Weld Bead Distortion of Thin-Plate Using Weak Digital Image Correlation Method

Currently, the primary method used to investigate weld bead distortions is based on finite element prediction. However, in this paper, we proposed a three-dimensional optical method based on weak digital image correlation technology to track the dynamic distortion of the weld bead throughout the welding and cooling process. An experimental investigation demonstrated that the weld bead zone was distorted into a dish shape during the welding process and changed into a saddle shape after cooling down. In the weld bead, the out-of-plate distortion was significantly larger than the in-plate distortion, and the longitudinal plastic strain distribution was small and uniform, whereas the transverse strain was larger. This optical experimental method could be useful in the validation of numerical models in the welding process and important to research on welding distortions.