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1

On impact testing of subsize Charpy V-notch type specimens  

SciTech Connect

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.

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

1994-12-31

2

Dynamic J R curves of 308 stainless steel weld from instrumented impact test of unprecracked Charpy V-notch specimens  

Microsoft Academic Search

The present authors had earlier suggested a new (shift) procedure for obtaining the dynamic JR (J fracture resistance) curves of ductile alloys from the load-displacement traces of (unprecracked) Charpy V-notch (CVN) specimens (with CVN energy >30 J) and demonstrated the method for type 316 austenitic stainless steel (SS). This involves generating the pseudo-JR curve from CVN specimens using a key-curve

P. R. Sreenivasan; S. K. Ray; S. L. Mannan

2002-01-01

3

Predicting reference temperature from instrumented Charpy V-notch impact tests using modified Schindler procedure for computing dynamic fracture toughness  

Microsoft Academic Search

Reactor pressure vessel (RPV) steels are increasingly being characterised in terms of the reference temperature T\\u000a0 and the associated Master Curve (MC) Procedure, following the ASTM E-1921 standard. Though correlations have been proposed to predict the T\\u000a0 from Charpy transition temperature T\\u000a28J or instrumented impact test parameters like T\\u000a4kN, none can be taken as a universal

P. R. Sreenivasan; A. Moitra; S. K. Ray; S. L. Mannan

2004-01-01

4

Preparation of reconstituted Charpy V-notch impact specimens for generating pressure vessel steel fracture toughness data  

Microsoft Academic Search

The arc stud welding process has been adapted for use in producing reconstituted Charpy V-notch impact specimens. In this process, each half of a tested and fractured Charpy specimen is used as the central region of a reconstituted specimen. End tabs are joined to one half of a fractured specimen by a specially designed stud welding apparatus. SA533B-1 and SA508-2

J. S. Perrin; E. O. Fromm; W. L. Server; P. E. McConnell

1982-01-01

5

Results of charpy V-notch impact testing of structural steel specimens irradiated at {approximately}30{degrees}C to 1 x 10{sup 16} neutrons/cm{sup 2} in a commercial reactor cavity  

SciTech Connect

A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at {approximately} 30{degrees}C ({approximately} 85{degrees}F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 10{sup 16} neutrons/cm{sup 2} (> 1MeV). 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 {approximately} 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of {approximately} 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.

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

1997-04-01

6

The Evaluation of Tempered Martensite Embrittlement in 4130 Steel by Instrumented Charpy V-Notch Testing  

Microsoft Academic Search

Tempered martensite embrittlement (TME) was studied in vacuum-melted 4130 steel with either 0.002 or 0.02 wt pct P. TME was\\u000a observed as a severe decrease in Charpy V-notch impact energy, from 46 ft-lb. at 200 ?C to 35 ft-lb. at 300 ?C in the low\\u000a P alloy. The impact energy of the high P alloy was consistently lower than that

F. Zia-Ebrahimi; G. Krauss

1983-01-01

7

The evaluation of tempered martensite embrittlement in 4130 steel by instrumented charpy V-notch testing  

Microsoft Academic Search

Tempered martensite embrittlement (TME) was studied in vacuum-melted 4130 steel with either 0.002 or 0.02 wt pct P. TME was\\u000a observed as a severe decrease in Charpy V-notch impact energy, from 46 ft-lb. at 200 °C to 35 ft-lb. at 300 °C in the low\\u000a P alloy. The impact energy of the high P alloy was consistently lower than that

F. Zia-Ebrahimi; G. Krauss

1983-01-01

8

The evaluation of tempered martensite embrittlement in 4130 steel by instrumented charpy V-notch testing  

NASA Astrophysics Data System (ADS)

Tempered martensite embrittlement (TME) was studied in vacuum-melted 4130 steel with either 0.002 or 0.02 wt pct P. TME was observed as a severe decrease in Charpy V-notch impact energy, from 46 ft-lb. at 200 °C to 35 ft-lb. at 300 °C in the low P alloy. The impact energy of the high P alloy was consistently lower than that of the low P alloy in all tempered conditions. Fracture was transgranular for all specimens; therefore, segregation of P to the prior austenitic grain boundaries was not a factor in the o°Currence of TME. Analysis of load-time curves obtained by instrumented Charpy testing revealed that the embrittlement is associated with a drop in the pre-maximum-load and post-unstable-fracture energies. In specimens tempered at 400 °C the deleterious effect of phosphorus on impact energy became pronounced, a result more consistent with classical temper embrittlement rather than TME. A constant decrease in pre-maximum-load energy due to phosphorus content was observed. The pre-maximum-load energy decreases with increasing tempering temperature in the range of 200 °C to 400 °C, a result explained by the change in work hardening rate. Carbon extraction replicas of polished and etched as-quenched specimens revealed the presence of Fe2MoC and/or Fe3C carbides retained after austenitizing. Ductile crack extension close to the notch root was related to the formation of fine micro voids at the retained carbides.

Zia-Ebrahimi, F.; Krauss, G.

1983-06-01

9

Preparation of reconstituted Charpy V-notch impact specimens for generating pressure vessel steel fracture toughness data  

SciTech Connect

The arc stud welding process has been adapted for use in producing reconstituted Charpy V-notch impact specimens. In this process, each half of a tested and fractured Charpy specimen is used as the central region of a reconstituted specimen. End tabs are joined to one half of a fractured specimen by a specially designed stud welding apparatus. SA533B-1 and SA508-2 unirradiated and irradiated pressure vessel steel specimens have been produced. Both conventional and precracked reconstituted specimen data have been produced. Both types of data have been shown to be in excellent agreement with original specimen data. The arc stud welding process can therefore be used to increase the amount of data obtainable from a limited number of specimens or to obtain Charpy data when full size specimens cannot otherwise be obtained.

Perrin, J.S. (Fracture Control Corp., Goleta, CA); Fromm, E.O.; Server, W.L.; McConnell, P.E.

1982-01-01

10

Computer Model for Ductile Fracture: Applications to the Charpy V-Notch Test. Phase One Report.  

National Technical Information Service (NTIS)

A computer model for predicting ductile-fracture initiation and propagation in nuclear reactor pressure vessel steel is described. The model predicts fracture toughness from Charpy and tension tests using standard surveillance specimens. The fracture mode...

D. M. Norris J. E. Reaugh B. Moran D. F. Quinones

1979-01-01

11

Study of Tempered Martensite Embrittlement Using Standard and Subsize V-Notch Charpy Specimens.  

National Technical Information Service (NTIS)

Various sizes of V-notch and fatigue precracked Charpy specimens, tested in impact and slow bend, were used to study tempered martensite embrittlement in a 4340 steel. When plotted as a function of tempering temperature, the results showed that the magnit...

T. M. F. Ronald

1969-01-01

12

Effects of Notch Misalignment and Tip Radius on Displacement Field in V-Notch Rail Shear Test as Determined by Photogrammetry  

NASA Technical Reports Server (NTRS)

Evolution of the 3D strain field during ASTM-D-7078 v-notch rail shear tests on 8-ply quasi-isotropic carbon fiber/epoxy laminates was determined by optical photogrammetry using an ARAMIS system. Specimens having non-optimal geometry and minor discrepancies in dimensional tolerances were shown to display non-symmetry and/or stress concentration in the vicinity of the notch relative to a specimen meeting the requirements of the standard, but resulting shear strength and modulus values remained within acceptable bounds of standard deviation. Based on these results, and reported difficulty machining specimens to the required tolerances using available methods, it is suggested that a parametric study combining analytical methods and experiment may provide rationale to increase the tolerances on some specimen dimensions, reducing machining costs, increasing the proportion of acceptable results, and enabling a wider adoption of the test method.

Hill, Charles S.; Oliveras, Ovidio M.

2011-01-01

13

A fracture criterion for blunted V-notched samples  

Microsoft Academic Search

This paper shows how the cohesive zone model can help in predicting fracture loads of brittle components with blunted V-notches. Linear Elastic Fracture Mechanics cannot be applied in such cases because there are no singularities; there is no crack, and neither is the notch sharp. Numerical predictions based on the cohesive zone model were checked succesfully against experimental measurements for

F. J. Gómez; M. Elices

2004-01-01

14

Drop-Weight Tests of Experimental HY-130/150 Steels.  

National Technical Information Service (NTIS)

One of the most important requirements of HY130/150 steels and weldments is high fracture toughness. For laboratory screening of experimental steels, fracture toughness can be most conveniently determined from Charpy V-notch impact tests. However, fractur...

S. T. Rolfe

1964-01-01

15

Effect of neutron irradiation on the dynamic fracture toughness behavior of the 12% Cr steel MANET-I investigated using subsize V-notch specimens  

NASA Astrophysics Data System (ADS)

The effect of neutron irradiation on the dynamic fracture toughness behaviour of the 12% Cr steel MANET-I was investigated using DIN 50115-KLST, subsize, V-notch impact bend specimens (3 × 4 × 27 mm3). The microstructure of the steel was varied by employing different quenching and austenizing conditions. The specimens were irradiated in the HFR Petten at 300, 400, and 475°C to displacement damage levels as high as 5 dpaNRT. Experimental results are reported from an ongoing program aimed at determining the influence of irradiation-induced microstructural changes on the impact properties of MANET-I: the ductile-to-brittle transition temperature (DBTT), the relative fracture toughness, and the dynamic plane strain fracture toughness. Following irradiation a large increase in the DBTT and a remarkable decrease in the upper-shelf energy (USE) were observed. The changes in the properties depend strongly on the irradiation temperature. The DBTT and USE of the irradiated specimens also depend clearly on the initial microstructure of the material. The increase in DBTT and the decrease in USE are in general greater at 300 than at 400 and 475°C. Under proper conditions the instrumented impact test can be used to determine the dynamic plane strain fracture toughness K1d and the J-integral of unirradiated and irradiated materials.

Wassilew, Christo; Ehrlich, Karl

1992-09-01

16

Three-dimensional vibrations of cylindrical elastic solids with V-notches and sharp radial cracks  

NASA Astrophysics Data System (ADS)

This paper provides free vibration data for cylindrical elastic solids, specifically thick circular plates and cylinders with V-notches and sharp radial cracks, for which no extensive previously published database is known to exist. Bending moment and shear force singularities are known to exist at the sharp reentrant corner of a thick V-notched plate under transverse vibratory motion, and three-dimensional (3-D) normal and transverse shear stresses are known to exist at the sharp reentrant terminus edge of a V-notched cylindrical elastic solid under 3-D free vibration. A theoretical analysis is done in this work utilizing a variational Ritz procedure including these essential singularity effects. The procedure incorporates a complete set of admissible algebraic-trigonometric polynomials in conjunction with an admissible set of " edge functions" that explicitly model the 3-D stress singularities which exist along a reentrant terminus edge (i.e., ?>180°) of the V-notch. The first set of polynomials guarantees convergence to exact frequencies, as sufficient terms are retained. The second set of edge functions—in addition to representing the corner stress singularities—substantially accelerates the convergence of frequency solutions. This is demonstrated through extensive convergence studies that have been carried out by the investigators. Numerical analysis has been carried out and the results have been given for cylindrical elastic solids with various V-notch angles and depths. The relative depth of the V-notch is defined as (1- c/ a), and the notch angle is defined as (360°- ?). For a very small notch angle (1° or less), the notch may be regarded as a "sharp radial crack." Accurate (four significant figure) frequencies are presented for a wide spectrum of notch angles (360°- ?), depths (1- c/ a), and thickness ratios ( a/ h for plates and h/ a for cylinders). An extended database of frequencies for completely free thick sectorial, semi-circular, and segmented plates and cylinders are also reported herein as interesting special cases. A generalization of the elasticity-based Ritz analysis and findings applicable here is an arbitrarily shaped V-notched cylindrical solid, being a surface traced out by a family of generatrix, which pass through the circumference of an arbitrarily shaped V-notched directrix curve, r( ?), several of which are described for future investigations and close extensions of this work.

McGee, O. G.; Kim, J. W.

2010-02-01

17

46 CFR 54.05-5 - Toughness test specimens.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Toughness test specimens. 54.05-5 Section 54.05-5...MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-5 Toughness test specimens. (a) Charpy V-notch impact...

2013-10-01

18

Charpy impact energy, fracture toughness and ductile–brittle transition temperature of dual-phase 590 Steel  

Microsoft Academic Search

Advanced high strength steels (AHSS) have been introduced and gradually adopted in vehicle structures as lightweight materials in the past years. Engineering performance of AHSS in many areas have shown that they are superior to the conventional steels. In this paper, we present the results from Charpy V-Notch impact tests on dual phase 590 (DP590) steel, which belongs to the

Y. J. Chao; J WARDJR; R. G. Sands

2007-01-01

19

Dynamic JR curves and tension-impact properties of AISI 308 stainless steel weld  

Microsoft Academic Search

In this paper, instrumented tension-impact (dynamic tensile) and instrumented Charpy impact test results for AISI 308 stainless steel welds at room temperature are reported. A few Charpy specimens precracked to a\\/W (crack length to width ratio) ratios of 0.42 to 0.59 were also tested. Dynamic yield strength obtained from tension-impact test agrees well with that from Charpy V-notch specimens. The

P. R. Sreenivasan; S. L. Mannan

2000-01-01

20

Impact Sensitivity Tests.  

National Technical Information Service (NTIS)

Various test methods for mechanical impact sensitivity are reviewed with special attention to such topics as drop hammer tests for desensitized explosives, judgement of test results, composition of decomposition gases from drop hammer tests, correlation o...

T. Yoshida M. Tamura M. Yoshida

1978-01-01

21

Characterising the process zone in complete fretting contacts using plain fatigue sharp V-notch specimens  

NASA Astrophysics Data System (ADS)

The object of this analysis is to demonstrate that it is possible to replicate the conditions prevalent in the process zone of a 'complete' locally slipping contact with an equivalent V-notch plain fatigue specimen. The methodology is as follows: using an asymptotic approach, we can determine the eigenvalues and hence spatial distribution of stresses for both the fretting and notch configurations, in the latter case, based on the Williams' solution. The first step, is to match these eigenvalues, and subsequently, to compare the resulting distribution of stresses. It will be shown that, although there is a comparatively large range of combinations of pad geometry and coefficients of friction where this is feasible, it is only for a very limited range that the resulting stress distributions coincide. This therefore, presents a means of isolating the effects of the differential motion and hence, slip displacement, characteristic of fretting contacts. The experimental implications of these results together with their limitations will be discussed.

Mugadu, A.; Hills, D. A.

2002-07-01

22

Impact Tests for Woods  

NASA Technical Reports Server (NTRS)

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.

1922-01-01

23

Effects of carburization and hydrogenation on the impact toughness of AISI 4118 steel  

Microsoft Academic Search

The effects of hydrogen charging and carburization on the impact toughness of an AISI 4118 steel were studied. The carburization of impact specimens was conducted using a conventional pack carburizing method and the hydrogen charging was conducted in 1 N H2SO4 solution containing 1 g I?1 of thiourea at 30°C. Charpy V-notch impact tests were carried out on specimens with

Chih Fu Yang; Liu Ho Chiu; Jiann Kuo Wu

1995-01-01

24

Charpy V-notch properties and microstructures of narrow gap ferritic welds of a quenched and tempered steel plate  

SciTech Connect

Multipass welds of quenched and tempered 50-mm-thick steel plate have been deposited by a single wire narrow gap process using both gas metal arc welding (GMAW) and submerged arc welding (SAW). Of the five welds, two reported much lower Charpy V-notch (CVN) values when tested at {minus} 20 C. The CVN toughness did not correlate with either the welding process or whether the power source was pulsed or nonpulsed. The only difference in the ferritic microstructure between the two welds of low Charpy values and the three of high values was the percentage of acicular ferrite. There was no effect of the percentage of as-deposited reheated zones intersected by the Charpy notch or the microhardness of the intercellular-dendritic regions. In all welds, austenite was the microconstituent between the ferrite laths. The percentage of acicular ferrite correlated with the presence of MnO, TiO{sub 2}, {gamma} Al{sub 2}O{sub 3}, or MnO. Al{sub 2}O{sub 3} as the predominant crystalline compound in the oxide inclusions. In turn, the crystalline compound depended on the aluminum-to-titanium ratio in both the weld deposits and the oxide inclusions. In addition to the presence of less acicular ferrite, the two welds that showed lower Charpy values also reported more oxide inclusions greater than 1 {micro}m in diameter. The combination of more oxide inclusions greater than 1 {micro}m and less acicular ferrite is considered to be the explanation for the lower Charpy values.

Powell, G.L.F.; Herfurth, G. [Commonwealth Scientific and Industrial Research Organization, Woodville (Australia)

1998-11-01

25

Vortical structures in a laminar V-notched indeterminate-origin jet  

NASA Astrophysics Data System (ADS)

A flow visualization investigation using dye-injection and laser-induced fluorescence techniques has been carried out to understand the vortex dynamics resulting from a V-notched indeterminate-origin jet with two peaks and two troughs. The laminar jet (Re=2000) was studied under forcing and nonforcing conditions to investigate the resultant dynamics of coherent large- and small-scale flow structures. Present experimental observations indicated that the effects of the nozzle peaks and troughs differ from those reported previously. Instead of the peaks producing streamwise vortex pairs which spread outwards into the ambient fluid and the troughs generating similar vortex pairs but entraining ambient fluid into the jet flows as indicated by earlier studies, the present experimental observations showed that both peaks and troughs produce outward-spreading streamwise vortex pairs. Laser cross sections further showed that the subsequent formation of azimuthal ring vortices causes these streamwise vortex pairs to be entrained. This entrainment causes the streamwise vortex pairs to ``roll-up'' together with the ring vortices, leading to intense flow interactions between them. Interestingly, in a comparison with the experimental study reported by Longmire et al. [``Control of jet structure by crown-shaped nozzles,'' AIAA J. 30, 505 (1992)] using higher Reynolds number air jet (Re=19 000), it was found that forced jet flows with four peaks and four troughs yielded practically the same flow observations as the present nozzles with two peaks and two troughs. An updated flow model based on instantaneous and time-averaged evidence is presented to explain how the interaction of the vortex structures will give rise to the present new observations.

New, T. H.; Lim, K. M. K.; Tsai, H. M.

2005-05-01

26

Small punch test evaluation of intergranular embrittlement of an alloy steel  

Microsoft Academic Search

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

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

1983-01-01

27

Southern Impact Testing Alliance (SITA)  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

28

CANFLEX fuel bundle impact test.  

National Technical Information Service (NTIS)

This document outlines the test results for the impact test of the CANFLEX fuel bundle. Impact test is performed to determine and verify the amount of general bundle shape distortion and defect of the pressure tube that may occur during refuelling. The te...

S. K. Chang C. Chung J. Park S. Hong B. Kim

1997-01-01

29

Controlled Tank Car Impact Tests.  

National Technical Information Service (NTIS)

A series of controlled tank car impact tests were performed by the Association of American Railroads as part of a Federal Railroad Administration Task Order entitled Hazardous Materials Transportation Safety Research Test Program. The objective of these t...

R. K. Larson B. R. Rajkumar

1992-01-01

30

Solution for the stress and displacement fields in the vicinity of a V-notch of negative wedge angle in plane problems of elasticity  

Microsoft Academic Search

The method is presented of modeling displacement, strain and stress fields in the two-dimensional problems of elasticity considering the presence of V-shaped notches with any positive or negative angle. The analytical expressions for stress and strain states at the tip of a V-notch were obtained for two cases of deformation: opening (mode I) and sliding (mode II). This was achieved

Andrzej Seweryn; Janislaw Zwolinski

1993-01-01

31

AXAF hypervelocity impact test results  

NASA Technical Reports Server (NTRS)

Composite and honeycomb panels are commonly used for spacecraft structural components. The impact test results and analysis of six different composite and honeycomb combinations for use on the advanced X-ray astrophysics facility (AXAF) are reported. The AXAF consists of an X-ray telescope and the associated detecting devices attached to an octagonal spacecraft with an internal propulsion system. The spacecraft's structural panels and optical bench are made of two different graphite fiber reinforced polyimides or composite panels bonded to either side of an aluminum honeycomb. The instrument is required to have at least a 0.92 probability of no failure of any of the critical elements due to meteoroids and debris. In relation to the no-failure probability determination in its low earth orbit environment, hypervelocity impact testing was performed to determine the ballistic limit range and the extent of damage due to impact. The test results for a power and signal cable bundle located behind a panel are presented. Tests planned for a multilayer insulation (MLI) blanket and four types of cable bundles are discussed.

Frost, Cynthia L.; Rodriguez, Pedro I.

1997-01-01

32

Dynamic impact testing with servohydraulic testing machines  

NASA Astrophysics Data System (ADS)

The design concept of “Crashworthiness” requires the information on material behaviour under dynamic impact loading in order to describe and predict the crash behaviour of structures. Especially the transport related industries, like car, railway or aircraft industry, pursue the concept of lightweight design for a while now. The materials' maximum constraint during loading is pushed to permanently increasing figures. This means in terms of crashworthiness that the process of energy absorption in structures and the mechanical behaviour of materials must well understood and can be described appropriately by material models. In close cooperation with experts from various industries and research institutes Instron has developed throughout the past years a new family of servohydraulic testing machines specifically designed to cope with the dynamics of high rate testing. Main development steps are reflected versus their experimental necessities.

Bardenheier, R.; Rogers, G.

2006-08-01

33

Defense Waste Processing Facility Canister Impact Testing.  

National Technical Information Service (NTIS)

This report summarizes impact testing of seven Defense Waste Processing Facility (DWPF) high level waste canisters during FY 1988. Impact testing was conducted to demonstrate compliance of DWPF canisters with the drop test specification of the Waste Accep...

K. M. Olson J. M. Alzheimer

1989-01-01

34

Effect of postweld heat treatment on weld metal impact toughness of a semi-austenitic PH stainless steel  

Microsoft Academic Search

Semi-austenitic precipitation hardened PH stainless steel plates, PH 15-7 Mo (Cu), 6.14 mm thick were autogenously welded using the electron beam welding (EBW) and plasma arc welding (PAW) processes. Impact toughness studies using Charpy V-notch samples (V-notch at the center of the weld metal) showed that EB welds had higher impact toughness than PA welds in various identical postweld heat

N. Sivaramakrishnan; K. S. Raja; K. Prasad Rao

1994-01-01

35

High Pressure Quick Disconnect Particle Impact Tests.  

National Technical Information Service (NTIS)

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...

J. M. Stoltzfus K. R. Rosales

2009-01-01

36

Development of ball impact test system  

Microsoft Academic Search

We introduce in this paper background and development of the high-speed ball shear test systems, in particular a specific ball impact test system. Measured impact force profiles and corresponding structural dynamics calibrations are provided for the understanding of characteristics of this particular package-level test methodology as well as transient structural responses of solder joints subjected to impact loads. A design

Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

37

Impact toughness of reinforcing steels produced by (i) the Tempcore process and (ii) microalloying with vanadium  

Microsoft Academic Search

A “direct measurement” of the impact toughness of both Tempcore and microalloyed with vanadium reinforcing steel bars, of the same strength class (500MPa nominal yield stress), is undertaken. The term “direct measurement” means that V-notched specimens with the original round section of the bars (and not with the standard rectangular one) are used, mentioned here as direct V-notched (DVN) specimens.

John Nikolaou; George D. Papadimitriou

2005-01-01

38

Auburn Micrometeoroid Impact Test Data Analysis  

NASA Technical Reports Server (NTRS)

This presentation provides an overview and summary of micrometeoroid impact testing performed by Auburn University and an analysis of the test results. The testing at Auburn utilized existing facilities at Auburn to generate hypervelocity impacts into multiple layers of thin Kapton films representative of the NASA concept for the NGST sunshield. The test data consists of impactor particle mass and velocity, and for each film layer, the number and size of holes generated by the initial impact and resulting impact debris. The analysis consists of combining the test data with existing impact effects models and the micrometeoroid environment at the L2 operating location of NGST to predict sunshield degradation.

Perrygo, Charles; Best, Steve; Stahl, H. Philip (Technical Monitor)

2001-01-01

39

Plane elasto-plastic analysis of v-notched plate under bending by boundary integral equation method. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

A method of solution is presented, which, when applied to the elasto-plastic analysis of plates having a v-notch on one edge and subjected to pure bending, will produce stress and strain fields in much greater detail than presently available. Application of the boundary integral equation method results in two coupled Fredholm-type integral equations, subject to prescribed boundary conditions. These equations are replaced by a system of simultaneous algebraic equations and solved by a successive approximation method employing Prandtl-Reuss incremental plasticity relations. The method is first applied to number of elasto-static problems and the results compared with available solutions. Good agreement is obtained in all cases. The elasto-plastic analysis provides detailed stress and strain distributions for several cases of plates with various notch angles and notch depths. A strain hardening material is assumed and both plane strain and plane stress conditions are considered.

Rzasnicki, W.

1973-01-01

40

Charpy impact test results on five materials and NIST verification specimens using instrumented 2-mm and 8-mm strikers  

SciTech Connect

The Heavy-Section Steel Irradiation Program at Oak Ridge National Laboratory is involved in two cooperative projects, with international participants, both of which involve Charpy V-notch impact tests with instrumented strikers of 2mm and 8mm radii. Two heats of A 533 grade B class I pressure vessel steel and a low upper-shelf (LUS) submerged-arc (SA) weld were tested on the same Charpy machine, while one heat of a Russian Cr-Mo-V forging steel and a high upper-shelf (HUS) SA weld were tested on two different machines. The number of replicate tests at any one temperature ranged from 2 to 46 specimens. Prior to testing with each striker, verification specimens at the low, high, and super high energy levels from the National Institute of Standards and Technology (NIST) were tested. In the two series of verification tests, the tests with the 2mm striker met the requirements at the low and high energy levels but not at the super high energy. For one plate, the 2mm striker showed somewhat higher average absorbed energies than those for the 8-mm striker at all three test temperatures. For the second plate and the LUS weld, however, the 2mm striker showed somewhat lower energies at both test temperatures. For the Russian forging steel and the HUS weld, tests were conducted over a range of temperatures with tests at one laboratory using the 8mm striker and tests at a second laboratory using the 2mm striker. Lateral expansion was measured for all specimens and the results are compared with the absorbed energy results. The overall results showed generally good agreement (within one standard deviation) in energy measurements by the two strikers. Load-time traces from the instrumented strikers were also compared and used to estimate shear fracture percentage. Four different formulas from the European Structural Integrity Society draft standard for instrumented Charpy test are compared and a new formula is proposed for estimation of percent shear from the force-time trace.

Nanstad, R.K.; Sokolov, M.A.

1995-04-01

41

Solid rocket booster water impact test  

NASA Technical Reports Server (NTRS)

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.

Bugg, F.

1982-01-01

42

Dynamic Tests on Metallic Impact Limiters.  

National Technical Information Service (NTIS)

Three different types of metallic impact limiters were tested; plain fins, laterally stiffened fins and tubes whose axes were aligned with the direction of impact. All specimens were made of 304 stainless steel and were annealed before testing. A heavy st...

M. J. Sagartz

1978-01-01

43

Impact Testing and Dynamic Behavior of Materials  

Microsoft Academic Search

\\u000a This paper gives an overview of different testing facilities and the mechanical material behavior including monoaxial and\\u000a multi axial testing under high rate loading. Special emphasis is laid on difficult loading conditions and loading states such\\u000a high temperature and high strain loading (?>1200°C, ?>1) and multiaxial impact tests. The impact behavior of selected materials\\u000a is shown and compared under different

Lothar W. Meyer; Norman Herzig; Frank Pursche; Shawky Abdel-Malek

44

Reproducibility of liquid oxygen impact test results  

NASA Technical Reports Server (NTRS)

Results for 12,000 impacts on a wide range of materials were studied to determine the reproducibility of the liquid oxygen impact test method. Standard deviations representing the overall variability of results were in close agreement with the expected values for a binomial process. This indicates that the major source of variability is due to the go - no go nature of the test method and that variations due to sampling and testing operations were not significant.

