Numerical study of the microstructure induced uncertainty in the mechanical properties of short fibre reinforced polymers

This study focuses on the scatter in the mechanical properties in short fibre composites caused by uncertain fibre orientations. To interrelate the microstructural geometric and topological uncertainty with the material uncertainty on the macroscopic level, a numerical approach is utilized. Considering short fibre reinforced microstructures statistically described in terms of the probability distributions for the main stochastic variables such as fibre orientation, length, and density, statistically equivalent microstructural geometric models are generated using random number generation. The mechanical response of these microstructures is analysed in finite element analyses under different independent loading situations. The large-scale representative volume elements are subdivided for the evaluation into non independent stochastic volume elements. Like this the surrounding microstructure is included in the boundary conditions. A numerical homogenization analysis is applied on the statistic volume elements to evaluate effective macroscopic material parameters and their probability distributions. The results are correlated with the uncertainty of the input parameters.