A continuum damage mechanics model for short fiber reinforced composites

Objective of the present study is the definition and implementation of a fatigue damage model for short fiber reinforced composites. The model is based on a linear elastic or viscoelastic base model The base model is enhanced by introducing a damage variable acting on the Young’s and shear moduli respectively. Failure of the material is assumed to be described by a Tsai-Hill type failure envelope. The damage evolution is assumed to be driven by the approach of a state point in strain space towards the failure envelope. A power-law formulation is derived for the damage evolution equation. The model is implemented as a user defined material subroutine into a commercial finite element program and validated against an experimental data base on an injection molded short glass fiber reinforced polyamide 6 material.