3) and at speeds from 0.3 to 1.9 m/s. Then, we performed experiments with spherical water ice particles between -40 °C and -20 °C. Finally, we measured the coefficient of restitution (COR) of the impacting particles. These data show that there is a loss mechanism in the impact which is caused by plastic deformation in the contact zones of both the impinging particle and the PZT sensor.

  18. The impact of neurodynamic testing on the perception of experimentally induced muscle pain.

    PubMed

    Coppieters, Michel W; Kurz, Kimberly; Mortensen, Thor Einar; Richards, Nicola L; Skaret, Ingrid A; McLaughlin, Laurie M; Hodges, Paul W

    2005-02-01

    Neurodynamic tests such as the straight leg raising (SLR) and slump test are frequently used for assessment of mechanosensitivity of neural tissues. However, there is ongoing debate in the literature regarding the contributions of neural and non-neural tissues to the elicited symptoms because many structures are affected by these tests. Sensitizing manoeuvres are limb or spinal movements added to neurodynamic tests, which aim to identify the origin of the symptoms by preferentially loading or unloading neural structures. A prerequisite for the use of sensitizing manoeuvres to identify neural involvement is that the addition of sensitizing manoeuvres has no impact on pain perception when the origin of the pain is non-neural. In this study, experimental muscle pain was induced by injection of hypertonic saline in tibialis anterior or soleus in 25 asymptomatic, naive volunteers. A first experiment investigated the impact of hip adduction, abduction, medial and lateral rotation in the SLR position. In a second experiment, the different stages of the slump test were examined. The intensity and area of experimentally induced muscle pain did not increase when sensitizing manoeuvres were added to the SLR or throughout the successive stages of the slump test. The findings of this study lend support to the validity of the use of sensitizing manoeuvres during neurodynamic testing.

  19. Effect of the Simulated Disinfection by Microwave Energy on the Impact Strength of the Tooth/Acrylic Resin Adhesion

    PubMed Central

    Consani, Rafael L.X.; Mesquita, Marcelo F.; Zampieri, Marinaldo H.; Mendes, Wilson B.; Consani, Simonides

    2008-01-01

    The objective of this study was to determine the effect of simulated microwave disinfection on the tooth/acrylic resin impact strength. Acrylic molar teeth with a wax stick attached to the ridge lap were included in brass flasks. Specimens were made with Classico thermopolymerized acrylic resin, according to the groups: 1 and 5 - tooth with no treatment (control); 2 and 6 – tooth bur abrasion; 3 and 7 – tooth bur retention; and 4 and 8 – tooth monomer etch. Eighty specimens (n=10) were polymerized in bath cycle at 74ºC for 9 hours and deflasked after flask cooling. Specimen from groups 2, 4, 6 and 8 was submitted to simulated microwave disinfection in a microwave oven at 650W for 3 minutes. Impact strength test was performed with an Otto Wolpert-Werke machine (Charpy system) with an impact load of 40 kpcm. Fracture load value was transformed into impact strength as a function of the bond area (kfg/cm2). Collected data were submitted to ANOVA and Tukey’s test (α=.05) and results indicate that the simulated microwave disinfection decreased the impact strength in all treatments. PMID:19088877

  20. ACTUAL WASTE TESTING OF GYCOLATE IMPACTS ON THE SRS TANK FARM

    SciTech Connect

    Martino, C.

    2014-05-28

    Glycolic acid is being studied as a replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste Tank Farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the Tank Farm were addressed via a literature review and simulant testing, but several outstanding issues remained. This report documents the actual-waste tests to determine the impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The objectives of this study are to address the following: Determine the extent to which sludge constituents (Pu, U, Fe, etc.) dissolve (the solubility of sludge constituents) in the glycolate-containing 2H-evaporator feed. Determine the impact of glycolate on the sorption of fissile (Pu, U, etc.) components onto sodium aluminosilicate solids. The first objective was accomplished through actual-waste testing using Tank 43H and 38H supernatant and Tank 51H sludge at Tank Farm storage conditions. The second objective was accomplished by contacting actual 2H-evaporator scale with the products from the testing for the first objective. There is no anticipated impact of up to 10 g/L of glycolate in DWPF recycle to the Tank Farm on tank waste component solubilities as investigated in this test. Most components were not influenced by glycolate during solubility tests, including major components such as aluminum, sodium, and most salt anions. There was potentially a slight increase in soluble iron with added glycolate, but the soluble iron concentration remained so low (on the order of 10 mg/L) as to not impact the iron to fissile ratio in sludge. Uranium and plutonium appear to have been supersaturated in 2H-evaporator feed solution mixture used for this testing. As a result, there was a reduction of soluble uranium and plutonium as a function of time. The change in soluble uranium concentration was

  1. Assessing transportation infrastructure impacts on rangelands: test of a standard rangeland assessment protocol

    USGS Publications Warehouse

    Duniway, Michael C.; Herrick, Jeffrey E.; Pyke, David A.; Toledo, David

    2010-01-01

    Linear disturbances associated with on- and off-road vehicle use on rangelands has increased dramatically throughout the world in recent decades. This increase is due to a variety of factors including increased availability of all-terrain vehicles, infrastructure development (oil, gas, renewable energy, and ex-urban), and recreational activities. In addition to the direct impacts of road development, the presence and use of roads may alter resilience of adjoining areas through indirect effects such as altered site hydrologic and eolian processes, invasive seed dispersal, and sediment transport. There are few standardized methods for assessing impacts of transportation-related land-use activities on soils and vegetation in arid and semi-arid rangelands. Interpreting Indicators of Rangeland Health (IIRH) is an internationally accepted qualitative assessment that is applied widely to rangelands. We tested the sensitivity of IIRH to impacts of roads, trails, and pipelines on adjacent lands by surveying plots at three distances from these linear disturbances. We performed tests at 16 randomly selected sites in each of three ecosystems (Northern High Plains, Colorado Plateau, and Chihuahuan Desert) for a total of 208 evaluation plots. We also evaluated the repeatability of IIRH when applied to road-related disturbance gradients. Finally, we tested extent of correlations between IIRH plot attribute departure classes and trends in a suite of quantitative indicators. Results indicated that the IIRH technique is sensitive to direct and indirect impacts of transportation activities with greater departure from reference condition near disturbances than far from disturbances. Trends in degradation of ecological processes detected with qualitative assessments were highly correlated with quantitative data. Qualitative and quantitative assessments employed in this study can be used to assess impacts of transportation features at the plot scale. Through integration with remote

  2. Rapid impact testing for quantitative assessment of large populations of bridges

    NASA Astrophysics Data System (ADS)

    Zhou, Yun; Prader, John; DeVitis, John; Deal, Adrienne; Zhang, Jian; Moon, Franklin; Aktan, A. Emin

    2011-04-01

    Although the widely acknowledged shortcomings of visual inspection have fueled significant advances in the areas of non-destructive evaluation and structural health monitoring (SHM) over the last several decades, the actual practice of bridge assessment has remained largely unchanged. The authors believe the lack of adoption, especially of SHM technologies, is related to the 'single structure' scenarios that drive most research. To overcome this, the authors have developed a concept for a rapid single-input, multiple-output (SIMO) impact testing device that will be capable of capturing modal parameters and estimating flexibility/deflection basins of common highway bridges during routine inspections. The device is composed of a trailer-mounted impact source (capable of delivering a 50 kip impact) and retractable sensor arms, and will be controlled by an automated data acquisition, processing and modal parameter estimation software. The research presented in this paper covers (a) the theoretical basis for SISO, SIMO and MIMO impact testing to estimate flexibility, (b) proof of concept numerical studies using a finite element model, and (c) a pilot implementation on an operating highway bridge. Results indicate that the proposed approach can estimate modal flexibility within a few percent of static flexibility; however, the estimated modal flexibility matrix is only reliable for the substructures associated with the various SIMO tests. To overcome this shortcoming, a modal 'stitching' approach for substructure integration to estimate the full Eigen vector matrix is developed, and preliminary results of these methods are also presented.

  3. Low amplitude impact of PBX 9501: Modified Steven spigot gun tests

    SciTech Connect

    Idar, D.J.; Lucht, R.A.; Straight, J.W.

    1998-12-01

    Low-velocity mechanical impact and subsequent high explosive (HE) reaction are of concern in credible accident scenarios involving the handling, transport, and storage of nuclear weapons. Using modified Steven spigot gun tests, the authors have investigated the high-explosive violent-reaction (HEVR) potential of PBX 9501 to low-amplitude insult. Reliable modeling predictions require that one identify the relevant parameters and behavioral responses that are key to the reaction mechanism(s) in PBX 9501. Additional efforts have been targeted at identifying relevant differences in the response between baseline and stockpile-aged PBX 9501 to low-velocity impacts.

  4. Testing Method for Measuring Impact Strength of Bga Solder Joints on Electronic Package

    NASA Astrophysics Data System (ADS)

    Adachi, Tadaharu; Goto, Hirotaka; Araki, Wakako; Omori, Takahiro; Kawamura, Noriyasu; Mukai, Minoru; Kawakami, Takashi

    A pendulum-impact testing machine was developed to measure the impact strength of ball-grid-array (BGA) solder joints between an electronic package and a circuit board. Ball solders were connected to daisy-chain between a dummy electronic package and a circuit board. The upper side of the package was directly bonded to a load cell. The rear side of the circuit board was also bonded to an aluminum alloy block fixed on a base. A pendulum made of aluminum alloy was collided into the load cell to apply tensile impact to the solder joints through the load cell. The history of the impact load could be controlled by raising the angle of the pendulum. The fracture of a BGA solder joint was detected by measuring the resistance of the daisy-chain circuit on the board. Therefore, the impact strengths of the solder joints at electrical disconnection and mechanical breaking of all joints could be determined. The experimental results showed that this method is useful for measuring the impact strength of BGA solder joints.

  5. Spin Testing for Durability Began on a Self-Tuning Impact Damper for Turbomachinery Blades

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten; Mehmed, Oral

    2003-01-01

    NASA and Pratt & Whitney will collaborate under a Space Act Agreement to perform spin testing of the impact damper to verify damping effectiveness and durability. Pratt & Whitney will provide the turbine blade and damper hardware for the tests. NASA will provide the facility and perform the tests. Effectiveness and durability will be investigated during and after sustained sweeps of rotor speed through resonance. Tests of a platform wedge damper are also planned to compare its effectiveness with that of the impact damper. Results from baseline tests without dampers will be used to measure damping effectiveness. The self-tuning impact damper combines two damping methods-the tuned mass damper and the impact damper. It consists of a ball located within a cavity in the blade. This ball rolls back and forth on a spherical trough under centrifugal load (tuned mass damper) and can strike the walls of the cavity (impact damper). The ball s rolling natural frequency is proportional to the rotor speed and can be designed to follow an engine-order line (integer multiple of rotor speed). Aerodynamic forcing frequencies typically follow these engineorder lines, and a damper tuned to the engine order will most effectively reduce blade vibrations when the resonant frequency equals the engine-order forcing frequency. This damper has been tested in flat plates and turbine blades in the Dynamic Spin Facility. During testing, a pair of plates or blades rotates in vacuum. Excitation is provided by one of three methods--eddy-current engine-order excitation (ECE), electromechanical shakers, and magnetic bearing excitation. The eddy-current system consists of magnets located circumferentially around the rotor. As a blade passes a magnet, a force is imparted on the blade. The number of magnets used can be varied to change the desired engine order of the excitation. The magnets are remotely raised or lowered to change the magnitude of the force on the blades. The other two methods apply

  6. Impact Testing on Reinforced Carbon-Carbon Flat Panels with Ice Projectiles for the Space Shuttle Return to Flight Program

    NASA Technical Reports Server (NTRS)

    Melis, Matthew E.; Revilock, Duane M.; Pereira, Michael J.; Lyle, Karen H.