Gayle, J. B.

1975-01-01

45

Kolsky Bar Impact Test Facility  

SciTech Connect

Testing for the Kolsky Bar is conducted at Los Alamos National Laboratory, Los Alamos, New Mexico. The Kolsky bar is operated by the Dynamic testing team of NMT-11, (Nuclear Material Technology Division) to enable measurements of stress-strain characteristics for the MST-8 (Material Science and Technology) personnel. The Kolsky Bar is located at the Plutonium Facility at TA-55 (Tech Area).

Contreras, P.; Montoya, J.

1998-12-31

46

Permeability After Impact Testing of Composite Laminates  

NASA Technical Reports Server (NTRS)

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.

Nettles, Alan T.

2003-01-01

47

Permeability After Impact Testing of Composite Laminates  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

48

Water impact shock test system  

NASA Technical Reports Server (NTRS)

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.

1977-01-01

49

Standardisation of Impact Testing of Protective Helmets.  

National Technical Information Service (NTIS)

The study classifies currently used test procedures, and proposes a compromise approach which could form the basis for agreement within the NATO membership for helments for aircrew designed to widely differing standards. In addition to impact protection, ...

D. H. Glaister

1975-01-01

50

Impact testing of textile composite materials  

NASA Technical Reports Server (NTRS)

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.

Portanova, Marc

1995-01-01

51

Impact tests on fibrous composite sandwich structures  

NASA Technical Reports Server (NTRS)

The effect of low velocity impact on the strength of laminates fabricated from graphite/epoxy and Kevlar 49/epoxy composite materials was studied. The test laminates were loaded statically either in uniaxial tension or compression when impact occurred to evaluate the effect of loading on the initiation of damage and/or failure. Typical aircraft service conditions such as runway debris encountered during landing were simulated by impacting 1.27-cm-diameter projectiles normal to the plane of the test laminates at velocities between 5.2 and 48.8 m/s.

Rhodes, M. D.

1978-01-01

52

Tests of the Giant Impact Hypothesis  

NASA Technical Reports Server (NTRS)

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.

Jones, J. H.

1998-01-01

53

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

NASA Astrophysics Data System (ADS)

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.

Bouchard, Real

54

Heavy Truck Pilot Crash Test: Frontal Impact.  

National Technical Information Service (NTIS)

A frontal impact test of a tractor-trailer into a crushable barrier at a nominal initial speed of 30 mph was performed. The test vehicle, which was operated at a total combination weight of 34,690 lbs., carried two 50th percentile Part 572 anthropomorphic...

R. S. Rice N. E. Shoemaker

1981-01-01

55

Fod Impact Testing of Composite Fan Blades.  

National Technical Information Service (NTIS)

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 additio...

R. H. Johns

1974-01-01

56

Impact testing on composite fan blades  

NASA Technical Reports Server (NTRS)

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.

Johns, R. H.

1974-01-01

57

FOD impact testing of composite fan blades  

NASA Technical Reports Server (NTRS)

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.

Johns, R. H.

1974-01-01

58

FOD impact testing of composite fan blades  

NASA Technical Reports Server (NTRS)

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.

Johns, R. H.

1974-01-01

59

Mechanical Impact Testing: A Statistical Measurement  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

60

Effect of postweld heat treatment on weld metal impact toughness of a semi-austenitic PH stainless steel  

SciTech Connect

Semi-austenitic precipitation hardened PH stainless steel plates, PH 15-7 Mo (Cu), 6.14 mm thick were autogenously welded using the electron beam welding (EBW) and plasma arc welding (PAW) processes. Impact toughness studies using Charpy V-notch samples (V-notch at the center of the weld metal) showed that EB welds had higher impact toughness than PA welds in various identical postweld heat treated (PWHT) conditions. Based on hardness and impact toughness values, the optimal postweld heat treated conditions are recommended. The effect of retained austenite, carbides and delta ferrite on impact toughness of the welds are discussed.

Sivaramakrishnan, N.; Raja, K.S.; Prasad Rao, K. (Indian Inst. of Tech., Madras (India). Dept. of Metallurgical Engineering)

1994-08-01

61

Defense Waste Processing Facility canister impact testing  

SciTech Connect

This report summarizes impact testing of seven Defense Waste Processing Facility (DWPF) high level waste canisters during FY 1988. Impact testing was conducted to demonstrate compliance of DWPF canisters with the drop test specification of the Waste Acceptance Preliminary Specification. The prototypical stainless steel canisters were filled with simulated waste to about 85% capacity at Savannah River Laboratory (SRL). They were received from SRL in April 1988. Each canister was approximately 300 cm (9 ft 10 in.) long, and 61 cm (2 ft) in diameter, and weighed about 2150 kg (4740 lb). Each canister was dropped twice from a height of 7 m (23 ft). The first drop was a vertical bottom impact where the bottom of the canister was oriented parallel to the impact pad. The second was a center-of-gravity-over-the-corner top impact. Procedures used to examine the canisters were the application and analysis of strain circles, helium leak testing, dye penetrant examination, and canister dimensional measurements. 39 refs., 39 figs., 11 tabs.

Olson, K.M.; Alzheimer, J.M.

1989-09-01

62

Design of an impact abrasion testing machine  

NASA Astrophysics Data System (ADS)

By using a cam-flat follower-impact shaft with a crank-flat rotating anvil system, the machine to be described can create various impact abrasion conditions to simulate a large range of industrial situations encountered in this field. The main features of the machine are the long working life of the flat rotating anvil, which works in the same way as that of the disk in a pin-on-disk wear tester, and the accurate control of both the impact energy delivered to the specimen and the total sliding distance of the specimen on the anvil. Statistical analysis of test results on the machine with EN24 steel and cast high manganese steel shows that the uncertainty of the population mean is within +/- 4.7% of the sample mean under a 95% confidence level of student distribution, which indicates a very good accuracy of test.

Zhang, D.; Beeley, P. R.; Baker, A. J.

1994-04-01

63

REAR IMPACT TEST METHODOLOGIES: QUASISTATIC AND DYNAMIC  

Microsoft Academic Search

The performance of a vehicle's seat back in rear impact accidents can significantly affect occupant kinematics and resulting injury potential. The only current United States (U.S.) government regulation addressing seat back strength is outlined in Federal Motor Vehicle Safety Standard (FMVSS) 207, Seating Systems (1). The test method outlined in this regulation is only partially predictive of seat performance in

Brian R. Herbst; Steven E. Meyer; Arin A. Oliver; Stephen M. Forrest

64

Impact Landing Dynamics Facility Crash Test  

NASA Technical Reports Server (NTRS)

By 1972 the Lunar Landing Research Facility was no longer in use for its original purpose. The 400-foot high structure was swiftly modified to allow engineers to study the dynamics of aircraft crashes. 'The Impact Dynamics Research Facility is used to conduct crash testing of full-scale aircraft under controlled conditions. The aircraft are swung by cables from an A-frame structure that is approximately 400 ft. long and 230 foot high. The impact runway can be modified to simulate other grand crash environments, such as packed dirt, to meet a specific test requirement.' 'In 1972, NASA and the FAA embarked on a cooperative effort to develop technology for improved crashworthiness and passenger survivability in general aviation aircraft with little or no increase in weight and acceptable cost. Since then, NASA has 'crashed' dozens of GA aircraft by using the lunar excursion module (LEM) facility originally built for the Apollo program.' This photograph shows Crash Test No. 7.

1975-01-01

65

Full-scale aircraft impact test for evaluation of impact forces: Part 1, Test plan, test method, and test results  

SciTech Connect

One of the factors considered in the design of critical concrete structures is the estimation of the global elasto-plastic structural response caused by the accidental impact of an aircraft. To estimate the response of the structure, the impact force (the force versus time relationship) must be known. Previous analytical studies have derived the forcing function using the impact velocity of the aircraft and the calculated mass and strength distribution of the aircraft. This paper describes a test conducted on April 19, 1988, at an existing rocket sled facility at Sandia National Laboratories in Albuquerque, New Mexico, USA, in which an actual F-4 Phantom aircraft was impacted at a nominal velocity of 215 m/s into an essentially rigid block of concrete. This was accomplished by supporting the F-4 on four struts that were attached to the sled track by carriage shoes to direct the path of the aircraft. Propulsion was accomplished by two stages of rockets. The concrete target was 'floated' on a set of air bearings. Data acquisition consisted of measurements of the acceleration of the fuselage and engines of the F-4, and measurements of the displacement, velocity and acceleration of the concrete target. High-speed photography recorded the impact process and also permitted the determination of the impact velocity. This paper describes the test plan, method and results, while a companion paper discusses the analyses of the results. 6 refs., 11 figs.

von Riesemann, W.A.; Parrish, R.L.; Bickel, D.C.; Heffelfinger, S.R.; Muto, K.; Sugano, T.; Tsubota, H.; Koshika, N.; Suzuki, M.; Ohrui, S.

1989-03-01

66

Static Tests of One-third Scale Impact Limiters.  

National Technical Information Service (NTIS)

The National Institute of Standards and Technology carried out four tests of one-third scale impact limiters for Transnuclear, Inc. The impact limiters were tested under static load in a 12-million pound capacity universal testing machine. Energy absorbed...

L. T. Phan H. S. Lew

1989-01-01

67

Impact Landing Dynamics Facility Crash Test  

NASA Technical Reports Server (NTRS)

By 1972 the Lunar Landing Research Facility was no longer in use for its original purpose. The 400-foot high structure was swiftly modified to allow engineers to study the dynamics of aircraft crashes. The Impact Dynamics Research Facility is used to conduct crash testing of full- scale aircraft under controlled conditions. The aircraft are swung by cables from an A-frame structure that is approximately 400 ft. long and 230 foot high. The impact runway can be modified to simulate other grand crash environments, such as packed dirt, to meet a specific test requirement. In 1972, NASA and the FAA embarked on a cooperative effort to develop technology for improved crashworthiness and passenger survivability in general aviation aircraft with little or no increase in weight and cceptable cost. Since then, NASA has 'crashed' dozens of GA aircraft by using the lunar excursion module (LEM) facility originally built for the Apollo program.

1975-01-01

68

Impeller wear impact-abrasive wear test  

Microsoft Academic Search

In order to more accurately simulate wear behavior that occurs in the field (i.e., impact coupled with abrasion), an impeller-in-drum wear test has been developed. The apparatus is similar to the one first developed by Bond; however, in the apparatus used at the Albany Research Center, three paddles instead of just one are situated in the drum which can be

R. D Wilson; J. A Hawk

1999-01-01

69

Apollo command module land impact tests  

NASA Technical Reports Server (NTRS)

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.

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

1972-01-01

70

On Low-Velocity Impact Testing of Composite Materials  

Microsoft Academic Search

The importance of understanding the response of structural composites to impact cannot be overstated. This understanding includes both the impact phenomena themselves and the influence of materials properties on the impact response. This paper presents the need for instrumented testing to optimize our understanding of the impact event, especially the response of the impacted material. The conclusion is drawn that

Peter O. Sjoblom; J. Timothy Hartness; Tobey M. Cordell

1988-01-01

71

The GISS sounding temperature impact test  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

72

Detailed Modeling of the Train-to-Train Impact Test: Rail Passenger Equipment Impact Tests.  

National Technical Information Service (NTIS)

This report describes the results of a finite element-based analysis of the train-to-train impact test conducted at the Federal Railroad Administrations Transportation Technology Center in Pueblo, CO, on January 31, 2002. The ABAQUS/Explicit dynamic finit...

R. Stringfellow P. Llana

2007-01-01

73

Constitutive modeling using the Taylor impact test  

SciTech Connect

The Taylor test can be conveniently divided into three fairly distinct stages: (1) initial transient behavior after impact characterized by nonlinear plastic wave propagation. (2) quasi-steady propagation of the plastic wave front. The duration of this stage is a function of specimen caliber and material. (3) terminal transient behavior, during which most of the deceleration of the undeformed section takes place. After the initial transient is complete, which varies with the strain at which the plastic wave front propagates, the motion is well behaved, in the sense that a one-dimensional analysis can be effectively applied. This paper contains such an analysis. Results are supported by an example from which the state of stress for an OFHC copper specimen is deduced.

Jones, S.E. [Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Mechanical Engineering; Maudlin, P.J. [Los Alamos National Lab., NM (United States); Foster, J.C. Jr. [Air Force Armament Lab., Eglin AFB, FL (United States)

1995-09-01

74

Measurement Techniques for Hypervelocity Impact Test Fragments  

NASA Technical Reports Server (NTRS)

The ability to classify the size and shape of individual orbital debris fragments provides a better understanding of the orbital debris environment as a whole. The characterization of breakup fragmentation debris has gradually evolved from a simplistic, spherical assumption towards that of describing debris in terms of size, material, and shape parameters. One of the goals of the NASA Orbital Debris Program Office is to develop high-accuracy techniques to measure these parameters and apply them to orbital debris observations. Measurement of the physical characteristics of debris resulting from groundbased, hypervelocity impact testing provides insight into the shapes and sizes of debris produced from potential impacts in orbit. Current techniques for measuring these ground-test fragments require determination of dimensions based upon visual judgment. This leads to reduced accuracy and provides little or no repeatability for the measurements. With the common goal of mitigating these error sources, allaying any misunderstandings, and moving forward in fragment shape determination, the NASA Orbital Debris Program Office recently began using a computerized measurement system. The goal of using these new techniques is to improve knowledge of the relation between commonly used dimensions and overall shape. The immediate objective is to scan a single fragment, measure its size and shape properties, and import the fragment into a program that renders a 3D model that adequately demonstrates how the object could appear in orbit. This information would then be used to aid optical methods in orbital debris shape determination. This paper provides a description of the measurement techniques used in this initiative and shows results of this work. The tradeoffs of the computerized methods are discussed, as well as the means of repeatability in the measurements of these fragments. This paper serves as a general description of methods for the measurement and shape analysis of orbital debris.

Hill, Nicole E.

2008-01-01

75

Development of an oxygen impact-testing method  

NASA Technical Reports Server (NTRS)

The development of a gaseous oxygen impact test method to aid in the selection of materials for high pressure oxygen systems is discussed. The objectives of the tests and the test equipment used are described. It is concluded that the impact test procedures are adequate for present purposes, but cannot be depended upon for establishing future standards.

Jamison, H. H.

1971-01-01

76

An Empirical Investigation of Impact Moderation in Test Construction.  

ERIC Educational Resources Information Center

Constructed four different kinds of test sections using three methods of test assembly that incorporate the goals of simultaneous moderation of the impact of gender, African American status, and Hispanic-American status, resulting in 10 test forms completed by at least 7,000 test takers per form. Discusses the effects of moderating impact in this…

Stocking, Martha L.; Lawrence, Ida; Feigenbaum, Miriam; Jirele, Thomas; Lewis, Charles; Van Essen, Thomas

2002-01-01

77

Research-tested Intervention Programs: Intervention Impact  

Cancer.gov

Intervention Impact Score Calculation Intervention impact is calculated based on population reach and intervention effect size that are rated separately and combined into a single score based on the following: Reach Score Effect Size Score Combined Intervention

78

Pipe-to-Pipe Impact Tests.  

National Technical Information Service (NTIS)

The objective of the program is to generate experimental data to evaluate the Nuclear Regulatory Commission's requirements for predicting impact damage. These state that upon impact between two pipes it shall be assumed that the moving pipe will: rupture ...

M. C. C. Bampton J. M. Alzheimer F. A. Simonen

1982-01-01

79

Impact Tests on Fibre Metal Laminates under a Tensile Load.  

National Technical Information Service (NTIS)

The well-known sensitivity of conventional composites to incidental damage such as impact has slowed their widespread application to thin, damage tolerance-critical primary structures such as fuselage pressure cabin skins. Therefore, impact tests were per...

A. Vlot

1993-01-01

80

Tyre Impact Tests on Airport Landing Lights.  

National Technical Information Service (NTIS)

Measurements were made of 'impact factors' for a 35 x 10 x 17 in aircraft wheel rolling over a selection of airfield landing lights; the 'impact factor' being the maximum dynamic load due to the impact with the landing light divided by the normal load jus...

T. Williams

1968-01-01

81

Instrumented impact testing at high velocities  

Microsoft Academic Search

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

Daniel Delfosse; Gilles Pageau; Roger Bennett; Anoush Poursartip

1993-01-01

82

Mark III confirmatory test program: one-third scale pool swell impact tests, Test Series 5805  

Microsoft Academic Search

A series of 51 blowdown tests was performed in support of the Mark III ; pressure suppression concept with particular emphasis on the effect of pool swell ; impact on structures located above the suppression pool. The integrated steam ; generator and drywell of the Pressure Suppression Test Facility was used to ; accelerate the water mass in the one-third

T. R. McIntyre; W. J. Bilanin; M. A. Ross; J. E. Torbeck

1975-01-01

83

Instrumented impact testing at high velocities  

NASA Astrophysics Data System (ADS)

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.

Delfosse, Daniel; Pageau, Gilles; Bennett, Roger; Poursartip, Anoush

84

Instrumented impact testing at high velocities  

SciTech Connect

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.

Delfosse, D.; Pageau, G.; Bennett, R.; Poursartip, A. (British Columbia Univ., Vancouver (Canada) Defence Research Establishment Valcartier, Courcelette (Canada))

1993-01-01

85

SMALL-SCALE IMPACT SENSITIVITY TESTING ON EDC37  

SciTech Connect

EDC37 was tested at LLNL to determine its impact sensitivity in the LLNL's drop hammer system. The results showed that impact sensitivities of the samples were between 86 cm and 156 cm, depending on test methods. EDC37 is a plastic bonded explosive consisting of 90% HMX, 1% nitrocellulose and binder. We recently conducted impact sensitivity testing in our drop hammer system and the results are presented in this report.

HSU, P C; HUST, G; MAIENSCHEIN, J L

2008-04-28

86

Full-scale aircraft impact test for evaluation of impact forces: Part 1, Test plan, test method, and test results  

Microsoft Academic Search

One of the factors considered in the design of critical concrete structures is the estimation of the global elasto-plastic structural response caused by the accidental impact of an aircraft. To estimate the response of the structure, the impact force (the force versus time relationship) must be known. Previous analytical studies have derived the forcing function using the impact velocity of

W. A. von Riesemann; R. L. Parrish; D. C. Bickel; S. R. Heffelfinger; K. Muto; T. Sugano; H. Tsubota; N. Koshika; M. Suzuki; S. Ohrui

1989-01-01

87

Impact Testing of Simulated High-Level Waste Glass Canisters.  

National Technical Information Service (NTIS)

Three Savannah River Laboratory reference high-level waste canisters were subjected to impact tests at the Pacific Northwest Laboratory in Richland, Washington, in June 1983. The purpose of the test was to determine the integrity of the canister, nozzle, ...

M. E. Peterson J. M. Alzheimer S. C. Slate

1985-01-01

88

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...

89

XDT in HTPB propellant from steel flyer plate impact tests  

Microsoft Academic Search

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

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

2000-01-01

90

Responses of side impact dummies in sled tests  

Microsoft Academic Search

Sled tests were conducted at a velocity of 6.7m\\/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

Narayan Yoganandan; Frank A. Pintar

2005-01-01

91

Design of an impact abrasion testing machine  

Microsoft Academic Search

By using a cam-flat follower-impact shaft with a crank-flat rotating anvil system, the machine to be described can create various impact abrasion conditions to simulate a large range of industrial situations encountered in this field. The main features of the machine are the long working life of the flat rotating anvil, which works in the same way as that of

D. Zhang; P. R. Beeley; A. J. Baker

1994-01-01

92

Mechanical modeling and analysis of the impact testing of wire  

Microsoft Academic Search

A new experimental test method and its associated mechanics description is reported for the instrumented impact of small diameter rod and wire. The use of this test lies in its ability to quickly and effectively measure impact fracture energy at various dynamic strain rates while indirectly providing a measure of the material's dynamic yield stress. The basic outline of the

G. Laird; K. K. Schrems

1997-01-01

93

AMF and FIAT ESVs - Vehicle-to-Vehicle Impact Tests.  

National Technical Information Service (NTIS)

A 75-mph closure front-to-front impact test and a 60-mph front-to-rear impact test were conducted between a 1500-pound class Fiat Experimental Safety Vehicle (ESV) and a 5200-pound AMF Inc. ESV, to determine the structural response of the Fiat ESV when in...

1973-01-01

94

Impact Damage in Sandwich Composite Structures From Gas Gun Tests  

Microsoft Academic Search

The paper studies the High Velocity Impact (HVI) response of aircraft structures by means of gas gun impact tests and post-test\\u000a NDE evaluation. The scope of the activity comprises structural components such as stringer stiffened composite panels and\\u000a a range of composite sandwich structures, with projectiles such as ice, synthetic birds, runway debris and tyre\\/rim debris.\\u000a The tests and simulations

Nathalie Toso-Pentecote; Alastair Johnson

95

The NASA JSC Hypervelocity Impact Test Facility (HIT-F)  

NASA Technical Reports Server (NTRS)

The NASA Johnson Space Center Hypervelocity Impact Test Facility was created in 1980 to study the hypervelocity impact characteristics of composite materials. The facility consists of the Hypervelocity Impact Laboratory (HIRL) and the Hypervelocity Analysis Laboratory (HAL). The HIRL supports three different-size light-gas gun ranges which provide the capability of launching particle sizes from 100 micron spheres to 12.7 mm cylinders. The HAL performs three functions: (1) the analysis of data collected from shots in the HIRL, (2) numerical and analytical modeling to predict impact response beyond test conditions, and (3) risk and damage assessments for spacecraft exposed to the meteoroid and orbital debris environments.

Crews, Jeanne L.; Christiansen, Eric L.

1992-01-01

96

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

Microsoft Academic Search

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

S. K. Chidester; C. M. Tarver; A. H. Depiero; R. G. Garza

2000-01-01

97

The impact toughness characteristics of steel wire-reinforced polymer composites  

Microsoft Academic Search

In this paper, the impact toughness properties of fine steel wire-reinforced polymer matrix composites is presented and discussed. Strips of the polymer composite is attached on to a standard Charpy V-notch impact specimen. Temperature influences, in the range from cryogenic (?190°C) to ambient (30°C) on the impact toughness properties of the polymer composites are highlighted in light of energy absorbed

T. S Srivatsan; P. C Lam; J Krause

1999-01-01

98

Impact of Testing on Hispanic Teacher Candidates.  

ERIC Educational Resources Information Center

This article examines the effect of the Pre-Professional Skills Test (P-PST) and the Examination for the Certification of Teachers in Texas (ExCET) on Hispanics and Blacks and the tests' implications for the future pool of minorities in preservice teacher education programs and in the teaching force. (JL)

Zapata, Jesse T.

1988-01-01

99

Vehicle Impact Testing of Lightweight Lighting Standards.  

National Technical Information Service (NTIS)

The results of seven full-scale vehicular crash tests on 35-ft-high breakaway lighting standards with 20-ft-long mast arms are presented and compared with the recommended crash test criteria in NCHRP 230 and with the new 1985 AASHTO standard specification...

A. Abghari R. L. Stoughton J. P. Dusel

1988-01-01

100

Psychosocial impact of presymptomatic genetic testing for transthyretin amyloidotic polyneuropathy  

Microsoft Academic Search

Presymptomatic genetic testing of an untreatable disease raises clinical, ethical, legal and psychosocial questions. Investigations in specific disorders are needed to help in understanding the motivation for and the impact of genetic testing in the lives of persons at risk for these diseases. Here, we performed a longitudinal study to investigate the psychological consequences of presymptomatic genetic testing on people

Anita Graceffa; Massimo Russo; Gian Luca Vita; Antonio Toscano; Roberto Dattola; Corrado Messina; Giuseppe Vita; Anna Mazzeo

2009-01-01

101

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2010 CFR

...to be approved, including any support blocks, with the battery cells completely assembled. If used, support blocks must contact only the filler material or partitions between the individual cells. At the test temperature range of...

2009-07-01

102

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2010 CFR

...to be approved, including any support blocks, with the battery cells completely assembled. If used, support blocks must contact only the filler material or partitions between the individual cells. At the test temperature range of...

2010-07-01

103

Live fire testing requirements - Assessing the impact  

SciTech Connect

Full-up live-fire testing (LFT) of aircraft configured for combat is evaluated in terms of the practical implications of the technique. LFT legislation requires the testing of tactical fighters, helicopters, and other aircraft when they are loaded with the flammables and explosives associated with combat. LFT permits the study of damage mechanisms and battle-damage repair techniques during the design phase, and probability-of-kill estimates and novel systems designs can be developed based on LFT data.

O'Bryon, J.F. (DOD, Office of the Secretary of Defense, Washington, DC (United States))

1992-08-01

104

Low power arcjet test facility impacts  

Microsoft Academic Search

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

W. Earl Morren; Paul J. Lichon

1992-01-01

105

Impact of uncertainty on modeling and testing  

NASA Technical Reports Server (NTRS)

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.

Coleman, Hugh W.; Brown, Kendall K.

1995-01-01

106

Numerical Simulations of Impact Tests on a Rigid Wall.  

National Technical Information Service (NTIS)

The behavior at impact of steel 30NCD16 is evaluated using the isothermal Johnson-Cook and Lindholm dynamic models. The numerical simulation of the impact tests against a rigid wall and the comparison to the experimental results highlight the interest of ...

D. Bois A. Grave M. L. Meyniel

1987-01-01

107

Measuring and Testing the Impact of News on Volatility  

Microsoft Academic Search

This paper introduces the News Impact Curve to measure how new information is incorporated into volatility estimates. A variety of new and existing ARCH models are compared and estimated with daily Japanese stock return data to determine the shape of the News Impact Curve. New diagnostic tests are presented which emphasize the asymmetry of the volatility response to news. A

Robert F. Engle; Victor K. Ng

1991-01-01

108

LLNL small-scale drop-hammer impact sensitivity test  

SciTech Connect

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.

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

1995-01-01

109

Mechanical Impact Tests of Materials in Oxygen Effects of Contamination.  

National Technical Information Service (NTIS)

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 - cutt...

P. M. Ordin

1980-01-01

110

Selecting Erlang Test Cases Using Impact Analysis  

NASA Astrophysics Data System (ADS)

Refactoring is a commonly used technology in the software development and maintenance process. However refactorings preserve the original behaviour of the system, developers want to be convinced about that, thus they retest the software after some modifications. Software testing is said to be the most expensive part of the lifecycle of software systems. Therefore our research focuses on selecting test cases affected by refactorings and have to be retested after the transformation. We describe the used mechanism in case of a dynamically typed functional programming language, Erlang.

Bozó, István; Tóth, Melinda

2011-09-01

111

Low Power Arcjet Test Facility Impacts.  

National Technical Information Service (NTIS)

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 perfor...

W. E. Morren P. J. Lichon

1992-01-01

112

Low-power arcjet test facility impacts  

Microsoft Academic Search

Performance characterizations of a flight-type 1.4 kW arcjet system were conducted. 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

W. E. Morren; Paul J. Lichon

1992-01-01

113

A Comparison of Quasi-Static Indentation Testing to Low Velocity Impact Testing  

NASA Technical Reports Server (NTRS)

The need for a static test method for modeling low-velocity foreign object impact events to composites would 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 carried out and compared. Square specimens of many sizes and thickness were utilized to cover the array of types of low velocity impact events. Laminates with a n/4 stacking sequence were employed since this is by the most 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, contact stresses and both to examine if the static indentation-impact comparisons are valid under the spectrum of damage modes that can be experienced. Comparisons between static indentation and low velocity impact tests were based on the maximum applied transverse load. The dependent parameters examined included dent depth, back surface crack length, delamination area and to a limited extent, 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 can be used to represent a low velocity impact event.

