Improvements to Dry Fabric Modeling for Ballistic Mitigation Systems

The focus of this paper is on improving the modeling of dry fabric-based systems widely used in propulsion engine containment systems. Simulations of fabrics under impact using finite elements provide valuable insight into the mechanics of fabric behavior and its energy absorption characteristics. In our model, the fabric is treated as an equivalent continuum model composed of thin shell elements. The fabric is made of simple weave Kevlar registered 49 whose behavior is characterized using uniaxial quasi-static and high strain rate tension tests, picture frame tests and friction tests. The methodology is general enough to be used with any dry fabric. Test results are used to determine the parameters used in the constitutive and finite element models. The constitutive model is programmed as a user-defined material model in LS-DYNA. Details and results from finite element simulations of a suite of 26 high velocity ballistic test results are presented. Results show that the developed model provides very reasonable predictive capabilities.