    2009-01-01

    Following the tragedy of the Orbiter Columbia (STS-107) on February 1, 2003, a major effort commenced to develop a better understanding of debris impacts and their effect on the space shuttle subsystems. An initiative to develop and validate physics-based computer models to predict damage from such impacts was a fundamental component of this effort. To develop the models it was necessary to physically characterize reinforced carbon-carbon (RCC) along with ice and foam debris materials, which could shed on ascent and impact the orbiter RCC leading edges. The validated models enabled the launch system community to use the impact analysis software LS-DYNA (Livermore Software Technology Corp.) to predict damage by potential and actual impact events on the orbiter leading edge and nose cap thermal protection systems. Validation of the material models was done through a three-level approach: Level 1--fundamental tests to obtain independent static and dynamic constitutive model properties of materials of interest, Level 2--subcomponent impact tests to provide highly controlled impact test data for the correlation and validation of the models, and Level 3--full-scale orbiter leading-edge impact tests to establish the final level of confidence for the analysis methodology. This report discusses the Level 2 test program conducted in the NASA Glenn Research Center (GRC) Ballistic Impact Laboratory with ice projectile impact tests on flat RCC panels, and presents the data observed. The Level 2 testing consisted of 54 impact tests in the NASA GRC Ballistic Impact Laboratory on 6- by 6-in. and 6- by 12-in. flat plates of RCC and evaluated three types of debris projectiles: Single-crystal, polycrystal, and "soft" ice. These impact tests helped determine the level of damage generated in the RCC flat plates by each projectile and validated the use of the ice and RCC models for use in LS-DYNA.

  7. Hypervelocity impact testing of the Space Station utility distribution system carrier

    NASA Technical Reports Server (NTRS)

    Lazaroff, Scott

    1993-01-01

    A two-phase, joint JSC and McDonnell Douglas Aerospace-Huntington Beach hypervelocity impact (HVI) test program was initiated to develop an improved understanding of how meteoroid and orbital debris (M/OD) impacts affect the Space Station Freedom (SSF) avionic and fluid lines routed in the Utility Distribution System (UDS) carrier. This report documents the first phase of the test program which covers nonpowered avionic line segment and pressurized fluid line segment HVI testing. From these tests, a better estimation of avionic line failures is approximately 15 failures per year and could very well drop to around 1 or 2 avionic line failures per year (depending upon the results of the second phase testing of the powered avionic line at White Sands). For the fluid lines, the initial McDonnell Douglas analysis calculated 1 to 2 line failures over a 30 year period. The data obtained from these tests indicate the number of predicted fluid line failures increased slightly to as many as 3 in the first 10 years and up to 15 for the entire 30 year life of SSF.

  8. HIV tests and new diagnoses declined after california budget cuts, but reallocating funds helped reduce impact.

    PubMed

    Leibowitz, Arleen A; Byrnes, Karen; Wynn, Adriane; Farrell, Kevin

    2014-03-01

    Historically, California supplemented federal funding of HIV prevention and testing so that Californians with HIV could become aware of their infection and obtain lifesaving treatment. However, budget deficits in 2009 led the state to eliminate its supplemental funding for HIV prevention. We analyzed the impact of California's HIV resource allocation change between state fiscal years 2009 and 2011. We found that the number of HIV tests declined 19 percent, from 66,629 to 53,760, in local health jurisdictions with high HIV burden. In low-burden jurisdictions, the number of HIV tests declined 90 percent, from 20,302 to 2,116. New diagnoses fell from 2,434 in 2009 to 2,235 in 2011 (calendar years) in high-burden jurisdictions and from 346 to 327 in low-burden ones. California's budget crunch prompted state and local programs to redirect remaining HIV funds from risk reduction education to testing activities. Thus, the impact of the budget cuts on HIV tests and new HIV diagnoses was smaller than might have been expected given the size of the cuts. As California's fiscal outlook improves, we recommend that the state restore supplemental funding for HIV prevention and testing.

  9. Use of laser shock waves to test piezochromic coatings for impact detection

    NASA Astrophysics Data System (ADS)

    Gehring, Florian; Boustie, Michel; Touchard, Fabienne; Chocinski-Arnault, Laurence; Guinard, Stéphane; Senani, Sophie

    2017-01-01

    The design of piezochromic pigments is a promising way to adjust smart painting and therefore to develop a "visual" impact detection coating. This paper deals with the possibility to use laser shock waves to test piezochromic coatings for impact detection. For that purpose, an experimental setup was developed in order to obtain compressive load in the coating thanks to the impedance mismatch between selected materials. An analytical modeling was used to validate the proposed method. The experimental investigation coupled with finite-element modeling on four smart coatings showed that these coatings can reveal impact location by a significant change of color if a relevant pressure threshold is reached. The results presented in this work are promising and demonstrate the ability of the proposed laser shock method for characterizing the pressure thresholds of piezochromic smart paintings. It opens the door for studying future smart paintings with different critical pressure levels, depending on the targeted application.

  10. Impact of presymptomatic genetic testing on young adults: a systematic review.

    PubMed

    Godino, Lea; Turchetti, Daniela; Jackson, Leigh; Hennessy, Catherine; Skirton, Heather

    2016-04-01

    Presymptomatic and predictive genetic testing should involve a considered choice, which is particularly true when testing is undertaken in early adulthood. Young adults are at a key life stage as they may be developing a career, forming partnerships and potentially becoming parents: presymptomatic testing may affect many facets of their future lives. The aim of this integrative systematic review was to assess factors that influence young adults' or adolescents' choices to have a presymptomatic genetic test and the emotional impact of those choices. Peer-reviewed papers published between January 1993 and December 2014 were searched using eight databases. Of 3373 studies identified, 29 were reviewed in full text: 11 met the inclusion criteria. Thematic analysis was used to identify five major themes: period before testing, experience of genetic counselling, parental involvement in decision-making, impact of test result communication, and living with genetic risk. Many participants grew up with little or no information concerning their genetic risk. The experience of genetic counselling was either reported as an opportunity for discussing problems or associated with feelings of disempowerment. Emotional outcomes of disclosure did not directly correlate with test results: some mutation carriers were relieved to know their status, however, the knowledge they may have passed on the mutation to their children was a common concern. Parents appeared to have exerted pressure on their children during the decision-making process about testing and risk reduction surgery. Health professionals should take into account all these issues to effectively assist young adults in making decisions about presymptomatic genetic testing.

  11. Environmental impact assessment of tailings dispersal from a uranium mine using toxicity testing protocols

    SciTech Connect

    Rippon, G.D.; Riley, S.J.

    1996-12-01

    Toxicity testing is a means of establishing the environmental risk of uranium tailings release. It is valuable in designing tailings containment structures because it assists in setting acceptable levels of risk of the design. This paper presents details of toxicity tests of the tailings from Ranger Uranium Mine, Northern Territory, Australia. The results suggest that the non-radiological toxicity of the tailings is low. The environmental risk of a tailings release is more likely to be related to the physical impacts of the tailings, including infilling of billabongs and changes in the sedimentology of riparian ecosystems rather than their biogeochemical impact. Two major results were: (1) water from treatment with washed tailing fines was not toxic to Hydra viridissima, and (2) mixtures of washed tailings fines and natural floodplain sediment (overlying water or elutriates) were not toxic to Hydra viridissima or Moinodaphnia macleayi. 33 refs., 4 figs., 3 tabs.

  12. Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test

    SciTech Connect

    Vandersall, K S; Switzer, L L; Garcia, F

    2005-09-26

    Steven Impact Tests were performed at low velocity on the explosives TNT, Comp B, and C-4 in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, or C-4 explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives.

  13. Preliminary burn and impact tests of hybrid polymeric composites. [preventing graphite fiber release

    NASA Technical Reports Server (NTRS)

    Tompkins, S. S.; Brewer, W. D.

    1978-01-01

    Free graphite fibers released into the environment from resin matrix composite components, as a result of fire and/or explosion, pose a potential hazard to electrical equipment. An approach to prevent the fibers from becoming airborne is to use hybrid composite materials which retain the fibers at the burn site. Test results are presented for three hybrid composites that were exposed to a simulation of an aircraft fire and explosion. The hybrid systems consisted of 16 plies of graphite-epoxy with two plies of Kevlar-, S-glass-, or boron-epoxy on each face. Two different test environments were used. In one environment, specimens were heated by convection only, and then impacted by a falling mass. In the other environment, specimens were heated by convection and by radiation, but were not impacted. The convective heat flux was about 100-120 kW/m in both environments and the radiative flux was about 110 kW/sq m.

  14. Testing impact attenuation on California playground surfaces made of recycled tires.

    PubMed

    Vidair, Charles; Haas, Robert; Schlag, Robert

    2007-12-01

    This study was conducted to determine whether rubberized playground surfaces made of recycled tires comply with state-mandated standards for impact attenuation (measured with an accelerometer), and whether their properties change in response to temperature or time. The Head Impact Criterion (HIC) standard of 1000 was found to be a more sensitive indicator of compliance than the G(max) standard of 200(g). Of 32 playgrounds tested, 22 (69 percent) failed the HIC standard. As the heights of playground structures increased, so did the likelihood that the rubberized surface below would fail the HIC standard. Rubberized surfaces gave stable readings for the first three months following installation, and higher values in response to increasing surface temperature. An excessively high percentage of playground surfaces made of recycled tires failed the state-mandated standards designed to prevent serious head injury from falls. Future failures might be prevented by requiring installers to perform post-installation testing to verify compliance.

  15. Dynamic fracture toughness of irradiated A533 Grade B Class 1 pressure vessel steel

    SciTech Connect

    Murty, K.L.; Bamford, W.H.; Shogun, R.P.

    1984-03-01

    The effect of neutron radiation on the fracture characteristics of an A533 Grade B Class 1 pressure vessel steel was investigated using standard and instrumented precracked Charpy impact tests. Use of the instrumented impact test with precracked specimens has allowed fracture toughness values to be determined from the Charpy test. Neutron exposure resulted in minute decreases in the upper-shelf Charpy energy and fracture toughness, and an increase in the ductile brittle transition temperature (DBTT). The Charpy transition temperature shifted about 29 K while the fracture toughness shift was about 20 K. The temperature variation of the dynamic yield strength exhibited dips at DBTT for both unirradiated archive and irradiated materials.

  16. Experimental and Modeling Studies of Crush, Puncture, and Perforation Scenarios in the Steven Impact Test

    SciTech Connect

    Vandersall, K S; Chidester, S K; Forbes, J W; Garcia, F; Greenwood, D W; Switzer, L L; Tarver, C M

    2002-06-28

    The Steven test and associated modeling has greatly increased the fundamental knowledge of practical predictions of impact safety hazards for confined and unconfined explosive charges. Building on a database of initial work, experimental and modeling studies of crush, puncture, and perforation scenarios were investigated using the Steven impact test. The descriptions of crush, puncture, and perforation arose from safety scenarios represented by projectile designs that ''crush'' the energetic material or either ''puncture'' with a pinpoint nose or ''perforate'' the front cover with a transportation hook. As desired, these scenarios offer different aspects of the known mechanisms that control ignition: friction, shear and strain. Studies of aged and previously damaged HMX-based high explosives included the use of embedded carbon foil and carbon resistor gauges, high-speed cameras, and blast wave gauges to determine the pressure histories, time required for an explosive reaction, and the relative violence of those reactions, respectively. Various ignition processes were modeled as the initial reaction rate expression in the Ignition and Growth reaction rate equations. Good agreement with measured threshold velocities, pressure histories, and times to reaction was calculated for LX-04 impacted by several projectile geometries using a compression dependent ignition term and an elastic-plastic model with a reasonable yield strength for impact strain rates.

