Effect of short fillers on inter-laminar fracture toughness of laminated composites

Abstract

In this study, short glass fibers with 1/4-inch average length and 16-μm diameter are uniformly dispersed into the epoxy system up to 3% volume fraction. Thus, prepared matrix system is used to fabricate 16 layered bidirectional glass fiber laminates by using hand layup technique and the effect of slender filler content on the mode-I fracture toughness of the laminated composites is investigated. Double cantilever beam specimens are machined from the cured laminates and fracture tests are performed under quasi-static loading conditions by following ASTM D5528-13 standards. Experiments suggest that filler reinforcement has marginal influence on the crack initiation toughness (GIi) of the laminates, however, the steady state and maximum energy release rates (GIc and GImax, respectively) are significantly improved in the case of filler reinforced laminates. The enhanced fracture characteristics due to reinforced fillers is attributed to the fiber bridging, short-fiber pull-out and crack branching.