As a machining technology, welding can cause serious accidents by overloading or operation mistakes. Through analyzing the causes of various welding accidents, we found that the major cause for damage imposed after welding parts are loaded is the fracture of materials. Therefore, studying the influence of welding residual stress on the fracture property of materials is of great significance. This paper applied the digital image correlation technique to study the fracture property of welding parts under the influence of welding residual stress. In addition, standard parts and welding parts were selected to carry out a contrast experiment. Room temperature tensile tests were performed on both standard parts and test pieces after residual stress measurement. Using displacement field and strain field data obtained through VIC-2D software, the stress intensity factor around the crack tip of each specimen under the conditions of small load was calculated and corresponding analysis was carried out.
Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.