Interlaminar Crack Propagation in CFRP: Effects of Temperature and Loading Conditions on Fracture Morphology and Toughness

摘要

This paper presents a survey of fraclographic features associated with interlaminar failure of HTA/6376C carbon fiber/epoxy laminates. The intcrlaminar toughness and fracture morphology are investigated for effects of fatigue and static loading at elevated temperatures. In particular, Mode II loading conditions are investigated. Special emphasis is on initiation of matrix rollers and striations, two features indicative of Mode II fatigue failure. The initial mechanisms for delamination in this material under static and fatigue loading were found to be the same; the development of angled cracks ahead of the crack front, initiating from the fiber/matrix interface. Subsequent growth of the delamination was dependant on the loading conditions; under static loading shear cusps developed and coalesced whilst under cyclic loading increased plasticity led to development of matrix rollers. Fatigue striations observed in the fiber imprints were also found to initiate from the fiber/matrix interface cracks. The morphology of the striations, however, depended on the magnitude of the fatigue loading.