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EFFECTS OF MATERIALS STRENGTH ON STRONGLY-SHOCKED NONENERGETIC MATERIALS

Description: The role of materials strength in changing the shock dynamics in strongly-shocked nonenergetic materials is still a matter of investigation because materials strength properties become convoluted with other materials properties and the shock strength. The regime under consideration here is one in which the material in question is shocked strongly enough to be treated as a fluid, but not strongly enough to be treated as a simple fluid. The present work takes a case-study approach in which two models of the constitutive properties of the complex fluid are applied to shock instability for two different polymeric materials. The intent here is to obtain some measure of the sensitivity of the model predictions to variations in the complex fluid constitutive properties. The linear time-regime in a Richtmyer-Meshkov instability is modeled with the viscosity dependence of Mikaelian and the nonlinear time-regime is modeled with an aerodynamic viscous-drag model. Each combination of materials and models will be examined as a function of shock strength, Atwood number, and variation in materials constitutive properties. Although the these models are NOT the most advanced, they are useful for illustrating orders of magnitude.
Date: January 1, 2001
Creator: Valone, S. M. (Steven M.)
Partner: UNT Libraries Government Documents Department

ALE advantage in hypervelocity impact calculations

Description: The ALE3D code is used to model experiments relevant to hypervelocity impact lethality, carried out in the 4-5 km/s velocity range. The code is run in the Eulerian and ALE modes. Zoning in the calculations is refined beyond the level found in most lethality calculations, but still short of convergence. The level of zoning refinement that produces equivalent results in uniformly zoned Eulerian calculations and ALE ones utilizing specialized zoning, weighting and relaxation techniques is established. It takes 11 times fewer zones and about 60% as many cycles when ALE capabilities are used. Calculations are compared to experimental results.
Date: October 1, 1998
Creator: Gerassimenko, M. & Rathkopf, J.
Partner: UNT Libraries Government Documents Department

Comet Shoemaker-Levy 9 fragment size estimates: How big was the parent body?

Description: The impact of Comet Shoemaker-Levy 9 on Jupiter in July, 1994, was the largest, most energetic impact event on a planet ever witnessed. Because it broke up during a close encounter with Jupiter in 1992, it was bright enough to be discovered more than a year prior to impact, allowing the scientific community an unprecedented opportunity to assess the effects such an event would have. Many excellent observations were made from Earth-based telescopes, the Hubble Space Telescope (HST) and the Galileo spacecraft en route to Jupiter. In this paper, these observations are used in conjunction with computational simulations performed with the CTH shock-physics hydrocode to determine the sizes of the fifteen fragments that made discernible impact features on the planet. To do this, CTH was equipped with a radiative ablation model and a post-processing radiative ray-trace capability that enabled light-flux predictions (often called the impact flash) for the viewing geometries of Galileo and ground-based observers. The five events recorded by Galileo were calibrated to give fragment size estimates. Compared against ground-based and HST observations, these estimates were extended using a least-squares analysis to assess the impacts of the remaining ten fragments. Some of the largest impacts (L, G and K) were greater that 1 km in diameter but the density of the fragments was low, about 0.25 g/cm{sup 3}. The volume of the combined fifteen fragments would make a sphere 1.8 km in diameter. Assuming a pre-breakup density of 0.5 g/cm{sup 3}, the parent body of Shoemaker-Levy 9 had a probable diameter of 1.4 km. The total kinetic energy of all the impacts was equivalent to the explosive yield of 300 Gigatons of TNT.
Date: December 1995
Creator: Crawford, D. A.
Partner: UNT Libraries Government Documents Department

Enhanced diffusion in shock activated Be-Al interfaces

Description: Enhanced diffusion of aluminum in shock activated beryllium has been observed. Cylindrical samples of aluminum coated beryllium rods were axisymetrically loaded up to 40 GPa and a total residual strain of up to 6.7%. The defect microstructure produced by both the shock wave and strain enabled the transport of aluminum in beryllium to exceed its equilibrium solid state saturation. This {open_quotes}super saturated{close_quotes} aluminum, upon heating exsolves out at relatively low temperatures and forms very strong interfaces with pressure mated components.
Date: May 1, 1997
Creator: Staudhammer, K.P.
Partner: UNT Libraries Government Documents Department

