Mesoscopic picture of fracture in porous brittle material under shock wave compression

Void is one of the most common type of structure flaws existing in brittle materials, which dramatically affects the shock loading response of brittle materials. A quantitative discrete element method is employed in this work to study the fracture characteristics of porous isotropic brittle material under shock wave compression. Scenarios of isolated void, three types of simple distribution and random distribution of voids are computed, from which we find that shear fracture and local tensile fracture are two type of basic fracture modes for brittle material under shock wave compression. Coalescence of damage bands between voids can induce the collapse of voids at relatively low pressure, while stress relaxation caused by damage can shield fracture evolution in a certain zone. The combination of amplification and shielding effects of damage results in a unique pattern of alternate distribution of severe and mild damage zones. These simulation results present a basic physics picture for the understanding of evolution process and mechanism of fracture in porous brittle material under shock wave compression.