  17. Impact of Ion Propulsion on Performance, Design, Testing and Operation of a Geosynchronous Spacecraft

    DTIC Science & Technology

    1990-06-01

    11 Title (Include Security Classification) IMPACT OF ION PROPULSION ON PERFORMANCE, DESIGN, TESTING AND OPERATION OF A GEOSYNCHRONOUS SATELLITE 12...June 1990 I 11 16 Supplementary Notation The views expressed in this thesis are those of the author and do not reflect the official policy or position...Abstract 21 Abstract Security Classification N unclassified/unlimited 11 same as report IJ DTIC users Unclassified 22a Name of Responsible Individual

  18. Evaluation of Test Methods To Determine the Impact Resistance of Exterior Insulation and Finish Systems (EIFS).

    DTIC Science & Technology

    1992-07-01

    be used effectively in new construction or retrofit applications. These systems usually contain: 1. Molded expanded polystyrene insulation board (MEPS...commonly referred to as "bead board," or extruded expanded polystyrene insulation board (XEPS), commonly referred to as "blue board." 2. An...Walls ( Expanded Polystyrene Insulation Faced with a Thin Rendering), M.O.A.T. n 22, June 1988. 7 ASTM D3029-90. "Standard Test Methods for Impact

  19. Normalizing and scaling of data to derive human response corridors from impact tests.

    PubMed

    Yoganandan, Narayan; Arun, Mike W J; Pintar, Frank A

    2014-06-03

    It is well known that variability is inherent in any biological experiment. Human cadavers (Post-Mortem Human Subjects, PMHS) are routinely used to determine responses to impact loading for crashworthiness applications including civilian (motor vehicle) and military environments. It is important to transform measured variables from PMHS tests (accelerations, forces and deflections) to a standard or reference population, termed normalization. The transformation process should account for inter-specimen variations with some underlying assumptions used during normalization. Scaling is a process by which normalized responses are converted from one standard to another (example, mid-size adult male to large-male and small-size female adults, and to pediatric populations). These responses are used to derive corridors to assess the biofidelity of anthropomorphic test devices (crash dummies) used to predict injury in impact environments and design injury mitigating devices. This survey examines the pros and cons of different approaches for obtaining normalized and scaled responses and corridors used in biomechanical studies for over four decades. Specifically, the equal-stress equal-velocity and impulse-momentum methods along with their variations are discussed in this review. Methods ranging from subjective to quasi-static loading to different approaches are discussed for deriving temporal mean and plus minus one standard deviation human corridors of time-varying fundamental responses and cross variables (e.g., force-deflection). The survey offers some insights into the potential efficacy of these approaches with examples from recent impact tests and concludes with recommendations for future studies. The importance of considering various parameters during the experimental design of human impact tests is stressed.

  20. Impact of 50% Alcohol to Jet Blends on Aviation Turbine Fuel Coalescence - Navy Coalescence Test

    DTIC Science & Technology

    2014-10-17

    Impact of 50% Alcohol to Jet Blends on Aviation Turbine Fuel Coalescence - Navy Coalescence Test NF&LCFT REPORT 441/15-001 17 October 2014...Alcohol to Jet Blends on Aviation Turbine Fuel Coalescence- Navy Coalescence Test 1.0 BACKGROUND In October 2009, Secretary of the Navy Ray Mabus...section 5.11.4 of MIL-STD- 3004D3, for aviation turbine fuel to be acceptable for fueling aircraft it shall contain no more 10 ppm by volume (ppmv

  1. Fluid-structure interaction analysis of the drop impact test for helicopter fuel tank.

    PubMed

    Yang, Xianfeng; Zhang, Zhiqiang; Yang, Jialing; Sun, Yuxin

    2016-01-01

    The crashworthiness of helicopter fuel tank is vital to the survivability of the passengers and structures. In order to understand and improve the crashworthiness of the soft fuel tank of helicopter during the crash, this paper investigated the dynamic behavior of the nylon woven fabric composite fuel tank striking on the ground. A fluid-structure interaction finite element model of the fuel tank based on the arbitrary Lagrangian-Eulerian method was constructed to elucidate the dynamic failure behavior. The drop impact tests were conducted to validate the accuracy of the numerical simulation. Good agreement was achieved between the experimental and numerical results of the impact force with the ground. The influences of the impact velocity, the impact angle, the thickness of the fuel tank wall and the volume fraction of water on the dynamic responses of the dropped fuel tank were studied. The results indicated that the corner of the fuel tank is the most vulnerable location during the impact with ground.

  2. Impact testing to determine the mechanical properties of articular cartilage in isolation and on bone.

    PubMed

    Burgin, Leanne V; Aspden, Richard M

    2008-02-01

    The biomechanical response of cartilage to impact loads, both in isolation and in situ on its bone substrate, has been little studied despite the common occurrence of osteoarthritis subsequent to cartilage injury. An instrumented drop tower was used to apply controlled impact loads of different energies to explants of bovine articular cartilage. Results were compared with a conventional slow stress-strain test. The effects of the underlying bone were investigated by progressively shortening a core of bone removed with the cartilage, and by gluing cartilage samples to substrates of different moduli. The maximum dynamic modulus of isolated samples of bovine articular cartilage, at strain rates between 1100 and 1500 s(-1), was approximately two orders of magnitude larger than the quasistatic modulus and varied non-linearly with applied stress. When attached to a substrate of higher modulus, increasing the thickness of the substrate increased the effective modulus of the combination until a steady value was achieved. A lower modulus substrate reduced the effective modulus of the combination. Severe impacts resulted in damage to the bone rather than to the cartilage. The modulus of cartilage rises rapidly and non-linearly with strain rate, giving the tissue a remarkable ability to withstand impact loads. The presence of cartilage attenuated the peak force experienced by the bone and spread the impact loading period over a longer time.

  3. Accountability and Teacher Practice: Investigating the Impact of a New State Test and the Timing of State Test Adoption on Teacher Time Use

    ERIC Educational Resources Information Center

    Cocke, Erin F.; Buckley, Jack; Scott, Marc A.

    2011-01-01

    There is much debate over the impact of high stakes testing as well as a growing body of research focused on both the intended and unintended consequences of these tests. One claim of both the popular media and education researchers is that high stakes tests have led to curricular narrowing--the idea that school time is increasingly allocated to…

  4. Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives.

    PubMed

    Kozowyk, P R B; Langejans, G H J; Poulis, J A

    2016-01-01

    The production of compound adhesives using disparate ingredients is seen as some of the best evidence of advanced cognition outside of the use of symbolism. Previous field and laboratory testing of adhesives has shown the complexities involved in creating an effective Middle Stone Age glue using Acacia gum. However, it is currently unclear how efficient different adhesive recipes are, how much specific ingredients influence their performance, and how difficult it may have been for those ingredients to be combined to maximum effect. We conducted a series of laboratory-based lap shear and impact tests, following modern adhesion testing standards, to determine the efficacy of compound adhesives, with particular regard to the ingredient ratios. We tested rosin (colophony) and gum adhesives, containing additives of beeswax and ochre in varying ratios. During both lap shear and impact tests compound rosin adhesives performed better than single component rosin adhesives, and pure acacia gum was the strongest. The large difference in performance between each base adhesive and the significant changes in performance that occur due to relatively small changes in ingredient ratios lend further support to the notion that high levels of skill and knowledge were required to consistently produce the most effective adhesives.

  5. Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives

    PubMed Central

    2016-01-01

    The production of compound adhesives using disparate ingredients is seen as some of the best evidence of advanced cognition outside of the use of symbolism. Previous field and laboratory testing of adhesives has shown the complexities involved in creating an effective Middle Stone Age glue using Acacia gum. However, it is currently unclear how efficient different adhesive recipes are, how much specific ingredients influence their performance, and how difficult it may have been for those ingredients to be combined to maximum effect. We conducted a series of laboratory-based lap shear and impact tests, following modern adhesion testing standards, to determine the efficacy of compound adhesives, with particular regard to the ingredient ratios. We tested rosin (colophony) and gum adhesives, containing additives of beeswax and ochre in varying ratios. During both lap shear and impact tests compound rosin adhesives performed better than single component rosin adhesives, and pure acacia gum was the strongest. The large difference in performance between each base adhesive and the significant changes in performance that occur due to relatively small changes in ingredient ratios lend further support to the notion that high levels of skill and knowledge were required to consistently produce the most effective adhesives. PMID:26983080

  6. THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST

    SciTech Connect

    Vandersall, K S; Switzer, L L; Garcia, F

    2006-06-20

    Steven Impact Tests were performed at low velocity on the explosives TNT (trinitrotolulene), Composition B (63% RDX, 36% TNT, and 1% wax by weight), C-4 (91% RDX, 5.3% Di (2-ethylhexyl) sebacate, 2.1% Polyisobutylene, and 1.6% motor oil by weight) and ANFO (94% ammonium Nitrate with 6% Fuel Oil) in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, C-4 or ANFO explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives. These results will also be compared to that of the Susan Test and reaction thresholds observed in the common small-scale safety tests such as the drop hammer and friction tests in hopes of drawing a correlation.

  7. Space Shuttle solid rocket booster initial water impact loads and dynamics - Analysis, tests, and flight experience

    NASA Technical Reports Server (NTRS)

    Kross, D. A.; Kiefling, L. A.; Murphy, N. C.; Rawls, E. A.

    1983-01-01

    A series of scale model tests, finite element dynamic response analyses and full scale segment tests have been performed for purposes of developing design criteria for the initial water impact loading conditions applied to the internal stiffener rings located in the aft skirt portion of the Space Shuttle Solid Rocket Booster (SRB). In addition, flight experience has yielded information relative to structural reinforcement requirements. This paper discusses the test and analysis methods and summarizes significant results. It is noted that, although scale model test data are valuable for identifying trends, they have shortcomings concerning definition of full scale design loads criteria. Also, the frequently used static equivalent loads definition approach is not applicable for this type impact loading condition applied to an aft skirt type structure. Various types of ring structural fixes, including the addition of selected types of foam, are presented as well as associated full scale segment test results. Depending on the type and contour shape of the foam, reductions on applied pressures and peak measured strains over 50 percent are noted.

  8. Statistical variations in impact resistance of steel fiber-reinforced concrete subjected to drop weight test

    SciTech Connect

    Nataraja, M.C.; Dhang, N.; Gupta, A.P.

    1999-07-01

    The variation in impact resistance of steel fiber-reinforced concrete and plain concrete as determined from a drop weight test is reported. The observed coefficients of variation are about 57 and 46% for first-crack resistance and the ultimate resistance in the case of fiber concrete and the corresponding values for plain concrete are 54 and 51%, respectively. The goodness-of-fit test indicated poor fitness of the impact-resistance test results produced in this study to normal distribution at 95% level of confidence for both fiber-reinforced and plain concrete. However, the percentage increase in number of blows from first crack to failure for both fiber-reinforced concrete and as well as plain concrete fit to normal distribution as indicated by the goodness-of-fit test. The coefficient of variation in percentage increase in the number of blows beyond first crack for fiber-reinforced concrete and plain concrete is 51.9 and 43.1%, respectively. Minimum number of tests required to reliably measure the properties of the material can be suggested based on the observed levels of variation.

  9. Quantitative impact characterization of aeronautical CFRP materials with non-destructive testing methods

    NASA Astrophysics Data System (ADS)

    Kiefel, Denis; Stoessel, Rainer; Grosse, Christian

    2015-03-01

    In recent years, an increasing number of safety-relevant structures are designed and manufactured from carbon fiber reinforced polymers (CFRP) in order to reduce weight of airplanes by taking the advantage of their specific strength into account. Non-destructive testing (NDT) methods for quantitative defect analysis of damages are liquid- or air-coupled ultrasonic testing (UT), phased array ultrasonic techniques, and active thermography (IR). The advantage of these testing methods is the applicability on large areas. However, their quantitative information is often limited on impact localization and size. In addition to these techniques, Airbus Group Innovations operates a micro x-ray computed tomography (μ-XCT) system, which was developed for CFRP characterization. It is an open system which allows different kinds of acquisition, reconstruction, and data evaluation. One main advantage of this μ-XCT system is its high resolution with 3-dimensional analysis and visualization opportunities, which enables to gain important quantitative information for composite part design and stress analysis. Within this study, different NDT methods will be compared at CFRP samples with specified artificial impact damages. The results can be used to select the most suitable NDT-method for specific application cases. Furthermore, novel evaluation and visualization methods for impact analyzes are developed and will be presented.

