Study on the effects of ultrasonic impact treatment on the local mechanical properties of welded joints based on the digital image correlation

In this study, UIT was used to strengthen the local mechanical properties of welded joints, and the influence of UIT on the local mechanical properties of welded joints was analyzed by 3D-DIC technology. At the same time, the mechanism of UIT on the microstructure and properties of welded joints was revealed by microstructure observation. By measuring the full-field strain process of the welded joint after UIT under uniaxial tensile load, the curve of the strain in the local area with time is obtained. At the same time, the Ramberg-Osgood equation and Conside`re criterion are used to fit the material constitutive relationship at each point in the local area. The results show that UIT significantly improves the yield strength of the WM and the tensile strength of the BM. This study provides technical and theoretical support for the preparation of high-quality welded joints by UIT technology.