Damage accumulation mechanisms during dynamic compressive failure of boron carbide

Abstract

This paper explores the compressive response of two grades of boron carbide across a range of strain rates between 102 to 103 s−1. Using ultra-high-speed photography to perform digital image correlation in conjunction with strain gauges, the evolution of apparent elastic moduli was tracked through the failure process. Analysis of damage metrics shows that the two most important measures of damage accumulation in these materials are apparent changes to shear modulus and Poisson’s ratio, rather than only apparent changes to Young’s modulus as is commonly assumed in the literature. For one grade of the boron carbide the range of strain-rates studied also included a transition from quasi-static-type failure behavior where bulking was not a significant factor, to dynamic-type failure where bulking became a significant influence on failure; this transition was linked to material-specific fracture mechanisms. For the other grade of boron carbide, only dynamic-type failure was seen in this strain-rate range, suggesting that the transition point was at a lower strain-rate.