  10. Uniform Foam Crush Testing for Multi-Mission Earth Entry Vehicle Impact Attenuation

    NASA Technical Reports Server (NTRS)

    Patterson, Byron W.; Glaab, Louis J.

    2012-01-01

    Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, four different Rohacell foams are tested at three different, uniform, strain rates (approximately 0.17, approximately 100, approximately 13,600%/s). The primary data analysis method uses a global data smoothing technique in the frequency domain to remove noise and system natural frequencies. The results from the data indicate that the filter and smoothing technique are successful in identifying the foam crush event and removing aberrations. The effect of strain rate increases with increasing foam density. The 71-WF-HT foam may support Mars Sample Return requirements. Several recommendations to improve the drop tower test technique are identified.

  11. Hypervelocity impact testing above 10 km/s of advanced orbital debris shields

    SciTech Connect

    Christiansen, E.L.; Crews, J.L.; Kerr, J.H.; Chhabildas, L.C.

    1996-05-01

    NASA has developed enhanced performance shields to improve the protection of spacecraft from orbital debris and meteoroid impacts. One of these enhanced shields includes a blanket of Nextel{trademark} ceramic fabric and Kevlar{trademark} high strength fabric that is positioned midway between an aluminum bumper and the spacecraft pressure wall. As part of the evaluation of this new shielding technology, impact data above 10 km/sec has been obtained by NASA Johnson Space Center (JSC) from the Sandia National Laboratories HVL ({open_quotes}hypervelocity launcher{close_quotes}) and the Southwest Research Institute inhibited shaped charge launcher (ISCL). The HVL launches flyer-plates in the velocity range of 10 to 15 km/s while the ISCL launches hollow cylinders at {approximately}11.5km/s. The {gt}10km/s experiments are complemented by hydrocode analysis and light-gas gun testing at the JSC Hypervelocity Impact Test Facility (HIT-F) to assess the effects of projectile shape on shield performance. Results from the testing and analysis indicate that the Nextel{trademark}/Kevlar{trademark} shield provides superior protection performance compared to an all-aluminum shield alternative. {copyright} {ital 1996 American Institute of Physics.}

  12. Risk assessment test for lead bioaccessibility to waterfowl in mine-impacted soils

    USGS Publications Warehouse

    Furman, O.; Strawn, D.G.; Heinz, G.H.; Williams, B.

    2006-01-01

    Due to variations in soil physicochemical properties, species physiology, and contaminant speciation, Pb toxicity is difficult to evaluate without conducting in vivo dose-response studies. Such tests, however, are expensive and time consuming, making them impractical to use in assessment and management of contaminated environments. One possible alternative is to develop a physiologically based extraction test (PBET) that can be used to measure relative bioaccessibility. We developed and correlated a PBET designed to measure the bioaccessibility of Pb to waterfowl (W-PBET) in mine-impacted soils located in the Coeur d'Alene River Basin, Idaho. The W-PBET was also used to evaluate the impact of P amendments on Pb bioavailability. The W-PBET results were correlated to waterfowl-tissue Pb levels from a mallard duck [Anas platyrhynchos (L.)] feeding study. The W-PBET Pb concentrations were significantly less in the P-amended soils than in the unamended soils. Results from this study show that the W-PBET can be used to assess relative changes in Pb bioaccessibility to waterfowl in these mine-impacted soils, and therefore will be a valuable test to help manage and remediate contaminated soils.

  13. Quantitative impact characterization of aeronautical CFRP materials with non-destructive testing methods

    SciTech Connect

    Kiefel, Denis E-mail: Rainer.Stoessel@airbus.com; Stoessel, Rainer E-mail: Rainer.Stoessel@airbus.com; Grosse, Christian

    2015-03-31

    In recent years, an increasing number of safety-relevant structures are designed and manufactured from carbon fiber reinforced polymers (CFRP) in order to reduce weight of airplanes by taking the advantage of their specific strength into account. Non-destructive testing (NDT) methods for quantitative defect analysis of damages are liquid- or air-coupled ultrasonic testing (UT), phased array ultrasonic techniques, and active thermography (IR). The advantage of these testing methods is the applicability on large areas. However, their quantitative information is often limited on impact localization and size. In addition to these techniques, Airbus Group Innovations operates a micro x-ray computed tomography (μ-XCT) system, which was developed for CFRP characterization. It is an open system which allows different kinds of acquisition, reconstruction, and data evaluation. One main advantage of this μ-XCT system is its high resolution with 3-dimensional analysis and visualization opportunities, which enables to gain important quantitative information for composite part design and stress analysis. Within this study, different NDT methods will be compared at CFRP samples with specified artificial impact damages. The results can be used to select the most suitable NDT-method for specific application cases. Furthermore, novel evaluation and visualization methods for impact analyzes are developed and will be presented.

  14. Hypervelocity impact testing above 10 km/s of advanced orbital debris shields

    NASA Astrophysics Data System (ADS)

    Christiansen, Eric L.; Crews, Jeanne Lee; Kerr, Justin H.; Chhabildas, Lalit C.

    1996-05-01

    NASA has developed enhanced performance shields to improve the protection of spacecraft from orbital debris and meteoroid impacts. One of these enhanced shields includes a blanket of Nextel™ ceramic fabric and Kevlar™ high strength fabric that is positioned midway between an aluminum bumper and the spacecraft pressure wall. As part of the evaluation of this new shielding technology, impact data above 10 km/sec has been obtained by NASA Johnson Space Center (JSC) from the Sandia National Laboratories HVL ("hypervelocity launcher") and the Southwest Research Institute inhibited shaped charge launcher (ISCL). The HVL launches flyer-plates in the velocity range of 10 to 15 km/s while the ISCL launches hollow cylinders at ˜11.5 km/s. The >10 km/s experiments are complemented by hydrocode analysis and light-gas gun testing at the JSC Hypervelocity Impact Test Facility (HIT-F) to assess the effects of projectile shape on shield performance. Results from the testing and analysis indicate that the Nextel™/Kevlar™ shield provides superior protection performance compared to an all-aluminum shield alternative.

  15. Capabilities of NASA/Marshall Space Flight Center's Impact Testing Facility

    NASA Technical Reports Server (NTRS)

    Hovater, Mary; Hubbs, Whitney; Finchum, Andy; Evans, Steve; Nehls, Mary

    2006-01-01

    The Impact Testing Facility (ITF) serves as an important installation for materials science at Marshall Space Flight Center (MSFC). With an array of air, powder, and two-stage light gas guns, a variety of projectile and target types and sizes can be accommodated. The ITF allows for simulation of impactors from rain to micrometeoroids and orbital debris on materials being investigated for space, atmospheric, and ground use. Expendable, relatively simple launch assemblies are used to obtain well-documented results for impact conditions comparable to those from ballistic and rocket sled ranges at considerably lower cost. In addition, for applications requiring study of impacts at speeds in excess of those attainable by gun launches, hydrocode simulations, validated by test data, can be used to extend the velocity range. In addition to serving various NASA directorates, the ITF has performed testing on behalf of the European and Russian space agencies, as well as the Department of Defense, and academic institutions. The m s contributions not only enable safer space flight for NASA s astronauts, but can help design materials and structures to protect soldiers and civilians on Earth, through advances in body armor, aircraft survivability, and a variety of other applications.

  16. An investigation on impacts of scheduling configurations on Mississippi biology subject area testing

    NASA Astrophysics Data System (ADS)

    Marchette, Frances Lenora

    The purpose of this mixed modal study was to compare the results of Biology Subject Area mean scores of students on a 4 x 4 block schedule, A/B block schedule, and traditional year-long schedule for 1A to 5A size schools. This study also reviewed the data to determine if minority or gender issues might influence the test results. Interviews with administrators and teachers were conducted about the type of schedule configuration they use and the influence that the schedule has on student academic performance on the Biology Subject Area Test. Additionally, this research further explored whether schedule configurations allow sufficient time for students to construct knowledge. This study is important to schools, teachers, and administrators because it can assist them in considering the impacts that different types of class schedules have on student performance and if ethnic or gender issues are influencing testing results. This study used the causal-comparative method for the quantitative portion of the study and constant comparative method for the qualitative portion to explore the relationship of school schedules on student academic achievement on the Mississippi Biology Subject Area Test. The aggregate means of selected student scores indicate that the Mississippi Biology Subject Area Test as a measure of student performance reveals no significant difference on student achievement for the three school schedule configurations. The data were adjusted for initial differences of gender, minority, and school size on the three schedule configurations. The results suggest that schools may employ various schedule configurations and expect student performance on the Mississippi Biology Subject Area Test to be unaffected. However, many areas of concern were identified in the interviews that might impact on school learning environments. These concerns relate to effective classroom management, the active involvement of students in learning, the adequacy of teacher education

  17. Water Impact Test and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Sparks, Chad; Sareen, Ashish

    2003-01-01

    In March 2002, a 25-ft/s vertical drop test of a composite fuselage section was conducted onto water. The purpose of the test was to obtain experimental data characterizing the structural response of the fuselage section during water impact for comparison with two previous drop tests that were performed onto a rigid surface and soft soil. For the drop test, the fuselage section was configured with ten 100-lb. lead masses, five per side, that were attached to seat rails mounted to the floor. The fuselage section was raised to a height of 10-ft. and dropped vertically into a 15-ft. diameter pool filled to a depth of 3.5-ft. with water. Approximately 70 channels of data were collected during the drop test at a 10-kHz sampling rate. The test data were used to validate crash simulations of the water impact that were developed using the nonlinear, explicit transient dynamic codes, MSC.Dytran and LS-DYNA. The fuselage structure was modeled using shell and solid elements with a Lagrangian mesh, and the water was modeled with both Eulerian and Lagrangian techniques. The fluid-structure interactions were executed using the fast general coupling in MSC.Dytran and the Arbitrary Lagrange-Euler (ALE) coupling in LS-DYNA. Additionally, the smooth particle hydrodynamics (SPH) meshless Lagrangian technique was used in LS-DYNA to represent the fluid. The simulation results were correlated with the test data to validate the modeling approach. Additional simulation studies were performed to determine how changes in mesh density, mesh uniformity, fluid viscosity, and failure strain influence the test-analysis correlation.

  18. Design and Analysis of Tooth Impact Test Rig for Spur Gear

    NASA Astrophysics Data System (ADS)

    Ghazali, Wafiuddin Bin Md; Aziz, Ismail Ali Bin Abdul; Daing Idris, Daing Mohamad Nafiz Bin; Ismail, Nurazima Binti; Sofian, Azizul Helmi Bin

    2016-02-01

    This paper is about the design and analysis of a prototype of tooth impact test rig for spur gear. The test rig was fabricated and analysis was conducted to study its’ limitation and capabilities. The design of the rig is analysed to ensure that there will be no problem occurring during the test and reliable data can be obtained. From the result of the analysis, the maximum amount of load that can be applied, the factor of safety of the machine, the stresses on the test rig parts were determined. This is important in the design consideration of the test rig. The materials used for the fabrication of the test rig were also discussed and analysed. MSC Nastran Patran software was used to analyse the model, which was designed by using SolidWorks 2014 software. Based from the results, there were limitations found from the initial design and the test rig design needs to be improved in order for the test rig to operate properly.

