Loosely woven fabric model with viscoelastic crimped fibres for ballistic impact simulations

A computational micro-mechanical material model of loosely woven fabric for non-linear finite element impact simulations is presented in this work. The model is a mechanism incorporating the crimping of the fibres as well as the trellizing. The equilibrium of the mechanism allows the straightening of the fibres depending on the fibre tension. The contact force at the fibre crossover point determines the rotational friction dissipating a part of the impact energy. The stress–strain relationship is viscoelastic based on a three-element model. The failure of the fibres is strain rate dependent. The model is implemented as user defined subroutine in the transient finite element code LS-DYNA. The ballistic impact simulations with the model are in good agreement with the experimental results