Large deformation dynamic plasticity at an elastic-plastic interface

Abstract

T he diffraction grating measurements of finite strain nonlinear wave fronts are described for elastic-plastic interface experiments. Close agreement with theoretical prediction on both sides of the interface is shown to exist when the non-viscous finite deformation parabolic stress-strain runction for annealed polycrystalline aluminium is introduced into the finite amplitude wave theory of Taylor, von Karman and Rakhmatulin, and into the nonlinear unloading wave theory of Lee. Dynamic studies of interface lubrication, of Pochhammer-Chree oscillations in the hard bar, and of variations in the mode of unloading are included providing detailed experimental correlation with theory under these varied conditions. Diffraction grating surface-angle measurements in the elastic-plastic interface experiment are shown to provide a detailed demonstration that the nonlinear finite amplitude wave fronts are one-dimensional extending across the entire specimen diameter. These measurements also have demonstrated experimentally that finite amplitude wave propagation in dynamic plasticity is an incompressible distortional deformation.