Fatigue damage mechanisms in carbon textile reinforced microfibrils cellulose modified epoxy

The experimental study aimed to understand the effects of micro-fibrillated cellulose (MFC) modified epoxy resin on the damage evolution of unnotched and notched (open hole) carbon plain weave textile composites, during tensile quasi-static and fatigue loadings. The initiation and propagation of the damage was studied assisting the tests with a high speed digital camera for measurement of the full field strain by the digital image correlation technique (DIC). The damage was observed by X-ray micro computed tomography (micro-CT). The hybridization of the matrix allowed an improved damage tolerance of the composite leading to increase of the quasi-static tensile strength and extension of the fatigue life. The enhanced performance was connected to the bridging effect of cellulose microfibrils preventing or delaying the cracks propagation in the matrix and along the fibers interface.