Computer simulation of cleavage fracture surface morphologies in steel plates

Abstract

A computer simulation model has been developed to reproduce brittle fracture surface morphologies. Local stress intensity factor along a propagating crack front is calculated considering the fracture surface irregularity and crack front non-straightness. Shear stress exerted at fracture surface steps and crack closure stress by uncracked ligament are also taken into consideration in calculating the local stress intensity factor. The local stress intensity factor is compared with assumed critical value to judge if a crack propagate or arrests at each crack front location. The model was found to reproduce chevron markings and shear-lips, both of which are typical of cleavage fracture in steels. The present model was applied to wide-plate crack arrest test with temperature-gradient. Changes of fracture surface morphologies and arrest crack length were well reproduced by the present model.