Nettles, Alan T.; Douglas, Michael J.

2001-01-01

114

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

Federal Register 2010, 2011, 2012, 2013

...Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety Administration...concerning a 50th percentile adult male side crash test dummy called the ``ES-2re'' test dummy. The...

2011-06-02

115

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

PubMed

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. PMID:17851998

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

2007-09-01

116

Uptake and Impact of Carrier Testing for Cystic Fibrosis  

Microsoft Academic Search

The first aim of the paper is to review research into the uptake of carrier testing for cystic fibrosis and into the impact of carrier testing on self-esteem, risk perception and reproductive decisions. The second aim is to connect the most important findings to psychological theories and concepts. Thirdly, we infer practical suggestions for genetic counselling. The uptake of genetic

Marleen Decruyenaere; Gerry Evers-Kiebooms; Lieve Denayer; Myriam Welkenhuysen

1998-01-01

117

LLNL small-scale drop-hammer impact sensitivity test  

Microsoft Academic Search

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

L. R. Simpson; M. F. Foltz

1995-01-01

118

Thin hard coatings fracture propagation during the impact test  

Microsoft Academic Search

One of the most significant applications of the impact test is to investigate thin hard coatings fatigue properties. Herein the test conditions and duration up to the film damage initiation, are considered in order to determine the critical stresses associated with the coating fatigue strength. Moreover, the subsequent film damage propagation is a significant mechanism as well, since it refers

K.-D. Bouzakis; A. Siganos; T. Leyendecker; G. Erkens

2004-01-01

119

Computer simulation of two-dimensional impact tests on propellant  

Microsoft Academic Search

Computational simulations were performed of several hazards tests previously carried out by LLNL. The hazards tests consisted of side-on impacts of a propellant cylinder by a massive steel projectile with subsequent blast wave loading from an adjacent explosive charge. The simulations used a dynamic fracture model previously developed by SRI. The computational results showed that whereas the fracture-induced new surface

W. J. Murri; L. Seaman

1983-01-01

120

Taylor impact tests on PBX composites: imaging and analysis  

NASA Astrophysics Data System (ADS)

A series of Taylor impact tests were performed on three plastic bonded explosive (PBX) formulations: PBX 9501, PBXN-9 and HPP (propellant). The first two formulations are HMX-based, and all three have been characterized quasi-statically in tension and compression. The Taylor impact tests use a 500 psi gas gun to launch PBX projectiles (approximately 30 grams, 16 mm diameter, 76 mm long), velocities as high as 215 m/s, at a steel anvil. Tests were performed remotely and no sign of ignition/reaction have been observed to date. Highspeed imaging was used to capture the impact of the specimen onto anvil surface. Side-view contour images have been analyzed using dynamic stress equations from the literature, and additionally, front-view images have been used to estimate a tensile strain failure criterion for initial specimen fracture. Post-test sieve analysis of specimen debris correlates fragmentation with projectile velocity, and these data show interesting differences between composites. Along with other quasi-static and dynamic measurements, Taylor impact images and fragmentation data provide a useful metric for the calibration or evaluation of intermediate-rate model predictions of PBX constituitive response and failure/fragmentation. Intermediate-rate tests involving other impact configurations are being considered.

Graff Thompson, Daria; DeLuca, Racci; Archuleta, Jose; Brown, Geoff W.; Koby, Joseph

2014-05-01

121

Impact Testing of Composites for Aircraft Engine Fan Cases  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

122

Quantitative Impact Testing of Energy Dissipation at Surfaces  

Microsoft Academic Search

Impact testing with nanoscale spatial, force, and temporal resolution has been developed to address quantitatively the response\\u000a of surfaces to impingement of local contact at elevated velocities. Here, an impact is generated by imparting energy to a\\u000a pendulum carrying an indenter, which then swings towards a specimen surface. The pendulum displacement as a function of time\\u000a x(t) is recorded, from

G. Constantinides; C. A. Tweedie; N. Savva; J. F. Smith; K. J. Van Vliet

2009-01-01

123

Impact limiter tests of four commonly used materials and establishment of an impact limiter data base  

SciTech Connect

In designing a package for transporting hazardous or radioactive materials, there are a number of components whose design can lead to the success or failure to meet regulatory requirements for Type B packages. One of these components is the impact limiter. The primary purpose of the impact limiter is to protect the package and its contents from sudden deceleration. It can also act as a thermal barrier. The package is protected by the impact limiter`s ability to act as an energy absorber. The crush strength of most impact limiting materials is determined by a standard quasistatic (QS) method. However it has been observed that there are a number of factors that affect crush strength. The material being used as an impact limiter may appear incompressible because of one or more of these factors. Factors that determine compressive strength of impact limiter materials are; the material density; the thickness of the impact limiter material. There must be adequate material to absorb the impact and not go into lockup, lockup up occurs when the free volume of the material is eliminated and the crush strength sharply increases; the angle of impact; and the loading rate and operating temperature. All of these are interactive and therefore difficult to model. It is the intent of tests discussed in this paper to determine the dependency of crush strength to loading rate and angle of impact to the basic grain direction of two different densities of four impact limiting materials.

McMurtry, W.M.; Hohnstreiter, G.F.

1995-12-31

124

Hypervelocity impact testing of Shuttle Orbiter thermal protection system tiles  

NASA Technical Reports Server (NTRS)

Results are presented from a series of 22 hypervelocity impact tests carried out on the thermal protection system (TPS) for the Shuttle Orbiter. Both coated and uncoated low-density (0.14 g/cu cm) LI-900 and high-density (0.35 g/cu cm) LI-2200 tiles were tested. The results are used to develop the penetration and damage correlations which can be used in meteoroid and debris hazard analyses for spacecraft with a ceramic tile TPS. It is shown that tile coatings act as a 'bumper' to fragment the impacting projectile, with thicker coating providing increased protection.

Christiansen, Eric L.; Ortega, Javier

1990-01-01

125

The Impact of Personality and Test Conditions on Mathematical Test Performance  

ERIC Educational Resources Information Center

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…

Hayes, Heather; Embretson, Susan E.

2013-01-01

126

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

NASA Astrophysics Data System (ADS)

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.

Guruprasad, Pradosh

127

Apparatus for Hot Impact Testing of Material Specimens  

NASA Technical Reports Server (NTRS)

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

Pawlik, Ralph J.; Choi, Sung R.

2006-01-01

128

Impact Testing of a Stirling Converter's Linear Alternator  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

129

Impact testing of a Stirling convertor's linear alternator  

NASA Astrophysics Data System (ADS)

The U.S. Department of Energy (DOE), in conjunction with 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. .

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

2002-01-01

130

Vibration testing of impact-damaged composite laminates  

NASA Technical Reports Server (NTRS)

A new test is described that can be used to measure changes in the vibration properties of impact damaged composite materials. Impact-induced delamination was observed to significantly affect natural frequencies of vibration and damping properties in cross-ply graphite/epoxy laminates. Natural frequencies are shown to drop by as much as half of their original value, and modal damping ratios can increase by a factor of up to eight when large amounts of damage are present. A simple finite element model of the damaged impact specimens was used to predict the effect of delamination on certain vibration properties. A comparison of the finite element calculations with the experimental measurements suggests that delamination was the dominant mechanism of flexural stiffness loss resulting from the transverse impact.

Grady, Joseph E.; Meyn, Erwin H.

1989-01-01

131

The potential impact of pharmacogenetic testing on medication adherence.  

PubMed

Poor medication adherence is a well-known problem, particularly in patients with chronic conditions, and is associated with significant morbidity, mortality and health-care costs. Multi-faceted and personalized interventions have shown the greatest success. Pharmacogenetic (PGx) testing may serve as another tool to boost patients' confidence in the safety and efficacy of prescribed medications. Here, we consider the potential impact (positively or negatively) of PGx testing on medication-taking behavior. PMID:23999596

Haga, S B; LaPointe, N M A

2013-12-01

132

IMPACT: integrated multiprogram platform for analyses in ConTest.  

PubMed

In this paper, we introduce a new Graphical User Interface that estimates evolutionary rates on protein sequences by assessing changes in biochemical constraints. We describe IMPACT, a platform-independent (tested in Linux, Windows, and MacOS), easy to install software written in Java. IMPACT integrates the use of a built-in multiple sequence alignment editor, with programs that perform phylogenetic and protein structure analyses (ConTest, PhyML, ATV, and Jmol) allowing the user to quickly and efficiently perform evolutionary analyses on protein sequences, including the detection of selection (negative and positive) signatures at the amino acid scale, which can provide fundamental insight about species evolution and ecological fitness. IMPACT provides the user with a working platform that combines a number of bioinformatics tools and utilities in one place, transferring information directly among the various programs and therefore increasing the overall performance of evolutionary analyses on proteins. PMID:21414966

Maldonado, Emanuel; Dutheil, Julien Y; da Fonseca, Rute R; Vasconcelos, Vítor; Antunes, Agostinho

2011-01-01

133

End-on radioisotope thermoelectric generator impact tests  

SciTech Connect

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.

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

1997-01-01

134

Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing  

NASA Technical Reports Server (NTRS)

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.

Littell, Justin D.

2010-01-01

135

Impact Testing of Centrifugally Cast Canisters of Simulated Waste Glass.  

National Technical Information Service (NTIS)

Four simulated high-level waste canisters supplied by EG and G Idaho, Inc. of Idaho Falls, Idaho, were subjected to impact tests at the Pacific Northwest Laboratory in Richland, Washington. The canister design was similar to the most recent Savannah River...

M. E. Peterson J. M. Alzheimer

1984-01-01

136

Impact testing of centrifugally cast canisters of simulated waste glass  

Microsoft Academic Search

Four simulated high-level waste canisters supplied by EG and G Idaho, Inc. of Idaho Falls, Idaho, were subjected to impact tests at the Pacific Northwest Laboratory in Richland, Washington. The canister design was similar to the most recent Savannah River Laboratory (SRL) reference dewsign for the Defense Waste Processing Facility. Three of the canister bodies were fabricated out of a

M. E. Peterson; J. M. Alzheimer

1984-01-01

137

Comparative Impact Tests on Metal Honeycomb Sandwich Structures.  

National Technical Information Service (NTIS)

Impact test results were carried out on metal honeycomb sandwich structures to compare the present structure (i.e. aileron trailing edges of 0.3 mm, 5.322/9 faces and honeycomb 5.453/2, bonded with FM 123-5) to structures with heavier faces and honeycomb....

J. Koetsier

1975-01-01

138

Studies of Abrasive Wear in a Modified Impact Testing Machine.  

National Technical Information Service (NTIS)

Single tip abrasive wear was simulated in a conventional impact test machine modified by attaching a cemented carbide tip radially to the hammer. The swinging hammer produced a groove in the horizontal surface of low carbon steel of specimens, supported b...

U. Bryggman S. Hogmark O. Vingsbo

1976-01-01

139

Sloshing roof impact tests of a rectangular tank  

NASA Astrophysics Data System (ADS)

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.

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

140

A drop tower for controlled impact testing of biological tissues.  

PubMed

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. PMID:16876457

Burgin, Leanne V; Aspden, Richard M

2007-05-01

141

Toughness characterization by small specimen test technique for HIPed joints of F82H steel aiming at first wall fabrication in fusion  

NASA Astrophysics Data System (ADS)

Reduced activation ferritic/martensitic steels (RAFMs), such as F82H steels, have been developed as candidates of structural materials for fusion. In the design of a fusion reactor, cooling channels are built in the first wall of the blanket. One large issue is to determine how to join rectangular tubes to thin panels to fabricate the first wall. Hot Isostatic Pressing (HIPing) is a solution to solve the issue. Because of the thin HIPed walls of the channels, the specimen size for inspection of HIPed interface is limited. In the present research, Small Specimen Test Techniques (SSTT) are screened for the destructive toughness investigation technique of HIPed F82H joints. 1/3 size Charpy V-notch impact (1/3 CVN) and small punch (SP) tests are employed for the present research. The toughness of the HIPed joints is strongly affected by various surface finishing of specimens treated previous to the HIPing. In the present research, several kinds of HIPed joints were surface finished by different methods and investigated by 1/3 CVN impact test. The HIPed F82H joints had different toughness ranging from 20% to 70% of the toughness of the F82H base metal. The SP test is also available for the investigation of toughness change by the HIPing. The sensitivity of 1/3 CVN impact test against toughness change was better than the SP test, it revealed that the SP test has some limitations.

Kishimoto, H.; Ono, T.; Sakasegawa, H.; Tanigawa, H.; Kohno, Y.; Kohyama, A.

2013-09-01

142

Low-velocity impact tests on fibrous composite sandwich structures  

NASA Technical Reports Server (NTRS)

The effect of low-velocity projectile impact on the load-carrying ability of the composite sandwich structural components is investigated experimentally, the impact simulating the damage caused by runway debris and the accidental dropping of hand tools during servicing on secondary aircraft structures made with composites. The sandwich-type beam specimens were fabricated with graphite/epoxy face sheets, aluminum honeycomb core, and a steel (back) plate. A four-point beam-loading apparatus was used, and the ultimate strength, ultimate strain, and residual strength of the composites were determined. A faired curve is presented indicating the lower bound of the failure threshold for each of the laminate configurations tested in compression and tension as a function of the projectile impact energy. It is shown that strength degradation due to impact is dependent on the laminate configuration and the fiber/matrix combination. The laminates having more angle plies near the impact surface and unidirectional plies elsewhere seem to show extensive interply and intraply fiber delaminations at failure relative to the laminates with a cross-ply on the impact surface.

Sharma, A. V.

1981-01-01

143

Hypervelocity Impact Test Facility: A gun for hire  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

144

Impact Tensile Testing of Stainless Steels at Various Temperatures  

SciTech Connect

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.

D. K. Morton

2008-03-01

145

Hydrodynamic impact analysis and testing of an unmanned aerial vehicle  

NASA Astrophysics Data System (ADS)

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.

Bird, Isabel

146

Space Shuttle Main Engine Debris Testing Methodology and Impact Tolerances  

NASA Technical Reports Server (NTRS)

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.

Gradl, Paul R.; Stephens, Walter

2005-01-01

147

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

SciTech Connect

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.

Martins, Marcelo [Industrial Manager of SULZER BRASIL S/A and Professor of the Centro Universitario Salesiano de Sao Paulo (UNISAL) at Americana, SP (Brazil)], E-mail: marcelo.martins@sulzer.com; Forti, Leonardo Rodrigues Nogueira [Materials Engineer at UFSCar, Federal University of Sao Carlos (Brazil)], E-mail: leornf@yahoo.com.br

2008-02-15

148

Effects of microstructure on inverse fracture occurring during drop-weight tear testing of high-toughness X70 pipeline steels  

NASA Astrophysics Data System (ADS)

The effects of microstructure on inverse fracture occurring in the hammer-impacted region were analyzed after conducting a drop-weight tear test (DWTT) on high-toughness pipeline steels. Three kinds of steels were fabricated by varying the alloying elements, and their microstructures were varied by the rolling conditions. The pressed-notch (PN) or chevron-notch (CN) DWTT and Charpy V-notch (CVN) impact tests were conducted on the rolled steel specimens, and the results were discussed in comparison with the data obtained from CVN tests of prestrained specimens. In the hammer-impacted region of the DWTT specimens, abnormal inverse fracture having a cleavage fracture mode appeared, and the inverse fracture area correlated well with the upper-shelf energy (USE) obtained from the CVN test and with the grain size. The steel specimens having a higher USE or having coarse polygonal ferrite tended to have a larger inverse fracture area than those having a lower USE or having fine acicular ferrite. This was because steels having a higher impact absorption energy required higher energy for fracture initiation and propagation during the DWTT. These results were confirmed by the CVN data of prestrained steel specimens.

Hwang, Byoungchul; Kim, Yang Gon; Lee, Sunghak; Kim, Nack J.; Yoo, Jang Yong

2005-02-01

149

Simulated hail impact testing of photovoltaic solar panels  

NASA Technical Reports Server (NTRS)

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.

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

1978-01-01

150

Radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

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.

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

1998-12-31

151

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

NASA Astrophysics Data System (ADS)

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. .

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

2000-04-01

152

Impact Force Characteristics of Package-level Solder Joints Under Ball Impact Test  

Microsoft Academic Search

The ball impact test is developed as a package-level measure for the board-level drop reliability of solder joints in the sense that it leads to fracturing of solder joints around intermetallics, similar to that from a board-level drop test. We investigate numerically in this paper the effect of yield stress variations of solder alloy on transient structural responses of a

Chang-Lin Yen; Yi-Shao Lai

2006-01-01

153

Quasi-static and impact tests of honeycomb  

NASA Astrophysics Data System (ADS)

In this paper the quasi-static and instrumented compression impact testing of two kinds of aluminum-alloy honeycomb are reported. Those two types of honeycomb called Hard (H) and Soft (S) were tested. The specimens in cubical form of dimensions 60 mm × 60 mm × 120 mm were made with and without the front aluminum alloy plates (thickness 1.0 mm) cemented to the specimen two faces. The tests have been performed along the largest dimension that is 120 mm, which is parallel to the aluminum sheet profiles forming the honeycomb. A wide range of compression velocities from the quasi-static rate (V0 = 10 mm/min) to the highest impact velocity V6 = 120 m/s were applied. The total number of velocities applied, including the quasi-static loading, was six. Several series of tests were performed. The first two were carried out with the flat-ended strikers of specific masses, which were adequate to each impact velocity. In order to obtain an adequate displacement of crushing the condition of constant kinetic energy of a striker was assumed. In addition, conical strikers were applied with the cone angle 120circ. Application of the direct impact arrangement along with properly instrumented 9m long Hopkinson bar of Nylon with diameter 80 mm enabled for a wave dispersion analysis to be applied. The crushing force versus time could be exactly determined at the specimen-bar interface by application of an inverse technique along with the theory of visco-elastic wave propagation.

Gary, G.; Klepaczko, J. R.

2006-08-01

154

Cleavage delamination in impact tested warm-rolled steel  

Microsoft Academic Search

Cleavage delaminations or separations have been observed on fracture surfaces of impact specimens made from rolled steel pipe\\u000a and plate products. These delaminations appear as cleavage cracks lying parallel to the plane of rolling. Depending primarily\\u000a on the test temperature and extent of rolling, four fracture modes have been reported: ductile, transgranular, ductile with\\u000a cleavage delaminations, and transgranular with cleavage

D. L. Bourell

1983-01-01

155

Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials  

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

156

Testing and simulation of composite laminates under impact loading  

NASA Astrophysics Data System (ADS)

Owing to their high stiffness-to-weight and high strength-to-weight ratios, fiber-reinforced polymer-matrix composite laminates are excellent materials for high-performance structures. However, their properties in the thickness direction are very poor as they are weakly bonded by polymeric matrices through laminate interfaces. Accordingly, when a composite laminate is subjected to impact loading, high interlaminar stresses along with the low interlaminar strengths could easily result in interlaminar damage such as delamination. This thesis investigated the response of composite laminates under low-velocity impact and presented numerical techniques for impact simulation. To begin with, instrumented drop-weight impacts ranging from subperforation to perforation levels were introduced to composite laminates having various dimensions and thicknesses. Damaged composite laminates were then subjected to compression-after-impact tests for evaluations of residual properties. Experimental results revealed that perforation was an important damage milestone since impact parameters such as peak force, contact duration, maximum deflection and energy absorption, and residual properties such as compressive stiffness, strength and energy absorption all reached critical levels as perforation took place. It was also found that thickness played a more important role than in-plane dimensions in perforation process. In order to understand more about the relationship between laminate thickness and perforation resistance and to present an economical method to improve perforation resistance, thick laminated composite plates and their assembled counterparts were investigated and compared. An energy profile correlating the impact energy and absorbed energy at all energy levels for each type of composite plates investigated was established and found to be able to address the relationship between energy and damage. Experimental results concluded that increasing thickness was more efficient than improving assembling stiffness in raising perforation resistance. As a first step to simulate composite response to impact loading, LS-DYNA3D was used for numerical analysis. However, due to its inability to describe interlaminar stresses, no delamination simulation could be achieved. As delamination played a very important role in damage process, a computational scheme capable of identifying interlaminar stresses and considering both numerical accuracy and computational efficiency was required for impact simulation. Accounting for interlaminar shear stress continuity and having degrees of freedom independent of layer number, a laminate theory named Generalized Zigzag Theory was formulated into a finite element subroutine and integrated into ABAQUS code. The computational scheme was able to present reasonable interlaminar shear stresses via an updated Lagragian algorithm. Combining the calculated interlaminar stresses with a delamination failure criterion, the computer program was able to predict the response of composite laminates up to the onset of delamination. Further computational simulation involving all damage modes should be considered in future studies.

Dang, Xinglai

157

Shape Distribution of Fragments from Microsatellite Impact Tests  

NASA Technical Reports Server (NTRS)

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.

Liou, J.C.; Hanada, T.

2009-01-01

158

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

NASA Technical Reports Server (NTRS)

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.

Vassilakos, Gregory J.; Hardy, Robin C.

2012-01-01

159

Cycom 977-2 Composite Material: Impact Test Results  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

160

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

ERIC Educational Resources Information Center

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…

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

2011-01-01

161

The Impact Hydrocode Benchmark and Validation Project: Results of Validation Tests  

Microsoft Academic Search

We present our first validation tests of a glass sphere impacting water and an aluminum sphere impacting aluminum as part of the collective validation and benchmarking effort from the impact cratering and explosion community.

E. Pierazzo; N. A. Artemieva; E. C. Baldwin; J. Cazamias; R. F. Coker; G. S. Collins; D. A. Crawford; T. Davison; K. A. Holsapple; K. R. Housen; D. G. Korycansky; K. Wünnemann

2008-01-01

162

Verification of constitutive models using the Asay Impact Test  

SciTech Connect

Accurate analysis and the ability to predict the complete response of particulate composite materials requires accurate inelastic constitutive models. However, to be of maximum utility, these inelastic models must be validated using quantifiable experimental results. The Asay Impact Test is an impact experiment that provides the evolution of the two dimensional in-plane displacement field in a specimen undergoing dynamic inelastic deformation. The experimental displacement field may be directed compared with the predicted displacement field from a candidate inelastic constitutive model. In this paper, the authors report comparisons between experimental and predicted displacement fields in the energetic particulate composite material PBX-9501 during dynamic deformation, and describe the experiment and the constitutive modeling approach.

Haberman, K.S.; Bennett, J.G.

1998-09-01

163

Obsolete Cask Program: end-on drop tests with and without an impact limiter and the 40-inch puncture test  

Microsoft Academic Search

The Heavy Water Component Test Reactor (HWCTR) cask was subjected to three impact tests that involved two 9-m drops and one 1-m drop onto a solid, essentially unyielding surface. The cask, weighing about 21,000 kg and fitted with a balsa impact limiter over the closure end, was dropped initially in a vertical position so that the impact limiter would strike

L. B. Shappert; W. L. Bryan; R. C. Muller; K. K. Chipley; J. H. Evans; R. D. Seagren; W. D. Box

1977-01-01

164

Impact of looping on middle school science standardized achievement tests  

NASA Astrophysics Data System (ADS)

Looping may be defined as a teacher remaining with a group of students for multiple academic years. In this quantitative study, looping was examined as a factor on science achievement. State-wide eighth grade school level 2010 Pennsylvania System of School Assessment (PSSA) data were used. By responding to a mailing, school administrators indicated if 2010 eighth grade students had or had not been looped. The schools' percentage of advanced and proficient Science PSSA data were used to determine if the independent variable had a significant impact on science achievement. The results of the independent t-test analysis suggest that looping does not contribute to science achievement for this study sample.

Barger, Tammy M.

165

Water impact testing of a filament wound case  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

166

Antenatal noninvasive DNA testing: clinical experience and impact.  

PubMed

Background?Nearly two decades ago, the discovery of circulating cell-free fetal DNA in maternal blood created a paradigm shift in prenatal testing. Recent advances in DNA sequencing technology have facilitated the rapid translation of DNA-based testing into clinical antenatal care. Content?In this review, we summarize the technical approaches and current clinical applications of noninvasive testing using cell-free DNA in maternal plasma. We discuss the impact of these tests on clinical care, outline proposed integration models, and suggest future directions for the field. Summary?The use of cell-free DNA in maternal blood for the detection of fetal rhesus D antigen status, fetal sex, and common whole chromosomal aneuploidies is now well established, although testing for aneuploidy is still considered screening and not diagnostic. Further advances in technology and bioinformatics may see future clinical applications extend to the noninvasive detection of fetal subchromosomal aneuploidy, single gene disorders, and the entire fetal genome. PMID:24683075

Ferres, Millie A; Hui, Lisa; Bianchi, Diana W

2014-08-01

167

Dynamic Impact Analyses and Tests of Concrete Overpacks - 13638  

SciTech Connect

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)

Lee, Sanghoon; Cho, Sang-Soon; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)] [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-07-01

168

The DT-19 container design, impact testing and analysis  

SciTech Connect

Containers used by the Department of Energy (DOE) for the transport of radioactive material components, including components and special assemblies, are required to meet certain impact and thermal requirements that are demonstrated by performance or compliance testing, analytical procedures or a combination of both. The Code of Federal Regulations (CFR) Part 49, Section 173.7(d) stipulates that, {prime}Packages (containers) made by or under direction of the US DOE may be used for the transportation of radioactive materials when evaluated, approved, and certified by the DOE against packaging standards equivalent to those specified in 10 CFR Part 71. This paper describes the details of the design, analysis and testing efforts undertaken to improve the overall structural and thermal integrity of the DC-19 shipping container.

Aramayo, G.A. [Oak Ridge National Lab., TN (United States); Goins, M.L. [Oak Ridge Y-12 Plant, TN (United States)

1995-12-01

169

Controlled Impact Demonstration instrumented test dummies installed in plane  

NASA Technical Reports Server (NTRS)

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 passenger compartment. Before the final flight on December 1, 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

1984-01-01

170

Impact properties of irradiated HT9 from the fuel duct of FFTF  

NASA Astrophysics Data System (ADS)

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 (?DBTT) 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 ?DBTT data from different studies were compared.

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

2012-02-01

171

Method of testing gear wheels in impact bending  

SciTech Connect

Chemicothermal treatment processes are widely used in engineering to improve the working lives of important components, of which the most common is nitrocementation. That process has been applied at the Volga Automobile Plant mainly to sprockets in gear transmissions, which need high hardness and wear resistance in the surfaces with relatively ductile cores. Although various forms of chemicothermal treatment are widely used, there has been no universal method of evaluating the strengths of gear wheels. Standard methods of estimating strength ({sigma}{sub u}, {sigma}{sub t}, {sigma}{sub b}, and hardness) have a major shortcoming: They can determine only the characteristics of the cores for case-hardened materials. Here we consider a method of impact bending test, which enables one to evaluate the actual strength of gear teeth.

Tikhonov, A.K.; Palagin, Y.M.

1995-05-01

172

High-speed bend test method and failure prediction for drop impact reliability  

Microsoft Academic Search

The objective of this study is to obtain experimental failure models governing solder joint failure during drop impact testing of board assemblies. A high-speed bend test was developed to perform displacement-controlled bend test of board assemblies at the high flexing frequencies of drop impact. These test frequencies and amplitudes are not achievable by conventional universal testers. Experimental data was obtained

S. K. W. Seah; E. H. Wong; Y. W. Mai; R. Rajoo; C. T. Lim

2006-01-01

173

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

NASA Technical Reports Server (NTRS)

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.

