The response of porous materials to shockwaves is an ongoing focal point for various industrial and military applications, including dynamic compaction of powders, the design of blast mitigation devices, and collision processes in the solar system. Additionally, with the advancement of additive manufacturing, incorporating voids in material design offers a potential avenue to create lightweight materials with high energy dissipation properties. This is crucial for preventing in-structure electronic components or human bodies from strong acceleration forces.
In this study, we employ finite element calculations to analyze steady shockwaves formed in porous metals during planar impact experiments. Initially, we examine a population of spherical voids with the same initial radius, quasi isotropically distributed within a viscoplastic metallic matrix. The pore size significantly influences the shock layer structure, corroborating results obtained from analytical approaches found in the literature (e.g., Czarnota et al., 2017, 2020). This influence is attributed to micro-inertia effects induced by radial accelerations near collapsing pores, which scale with the square of the initial void size.
Subsequently, we extend the finite element approach to characterize the influence of void shape and spatial arrangement. Our analysis offers new insights into the role of porous microstructure (size, shape, spatial distribution of voids, together with the initial porosity) on both Hugoniot data and shock structure. The case of porous aluminum is particularly explored with references to experimental data.