Multi-resolution finite element models for simulation of the ballistic impact on non-crimped composite fabric packages

A multi-scale finite element model for the simulation of medium velocity ballistic impact on non-crimped laminated composite fabric packages has been developed in LS-DYNA. The targets are soft fabric structures of non-crimped fibre plies bonded together by polymeric filling. The model of each fibre ply is divided into farther and nearer to impact zones. The farther zone is a macro-level model of orthotropic homogeneous membrane, and the nearer zone is a mezzo level structure composed of narrow aramid strips and polymeric gaskets. Shell elements are used for all the structural components of the fibre ply. The macro-level models employs the material properties determined on the base of the finite element analysis of the micro-cube representing a small fragment of the fibre bundle. At mezzo level the material properties are modified by using a mezzo-cube, which represents the narrow strip and gasket together. The convergence of the narrow strips model is demonstrated. Simultaneously with the combined macro-mezzo level model of a ply two different macro-level models are investigated. Good agreement among the results provided by different models has been established by proper adjustment of erosion strain parameter on the base of reference results obtained at mezzo level.