CALCULATION OF PENETRATION RESISTANCE OF BRITTLE MATERIALS USING SPHERICAL CAVITY EXPANSION ANALYSIS

In this paper, we show that the 'target resistance' of brittle materia ls can be calculated accurately using spherical cavity expansion analy sis and a conventional brittle material model. The stress field ahead of the tip of the penetrator is assumed to have spherical symmetry. Th e brittle material is modeled as an elastic material which cracks unde r tension. The cracked material is considered to be pulverized when it fails in compression, which is then characterized as a Mohr-Coulomb m aterial with pressure dependent shear strength. The target resistance value found from this analysis compares well with the reported experim ental values for AD995 alumina (Al2O3) and aluminum nitride (AIN).