Ivanov S. Determination of main physical criteria of material resistance to fracture under high-velocity impact

Physical dependencies and mechanisms of material reaction (dynamic response) to high-velocity impact loading are established, material science criteria are determined as well as ways of enhancing impact resistance under conditions of stationary fracturing for brittle ceramic materials. With the help of developed model of expansion of spherical cavity in brittle material with application of the concept of ultimate velocity of fracture fronts the resistance to fracturing of brittle material under local loading (penetration) for high impact velocities was determined. Energy structure of material resistance (energy losses on deformation, fracturing, and compaction of comminuted material) was established. Resistance of brittle material with initial porosity to local loading (penetration) was determined with the help of developed model of spherical cavity expansion using rheology of porous materials. Energy structure of penetration resistance of such material was analyzed. For a class of porous plastic materials the resistance to local loading (penetration) was determined as well as energy losses on deformation, plastic flow and densification with the help of developed model, which takes into account rheology of porous materials. With the help of refined model of Alekseevskii-Tate of penetration of eroding projectiles into brittle materials and developed model of penetration of rigid projectiles into plastic and quasi-plastic materials based on the motion equations for incompressible fluid main parameters of penetration were investigated, relation between penetration parameters and physical properties of materials was analyzed. On this basis methods of prediction of service characteristics were developed as well as methods and criteria of improvement of working parameters. Developed models have potential for modification and refinement for adaptation to investigated materials.