A Study of the Conservatism of Resonant Shock Test Fixtures

Description: Portions of a series of end-of-life tests are described for a Sandia National Li~boratories- designed space-based sensor that utilizes a mercury-cadmium-telluride focal plane array. Variations in background intensity are consistent with the hypothesis that seasonal variations in solar position cause changes in the pattern of shadows falling across the compartment containing the optical elements, filter-band components, and focal plane array. When the sensor compartment is most fully illuminated by the sun, background intensities are large and their standard deviations tend to be large. During the winter season, when the compartment is most fully shadowed by surrounding structure, backgrounci intensities are small and standard deviations tend to be small. Details in the surrounding structure are speculated to produce transient shadows that complicate background intensifies as a function of time or of sensor position in orbit. KEYwoRDs Noise measurements, background intensity, focal plane array, mercury-cadmium-telluride.
Date: December 3, 1998
Creator: Cap, J.S.
Partner: UNT Libraries Government Documents Department

Numerical simulations of glass impacts using smooth particle hydrodynamics

Description: As part of a program to develop advanced hydrocode design tools, we have implemented a brittle fracture model for glass into the SPHINX smooth particle hydrodynamics code. We have evaluated this model and the code by predicting data from one-dimensional flyer plate impacts into glass. Since fractured glass properties, which are needed in the model, are not available, we did sensitivity studies of these properties, as well as sensitivity studies to determine the number of particles needed in the calculations. The numerical results are in good agreement with the data.
Date: July 1, 1995
Creator: Mandell, D.A. & Wingate, C.A.
Partner: UNT Libraries Government Documents Department

EFFECT OF IMPACT LIMITER MATERIAL DEGRATION ON STRUCTURAL INTEGRITY OF 9975 PACKAGE SUBJECTED TO TWO FORKLIFT TRUCK IMPACT

Description: This paper evaluates the effect of the impact limiter material degradation on the structural integrity of the 9975 package containment vessel during a postulated accident event of forklift truck collision. The analytical results show that the primary and secondary containment vessels remain structurally intact for Celotex material degraded to 20% of the baseline value.
Date: July 9, 2007
Creator: Wu, T
Partner: UNT Libraries Government Documents Department

Adjustable Shock Test Sled for Haversine Pulses at 250 fps

Description: New test requirements were developed by Sandia National Laboratory to simulate a regime of shock testing not previously performed at the Kansas City Plant operated by Honeywell Federal Manufacturing & Technologies. These environments were unique in that they involved amplitude of shock >1000g with relatively long pulse durations (greater 5 ms but less than 10 ms) and involved velocity changes up to 235 ft/sec. Ten months were available to develop, design, manufacture and prove-in this new capability. We designed a new shock sled to deliver this new family of shock environments in a laboratory test. The performance range of the new sled includes five specific shocks (1000 g – 8 ms, 1300 - 6 ms, 1500 g – 5.4 ms, 1950 g – 6 ms, 2250 g – 5.4 ms; all haversine shaped), and it also incorporates adjustability to accommodate new shocks within this range. These shock environments result in velocity changes ranging from 160 fps to 250 fps. The test sled accommodates test articles weighing up to 20 lbs and measuring up to 10” along any axis.
Date: May 5, 2008
Creator: Hartwig, Troy; Hower, Brent & Seaholm, Aaron
Partner: UNT Libraries Government Documents Department

MHD modeling of atlas experiments to study transverse shear interface interactions

Description: The transverse shear established at the interface of two solids moving at differential velocities on the order of the sound speed is being studied in experiments on the ATLAS capacitor bank at Los Alamos. The ATLAS bank has finished certification tests and has demonstrated peak currents of 27.5 MA into an inductive load with a risetime of 5 microseconds. One- and two-dimensional MHD calculations have been performed in support of these 'friction-like' ATLAS experiments. Current flowing along the outer surface of a thick aluminum liner, 10 mm thick at impact with the interaction target, accelerates the liner to velocities of {approx}1.0-1.5 km/s. This cylindrically imploding liner impacts a target assembly composed of alternating disks of high- and low-density materials. Different shock speeds in the two materials leads to a differential velocity along the interface. Shock heating, elastic-plastic flow, and stress transport are included in the calculations. Material strength properties are modeled with a Steinburg-Guinan treatment in these first studies. Various design configurations for the ATLAS experiments are now being considered and will be presented.
Date: January 1, 2001
Creator: Cochran, F. L. (Frederick L.); Hammerberg, J. E. (James E.); Keinigs, R. K. (Rhonald K.) & Faehl, R. J. (Rickey J.)
Partner: UNT Libraries Government Documents Department

