Characterizing and Predicting the Effects of Weave Geometry on Mode I Fracture Toughness of Composites

Abstract

Characterization of Mode I interlaminar fracture toughness, GI, of unidirectional composite materials is well understood and standardized in ASTM standard D5528. However, many composite structures are made of woven fabrics. Knowledge of the effects that woven fabrics have on GI is lacking. An approach based on the double cantilever beam test was developed in this work for characterizing the fracture performance of non-woven and woven composites. Weaves were all manufactured inhouse for better control over their geometry. The effect of several architectural factors on GI were investigated, such as fibre orientation, yarn width, yarn thickness and stacking configurations of weaves. Results showed that for weaves, GI was mostly affected by the bifurcation of the delamination front around yarns and by subsequent yarn bridging. The framework for empirical models was proposed for describing fibre bridging and the effects of weaves on GI.