Ejecta production from shocked Pb surface via molecular dynamics

Ren, Guowu; Chen, Yongtao; Tang, Tiegang

doi:10.1063/1.4896902

Cited by 34 publications

(7 citation statements)

References 28 publications

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“…To our knowledge, only recent MD simulations performed on atomistic systems allowed to provide directly from computations ejecta size distributions [25][26][27]. Particulate computations are indeed at the good scale to provide information on the microscopic mechanisms of plastic deformation and/or fragmentation of metals under melting or release melting conditions [25][26][27][28][29][30][31]. However, the main objection on these simulations is that the scales and times involved are smaller than those in real structures by at least 3 or 4 orders of magnitude; and in the absence of reliable data, it is effectively not yet possible to confirm the results with experiments or models.…”

Section: Introductionmentioning

confidence: 99%

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Durand

Soulard

2015

Journal of Applied Physics

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Abstract:The mass (volume and areal densities) versus velocity as well as the size versus velocity distributions of a shock-induced cloud of particles are investigated using large scale molecular dynamics (MD) simulations. A generic three-dimensional tin crystal with a sinusoidal free surface roughness (single wavelength) is set in contact with vacuum and shock-loaded so that it melts directly on shock. At the reflection of the shock wave onto the perturbations of the free surface, two-dimensional sheets/jets of liquid metal are ejected. The simulations show that the distributions may be described by an analytical model based on the propagation of a fragmentation zone, from the tip of the sheets to the free surface, within which the kinetic energy of the atoms decreases as this zone comes closer to the free surface on late times. As this kinetic energy drives (i) the (self-similar) expansion of the zone once it has broken away from the sheet and (ii) the average size of the particles which result from fragmentation in the zone, the ejected mass and the average size of the particles progressively increase in the cloud as fragmentation occurs closer to the free surface.Though relative to nanometric scales, our model may help in the analysis of experimental profiles.2

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Section: Introductionmentioning

confidence: 99%

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Durand

Soulard

2015

Journal of Applied Physics

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“…The jetting factor R is introduced to describe the differences in ejected mass. The jetting factor R of microjet is defined as the ratio of ejected mass to micro defect mass [53,54], which is proposed by Asay [16]. In the simulation results, we define the mass from the spike to the bubble as M J , and the mass from the spike to the theoretical free surface as M F .…”

Section: Influence Of Shock Pulse Duration On Microjetmentioning

confidence: 99%

Microjet formation from the grooved surface of aluminum under shock waves with different pulse durations

Mingyang

Song

Shao

et al. 2020

Modelling Simul. Mater. Sci. Eng.

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The shock-induced microjet phenomenon has attracted much attention due to its importance in shock compression science and technology. The existing researches have shown that shockwave profile has a significant effect on the microjet formation. This work investigates the influence of shock pulse duration on the microjet systematically based on smoothed particle hydrodynamics simulations and theoretical analysis. In fact, when the pulse duration of shock wave is more than 7.31 times the time of shock front passing through groove, the microjet mass and its time-space evolution will be consistent with the case under supported shock. It is shown that there is a critical value for the shock pulse duration (about 4.21 times the time of shock front passing through groove), below which the effect of shock pulse duration is distinct. With decreasing the shock pulse duration, the mass from spike to bubble experiences a rapid increase due to the increase of the velocity gradient behind the free surface, while the mass from spike to the theoretical free surface experiences a gradual reduction because the shock energy reduces. As a result, the spike becomes very thinner and the bubble amplitude is lengthened. The damage will be localized around the groove region. Besides, with the interaction between the release stage of incident waves and the release waves from the groove, the cavities and different low-density fragments are observed.

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“…This simulated model is the same as in Ref. [20] where ejecta production under an unsupported shockwave has been examined. The X, Y , and Z axes are chosen along the [100], [010], and [001] directions, respectively.…”

Section: Simulation Detailsmentioning

confidence: 99%

“…However, careful examination finds that the mass determination in Ref. [20] is for the jet but not for the ejected fragments. Thus, both the experimental measurements and numerically atomistic simulations cannot offer an explicit insight on the influence of shockwave shape on the ejection process, in particular regarding the quantity of the ejecta production.…”

Section: Introductionmentioning

confidence: 99%

“…Several possible reasons are proposed to explain this difference, such as the time-dependent influence of the shock profile on the instability formation and micro-spall separation of layers induced by the stress state upon release at the free surface. As a helpful complement for modeling the ejecta production related to melting and damage, [14][15][16][17][18][19][20][21][22] molecular dynamics (MD) simulations have been carried out to comparatively obtain the quantity of ejecta in Al for supported and unsupported shocks. [19] The simulations exhibit a continuous increase of microjet mass with the increasing shock pressures under supported shocks and this quantity after release melting is larger than that under unsupported shocks.…”

Section: Introductionmentioning

confidence: 99%

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Influence of shockwave profile on ejecta from shocked Pb surface: Atomistic calculations

et al. 2016

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We conduct molecular dynamics simulations of the ejection process from a grooved Pb surface subjected to supported and unsupported shock waves with various shock-breakout pressures (P SB ) inducing a solid-liquid phase transition upon shock or release. It is found that the total ejecta mass changing with P SB under a supported shock reveals a similar trend with that under an unsupported shock and the former is always less than the latter at the same P SB . The origin of such a discrepancy could be unraveled that for an unsupported shock, a larger velocity difference between the jet tip and its bottom at an early stage of jet formation results in more serious damage, and therefore a greater amount of ejected particles are produced. The cumulative areal density distributions also display the discrepancy. In addition, we discuss the difference of these simulated results compared to the experimental findings.

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Ejecta production from shocked Pb surface via molecular dynamics

Cited by 34 publications

References 28 publications

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Mass-velocity and size-velocity distributions of ejecta cloud from shock-loaded tin surface using atomistic simulations

Microjet formation from the grooved surface of aluminum under shock waves with different pulse durations

Influence of shockwave profile on ejecta from shocked Pb surface: Atomistic calculations

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