Dynamic Compression of Porous Tungsten

Boade, R. R.

doi:10.1063/1.1658272

Cited by 44 publications

(15 citation statements)

References 7 publications

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“…In addition to these features, sintered powders, foam-based materials, and ceramics whose particles are connected by a skeleton have additional peculiarities caused by skeleton compression or breakdown. For this reason, the behavior of a porous or fragmented material under shock-wave compression can be characterized by propagation of complicated multi-wave structures consisting of one or several elastic precursors and a wave of irreversible compression [5][6][7][8][9][10]. If the particles of a porous 474 0010-5082/05/4104-0474…”

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confidence: 99%

“…For this reason, the behavior of a porous or fragmented material under shock-wave compression can be characterized by propagation of complicated multi-wave structures consisting of one or several elastic precursors and a wave of irreversible compression [5][6][7][8][9][10]. If the particles of a porous medium are connected by a skeleton, a three-wave configuration propagates over such a medium [5][6][7]9]. The first wave is elastic, the second wave is generated by skeleton breakdown, and the third wave is caused by splitting of fragments and a decrease in the degree of their anisotropy, i.e., is a wave of irreversible compression.…”

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Effect of Strength and Plasticity of the Material and Particle Size of a Porous Medium on Shock-Wave Deformation

Огородников

Zhernokletov

Mikhailov

et al. 2005

Combust Explos Shock Waves

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The process of dynamic deformation of shock-loaded cylindrical "porous" samples of lead, tungsten, and the 95% W + 3.5% Ni + 1.5% Fe alloy consisting of particles 0.1-2.5 mm in size is considered. The shock-wave intensity was slightly lower than the values corresponding to complete compaction of the material. The influence of the particle size and material strength and plasticity on the processes considered is examined.In solving a number of applied problems associated, e.g., with acceleration of cylindrical shells by the energy of an explosion, one has to predict the characteristics of this process. The problem becomes much more complicated if the shell material loses its compactness during acceleration. The reasons for the loss of compactness can be spalling of the shell, its fragmentation by shear stresses, or the loss of stability in the course of shell implosion [1-3]. To correctly calculate the shell motion in such a state, one has to know the behavior of the fragmented material under dynamic compression. A medium with discontinuities is called a damaged, fragmented, or porous medium. Examples of such media are sand, crushed stone, chips, sintered powders, various foam-based materials, and ceramics. Investigation of their behavior under dynamic compression, especially in the range of pressures corresponding to their complete compaction, is of independent interest. It should be noted that development of reliable models of deformation of such materials is hindered by the lack of experimental data on their behavior under dynamic compression. This particularly refers to materials with a wide range of characteristic particle sizes (from tens of micrometers to several millimeters).In the range of comparatively low pressures, particles of materials under consideration under dynamic or shock-wave loading are first loaded by the shock wave (SW) and then are unloaded to surrounding pores. Because of the finite volume of the "porous" space, the particles experience several circulations of compression and rarefaction waves. This leads to formation of a transitional zone between the SW front and the region of final states; the width of this zone is determined by the time of decay of compression and rarefaction waves circulating in the particles or the time of pore implosion and by the thermal relaxation of particles [4]. When the oscillations decay, the SW propagates in a steady mode; dissipation of kinetic energy of the particle material in the shock-transition zone results in an increase in the thermal component of internal energy and in enhanced shock-induced heating of the porous material. In addition to these features, sintered powders, foam-based materials, and ceramics whose particles are connected by a skeleton have additional peculiarities caused by skeleton compression or breakdown. For this reason, the behavior of a porous or fragmented material under shock-wave compression can be characterized by propagation of complicated multi-wave structures consisting of one or several elastic precursors and a wave of ir...

