Biaxial stress effects on the elastic-plastic crack-tip displacement fields

A plane stress, finite element analysis of the monotonic loading of a Mode I stationary crack under small scale yielding using a boundary layer approach is presented. A small-strain,J 2 plasticity theory is used in conjunction with a linear hardening material model. The effects due to the inclusion of the non-singular elastic T-stress in the asymptotic boundary conditions on the elastic-plastic fields near the tip are investigated. This parameter, which accounts for the inherent biaxial stress state at a crack tip, is found to control extension and state of deformation of the plastic zone. The full-field numerical solutions are also used to simulate moirè interferometric fringe patterns in order to assess earlier detailed experimental observations.