Notch Behavior of Components Under the Stress-Controlled Creep-Fatigue Condition: Weakening or Strengthening?

Notch-related weakening and strengthening behavior under creep-fatigue conditions was studied in terms of the elastic-viscoplasticity finite-element method (FEM). A coupled damage analysis, i.e., the skeletal point method for creep damage evaluation coupled with the equivalent strain range method for fatigue damage, was employed in the notch effect evaluation. The results revealed that, under the short holding time condition, a weakening behavior was observed for the notch, while a strengthening effect was detected with the increase of holding time. The difference could be ascribed to the creep damage contribution in the holding stage. The influence of stress concentration factor (SCF), stress ratio, and the maximum stress was strongly dependent on the competition of creep and fatigue mechanism.