Papers by Author: Sun Yi

Abstract: The relation between material’s cyclic plastic behavior and fatigue crack growth is investigated. The present model is proposed on the dislocation-free zone (DFZ) theory. A cohesive zone theory is developed to determine the stress field of the DFZ and the value of J-integer under cyclic loading. The crack growth criterion is proposed based on J-integral. The calculated curve of fatigue crack growth rate da/dN is agreement with the general propagation pattern and the predicted threshold accords with the experiment threshold well. It is found that the near threshold characteristics are most determined by the cyclic deformation behavior of the material. The relation between fatigue crack growth threshold and material’s cyclic hardening behavior is discussed.