Mitigating Spall Fracture of Ductile Materials by Introducing Porosity

A material when subjected to shock/impact loading conditions can undergo spall fracture, when the compressive waves reflect off interfaces and free surfaces as tensile waves. Experiments have shown that in ductile materials, spall fracture is induced by the growth of pre-existing pores and/or nucleation and growth of new pores. However, porosity in ductile materials also introduces plastic compressibility that may lead to energy absorption and thus mitigate spall fracture. Following this, we investigate the role of initial porosity and nucleation of new pores on the spall fracture of porous ductile materials subjected to flyer plate impact loading conditions using finite element analysis. Our results show that porosity in ductile materials under certain circumstances can indeed mitigate spall fracture by attenuating stress waves. In this presentation we will focus on the results correlating impact velocity, initial porosity, and nucleation of new pores on the propensity of spall fracture of ductile materials.