A phenomenological fatigue life prediction model of glass fiber reinforced polymer composites

In this paper, a macro phenomenological fatigue model is developed for the off-axis fatigue behavior of glass fiber reinforced polymer (GFRP) composite laminates. The residual stiffness method and strain failure criterion are used to characterize the brittle nature of fatigue damage evolution. This allows one to obtain a practical form of multiaxial fatigue model that takes into account of the non-linear effects of fiber orientation dependence, stress ratio dependence as well as the effect of loading frequency on the fatigue behavior of composite laminates. Parameters of the model are fitted out according to relative fatigue experiment data with specific lay-up under certain stress ratio and loading frequency. Fatigue life predictions are verified by different stress ratios and loading frequencies, and the results of the model show a good agreement with experimental data.