Load Sequence Effects on the Fatigue of Unnotched Composite Materials

A comprehensive version of a fatigue and residual strength degradation model previously developed by the authors is proposed. This theoretical model is capable of predicting the statistical distributions of the fatigue life and the residual strength as well as the effect of load sequence, under variable amplitude or spectrum loadings, on these distributions. The model has been verified by the use of existing test data on glass/epoxy laminates. It is shown that the correlation between the model and the test results is good.