V-notch crack initiation by the coupled criterion considering plasticity

An extension of the coupled criterion (CC) of finite fracture mechanics is proposed in order to assess brittle crack initiation considering plasticity. The main change compared to the classical linear elastic approach consists in considering the plastic strain energy variation due to crack initiation. The proposed approach enables assessing quasi-brittle failure at singularities or stress concentrators in materials exhibiting plastic deformation. It is illustrated on V-notch steel specimens subjected to bending. If plastic deformation is disregarded, the CC underestimates the failure force compared to those measured experimentally. Considering plasticity yields a better representation of failure force variation as a function of the V-notch angle.