A novel method for determining fatigue damage parameters

Fatigue fracture of metal materials is a common failure mode in engineering structures. Damage mechanics regards crack initiation as a progressive damage process, describing and conducting life estimates through the damage evolution equation. However, the parameters in the damage evolution equation need to be fitted according to the standard experimental data. This process usually requires multi-parameter fitting, which involves complicated operation, large computational amount and vague physical meaning. To avoid these problems, based on the theoretical basis of damage mechanics, a new method to determine the parameters of damage evolution equation was proposed. According to the properties of damage evolution equation and the characteristics of S-N curves, a single parameter method, which employs single parameter to determine the damage evolution equation, was proposed using mathematical method. The proposed method avoids the disadvantage of multi-parameter fitting at the same time and improves the calculation accuracy and speed, which provides an alternative for engineering analysis. Finally, a concrete example is given to demonstrate the effect of the proposed method.