A Dynamic Spherical Cavity Expansion Model for Ceramics Considering Shear-Dilatancy

The cavity expansion theory is often used to predict the penetration resistance of a target against a projectile. A dynamic spherical cavity expansion model for ceramic materials is suggested by considering shear-dilatancy effect through introducing a dilatancy-kinematic relation in comminuted region. The comminuted region is further divided into a linear comminuted region (satisfying the Mohr-Coulomb failure criterion) and a saturated comminuted region (satisfying the maximum shear strength), depending on whether the shear strength reaches its maximum (plateau). Firstly, equations for calculating radial stress at cavity surface are derived. Secondly, numerical simulations of cavity expansion process in ceramics at different expansion velocities are conducted. Finally, the effects of key parameters such as compressive strength and density on the cavity surface radial stress are discussed. It is shown that the model predictions for cavity radial stress and interface velocities of cracked and comminuted regions are in good agreement with numerical simulations. It is also shown that compressive strength plays a dominant role in enhancing cavity radial stress and the influence of density increases with increasing cavity expansion velocity.