Direction of crack growth in fibrous composites

A model for predicting the direction of crack growth in resin matrix composite materials is presented. The model is based upon the normal stress and the anisotropic tensile strength on arbitrary planes about the tip of a crack. The model is incorporated into a finite element solution which predicts energy release rates in addition to the direction of crack growth. Results are obtained for cracks in unidirectional off-axis slotted tensile coupons. Comparisons are made with other theories and experimental results.