Photon Doppler Velocimetry (PDV) Characterization of Shaped Charge Jet Formation

Zellner, Michael B.; Vunni, George B.

doi:10.1016/j.proeng.2013.05.012

Cited by 11 publications

(7 citation statements)

References 8 publications

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“…Detonation of the shaped charge in vacuum forms a jet with a 9.25 mm/μs non-stretching tip particle (l ~ 18 mm, d ~ 6 mm) which is followed by a stretching cylindrical jet (approximately 3 -4 mm in diameter). A detailed analysis of the jet and its formation in air was performed by Zellner and Vunni [14] and some characteristics of the jet were measured by Summers [15]. For the current study, it was desired to have a jet without a large tip particle and of a maximum velocity appreciably lower than the wave speed of the target material.…”

Section: Experimental Methodsmentioning

confidence: 99%

Shaped Charge Jet Penetration of Alon® Ceramic Assessed by Proton Radiography and Computational Simulations

Zellner

Becker

Dandekar

et al. 2015

Procedia Engineering

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This work describes the use of proton radiography and continuum simulations to investigate the mechanics of a copper jet penetrating unconfined ALON ® transparent ceramic. Use of proton radiography enabled characterization of the jet and ceramic material at 21 time steps, in situ, throughout the penetration process. These radiographs provide time-evolution data pertaining to the material densities, cavity growth, and material failure. The data were compared to legacy analytical penetration models and to a simulation of the event computed using a continuum multi-physics code. These comparisons revealed additional insights into the penetration mechanics as well as strengths and weaknesses of the computational algorithms and material models used in the simulations.

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Section: Experimental Methodsmentioning

confidence: 99%

Shaped Charge Jet Penetration of Alon® Ceramic Assessed by Proton Radiography and Computational Simulations

Zellner

Becker

Dandekar

et al. 2015

Procedia Engineering

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“…To avoid the second injury, the samples were obtained by soft recovery. The free surface velocity curve of the sample was measured by photonic doppler velocimetry (PDV) system, and the laser probe placed on the free surface of the sample to measure the particle velocity in real time [27].…”

Section: Single-stage Light Gas Gun Experimentsmentioning

confidence: 99%

Effects of the phase interface on initial spallation damage nucleation and evolution in dual phase titanium alloy

Yang

Jiang

Wang

et al. 2018

Materials Science and Engineering: A

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A B S T R A C TThe Ti-6Al-4V dual phase alloy samples were dynamic loaded by one-stage light gas gun experiment and samples with initial spallation were softly recovered. During the loading experiment, the velocity of free surface particles was measured by photonic doppler velocimetry (PDV). The effect of α/β phase interface on nucleation, growth, and coalescence of dynamic damage in Ti-6Al-4V were investigated by 2-D or 3-D testing techniques, such as optical microscopy(OM), x-ray computer tomography(XRCT), and electron backscattered diffraction(EBSD). The results showed that the majority of voids were nucleated within α phases, rather than on the α/β phase interface as predicted by quasi-static damage theory. Due to the effects of reflection and transmission of shock wave at the phase interface, a tensile pulse would be formed within α phase when the shock wave transmit from α phase with high impedance to β phase with low impedance. When this tensile pulse was large enough, voids would be formed within α phase. The analyses of OM and XRCT indicated that the voids at the beginning of nucleation were nearly spherical, then grew up along the direction of 45°with the shock loading direction, and finally the rod-shaped voids were formed. Besides, the voids were not randomly nucleated within α phase, and the EBSD analysis showed that the voids were mainly nucleated at grain boundary triple points which composed of grains with large difference of Taylor Factor(TF) value within α phase. This is because the difference of plastic deformation capacity of this grains is larger, and it is easier to produce stress concentration. Thus these sites became the prior nucleation position of voids.

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“…Regarding numerical modeling, two aspects are crucial to reproduce the jet generation process and its fragmentation. As the phenomenon is mainly in the field of large deformations, historical simulations have favored Eulerian approaches [1][2][3][4]. However, facing a huge compromise between accuracy and computation times particularly regarding the jet fragmentation process, Lagrangian and ALE approaches were then evaluated [3,5,6].…”

Section: Introductionmentioning

confidence: 99%

“…As the phenomenon is mainly in the field of large deformations, historical simulations have favored Eulerian approaches [1][2][3][4]. However, facing a huge compromise between accuracy and computation times particularly regarding the jet fragmentation process, Lagrangian and ALE approaches were then evaluated [3,5,6]. Among them is the Smoothed Particle Hydrodynamics method and we focus here on a recent method called γ-SPH-ALE [7].…”

Section: Introductionmentioning

confidence: 99%

Innovative meshless approach for shaped charges applications

Collé¹,

Limido²,

Unfer³

et al. 2022

J. Phys.: Conf. Ser.

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We focus here on modelling shaped charges. Combining large deformations, numerous interfaceproductions, and strong damage mechanisms, those events are particularly challenging from a numerical point of view. Eulerian finite element methods are classically used for such modeling.However, they induce very long computation times, accuracy losses (projection algorithms), anddifficulties with opening criteria related to jet fragmentation. Among the Lagrangian approaches, the meshless method called Smoothed Particle Hydrodynamics (SPH) appears as a relevant alternative to prevent such shortcomings. Based on a set of moving interpolation points, it disregards any connectivity between its elements which makes it naturally well suited to handle material failure. Nevertheless, SPH schemes suffer from well-known instabilities questioning their accuracy and activating nonphysical processes,such as numerical fragmentation. Many stabilizing tools are available in the literature however, they either raise conservation and consistency issues or drastically increase the computation times. We propose then to use an alternative scheme called γ-SPH-ALE. Based on the ALE framework, it achieves robust and consistent stabilization through an arbitrary description of motion. Thanks to CFL-like conditions obtained through a nonlinear stability analysis, the scheme stability is ensured. By preventing spurious oscillations in elastic waves and correcting the so-called tensile instability, both stability and accuracy are increased regarding classical approaches. Also, taking advantage of GPU computing, such results are achieved in reduced computation times contrary to classical CPUimplementations. Its implementation on a “Viper” shaped charge shows that the scheme handles the jet generation process as well as its resulting interaction with a target.

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Photon Doppler Velocimetry (PDV) Characterization of Shaped Charge Jet Formation

Cited by 11 publications

References 8 publications

Shaped Charge Jet Penetration of Alon® Ceramic Assessed by Proton Radiography and Computational Simulations

Shaped Charge Jet Penetration of Alon® Ceramic Assessed by Proton Radiography and Computational Simulations

Effects of the phase interface on initial spallation damage nucleation and evolution in dual phase titanium alloy

Innovative meshless approach for shaped charges applications

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