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Results for “PENETRATION BALLISTICS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

In situ X-ray diffraction measurement of shock-wave-driven twinning and lattice dynamics

We report that pressure-driven shock waves in solid materials can cause extreme damage and deformation. Understanding this deformation and the associated defects that are created in the material is crucial in the study of a wide range of phenomena, including planetary formation and asteroid impact sites, the formation of interstellar dust clouds, ballistic penetrators, spacecraft shielding and ductility in high-performance ceramics. At the lattice level, the basic mechanisms of plastic deformation are twinning (whereby crystallites with a mirror-image lattice form) and slip (whereby lattice dislocations are generated and move), but determining which of these mechanisms is active during deformation is challenging. Experiments that characterized lattice defects have typically examined the microstructure of samples after deformation, and so are complicated by post-shock annealing and reverberations. In addition, measurements have been limited to relatively modest pressures (less than 100 gigapascals). In situ X-ray diffraction experiments can provide insights into the dynamic behaviour of materials, but have only recently been applied to plasticity during shock compression and have yet to provide detailed insight into competing deformation mechanisms. Here we present X-ray diffraction experiments with femtosecond resolution that capture in situ, lattice-level information on the microstructural processes that drive shock-wave-driven deformation. To demonstrate this method we shock-compress the body-centred-cubic material tantalum—an important material for high-energy-density physics owing to its high shock impedance and high X-ray opacity. Tantalum is also a material for which previous shock compression simulations and experiments have provided conflicting information about the dominant deformation mechanism. Our experiments reveal twinning and related lattice rotation occurring on the timescale of tens of picoseconds. In addition, despite the common association between twinning and strong shocks, we find a transition from twinning to dislocation-slip-dominated plasticity at high pressure (more than 150 gigapascals), a regime that recovery experiments cannot accurately access. Lastly, the techniques demonstrated here will be useful for studying shock waves and other high-strain-rate phenomena, as well as a broad range of processes induced by plasticity.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Subcritical turbulence spreading and avalanche birth

In confined plasmas, a localized fluctuation in a marginal or weakly damped region will propagate and generate an avalanche if it exceeds a threshold. In this letter, a new model for turbulence spreading based on subcritical instability in the turbulence intensity is introduced. We derive a quantitative threshold for spreading from a seed in a stable region, based on a competition between diffusion and nonlinear growth of the turbulence intensity. The model resolves issues with the established Fisher equation model for turbulence spreading, which is supercritical and cannot support the stationary coexistence of multiple turbulence levels. Implications for turbulence spreading are discussed, including the dynamics of ballistic penetration of turbulence into the stable zone. Finally, tests of the theory are suggested.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Plate Impact and Penetration at the Ballistic Launch Tube: Experiments

This report details the data collected from plate impact experiments performed at the Ballistics Launch Tube (BLT) in May 2019. The experiments consisted of 62 shots of copper projectiles (cylindrical and ogive) impacting 1/4", 1/2", and 3/4" aluminum plates at varying velocities. An additional 14 shots of copper cylinders on a 1" steel plate were fired at varying velocities as a Taylor anvil test. We recorded videos of the impact events and resulting fragmentation using a multi-view system of three high speed cameras. The purpose of these tests was to collect high quality data from the multi-view camera system and create digital representations of the deformed target, projectile and fragments. This data is intended to be used as validation data set for high fidelity simulation codes. This report covers the experimental setup, diagnostics, and collected data. Data processing and analysis are underway and will be discussed in a separate report.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2019

Constitutive Modeling of High-Temperature Flow Stress of Armor Steel in Ballistic Applications: A Comparative Study

Armox 500T is one of the armor grade steels extensively used as armor against bullet penetration in ballistic applications. In such applications, the material undergoes plastic deformation at large strain rates (10{sup 3} s{sup −1}) at temperatures of the order of 673-1373 K. In the present work, an attempt has been made to predict strain rate and temperature-dependent flow behavior of Armox 500T steel through physical-based model like modified Zerilli–Armstrong (M-ZA) and phenomenological-based models like Cowper Symonds (CS), modified Johnson–Cook (M-JC), Arrhenius (Arr.) and Khan–Huang–Liang (KHL) constitutive material model. Isothermal uniaxial compression tests at low strain rates (10{sup −3}-10{sup −1} s{sup −1}) and dynamic compression tests at high strain rates (600-3000 s{sup −1}) in the temperatures range of 673-1373 K have been carried out to determine constitutive material model parameters. In addition, an artificial neural network (ANN) model that works on multilayer perceptron (MLP) based back propagation neural network (BPNN) has also been developed. The results from all these models have been compared in terms of three statistical parameters namely correlation coefficient (R), mean absolute percent error (MAPE) and its standard deviation (Δ). The results revealed that M-JC model shows highest correlation coefficient and lowest average absolute error. Further, ANN model prediction has the highest accuracy with R = 0.999 and MAPE = 1.052.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration.

Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is nonexistent but necessary to protect the heart and lungs. In tests against ballistic projectiles, protective apparel is placed over ballistic clay and the projectiles are fired into the armor/clay target. The clay represents the human torso and its behind-armor, permanent deflection is the principal metric used to assess armor protection. Although this approach provides relative merit assessment of protection, it does not examine the behind-armor blunt trauma to crucial torso organs. We propose a modeling and simulation (M&S) capability for wound injury scenarios to the head, neck, and torso of the warfighter. We will use this toolset to investigate the consequences of, and mitigation against, blast exposure, blunt force impact, and ballistic projectile penetration leading to damage of critical organs comprising the central nervous, cardiovascular, and respiratory systems. We will leverage Sandia codes and our M&S expertise on traumatic brain injury to develop virtual anatomical models of the head, neck, and torso and the simulation methodology to capture the physics of wound mechanics. Specifically, we will investigate virtual wound injuries to the head, neck, and torso without and with protective armor to demonstrate the advantages of performing injury simulations for the development of body armor. The proposed toolset constitutes a significant advance over current methods by providing a virtual simulation capability to investigate wound injury and optimize armor design without the need for extensive field testing.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2025

WHA Sphere Impacting RHA Plate: Modeling Brittle Behavior in Metal Alloys

Brittle behavior of metal alloys is often critical to modeling ballistic impact and penetration. The ALEGRA multiphysics finite element software incorporates calibrated models for the equation of state, elasticity, yield stress, plasticity and fracture, but simulations do not always capture expected metal fracture. Here we report concerted efforts to do so for one important case where experiments clearly show shear fractures: a tungsten sphere impacting a steel plate at various angles. Our best simulations show fractures that are qualitatively similar to experiments, but there are significant differences in quantitative metrics. Specifically, velocities of tracers used to quantify simulated plug parameters consistently fall short of measured plug velocities. Also, simulated plugs break apart more than expected from experimental evidence. We attribute these shortfalls to the lack of an explicit shear fracture mechanism in the material models, leading to over-estimated resistance to plug formation and movement.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Wound Ballistics Modeling for Blast Loading Blunt Force Impact and Projectile Penetration

Light body armor development for the warfighter is based on trial-and-error testing of prototype designs against ballistic projectiles. Torso armor testing against blast is virtually nonexistent but necessary to ensure adequate protection against injury to the heart and lungs. In this report, we discuss the development of a high-fidelity human torso model, it's merging with the existing Sandia Human Head-Neck Model, and development of the modeling & simulation (M&S) capabilities necessary to simulate wound injury scenarios. Using the new Sandia Human Torso Model, we demonstrate the advantage of virtual simulation in the investigation of wound injury as it relates to the warfighter experience. We present the results of virtual simulations of blast loading and ballistic projectile impact to the tors o with and without notional protective armor. In this manner, we demonstrate the ad vantages of applying a modeling and simulation approach to the investigation of wound injury and relative merit assessments of protective body armor without the need for trial-and-error testing.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2018

Regularities of Plasma-Immersion Formation of Long-Pulse High-Intensity Titanium Ion Beams

The results of experimental investigations on plasma-immersion formation of ballistically focused beams of low-energy titanium ions with the pulse duration up to 30 μs are presented. The processes of neutralization of the space charge of high-intensity beams upon increasing the ion-current density by a few orders of magnitude during their focusing are addressed. The conditions of preliminary injection of the metal plasma, its parameters, the formation of the beam plasma during residual-gas ionization and secondary and thermionic emissions are shown to be of critical importance for an effective transport of these beams in the equi-potential drift space. It is demonstrated that the use of a disc electrode, preventing the macroparticles from penetrating the region of the ballistic beam focusing, increases the efficiency of long-pulse titanium ion beam transport and simultaneously reduces the probability of instability development.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2018

Experimental Testing and Numerical Modeling of Ballistic Impact on S-2 Glass/SC 15 Composites

