Abstract
A method for predicting the fracture toughness of a given laminate of any stacking sequence on the basis of the fracture toughness values of the constituent plies is proposed. This method is combined with the finite fracture mechanics (FFM) model to predict the notched strengths of two kinds of quasi-isotropic laminates. Static tension tests are first carried out on specimens with a circular open hole for four different values of hole-diameter to specimen-width ratios, respectively. The quasi-isotropic laminates of different stacking sequences exhibited similar notch sensitivity. The FFM model predicted a slightly smaller value of notched strength, regardless of notch size, with the ply-based fracture toughness. It is shown that the accuracy of prediction using the FFM model can be improved by taking into account the energy due to local delimitation.
