Mesoscale Simulations of High-velocity Impact on Plain-weave and 3-D Weave S-2 Glass Targets

Mesoscale models have been successfully used to simulate impact on fabrics and composites at ordnance velocities. There are many advantages of the mesoscale models: 1) individual components of the model (e.g. yarns) can be easily tested to check if they capture the important physics of the problem, 2) the components of the model often have simple material models (e.g. a yarn is often linear elastic up to failure), and 3) a multi-tier validation with material and ballistics tests at meso- and macroscale levels can be performed. The authors have successfully developed mesoscale models for a glass fiber reinforced composite (S-2 glass fiber with epoxy resin) that were validated by unconventional composite tests (e.g., torsion, out-of-plane delamination). In this paper the models are exercised at impact velocities ranging from 2 to 5 km/s. The original material models have simple constitutive laws (linear-elastic and elasto-plastic) that, in principle, have limited validity for hypervelocity impact. Therefore, modifications are made to better model the high-rate behavior of the epoxy resin matrix. The simulation results capture complicated damage mechanisms that might provide insight into future experimental data.