  19. Financial impact of a targeted reduction in cardiac enzyme testing at a community hospital

    PubMed Central

    Zhang, Li; Sill, Anne M.; Young, Ilene; Ahmed, Sabreen; Morales, Maria; Kuehl, Sapna

    2016-01-01

    Objectives Nearly one-third of healthcare costs are potentially avoidable and would not compromise medical care if eliminated. Therefore, we sought to evaluate the financial impact of reduction in use of creatinine kinase (CK)-MB and myoglobin tests after removing them from the cardiac enzyme order set at a community hospital. Methods Grand rounds were held, and an email notification was sent to de-emphasize the use of CK, CK-MB, myoglobin, SGOT (glutamic-oxaloacetic transaminase), and SGPT (serum glutamic-pyruvic transaminase) in acute coronary syndrome (ACS) work up. The above tests were removed from the pre-checked cardiac enzyme order set in the computerized physician order entry on February 13, 2014. The tests continued to be available, but needed to be ordered individually. The mean monthly volume of cardiac enzyme tests for 12 months after this intervention was compared with the mean monthly volume of 12 months before the change. Total cost savings were calculated. Results After the intervention, the number of CK, CK-MB, myoglobin, SGOT, and SGPT tests utilized for ACS workup decreased dramatically (p<0.001). The volume of troponin testing remained the same (p=0.283). The total annual savings of billable charges to healthcare payers was $463,744.7. Conclusions Removal of CK-MB, myoglobin, CK, SGOT, and SGPT tests from cardiac enzyme order sets can successfully reduce unnecessary laboratory testing for ACS workup, leading to significant cost savings to the healthcare system. PMID:27802861

  20. An 810 ft/sec soil impact test of a 2-foot diameter model nuclear reactor containment system

    NASA Technical Reports Server (NTRS)

    Puthoff, R. L.

    1972-01-01

    A soil impact test was conducted on a 880-pound 2-foot diameter sphere model. The impact area consisted of back filled desert earth and rock. The impact generated a crater 5 feet in diameter by 5 feet deep. It buried itself a total of 15 feet - as measured to the bottom of the model. After impact the containment vessel was pressure checked. No leaks were detected nor cracks observed.

  1. 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.

  2. Impact dynamics research facility for full-scale aircraft crash testing

    NASA Technical Reports Server (NTRS)

    Vaughan, V. L. J.; Alfaro-Bou, E.

    1976-01-01

    An impact dynamics research facility (IDRF) was developed to crash test full-scale general aviation aircraft under free-flight test conditions. The aircraft are crashed into the impact surface as free bodies; a pendulum swing method is used to obtain desired flight paths and velocities. Flight paths up to -60 deg and aircraft velocities along the flight paths up to about 27.0 m/s can be obtained with a combination of swing-cable lengths and release heights made available by a large gantry. Seven twin engine, 2721-kg aircraft were successfully crash tested at the facility, and all systems functioned properly. Acquisition of data from signals generated by accelerometers on board the aircraft and from external and onboard camera coverage was successful in spite of the amount of damage which occurred during each crash. Test parameters at the IDRF are controllable with flight path angles accurate within 8 percent, aircraft velocity accurate within 6 percent, pitch angles accurate to 4.25 deg, and roll and yaw angles acceptable under wind velocities up to 4.5 m/s.

  3. 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.

  4. Suited and Unsuited Hybrid III Impact Testing and Finite Element Model Characterization

    NASA Technical Reports Server (NTRS)

    Lawrence, C.; Somers, J. T.; Baldwin, M. A.; Wells, J. A.; Newby, N.; Currie, N. J.

    2016-01-01

    NASA spacecraft design requirements for occupant protection are a combination of the Brinkley Dynamic Response Criteria and injury assessment reference values (IARV) extracted from anthropomorphic test devices (ATD). For the ATD IARVs, the requirements specify the use of the 5th percentile female Hybrid III and the 95th percentile male Hybrid III. Each of these ATDs is required to be fitted with an articulating pelvis (also known as the aerospace pelvis) and a straight spine. The articulating pelvis is necessary for the ATD to fit into spacecraft seats, while the straight spine is required as injury metrics for vertical accelerations are better defined for this configuration. Sled testing of the Hybrid III 5th Percentile Female Anthropomorphic Test Device (ATD) was performed at Wright-Patterson Air Force Base (WAPFB). Two 5th Percentile ATDs were tested, the Air Force Research Lab (AFRL) and NASA owned Hybrid III ATDs with aerospace pelvises. Testing was also conducted with a NASA-owned 95th Percentile Male Hybrid III with aerospace pelvis at WPAFB. Testing was performed using an Orion seat prototype provided by Johnson Space Center (JSC). A 5-point harness comprised of 2 inch webbing was also provided by JSC. For suited runs, a small and extra-large Advanced Crew Escape System (ACES) suit and helmet were also provided by JSC. Impact vectors were combined frontal/spinal and rear/lateral. Some pure spinal and rear axis testing was also performed for model validation. Peak accelerations ranged between 15 and 20-g. This range was targeted because the ATD responses fell close to the IARV defined in the Human-Systems Integration Requirements (HSIR) document. Rise times varied between 70 and 110 ms to assess differences in ATD responses and model correlation for different impact energies. The purpose of the test series was to evaluate the Hybrid III ATD models in Orion-specific landing orientations both with and without a spacesuit. The results of these tests were used

  5. Impact toughness of irradiated reduced-activation ferritic steels*1

    NASA Astrophysics Data System (ADS)

    Klueh, R. L.; Alexander, D. J.

    1994-09-01

    Eight chromium-tungsten steels ranging from 2.25 to 12 wt% Cr were irradiated at 365°C to 13-14 dpa in the Fast Flux Test Facility. Post irradiation Charpy impact tests showed a loss of toughness for all steels, as measured by an increase in the ductile-brittle transition temperature (DBTT) and a decrease in the upper-shelf energy. The most irradiation-resistant steels were two 9% Cr steels: the DBTT of a 9Cr-2W-0.25V-0.1C steel increased 29°C, and for the same composition with an addition of 0.07% Ta the DBTT increased only 15°C. This is the smallest shift ever observed for such a steel irradiated to these levels. The other steels developed shifts in DBTT of 100 to 300°C. A 2.25% Cr steel with 2% W, 0.25% V, and 0.1% C was less severely affected by irradiation than 2.25% Cr steels with 0.25% V and no tungsten, 2% W and no vanadium, and with 1% W and 0.25% V. Irradiation resistance appears to be associated with microstructure, and microstructural manipulation may lead to improved properties.

  6. Testing, Modeling and System Impact of Metabolic Heat Regenerated Temperature Swing Adsorption

    NASA Technical Reports Server (NTRS)

    Lacomini, Christine S.; Powers, Aaron; Lewis, Matthew; Linrud, Christopher; Waguespack, Glenn; Conger, Bruce; Paul, Heather L.

    2008-01-01

    Metabolic heat regenerated temperature swing adsorption (MTSA) technology is being developed for removal and rejection of carbon dioxide (CO2) and heat from a portable life support system (PLSS) to the Martian environment. Previously, hardware was built and tested to demonstrate using heat from simulated, dry ventilation loop gas to affect the temperature swing required to regenerate an adsorbent used for CO2 removal. New testing has been performed using a moist, simulated ventilation loop gas to demonstrate the effects of water condensing and freezing in the heat exchanger during adsorbent regeneration. In addition, thermal models of the adsorbent during regeneration were modified and calibrated with test data to capture the effect of the CO2 heat of desorption. Finally, MTSA impact on PLSS design was evaluated by performing thermal balances assuming a specific PLSS architecture. Results using NASA s Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT), a PLSS system evaluation tool, are presented.

  7. Flight test experience and controlled impact of a large, four-engine, remotely piloted airplane

    NASA Technical Reports Server (NTRS)

    Kempel, R. W.; Horton, T. W.

    1985-01-01

    A controlled impact demonstration (CID) program using a large, four engine, remotely piloted transport airplane was conducted. Closed loop primary flight control was performed from a ground based cockpit and digital computer in conjunction with an up/down telemetry link. Uplink commands were received aboard the airplane and transferred through uplink interface systems to a highly modified Bendix PB-20D autopilot. Both proportional and discrete commands were generated by the ground pilot. Prior to flight tests, extensive simulation was conducted during the development of ground based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems. However, manned flight tests were the primary method of verification and validation of control law concepts developed from simulation. The design, development, and flight testing of control laws and the systems required to accomplish the remotely piloted mission are discussed.

  8. Flight test experience and controlled impact of a large, four-engine remotely piloted airplane

    NASA Technical Reports Server (NTRS)

    Kempel, R. W.; Horton, T. W.

    1985-01-01

    A controlled impact demonstration (CID) program using a large, four engine, remotely piloted transport airplane was conducted. Closed loop primary flight control was performed from a ground based cockpit and digital computer in conjunction with an up/down telemetry link. Uplink commands were received aboard the airplane and transferred through uplink interface systems to a highly modified Bendix PB-20D autopilot. Both proportional and discrete commands were generated by the ground pilot. Prior to flight tests, extensive simulation was conducted during the development of ground based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems. However, manned flight tests were the primary method of verification and validation of control law concepts developed from simulation. The design development, and flight testing of control laws and the systems required to accomplish the remotely piloted mission are discussed.

  9. Impact of the emergence of designer drugs upon sports doping testing.

    PubMed

    Teale, P; Scarth, J; Hudson, S

    2012-01-01

    Historically, dope-testing methods have been developed to target specific and known threats to the integrity of sport. Traditionally, the source of new analytical targets for which testing was required were derived almost exclusively from the pharmaceutical industry. More recently, the emergence of designer drugs, such as tetrahydrogestrinone that are specifically intended to evade detection, or novel chemicals intended to circumvent laws controlling the sale and distribution of recreational drugs, such as anabolic steroids, stimulants and cannabinoids, have become a significant issue. In this review, we shall consider the emergence of designer drugs and the response of dope-testing laboratories to these new threats, in particular developments in analytical methods, instrumentation and research intended to detect their abuse, and we consider the likely future impact of these approaches.

  10. A framework for predicting the yield stress, Charpy toughness and one hundred-year activation level for irradiated fusion power plant alloys

    NASA Astrophysics Data System (ADS)

    Windsor, Colin; Cottrell, Geoff; Kemp, Richard

    2011-04-01

    Recent papers have demonstrated that the yield stress and the Charpy ductile to brittle transition temperature shift at the high irradiation levels of a fusion power plant may be predicted from measurements at lower irradiation levels using neural networks. It was demonstrated that the extrapolation inherent in such predictions could be validated provided that network complexity was appropriately low. Simultaneous predictions of these metallurgical properties at the 100 dpa irradiation level and 400 °C irradiation temperature of a possible fusion power plant have been made for a series of ferritic/martensitic steels, albeit based on mainly fission data. Together with the readily available one hundred-year activation level, benefit functions are defined which can be used to predict the most suitable alloys for a fusion power plant from within existing databases. Our model is sufficiently flexible to allow a variety of possible benefit functions to be defined. The F82H, Eurofer and LA12 alloy series all receive a favourable rating, although all results presented here must be tempered with caution until more data at relevant irradiation levels and with relevant energy spectra become available.

  11. Experimental and numerical analysis of Izod impact test of cortical bone tissue

    NASA Astrophysics Data System (ADS)

    Abdel-Wahab, A. A.; Silberschmidt, V. V.