AEC SYMPOSIUM ON PACKAGING AND REGULATORY STANDARDS FOR SHIPPING RADIOACTIVE MATERIALS, HELD IN GERMANTOWN, MARYLAND , DECEMBER 3-5, 1962

Description: A total of twenty papers and one roundtable discussion were presented. Separate abstracts were prepared for eighteen of the papers. The papers for which no abstracts were prepared are concerned with impact energy sorption by large shipping casks, design of a Pu and enriched U shipping container, and the roundtable discussion on regulatory standards. (J.R.D.)
Date: December 1, 1962
Partner: UNT Libraries Government Documents Department

PRESSURE VESSEL FABRICATION USING T-1 STEEL

Description: The fabrication of pressure vessels using C-l steel is described. The welding, welding electrodes, explosionbulge test, and impact and fatigue properties for the pressure vessel are given. (W.L.H.)
Date: November 14, 1957
Creator: Franco-Ferreira, E.A.
Partner: UNT Libraries Government Documents Department

IMPACT EFFECT OF FRAGMENTS STRIKING STRUCTURAL ELEMENTS

Description: Equations were developed which permit a designer to evaluate the impact effect of a missile striking a structural element at high velocity. Examples of the use of the equations in calculations and comparisons of the relative effect of penetration on the equivalent static design load are included. Application to calculations of structural containnent for nuclear power plants is discussed briefly. (C. H.)
Date: January 1, 1957
Creator: Williamson, R.A. & Alvy, R.R.
Partner: UNT Libraries Government Documents Department

Thermal Radiative Heat Transfer to Space From a Body Enclosed by a Semitransparent Body

Description: Bumpers were proposed for protecting space radiator systems from penetration by meteoroids. The development of equations to determine the thermal energy dissipation to space by a hot body completely enclosed by a second body is presented. The particular case of heat dissipation from space radiators enclosed within the bumpers is considered, and the criteria for selection of bumper materials for a minimum weight radiator system are discussed. (auth)
Date: May 1, 1960
Creator: Hefner, R. J.
Partner: UNT Libraries Government Documents Department

19 mm ballistic range: a potpourri of techniques and recipes

Description: The expansion of ballistic gun range facilities at LLL has introduced state-of-the-art diagnostic techniques to glovebox-enclosed ballistic guns systems. These enclosed ballistic ranges are designed for the study of one- dimensional shock phenomena in extremely toxic material such as plutonium. The extension of state-of-the-art phtographic and interferometric diagnostic systems to glovebox-enclosed gun systems introduces new design boundaries and performance criteria on optical and mechanical components. A technique for experimentally evaluating design proposals is illustrated, and several specific examples (such as, target alignment, collateral shrapnel damage, and soft recovery) are discussed. (auth)
Date: September 23, 1975
Creator: Carpluk, G.T.
Partner: UNT Libraries Government Documents Department

TERTIARY EFFECTS OF BLAST--DISPLACEMENT. Preliminary Report

Description: Measurements were made of the velocity and distance of translation of anthropomorphic dummies and equivalent spheres caused by blast winds. The primary technique for recording the movement of these ohjects was phototriangulation. The secondary technique (applicable to certain of the equivalent spheres) was to have the spheres impelled into missile traps. The resultant penetration provides a means for determining the velocity at the time of impact. Analysis of the results from both the primary and secondary techniques is expected to provide some of the irformation identified in the objective. (auth)
Date: September 1, 1957
Creator: Taborelli, R.V. & Bowen, I.G.
Partner: UNT Libraries Government Documents Department

SIMULATION OF SHOCK AND VIBRATION ENVIRONMENTS

Description: The purpose of simulation of shock and vibration environments is to produce in the tested item a process of damage which is related in some useful and known way to the damage which is expected from the service environment. An attempt is made to develop a clear picture of what constitutes realism in environmental simulation. (W.L.H.)
Date: February 1, 1958
Creator: Mains, R.M.
Partner: UNT Libraries Government Documents Department