Prediction of tensile strength of discontinuous carbon fiber/polypropylene composite with fiber orientation distribution

This study proposes the layer-wise method (LWM) as a new approach for predicting the tensile strength of discontinuous fiber-reinforced composites that have arbitrary fiber orientation angles. The LWM assumes the discontinuous fiber-reinforced composites are identical to laminates that are composed of unidirectional fiber-reinforced plies and have the same distribution of fiber angles over the entire laminate. We applied the LWM to discontinuous carbon fiber polypropylene composites and evaluated the effect of fiber length on tensile strength and fracture mode. Simulated results agreed well with those of experiments. In addition, we proposed a simple analytical model based on micromechanics. This analytical model can correctly evaluate the strength and the fracture mode as effectively as the LWM. We also compared these models with a rule of mixture considering the failure criterion of fiber breakage and examined the limitation of the rule of mixture in predicting composite strength.