Edge on Impact Simulations and Experiments

In the quest to understand damage and failure of ceramics in ballistic events, simplified experiments have been developed to benchmark behavior. One such experiment is known as edge on impact (EOI). In this experiment, an impactor strikes the edge of a thin square plate, and damage and cracking that occur on the free surface are captured in real time with high speed photography. If the material of interest is transparent, additional information regarding damage and wave mechanics within the sample can be discerned. Polarizers can be used to monitor stress wave propagation, and photography can record internal damage. This information serves as an excellent benchmark for validation of ceramic and glass constitutive models implemented in dynamic simulation codes. In this paper, recent progress towards predictive modeling of EOI is discussed. Time-dependent crack propagation and damage front evolution in silicon carbide (SiC) and aluminum oxynitride (AlON) ceramics are predicted using the Kayenta macroscopic constitutive model. Aspects regarding modeling material failure, variability, and volume scaling are noted. Mesoscale simulations of dynamic failure of anisotropic ceramic crystals facilitate determination of limit surfaces entering the macroscopic constitutive model, offsetting limited available experimental data.