Fatigue life prediction of multidirectional composite laminate

For T300/QY8911 carbon/epoxy composites,three kinds of typical tests were performed to obtain the fit curves for unidirectional laminate.Then according to the fatigue damage cumulative theory,a theory method to predict the fatigue life of multidirectional laminates was described based on the life model of the unidirectional laminate.By using the stiffness distribution theory,the fatigue life of composite laminate was predicted by equalizing the load to every unidirectional laminate.This method overcomes the disadvantages of traditional predict methods which depends on the ply sequences and forced forms.The effects of the interlaminar stresses and the coupling on the fatigue life of composite laminate are considered.It is demonstrated that the experimental results agree well with the theoretical predictions.