Tensile strength prediction and model validation of anisotropic composite laminates with open holes

A general and semi-empirical model was developed to predict the tensile strength of multidirectional composite laminates with open-holes using the finite fracture mechanics method. Both stress-based and energy-based failure criteria were used to predict failure in this model. The ply elastic constants, the laminate unnotched strength and the fracture toughness of 0° plies were the only material properties required by the model. The relation between fracture toughness of multidirectional composite laminate and that of 0° plies was established based on linear fracture mechanics. The strength of an open-hole composite laminate with any fiber dominated lay-ups was predicted. The model was validated by comparing its prediction results with test data of open-hole composite laminates. The maximum predicting error is 9.7%. The model was also compared with point stress method and average stress method and results show that the present model provides more accurate predictions than the traditronal length method.