Interfacial properties and fatigue behavior of carbon fiber epoxy laminate composites

Abstract

Abstract The study elucidated the relationship between the stacking sequence and physical properties, by investigating mechanical properties, fatigue life and the morphology, after fatigue fracture of carbon fiber/epoxy composites. The results show that the unidirectional carbon fiber laminate has the maximum tensile stress. Moreover, the laminate with ±45° plies can improve the tensile strain. The fatigue life of all specimens was shorter than 103 cycles under high cyclic stress level, and longer than 106 cycles under low cyclic stress level. Laminates with [908]s stacking sequence had the shortest fatigue life under high and low cyclic stress, while the unidirectional carbon fiber laminate had the highest fatigue life. A number of fatigue damage models, including delaminating, matrix cracking and fiber failure, have been identified by scanning electron microscopy (SEM). The SEM micrographs showed that the morphology on the cross section, after fatigue fracture, was significantly correlated to the stacking sequence.