NUMERICAL MODELLING OF CYCLIC STRESS-STRAIN FIELDS NEAR A CRACK TIP: THE ROLE OF STRAIN HARDENING

摘要

Finite-element large deformation analysis of the cracked strain-hardening elastoplastic solid under cyclicrnloading was performed. Minor quantitative changes, but not essential distinctions, were found in the near tiprnstress fields comparing the data corresponding to different hardening rules (isotropic, kinematic and mixed)rnwith the perfectly-plastic constitutive model. As regards the deformations, strain-hardening facilitatesrnformation of the localised slip bands near the crack tip, and this localisation of plasticity is strongly promotedrnby the kinematic component of the hardening. This causes accelerated accumulation of plastic strain in certainrnlocations. The implications of the results for fatigue crack growth are discussed.