UC San Diego

Numerical simulations of strong shock wave compression of Al-W laminate materials with different cell size ranging from 1 mm to 4 mm were conducted. Finite element simulations using LS-DYNA were employed with two different durations of loading pulse tailored by changing the length of the impactor. The results of the numerical simulations for homogeneous materials were used for validation of our code by comparing the results of the pressure, the temperature and the final volume with the available Hugoniot data. The focus of this work was on the study of the mechanical parameters and thermodynamic states reached through multiple shock reverberations. The mechanism of the formation of the steady leading front and final states were analyzed under different conditions of loading and laminate mesostructure. It was shown that a steady shock front can be reached even when the final steady state is not established. The results of the numerical simulations of the pressure, the specific volume and the temperature were compared to the values predicted by two models to assess whether these models correctly predict the final state. This work also includes a brief exploration of the effects of mesh refinement and shock viscosity on the simulated final state of the material. It is concluded that an increasing number of interfaces (through the reduction of the layer thicknesses) helps to achieve a steady shape of the leading front and the equilibrium state behind the shock faster. The investigated models correctly predict the final state (within the explored ranges of pressure) in the pressure-specific volume plane. It was also found that the final thermodynamic state is more sensitive to the composition of the layered materials and that the predictions of the models differ from our calculations even when a steady state behind the shock was reached