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

2008-01-01

174

Control and evaluation of particle impact conditions in a sand erosion test facility  

Microsoft Academic Search

For the prediction of actual damage to plant component materials and for making the erosion mechanisms clear, it is important to control and to evaluate the particle impact conditions in a testing facility. A sand blast type erosion test rig, which can achieve the particle impact velocities up to 135ms?1 and a wide range of impact angles has been constructed.

Y. I Oka; M Nishimura; K Nagahashi; M Matsumura

2001-01-01

175

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

PubMed

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

Cazelles, Bernard; Cazelles, Kévin; Chavez, Mario

2014-02-01

176

A Study of Component-Level Measure of Board-Level Drop Impact Reliability by Ball Impact Test  

Microsoft Academic Search

This paper presents a study of the resistance of solder joints to failure when subjected to strain rates that simulate the conditions of drop impact on a portable electronic product. Two test methods are used in this study: board-level drop\\/shock test (BLDT) and component-level ball impact test (BIT). The performance of 12 material combinations consisting of 6 solder alloys and

Yi-Shao Lail; E. H. Wong; R. Rajoo; S. K. W. Seah; C. S. Selvanayagam; W. D. van Driel; J. F. J. M. Caers; X. J. Zhao; N. Owens; L. C. Tan; M. Leoni; P. L. Eu

2008-01-01

177

49 CFR 572.136 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Knees and knee impact test procedure. 572.136 Section 572.136...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136...

2013-10-01

178

49 CFR 572.126 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 false Knees and knee impact test procedure. 572.126 Section 572.126 Transportation...OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Six-year-old Child Test Dummy, Beta Version § 572.126 Knees...

2013-10-01

179

49 CFR 572.176 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Knees and knee impact test procedure. 572.176 Section 572.176...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III 10-Year-Old Child Test Dummy (HIII-10C) § 572.176 Knees...

2013-10-01

180

Measurement of Satellite Impact Test Fragments for Modeling Orbital Debris  

NASA Technical Reports Server (NTRS)

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.

Hill, Nicole M.

2009-01-01

181

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

ERIC Educational Resources Information Center

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…

Lakin, Joni M.

2014-01-01

182

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

National Technical Information Service (NTIS)

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 initiat...

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

2001-01-01

183

Test rig design and experimental results of coated systems under impact abrasion conditions  

Microsoft Academic Search

The design of a wear test apparatus for combining the effects of impact and abrasion was investigated for testing coated and uncoated materials. Tests consisting of abrasion, impact and their combined effects were carried out on thermally sprayed WC?Co and Ni?Cr coated aluminum and mild steel and compared to uncoated samples. The abrading reciprocating stylus, whose velocity continually changed along

D. M. Kennedy; M. S. J. Hashmi

1996-01-01

184

Effect of humidity on pedestrian legform impactor-to-car bumper impact test results  

Microsoft Academic Search

The effect of humidity on the measured injury criteria of the Transport Research Laboratory (TRL) legform impactor in the bumper impact test was evaluated. The following investigations were conducted in two different humidity conditions – 30% and 60% relative humidity (RH) environments. First, dynamic certification tests were conducted. Second, legform impactor-to-bumper impact tests using two sedan cars were conducted to

Yasuhiro Matsui; Shunsuke Takagi

2011-01-01

185

Effect of humidity on pedestrian legform impactor-to-car bumper impact test results  

Microsoft Academic Search

The effect of humidity on the measured injury criteria of the Transport Research Laboratory (TRL) legform impactor in the bumper impact test was evaluated. The following investigations were conducted in two different humidity conditions – 30% and 60% relative humidity (RH) environments. First, dynamic certification tests were conducted. Second, legform impactor-to-bumper impact tests using two sedan cars were conducted to

Yasuhiro Matsui; Shunsuke Takagi

2012-01-01

186

GA-4/GA-9 honeycomb impact limiter tests and analytical model.  

National Technical Information Service (NTIS)

General Atomics (GA) has a test program underway to obtain data on the behavior of a honeycomb impact limiter. The program includes testing of small samples to obtain basic information, as well as testing of complete 1/4-scale impact limiters to obtain lo...

M. A. Koploy C. S. Taylor

1991-01-01

187

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

NASA Technical Reports Server (NTRS)

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.

Nettles, A. T.

1990-01-01

188

The Impact of Learner Variables on Language Test Performance.  

ERIC Educational Resources Information Center

Looks at how the learner variables of age, sex, language background, high school graduation status, and length of stay in the United States affect performance on six English as a second language tests: two cloze tests, a reading tests, a structure test, and two listening tests. Both test advantage and test favoritism/bias were found. (SED)

Spurling, Steven, Ilyin, Donna

1985-01-01

189

Effects of nonstandard heat treatment temperatures on tensile and Charpy impact properties of carbon-steel casting repair welds  

SciTech Connect

This report discusses carbon steel castings which are used for a number of different components in nuclear power plants, including valve bodies and bonnets. Components are often repaired by welding processes, and both welded components and the repair welds are subjected to a variety of postweld heat treatments (PWHT) with temperatures as high as 899{degrees}C (1650{degrees}F), well above the normal 593 to 677{degrees}C (1100 to 1250{degrees}F) temperature range. The temperatures noted are above the A1 transformation temperature for the materials used for these components. A test program was conducted to investigate the potential effects of such ``nonstandard`` PWHTs on mechanical properties of carbon steel casting welds. Four weldments were fabricated, two each with the shielded-metal-arc (SMA) and flux-cored-arc (FCA) processes,with a high-carbon and low-carbon filler metal in each case. All four welds were sectioned and given simulated PWHTs at temperatures from 621 to 899{degrees}C (1150 to 1650{degrees}F) in increments of 56{degrees}C (100{degrees}F) and for times of 5, 10, 20, and 40 h at each temperature. Hardness, tensile, and Charpy V-notch (CVN) impact tests were conducted for the as-welded and heat-treated conditions.

Nanstad, R.K.; Goodwin, G.M.; Swindeman, M.J. [Oak Ridge National Lab., TN (United States)

1993-04-01

190

Improved Bar Impact Tests using a Photonic Doppler Velocimeter  

Microsoft Academic Search

Bar impacts were used to measure the dynamic strength of glasses. The conventional bar technique has been greatly improved through use of a photonic Doppler velocimeter (PDV) to measure free surface motion. The PDV records a compression pulse corresponding to compressive failure of the impact zone and a spall signal corresponding to tensile failure of the distal end. Best results

Stephan Bless; John Tolman; Scott Levinson; Jeff Nguyen; Ian Polyzois

2009-01-01

191

Sloshing roof impact tests of a rectangular tank.  

National Technical Information Service (NTIS)

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 ...

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

1994-01-01

192

A drop tower for controlled impact testing of biological tissues  

Microsoft Academic Search

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

Leanne V. Burgin; Richard M. Aspden

2007-01-01

193

Low Velocity Impact Testing and Nondestructive Evaluation of Transparent Materials  

Microsoft Academic Search

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.

R. E. Brennan; W. H. Green

2011-01-01

194

LOW VELOCITY IMPACT TESTING AND NONDESTRUCTIVE EVALUATION OF TRANSPARENT MATERIALS  

Microsoft Academic Search

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.

R. E. Brennan; W. H. Green

2011-01-01

195

The Reduction of Adverse Impact in an Employment Setting Using a Short-Term Memory Test  

Microsoft Academic Search

Research suggests that less adverse impact should result from the use of employment tests assessing memory abilities than is obtained from tests assessing cognitive abilities. To test the application of this principle, a Short-Term Memory test and a Reading Comprehension test were administered as part of a selection battery for entry level police. Subjects were 1423 police officer applicants for

Gerald V. Barrett; Ronald G. Carobine; Dennis Doverspike

1999-01-01

196

KRASH Dynamics Analysis Modeling - Transport Airplane Controlled Impact Demonstration Test. Revision.  

National Technical Information Service (NTIS)

A transport airplane Controlled Impact Demonstration (CID) test is analyzed with program KRASH. Prior to modeling the test condition, supporting analysis of both narrow-body and wide-body transport airplane frame segments were modeled with KRASH and compa...

G. Wittlin B. LaBarge

1986-01-01

197

Impact Melt-Pond Scenario Tested During the KRASH 2011 Analogue Mission at Kamestastin Impact Structure  

NASA Astrophysics Data System (ADS)

Discovery Hill is dominated by a wedge-like shaped outcrop of columnar-jointed impact melt rock. Field observations of the hill's morphology, geologic contacts and relative position within the Mistastin impact crater suggest a melt-pond origin.

Chanou, A.; Tornabene, L. L.; Osinski, G. R.; Zanetti, M.; Pickersgill, A. E.; Shankar, B.; Marion, C.; Mader, M. M.; Souders, K. A.; Sylvester, P.; Jolliff, B. L.; Shaver, C.

2012-03-01

198

Hypervelocity Impact Testing of Space Station Freedom Solar Cells  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

199

Insights into correlation between board-level drop reliability and package-level ball impact test  

Microsoft Academic Search

The ball impact test is developed as a package-level measure for the board-level drop reliability of solder joints in the sense that it leads to fracturing of solder joints around the intermetallics, similar to that from a board-level drop test. In this paper, both board-level drop test and package-level ball impact test are examined numerically for solder joints of different

Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

200

A numerical approach towards the correlation between ball impact test and drop reliability  

Microsoft Academic Search

The ball impact test is developed as a package-level measure for the board-level drop reliability of solder joints in the sense that it leads to fracturing of solder joints around the intermetallics, similar to that from a board-level drop test. In this paper, both board-level drop test and package-level ball impact test are examined numerically for solder joints of nine

Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

201

Experimental and numerical analysis of Al6063 duralumin using Taylor impact test  

NASA Astrophysics Data System (ADS)

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.

Kruszka, L.; Anaszewicz, ?.; Janiszewski, J.; Gr?zka, M.

2012-08-01

202

Hybrid III anthropomorphic test device (ATD) response to head impacts and potential implications for athletic headgear testing.  

PubMed

The Hybrid III 50th percentile male anthropomorphic test device (ATD) is the most widely used human impact testing surrogate and has historically been used in automotive or military testing. More recently, this ATD is finding use in applications evaluating athletic helmet protectivity, quantifying head impact dosage and estimating injury risk. But ATD head-neck response has not been quantified in omnidirectional athletic-type head impacts absent axial preload. It is probable that headgear injury reduction that can be quantified in a laboratory, including in American football, boxing, hockey, lacrosse and soccer, is related to a number of interrelated kinetic and kinematic factors, such as head center of gravity linear acceleration, head angular acceleration, head angular velocity, occipito-cervical mechanics and neck stiffness. Therefore, we characterized ATD head-neck dynamic response to direct head impacts in a series of front, oblique front and lateral head impacts. Key findings were: (1) impacts producing highest ATD resultant center of gravity linear acceleration resulted in the lowest resultant occipito-cervical spine bending moment/force. (2) Resultant ATD head angular velocity and angular acceleration did not appear coupled to impact direction at lower impact energy levels; these parameters were coupled at higher energy levels. (3) The ATD had progressively increasing occipito-cervical stiffness in extension, torsion and lateral bending, respectively. Because the ATD neck influenced head and neck impact dosage parameters, testing agencies, manufacturers and researchers should consider using the Hybrid III head form attached to a neck as a means to quantify head and neck injury risks as opposed to systems that do not utilize a neck. This heightened understanding of Hybrid III ATD head-neck response, and consideration of order of stiffest axes in the lateral, oblique and extension directions, respectively, should aid in the development of head and neck injury impact testing standards. PMID:22664692

Bartsch, Adam; Benzel, Edward; Miele, Vincent; Morr, Douglas; Prakash, Vikas

2012-09-01

203

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

204

The Effectiveness of the Component Impact Test Method for the Side Impact Injury Assessment of the Door Trim  

Microsoft Academic Search

The complete evaluation of the side vehicle structure and the occupant protection is only possible by means of the full scale side impact crash test. But, auto part manufacturers such as door trim makers can not conduct the test especially when the vehicle is under the developing process. The main objective of this study is to obtain the design guidelines

Younghan Youn; Jeong-Seo Koo

2008-01-01

205

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

NASA Technical Reports Server (NTRS)

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.

Probst, H B; Mchenry, Howard T

1957-01-01

206

Results of crack-arrest tests on two irradiated high-copper welds  

SciTech Connect

The objective of this study was to determine the effect of neutron irradiation on the shift and shape of the lower-bound curve to crack-arrest data. Two submerged-arc welds with copper contents of 0.23 and 0.31 wt % were commercially fabricated in 220-mm-thick plate. Crack-arrest specimens fabricated from these welds were irradiated at a nominal temperature of 288{degree}C to an average fluence of 1.9 {times} 10{sup 19} neutrons/cm{sup 2} (>1 MeV). Evaluation of the results shows that the neutron-irradiation-induced crack-arrest toughness temperature shift is about the same as the Charpy V-notch impact temperature shift at the 41-J energy level. The shape of the lower-bound curves (for the range of test temperatures covered) did not seem to have been altered by irradiation compared to those of the ASME K{sub Ia} curve. 9 refs., 21 figs., 10 tabs.

Iskander, S.K.; Corwin, W.R.; Nanstead, R.K. (Oak Ridge National Lab., TN (USA))

1990-12-01

207

High-Explosive Field Tests, Explosion Phenomena and Environmental Impacts.  

National Technical Information Service (NTIS)

Methodologies are formulated to predict to magnitudes of high-explosive explosions phenomena for various high-explosive charge sizes and configurations and to relate these magnitudes to impacts on the natural physical and biological environment and on hum...

K. E. Gould

1981-01-01

208

Impact of Equipment Life Characteristics on Missile Test Planning.  

National Technical Information Service (NTIS)

This memorandum examines the impact of prelaunch operations on the probability of successful R and D missile or space system launch and mission completion. To do this, the nature of equipment life characteristics is examined and data presented; secondly, ...

L. T. Mast

1964-01-01

209

Improved Bar Impact Tests using a Photonic Doppler Velocimeter  

NASA Astrophysics Data System (ADS)

Bar impacts were used to measure the dynamic strength of glasses. The conventional bar technique has been greatly improved through use of a photonic Doppler velocimeter (PDV) to measure free surface motion. The PDV records a compression pulse corresponding to compressive failure of the impact zone and a spall signal corresponding to tensile failure of the distal end. Best results were obtained using polished free surfaces, as opposed to retroreflective tape. Use of a graded density film had little effect on strain rate but reduced the peak transmitted stress. The experiments were interpreted with the aid of EMU (peridynamics) calculations. Indications are that the impact end of the bar fails in compression. The bar separates into two sections when the reflected tensile wave arrives at the zone of impact damage. The rear of the bar fails from an inward propagating failure wave that originates at surface flaws.

Bless, Stephan; Tolman, John; Levinson, Scott; Nguyen, Jeff; Polyzois, Ian

2009-06-01

210

A Unified Theory of Impact Crises and Mass Extinctions: Quantitative Tests  

Microsoft Academic Search

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

Michael R. Rampino; Bruce M. Haggerty; Thomas C. Pagano

1997-01-01

211

Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test.  

National Technical Information Service (NTIS)

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 t...

J. W. Forbes C. M. Tarver S. K. Chidester F. Garcia D. W. Greenwood

2000-01-01

212

Experimental and Modeling Studies of Crush, Puncture, and Perforation Scenarios in the Steven Impact Test  

Microsoft Academic Search

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

Kevin S. Vandersall; Steven K. Chidester; Jerry W. Forbes; Frank Garcia; Daniel W. Greenwood; Lori L. Switzer; Craig M. Tarver

2002-01-01

213

Measurement of Low Level Explosives Reaction in Gauged MultiDimensional Steven Impact Tests  

Microsoft Academic Search

The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and 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.

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

2001-01-01

214

Measurement of Low Level Explosives Reaction in Gauged Multidimensional Steven Impact Tests  

Microsoft Academic Search

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

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

2002-01-01

215

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4  

Microsoft Academic Search

Abstract The nonlinear, transient dynamic finite element code, MSC Dytran, was used to simulate an impact 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,

Edwin L. Fasanella

2001-01-01

216

An alternative solder interconnect reliability test to evaluate drop impact performance  

Microsoft Academic Search

With the increased use of mobile phones, navigation systems, PDA's, laptop's and portable gaming devices the drop reliability of microelectronics has become an important parameter. Assessing the solder interconnect quality by means of drop impact testing, as standardized by e.g. JEDEC, during normal production requires considerable amounts of time and effort. Besides this, the repeatability of the drop impact test

J. J. M. Zaal; H. P. Hochstenbach; W. D. van Driel; G. Q. Zhang

2008-01-01

217

Gas-Actuated Projectile Launcher for High-Energy Impact Testing of Structures.  

National Technical Information Service (NTIS)

A gas-actuated penetration device has been developed for high-energy impact testing of structures. The high-energy impact testing is for experimental simulation of uncontained engine failures. The non-linear transient finite element, code LS-DYNASD has be...

D. R. Ambur N. Jaunky R. E. Lawson N. F. Knight K. H. Lyle

1999-01-01

218

Analysis and simulation of hypervelocity gouging impacts for a high speed sled test  

Microsoft Academic Search

An analysis and simulation of the gouging impact phenomenon which occurs at the Holloman Air Force Base High Speed Test Track (HHSTT) during hypervelocity impact testing is presented. Simulations of the sled\\/rail interactions were conducted using the hydrocode, CTH. These simulations utilize the most accurate and validated material models for the sled shoes (VascoMax 300) and rail (1080 steel) –

John D. Cinnamon; Anthony N. Palazotto

2009-01-01

219

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

PubMed

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. PMID:21512902

Irwin, Annette L; Mertz, Harold J

2010-11-01

220

The Effectiveness of the Component Impact Test Method for the Side Impact Injury Assessment of the Door Trim  

NASA Astrophysics Data System (ADS)

The complete evaluation of the side vehicle structure and the occupant protection is only possible by means of the full scale side impact crash test. But, auto part manufacturers such as door trim makers can not conduct the test especially when the vehicle is under the developing process. The main objective of this study is to obtain the design guidelines by a simple component level impact test. The relationship between the target absorption energy and impactor speed were examined using the energy absorbed by the door trim. Since each different vehicle type required different energy levels on the door trim. A simple impact test method was developed to estimate abdominal injury by measuring reaction force of the impactor. The reaction force will be converted to a certain level of the energy by the proposed formula. The target of absorption energy for door trim only and the impact speed of simple impactor are derived theoretically based on the conservation of energy. With calculated speed of dummy and the effective mass of abdomen, the energy allocated in the abdomen area of door trim was calculated. The impactor speed can be calculated based on the equivalent energy of door trim absorbed during the full crash test. With the proposed design procedure for the door trim by a simple impact test method was demonstrated to evaluate the abdominal injury. This paper describes a study that was conducted to determine sensitivity of several design factors for reducing abdominal injury values using the matrix of orthogonal array method. In conclusion, with theoretical considerations and empirical test data, the main objective, standardization of door trim design using the simple impact test method was established.

Youn, Younghan; Koo, Jeong-Seo

221

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

222

The Impact of State-Wide Numeracy Testing on the Teaching of Mathematics in Primary Schools  

ERIC Educational Resources Information Center

This paper reports on teachers' views of the effects of compulsory numeracy testing in Years 3, 5, and 7 in Queensland schools. Teachers were surveyed on (i) the validity and worth of the tests, (ii) the impact the tests had on their teaching of mathematics, and (iii) how they were using the results of the tests. Although the results reveal a…

Nisbet, Steven

2004-01-01

223

Water Impact Test and Simulation of a Composite Energy Absorbing Fuselage Section  

Microsoft Academic Search

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

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

2005-01-01

224

Bird Impact Qualification Test for A-10 Windshield.  

National Technical Information Service (NTIS)

One shot was made on the A-10's left side windshield for this program. The objective of this shot was to qualify the windshield. The shot was at a nominal velocity of 360 knots using a 4-lb bird. Descriptions of the test facility, test articles, and test ...

T. L. Buchanan

1987-01-01

225

The Impact of Gender in Oral Proficiency Testing.  

ERIC Educational Resources Information Center

Discusses the role of gender in speaking tests and suggests that in oral interviews it is possible that both interviewing and rating may be highly gendered processes. Audiotaped female and male test-takers who undertook practice IELTS interviews, one with a female interviewer and once with a male interviewer. Results from discourse and test score…

O'Loughlin, Kieran

2002-01-01

226

Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test  

Microsoft Academic Search

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

J. W. Forbes; C. M. Tarver; S. K. Chidester; F. Garcia; D. W. Greenwood; R. Garza

2000-01-01

227

ROTARY WING AIRCRAFT WATER IMPACT TEST AND ANALYSES CORRELATION  

Microsoft Academic Search

The Naval Air Warfare Center, Aircraft Division (NAWCAD) in cooperation with the Federal Aviation Administration (FAA) is sponsoring a Small Business Innovation Research (SBIR) Phase II program to investigate water impact dynamics relevant to DOD, DOT and industry. One of the primary objectives of the program is to develop analytical tools that can be used to facilitate the process of

Gil Wittlin; Mike Schultz; Michael R. Smith; Bell Helicopter

2000-01-01

228

Impact as a general cause of extinction: A feasibility test  

NASA Technical Reports Server (NTRS)

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.

Raup, David M.

1988-01-01

229

Development and Test of Fiberglass Low-Impact Resistant Towers.  

National Technical Information Service (NTIS)

A break-away fiberglass mast for use in low impact resistant (LIR) structures to support airport approach lighting systems has been developed. This design will withstand 100 mph winds (including gusts) without ice and 75 mph winds (including gusts) with a...

E. T. Rogers J. A. Ross K. M. Snyder

1979-01-01

230

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

NASA Technical Reports Server (NTRS)

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 tests and the material models developed in this program will be published in separate reports.

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

2013-01-01

231

Numerical Simulation of Viscoelastic Effects on the Rod Deformation of Taylor Impact Test  

NASA Astrophysics Data System (ADS)

In this study we analyzed the deformation of the polymeric rod impacting on the rigid wall which is called "Taylor impact test."" We simulated three-dimensional Taylor impact test depending on the various polymeric materials using the explicit finite element method by employing DYNA3D code. In simulation, polymeric materials were modeled using viscoelastic constitutive relations with the relaxation time and shear modulus. We have carried out the numerical simulation for the transient deformation characteristics and discussed effects of the viscoelastic constants on the deformation of the polymeric rod under impact.

Kim, See Jo; Lim, Kyung Hun; Shin, Hyung-Seop; Kim, Jeong-Tae; Choi, Joon Hong

232

Impact resistance of current design composite fan blades tested under short-haul operating conditions  

NASA Technical Reports Server (NTRS)

Boron/epoxy and graphite/epoxy composite blades were impacted in a rotating whirligig facility with conditions closely simulating those which might be experienced by a STOL engine impacted with various foreign objects. The tip speed of the rotating blades was 800 feet per second. The blades were impacted with simulated birds, real birds, ice balls, and gravel. The results of composite blade impact tests were compared with a titanium blade tested under similar conditions. Neither composite material indicated a clear superiority over the other. Blades made from both composite materials showed more damage than the titanium blades.

Steinhagen, C. A.; Salemme, C. T.

1973-01-01

233

Satellite Test of Radiation Impact on Ramtron 512K FRAM  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

234

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

NASA Technical Reports Server (NTRS)

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.

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

2013-01-01

235

Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864  

NASA Astrophysics Data System (ADS)

Two large heats of V-4Cr-4Ti alloy were produced in the US in the past few years. The first, 832665, was a 500 kg heat procured by the US Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800°C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000°C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750°C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent - no brittle failures at temperatures above -150°C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented (H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 30th June 1998, DOE/ER-0313/24, p. 3; H. Tsai, et al., Fusion Materials Semiannual Progress Report for Period Ending 31st December 1998, DOE/ER-0313/25, p. 3).

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

2000-12-01

236

Impact of Inclusion or Exclusion of Repeaters on Test Equating  

ERIC Educational Resources Information Center

This study examined the effect of including or excluding repeaters on the equating process and results. New forms of two tests were equated to their respective old forms using either all examinees or only the first timer examinees in the new form sample. Results showed that for both tests used in this study, including or excluding repeaters in the…

Puhan, Gautam

2011-01-01

237

Water impact laboratory and flight test results for the space shuttle solid rocket booster aft skirt  

NASA Technical Reports Server (NTRS)

A series of water impact tests was conducted using full-scale segment representations of the Space Shuttle Solid Rocket Booster (SRB) aft skirt structure. The baseline reinforced structural design was tested as well as various alternative design concepts. A major portion of the test program consisted of evaluating foam as a load attenuation material. Applied pressures and response strains were measured for impact velocities from 40 feet per second (ft/s) to 110 ft/s. The structural configurations, test articles, test results, and flight results are described.

Kross, D. A.; Murphy, N. C.; Rawls, E. A.

1984-01-01

238

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

NASA Technical Reports Server (NTRS)

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.

Nettles, A. T.

2001-01-01

239

Paleomagnetism of impact spherules from Lonar crater, India and a test for impact-generated fields  

NASA Astrophysics Data System (ADS)

Planetary surfaces have been ubiquitously melted by meteoroid impacts throughout solar system history. The resulting impact melts form some of the youngest igneous samples from rocky bodies like the Moon, Mars, and asteroids. Upon cooling, these melts may record any ambient planetary magnetic fields as well as postulated transient fields generated by impact plasmas. Impact-generated fields have been proposed as a key alternative to the core dynamo hypothesis for the paleomagnetism of extraterrestrial bodies. Here we describe a paleomagnetic study of basaltic impact glasses from the Lonar impact crater situated in the Deccan Traps in Maharashtra, India. Previous theoretical work predicts extremely strong magnetic fields (possibly >1,000 times the Earth's surface field) may have been transiently generated during the Lonar impact. We find that the glasses contain a natural remanent magnetization (NRM) whose properties depend strikingly on sample mass. Small (<0.5 g), splash-form samples demagnetize erratically and are inefficiently magnetized, while larger, irregularly shaped samples contain a stable component that is efficiently magnetized similar to Lonar basalts. However, the rock magnetic recording properties of these samples are uncorrelated with mass. Therefore, we conclude that the size dependence of the NRM reflects a difference in how the samples acquired thermoremanence. The splash forms of the smaller samples indicate they cooled during flight and therefore that they were magnetized while in motion, explaining their weak and unstable NRM. This motional NRM is a new manifestation of thermoremanent magnetization not observed before in geologic samples. No glasses contain evidence for any strong (>~100 ?T) impact-generated fields.

Weiss, Benjamin P.; Pedersen, Shelsea; Garrick-Bethell, Ian; Stewart, Sarah T.; Louzada, Karin L.; Maloof, Adam C.; Swanson-Hysell, Nicholas L.

2010-09-01

240

Measurement of Low Level Explosives Reaction in Gauged Multi-dimensional Steven Impact Tests  

NASA Astrophysics Data System (ADS)

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 mus 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.

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

2002-07-01

241

The Impact of Variability of Item Parameter Estimators on Test Information Function  

ERIC Educational Resources Information Center

The impact of uncertainty about item parameters on test information functions is investigated. The information function of a test is one of the most important tools in item response theory (IRT). Inaccuracy in the estimation of test information can have substantial consequences on data analyses based on IRT. In this article, the major part (called…

Zhang, Jinming

2012-01-01

242

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

NASA Technical Reports Server (NTRS)

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.

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

1977-01-01

243

Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test  

Microsoft Academic Search

The two-dimensional Steven impact test has been developed to be reproducible and amenable to computer modeling. Experiments were performed where explosives were impacted at levels below shock initiation levels. Carbon foil and carbon resistor pressure gauges were used. The carbon resistor gauges indicate a late time low level reaction at 300-400 mus after impact for inputs of 2-6 kb peak

J. W. Forbes; F. Garcia; D. W. Greenwood; R. G. Garza; C. M. Tarver; S. K. Chidester

1999-01-01

244

The impact of prepregnancy obesity on children's cognitive test scores.  

