Configurational effects on shock wave propagation in Ni-Al multilayer composites

Abstract

The shock compression response of cold-rolled Ni and Al multilayered composites at various angles of inclination are investigated by employing meso-scale simulations. The orientation of the laminate layers in the multilayered composite is varied at 0°, 45°, and 90° to the direction of shock front propagation to determine and understand the resulting changes in the shock compression response. Real, heterogeneous microstructures, obtained from optical micrographs of the multilayered composite cross-section, are incorporated into the Eulerian, finite volume code, CTH. The simulations are performed to establish the role that the orientation of material interfaces plays in the dispersion and dissipation of the shock wave as well as the US-UP relationship for each configuration. Noticeable differences are observed at the meso-scale in the pressure, temperature, and strain response, as a function of the underlying microstructure. Geometric dispersion is seen to alter the shape of the resulting pressure pulse and inhibit the development of a steady-state shock wave in the laminate geometry. This effect is heightened by the extensive non-uniformities of the layering caused by cold-rolling. Additionally, two-dimensional effects of strain are seen to increase the dissipation of the shock wave through interfacial heating and shearing, resulting in high levels of viscosity and attenuation. While the effects of dispersion are minimal on the bulk response of the multilayered composite, the high rate of dissipation is seen to change the dependence of the shock velocity on the particle velocity, making dissipation a major contributor to the bulk response of these composites under shock compression.