Wave propagation and permanent densification in a porous steel submitted to laser-driven shocks

Abstract
Instrumented laser shock experiments have been performed to investigate the response of a sintered porous steel to uniaxial compressive loading at very high strain rates. The water-confinement technique has been used to increase both amplitude and duration of the laser shocks. Two steels of different initial porosities have been studied. Wave profiles have been measured with thick piezoelectric transducers stuck at the back of the steel targets. Residual compaction has been estimated by post-shock microscopic examination of the recovered samples. A simple constitutive material model, based on a macroscopic description involving the equation of state of the compact steel and a traditional P-α compaction model, has been adapted and introduced in a one-dimensional hydrocode to simulate the tests. A correct overall agreement has been obtained between measured and computed wave profiles, and the residual porosity distribution predicted by the model has been compared to that observed along the direction of wave propagation.