Shock responses of nanoporous gold subjected to dynamic loadings: Energy absorption

Abstract

Using the finite element analysis, we investigate the shock response, deformation behavior and energy–absorbing characteristics of stochastic bicontinuous nanoporous gold computationally, considering the effects of impact speed and relative density of materials. Three deformation modes during shocking, quasi–static compression, transition state and dynamic compression, are observed with the increasing impact speeds and the corresponding internal deformation mechanisms are demonstrated. The shock response under low–speed loading is similar to the R–LHP–L materials model, and it is more inclined to the R–S–H model as the impact speed rises. The peak stress, plateau stress, densification strain, energy, specific energy absorption (per unit volume) are assessed quantitatively. The peak stress shows a monotonous increase with impact speed, due to the enhanced inertial effect. The plateau stress and energy–absorbing efficiency are insensitive to low impact velocity, but significantly enhanced under high–speed loading. Remarkably, the results show that the energy absorption efficiency of nanoporous gold is better than conventional foam materials and nanofluidic energy absorption and dissipation system. The research not only further clarifies the shock responses and associated mechanisms of NPG, but also promotes its industrial application as an energy–absorbing material.