Perturbation evolution at a metal-metal interface subjected to an oblique shock wave: Supersonic velocity of the point of contact

The perturbation evolution at the interface between identical metals (metal plates) that is exposed to high-speed oblique shock waves is observed experimentally for the first time (the waves are attached to the point of contact, so that a cumulative jet cannot form). The experiments are numerically simulated by the two-dimensional Lagrange method. An elastoplastic model where the dynamic yield strength is a function of material state parameters is employed. An analytical technique to treat instability development under given loading conditions is suggested. High strains produce a high-temperature zone near the interface (thermal softening zone). A short-lived shear flow with a high velocity gradient depending on the angle and velocity of plate collision is observed. In this zone, the shear modulus and the yield strength are appreciably lower than under normal conditions, which favors instability development.