Here, the work presented in this paper details both an experimental program and an associated numerical modeling effort to characterize and predict the ballistic response of S-2 glass/SC15 epoxy composite panels. The experimental program consisted of ¼ inch diameter soft carbon steel spheres impacting ¼ and ½ inch thick flat composite panels at velocities ranging from 220 to 1570 m/s. High speed cameras were used to capture the impact event and resulting residual velocity of the spheres for each test configuration. After testing, each panel was inspected both visually and with ultrasonic C-scan techniques to determine the extent and depth of damage imparted on the panel by the impactor. The numerical modeling efforts utilized the anisotropic multi-constituent composite model (MCM) within the CTH shock physics hydrocode. The MCM model allows for evaluation of damage at the constituent level through continuum averaged stress and strain fields. The model also accounts for the inherent coupling of the equation of state and strength response that occurs in anisotropic composite materials. Finally, the simulation results are compared against the experimentally measured residual velocity as a quantitative metric and against the measured damage extent and patterns as a qualitative metric. The comparisons show good agreement in residual velocity and damage extent.

36 MATERIALS SCIENCE↗
DOE OSTI2017

ASPHERICITY, INTERACTION, AND DUST IN THE TYPE II-P/II-L SUPERNOVA 2013EJ IN MESSIER 74

SN 2013ej is a well-studied core-collapse supernova (SN) that stemmed from a directly identified red supergiant (RSG) progenitor in galaxy M74. The source exhibits signs of substantial geometric asphericity, X-rays from persistent interaction with circumstellar material (CSM), thermal emission from warm dust, and a light curve that appears intermediate between supernovae of Types II-P and II-L. The proximity of this source motivates a close inspection of these physical characteristics and their potential interconnection. We present multiepoch spectropolarimetry of SN 2013ej during the first 107 days and deep optical spectroscopy and ultraviolet through infrared photometry past ∼800 days. SN 2013ej exhibits the strongest and most persistent continuum and line polarization ever observed for a SN of its class during the recombination phase. Modeling indicates that the data are consistent with an oblate ellipsoidal photosphere, viewed nearly edge-on and probably augmented by optical scattering from circumstellar dust. We suggest that interaction with an equatorial distribution of CSM, perhaps the result of binary evolution, is responsible for generating the photospheric asphericity. Relatedly, our late-time optical imaging and spectroscopy show that asymmetric CSM interaction is ongoing, and the morphology of broad H α emission from shock-excited ejecta provides additional evidence that the geometry of the interaction region is ellipsoidal. Alternatively, a prolate ellipsoidal geometry from an intrinsically bipolar explosion is also a plausible interpretation of the data but would probably require a ballistic jet of radioactive material capable of penetrating the hydrogen envelope early in the recombination phase. Finally, our latest space-based optical imaging confirms that the late interaction-powered light curve dropped below the stellar progenitor level, confirming the RSG star’s association with the explosion.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Numerical Modeling of the Effects of Coating Plates on Terminal Ballistic Performance

This report deals with the development and evaluation of a numerical model to examine applied coating to a metal substrate subjected to a ballistic impact. The numerical model will be used to examine the benefit of the coating in resisting penetration due to the impact. For a detailed examination the Retch-Ipson curve is used as a metric. The numerical data is plotted and then fit to the Retch-Ipson curve and error calculations are used to compare the difference between the numerical output and the experimental data. This initial study is an examination of a few shortcomings of the standard material models used, and demonstrate the future work that is needed to understand the ballistic behavior of materials.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Small Penetrator Instrument Concept for the Advancement of Lunar Surface Science

Fundamental scientific objectives concerning the surface and subsurface material and dynamics of the Moon are the drivers for the use and advancement of penetrators, which emplace a suite of scientific instruments by impact into a planetary surface, typically at velocities of dozens to hundreds of meters per second. Small lunar penetrators are poised to become a valuable new tool for lunar science and exploration during the next decade. These low-cost ballistic probes can be deployed in large numbers from orbit, or from descending robotic or crewed vehicles, in order to explore and characterize the diversity of extreme lunar shallow subsurface environments. In this paper, we describe the general overview of penetrator objectives, potential instrumentation, and how these would benefit the advancement of lunar science at various extreme environments.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

Dynamic effects of interaction of composite projectiles with targets

The process of high-speed impact of projectiles against targets of finite thickness is experimentally investigated. Medium-hard steel plates are used as targets. The objective of this research is to carry out a comparative analysis of dynamic effects of interaction of various types of projectiles with targets, such as characteristics of destruction of the target, the state of the projectile behind the target, and particularities of the after-penetration stream of fragments after the target has been pierced. The projectiles are made of composites on the basis of tungsten carbide obtained by caking and the SHS-technology. To compare effectiveness of composite projectiles steel projectiles are used. Their effectiveness was estimated in terms of the ballistic limit. High density projectiles obtained by means of the SHS-technology are shown to produce results comparable in terms of the ballistic limit with high-strength projectiles that contain tungsten received by caking.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Crashworthiness Models for Automotive Batteries

