Numerical Investigations of Perturbation Growth in Aluminum Flyer Driven by Explosion

In this paper we developed an experimental technique and numerical simulation method that we then adopted to investigate the Rayleigh-Taylor instability in metallic materials driven by explosion.We studied experimentally and numerically the growth of the Rayleigh-Taylor instability in an explosion-driven aluminum flyer and showed that the perturbation amplitude growth follows an exponential law over time.The numerical results agree with the experiment qualitatively, but not quantitatively.This is because the aluminum strengthens under high pressure and at high strain rate, and the Steinberg-Guinan constitutive model used in the simulations underestimates the strength of the aluminum as being not great enough to suppress the perturbation growth.By investigating numerically the effects of the initial shear modulus and the initial yield strength on the development of the Rayleigh-Taylor instability of the metallic material, we also found that the initial shear modulus in a specified range does not affect the dynamic yield strength and the increase in the initial yield strength can improve the dynamic yield strength significantly to stabilize the perturbation growth.In other words, the material strength dominates the interface perturbation growth.