    2012-05-01

    Bones can only sustain loads until a certain limit, beyond which they fail. Usually, the reasons for bone fracture are traumatic falls, sports injuries, and engagement in transport or industrial accidents. A proper treatment of bones and prevention of their fracture can be supported by in-depth understanding of deformation and fracture behavior of this tissue in such dynamic events. In this paper, a combination of experimental and numerical analysis was carried out in order to comprehend the fracture behavior of cortical bone tissue. Experimental tests were performed to study the transient dynamic behavior of cortical bone tissue under impact bending loading. The variability of absorbed energy for different cortex positions and notch depths was studied using Izod impact tests. Also, Extended Finite-Element Method implemented into the commercial finite-element software Abaqus was used to simulate the crack initiation and growth processes in a cantilever beam of cortical bone exposed to impact loading using the Izod loading scheme. The simulation results show a good agreement with the experimental data.

  12. Hypervelocity impact testing of advanced materials and structures for micrometeoroid and orbital debris shielding

    NASA Astrophysics Data System (ADS)

    Ryan, Shannon; Christiansen, Eric L.

    2013-02-01

    A series of 66 hypervelocity impact experiments have been performed to assess the potential of various materials (aluminium, titanium, copper, stainless steel, nickel, nickel/chromium, reticulated vitreous carbon, silver, ceramic, aramid, ceramic glass, and carbon fibre) and structures (monolithic plates, open-cell foam, flexible fabrics, rigid meshes) for micrometeoroid and orbital debris (MMOD) shielding. Arranged in various single-, double-, and triple-bumper configurations, screening tests were performed with 0.3175 cm diameter Al2017-T4 spherical projectiles at nominally 6.8 km/s and normal incidence. The top performing shields were identified through target damage assessments and their respective weight. The top performing candidate shield at the screening test condition was found to be a double-bumper configuration with a 0.25 mm thick Al3003 outer bumper, 6.35 mm thick 40 PPI aluminium foam inner bumper, and 1.016 mm thick Al2024-T3 rear wall (equal spacing between bumpers and rear wall). In general, double-bumper candidates with aluminium plate outer bumpers and foam inner bumpers were consistently found to be amongst the top performers. For this impact condition, potential weight savings of at least 47% over conventional all-aluminium Whipple shields are possible by utilizing the investigated materials and structures. The results of this study identify materials and structures of interest for further, more in-depth, impact investigations.

  13. Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test

    SciTech Connect

    Switzer, L L; Vandersall, K S; Chidester, S K; Greenwood, D W; Tarver, C M

    2003-07-01

    Impact tests performed at low velocity on heated energetic material samples are of interest when considering the situation of energetic materials involved in a fire. To determine heated reaction thresholds, Steven Test targets containing PBX 9404 or LX-04 samples heated to the range of 150-170 C were impacted at velocities up to 150 m/s by two different projectile head geometries. Comparing these measured thresholds to ambient temperature thresholds revealed that the heated LX-04 thresholds were considerably higher than ambient, whereas the heated PBX 9404 thresholds were only slightly higher than the ambient temperature thresholds. The violence of reaction level of the PBX 9404 was considerably higher than that of the LX-04 as measured with four overpressure gauges. The varying results in these samples with different HMX/binder configurations indicate that friction plays a dominant role in reaction ignition during impact. This work outlines the experimental details, compares the thresholds and violence levels of the heated and ambient temperature experiments, and discusses the dominant mechanisms of the measured thresholds.

  14. Fibre optic sensors for high speed hypervelocity impact studies and low velocity drop tests

    NASA Astrophysics Data System (ADS)

    Jackson, D. A.; Cole, M. J.; Burchell, M. J.; Webb, D. J.

    2011-05-01

    The initial aim of this project was to develop a non-contact fibre optic based displacement sensor to operate in the harsh environment of a 'Light Gas Gun' (LGG), which can 'fire' small particles at velocities ranging from 1-8.4 km/s. The LGG is used extensively for research in aerospace to analyze the effects of high speed impacts on materials. Ideally the measurement should be made close to the centre of the impact to minimise corruption of the data from edge effects and survive the impact. A further requirement is that it should operate at a stand-off distance of ~ 8cm. For these reasons we chose to develop a pseudo con-focal intensity sensor, which demonstrated resolution comparable with conventional PVDF sensors combined with high survivability and low cost. A second sensor was developed based on 'Fibre Bragg Gratings' (FBG) which although requiring contact with the target the low weight and very small contact area had minimal effect on the dynamics of the target. The FBG was mounted either on the surface of the target or tangentially between a fixed location. The output signals from the FBG were interrogated in time by a new method. Measurements were made on composite and aluminium plates in the LGG and on low speed drop tests. The particle momentum for the drop tests was chosen to be similar to that of the particles used in the LGG.

  15. Ubiquitous testing using tablets: its impact on medical student perceptions of and engagement in learning

    PubMed Central

    Kim, Kyong-Jee; Hwang, Jee-Young

    2016-01-01

    Purpose: Ubiquitous testing has the potential to affect medical education by enhancing the authenticity of the assessment using multimedia items. This study explored medical students’ experience with ubiquitous testing and its impact on student learning. Methods: A cohort (n=48) of third-year students at a medical school in South Korea participated in this study. The students were divided into two groups and were given different versions of 10 content-matched items: one in text version (the text group) and the other in multimedia version (the multimedia group). Multimedia items were delivered using tablets. Item response analyses were performed to compare item characteristics between the two versions. Additionally, focus group interviews were held to investigate the students’ experiences of ubiquitous testing. Results: The mean test score was significantly higher in the text group. Item difficulty and discrimination did not differ between text and multimedia items. The participants generally showed positive responses on ubiquitous testing. Still, they felt that the lectures that they had taken in preclinical years did not prepare them enough for this type of assessment and clinical encounters during clerkships were more helpful. To be better prepared, the participants felt that they needed to engage more actively in learning in clinical clerkships and have more access to multimedia learning resources. Conclusion: Ubiquitous testing can positively affect student learning by reinforcing the importance of being able to understand and apply knowledge in clinical contexts, which drives students to engage more actively in learning in clinical settings. PMID:26838569

  16. Tests to evaluate the ecological impact of treated ballast water on three Chinese marine species

    NASA Astrophysics Data System (ADS)

    Zhang, Yanan; Wang, Zixi; Cai, Leiming; Cai, Xiang; Sun, Wenjun; Ma, Liqing

    2014-09-01

    Ballast water has been a topic of concern for some time because of its potential to introduce invasive species to new habitats. To comply with the International Convention for the Control and Management of Ships' Ballast Water and Sediments, members of the International Maritime Organization (IMO) must equip their ships with on-board treatment systems to eliminate organism release with ballast water. There are many challenges associated with the implementation of this IMO guideline, one of which is the selection of species for testing the ecological impacts of the treated ballast water. In the United States, ballast water toxicity test methods have been defined by the United States Environmental Protection Agency. However, the test methods had not been finalized in China until the toxicity test methods for ballast water were established in 2008. The Chinese methods have been based on species from three trophic levels: Skeletonema costatum, Neomysis awatschensis, and Ctenogobius gymnauchen. All three species live in broad estuarine and open sea areas of China; they are sensitive to reference toxicants and acclimatize easily to different conditions. In this paper, the biological characteristics, test processes and statistical analysis methods are presented for the three species. Results indicate that the methods for evaluating these three organisms can be included in the ecological toxicity tests for treated ballast water in China.

  17. BRCA1/2 test results impact risk management attitudes, intentions, and uptake.

    PubMed

    O'Neill, Suzanne C; Valdimarsdottir, Heiddis B; Demarco, Tiffani A; Peshkin, Beth N; Graves, Kristi D; Brown, Karen; Hurley, Karen E; Isaacs, Claudine; Hecker, Sharon; Schwartz, Marc D

    2010-12-01

    Women who receive positive or uninformative BRCA1/2 test results face a number of decisions about how to manage their cancer risk. The purpose of this study was to prospectively examine the effect of receiving a positive versus uninformative BRCA1/2 genetic test result on the perceived pros and cons of risk-reducing mastectomy (RRM) and risk-reducing oophorectomy (RRO) and breast cancer screening. We further examined how perceived pros and cons of surgery predict intention for and uptake of surgery. 308 women (146 positive, 162 uninformative) were included in RRM and breast cancer screening analyses. 276 women were included in RRO analyses. Participants completed questionnaires at pre-disclosure baseline and 1-, 6-, and 12-months post-disclosure. We used linear multiple regression to assess whether test result contributed to change in pros and cons and logistic regression to predict intentions and surgery uptake. Receipt of a positive BRCA1/2 test result predicted stronger pros for RRM and RRO (P < 0.001), but not perceived cons of RRM and RRO. Pros of surgery predicted RRM and RRO intentions in carriers and RRO intentions in uninformatives. Cons predicted RRM intentions in carriers. Pros and cons predicted carriers' RRO uptake in the year after testing (P < 0.001). Receipt of BRCA1/2 mutation test results impacts how carriers see the positive aspects of RRO and RRM and their surgical intentions. Both the positive and negative aspects predict uptake of surgery.

  18. Impact of gene patents on diagnostic testing: a new patent landscaping method applied to spinocerebellar ataxia

    PubMed Central

    Berthels, Nele; Matthijs, Gert; Van Overwalle, Geertrui

    2011-01-01

    Recent reports in Europe and the United States raise concern about the potential negative impact of gene patents on the freedom to operate of diagnosticians and on the access of patients to genetic diagnostic services. Patents, historically seen as legal instruments to trigger innovation, could cause undesired side effects in the public health domain. Clear empirical evidence on the alleged hindering effect of gene patents is still scarce. We therefore developed a patent categorization method to determine which gene patents could indeed be problematic. The method is applied to patents relevant for genetic testing of spinocerebellar ataxia (SCA). The SCA test is probably the most widely used DNA test in (adult) neurology, as well as one of the most challenging due to the heterogeneity of the disease. Typically tested as a gene panel covering the five common SCA subtypes, we show that the patenting of SCA genes and testing methods and the associated licensing conditions could have far-reaching consequences on legitimate access to this gene panel. Moreover, with genetic testing being increasingly standardized, simply ignoring patents is unlikely to hold out indefinitely. This paper aims to differentiate among so-called ‘gene patents' by lifting out the truly problematic ones. In doing so, awareness is raised among all stakeholders in the genetic diagnostics field who are not necessarily familiar with the ins and outs of patenting and licensing. PMID:21811306

  19. Relationships between seat properties and human subject kinematics in rear impact tests.

    PubMed

    Welcher, J B; Szabo, T J

    2001-05-01

    The mitigation of whiplash associated disorders (WAD) has received increased priority in the last 10 years. Although the exact mechanism(s) for WAD causation have not been established, several have been proposed and it is likely the mechanism(s) are associated with the kinematics of the head relative to the torso. It follows that automotive seat designs that address reductions in certain head-torso kinematics may lead to a reduction in WAD potential. Seat properties that may have an effect on head-neck kinematics include geometry, stiffness and energy absorption. This study evaluated the performance of five seats with varying properties, including the new Volvo 'WHIPS' seat. Seat properties such as geometry relative to the occupant's head, dynamic and static stiffness, and energy absorption were determined via component testing. A new prototype dynamic seat test, which used a pendulum and seat back pan, was evaluated. Human subject impact tests were conducted using three occupants in rear impacts with velocity changes of 4 and 8 km/h. Potentially relevant occupant kinematic parameters were identified, and then correlated with seat properties in an attempt to determine any relative influence of seat properties on potential WAD mechanisms. Two higher velocity human subject tests using the Volvo Whiplash Injury Protection System (WHIPS) seat were also conducted. Vertical and horizontal head to head restraint distances were found to be most influential on occupant head-neck kinematics. Horizontal and vertical head to head restraint offsets were significantly correlated with rearward translational motion of the head center of gravity relative to the upper torso across all occupants. Rearward offset was also significantly correlated with rearward rotation of the head relative to upper torso, while vertical offset was significantly correlated with head acceleration relative to the upper torso during the flexion phase of the impact. Seat constitutive properties such as

  20. Test and Analysis Correlation of Form Impact onto Space Shuttle Wing Leading Edge RCC Panel 8

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Lyle, Karen H.; Gabrys, Jonathan; Melis, Matthew; Carney, Kelly

    2004-01-01

    Soon after the Columbia Accident Investigation Board (CAIB) began their study of the space shuttle Columbia accident, "physics-based" analyses using LS-DYNA were applied to characterize the expected damage to the Reinforced Carbon-Carbon (RCC) leading edge from high-speed foam impacts. Forensic evidence quickly led CAIB investigators to concentrate on the left wing leading edge RCC panels. This paper will concentrate on the test of the left-wing RCC panel 8 conducted at Southwest Research Institute (SwRI) and the correlation with an LS-DYNA analysis. The successful correlation of the LS-DYNA model has resulted in the use of LS-DYNA as a predictive tool for characterizing the threshold of damage for impacts of various debris such as foam, ice, and ablators onto the RCC leading edge for shuttle return-to-flight.

