Fracture Toughness Evaluation for Brittle Polymers under Combined Tensile-shear Loading
Fast fracture is one of the major failure modes in brittle polymers. Generally, crack growth in these polymers may occur under combined tensile-shear loading. However, the fracture test data reported previously for some dental restorative resins can not be predicted by using the available fracture criteria. In this paper, a modified fracture criterion is used for estimating the fracture load for the mentioned resin samples. It is shown that by considering a more accurate description for the crack tip stresses and also by accounting for the craze zone effects in front of the crack tip, the modified criterion presents significantly better predictions for the fracture resistance in such brittle polymers.