Fatigue life prediction of pultruded E-glass/polyurethane composites

In this article, the tension-tension fatigue behavior of newly developed pultruded E-glass/polyurethane composites is characterized, and an improved model for fatigue life prediction including the effects of stress ratio, frequency, and mean stress as the testing parameters is proposed. The proposed non-dimensional analysis is in good agreement with the predictions of existing available fatigue data and present testing data. The model is consistent with the Goodman line relationship and has a clear physical meaning. The fatigue test data of E-glass/polyurethane composites are analyzed using the proposed model, and they are compared with other common E-glass fiber-reinforced plastic composites. It indicates that the E-glass/polyurethane composites are more fatigue sensitive but comparable to other fiber-reinforced plastic composites in their fatigue behaviors. The effects of stress ratio, frequency, and mean stress on fatigue life of E-glass/polyurethane composites are studied and discussed. The corresponding S-N curve and its bounds based on 95% confidence are provided for the pultruded E-glass/polyurethane composites. The present fatigue model can be used as a useful tool to characterize the effects of various parameters on the fatigue behavior of fiber-reinforced plastic composites, and it provides the fatigue life prediction for newly developed pultruded E-glass/polyurethane composites.