Dynamic spherical cavity expansion in brittle ceramics

Abstract In this paper we derived the pressure required to open a spherical cavity in an infinite brittle ceramic at a constant speed. The ceramic material is assumed to crack upon reaching its elastic limit. Subsequent failure of the cracked material due to compressive failure renders pulverization of the material. The pulverized material is assumed to follow a Mohr–Coulomb type constitutive behavior. The results show that at high cavity expansion speeds the comminuted region outruns the cracked region, i.e. the cracked region disappears. At very high cavity expansion speeds the comminuted zone propagation speed saturates at a level slightly below the longitudinal wave speed. Limited comparison with experimental penetration resistance shows reasonable agreement between theory and experiment.

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