Hypervelocity shrapnel damage assessment in the nif target chamber

Tokheim, R. E.; Curran, D. R.; Seaman, L.; Cooper, Thomas; Anderson, Andrew T.; Burnham, A.K.; Scott, J. M.; Latkowski, J. F.; Schirmann, D.

doi:10.1016/s0734-743x(99)00136-0

Cited by 17 publications

(9 citation statements)

References 2 publications

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“…20,21 The generation of high velocity metallic solid or liquid fragments in these experiments can damage vacuum chambers or measurement devices. To assess and reduce such risks of damage, the fragments size and ejection velocity must be efficiently predicted by models based on experimental data.…”

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confidence: 99%

Skew photonic Doppler velocimetry to investigate the expansion of a cloud of droplets created by micro-spalling of laser shock-melted metal foils

Loison

Rességuier

Dragon

et al. 2012

Journal of Applied Physics

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International audienceDynamic fragmentation in the liquid state after shock-induced melting, usually referred to as micro-spallation, is an issue of great interest for both basic and applied sciences. Recent efforts have been devoted to the characterization of the resulting ejecta, which consist in a cloud of fine molten droplets. Major difficulties arise from the loss of free surface reflectivity at shock breakout and from the wide distribution of particle velocities within this cloud. We present laser shock experiments on tin and aluminium, to pressures ranging from about 70 to 160GPa, with complementary diagnostics including a photonic Doppler velocimeter set at a small tilt angle from the normal to the free surface, which enables probing the whole cloud of ejecta. The records are roughly consistent with a one-dimensional theoretical description accounting for laser shock loading, wave propagation, phase transformations, and fragmentation. The main discrepancies between measured and calculated velocity profiles are discussed in terms of edge effects evidenced by transverse shadowgraphy

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mentioning

confidence: 99%

Skew photonic Doppler velocimetry to investigate the expansion of a cloud of droplets created by micro-spalling of laser shock-melted metal foils

Loison

Rességuier

Dragon

et al. 2012

Journal of Applied Physics

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“…7 In recent decades, extensive investigations on particle ejection have been performed because of its important role in many scientific and engineering fields, including explosion damage, 8 pyrotechnics, 9 and inertial confinement fusion. 10,11 Many experimental approaches have attempted to measure the ejection production, such as the Asay foil, 3,12 foam recovery, 13 piezoelectric probes, 4,14 Fraunhofer holography, 15,16 X-ray/proton radiography, 2,17 Mie scattering, 17,18 , and photon Doppler velocimetry (PDV). [19][20][21][22][23][24][25] The main quantities of interest are the particles' velocity, diameter, and total area mass.…”

Section: Introductionmentioning

confidence: 99%

Reconstruction and interpretation of photon Doppler velocimetry spectrum for ejecta particles from shock-loaded sample in vacuum

Shi,

Ma,

Dang

et al. 2020

Preprint

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The photon Doppler velocimetry (PDV) spectrum is investigated in an attempt to reveal the particle parameters of ejecta from shock-loaded samples in a vacuum. A GPU-accelerated Monte-Carlo algorithm, which considers the multiplescattering effects of light, is applied to reconstruct the light field of the ejecta and simulate the corresponding PDV spectrum. The influence of the velocity profile, total area mass, and particle size of the ejecta on the simulated spectra is discussed qualitatively. To facilitate a quantitative discussion, a novel theoretical optical model is proposed in which the single-scattering assumption is applied. With this model, the relationships between the particle parameters of ejecta and the peak information of the PDV spectrum are derived, enabling direct extraction of the particle parameters from the PDV spectrum. The values of the ejecta parameters estimated from the experimental spectrum are in good agreement with those measured by a piezoelectric probe.

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“…5,6 During shock compression, local temperature and pressure rapidly increase at or near the shock front, which can result in inelastic deformation, possibly coupled with chemical reactions, [7][8][9][10][11][12][13] if they exceed the mechanical or chemical stability limits, respectively. Recent computational and experimental studies of crystalline solids (metals, ceramics, and energetic materials) subjected to shock compression show that inelastic deformation is manifested in various ways: dislocation, [14][15][16][17][18][19][20][21][22][23] twinning, [24][25][26][27][28][29] shear banding, 23,30,31 melting, [32][33][34] and polymorphic phase transition, 31,[35][36][37][38][39][40][41] depending on the shock strength, crystallographic orientation, and crystal structure.…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulations of shock waves in oriented nitromethane single crystals: Plane-specific effects

Sewell

Thompson

2012

The Journal of Chemical Physics

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Molecular dynamics simulations of supported shock waves (shock pressure P(s) ∼ 15 GPa) propagating along the [110], [011], [101], and [111] directions in crystalline nitromethane initially at T = 200 K were performed using the nonreactive Sorescu-Rice-Thompson force field [D. C. Sorescu, B. M. Rice, and D. L. Thompson, J. Phys. Chem. B 104, 8406 (2000)]. These simulations, combined with those from a preceding study of shocks propagating along [100], [010], and [001] directions in nitromethane for similar conditions of temperature and shock pressure [L. He, T. D. Sewell, and D. L. Thompson, J. Chem. Phys. 134, 124506 (2011)], have been used to study the post-shock relaxation phenomena. Shocks along [010] and [101] lead to a crystal-crystal structure transformation. Shocks propagating along [011], [110], [111], [100], and [001] exhibit plane-specific disordering, which was characterized by calculating as functions of time the 1D mean square displacement (MSD), 2D radial distribution function (RDF), and 2D orientation order parameter P(2)(θ) in orthogonal planes mutually perpendicular to the shock plane; and by calculating as functions of distance behind the shock front the Cartesian components of intermolecular, intramolecular, and total kinetic energies. The 2D RDF results show that the structural disordering for shocks along [100], [110], and [111] is strongly plane-specific; whereas for shocks along [001] and [011], the loss of crystal structural order is almost equivalent in the orthogonal planes perpendicular to the shock plane. Based on the entire set of simulations, there is a trend for the most extensive disordering to occur in the (010) and (110) planes, less extensive disordering to occur in the (100) plane, and essentially no disordering to occur in the (001) plane. The 2D P(2)(θ) and 1D MSD profiles show, respectively, that the orientational and translational disordering is plane-specific, which results in the plane-specific structural disordering observed in the 2D RDF. By contrast, the kinetic energy partitioning and redistribution do not exhibit plane specificity, as shown by the similarity of spatial profiles of the Cartesian components of the intermolecular, intramolecular, and total kinetic energies in orthogonal planes perpendicular to the shock plane.

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Hypervelocity shrapnel damage assessment in the nif target chamber

Cited by 17 publications

References 2 publications

Skew photonic Doppler velocimetry to investigate the expansion of a cloud of droplets created by micro-spalling of laser shock-melted metal foils

Skew photonic Doppler velocimetry to investigate the expansion of a cloud of droplets created by micro-spalling of laser shock-melted metal foils

Reconstruction and interpretation of photon Doppler velocimetry spectrum for ejecta particles from shock-loaded sample in vacuum

Molecular dynamics simulations of shock waves in oriented nitromethane single crystals: Plane-specific effects

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