A novel notch classification model for stress gradient-based fatigue life prediction under low and high cycle fatigue loading

In this work, a novel notch classification approach that considers the notch effects is developed. The classification of notches is implemented based on the stress gradient along the most critical path, defining the stress field diameter that quantifies the localized fatigue damage of the component. Then, a modified field intensity fatigue life prediction model using the developed notch classification is proposed. To evaluate the prediction capability of the proposed method, life predictions for various notch types of Inconel 718, Stainless steel 304 and 316H are carried out. For high temperature low cycle fatigue tests, the proposed model keeps the prediction accuracy of notched components falling within the scatter band of 2 times. Furthermore, the model also demonstrates satisfactory life prediction capabilities for high cycle fatigue. Finally, a scheme for predicting S-N curves of notched specimen is presented and validated.