Calculation of penetration resistance of brittle materials using spherical cavity expansion analysis

In this paper, we show that the ‘target resistance’ of brittle materials can be calculated accurately using spherical cavity expansion analysis and a conventional brittle material model. The stress field ahead of the tip of the penetrator is assumed to have spherical symmetry. The brittle material is modeled as an elastic material which cracks under tension. The cracked material is considered to be pulverized when it fails in compression, which is then characterized as a Mohr-Coulomb material with pressure dependent shear strength. The target resistance value found from this analysis compares well with the reported experimental values for AD995 alumina (Al₂O₃) and aluminum nitride (A1N).