High- and low-cycle tensile fatigue of all-carbon hybrid quasi-isotropic laminate

Is the pseudo-ductile quasi-static tensile behaviour of all-carbon hybrid composites retained under fatigue loading? This paper addresses this question by examining the low-cycle tensile-tensile fatigue behaviour of a unidirectional carbon laminate and the high cycle fatigue behaviour of an all-carbon fibre hybrid quasi isotropic laminate. The low-cycle fatigue, monitored with the acoustic emission recordings, indicates that the damage pattern observed during the first cycle is maintained in subsequent cycles, albeit with reduced intensity than the initial damage. The high cycle tensile-tensile fatigue performance of an all-carbon fibre hybrid quasi-isotropic laminate revealed that its load-carrying ability is retained for load levels below the pseudo-ductile regime, while it is not beyond the limit of elastic response. Conversely, the all-carbon hybrid composite maintains its load-carrying ability during strain-controlled fatigue in the pseudo-ductile regime, albeit with a lower stiffness