Modified mean-field formulations for the improved simulation of short fiber reinforced thermoplastics

The aim of the contribution is to introduce modified mean-field formulations for the improved simulation of short fiber reinforced thermoplastics. In the first part, the recently proposed second moment incremental formulation for the mean-field homogenization of elastic–plastic composites of Doghri et al. (2011) [1] is modified. A stress concentration factor is introduced, which enables an adequate consideration of stress and strain inhomogeneities in dependence of the fiber orientation. In the second part, special focus is put on the characteristic elastic–plastic behavior of thermoplastics. It is well known, that thermoplastics show a distinct dependence of the volumetric stress in their mechanical elastic–plastic behavior. To account for this dependency, the commonly in mean-field formulations integrated von-Mises plasticity model is replaced by a quadric yield formulation proposed by Kolling et al. (2005) [2]. Conclusive results are achieved with both formulations by comparing simulation and experimental results.