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confidence: 99%

Effect of Strength and Plasticity of the Material and Particle Size of a Porous Medium on Shock-Wave Deformation

Огородников

Zhernokletov

Mikhailov

et al. 2005

Combust Explos Shock Waves

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“…Cavity collapse plays a prominent role in the initiation of energetic reactions in explosives [5]. In this side, most of previous studies concerned the Hugoniots [6][7][8][9][10][11][12][13] and the equation of state [14][15][16]. It is known that, under strong shocks, the porous material is globally in a nonequilibrium state and show complex dissipative structures.…”

Section: Introductionmentioning

confidence: 99%

Morphological characterization of shocked porous material

Xu¹,

Zhang²,

Pan³

et al. 2009

J. Phys. D: Appl. Phys.

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Abstract. Morphological measures are introduced to probe the complex procedure of shock wave reaction on porous material. They characterize the geometry and topology of the pixelized map of a state variable like the temperature. Relevance of them to thermodynamical properties of material is revealed and various experimental conditions are simulated. Numerical results indicate that, the shock wave reaction results in a complicated sequence of compressions and rarefactions in porous material. The increasing rate of the total fractional white area A roughly gives the velocity D of a compressive-wave-series. When a velocity D is mentioned, the corresponding threshold contour-level of the state variable, like the temperature, should also be stated. When the threshold contour-level increases, D becomes smaller. The area A increases parabolically with time t during the initial period. The A(t) curve goes back to be linear in the following three cases: (i) when the porosity δ approaches 1, (ii) when the initial shock becomes stronger, (iii) when the contour-level approaches the minimum value of the state variable. The area with high-temperature may continue to increase even after the early compressive-waves have arrived at the downstream free surface and some rarefactive-waves have come back into the target body. In the case of energetic material needing a higher temperature for initiation, a higher porosity is preferred and the material may be initiated after the precursory compressive-waves have scanned all the target body. One may desire the fabrication of a porous body and choose appropriate shock strength according to what needed is scattered or connected hotspots. With the Minkowski measures, the dependence on experimental conditions is reflected simply by a few coefficients. They may be used as order parameters to classify the maps of physical variables in a similar way like thermodynamic phase transitions.Submitted to: J. Phys. D: Appl. Phys.

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“…Shock compressibility of tungsten is investigated at megabar pressure with use of traditional explosive systems [19,13,65,66] and two-stage light-gas gun [67,68]. Results of shock compression of porous tungsten, obtained with the use of traditional plain and hemispherical explosive drivers to 3 Mbar [66,69,[70][71][72], significantly expand investigated region of the phase diagram to lower densities. Nuclear impedance measurements are reported at 60 Mbar [73].…”

Section: Eos Of Tungstenmentioning

confidence: 99%

Equations of State of Matter at High Energy Densities

Фортов¹,

Ломоносов²

2014

TOPPJ

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Abstract:The physical properties of hot dense matter over a broad domain of the phase diagram are of interest in astrophysics, planetary physics, power engineering, controlled thermonuclear fusion, impulse technologies, enginery, and other applications. The present report reviews the contribution of modern experimental methods and theories to the problem of the equation of state (EOS) at extreme conditions. Experimental techniques for high pressures and high energy density cumulation, the drivers of intense shock waves, and methods for the fast diagnostics of high-energy matter are considered. It is pointed out that the available high pressure and temperature information covers a broad range of the phase diagram, but only irregularly and, as a rule, is not thermodynamically complete; its generalization can be done only in the form of a thermodynamically complete EOS. As a practical example, construction of multi-phase EOS for tungsten is presented. The model's results are shown for numerous shock-wave data, the high-pressure melting and evaporation regions and the critical point of tungsten.

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Dynamic Compression of Porous Tungsten

Cited by 44 publications

References 7 publications

Effect of Strength and Plasticity of the Material and Particle Size of a Porous Medium on Shock-Wave Deformation

Effect of Strength and Plasticity of the Material and Particle Size of a Porous Medium on Shock-Wave Deformation

Morphological characterization of shocked porous material

Equations of State of Matter at High Energy Densities

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