PubMed

To examine the association between maternal prepregnancy obesity and cognitive test scores of children at early primary school age. A descriptive observational design was used. Study subjects consist of 3,412 US children aged 60-83 months from the National Longitudinal Survey of Youth 1979 Mother and Child Survey. Cognitive test scores using the Peabody Individual Achievement Test reading recognition and mathematics tests were used as the outcomes of interest. Association with maternal prepregnancy obesity was examined using the ordinary least square regression controlling for intrauterine, family background, maternal and child factors. Children of obese women had 3 points (0.23 SD units) lower peabody individual achievement test (PIAT) reading recognition score (p = 0.007), and 2 points (0.16 SD units) lower PIAT mathematics scores (p < 0.0001), holding all other factors constant. As expected, cognitive test score was associated with stimulating home environment (reading: ? = 0.15, p < 0.0001, and math: ? = 0.15, p < 0.0001), household income (reading: ? = 0.03, p = 0.02 and math: ? = 0.04, p = 0.004), maternal education (reading: ? = 0.42, p = 0.0005, and math: ? = 0.32, p = 0.008), and maternal cognitive skills (reading: ? = 0.11, p < 0.0001, and math: ? = 0.09, p < 0.0001). There was a significant association between maternal prepregnancy obesity and child cognitive test scores that could not be explained by other intrauterine, family background, maternal, and child factors. Children who live in disadvantaged postnatal environments may be most affected by the effects of maternal prepregnancy obesity. Replications of the current study using different cohorts are warranted to confirm the association between maternal prepregnancy obesity and child cognitive test scores. PMID:22350633

Tanda, Rika; Salsberry, Pamela J; Reagan, Patricia B; Fang, Muriel Z

2013-02-01

245

The translational research impact scale: development, construct validity, and reliability testing.  

PubMed

Increasing emphasis is being placed on measuring return on research investment and determining the true impacts of biomedical research for medical practice and population health. This article describes initial progress on development of a new standardized tool for identifying and measuring impacts across research sites. The Translational Research Impact Scale (TRIS) is intended to provide a systematic approach to assessing impact levels using a set of 72 impact indicators organized into three broad research impact domains and nine subdomains. A validation process was conducted with input from a panel of 31 experts in translational research, who met to define and standardize the measurement of research impacts using the TRIS. Testing was performed to estimate the reliability of the experts' ratings. The reliability was found to be high (ranging from .75 to .94) in all of the domains and most of the subdomains. A weighting process was performed assigning item weights to the individual indicators, so that composite scores can be derived. PMID:24085789

Dembe, Allard E; Lynch, Michele S; Gugiu, P Cristian; Jackson, Rebecca D

2014-03-01

246

Prognostic impact of stress testing in coronary artery disease  

SciTech Connect

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.

Severi, S.; Michelassi, C. (CNR Clinical Physiology Institute, Pisa, (Italy))

1991-05-01

247

Passenger Rail Two-Car Impact Test Volume 1: Overview and Selected Results.  

National Technical Information Service (NTIS)

A full-scale, two-car impact test was conducted on April 4, 2000. Two coupled rail passenger cars impacted a fixed barrier at 26 mph. The cars were instrumented with strain gauges, accelerometers, and string potentiometers to measure the deformation of cr...

D. Tyrell K. Severson J. Zolock A. B. Perlman

2002-01-01

248

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

National Technical Information Service (NTIS)

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...

C. R. Ruggeri D. J. Altobelli D. M. Revilock J. M. Pereira W. C. Emmerling

2012-01-01

249

Analysis of Accelerations Measured during Full-Scale Tank Car Impact Tests.  

National Technical Information Service (NTIS)

Tank car impact responses were investigated using accelerometers mounted at various locations on a tank car. Several tests were run with both a full and an empty tank car, and varying the tank car impact speed. The data from the accelerometers went throug...

K. W. Koch M. L. Lyons W. T. Riddell

2007-01-01

250

A tensile testing technique for fibre-reinforced composites at impact rates of strain  

Microsoft Academic Search

A brief review is given of techniques which have been employed in attempts to determine the mechanical properties of composite materials under tensile impact loading. The difficulties encountered in the design of a satisfactory tensile impact testing machine for composite materials are discussed and a new method, using a modified version of the standard tensile split Hopkinson's pressure bar (SHPB),

J. Harding; L. M. Welsh

1983-01-01

251

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

ERIC Educational Resources Information Center

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…

Schochet, Peter Z.

2008-01-01

252

The impact of prepregnancy obesity on children's cognitive test scores  

PubMed Central

Objective To examine the association between maternal prepregnancy obesity and cognitive test scores of children at early primary school age. Methods A descriptive observational design was used. Study subjects consist of 3412 US children aged 60 to 83 months from the National Longitudinal Survey of Youth 1979 Mother and Child Survey. Cognitive test scores using the Peabody Individual Achievement Test reading recognition and mathematics tests were used as the outcomes of interest. Association with maternal prepregnancy obesity was examined using the ordinary least square regression controlling for intrauterine, family background, maternal and child factors. Results Children of obese women had 3 points (0.23 SD units) lower PIAT reading recognition score (p=0.007), and 2 points (0.16 SD units) lower PIAT mathematics scores (p<.0001), holding all other factors constant. As expected, cognitive test score was associated with stimulating home environment (reading: ?=0.15, p<.0001, and math: ?=0.15, p<.0001), household income (reading: ?=0.03, p=0.02 and math: ?=0.04, p=0.004), maternal education (reading: ?=0.42, p=0.0005, and math: ?=0.32, p=0.008), and maternal cognitive skills (reading: ?=0.11, p<.0001, and math: ?=0.09, p<.0001). Conclusion There was a significant association between maternal prepregnancy obesity and child cognitive test scores that could not be explained by other intrauterine, family background, maternal, and child factors. Children who live in disadvantaged postnatal environments may be most affected by the effects of maternal prepregnancy obesity. Replications of the current study using different cohorts are warranted to confirm the association between maternal prepregnancy obesity and child cognitive test scores.

Tanda, Rika; Salsberry, Pamela J.; Reagan, Patricia B.; Fang, Muriel Z.

2012-01-01

253

Experimental and Modeling Studies of Crush, Puncture, and Perforation Scenarios in the Steven Impact Test.  

National Technical Information Service (NTIS)

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 stud...

K. S. Vandersall S. K. Chidester J. W. Forbes F. Garcia

2002-01-01

254

Vehicle Barrier Impact Testing with Hybrid III Dummies in a 1987 Ford Escort 5-Door Hatchback.  

National Technical Information Service (NTIS)

A 30 mph flat frontal barrier impact test was conducted on a 1987 Ford Escort 5-door hatchback at the Transportation Research Center of Ohio on December 16, 1987, using Hybrid III driver and passenger dummies.

J. W. Sankey

1988-01-01

255

Vehicle Barrier Impact Testing with Hybrid III Dummies in a 1987 Toyota Camry 4-Door Sedan,  

National Technical Information Service (NTIS)

A 30 mph flat frontal barrier impact test was conducted on a 1987 Toyota Camry 4-door sedan at the Transportation Research Center of Ohio on November 3, 1987, using Hybrid III driver and passenger dummies.

J. W. Sankey

1987-01-01

256

The evolution and impact of testing baghouse filter performance.  

PubMed

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. PMID:22916439

Pham, Minh; Clark, Christina; Mckenna, John

2012-08-01

257

Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test  

Microsoft Academic Search

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.

L. L. Switzer; K. S. Vandersall; S. K. Chidester; D. W. Greenwood; C. M. Tarver

2003-01-01

258

Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test  

Microsoft Academic Search

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

Lori L. Switzer; Kevin S. Vandersall; Steven K. Chidester; Daniel W. Greenwood; Craig M. Tarver

2004-01-01

259

Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test  

Microsoft Academic Search

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

Lori L. Switzer; Kevin S. Vandersall; Steven K. Chidester; Daniel W. Greenwood; Craig M. Tarver

2004-01-01

260

Particle Impact Ignition Test Data on a Stainless Steel Hand Valve  

NASA Technical Reports Server (NTRS)

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.

Peralta, Stephen

2010-01-01

261

DESIGN AND SET-UP OF A BI-PENDULUM IMPACT TESTING MACHINE  

Microsoft Academic Search

In this work the design and set-up of a bi-pendulum testing rig able to perform low-velocity impact measurements on small and medium-size components is reported. Experimental tests were conducted both to check the theoretically calculated value of the equivalent impacting mass and to quantify the overall energy losses during the idle movement of the mass. In order to provide useful

Leonardo D'Acquisto; Roberto Montanini

262

The influence of a flexible lumbar spine in far-side impact testing  

Microsoft Academic Search

Recent findings have shown the nearside impact dummies BioSID and EuroSID to be less applicable in far-side testing. In this paper, the lumbar spine of a BioSID dummy was replaced with a coil spring to enable a more extensive shearing, bending and elongation of the dummy spine. Using a sled test method developed to replicate a 65-km\\/h impact full-scale far-side

B. Fildes; O. Bostrom; L. Sparke; F. Pintar; N. Yoganandan

2006-01-01

263

The Evolution and Impact of Testing Baghouse Filter Performance  

Microsoft Academic Search

In 1995, the United States 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

P. E. Minh Pham; Christina Clark; John McKenna

2012-01-01

264

SRB/FWC water impact: Flexible body loads test  

NASA Technical Reports Server (NTRS)

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.

1984-01-01

265

The Impact of Inflation Targeting: Testing the Good Luck Hypothesis  

Microsoft Academic Search

Over the last twenty years the level and volatility of inflation decreased across industrial countries. The inflation behaviour can be explained by a shift in monetary policy or by a lucky period of low volatility in business cycle shocks. To test the 'luck hypothesis' we examine the inflation experience of Canada, one of the earliest and most successful adopters of

Federico Ravenna

2008-01-01

266

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

NASA Technical Reports Server (NTRS)

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.

Engle, Carl; Herald, Stephen; Watkins, Casey

2005-01-01

267

HE friction sensitivity. Oblique impact sensitivity of explosives (the skid test). Quarterly report, April--June, 1971  

Microsoft Academic Search

Oblique impact tests were performed on both artificially aged and unaged LX-09-0. Oblique impact, instrumented vertical drops, and friction tests were performed on RX-25-AA. An extensive oblique impact and instrumented vertical drop test series was performed using three compositional variations of LX-10-0.

Velkinburgh; J. H. van

1971-01-01

268

Single and Multiple Impact Ignition of New and Aged High >>Explosives in the Steven Impact Test  

Microsoft Academic Search

The threshold velocities for several new and aged HMX-based high explosives have been measured using three different projectile designs. Multiple impacts of damaged but unreacted charges were fired at reduced velocities until those charges reacted. Blast overpressure and embedded pressure gauges were used to determine the relative violence of the explosive reactions. Ignition and Growth reactive flow computer modeling was

S. K. Chidester; C. M. Tarver; R G Garza

1999-01-01

269

Side Impact Sub-System Test Development: MVMA (Motor Vehicle Manufacturer's Association) Thoracic Impactor Test Procedure and Evaluation.  

National Technical Information Service (NTIS)

In the last several years, much attention has been devoted to the subject of side impact safety in passenger cars. During fiscal year 1985, the Motor Vehicle Manufacturer's Association (MVMA) sponsored the development of a thoracic sub-system test device ...

D. T. Willke M. W. Monk

1988-01-01

270

Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing  

PubMed Central

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.

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

2014-01-01

271

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

PubMed

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. PMID:24955400

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

2014-01-01

272

Impact of shock on pain reactivity: III. The magnitude of hypoalgesia observed depends on test location.  

PubMed

Pain reactivity is often assessed in rodents by measuring the latency of tail withdrawal from radiant heat (the tail-flick test). Using this test, the authors show that the magnitude of antinociception observed in spinal rats depends on test location; antinociception is observed at, and distal to, where shock is applied, but not at more proximal sites (Experiments 1 & 2). Experiment 3 evaluates the generality of this observation by testing 3 other shock schedules that are known to elicit distinct forms of antinociception. In all but 1 case, the magnitude of antinociception varied as a function of test location. Experiment 4 shows that morphine also has a greater impact at distal test locations. Experiment 5 assessed the impact of tailshock on reactivity to radiant heat applied to the foot. Of the 5 distinct forms of shock-induced antinociception studied, only 2 produce a robust antinociception at this test location. PMID:8888998

Prentice, T W; Joynes, R L; Meagher, M W; Grau, J W

1996-06-01

273

Impact testing of the H1224A shipping/storage container  

SciTech Connect

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.

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

1994-05-01

274

Single and Multiple Impact Ignition of New and Aged High >>Explosives in the Steven Impact Test  

NASA Astrophysics Data System (ADS)

The threshold velocities for several new and aged HMX-based high explosives have been measured using three different projectile designs. Multiple impacts of damaged but unreacted charges were fired at reduced velocities until those charges reacted. Blast overpressure and embedded pressure gauges were used to determine the relative violence of the explosive reactions. Ignition and Growth reactive flow computer modeling was used to predict the changes in threshold velocity and relative reaction violence produced by the different projectile shapes. These reactive flow models can then be used to predict impact hazard scenarios that can not be measured directly. (This work was performed under the auspices of the United States Department of Energy by the Lawrence Livermore National Laboratory under Contact No. W-7405-ENG-48.)

Chidester, S. K.; Tarver, C. M.

1999-06-01

275

Predicting ground level impacts of solid rocket motor testing  

NASA Technical Reports Server (NTRS)

Beginning in August of 1988 and continuing until the present, NASA at Stennis Space Center, Mississippi has conducted environmental monitoring of selected static test firings of the solid rocket motor used on the Space Shuttle. The purpose of the study was to assess the modeling protocol adapted for use in predicting plume behavior for the Advanced Solid Rocket Motor that is to be tested in Mississippi beginning in the mid-1990's. Both motors use an aluminum/ammonium perchlorate fuel that produces HCl and Al2O3 particulates as the major combustion products of concern. A combination of COMBUS.sr and PRISE.sr subroutines and the INPUFF model are used to predict the centerline stabilization height, the maximum concentration of HCl and Al2O3 at ground level, and distance to maximum concentration. Ground studies were conducted to evaluate the ability of the model to make these predictions. The modeling protocol was found to be conservative in the prediction of plume stabilization height and in the concentrations of the two emission products predicted.

Douglas, Willard L.; Eagan, Ellen E.; Kennedy, Carolyn D.; Mccaleb, Rebecca C.

1993-01-01

276

Contact and artificial soil tests using earthworms to evaluate the impact of wastes in soil  

SciTech Connect

The study was designed to evaluate two methods using earthworms that can be used to estimate the biological impact of organic and inorganic compounds that may be in wastes applied to land for treatment and disposal. The two methods were the contact test and the artificial soil test. The contact test is 48-h test using an adult worm, a small glass vial, and filter paper to which the test chemical or waste is applied. The test is designed to provide close contact between the worm and a chemical, similar to the situation in soils. The method provides a rapid estimate of the relative toxicity of chemicals and industrial wastes.

Neuhauser, E.F.; Loehr, R.C.; Malecki, M.R.

1986-01-01

277

Wheelchair impact response to ISO test pendulum and ISO standard curb  

Microsoft Academic Search

If a product is to be certified by a national or international organization, it must undergo and pass a series of standardized tests. Standards are required to establish minimum performance and durability criteria for wheelchairs. Standards benefit consumers, manufacturers, and third party providers. Testers have expressed concern over the difficulty of properly conducting the current impact test for wheelchair casters

Roy A. Cooper; Rick N. Robertson; David P. Vansickle; Ken J. Stewart; Steven J. Albright

1994-01-01

278

Rotor dynamic impact damper test results for synchronous and subsynchronous vibration  

Microsoft Academic Search

The design of an elevated-temperature impact damper and ambient rig test results are reported. Test results include subsynchronous and synchronous damping effectiveness as well as damper unbalance sensitivity for a rotor bounce and first two shaft bend modes. Changes in damper effectiveness with impactor geometry and construction are examined. Impactor orbital displacement plots are included to show how the relative

Tim A. Nale; Steven A. Klusman

1992-01-01

279

Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test  

Microsoft Academic Search

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

K S Vandersall; L L Switzer; F Garcia

2005-01-01

280

Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test.  

National Technical Information Service (NTIS)

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 attem...

K. S. Vandersall L. L. Switzer F. Garcia

2005-01-01

281

Analysis of Colliding Vehicle Interactions for the Passenger Rail Train-To-Train Impact Test.  

National Technical Information Service (NTIS)

A full-scale train-to-train impact test was performed in which a cab car-led passenger train traveling at 30 mph collided with a standing locomotive-led train. During the test, the lead cab car overrode the cab of the standing locomotive, sustaining appro...

P. Liana R. Rancatore R. Stringfellow

2004-01-01

282

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

Microsoft Academic Search

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 reflects the presence of

Wilfried De Corte; Filip Lievens

2005-01-01

283

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

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

284

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection  

NASA Technical Reports Server (NTRS)

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.

Barbee, Brent W.; Hernandez, Sonia

2012-01-01

285

Methods for testing theory and evaluating impact in randomized field trials  

PubMed Central

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.

Brown, C. Hendricks; Wang, Wei; Kellam, Sheppard G.; Muthen, 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

286

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

NASA Astrophysics Data System (ADS)

The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and 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 350 ms after projectile impact, creating 0.5-0.6 kb peak shocks centered in PBX 9501 explosives discs. Steven Test calculations based on ignition and growth criteria predict low level reactions occurring at 335 ms which agrees well with experimental data. Additional gauged experiments simulating the Steven Test have been performed and will be discussed. * 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.

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

2001-06-01

287

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

NASA Astrophysics Data System (ADS)

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.

Howell, Byron Edward

2001-12-01

288

The Impact of Test Outcome Certainty on Interest in Genetic Testing Among College Women  

Microsoft Academic Search

Osteoporosis and hemochromatosis are both late-onset preventable diseases, but future genetic tests for these conditions are likely to differ in their predictive abilities. To determine whether interest in a specific genetic test for hemochromatosis would be higher than interest in a theoretical test for osteoporosis susceptibility, undergraduate women at the University of Cincinnati (N = 181) were surveyed regarding their

Lisa M. Paglierani; Heidi J. Kalkwarf; Susan L. Rosenthal; Carl A. Huether; Richard J. Wenstrup

2003-01-01

289

The Geological impact of Nuclear Testing at the Nevada Test Site  

Microsoft Academic Search

The Nevada Test Site is an area designated by the United States Government for Nuclear Weapons testing. It is located in rural southern Nevada and is about the size of the State of Rhode Island. This location was founded in 1952 as one of 5 on land sites designated for this task. Above ground nuclear or atmospheric testing was conducted

Rachel Henderson

290

Impact Testing and Analysis of Composites for Aircraft Engine Fan Cases  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

291

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

NASA Technical Reports Server (NTRS)

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.

Lyons, Frankel

2013-01-01

292

Long-Term Test-Retest Reliability of Baseline Cognitive Assessments Using ImPACT  

Microsoft Academic Search

Background: Computer-based assessment programs are commonly used to document baseline cognitive performance for comparison with postconcussion testing. There are currently no guidelines for how often baseline assessments should be updated, and no data documenting the test-retest stability of baseline measures over relevant time periods.Purpose: To establish long-term test-retest reliability of baseline assessments using ImPACT, and to compare various statistical methods

Philip Schatz

2010-01-01

293

Influence of Belt Pretensioning on Dummy Responses in 40 km\\/h Rear Impact Sled Tests  

Microsoft Academic Search

Objective: This study compares dummy kinematics and biomechanical responses with and without belt pretensioning in matched rear sled tests.Methods: Two rear impact sled tests were run at 40 km\\/h (25 mph) rear delta V with a lap-shoulder belted Hybrid III 50 male dummy on Ford F-150 driver seats. One test was with the standard lap-shoulder belts and the other activated

David C. Viano; Chantal S. Parenteau; Roger Burnett

2011-01-01

294

Scaling numerical models for hypervelocity test sled slipper-rail impacts  

Microsoft Academic Search

Hypervelocity test sled slipper-rail impacts have been simulated numerically using the finite volume hydrocode, ChartD to the Three-Halves (CTH). This study addresses the difficulties of applying CTH model solutions to real test sled runs. Past CTH models using dimensions different than actual test sleds have been used to study phenomenological aspects of the problem. However, quantitative results from the CTH

A. G. Szmerekovsky; A. N. Palazotto; W. P. Baker

2006-01-01

295

Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test  

NASA Astrophysics Data System (ADS)

The two-dimensional Steven impact test has been developed to be reproducible and amenable to computer modeling. Experiments were performed where explosives were impacted at levels below shock initiation levels. Carbon foil and carbon resistor pressure gauges were used. The carbon resistor gauges indicate a late time low level reaction at 300-400 ?s after impact for inputs of 2-6 kb peak shocks at the center of explosive discs. Some experiments simulating the Steven impact test were done on a gas gun with carbon foil gauges in PMMA. Hydrodynamic calculations will be used to evaluate the gauge performance in these experiments. The long term goal is to develop two-dimensional shock diagnostic techniques that are more than just time of arrival indicators.

Forbes, J. W.; Garcia, F.; Greenwood, D. W.; Garza, R. G.; Tarver, C. M.; Chidester, S. K.

1999-06-01

296

Supplemental final environmental impact statement for advanced solid rocket motor testing at Stennis Space Center  

NASA Technical Reports Server (NTRS)

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.

1990-01-01

297

An impact excitation system for repeatable, high-bandwidth modal testing of miniature structures  

NASA Astrophysics Data System (ADS)

Miniature components and devices are increasingly seen in a myriad of applications. In general, the dynamic behavior of miniature devices is critical to their functionality and performance. However, modal testing of miniature structures poses many challenges. This paper presents a design and evaluation of an impact excitation system (IES) for repeatable, high-bandwidth, controlled-force modal testing of miniature structures. Furthermore, a dynamic model of the system is derived and experimentally validated to enable the identification of the system parameters that yield single-hit impacts with desired bandwidth and force magnitude. The system includes a small instrumented impact tip attached to a custom designed flexure-based body, an automated electromagnetic release mechanism, and various precision positioners. The excitation bandwidth and the impact force magnitude can be controlled by selecting the system parameters. The dynamic model of the system includes the structural dynamics of the flexure-based body, the electromagnetic force and the associated eddy-current damping, and the impact event. A validation study showed an excellent match between the model simulations and experiments in terms of impact force and bandwidth. The model is then used to create process maps that relate the system parameters to the number of hits (single vs. multiple), the impact force magnitudes and the excitation bandwidths. These process maps can be used to select system parameters or predict system response for a given set of parameters. A set of experiments is conducted to compare the performances of the IES and a (manual) miniature impact hammer. It is concluded that the IES significantly improves repeatability in terms of the impact bandwidth, location, and force magnitude, while providing a high excitation-bandwidth and excellent coherence values. The application of the IES is demonstrated through modal testing of a miniature contact-probe system.

Bediz, Bekir; Korkmaz, Emrullah; Burak Ozdoganlar, O.

2014-06-01

298

Deformation behavior of Inconel 690 super alloy evaluated by impact test  

Microsoft Academic Search

The dynamic impact deformation behavior, fracture characteristics and microstructural evolution of Inconel 690 alloy under high rate loading conditions are studied. Mechanical impact tests are performed at strain rates ranging from 2.3×103 to 8.3×103s?1 at room temperature by compressive split-Hopkinson bar. The effects of strain rate on dynamic flow response, work hardening characteristics, strain rate sensitivity and thermal activation volume

Woei-Shyan Lee; Chen-Yang Liu; Tai-Nong Sun

2004-01-01

299

Evaluate anti-shock property of solder bumps by impact test  

Microsoft Academic Search

Anti-shock property of lead-free Sn96.5-Ag3.0-Cu0.5 solder bumps was investigated by the high speed impact to explore the relation among the fracture modes and the reflow profile and the microstructure of solder joint. Solder bumps were formed with various reflow profiles and multi-reflow and then subjected to the impact test under a constant speed of 1.8 m\\/s and a shear standoff

Hongjia Xi; Minyi Lou; Bing An; Fengshun Wu; Yiping Wu

2008-01-01

300

Testing and numerical modeling of hypervelocity impact damaged Space Station multilayer insulation  

NASA Technical Reports Server (NTRS)

Results are presented of experiments measuring the degradation of the insulating capabilities of the multilayer insulation (MLI) of the Space Station Freedom, when subjected to hypervelocity impact damage. A simple numerical model was developed for use in an engineering design environment for quick assessment of thermal effect of the impact. The model was validated using results from thermal vacuum tests on MLI with simulated damage. The numerical model results agreed with experimental data.

Rule, William K.

1992-01-01

301

Investigation and comparison between new satellite impact test results and NASA standard breakup model  

Microsoft Academic Search

This paper summarizes two new satellite impact tests conducted in order to investigate on the outcome of low- and hypervelocity impacts on two identical target satellites. The first experiment was performed at a low velocity of 1.5km\\/s using a 40-g aluminum alloy sphere, whereas the second experiment was performed at a hypervelocity of 4.4km\\/s using a 4-g aluminum alloy sphere,

K. Sakuraba; Y. Tsuruda; T. Hanada; J.-C. Liou; Y. Akahoshi

2008-01-01

302

Investigation of Steven Impact Test Using a Transportation Hook Projectile with Gauged Experiments and 3D Modeling  

Microsoft Academic Search

The Steven Impact Test and associated modeling offer valuable practical predictions for evaluating numerous safety scenarios involving low velocity impact of energetic materials by different projectile geometries. One such scenario is the impact of energetic material by a transportation hook during shipping, which offers complexity because of the irregular hook projectile shape. Experiments were performed using gauged Steven Test targets

Kevin S. Vandersall; Susarla S. Murty; Steven K. Chidester; Jerry W. Forbes; Frank Garcia; Daniel W. Greenwood; Craig M. Tarver

2004-01-01

303

Investigation of Steven Impact Test Using a Transportation Hook Projectile with Gauged Experiments and 3D Modeling  

Microsoft Academic Search

The Steven Impact Test and associated modeling offer valuable practical predictions for evaluating numerous safety scenarios involving low velocity impact of energetic materials by different projectile geometries. One such scenario is the impact of energetic material by a transportation hook during shipping, which offers complexity because of the irregular hook projectile shape. Experiments were performed using gauged Steven Test targets

K S Vandersall; S S Murty; S K Chidester; J W Forbes; F Garcia; D W Greenwood; C M Tarver

2003-01-01

304

Ceramic nuclear fuel mechanical resistance development by means of dynamic impact testing.  

PubMed

In commercial reactors where a 'pellet missing surface' is observed a cladding crack has also been observed several times. Chips are produced mainly by dynamic impacts during pellet production process as a whole, i.e. emptying the sintering boats, pellets handling, vibration in the bowl feeder and grinding. At this work UO(2) chipping behavior was investigated and showed that pellets with higher density resist more to impacts and also that at the lowest impact angle tested the pellet weight loss was quite high. PMID:21190863

Santana, H H S; Maier, G; Ródenas, J

2011-08-01

305

Comparison of Hybrid III child test dummies to pediatric PMHS in blunt thoracic impact response.  

PubMed

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. PMID:20730687

Parent, D P; Crandall, J R; Bolton, J R; Bass, C R; Ouyang, J; Lau, S H

2010-08-01

306

Mechanical impact tests of materials in oxygen effects of contamination. [Teflon, stainless steel, and aluminum  

NASA Technical Reports Server (NTRS)

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.

Ordin, P. M.

