Considering the Effect of Non-Propagating Cracks on Fatigue Limit Prediction in the Critical Distance Method Framework

Abstract

Although the material has developed micro-scale cracks, the micro-cracks stop propagating and transform into non-propagating cracks (NPCs) under fatigue limit loading. The movement of the crack tip position caused by the non-propagating crack will generate a small change in the notch geometry, which easily triggers the geometric size effect. Since the critical distance method focuses on evaluating the limit of fatigue in terms of the material’s cracking conditions, the present study attempted to develop a notched fatigue analysis model to consider the effect of non-propagating cracks on fatigue limit prediction in the critical distance method framework. The effectiveness and capability of the proposed model were demonstrated by the fatigue experimental data of Q345qD low carbon steel.

Keywords

• notch fatigue
• critical distance method
• non-propagating crack
• size effect