Fatigue modeling of short fiber reinforced composites with ductile matrix under cyclic loading

The micromechanical fatigue damage model in this work is based on a statistical microscopic damage law. Microscopic damage in short fiber reinforced composite are described by fiber failure and fiber/matrix interfacial debonding. Numerical methods are implemented to predict the fiber failure and failure in the fiber/matrix interface layer. Predictions of these types of failures have been applied to determine damages in each loading cycle. The work has been simulated adopting the concept of 3D unit cell models. The Weibull damage law is used to predict the microscopic damage behavior of composites taking into account the fiber volume fractions and orientation of fibers (0° and 90°) in the composite. By comparing the simulation with the experimental stress–strain curves for tension, the Weibull damage parameters are determined. Using these damage parameters a mesoscopic model of polymer matrix composites (PMCs) reinforced with 8.1 vol.% glass fibers including the effect of fiber-clusters is developed and the damage during cyclic loading is predicted. Good agreement is found for the reduction of the effective Young’s modulus due to damage between experiment and the simulation using the proposed fatigue model.