1980-01-01

307

Prediction of a Modified Ptw Model for Various Taylor Impact Tests of Tantalum  

NASA Astrophysics Data System (ADS)

The strain hardening part of the Preston-Tonks-Wallace (PTW) model, developed for the description of the plastic constitutive behavior of materials at wide ranges of strain, strain rate, and temperature, has been modified by employing the Voce equation. The prediction capability of the modified PTW (MPTW) has been investigated with reference to Taylor impact test results in the literature, and comparison has been made with the models of Johnson-Cook (JC), Steiberg-Guinan (SG), Zerilli-Armstrong (ZA), and PTW. Of the compared existing models, no model was appropriate for describing the results of various Taylor impact tests. However, the modified PTW is shown to predict fairly accurate results in terms of the length, diameter, and shape of the deformed specimen tested at different temperatures and impact velocity.

Kim, Jong-Bong; Shin, Hyunho

308

Guidelines for conducting impact tests on shipping packages for radioactive material  

SciTech Connect

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.

Mok, G.C.; Carlson, R.W.; Lu, S.C.; Fischer, L.E.

1995-09-01

309

Social and psychological impact of HPV testing in cervical screening: a qualitative study  

PubMed Central

Objective Human papillomavirus (HPV) testing has been proposed for inclusion in the UK cervical screening programme. While testing may bring some benefits to the screening programme, testing positive for HPV, a sexually transmitted virus, may have adverse social and psychological consequences for women. The aim of this study was to examine the social and psychological impact of HPV testing in the context of cervical cancer screening. Method In?depth interviews generating qualitative data were carried out with 74 women participating in HPV testing in England between June 2001 and December 2003. Purposive sampling was used to ensure heterogeneity in age, ethnic group, marital status, socioeconomic background, cytology, and HPV results among participants. Results Testing positive for HPV was associated with adverse social and psychological consequences, relating primarily to the sexually transmitted nature of the virus and its link to cervical cancer. Women described feeling stigmatised, anxious and stressed, concerned about their sexual relationships, and were worried about disclosing their result to others. Anxiety about the infection was widespread, but the impact of testing positive varied. The psychological burden of the infection related to women's relationship status and history, their social and cultural norms and practices around sex and relationships, and their understanding of key features of HPV. Conclusion HPV testing should be accompanied by extensive health education to inform women and to de?stigmatise infection with the virus to ensure that any adverse impact of the infection on women's wellbeing is minimised.

McCaffery, K; Waller, J; Nazroo, J; Wardle, J

2006-01-01

310

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

Microsoft Academic Search

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°); lower tests have not been performed yet. {open_quotes}Reduced-H.E.{close_quotes} pieces of PBX 9404,

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

1997-01-01

311

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4  

NASA Technical Reports Server (NTRS)

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.

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

312

Quasi-Uniform High Speed Foam Crush Testing Using a Guided Drop Mass Impact  

NASA Technical Reports Server (NTRS)

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.

Jones, Lisa E. (Technical Monitor); Kellas, Sotiris

2004-01-01

313

Characterization of knee-thigh-hip response in frontal impacts using biomechanical testing and computational simulations.  

PubMed

Development and validation of crash test dummies and computational models that are capable of predicting the risk of injury to all parts of the knee-thigh-hip (KTH) complex in frontal impact requires knowledge of the force transmitted from the knee to the hip under knee impact loading. To provide this information, the knee impact responses of whole and segmented cadavers were measured over a wide range of knee loading conditions. These data were used to develop and help validate a computational model, which was used to estimate force transmitted to the cadaver hip. Approximately 250 tests were conducted using five unembalmed midsize male cadavers. In these tests, the knees were symmetrically impacted with a 255-kg padded impactor using three combinations of knee-impactor padding and velocity that spanned the range of knee loading conditions produced in FMVSS 208 and NCAP tests. Each subject was tested in four conditions. Following test of whole seated cadavers, the subjects were impacted after the connection between the thigh flesh and pelvis was cut, after the thigh flesh was removed, and after the torso was removed. Applied force and femur and pelvis acceleration data from these tests and results of other studies were used with data on static body segment masses to develop and validate a one-dimensional lumped-parameter model of the body. Simulation of the whole body cadaver tests performed with this model predict that approximately 54% of the peak force applied to the knee was transmitted to the hip for all three impact velocities. Additional simulations with the model in which knee impact conditions were varied over a wider range of loading conditions indicate that the percentage drop in force between the knee and the hip is relatively constant over the range of knee impact conditions that are of interest for injury assessment. Simulation results also indicate that high-rate, short-duration knee loading by a rigid surface is more likely to produce knee/distal femur fractures and less likely to produce hip fractures due to laxity in the hip that delays recruitment of pelvis mass and the development of fracture-level forces at the hip until after the fracture tolerance of the knee/femur has been exceeded. PMID:19085172

Rupp, Jonathan D; Miller, Carl S; Reed, Matthew P; Madura, Nathaniel H; Klinich, Kathleen D; Schneider, Lawrence W

2008-11-01

314

Dynamic Testing for Side Crush MRB-to-Car Side Impact Test of a 90 deg Moving Rigid Barrier to a 1983 Ford Escort: Test No. 1, 16.1 mph, Test No. 2, 32.2 mph.  

National Technical Information Service (NTIS)

The test report documents two of a series of nine crash tests to measure side crush in various vehicle models. Testing was conducted on a 1983 Ford Escort 2-door Hatchback. The test vehicle was impacted on the left and right side perpendicular by a Moving...

N. A. El-Habash

1986-01-01

315

Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program.  

National Technical Information Service (NTIS)

This document contains the analysis details and summary of analyses conducted to evaluate the environmental impacts for the Resumption of Transient Fuel and Materials Testing Program. It provides an assessment of the impacts for the two action alternative...

2013-01-01

316

A unified theory of impact crises and mass extinctions: quantitative tests.  

PubMed

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, and gradual ecological recovery and radiation of new taxa. Isotopic and other geochemical signatures are also generally consistent with the expected after-effects of catastrophic impacts. Seven of the recognized extinction pulses seem to be associated with concurrent (in some cases multiple) stratigraphic impact markers (e.g., layers with high iridium, shocked minerals, microtektites), and/or large, dated impact craters. Other less well-studied crisis intervals show elevated iridium, but well below that of the K/T spike, which might be explained by low-Ir impactors, ejecta blowoff, or sedimentary reworking and dilution of impact signatures. The best explanation for a possible periodic component of approximately 30 Myr in mass extinctions and clusters of impacts is the pulselike modulation of the comet flux associated with the solar system's periodic passage through the plane of the Milky Way Galaxy. The quantitative agreement between paleontologic and astronomical data suggests an important underlying unification of the processes involved. PMID:11543121

Rampino, M R; Haggerty, B M; Pagano, T C

1997-05-30

317

HE friction sensitivity oblique impact sensitivity of explosives (the SKID test). Progress report, October 1971December 1971  

Microsoft Academic Search

The oblique impact test series on LX-10-0 Lot 710-2 was completed. Two instrumented oblique impact tests were done using RX-04-DW dropped at 45°, 5Ⲡon a smooth steel surface. One additional oblique impact using RX-04-EB at 45° 3.5Ⲡwas done. An instrumented vertical drop and oblique impact series was begun on RX-04-EC (96\\/4 HMX\\/Viton).

Van Velkinburgh

1998-01-01

318

1 year test-retest reliability of ImPACT in professional ice hockey players.  

PubMed

The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery is widely used to assess neurocognitive outcomes following sports-related concussion. The purpose of this study was to examine the 1 year test-retest reliability of ImPACT in a multilingual sample of professional hockey players. A total of 305 professional hockey players were tested 1 year apart using ImPACT. Reliable change confidence intervals were calculated and test-retest reliability was measured using Pearson and Intraclass correlation coefficients. Results indicated that the 1-year test-retest reliabilities for the Visual Motor and Reaction Time Composites ranged from low to high (.52 to .81). In contrast, 1-year test-retest reliabilities for the Verbal and Visual Memory Composites were low (.22 to .58). The 1-year test-retest results provided mixed support for the use of Visual Motor and Reaction Time Composites in select samples; in contrast, the Verbal and Visual Memory Composites may not be sensitive to clinical change. PMID:24345194

Bruce, Jared; Echemendia, Ruben; Meeuwisse, Willem; Comper, Paul; Sisco, Amber

2014-01-01

319

A Comparison of Quasi-Static Indentation and Drop-Weight Impact Testing on Carbon/Epoxy Laminates  

NASA Technical Reports Server (NTRS)

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.

Prabhakaran, R.; Douglas, Michael J.

2000-01-01

320

Impact Foam Testing for Multi-Mission Earth Entry Vehicle Applications  

NASA Technical Reports Server (NTRS)

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.

Glaab, Louis J.; Agrawal, Paul; Hawbaker, James

2013-01-01

321

Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model  

NASA Technical Reports Server (NTRS)

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.

Sakuraba, K.; Tsuruda, Y.; Hanada, T.; Liou, J.-C.; Akahoshi, Y.

2007-01-01

322

Ensayo de Corrosion de Mallas en Laminados de Fibra de Carbono Probetas de Impacto al Rayo (Corrosion Tests of Meshes in Carbon Fiber Laminates: Impact Beam Tests).  

National Technical Information Service (NTIS)

Corrosion resistance test results of copper alloy metal meshes, used in beam impact tests, are summarized. The use of a painting system is advised to avoid corrosion appearance in the metal meshes during an aircraft's service lifetime.

1990-01-01

323

Integrated assessment of pedestrian head impact protection in testing secondary safety and autonomous emergency braking.  

PubMed

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. PMID:24246294

Searson, D J; Anderson, R W G; Hutchinson, T P

2014-02-01

324

Impact Test and Simulation of Energy Absorbing Concepts for Earth Entry Vehicles  

NASA Technical Reports Server (NTRS)

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.

Billings, Marcus D.; Fasanella, Edwin L.; Kellas, Sotiris

2001-01-01

325

HIV Testing in Correctional Agencies and Community Treatment Programs: The Impact of Internal Organizational Structure  

PubMed Central

This study compares the provision of HIV testing in a nationally representative sample of correctional agencies and community-based substance abuse treatment programs and identifies the internal organizational-level correlates of HIV testing in both organizations. Data are derived from the CJ-DATS’ National Criminal Justice Treatment Practices Survey (NCJTP). Using an organizational diffusion theoretical framework (Rogers, 2003), the impact of Centralization of Power, Complexity, Formalization, Interconnectedness, Organizational Resources, and Organizational Size on HIV testing was examined in correctional agencies and treatment programs. While there were no significant differences in the provision of HIV testing among correctional agencies (49%) and treatment programs (50%), the internal organizational-level correlates were more predictive of HIV testing in correctional agencies. Specifically, all dimensions, with the exception of Formalization, were related to the provision of HIV testing in correctional agencies. Implications for correctional agencies and community treatment to adopt HIV testing are discussed.

Oser, Carrie B.; Tindall, Michele Staton; Leukefeld, Carl G.

2007-01-01

326

LX04 Violence Measurements-Steven Tests Impacted by Projectiles Shot from a Howitzer Gun  

Microsoft Academic Search

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,

Steven K. Chidester; Kevin S. Vandersall; Lori L. Switzer; Craig M. Tarver

2006-01-01

327

LX04 Violence Measurments: Steven Tests Impacted By Projectiles Shot From A Howitzer Gun  

Microsoft Academic Search

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

Steven K. Chidester

2005-01-01

328

LX04 Violence Measurements-Steven Tests Impacted by Projectiles Shot from a Howitzer Gun  

Microsoft Academic Search

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,

Steven K. Chidester; Kevin S. Vandersall; Lori L. Switzer; Craig M. Tarver

2006-01-01

329

Statistical variations in impact resistance of steel fiber-reinforced concrete subjected to drop weight test  

Microsoft Academic Search

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

M. C. Nataraja; N. Dhang; A. P. Gupta

1999-01-01

330

A small-scale test for fiber release from carbon composites. [pyrolysis and impact  

NASA Technical Reports Server (NTRS)

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.

Gilwee, W. J., Jr.; Fish, R. H.

1980-01-01

331

Pharmacogenetics and population pharmacokinetics: impact of the design on three tests using the SAEM algorithm  

Microsoft Academic Search

Pharmacogenetics is now widely investigated and health institutions acknowledge its place in clinical pharmacokinetics. Our\\u000a objective is to assess through a simulation study, the impact of design on the statistical performances of three different\\u000a tests used for analysis of pharmacogenetic information with nonlinear mixed effects models: (i) an ANOVA to test the relationship\\u000a between the empirical Bayes estimates of the

Julie Bertrand; Emmanuelle Comets; Céline M. Laffont; Marylore Chenel

2009-01-01

332

A Unified Theory of Impact Crises and Mass Extinctions: Quantitative Tests  

NASA Technical Reports Server (NTRS)

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.

Rampino, Michael R.; Haggerty, Bruce M.; Pagano, Thomas C.

1997-01-01

333

HE friction sensitivity oblique impact sensitivity of explosives the skid test & half-inch gap sensitivity test. Quarterly report, April 1970June 1970  

Microsoft Academic Search

Oblique impact tests were performed on RX-04-DS and on the extrusion cast explosive RX-08-AZ. Partial reactions were observed on RX-04-DS at 5.0â², 45° and at 1.25â², 14°; no reactions were observed with RX-08-AZ in the severest of tests. Vertical drop tests were performed on 6 inch-diameter hemispheres of LX-04-1. Results are tabulated. A series of accelerometer instrumented oblique impact tests

Van Velkinburgh

1997-01-01

334

HE friction sensitivity. Oblique impact sensitivity of explosives: The skid test and half-inch gap sensitivity test. Quarterly report, January--March, 1970  

Microsoft Academic Search

Vertical drop tests were completed on several explosives. Results are given and discussed. Oblique impact tests were performed on the extrusion cast explosive RX-08-AZ. No reactions were observed in the severest of impacts. Half-inch gap test series were performed on two lots of LX-09-0. Results are tabulated. No experimental work with the friction test apparatus was done this period.

Velkinburgh; J. H. van

1970-01-01

335

High-speed impact test using an inertial mass and an optical interferometer.  

PubMed

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. PMID:23902115

Jin, T; Watanabe, K; Prayogi, I A; Takita, A; Mitatha, S; Djamal, M; Jia, H Z; Hou, W M; Fujii, Y

2013-07-01

336

Inspection of Impact Damage in Honeycomb Composite by Espi, Thermography and Ultrasonic Testing  

NASA Astrophysics Data System (ADS)

Honeycomb composites are now fairly widely used in civilian and military aircraft structures. Common defects found in these materials are delaminations by impact damage and their presence will lead to structural weaknesses which could lead failure of the airframe structures. It is important to develop effective non-destructive testing procedures to identify these defects and increase the safety of aircraft travel. This paper describes the detection technique of impact damage defect using thermography and ESPI. The results obtained with the two techniques are compared with ultrasonic C-scan testing. The investigation shows that both imaging NDT methods are able to identify the presence of artificial defect and impact damage. The adoption of the thermography allowed significant advantages in inspection condition, and gives smaller error in quantitative estimation of defects.

Choi, Manyong; Park, Jeonghak; Kim, Wontae; Kang, Kisoo

337

Head impact mechanisms of a child occupant seated in a child restraint system as determined by impact testing.  

PubMed

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. PMID:22869307

Yoshida, Ryoichi; Okada, Hiroshi; Nomura, Mitsunori; Mizuno, Koji; Tanaka, Yoshinori; Hosokawa, Naruyuki

2011-11-01

338

Threshold Studies on TNT, Composition b, C-4, and ANFO Explosives using the Steven Impact Test.  

National Technical Information Service (NTIS)

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 ANF...

K. S. Vandersall L. L. Stwitzer P. Garcia

2006-01-01

339

Impact Testing of Restraint Devices Used with Handicapped Children in Bus Seats and Wheelchairs.  

National Technical Information Service (NTIS)

A series of 16 sled impact tests were conducted at the Highway Safety Research Institute sled facility in order to evaluate the effectiveness of restraint devices and systems currently being used for the transport of school bus and wheelchair-seated handi...

L. W. Schneider J. W. Melvin

1978-01-01

340

The Impact of the 2004 Hurricanes on Florida Comprehensive Assessment Test Scores: Implications for School Counselors  

ERIC Educational Resources Information Center

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…

Baggerly, Jennifer; Ferretti, Larissa K.

2008-01-01

341

Reconstruction of dynamic forces during impact tests of a crushable structure  

Microsoft Academic Search

A force reconstruction technique is being used to assess the dynamic performance of a crushable structure (a bomb nose) in both the axial (90°) and slapdown (30°) impact conditions. The dynamic force characteristics for the current nose design, determined from these tests, will be used to write a dynamic force specification for a new nose design that will replace the

V. I. Bateman; T. G. Carne; R. L. Mayes; N. T. Davie

1993-01-01

342

A Protocol System for Testing Biohazardous Materials in an Impact Biomechanics Research Facility  

Microsoft Academic Search

This article presents a protocol system, comprised of a review process and a series of checklists, that was developed for testing cadaveric tissue in an impact biomechanics research facility. The use of cadaveric tissue may expose personnel to bloodborne pathogens including HIV and hepatitis B, which have been shown to remain virulent in a cadaver for several weeks after death.

Stefan M. Duma; Rodney W. Rudd; Jeff R. Crandall

1999-01-01

343

Constitutive behavior, texture and damage evolution in BCC metal using taylor impact test  

Microsoft Academic Search

To capture the evolution of anisotropy in textured metals under high rate conditions, we developed a method that enables us to digitally resolve this event. Using a Taylor Anvil Test Facility, we dynamically deformed unalloyed Ta, while capturing real time digital images of the radial flow at the impact surface. We measured the elliptical footprint and plotted its eccentricity (ratio

C. P. Trujillo; Gray; S. R. Chen; R. L. Chavez

2004-01-01

344

Laboratory wind tunnel testing of three commonly used saltation impact sensors  

Microsoft Academic Search

Saltation Impact Sensors (SIS) of acoustic and piezo-electric design are increasingly used to study wind erosion in the laboratory and in the field. In spite of their wide-spread use, little is known about how to compare data collected with the different types of SIS or what physical limitations may exist. We tested four each of the Saltiphone, an acoustic sensor,

R. Scott Van Pelt; Piet Peters; Saskia Visser

2009-01-01

345

Development of a High Temperature Single Impact Rain Erosion Test Capability.  

National Technical Information Service (NTIS)

A single impact rain erosion test capability has been developed to obtain data on fiber loaded Teflon (e.g. Duroid) ablative radome materials at temperatures up to their ablating temperature (approx. 1250 F). This effort was undertaken as a result of the ...

K. N. Letson S. P. Risner

1984-01-01

346

Development of apparatus for magnetic measurements of Charpy impact test pieces  

Microsoft Academic Search

Since magnetic properties of ferromagnetic steels have a good correlation with their mechanical properties, those mechanical properties will be evaluated by magnetic measurements. An apparatus for measurement of BH curves of Charpy impact test pieces was therefore developed in order to evaluate the integrity of nuclear reactor pressure vessels nondestructively. In this paper, the operation of developed apparatus is demonstrated

Hiroaki Kikuchi; Mamoru Harada; Katsuyuki Ara; Yasuhiro Kamada; Satoru Kobayashi; Seiki Takahashi

2007-01-01

347

PATTERNS OF WHEELCHAIR RESPONSE AND SEATING-SYSTEM FAILURES IN FRONTAL-IMPACT SLED TESTS  

Microsoft Academic Search

Data from 259 frontal impact sled tests of commercial wheelchairs and seating systems were compiled and retrospectively analyzed. These data have general application to the development of additional design and performance requirements for transit wheelchair (WC) standards, and are specifically needed to guide the design and performance specifications of a reusable surrogate wheelchair base (SWCB) that can be used for

Miriam A. Manary; Laura M. Woodruff; Gina E. Bertocci; Lawrence W. Schneider

348

Testing Younger Dryas ET Impact (YDB) Evidence at Hall's Cave, Texas  

Microsoft Academic Search

Hall's Cave, Kerrville County Texas, 167 km WSW of Austin, provides a unique opportunity for testing the presence of a chronostratigraphic datum (YDB layer) containing rare and exotic proxies, including nanodiamonds, aciniform soot, and magnetic spherules, the origins of which remain controversial, but possibly derive from a cosmic impact ~12,900 CAL BP. The karst-collapse cave in Cretaceous limestone on the

T. W. Stafford; E. Lundelius; J. Kennett; D. J. Kennett; W. S. Wolbach

2009-01-01

349

The impact of response to the results of diagnostic tests for malaria: cost-benefit analysis  

PubMed Central

Objective Rapid diagnostic tests for malaria seem cost effective in standard analyses, but these do not take account of clinicians’ response to test results. This study tested the impact of clinicians’ response to rapid diagnostic test or microscopy results on the costs and benefits of testing at different levels of malaria transmission and in different age groups. Design Cost-benefit analysis using a decision tree model and clinical data on the effectiveness of diagnostic tests for malaria, their costs, and clinicians’ response to test results. Setting Tanzania. Methods Data were obtained from a clinical trial of 2425 patients carried out in three settings of varying transmission. Results At moderate and low levels of malaria transmission, rapid diagnostic tests were more cost beneficial than microscopy, and both more so than presumptive treatment, but only where response was consistent with test results. At the levels of prescription of antimalarial drugs to patients with negative tests that have been found in observational studies and trials, neither test methodis likely to be cost beneficial, incurring costs 10-250% higher, depending on transmission rate, than would have been the case with fully consistent responses to all test results. Microscopy becomes more cost beneficial than rapid diagnostic tests when its sensitivity under operational conditions approaches that of rapid diagnostic tests. Conclusions Improving diagnostic methods, including rapid diagnostic tests, can reduce costs and enhance the benefits of effective antimalarial drugs, but only if the consistency of response to test results is also improved. Investing in methods to improve rational response to tests is essential. Economic evaluations of diagnostic tests should take into account whether clinicians’ response is consistent with test results.

2008-01-01

350

The Impact of Cognitive Testing on the Welfare of Group Housed Primates  

PubMed Central

Providing cognitive challenges to zoo-housed animals may provide enriching effects and subsequently enhance their welfare. Primates may benefit most from such challenges as they often face complex problems in their natural environment and can be observed to seek problem solving opportunities in captivity. However, the extent to which welfare benefits can be achieved through programmes developed primarily for cognitive research is unknown. We tested the impact of voluntary participation cognitive testing on the welfare of a socially housed group of crested macaques (Macaca nigra) at the Macaque Study Centre (Marwell Zoo). First, we compared the rate of self-directed and social behaviours on testing and non-testing days, and between conditions within testing days. Minimal differences in behaviour were found when comparing testing and non-testing days, suggesting that there was no negative impact on welfare as a result of cognitive testing. Lipsmacking behaviours were found to increase and aggressive interaction was found to decrease in the group as a result of testing. Second, social network analysis was used to assess the effect of testing on associations and interactions between individuals. The social networks showed that testing subjects increased their association with others during testing days. One interpretation of this finding could be that providing socially housed primates with an opportunity for individuals to separate from the group for short periods could help mimic natural patterns of sub-group formation and reunion in captivity. The findings suggest, therefore, that the welfare of captive primates can be improved through the use of cognitive testing in zoo environments.

Whitehouse, Jamie; Micheletta, Jerome; Powell, Lauren E.; Bordier, Celia; Waller, Bridget M.

2013-01-01

351

Assessing the social impact of direct-to-consumer genetic testing: understanding sociotechnical architectures.  

PubMed

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. PMID:20601894

Parthasarathy, Shobita

2010-09-01

352

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

NASA Technical Reports Server (NTRS)

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.

Nettles, Alan T.

1991-01-01

353

MoSi2-Base Hybrid Composite Passed Engine Test  

NASA Technical Reports Server (NTRS)

The intermetallics compound molybdenum disilicide (MoSi2) is an attractive high-temperature structural material for advanced engine applications. It has excellent oxidation resistance, a high melting point, relatively low density, and high thermal conductivity, and it is easily machined. Past research'at the NASA Lewis Research Center has resulted in the development of a hybrid composite consisting of a MoSi2 matrix reinforced with silicon nitride (Si3N4) Particulate and silicon carbide (SiC) fibers. This composite has demonstrated attractive strength, toughness, thermal fatigue, and oxidation resistance, including resistance to "pest" oxidation. These properties attracted the interest of the Office of Naval Research and Pratt & Whitney, and a joint NASA/Navy/Pratt & Whitney effort was developed to continue to mature the MoSi2 Composite technology. A turbine blade outer air seal, which was part of the Integrated High Performance Turbine Engine Technology (IHPTET) program, was chosen as a first component on which to focus. The first tasks of the materials development effort were to develop improved processing methods to reduce costs and to use fine-diameter fibers that enable the manufacturing of complex shapes. Tape-casting methods were developed to fully infiltrate the fine SiC fibers with matrix powders. The resulting composites were hot pressed to 100-percent density. Composites with cross-plied fiber architectures with 30 vol. % hi-nicalon SiC fibers and 30 vol. % nitride particles are now made routinely and demonstrate a good balance of properties. The next task entailed the measurement of a wide variety of mechanical properties to confirm the suitability of this composite in engines. In particular, participants in this effort demonstrated that composites made with Hi-Nicalon fibers had strength and toughness properties equal to or better than those of the composites made with the large-diameter fibers that had been used previously. Another critically important property measured was impact resistance. Aircraft engine components require sufficient toughness to resist manufacturing defects, assembly damage, stress concentrations at notches, and foreign object damage. Engine company designers indicated that impact resistance would have to be measured before they would seriously consider these types of composites. The Charpy V-notch test was chosen to assess impact resistance, and both monolithic and composite versions Of MOSi2 were tested from -300 to 1400 C. The results (see the following graphs) show that nitride-particulate-reinforced MoSi2 exhibited impact resistance higher than that of many monolithic ceramics and intermetallics, and that the fiber-reinforced composites had even higher values, approaching that of cast superalloys.

Keith, Theo G., Jr.; Hebsur, Mohan

1998-01-01

354

Simulation of an Impact Test of the All-Composite Lear Fan Aircraft  

NASA Technical Reports Server (NTRS)

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.

Stockwell, Alan E.; Jones, Lisa E. (Technical Monitor)

2002-01-01

355

Impact Testing on Reinforced Carbon-Carbon Flat Panels with Ice Projectiles for the Space Shuttle Return to Flight Program  

NASA Technical Reports Server (NTRS)

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.

Melis, Matthew E.; Revilock, Duane M.; Pereira, Michael J.; Lyle, Karen H.

2009-01-01

356

LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN  

SciTech Connect

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.

Chidester, S K; Vandersall, K S; Switzer, L L; Tarver, C M

2005-07-18

357

LX-04 Violence Measurements-Steven Tests Impacted by Projectiles Shot from a Howitzer Gun  

NASA Astrophysics Data System (ADS)

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.

Chidester, Steven K.; Vandersall, Kevin S.; Switzer, Lori L.; Tarver, Craig M.

2006-07-01

358

High-speed impact test of an air-transportable plutonium nitrate shipping container  

SciTech Connect

To obtain information on package response for comparison with other test environments, a high-speed impact test was performed on a modified Federal Republic of Germany 18B plutonium nitrate air-transportable container. The container, modified with reinforcing rings for improved crush resistance around the inner tube assembly, was impacted at a velocity of 137 m/s onto an unyielding surface. Substantial crushing of the foam overpack and extensive deformation of the container cavity occurred, causing release of the liquid surrogate contents from the titanium shipping container. The container damage resulting from the high-speed pulldown test was more severe than that from a 185-m free fall onto a semirigid surface by a similar container or the crush environment produced by a 9-m drop of a 2-Mg block onto the container resting on an unyielding surface.

Yoshimura, H.R.; Pope, R.B.; Leisher, W.B.; Joseph, B.J.

