Fatigue damage accumulation in carbon/epoxy laminated composites

The precise prediction of fatigue damage progress and fatigue life in laminated composites has been always a concern to designers. The present work is focused on the fatigue damage mechanisms and damage accumulation rate in laminated composites. Results showed that the dominant damage mechanism depends on the applied stress and total delamination only observed under the cyclic stress of less than 0.7σUTS. Under high cyclic stress, transverse cracks in 45° ply appear and its density rapidly increases to the characteristic damage state (CDS). The obtained results showed that high-stress peaks (HSP) have remarkable effect on the fatigue life and predictions based on Palmgren–Miner’s rule showed considerable deviations from experimental results, whereas the new cumulative damage model presented in this work provided acceptable consistency with experimental results in the entire range of applied stress.