Strain distribution and fatigue life estimation for steel plate weld joint low cycle fatigue based on DIC

Abstract Welded steel plates are widely used in several engineering applications. Usually, the material properties of the parent material are prior to the welded structure, which frequently causes the welding joint to fail due to fatigue. Predicting the fatigue life of a material is not a simple task, especially, when considering the welding joint with various constituents. In this study, a strain distribution for a steel plate weld joint was investigated using the digital image correlation technology to estimate the low cycle fatigue life. Using the reconstructed strain, a nonlinear model of strain was presented. Moreover, the rate change of strain was used as a fatigue failure criterion to predict the lifetime. The proposed model considers the strain-rules from two aspects: maximum value and change rate. With the information of the initial strain value, we can achieve the desired prediction for the fatigue life of the steel plate weld joint under the low cycle fatigue loading.