High Speed Impact - Test and Simulation

Deformation processes of structures under dynamic loading have been investigated both experimentally and by simulation for many years now. Various rate dependencies in many materials, wave and shock wave phenomena as well as material tests for their quantitative description have been identified. In parallel, mathematical formulations for the observed material behavior and numerical schemes for time dependent approximations of the governing partial differential equations have been developed. Since both the experimental characterization and the numerical simulation demand for assumptions, e.g. the state and distribution of stress and strain in a specimen or in a discretizing unit, increasing complexity of materials demands for advanced test set-ups and numerical methodologies. In this paper, a brief discrimination between the regimes of quasi-static, low-dynamic and high-dynamic loading conditions is given. Related experimental means for material characterization as well as components in the numerical model needed to represent the relevant physical aspects are given by some example cases. Specific emphasis is placed on the characterization of low-impedance materials and on the implementation of a micro-continuum based fabric model into LS-DYNA. An application of the resulting fabric model to ballistic simulations is shown in the final part.