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It is known [1, 2] that fast heating of materials by pulsed flows of penetrating radiation gives rise to compressive stresses whose amplitude in the solid-phase region is proportional to the concentration of the absorbed energy.The time lag of the absorbing medium causes a motion in the form of compression waves (or shock waves) and expansion waves. The interaction of two counter waves of the latter type gives rise to tensile stresses in the material with duration rt "-" A/c (A is the thickness of the heated layer and c is the speed of sound). The amplitude of these stresses depends, in the general case, on the absorbed energy, the heating rate (the rate of energy supply), the distribution of the absorbed energy in mass, and the physicomechanical properties of the medium. The appearance of tensile stresses produces conditions for the development of failure. When critical amplitude-time characteristics of the impulse of tensile stresses are reached in a cross section of the sample, failure of the normal separation (spalling) type occurs in it.Investigation of the dynamic effects caused by fast heating of a material is very important for applications, because the capabilities of modern high-energy pulsed facilities are largely determined by the mechanical strength of elements, units, and constructions.The thermal-shock method used in studies of failure allows a considerable extension of the range of the material states studied as compared with conventional methods (shock-wave and explosion loadings [3, 4]). Thus, the results of these investigations provide new information on the behavior of specific materials and are of independent importance for the physics of failure, in particular, in developing models of failure under high-speed deformation that fit the process well.Materials Can be fast heated by impulsive penetrating radiation (in particular, by a nuclear explosion [5]) and by pulsed beams of charged particles [3,[6][7][8][9][10]. The spalling of some solid media (colored ice and polyvinyl chloride plastic) under absorption of the laser-radiation energy is considered in [1, 8, 10]. The spalling of some metals upon fast space heating by high-current electron beams is described in [3, 5,[7][8][9] 10].Sources of impulsive radiation allow one to investigate the behavior of materials in the region of extreme loading parameters and over a wide range of initial temperatures.In studies of the failure of metals under laboratory conditions, high-current accelerators of relativistic electrons are the most widely used sources of pulsed pressure. Use of these accelerators offers unique possibilities and new avenues of attack on the problem of failure of solid bodies in the submicrosecond range of durability for the following acting parameters: rate of energy supply dE~dr of up to 10 al J/(g 9 sec), concentration of the absorbed energy E ~ 1-103 J/g, initial temperatures To = 4K-0.8Tmelt, and electron energy Ee "~ 1-10 MeV. The experimental methods developed to date in combination with mathematical modeling make it possib...

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Abstract. In the paper there are considered dynamic properties of dissipative structures that make it possible to get time dependence of cascade accumulation of failure centers at different stages of failure process. There is presented a hierarchy model of dynamic failure based on wide experimental materials, mathematical formalism of percolation theory, fractal geometry.