Strain Rate Effect on the Mechanical Properties of Single Coral Particles under Impact Loads

Abstract

Single particle crushing tests have been performed on coral particles with a size range of 5.5-7 mm. A modified split Hopkinson pressure bar (SHPB) apparatus was utilized to achieve impact loads at high strain rates from 103.0 s-1 to 103.5 s-1. Based on the high-speed images, it is found that particle crushing is mainly induced by tensile fracture. The crack initiations of coral particles tend to follow the weak parts at surface defects. Dynamic fragmentation is the ultimate failure feature. The particle crushing strengths were analyzed in terms of survival probability curves, which are proved to follow the Weibull statistics law. The characteristic strength increases with increasing strain rate, which appears to be linear with a slope of 0.385 in the double logarithm coordinate.