MICROSCOPIC FAILURE MECHANISMS OF AN UNIDIRECTIONAL GLASS FIBER COMPOSITE

— The tensile failure mechanisms and the effects of manufacture flaws on the tensile behavior of an unidirectional composite (E-glass fiber/epoxy matrix) were investigated. Macroscopic failure processes were determined by an enhanced X-ray radiography technique and microstructural changes analysed by both optical and scanning electron microscopy. An axisymmetric finite element model was developed for analysing the microstress distributions in the composite containing broken fibers in order to determine the effect of local fiber volume fraction on the local failure process. Finally, the measurement of the volume fraction distribution of fiber misalignment was carried out and a simple analytical model was proposed to interpret the fiber misalignment effect. A correlation between the fiber misalignment distribution in the specimens and their tensile strengths was obtained statistically.