Mixed mode fracture analysis using generalized averaged strain energy density criterion for linear elastic materials

A modified energy-based model called the generalized averaged strain energy density (ASED) criterion is proposed to predict the mixed mode I/II fracture resistance of brittle and quasi-brittle materials. The proposed criterion takes into account the effect of T-stress in addition to the stress intensity factors KI and KII when calculating the strain energy density averaged in a control volume around the crack tip. The effect of T-stress on the mixed mode fracture resistance of materials is investigated by using the generalized ASED criterion and the generalized SED criterion. The results predicted by these criteria are compared with the experimental results reported in the literature from fracture tests conducted on the Brazilian disc specimens and the semi-circular bend specimens made of Harsin marble and Guiting limestone. It is shown that the theoretical estimates of the generalized ASED criterion are consistent very well with the experimental results. The theoretical results also show that the specimens having a negative T-stress require higher loads in order their averaged strain energy density around the crack tip attains its critical value.