1980-04-01

359

Test and Analysis of Foam Impacting a 6x6 Inch RCC Flat Panel  

NASA Technical Reports Server (NTRS)

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.

Lessard, Wendy B.

2006-01-01

360

Rapid impact testing for quantitative assessment of large populations of bridges  

NASA Astrophysics Data System (ADS)

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.

Zhou, Yun; Prader, John; Devitis, John; Deal, Adrienne; Zhang, Jian; Moon, Franklin; Aktan, A. Emin

2011-03-01

361

Low amplitude impact of PBX 9501: Modified Steven spigot gun tests  

SciTech Connect

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.

Idar, D.J.; Lucht, R.A.; Straight, J.W. [and others

1998-12-01

362

Impacts of four communication programs on HIV testing behavior in South Africa.  

PubMed

This paper aims to evaluate the impacts of four communication programs on promoting HIV testing behavior among sexually active individuals in South Africa. The four programs, implemented by Johns Hopkins Health and Education in South Africa, are aimed to promote HIV prevention behaviors, as well as gender-based violence prevention, tuberculosis screening and treatment, and reduction of alcohol consumption. Launched between 2009 and 2010, they all promoted HIV testing. Data came from the population-based Third National AIDS Communication Survey 2012; 6004 men and women who had sex within the last 12 months were included in the analysis. Multiple causal attribution analysis is used to justify causal reference and estimate the impact of communication programs. Findings indicate significant direct and indirect effects of the programs on HIV testing behavior. Indirect effects worked through increasing one's likelihood of perceiving that their friends were tested and the probability of talking about HIV testing with sex partners and friends, which in turn increased the likelihood of HIV testing. Findings suggest multiple angles from which communication programs can promote HIV testing. The study also demonstrates the use of multiple statistical techniques for causal attribution in a post-only design, where randomization is not possible. PMID:24702270

Do, Mai; Kincaid, D Lawrence; Figueroa, Maria Elena

2014-09-01

363

Spin Testing for Durability Began on a Self-Tuning Impact Damper for Turbomachinery Blades  

NASA Technical Reports Server (NTRS)

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 force to the rotating shaft itself at frequencies independent of the rotor speed. During testing, blade vibration is monitored with strain gauges and laser displacement probes.

Duffy, Kirsten; Mehmed, Oral

2003-01-01

364

Application of subsize specimens in nuclear plant life extension  

Microsoft Academic Search

The US Department of Energy is sponsoring a research effort through Sandia National Laboratories and the University of Missour-Rolla to test a correlation for the upper shelf energy (USE) values obtained from the impact testing of subsize Charpy V-notch specimens to those obtained from the testing of full size samples. The program involves the impact testing of unirradiated and irradiated

S. T. Rosinski; A. S. Kumar; S. C. Cannon; M. L. Hamilton

1991-01-01

365

Hypervelocity impact testing of the Space Station utility distribution system carrier  

NASA Technical Reports Server (NTRS)

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.

Lazaroff, Scott

1993-01-01

366

An 810 ft/sec soil impact test of a 2-foot diameter model nuclear reactor containment system  

NASA Technical Reports Server (NTRS)

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.

Puthoff, R. L.

1972-01-01

367

Characterization, testing and constitutive modelling of an impact-modified polypropylene  

NASA Astrophysics Data System (ADS)

Impact modified polypropylenes (or TPOs) are polymer blends of isotactic polypropylene (iPP), ethylene-propylene-diene monomer elastomer (EPDM), and high density polyethylene (HDPE). Currently, TPOs are extensively used in impact applications, such as car bumpers. However, the design process of TPO parts for impact applications is still an expensive, trial-and-error procedure. In this project, we aim to develop a material model with specific physical bases to represent a TPO material, so that TPO part design can be effective and efficient. In order to achieve our objective, morphology characterization and mechanical testing have been conducted to examine the intrinsic mechanisms of TPO. Tests were conducted over a broad range of strain rates using both a servohydraulic apparatus and an Aluminum split Hopkinson pressure bar. The TPO system we examined is multi-phasic in which an EPDM and HDPE blend forms the minor domain, distributed in the iPP matrix. The large deformation TPO response includes strain rate dependent initial stiffness; temperature, deformation state and strain rate dependent yield; temperature and deformation state dependent strain hardening. Its response is not unlike that of glassy polymers in many ways, owing to the flexibility of the iPP matrix, however the TPO shows a moderate strain hardening rate and little strain recovery upon unloading. A three-dimensional, four-element constitutive model has been developed for this TPO. The model includes rate dependent stiffness, rate and temperature dependent yield, temperature dependent strain hardening, and crystallographic slip. The model has been examined to be robust over a wide range of strain rates from quasi-static to impact, and predictive of different deformation states, such as uniaxial compression and plane strain compression. The model has been shown to capture the post-yield thermal softening and apparent lack of post-yield strain hardening at impact test conditions.

Wang, Yan

2002-01-01

368

COATINGS' MICRO ABRASION INVESTIGATED BY THE INCLINED IMPACT TEST AT VARIOUS LOADS UNDER DRY AND LUBRICATED CONDITIONS  

Microsoft Academic Search

The impact test has clearly emerged as an important technology for the prediction of coatings cohesive, adhesive and fatigue failure, further enabling the establishment of PVD films Smith and Woehler diagrams. In the present paper the abrasive wear of a well-adherent (Ti46Al54)N coating was investigated by the inclined impact test, at impact loads higher, equal or lower than the fatigue

K.-D. Bouzakis; A. Asimakopoulos; G. Skordaris; E. Pavlidou; G. Erkens

369

Experimental and Modeling Studies of Crush, Puncture, and Perforation Scenarios in the Steven Impact Test  

SciTech Connect

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.

Vandersall, K S; Chidester, S K; Forbes, J W; Garcia, F; Greenwood, D W; Switzer, L L; Tarver, C M

2002-06-28

370

Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test  

SciTech Connect

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.

Vandersall, K S; Switzer, L L; Garcia, F

2005-09-26

371

Evaluation of the accuracy of side impact crash test reconstructions - biomed 2009.  

PubMed

Each year in the U.S., vehicle side crashes result in over 6,000 fatalities. Delta-V, the vehicle change in velocity, is a widely used measure of crash injury risk in real world crashes. However, delta-V is difficult to estimate accurately for side crashes using reconstruction codes such as CRASH3. Such codes are the source of a large portion of the delta-V values in crash databases, so their accuracy has a direct impact on injury risk prediction data. In this study, delta-V was first reconstructed for a series of 42 staged side impact crash tests using CRASH3. This reconstructed delta-V was then compared to the delta-V recorded by the crash test instrumentation to determine the accuracy of the reconstructed value. PMID:19369771

Johnson, Nicholas; Hampton, Carolyn; Gabler, Hampto C

2009-01-01

372

Environmental impact assessment of tailings dispersal from a uranium mine using toxicity testing protocols  

SciTech Connect

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.

Rippon, G.D. [Environmental Protection Agency, Canberra (Australia); Riley, S.J. [Univ. of Western Sydney-Nepean, Kingswood (Australia)

1996-12-01

373

Test and Treat DC: Forecasting the Impact of a Comprehensive HIV Strategy in Washington DC  

PubMed Central

Background US and international agencies have signaled their commitment to containing the HIV epidemic via early case identification and linkage to antiretroviral therapy (ART) immediately upon diagnosis. We forecast outcomes of this approach if implemented in Washington DC. Methods Using a mathematical model of HIV case detection and treatment, we evaluate combinations of HIV screening and ART initiation strategies. We define current practice as no regular screening program and ART at ?350/?l, and test and treat as annual screening and ART upon diagnosis. Outcomes include life expectancy of HIV-infected persons and changes in the population time with transmissible HIV RNA. Data, largely from DC, include undiagnosed HIV prevalence 0.6%, annual incidence 0.13%, 31% test offer, 60% acceptance, and 50% linkage to care. Input parameters, including optimized ART efficacy, are varied in sensitivity analyses. Results Projected life expectancies, from an initial mean age 41 years, for current practice, test and treat, and test and treat with optimized ART are 23.9, 25.0, and 25.6 years. Compared to current practice, test and treat leads to a 14.7% reduction in time spent with transmissible HIV RNA in the next 5 years; test and treat with optimized ART results in a 27.2% reduction. Conclusions An expanded HIV test and treat program in Washington DC will increase life expectancy of HIV-infected patients but will have a modest impact on HIV transmission over the next five years and is unlikely to halt the HIV epidemic. Summary The CEPAC model shows a test and treat strategy in Washington DC would result in a substantial clinical impact to HIV-infected individuals. Results suggest a need to temper expectations regarding the extent to which test and treat will control the epidemic.

Walensky, Rochelle P.; Paltiel, A. David; Losina, Elena; Morris, Bethany L.; Scott, Callie A.; Rhode, Erin R.; Seage, George R.; Freedberg, Kenneth A.

2010-01-01

374

The WRAIR Projectile Concussive Impact Model of Mild Traumatic Brain Injury: Re-design, Testing and Preclinical Validation.  

PubMed

The WRAIR projectile concussive impact (PCI) model was developed for preclinical study of concussion. It represents a truly non-invasive closed-head injury caused by a blunt impact. The original design, however, has several drawbacks that limit the manipulation of injury parameters. The present study describes engineering advancements made to the PCI injury model including helmet material testing, projectile impact energy/head kinematics and impact location. Material testing indicated that among the tested materials, 'fiber-glass/carbon' had the lowest elastic modulus and yield stress for providing an relative high percentage of load transfer from the projectile impact, resulting in significant hippocampal astrocyte activation. Impact energy testing of small projectiles, ranging in shape and size, showed the steel sphere produced the highest impact energy and the most consistent impact characteristics. Additional tests confirmed the steel sphere produced linear and rotational motions on the rat's head while remaining within a range that meets the criteria for mTBI. Finally, impact location testing results showed that PCI targeted at the temporoparietal surface of the rat head produced the most prominent gait abnormalities. Using the parameters defined above, pilot studies were conducted to provide initial validation of the PCI model demonstrating quantifiable and significant increases in righting reflex recovery time, axonal damage and astrocyte activation following single and multiple concussions. PMID:24756867

Leung, Lai Yee; Larimore, Zachary; Holmes, Larry; Cartagena, Casandra; Mountney, Andrea; Deng-Bryant, Ying; Schmid, Kara; Shear, Deborah; Tortella, Frank

2014-08-01

375

Normalizing and scaling of data to derive human response corridors from impact tests.  

PubMed

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. PMID:24726322

Yoganandan, Narayan; Arun, Mike W J; Pintar, Frank A

2014-06-01

376

THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST  

Microsoft Academic Search

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

K S Vandersall; L L Switzer; F Garcia

2006-01-01

377

Hydrogen embrittlement of a Ti Al Zr alloy evaluated by impact test method  

Microsoft Academic Search

The characteristics of hydriding and hydrogen embrittlement of a TiAlZr alloy were evaluated by the impact test method. The results indicated that the hydrides in TiAlZr alloy formed as platelets and were identified as face-centered cubic ?-hydride. At room temperature, the specimen showed great sensitivity to embrittlement in ductility by hydrogen. The hydrides formed promoted the crack propagation in the

Y. Z. Liu; X. T. Zu; C. Li; S. Y. Qiu; W. J. Li; X. Q. Huang

2005-01-01

378

Modeling board-level four-point bend fatigue and impact drop tests  

Microsoft Academic Search

In this paper, modeling and simulation of board-level four-point bend fatigue and impact tests were investigated for 7 mm times 7 mm VQFN (48 I\\/O) assembly and 15 mm times 15 mm FBGA (324 I\\/O) assembly with Sn-Ag-Cu lead-free solder and OSP board surface finish. For cyclic bending fatigue, four-point bend cyclic loading at room temperature (25degC) and at high

Chea FX; J. H. L. Pang

2006-01-01

379

Development of 1232°C (2250°F) Erosion and Impact Tests for Thermal Barrier Coatings  

Microsoft Academic Search

High temperature erosion and impact texts were developed for evaluation of thermal barrier coating (TBC) systems that are being generated for the High-Speed Civil Transport supersonic aircraft under NASA's Enabling Propulsion Materials program. The TBC-coated test specimen is a 6.1-mm (0.24-inch) diameter cylindrical pin. Twelve pins are mounted on a carousel with a pitch diameter of 46 mm (1.813 inch).

Robert W. Bruce

1998-01-01

380

Compression and impact testing of two-layer composite pyramidal-core sandwich panels  

Microsoft Academic Search

Quasi-static uniform compression tests and low-velocity concentrated impact tests were conducted to reveal the failure mechanisms and energy absorption capacity of two-layer carbon fiber composite sandwich panels with pyramidal truss cores. Three different volume-fraction cores (i.e., with different relative densities) were fabricated: 1.25%, 1.81%, and 2.27%. Two-layer sandwich panels with identical volume-fraction cores (either 1.25% or 2.27%), and also stepwise

Jian Xiong; Ashkan Vaziri; Li Ma; Jim Papadopoulos; Linzhi Wu

381

Impact  

NASA Technical Reports Server (NTRS)

Impact, emergency escape and crash survival protection are studied. Accleration, the G system of units, data interpretation, and human tolerance limits are summarized, along with physiological and biochemical response to impact. Biomechanical factors of impact are also cited.

Snyder, R. G.

1973-01-01

382

An investigation on the impact fatigue characteristics of valve leaves for small hermetic reciprocating compressors in a new automated test system  

Microsoft Academic Search

This paper presents an investigation on the impact fatigue characteristics of valve leaves that are prevalently used in hermetic reciprocating compressors especially for the household type refrigerators. A unique automated impact fatigue test system has been designed and produced, which enables to carry out impact fatigue tests of the compressor valve leaves under the desired impact velocities. The test system

A. C. Altunlu; I. Lazoglu; E. Oguz; S. Kara

2012-01-01

383

Uniform Foam Crush Testing for Multi-Mission Earth Entry Vehicle Impact Attenuation  

NASA Technical Reports Server (NTRS)

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.

Patterson, Byron W.; Glaab, Louis J.

2012-01-01

384

Capabilities of NASA/Marshall Space Flight Center's Impact Testing Facility  

NASA Technical Reports Server (NTRS)

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.

Hovater, Mary; Hubbs, Whitney; Finchum, Andy; Evans, Steve; Nehls, Mary

2006-01-01

385

The overall impact of testing on medical student learning: quantitative estimation of consequential validity.  

PubMed

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 the learning gains attained through educational assessments. To approach this question, we estimate achieved learning within a medical school environment that optimally utilizes educational assessments. We compare this estimate to learning that might be expected in a medical school that employs no educational assessments. Effect sizes are used to estimate testing's total impact on learning by summarizing three effects; the direct effect, the indirect effect, and the selection effect. The literature is far from complete, but the available evidence strongly suggests that each of these effects is large and the net cumulative impact on learning in medical education is over two standard deviations. While additional evidence is required, the current literature shows that testing within medical education makes a strong positive contribution to learning. PMID:22886140

Kreiter, Clarence D; Green, Joseph; Lenoch, Susan; Saiki, Takuya

2013-10-01

386

THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST  

SciTech Connect

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.

Vandersall, K S; Switzer, L L; Garcia, F

2006-06-20

387

Statistical variations in impact resistance of steel fiber-reinforced concrete subjected to drop weight test  

SciTech Connect

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.

Nataraja, M.C. [Sri Jayachamarajendra College of Engineering, Mysore (India). Faculty in Civil Engineering] [Sri Jayachamarajendra College of Engineering, Mysore (India). Faculty in Civil Engineering; Dhang, N.; Gupta, A.P. [Indian Inst. of Tech., Kharagpur (India). Dept. of Civil Engineering] [Indian Inst. of Tech., Kharagpur (India). Dept. of Civil Engineering

1999-07-01

388

Space Shuttle solid rocket booster initial water impact loads and dynamics - Analysis, tests, and flight experience  

NASA Technical Reports Server (NTRS)

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.

Kross, D. A.; Kiefling, L. A.; Murphy, N. C.; Rawls, E. A.

1983-01-01

389

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

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…

Cocke, Erin F.; Buckley, Jack; Scott, Marc A.

2011-01-01

390

Water Impact Test and Simulation of a Composite Energy Absorbing Fuselage Section  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

391

Determination of peak deflections from human surrogates using chestbands in side impact tests.  

PubMed

To understand the biomechanics of the human body in motor vehicle environments, physical models including anthropomorphic test devices (ATD) and biological models (postmortem human surrogates) are used, and sled tests are conducted. Deflection is often used as a biomechanical variable to characterize the effects of impact loading and derive injury criteria. The objective of the present study was to evaluate different techniques and recommend a methodology to determine the peak thorax and abdominal deflections from temporal contours using chestbands in oblique lateral impacts. The side impact ATD WorldSID representing human surrogates was positioned on a seat. The seat was rigidly fixed to the platform of an acceleration sled. The oblique load-wall fixed to the sled consisted of separate and adjustable plates to contact the shoulder, thorax, abdomen, and pelvis. Two 59-gage chestbands were wrapped on the thorax and abdomen. Tests were conducted at low, medium, and high velocities (3.4, 6.7, and 7.5m/s) and three methods, termed the spine-sternum, bilateral, and spine-box, were used to determine the global peak deflection and its angulation. Results indicated that all three methods produced very similar angulations, for all velocity tests, and at both thorax and abdominal regions. However, maximum deflections were the lowest in the spine-sternum, followed by bilateral and spine-box methods, with one exception. Based on the development of deflection contours, locations used in the definitions of the origin, and accuracy in identifying critical locations/points in time-varying contours, results of the present study indicate that the bilateral method is the optimum procedure to determine the oblique peak deflection vector in biomechanical tests. PMID:23357337

Yoganandan, Narayan; Humm, John R; Pintar, Frank A; Maiman, Dennis J

2013-08-01

392

HE friction sensitivity oblique impact sensitivity of explosives (the skid test). Quarterly report, July--September 1971  

Microsoft Academic Search

Additional oblique impact tests were performed on RX-25-AA in an attempt to determine its initiation threshold. Several more oblique impact tests were conducted on the LX-10-0 variants. Experimental results from some of the tests conducted last period on the LX-10-0 variant are presented (accelerator records had not been analyzed at the close of the last reporting period). An instrumented vertical

Van Velkinburgh

1997-01-01

393

Evaluating cover depth of steel fiber reinforced concrete using impact-echo testing  

NASA Astrophysics Data System (ADS)

The purpose of this research is to estimate of the cover depth of steel fiber reinforced concrete using the impact-echo testing. In order to evaluate the security of the construction, usually need to estimate the cover depth of the reinforced concrete. At present, the examination technique of the cover depth of the reinforced concrete without the steel fiber is mainly applied in the magnetic and electrical methods, its rapid detection and good results. But the research of the reactive powder concrete be gradually progress, with the steel fiber concrete structure will be increased, if should still operate the examination with the magnetic and electrical methods, theoretically the steel fiber will have the interference to its electromagnetism field. Therefore, this research designs four kinds of reinforced concrete plate that include different steel fiber contents, to evaluate test results of estimate of the cover depth of the reinforcing bar. The results showed that: estimate of the cover depth of steel fiber reinforced concrete reinforcing bar using the impact-echo testing, the variety of the steel fiber content does not have much influence, the test measurement error within ± 10%, and the most important source of uncertainty is the velocity of concrete.

Lin, Yu-Feng

2014-04-01

394

Impact dynamics research facility for full-scale aircraft crash testing  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

395

A 640 foot per second impact test of a two foot diameter model nuclear reactor containment system without fracture  

NASA Technical Reports Server (NTRS)

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.

Puthoff, R. L.

1971-01-01

396

Quantifying the impact of future Sandage-Loeb test data on dark energy constraints  

NASA Astrophysics Data System (ADS)

The Sandage-Loeb (SL) test is a unique method to probe dark energy in the ``redshift desert'' of 2lesssimzlesssim5, and thus it provides an important supplement to the other dark energy probes. Therefore, it is of great importance to quantify how the future SL test data impact on the dark energy constraints. To avoid the potential inconsistency in data, we use the best-fitting model based on the other geometric measurements as the fiducial model to produce 30 mock SL test data. The 10-yr, 20-yr, and 30-yr observations of SL test are analyzed and compared in detail. We show that compared to the current combined data of type Ia supernovae, baryon acoustic oscillation, cosmic microwave background, and Hubble constant, the 30-yr observation of SL test could improve the constraint on ?m by about 80% and the constraint on w by about 25%. Furthermore, the SL test can also improve the measurement of the possible direct interaction between dark energy and dark matter. We show that the SL test 30-yr data could improve the constraint on ? by about 30% and 10% for the Q = ?H?c and Q = ?H?de models, respectively.

Geng, Jia-Jia; Zhang, Jing-Fei; Zhang, Xin

2014-07-01

397

Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test  

NASA Astrophysics Data System (ADS)

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.

Switzer, Lori L.; Vandersall, Kevin S.; Chidester, Steven K.; Greenwood, Daniel W.; Tarver, Craig M.

2004-07-01

398

Testing, Modeling and System Impact of Metabolic Heat Regenerated Temperature Swing Adsorption  

NASA Technical Reports Server (NTRS)

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.

Lacomini, Christine S.; Powers, Aaron; Lewis, Matthew; Linrud, Christopher; Waguespack, Glenn; Conger, Bruce; Paul, Heather L.

2008-01-01

399

Impact of the emergence of designer drugs upon sports doping testing.  

PubMed

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. PMID:22191595

Teale, P; Scarth, J; Hudson, S

2012-01-01

400

Crushable structure performance determined from reconstructed dynamic forces during impact tests  

SciTech Connect

A force reconstruction technique has been used to assess the dynamic performance of a crushable structure (a bomb nose) in both the axial (90{degrees}) and slapdown (30{degrees}) impact conditions. The dynamic force characteristics for the nose design, determined from these test results, have been used to write a dynamic force specification for a new nose design that will replace the old nose. The dynamic forces are reconstructed from measured acceleration responses with the Sum of Weighted Accelerations Technique (SWAT) developed at Sandia National Laboratories. Axial characterizations for the old nose are presented from tests at two SNL facilities: a rocket rail launcher facility and an 18-Inch horizontal actuator facility. The characterizations for the old nose are compared to the characterizations for two new nose designs. Slapdown characterizations for the old nose are presented. Incorporation of the test results into a dynamic force specification is discussed.

Bateman, V.I.

1995-01-01

401

Flight test experience and controlled impact of a large, four-engine remotely piloted airplane  

NASA Technical Reports Server (NTRS)

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.

Kempel, R. W.; Horton, T. W.

1985-01-01

402

Flight test experience and controlled impact of a large, four-engine, remotely piloted airplane  

NASA Technical Reports Server (NTRS)

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.

Kempel, R. W.; Horton, T. W.

1985-01-01

403

Test and Analysis Correlation of Form Impact onto Space Shuttle Wing Leading Edge RCC Panel 8  

NASA Technical Reports Server (NTRS)

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.

Fasanella, Edwin L.; Lyle, Karen H.; Gabrys, Jonathan; Melis, Matthew; Carney, Kelly

2004-01-01

404

A Gas-Actuated Projectile Launcher for High-Energy Impact Testing of Structures  

NASA Technical Reports Server (NTRS)

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.

Ambur, Damodar R.; Jaunky, Navin; Lawson, Robin E.; Knight, Norman F., Jr.; Lyle, Karen H.

1999-01-01

405

Pressure scaled water impact test of a 12.5 inch diameter model of the Space Shuttle solid rocket booster  

NASA Technical Reports Server (NTRS)

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.

1982-01-01

406

Damage Detection and Impact Testing on Laminated and Sandwich Composite Panels  

NASA Technical Reports Server (NTRS)

This research investigates health monitoring of sandwich shell composites to determine if the Transmittance Functions (TF) are effective in determining the present of damage. The health monitoring test was conducted on the sandwich plates before and after low velocity impacts using the health monitoring technique given in TFs are a NDE (Nondestructive Evaluation) technique that utilizes the ratios of cross-spectrums to auto-spectrums between two response points on the sandwich composites. The test for transmittance was conducted on the same density foam core throughout the experiment. The test specimens were 17.8 cm by 25.4 cm in dimension. The external sheets (face sheets) were created from graphite/epoxy laminate with dimension of 1.58 mm thick. The polymethacrylide (Rohacell) foam core was 12.7 mm thick. These samples experienced a transformation in the TF that was considered the low velocity impact damage. The low velocity damage was observed in the TFs for the sandwich composites.

Hughes, Derke R.; Craft, William J.; Schulz, Mark J.; Naser, Ahmad S.; Martin, William N.

1998-01-01

407

LX-04 Violence Measurments: Steven Tests Impacted By Projectiles Shot From A Howitzer Gun  

NASA Astrophysics Data System (ADS)

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.

Chidester, Steven K.

2005-07-01

408

Model Investigation of Technique for Full Scale Landing Impact Tests at Simulated Lunar Gravity  

NASA Technical Reports Server (NTRS)

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

1965-01-01

409

Analysis of catalyst particle strength by impact testing: The effect of manufacturing process parameters on the particle strength  

Microsoft Academic Search

The mechanical strength of porous alumina catalyst carrier beads, used in the reforming units with continuous catalytic regeneration, was measured by impact testing. With this testing method particle strength can be measured at higher strain rates than the traditional crushing test method, hence providing a better simulation of pneumatic conveying and chute flow conditions, and also a large number of

Charlotte Subero-Couroyer; Mojtaba Ghadiri; Nathalie Brunard; Frédéric Kolenda

2005-01-01

410

The role of IS architecture planning in enhancing IS outsourcing's impact on IS performance : Its antecedents and an empirical test  

Microsoft Academic Search

Purpose – The purpose of this paper is to develop a conceptual model on the role that information systems (IS) architecture planning plays in enhancing IS outsourcing's impact on IS performance and to empirically test the model. Design\\/methodology\\/approach – Survey data were gathered and structural equation modeling technique is used to test hypotheses. Findings – The empirical test clearly demonstrates

Zhengzhong Shi

2010-01-01

411

Retrospective evaluation of the impact of functional immunotoxicity testing on pesticide hazard identification and risk assessment.  

PubMed

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. PMID:24601769

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

412

Failure mode analysis of lead-free solder joints under differential reflow profiles by high speed impact testing  

Microsoft Academic Search

The aim of this research is to investigate the mechanical behavior of lead-free solder for high speed impact. A high speed impact test was set up to measure the solder joint reliability. Differential impact speed and room temperature aging effect has been studied with Ni\\/Au substrate. Furthermore, two different solder alloys (96.5Sn-3Ag-0.5Cu, 98.5Sn-1Ag-0.5C) and three different reflow profiles are considered.

C. Y. Lin; Y. R. Chen; G. S. Shen; D. S. Liu; C. Y. Kuo; C. L. Hsu

2008-01-01

413

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection  

NASA Technical Reports Server (NTRS)

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.

Hernandez, Sonia; Barbee, Brent W.

2011-01-01

414

Testing the impact on natural risks' awareness of visual communication through an exhibition  

NASA Astrophysics Data System (ADS)

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 risk and demographics. In addition, the post-test included several satisfaction questions concerning the visual tools displayed in the exhibition. A statistical analysis of the changes between the pre- and post- tests allows to verify whether the exhibition has an impact on risk awareness or not. In order to deduce the attractiveness of each visual tool independently, the visitors' paths are tracked using RFID (Radio Frequency Identification) technique, from which their time spent around certain visuals can be assessed. These results also help to analyze the changes in risk awareness measured by the pre-test/post-test design. Direct observation of visitors' reactions and behaviors completed the methodology. This research hence helps to assess which visual tools are more suitable to communicate such topics not only to a community as a whole, but also to its sub-categories (e.g. adults vs. children, people with experience of natural disasters vs. people without). Moreover, it provides methodological improvements concerning effectiveness research in the field of risk communication. The first results of this research will be presented and discussed.