  1. A Gas-Actuated Projectile Launcher for High-Energy Impact Testing of Structures

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Jaunky, Navin; Lawson, Robin E.; Knight, Norman F., Jr.; Lyle, Karen H.

    1999-01-01

    A gas-act,uated penetration device has been developed for high-energy impact testing of structures. The high-energy impact. t,estiiig is for experimental simulation of uncontained engine failures. The non-linear transient finite element, code LS-DYNA3D has been used in the numerical simula.tions of a titanium rectangular blade with a.n aluminum target, plate. Threshold velocities for different combinations of pitch and yaw angles of the impactor were obtained for the impactor-target, t8est configuration in the numerica.1 simulations. Complet,e penet,ration of the target plate was also simulat,ed numerically. Finally, limited comparison of analytical and experimental results is presented for complete penetration of the target by the impactor.

  2. A 640 foot per second impact test of a two foot diameter model nuclear reactor containment system without fracture

    NASA Technical Reports Server (NTRS)

    Puthoff, R. L.

    1971-01-01

    An impact test was conducted on an 1142 pound 2 foot diameter sphere model. The purpose of this test was to determine the feasibility of containing the fission products of a mobile reactor in an impact. The model simulated the reactor core, energy absorbing gamma shielding, neutron shielding and the containment vessel. It was impacted against an 18,000 pound reinforced concrete block. The model was significantly deformed and the concrete block demolished. No leaks were detected nor cracks observed in the model after impact.

  3. Model Investigation of Technique for Full Scale Landing Impact Tests at Simulated Lunar Gravity

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Model Investigation of Technique for Full Scale Landing Impact Tests at Simulated Lunar Gravity. An investigation of a 1/6-scale dynamic model has been made to develop and evaluate a technique for conducting full-scale landing-impact tests at simulated lunar gravity. Landings were made at touchdown pitch attitudes of -15 degrees, 0 degrees, and 15 degrees. All landings were made with two gear pads forward and at a roll attitude of 0 degrees. Both roll and yaw attitudes were constrained. Vertical landing speed was varied from 5 to 15 feet per second (1.5 to 4.6 m/s) and horizontal speed was varied from 0 to 10 feet per second (0 to 3.0 m/s). Most of the landings were made at a vertical and horizontal speed of 10 feet per second or 3.0 m/s (45 degree flight-path angle) while pitch attitude and surface characteristics, friction and topography, were varied. These parameters were investigated with the free-body earth-gravity and the simulated lunar-gravity test techniques. The landings were made at a model mass corresponding to a full-scale lunar weight (force due to gravity) of 1,440 pounds (6.41 kN) or an earth weight of 8,640 pounds (38.4 kN). [Entire movie available on DVD from CASI as Doc ID 20070030977. Contact help@sti.nasa.gov

  4. LX-04 Violence Measurments: Steven Tests Impacted By Projectiles Shot From A Howitzer Gun

    NASA Astrophysics Data System (ADS)

    Chidester, Steven K.

    2005-07-01

    Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 150-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04 has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence. This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

  5. Hybrid III Lower Leg Injury Assessment Reference Curves Under Axial Impacts Using Matched-Pair Tests.

    PubMed

    Yoganandan, Narayan; Pintar, Frank; Banerjee, Anjishnu; Schlick, Michael; Chirvi, Sajal; Uppal, Hermeeth; Merkle, Andrew; Voo, Liming; Kleinberg, Michael

    2015-01-01

    The objective of the present study was to derive injury probability curves applicable to the Hybrid III dummy (also termed the Anthropomorphic Test Device, ATD) lower leg under axial impacts for military applications. A matched-pair approach was used. Axial impacts were delivered to below knee foot-ankle complex preparations of the lower leg of the ATD using pendulum and custom vertical accelerator devices. Military boot was used in some tests. Post mortem human surrogate (PMHS) preparations were used as matched-pair tests for injury outcomes. The alignment was such that the foot-ankle complex was orthogonal to the leg (below knee tibia-fibula complex), termed as the normal 90-90 posture. Injury outcomes from the biological surrogate focused on calcaneus and or distal tibia fractures with or without the involvement of articular surfaces. Peak lower tibia load cell forces were obtained from matched-pair dummy tests. Injury and force data were paired, censoring was assigned based on injury outcomes and survival analysis was done using the Weibull distribution to derive dummy-based probability curves. Mean peak forces were extracted at 5, 10, 20 and 50% probability levels. Normalized confidence interval sizes (NCIS) at ± 95% level were computed to determine the tightness-of-fit of the confidence bands. The NCIS data ranged from 0.34 to 0.78 and a peak force of 8.2 kN was associated at the ten percent injury probability level. Other data and curves are given in the body of the paper. The present Injury Assessment Reference Curves and Values (IARC and IARV) may be used in future tests for advancing safety in military environments. These survival analysis processes and IARC and IARV data may also be used in other applications.

  6. Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

    NASA Technical Reports Server (NTRS)

    Hernandez, Sonia; Barbee, Brent W.

    2011-01-01

    There are currently over 8,000 known near-Earth asteroids (NEAs), and more are being discovered on a continual basis. More than 1,200 of these are classified as Potentially Hazardous Asteroids (PHAs) because their Minimum Orbit Intersection Distance (MOID) with Earth's orbit is <= 0.05 AU and their estimated diameters are >= 150 m. To date, 178 Earth impact structures have been discovered, indicating that our planet has previously been struck with devastating force by NEAs and will be struck again. Such collisions are aperiodic events and can occur at any time. A variety of techniques have been proposed to defend our planet from NEA impacts by deflecting the incoming asteroid. However, none of these techniques have been tested. Unless rigorous testing is conducted to produce reliable asteroid deflection systems, we will be forced to deploy completely untested -- and therefore unreliable -- deflection missions when a sizable asteroid on a collision course with Earth is discovered. Such missions will have a high probability of failure. We propose to address this problem with a campaign of deflection technology test missions deployed to harmless NEAs. The objective of these missions is to safely evaluate and refine the mission concepts and asteroid deflection system designs. Our current research focuses on the kinetic impactor, one of the simplest proposed asteroid deflection techniques in which a spacecraft is sent to collide with an asteroid at high relative velocity. By deploying test missions in the near future, we can characterize the performance of this deflection technique and resolve any problems inherent to its execution before needing to rely upon it during a true emergency. In this paper we present the methodology and results of our survey, including lists of NEAs for which safe and effective kinetic impactor test missions may be conducted within the next decade. Full mission designs are also presented for the NEAs which offer the best mission opportunities.

  7. Pressure scaled water impact test of a 12.5 inch diameter model of the Space Shuttle solid rocket booster

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A total of 59 tail first drops were made. Model entry conditions simulated full scale vertical velocities of approximately 75 to 110 ft/sec with horizontal velocities up to 45 ft/sec and impact angles to + or - 10 deg. These tests were conducted at scaled atmospheric pressures (1.26 psia or 65 mm.Hg). The model, test program, test facility, test equipment, instrumentation system, data reduction procedures, and test results are described.

  8. Retrospective evaluation of the impact of functional immunotoxicity testing on pesticide hazard identification and risk assessment.

    PubMed

    Gehen, Sean C; Blacker, Ann M; Boverhof, Darrell R; Hanley, Thomas R; Hastings, Charles E; Ladics, Gregory S; Lu, Haitian; O'Neal, Fredrick O

    2014-05-01

    Conduct of a T-cell-dependent antibody response (TDAR) assay in rodents according to Environmental Protection Agency (EPA) Test Guideline OPPTS 870.7800 is now required for chemical pesticide active ingredients registered in the United States. To assess potential regulatory impact, a retrospective analysis was developed using TDAR tests conducted on 78 pesticide chemicals from 46 separate chemical classes. The objective of the retrospective analysis was to examine the frequency of positive responses and determine the potential for the TDAR to yield lower endpoints than those utilized to calculate reference doses (RfDs). A reduction in the TDAR response was observed at only the high-dose level in five studies, while it was unaltered in the remaining studies. Importantly, for all 78 pesticide chemicals, the TDAR no-observed-adverse-effect levels (TDAR NOAELs) were greater than the NOAELS currently in use as risk assessment endpoints. The TDAR NOAELs were higher than the current EPA-selected endpoints for the chronic RfD, short-term, intermediate and long-term exposure scenarios by 3-27,000, 3-1,688, 3-1,688 and 4.9-1,688 times, respectively. Based on this analysis, conduct of the TDAR assay had minimal impact on hazard identification and did not impact human health risk assessments for the pesticides included in this evaluation. These data strongly support employment of alternative approaches including initial weight-of-evidence analysis for immunotoxic potential prior to conducting functional immunotoxicity testing for pesticide active ingredients.

  9. Vehicle Impact Testing of Snow Roads at McMurdo Station, Antarctica

    DTIC Science & Technology

    2014-06-01

    McMurdo Station, Antarctica Co ld R eg io ns R es ea rc h an d En gi ne er in g La bo ra to ry Sally A. Shoop, Margaret A. Knuth, Wendy L...Vehicle Impact Testing of Snow Roads at McMurdo Station, Antarctica Sally A. Shoop, Margaret A. Knuth, and Monica Preston Cold Regions Research and...kilograms ERDC/CRREL TR-14-9 xii ERDC/CRREL TR-14-9 1 1 Introduction 1.1 Issue McMurdo Station, Antarctica , has approximately 20 miles (32 km

  10. An experimental study of the self-healing behavior of ionomeric systems under ballistic impact tests

    NASA Astrophysics Data System (ADS)

    Grande, A. M.; Coppi, S.; Di Landro, L.; Sala, G.; Giacomuzzo, C.; Francesconi, A.; Rahman, M. A.

    2012-04-01

    This research deals with the investigation of the self-healing behavior after ballistic damage of ethylene-methacrylic acid ionomers and theirs blends with epoxidized natural rubber (ENR). The self-healing capability was studied by ballistic puncture tests under different experimental conditions as sample thickness, bullet speed, diameter and shape. Bullet speed ranging from few hundreds meters per second to few km/s were employed. The healing efficiency was evaluated by applying a pressure gradient trough the plates and by checking for possible flow at the damage zone. A morphology analysis of the impact area was made observing all samples by scanning electron microscope.