Safety is a key element of any device designed to store energy, particularly of electrochemical batteries, which convert energy of chemical reactions to electrical energy. Safety considerations are especially important when applied to large automotive batteries designed for propulsion of electric vehicles (EV). The high amount of energy stored in EV battery packs translates to higher probability of fire in case of severe deformation of battery compartment due to automotive crash or impact caused by road debris. While such demand for safety has resulted in heavier protection of battery enclosure, the mechanisms leading to internal short circuit due to deformation of the battery are not well understood even on the level of a single electrochemical cell. Moreover, not all internal shorts result in thermal runaway, and thus a criterion for catastrophic failure needs to be developed. This report summarizes the effort to pinpoint the critical deformation necessary to trigger a short via experimental study on large format automotive Li-ion cells subjected to large deformations as those occurring in deformation of battery module or pack. Mechanical properties of cell components were determined via experimental testing and served as input for constitutive models of Finite Element (FE) analysis. It has been rationalized that long-range stress fields occurring in spherical indentation of battery modules would trigger different deformation and failure scenarios compared to indentation of a single cell supported by a rigid flat surface. In order to investigate large deformations characteristic of battery module, a custom experimental set up has been built where the pouch cell was deformed against a compliant backing, which was represented by a ballistic clay. Experiments were also conducted on deformation of stacks of 10 pouch cells, - configuration representing half-module in Ford Focus EV battery pack without cooling plates and structural components. Comparison of the results shows promise for the compliant backing setup for safety evaluation of battery cells under more realistic conditions compared to indentation of single cell against undeformable backing where compression and electrode particle penetration through separator could be the major mechanism for short circuit.

25 ENERGY STORAGE↗
DOE OSTI2022

Modeling the Effects of Drift Orbit Bifurcation on Radiation Belt Electrons

Abstract Drift orbit bifurcation (DOB) has been suggested to play a major role in the loss and transport of radiation belt electrons since it violates the second adiabatic invariants of particles and makes the third invariant undefined. Results from our guiding‐center test particle simulations using the Tsyganenko‐1989c magnetic field model show that the DOB could affect a broad region of the outer radiation belt, which can penetrate inside the geosynchronous orbit at Kp ≥ 3, and its effects are more significant further away from the Earth, at a higher Kp and for higher electron energies. Specifically, the short‐term simulation results after one electron drift show both traditional and nontraditional DOB transport of electrons, with the nontraditional DOB, caused by a third minimum of the magnetic field strength near the equator, reported here for the first time. Moreover, our results show large ballistic jumps in the second invariant and radial distance for electrons at high equatorial pitch angles after one drift. In addition, long‐term DOB transport coefficients of electrons over many drifts are calculated based on our simulation results. We find that the pitch angle and radial diffusion coefficients of electrons due to DOB could be comparable to or even larger than those caused by electron interactions with chorus and Ultra‐Low‐Frequency waves, respectively. In sum, our results demonstrate that DOB could cause effective loss and transport of radiation belt electrons even in the absence of waves.

Astronomy & Astrophysics↗
DOE OSTI2022

Thermite and intermetallic projectiles examined experimentally in air and inert gas environments

Intermetallic (aluminum and zirconium) and thermite (aluminum and molybdenum trioxide) projectiles were launched using a high velocity impact ignition testing system. The experiments were designed to simulate reactivity in high (argon) and low (air) altitude environments. The projectiles were launched into a chamber that included a steel target plate for projectile penetration before impacting a rear witness plate. The chamber was semi-sealed and instrumented for quasi-static pressure data. The results provide an understanding of energy release from the projectile materials and of the environmental influence on performance. The transient pressure traces provide insight into reaction kinetics. A bifurcation in transient pressure rise was an indication of a shift in reaction kinetics from the inherent reactive material to metal oxidation with the environment. The bifurcation was delayed by about 0.15 ms for the intermetallic relative to the thermite, evidence that the thermite reaction proceeded faster upon impact than the intermetallic. The two-step process (impact ignition of the reactive material followed by metal oxidation) was shown to produce higher energy conversion efficiencies than projectiles composed of pure fuel (i.e., aluminum) reported previously. Both reactive materials showed energy conversion efficiencies greater than 30% (for air) and 50% (for argon), and an explanation of underestimated efficiency and energy losses is provided. These results have implications for advancing formulations for ballistic applications. Structural reactive materials can be used to modify the effective reactivity of metal-containing formulations in varied atmospheric environments.

36 MATERIALS SCIENCE↗