Charrière, Marie; Bogaard, Thom; Junier, Sandra; Malet, Jean-Philippe; Mostert, Erik

2014-05-01

415

Water impact test of aft skirt end ring, and mid ring segments of the Space Shuttle Solid Rocket Booster  

NASA Technical Reports Server (NTRS)

The results of water impact loads tests using aft skirt end ring, and mid ring segments of the Space Shuttle Solid Rocket Booster (SRB) are examined. Dynamic structural response data is developed and an evaluation of the model in various configurations is presented. Impact velocities are determined for the SRB with the larger main chute system. Various failure modes are also investigated.

1983-01-01

416

Investigation, Evaluation, and Application of Techniques for Correlating Rotorcraft Full-Scale Water Impact Tests Versus Analyses.  

National Technical Information Service (NTIS)

This report presents the results of applying various correlation techniques between aircraft water impact tests and analysis. Various relationships, such as between floor accelerations and panel pressures amplitudes or between time and frequency domains, ...

G. Wittlin M. Gamon

2004-01-01

417

Assessment of impacts at the advanced test reactor as a result of chemical releases at the Idaho Chemical Processing Plant.  

National Technical Information Service (NTIS)

This report provides an assessment of potential impacts at the Advanced Test Reactor Facility (ATR) resulting from accidental chemical spill at the Idaho Chemical Processing Plant (ICPP). Spills postulated to occur at the Lincoln Blvd turnoff to ICPP were...

A. S. Rood

1991-01-01

418

Comparison of fracture toughness and Charpy impact properties recovery by thermal annealing of irradiated reactor pressure vessel steels  

SciTech Connect

The objective of this investigation was to study the effects of thermal annealing on the recovery of the transition region toughness of reactor pressure vessel steels. The toughness was measured by Charpy V-notch impact energy and fracture initiation toughness, K{sub Jc}. The materials were A 533 grade B class 1 plate and a commercial reactor vessel submerged-arc weld irradiated at 288{degrees}C to neutron fluences of 1.0 to 2.5 {times} 101{degrees} neutrons/cm{sup 2} (> 1 MeV). The irradiated materials were annealed at 343 and 454{degrees}C for 1 week. The recently developed Weibull statistic/master curve approach was applied to analyze fracture toughness properties of unirradiated, irradiated, and irradiated/annealed pressure vessel steels. The effects of irradiation or annealing were determined by the shift in temperature of the Charpy V-notch curve at 41 J and the fracture toughness curve at 100 MPa{radical}m. After annealing at 454{degrees}C, the residual shifts in fracture toughness are approximately the same as the residual Charpy shifts. The differences observed in these residual shifts after annealing are approximately the same as differences in the radiation-induced shifts.

Sokolov, M.A.; McCabe, D.E.; Iskander, S.K.; Nanstad, R.K.

1995-12-01

419

Assessment of the TASER XREP blunt impact and penetration injury potential using cadaveric testing.  

PubMed

TASER International's extended range electronic projectile (XREP) is intended to be fired from a shotgun, impact a threat, and apply remote neuromuscular incapacitation. This study investigated the corresponding potential of blunt impact injury and penetration. Forty-three XREP rounds were deployed onto two male human cadaver torsos at impact velocities between 70.6 and 95.9 m/sec (232 and 315 ft/sec). In 42 of the 43 shots fired, the XREP did not penetrate the abdominal wall, resulting in superficial wounds only. On one shot, the XREP's nose section separated prematurely in flight, resulting in penetration. No bony fractures were observed with any of the shots. The viscous criterion (VC), blunt criterion (BC), and energy density (E/A) were calculated (all nonpenetrating tests, average ± 1 standard deviation: VC: 1.14 ± 0.94 m/sec, BC: 0.77 ± 0.15, E/A: 22.6 ± 4.15 J/cm(2)) and, despite the lack of injuries, were generally found to be greater than published tolerance values. PMID:23067043

Lucas, Scott R; McGowan, Joseph C; Lam, Tack C; Yamaguchi, Gary T; Carver, Matthew; Hinz, Andrew

2013-01-01

420

Safety Issues in the Nuclear Electric Propulsion Space Test Environmental Impact Statement  

NASA Astrophysics Data System (ADS)

The National Environmental Policy Act (NEPA), requires Federal agencies to prepare environmental impact statements (EIS) for actions which might have a significant impact on the human environment. Launching a nuclear reactor into Earth orbit is such an action. Although the normal operations of the space nuclear reactor may have a minimal effect on the human environment, launch accidents, criticality accidents, and inadvertent reentry of the reactor into the biosphere could have significant environmental impacts. Thus, an EIS must examine the proposed action and reasonable alternatives to allow the decdision makers to make better environmentally informed decisions. The issues related to reactor safety are of particular interest to both the public and to agency decision makers and, therefore, tend to be the most visible and controversial aspects of the EIS. The EIS also represents the major opportunity for direct public involvement in the decision-making process. This paper discusses the approach to nuclear reactor safety issues in the Nuclear Electric Propulsion Space Test EIS, which will examine the environmental issues related to the proposed launching of the Topaz II reactor.

Glover, William A.

1994-07-01

421

On the development of an impact-loaded wedge test using ORVIS  

NASA Astrophysics Data System (ADS)

Experiments using a wedge-shaped explosive sample shocked with an attenuator-explosive booster are historically used to provide data for fitting an empirical relationship between the input stress and shock-to-detonation run distance. Recent problems with plane wave lens availability and increased needs for characterizing novel explosive formulations have highlighted the need for a modernized approach to traditional wedge tests. We present our concept of an impact-loaded wedge test which uses a gas gun, a wedge-shaped explosive sample and the line-imaging ORVIS (Optically Recording Velocity Interferometer System) diagnostic. The ORVIS optical configuration is modified from the standard configuration to project the laser line onto the inclined surface of the wedge-shaped sample where the return light is collected with a streak camera. Initial data of shock breakout in inert samples are presented.

Cooper, Marcia A.; Trott, Wayne M.

2012-03-01

422

Impact of time-dependency on long-term material testing and modeling of polyethylene  

NASA Astrophysics Data System (ADS)

Ultra-high molecular weight polyethylene (UHMWPE) has an important role in orthopaedic implants because of its favorable properties as an articulating surface. UHMWPE component testing often focuses on measuring the long-term fatigue or wear response of the material that could be realized during many years of use. However, the impact of time-dependent properties of UHMWPE on such tests is not well characterized. In particular, altering the frequency of loading and allowing for material creep or relaxation can significantly alter the stress/strain state of the material, and therefore affect long-term mechanical properties (e.g. wear, fatigue) that are dependent on the constitutive state. The goal of this work is to use advanced, validated material modeling of UHMPWE that incorporates time-dependent properties to explore the effects of frequency and rest time on the mechanical response of UHMWPE.

Bischoff, Jeffrey E.

2008-09-01

423

Assessment of impact damage in Kevlar{reg_sign}-epoxy, filament-wound spherical test specimens by acoustic emission techniques  

Microsoft Academic Search

The results of a study of the acoustic emission (AE) behavior of impact-damaged, spherical, composite test specimens subjected to thermal cycling and biaxial mechanical loading are presented. Seven Kevlar{reg_sign}-epoxy, filament-wound, spherical composite test specimens were subjected to different levels of impact damage. The seven specimens were a subset of a group of 77 specimens made with simulated fabrication-induced flaws. The

J. W. Whittaker; W. D. Brosey; M. A. Hamstad

1996-01-01

424

Genetic testing for Lynch syndrome in the first year of colorectal cancer: a review of the psychological impact  

Microsoft Academic Search

An increasing number of patients with colorectal cancer (CRC) receive genetic counselling within 1 year after diagnosis. Little\\u000a is known whether specific subgroups are more vulnerable for genetic testing related distress. A literature review was conducted\\u000a to identify the psychological impact of CRC in the first year, and the additional impact of genetic testing. The electronic\\u000a databases of PubMed, PsychInfo, Embase

Karin M. Landsbergen; Judith B. Prins; Han G. Brunner; Floris W. Kraaimaat; Nicoline Hoogerbrugge

2009-01-01

425

How Well Does the Latest Anthropomorphic Test Device Mimic Human Impact Responses?  

NASA Technical Reports Server (NTRS)

One of the goals of the NASA Occupant Protection Group is to understand the human tolerance to dynamic loading. This knowledge has to come through indirect approaches such as existing human response databases, anthropometric test devices (ATD), animal testing, post-mortem human subjects, and models. This study investigated the biofidelity of the National Highway Traffic Safety Administration's ATD named the THOR (test device for human occupant restraint). If THOR responds comparably to humans, then it could potentially be used as a human surrogate to help validate space vehicle requirements for occupant protection. The THOR responses to frontal and spinal impacts (ranging from 8 to 12 G with rise times of 40, 70, and 100 ms) were measured and compared to human volunteer responses (95 trials in frontal and 58 in spinal) previously collected by the U. S. Air Force on the same horizontal impact accelerator. The impact acceleration profiles tested are within the expected range of multi-purpose crew vehicle (MPCV) landing dynamics. A correlation score was calculated for each THOR to human comparison using CORA (CORrelation and Analysis) software. A two-parameter beta distribution model fit was obtained for each dependent variable using maximum likelihood estimation. For frontal impacts, the THOR head x-acceleration peak response correlated with the human response at 8 and 10-G 100 ms but not 10-G 70 ms. The phase lagged the human response. Head z-acceleration was not correlated. Chest x-acceleration was in phase, had a higher peak response, and was well correlated with lighter subjects (Cora = 0.8 for 46 kg vs. Cora = 0.4 for 126 kg). Head x-displacement had a leading phase. Several subjects responded with the same peak displacement but the mean of the group was lower. The shoulder x-displacement was in phase but had higher peaks than the human response. For spinal impacts, the THOR head x-acceleration was not well correlated. Head and chest z-acceleration was in phase but had a higher peak response. Chest z-acceleration was highly correlated with heavier subjects at lower G pulses (Cora = 0.86 for 125 kg at 8 G). The human response was variable in shoulder z-displacement but the THOR was in phase and was comparable to the mean peak response. Head xand z-displacement was in phase but had higher peaks. Seat pan forces were well correlated, were in phase, but had a larger peak response than most subjects. The THOR does not respond to frontal and spinal impacts exactly the same way that a human does. Some responses are well matched and others are not. Understanding the strengths and weaknesses of this ATD is an important first step in determining its usefulness in occupant protection at NASA

Newby, N.; Somers, J. T.; Caldwell, E.; Gernhardt, M.

2014-01-01

426

Impact of genetic counseling and testing on colorectal cancer screening behavior.  

PubMed

One goal of cancer genetic counseling is to improve early detection and prevention of cancers by identifying individuals at risk and providing screening recommendations. This study determined the impact of genetic counseling and testing on patient's post-genetic risk assessment colorectal cancer screening behaviors. Follow-up data from patients seen August, 1996, through May, 1998, at the Johns Hopkins Cancer Risk Assessment Clinic were analyzed. Eligible patients included those without cancer who were due for a colon examination by the time of follow-up, based on recommendations given during genetic risk assessment (GRA). We analyzed the role of gender, age, time since GRA, prior screening, genetic testing decision, mutation status, and post-GRA screening. Of 65 patients evaluated, 50 (76.9%) had undergone at least one endoscopic colon exam prior to visiting the Cancer Risk Assessment Clinic. At the time of GRA, 37 of 65 (56.9%) were overdue for a colon exam and at the time of follow-up, 15/65 (23.1%) were past due (p < 0.001). Patients with mutation-positive genetic tests were more likely to adhere to screening guidelines than those with negative gene tests (100% vs. 40.5%, p = 0.05). Genetic counseling and testing increases overall patient adherence with recommended colon screening, especially for those with positive genetic test results. However, patients with negative results may receive false reassurance about cancer risks and fail to follow recommended screening. Emphasis should be placed on the importance of screening even when genetic test results are negative. PMID:12537654

Johnson, Karen A; Trimbath, Jill D; Petersen, Gloria M; Griffin, Constance A; Giardiello, Francis M

2002-01-01

427

Internally damped, self-arresting vertical drop-weight impact test apparatus  

NASA Technical Reports Server (NTRS)

A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Waters, Jr., William A. (Inventor); Stockum, Robert W. (Inventor); Walter, Manfred A. (Inventor)

1996-01-01

428

Internally damped, self-arresting vertical drop-weight impact test apparatus  

NASA Technical Reports Server (NTRS)

A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Waters, Jr., William A. (Inventor); Stockum, Robert W. (Inventor); Water, Manfred A. (Inventor)

1995-01-01

429

Testing agonist-induced platelet aggregation by the Impact-R [Cone and plate(let) analyzer (CPA)].  

PubMed

The Impact-R [Cone and plate(let) analyzer (CPA)] is useful to assess platelet adhesion in different diseases and to monitor antiplatelet therapy. The purpose of the present study was to adapt this system to test agonist-induced platelet aggregation. Blood samples were tested by light transmission platelet aggregometry (LTA), Impact-R regular test and Impact-R agonist-response test. In the latter, samples were pre-incubated for 1 min with an agonist leading to platelet activation, micro-aggregates formation and reduced adhesion. Impact-R regular test of ten healthy volunteers demonstrated platelet adhesion (surface coverage, SC) of 11.2 +/- 2.6% while LTA induced by ADP, ristocetin, epinephrine, collagen and arachidonic acid (AA) yielded maximal aggregation (81% to 93%). In the Impact-R agonist-response test, SC was reduced to 2.2 +/- 1.0%, 1.2 +/- 0.9%, 2.3 +/- 1.0%, 2.2 +/- 0.8% and 2.4 +/- 0.4%, respectively. Prostaglandin E(1) treatment weakened SC reduction in response to ADP and epinephrine (SC of 8.8 +/- 1.8% and 9.5 +/- 2.0%, respectively). Inhibition of P2Y(12) receptor with 2MeSAMP resulted in a dose-dependent decrease in maximal aggregation in the ADP-induced test, which inversely correlated to SC in the Impact-R ADP-response test. The Impact-R agonist-response tests detected aggregation defects in patients with storage pool disease, severe von Willebrand disease and epinephrine response deficiency, and may be useful to assess the effect of different agonists on platelet aggregation. PMID:18925512

Shenkman, B; Einav, Y; Salomon, O; Varon, D; Savion, N

2008-09-01

430

Calibration of an item pool for assessing the burden of headaches: An application of item response theory to the Headache Impact Test (HIT™)  

Microsoft Academic Search

Background: Measurement of headache impact is important in clinical trials, case detection, and the clinical monitoring of patients. Computerized adaptive testing (CAT) of headache impact has potential advantages over traditional fixed-length tests in terms of precision, relevance, real-time quality control and flexibility. Objective: To develop an item pool that can be used for a computerized adaptive test of headache impact.

Jakob B. Bjorner; Mark Kosinski; John E. Ware Jr

2003-01-01

431

Explicit Finite Element Modeling of Multilayer Composite Fabric for Gas Turbine Engine Containment Systems. Part 2; Ballistic Impact Testing  

NASA Technical Reports Server (NTRS)

Under the Federal Aviation Administration's Airworthiness Assurance Center of Excellence and the Aircraft Catastrophic Failure Prevention Program, National Aeronautics and Space Administration Glenn Research Center collaborated with Arizona State University, Honeywell Engines, Systems and Services, and SRI International to develop improved computational models for designing fabric-based engine containment systems. In the study described in this report, ballistic impact tests were conducted on layered dry fabric rings to provide impact response data for calibrating and verifying the improved numerical models. This report provides data on projectile velocity, impact and residual energy, and fabric deformation for a number of different test conditions.

Pereira, J. M.; Revilock, D. M.

2004-01-01

432

Simulating the Response of a Composite Honeycomb Energy Absorber. Part 2; Full-Scale Impact Testing  

NASA Technical Reports Server (NTRS)

NASA has sponsored research to evaluate an externally deployable composite honeycomb designed to attenuate loads in the event of a helicopter crash. The concept, designated the Deployable Energy Absorber (DEA), is an expandable Kevlar(Registered TradeMark) honeycomb. The DEA has a flexible hinge that allows the honeycomb to be stowed collapsed until needed during an emergency. Evaluation of the DEA began with material characterization of the Kevlar(Registered TradeMark)-129 fabric/epoxy, and ended with a full-scale crash test of a retrofitted MD-500 helicopter. During each evaluation phase, finite element models of the test articles were developed and simulations were performed using the dynamic finite element code, LS-DYNA(Registered TradeMark). The paper will focus on simulations of two full-scale impact tests involving the DEA, a mass-simulator and a full-scale crash of an instrumented MD-500 helicopter. Isotropic (MAT24) and composite (MAT58) material models, which were assigned to DEA shell elements, were compared. Based on simulations results, the MAT58 model showed better agreement with test.

Fasanella, Edwin L.; Annett, Martin S.; Jackson, Karen E.; Polanco, Michael A.

2012-01-01

433

Investigation of Steven Impact Test Using a Transportation Hook Projectile with Gauged Experiments and 3D Modeling  

NASA Astrophysics Data System (ADS)

The Steven Impact Test and associated modeling offer valuable practical predictions for evaluating numerous safety scenarios involving low velocity impact of energetic materials by different projectile geometries. One such scenario is the impact of energetic material by a transportation hook during shipping, which offers complexity because of the irregular hook projectile shape. Experiments were performed using gauged Steven Test targets with PBX9404 impacted by a transportation hook projectile to compliment previous non-gauged experiments that established an impact threshold of approximately 69 m/s. Modeling of these experiments was performed with LS-DYNA code using an Ignition and Growth reaction criteria with a friction term. Comparison of the experiment to the model shows reasonable agreement with some details requiring more attention. The experimental results (including carbon resistor gauge records), model calculations, and a discussion of the dominant reaction mechanisms in light of comparisons between experiment and model will be presented.

Vandersall, Kevin S.; Murty, Susarla S.; Chidester, Steven K.; Forbes, Jerry W.; Garcia, Frank; Greenwood, Daniel W.; Tarver, Craig M.

2004-07-01

434

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

National Technical Information Service (NTIS)

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, con...

A. K. Sareen C. E. Sparks E. L. Fasanella K. H. Lyle

2004-01-01

435

Prostate cancer in Austria: impact of prostate-specific antigen test on incidence and mortality.  

PubMed

The aim of the study was to assess the impact of prostate-specific antigen (PSA) testing on prostate cancer mortality in Austria. A join-point regression model and permutation tests were used to identify changes in the slope of age-specific trends respectively calculating the annual percentage change (APC). Age-adjusted incidence increased (P < 0.01) between 1983 and 1997 by 79% from 52.2 to 93.6 cases per 100 000 men/year. Incidence in localized/regional stage disease increased in all ages by 143% from 25.7 to 62.4 cases per 100 000 men/year. Incidence in distant disease decreased (P < 0.01) between 1983 and 1997 in all ages by 38% from 9.5 to 5.9 cases per 100 000 men/year. Incidence in unstaged disease increased (P < 0.01) between 1983 and 1997 in all ages by 300% from 4.5 to 18 cases per 100 000 men/year. Age-adjusted mortality increased (P < 0.05) by 13% from 26.8 in 1983 to 30.3 deaths per 100 000 men/year in 1999. No significant changes of trends in mortality rates were detected in the age groups 50-59 years. In the age group 70-79 years the trend changed (P < 0.05) direction in 1991 and in 1994; 1983 through 1991 APC = 3.52 (95% CI 1.37, 5.72), 1991 through 1994 APC = -10.27 (95% CI -26.20, 9.1) and 1994 through 1999 APC = -0.25 (95% CI -4.55, 4.24). PSA testing increased incidence but no impact on mortality in the target population can be observed so far. PMID:11711757

Vutuc, C; Waldhoer, T; Madersbacher, S; Micksche, M; Haidinger, G

2001-10-01

436

Application of a PVDF-based stress gauge in determining dynamic stress-strain curves of concrete under impact testing  

NASA Astrophysics Data System (ADS)

Polyvinylidene fluoride (PVDF) piezoelectric material has been successfully applied in many engineering fields and scientific research. However, it has rarely been used for direct measurement of concrete stresses under impact loading. In this paper, a new PVDF-based stress gauge was developed to measure concrete stresses under impact loading. Calibrated on a split Hopkinson pressure bar (SHPB) with a simple measurement circuit of resistance strain gauges, the PVDF gauge was then used to establish dynamic stress-strain curves of concrete cylinders from a series of axial impact testing on a drop-hammer test facility. Test results show that the stress curves measured by the PVDF-based stress gauges are more stable and cleaner than that of the stress curves calculated with the impact force measured from a load cell.

Meng, Yi; Yi, Weijian

2011-06-01

437

The performance assessment impacts of disposal of high-moisture, low-level radioactive waste at the Nevada Test Site  

SciTech Connect

A panel of independent scientists was convened by the Department of Energy to assess the performance impacts of disposal of low-level radioactive waste from the Fernald Environmental Management Project. This waste stream was involved in a transportation incident in December 1997. A resulting outgrowth of investigations of the transportation incident was the recognition that the waste was transported and disposed in stress-fractured metal boxes and some of the waste contained excess moisture (high volumetric water contents). The panel was charged with determining whether disposal of this waste in the Area 5 radioactive waste management site on the Nevada Test Site has impacted the conclusions of the completed performance assessment. Three questions were developed by the panel to assess performance impacts: (1) the performance impacts of reduced container integrity, (2) the impact of reduced container integrity on subsidence of waste in the disposal pits and (3) the performance impacts of excess moisture. No performance or subsidence impacts were noted from disposal of the Fernald waste. The impacts of excess moisture were assessed through simulation modeling of the movement of moisture in the vadose zone assuming high water contents (wet waste) for different percentages of the waste inventory. No performance impacts were noted for either the base-case scenario (ambient conditions) or a scenario involving subsidence and flooding of the waste cells. The absence of performance impacts results form the extreme conservatism used in the Area 5-performance assessment and the robust nature of the disposal site.

Crowe, B.M.; Hansen, W. [Los Alamos National Lab., NM (United States); Hechnova, A. [Univ. of Nevada, Las Vegas, NV (United States). Harry Reid Center of Environmental Studies; Jacobson, R. [Desert Research Inst., Reno, NV (United States); Voss, C. [Golder Associates, Inc. (United States); Waters, R. [Sandia National Labs., Albuquerque, NM (United States); Sully, M.; Levitt, D. [Bechtel Nevada, Las Vegas, NV (United States)

1999-03-01

438

Fracture Behavior of Ultra-Low-Carbon Steel Plate and Heat-Affected-Zone.  

National Technical Information Service (NTIS)

This report describes research carried out to investigate the fracture of ultra-low-carbon bainitic steels. Eight materials have been evaluated using notched-bar bend tests, tensile strength tests and Charpy V-notch impact tests, which were performed over...

M. G. Vassilaros

1990-01-01

439

Clarifying the Policy Contexts of Statewide Testing and Accountability and Their Impact on Secondary-Level Students with Disabilities  

Microsoft Academic Search

Current testing and accountability systems have been molded by a variety of political and other pressures, resulting in a flurry of policymaking both at the federal level and in the states. Understanding the multiple levels of the policymaking process and the impact of local implementation on testing and accountability helps identify points of influence and ways to align local district

Jane L. Krentz; Ann T. Clapper; Martha L. Thurlow; David R. Johnson

2001-01-01

440

The impacts of statewide benchmark reading tests on the motivations to read of students in grades 4--8  

Microsoft Academic Search

The purpose of this study was to examine the perspectives of fourth through eighth grade students related to their motivations to read and the impacts that standardized benchmark reading tests have on their reading motivations. Much debate among educational experts and politicians has focused on the standardized testing regimens required by the No Child Left Behind Act (NCLB). This study

Richard Charles Carriveau

2006-01-01

441

46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.  

Code of Federal Regulations, 2010 CFR

...properties for service of 0 ðF and below. 54.05-20 Section 54.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of 0 °F...

2009-10-01

442

46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.  

Code of Federal Regulations, 2010 CFR

...properties for service of 0 ðF and below. 54.05-20 Section 54.05-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of 0 °F...

2010-10-01

443

Impact of Extremely Low Frequency Electromagnetic Fields on Soil Arthropods. Ongoing Studies at the Project Sanguine Wisconsin Test Facility, 1973.  

National Technical Information Service (NTIS)

Possible long-term Sanguine impact on soil arthropods was studied in nine test plots and six control plots. Comparisons of test and control populations of mites and Collembola include statistical treatment of within-year and between-year numbers, predator...

B. Greenberg N. Ash

1974-01-01

444

Evaluation of the Fatigue Behavior of Aluminide Coating Steel Substrate Compounds by Means of the Impact Testing Method  

Microsoft Academic Search

The impact testing is an efficient experimental method that enables the quantitative and qualitative evaluation of the fatigue resistance of mono- and multilayer coatings deposited on various substrates, which was not possible with the common testing methods previously available. In this article the experimental assessment of the fatigue resistance of aluminide slurry coatings working under cyclic loading conditions by means

K. G. Anthymidis; C. David; D. N. Tsipas

2011-01-01

445

On the Modeling of Electric Railway Lines for the Assessment of Infrastructure Impact in Radiated Emission Tests of Rolling Stock  

Microsoft Academic Search

In this paper, we address the problem of testing radiated emissions generated by rolling stock, when carried out on actual railway sites, as prescribed by the standard EN 50121. The idea of assessing infrastructure impact on test results is presented here by means of an electromagnetic model of railway sites. In the first part, modeling tools are introduced together with

Andrea Cozza; Bernard DÉmoulin

2008-01-01

446

Urineschool: A Study of the Impact of the Earls Decision on High School Random Drug Testing Policies.  

ERIC Educational Resources Information Center

Examines impact of Supreme Court's 2002 decision in "Board of Education v. Earls" on high school random drug-testing policies and practices. Court held that random drug-testing policy at Tecumseh, Oklahoma, school district did not violate students' Fourth Amendment right against unreasonable searches. (Contains 46 references.) (PKP)

Conlon, Cynthia Kelly

2003-01-01

447

Quantification of constant stiffness force-shortening model parameters for vehicles tested under United States side impact protocols  

Microsoft Academic Search

This study presents a methodology for deriving all coefficients of the constant stiffness force-shortening model for the sides of vehicles tested under the United States Federal Motor Vehicle Safety Standard 214 dynamic and high-speed lateral New Car Assessment Program tests. The method utilizes the a priori known moving deformable barrier configuration and velocity vector at impact as a constraint for

J. Singh; J. Perry

2005-01-01

448

Simulation Numerique d'Essais d'Impact et Comparaison de Lois de Comportement (Numerical Simulation of Impact Tests and Comparison of Behavior Laws).  

National Technical Information Service (NTIS)

A titanium alloy and two steels were impact tested. Johnson-Cook, Lindholn, and Bodner-Partom viscoplastic constitutive equations were tried as models using a Hemp code. The material constants are determined for each material on the results of Hopkinson b...

D. Bois A. Grave

1985-01-01

449

Flight test experience and controlled impact of a remotely piloted jet transport aircraft  

NASA Technical Reports Server (NTRS)

The Dryden Flight Research Center Facility of NASA Ames Research Center (Ames-Dryden) and the FAA conducted the controlled impact demonstration (CID) program using a large, four-engine, remotely piloted jet transport airplane. Closed-loop primary flight was controlled through the existing onboard PB-20D autopilot which had been modified for the CID program. Uplink commands were sent from a ground-based cockpit and digital computer in conjunction with an up-down telemetry link. These uplink commands were received aboard the airplane and transferred through uplink interface systems to the modified PB-20D autopilot. Both proportional and discrete commands were produced by the ground system. 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