  11. Testing the impact on natural risks' awareness of visual communication through an exhibition

    NASA Astrophysics Data System (ADS)

    Charrière, Marie; Bogaard, Thom; Junier, Sandra; Malet, Jean-Philippe; Mostert, Erik

    2014-05-01

    The need to communicate about natural disasters in order to improve the awareness of communities at risk is not a matter for debate anymore. However, communication can be implemented using different media and tools, and their effectiveness may be difficult to grasp. Current research on the topic is usually focused on assessing whether communication practices meet users' needs, whereas impact assessment is mostly left out. It can be explained by difficulties arising from (1) the definition of the impact to measure, i.e. awareness, and the appropriate indicators to measure it and its variations, and (2) the implementation of a research design that allows assessing these impacts without bias. This research aims at both developing a methodology to measure risk awareness and to use it for testing the effectiveness of visual communication. The testing was conducted in the Ubaye Valley in France, an alpine area affected by multiple hazards, from December 2013 to mid-February 2014. The setting consisted of an exhibition in the public library of the main town, Barcelonnette. The main natural hazards of the study case (i.e. landslides, avalanches, flooding, debris flows and earthquakes), as well as structural and non-structural measures were presented to the general public using local examples of hazards events and mitigation. Various visualization tools were used: videos, Google earth map, interactive timeline, objects, mock-ups, technical devices as well as posters with pictures, drawings and graphs. In order to assess the effects of the exhibition on risk awareness, several groups of children and adults were submitted to a research design, consisting of 1) a pre-test, 2) the visit of the exhibition and 3) a post-test similar to the pre-test. Close-ended questions addressed the awareness indicators according to the literature, i.e. worry level, previous experiences with natural hazards events, exposure to awareness raising, ability to mitigate/respond/prepare, attitude to

  12. Closure Report for Corrective Action Unit 107: Low Impact Soil Sites, Nevada Test Site, Nevada

    SciTech Connect

    NSTec Environmental Restoration

    2009-06-01

    Corrective Action Unit (CAU) 107 is identified in the Federal Facility Agreement and Consent Order (FFACO) as 'Low Impact Soil Sites' and consists of the following 15 Corrective Action Sites (CASs), located in Areas 1, 2, 3, 4, 5, 9, 10, and 18 of the Nevada Test Site: CAS 01-23-02, Atmospheric Test Site - High Alt; CAS 02-23-02, Contaminated Areas (2); CAS 02-23-03, Contaminated Berm; CAS 02-23-10, Gourd-Amber Contamination Area; CAS 02-23-11, Sappho Contamination Area; CAS 02-23-12, Scuttle Contamination Area; CAS 03-23-24, Seaweed B Contamination Area; CAS 03-23-27, Adze Contamination Area; CAS 03-23-28, Manzanas Contamination Area; CAS 03-23-29, Truchas-Chamisal Contamination Area; CAS 04-23-02, Atmospheric Test Site T4-a; CAS 05-23-06, Atmospheric Test Site; CAS 09-23-06, Mound of Contaminated Soil; CAS 10-23-04, Atmospheric Test Site M-10; and CAS 18-23-02, U-18d Crater (Sulky). Closure activities were conducted from February through April 2009 according to the FFACO (1996; as amended February 2008) and Revision 1 of the Streamlined Approach for Environmental Restoration Plan for CAU 107 (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, 2009). The corrective action alternatives included No Further Action and Closure in Place with Administrative Controls. Closure activities are summarized.

  13. Analytical impact models and experimental test validation for the Columbia shuttle wing leading edge panels.

    SciTech Connect

    Lu, Wei-Yang; Metzinger, Kurt Evan; Gwinn, Kenneth West; Antoun, Bonnie R.; Korellis, John S.

    2004-10-01

    This paper describes the analyses and the experimental mechanics program to support the National Aeronautics and Space Administration (NASA) investigation of the Shuttle Columbia accident. A synergism of the analysis and experimental effort is required to insure that the final analysis is valid - the experimental program provides both the material behavior and a basis for validation, while the analysis is required to insure the experimental effort provides behavior in the correct loading regime. Preliminary scoping calculations of foam impact onto the Shuttle Columbia's wing leading edge determined if enough energy was available to damage the leading edge panel. These analyses also determined the strain-rate regimes for various materials to provide the material test conditions. Experimental testing of the reinforced carbon-carbon wing panels then proceeded to provide the material behavior in a variety of configurations and strain-rates for flown or conditioned samples of the material. After determination of the important failure mechanisms of the material, validation experiments were designed to provide a basis of comparison for the analytical effort. Using this basis, the final analyses were used for test configuration, instrumentation location, and calibration definition in support of full-scale testing of the panels in June 2003. These tests subsequently confirmed the accident cause.

  14. HIV testing and counselling in Estonian prisons, 2012 to 2013: aims, processes and impacts.

    PubMed

    Kivimets, K; Uuskula, A

    2014-11-27

    We present data from an observational cohort study on human immunodeficiency virus (HIV) prevention and control measures in prisons in Estonia to assess the potential for HIV transmission in this setting. HIV testing and retesting data from the Estonian prison health department were used to estimate HIV prevalence and incidence in prison. Since 2002, voluntary HIV counselling and testing has routinely been offered to all prisoners and has been part of the new prisoners health check. At the end of 2012, there were 3,289 prisoners in Estonia, including 170 women: 28.5% were drug users and 15.6% were infected with HIV. Of the HIV-positive inmates, 8.3% were newly diagnosed on prison entry. In 2012, 4,387 HIV tests (including retests) were performed in Estonian prisons. Among 1,756 initially HIV-negative prisoners who were in prison for more than one year and therefore tested for HIV twice within 12 months (at entry and annual testing), one new HIV infection was detected, an incidence of 0.067 per 100 person-years (95% confidence interval (CI): 0.025–5.572). This analysis indicates low risk of HIV transmission in Estonian prisons. Implementation of HIV management interventions could impact positively on the health of prisoners and the communities to which they return.

  15. Assessing the Impact of Testing Aids on Post-Secondary Student Performance: A Meta-Analytic Investigation

    ERIC Educational Resources Information Center

    Larwin, Karen H.; Gorman, Jennifer; Larwin, David A.

    2013-01-01

    Testing aids, including student-prepared testing aids (a.k.a., cheat sheets or crib notes) and open-textbook exams, are common practice in post-secondary assessment. There is a considerable amount of published research that discusses and investigates the impact of these testing aids. However, the findings of this research are contradictory and…

  16. The Impact of Escape Alternative Position Change in Multiple-Choice Test on the Psychometric Properties of a Test and Its Items Parameters

    ERIC Educational Resources Information Center

    Hamadneh, Iyad Mohammed

    2015-01-01

    This study aimed at investigating the impact changing of escape alternative position in multiple-choice test on the psychometric properties of a test and it's items parameters (difficulty, discrimination & guessing), and estimation of examinee ability. To achieve the study objectives, a 4-alternative multiple choice type achievement test…

  17. Instrumented impact properties of zircaloy-oxygen and zircaloy-hydrogen alloys

    SciTech Connect

    Garde, A.M.; Kassner, T.F.

    1980-04-01

    Instrumented-impact tests were performed on subsize Charpy speciments of Zircaloy-2 and -4 with up to approx. 1.3 wt % oxygen and approx. 2500 wt ppM hydrogen at temperatures between 373 and 823/sup 0/K. Self-consistent criteria for the ductile-to-brittle transition, based upon a total absorbed energy of approx. 1.3 x 10/sup 4/ J/m/sup 2/, a dynamic fracture toughness of approx. 10 MPa.m/sup 1/2/, and a ductility index of approx. 0, were established relative to the temperature and oxygen concentration of the transformed BETA-phase material. The effect of hydrogen concentration and hydride morphology, produced by cooling Zircaloy-2 specimens through the temperature range of the BETA ..-->.. ..cap alpha..' = hydride phase transformation at approx. 0.3 and 3 K/s, on the impact properties was determined at temperatures between 373 and 673 K. On an atom fraction basis, oxygen has a greater effect than hydrogen on the impact properties of Zircaloy at temperatures between approx. 400 and 600 K. 34 figures.

  18. Impact Toughness Properties of Nickel- and Manganese-Free High Nitrogen Austenitic Stainless Steels

    NASA Astrophysics Data System (ADS)

    Mohammadzadeh, Roghayeh; Akbari, Alireza; Mohammadzadeh, Mina

    2016-12-01

    A large amount of manganese (>10 wt pct) in nickel-free high nitrogen austenitic stainless steels (Ni-free HNASSs) can induce toxicity. In order to develop Ni-free HNASSs with low or no manganese, it is necessary to investigate their mechanical properties for biomedical applications. This work aims to study the Charpy V-notch (CVN) impact toughness properties of a Ni- and Mn-free Fe-22.7Cr-2.4Mo-1.2N HNASS plate in the temperature range of 103 K to 423 K (-170 °C to 150 °C). The results show that unlike conventional AISI 316L austenitic stainless steel, the Ni- and Mn-free HNASS exhibits a sharp ductile-to-brittle transition (DBT). The intergranular brittle fracture associated with some plasticity and deformation bands is observed on the fracture surface at 298 K (25 °C). Electron backscattered diffraction (EBSD) analysis of the impact-tested sample in the longitudinal direction indicates that deformation bands are parallel to {111} slip planes. By decreasing the temperature to 273 K, 263 K, and 103 K (0 °C, -10 °C, and -70 °C), entirely intergranular brittle fracture occurs on the fracture surface. The fracture mode changes from brittle fracture to ductile as the temperature increases to 423 K (150 °C). The decrease in impact toughness is discussed on the basis of temperature sensitivity of plastic flow and planarity of deformation mechanism.

  19. Characterization of impact damage resistance of CF/PEEK and CF/toughened epoxy laminates under low and high velocity impact tests

    SciTech Connect

    Morita, Hideo; Adachi, Tadaharu; Tateishi, Yasuhiro; Matsumoto, Hiroyuki

    1995-12-31

    In order to use composite materials in aeronautical turbo engines, their resistance to impact damage must be understood. In this work the subperforation flat-wise impact resistance of three kinds of high resistance material systems were evaluated under low and high velocity impact tests. Tested systems were AS4/PEEK (APC-2/AS4, ICI-Fiberite), AS4/PEEK+IL, which consists of APC-2 prepreg and PEEK film inserted between layers as an interleave, and toughened epoxy system T800/{number_sign}3900 (Toray). To investigate the effects of stacking sequence on resistance, three lay-ups -- (0/+30/0/{minus}30)s, (0/+60/0/{minus}60)s, and (0/+45/90/{minus}45)s -- were tested. A drop weight system was used for the low velocity tests, where the velocity ranged from 1.5 to 3.1 m/s. An air gun system was used for the high velocity tests, where the velocity range was between 50 and 100 m/s. The relation between damage area (DA) and impact energy (IE) was linear, and the ratio of the DA/IE quantified the impact resistance of each specimen. The value of DA/IE for the high velocity tests was larger than the value for low velocity tests. To estimate the lay-up effect, a stacking parameter {beta}, which indicates the difference of the inplane stiffness between the adjacent laminae, was proposed. A proportional relation between the DA/IE and the {beta} was obtained. The value of (DA/IE)/{beta}, which was independent of stacking sequence, indicated the impact resistance of the tested material systems for both velocity levels. The ratio of (DA/IE)/{beta} for the high velocity to the value for the low velocity changed with material systems.

  20. What's in a Name? The Impact of Accurate Staphylococcus pseudintermedius Identification on Appropriate Antimicrobial Susceptibility Testing

    PubMed Central

    2016-01-01

    Bacteria in the Staphylococcus intermedius group, including Staphylococcus pseudintermedius, often encode mecA-mediated methicillin resistance. Reliable detection of this phenotype for proper treatment and infection control decisions requires that these coagulase-positive staphylococci are accurately identified and specifically that they are not misidentified as S. aureus. As correct species level bacterial identification becomes more commonplace in clinical laboratories, one can expect to see changes in guidance for antimicrobial susceptibility testing and interpretation. The study by Wu et al. in this issue (M. T. Wu, C.-A. D. Burnham, L. F. Westblade, J. Dien Bard, S. D. Lawhon, M. A. Wallace, T. Stanley, E. Burd, J. Hindler, R. M. Humphries, J Clin Microbiol 54:535–542, 2016, http://dx.doi.org/10.1128/JCM.02864-15) highlights the impact of robust identification of S. intermedius group organisms on the selection of appropriate antimicrobial susceptibility testing methods and interpretation. PMID:26763965