Finite deformation analysis of cyclic elastoplastic crack-tip fields and implications for fatigue fracture

Finite-element large deformation analysis of the cracked strain-hardening elastoplastic solid under cyclic loading was performed. Only moderate quantitative changes, but not essential distinctions, were found in the near tip stress fields, if compared with the perfectly-plastic material. On the other hand, with regard to deformations, strain-hardening constitutive behaviour permits the formation of the localised slip bands in the fatigue crack tip. This affects the strain field shape and the rates of plastic strain accumulation in certain locations. The implications of the simulation results for criteria of fatigue crack growth are discussed focusing on the role of loading regime (amplitude and overloads) on crack propagation rate.