Open Access

Timo Schweiger, Jörg Lienhard, Hannes Grimm-Strele, Stefan Hiermaier

• For predicting the strain rate dependent failure of short fiber reinforced plastics (SFRP) a two-phase simulation model is developed using the finite element method and comparing the results to microscopic specimen tests for uniaxial tension under quasi-static (0.007/s) and dynamic loads (250/s). Experimentally the failure behavior of SFRP is observed to be strain rate dependent. The global strainFor predicting the strain rate dependent failure of short fiber reinforced plastics (SFRP) a two-phase simulation model is developed using the finite element method and comparing the results to microscopic specimen tests for uniaxial tension under quasi-static (0.007/s) and dynamic loads (250/s). Experimentally the failure behavior of SFRP is observed to be strain rate dependent. The global strain at failure and the absorbed energy increase with strain rate. Moreover, locally an influence of the strain rate on the amount of material involved in the deformation can be observed. The suggested model can represent these effects accurately. Also, the present micro-mechanical effects and their influence on the strain distribution are investigated by unit cell simulations. Thereby the material model of the fibers, the matrix, and the boundary layer are varied respectively. These reveal the important role of strain rate dependent decohesion leading to a correct representation of the plastically deformed volume. Consequently, the distortion energy density is evaluated and is found to be constant at failure for all strain rates.…