An argument for a cycle-by-cycle propagation of fatigue cracks at small stress intensity ranges

摘要

A model is presented in which the plastic strains around a growing fatigue crack are discretized in the form of geometrically necessary dislocations. The model explains the existence of a threshold and the near threshold regime. It also explains the minimum value of striation spacing with decreasing ampli- tude of stress intensity. The model corresponds to a "cycle-cycle" crack growth at all amplitudes of stress.