Multi-scale model for linking collective behavior of short and long cracks to continuous average fatigue damage

A multi-scale model is developed in this study for linking collective behavior of short and long cracks to continuous average fatigue damage. By using the developed model, the average fatigue damage evolution can be evaluated through some parameters that reflect collective behavior of short and long cracks, while collective behavior of short and long cracks can be reflected from the measured continuous average fatigue damage evolution based on the effective stress concept. The effectiveness of the model is verified by comparing numerical results with experimental data. The comparative results show that the developed model can be used to study the metal fatigue failure mechanisms from both macro- and micro-scale viewpoint.