A modified model for fatigue life prediction with stress gradient

Mechanical components are subjected to variable amplitude loads under operational conditions, leading to a stress concentration phenomenon that can create a high-stress gradient in the critical regions of these components. This high-stress gradient significantly influences the lifespan of mechanical components. In this research, considering the effect of the stress gradient, a stress gradient factor is proposed and subsequently incorporated into the SWT (Smith-Watson-Topper) parameter model. The modified model's efficiency and accuracy were validated using three categories of experimental data from notched components made of 7075-T651, 1Cr11Ni2W2MoV, and GH901 materials. It shows that the modified model provides superior life prediction outcomes.