Initiation Life Prediction Method for Defective Materials

Abstract

The objective of the present paper emphasizes the investigation of the fatigue strength of materials containing surface defects and the development of a comprehensive analytical model, based on the response surface methodology (RSM), for correlating the interactive and higher-order influences of the various parameters such as the size of the defect, loading, and load ratio on the residual lifetime of these components. Firstly, a 3D-finite element analysis of a specimen containing a surface defect using ABAQUS commercial software is established to (i) simulate the distribution of the stress and the equivalent plastic deformation at the vicinity of the defect and (ii) to predict the fatigue life using the Smith-Watson-Topper SWT model. The non-linear kinematic hardening model, coupled with Lemaitre and Chaboche’s damage model, is used to characterize the material behavior. For this work, we used the experimental design technique to characterize the effects and the interactions between the defect size, the loading and the load ratio given by the Smith Watson Tooper model. Finally, using the surface response method, we have been able to develop an analytical model capable of predicting the fatigue response of steel 1045 considering defect size, loading and load ratio. Consequently, the finding results show a good agreement with those experimentally obtained.