Experimental and computational analyses on residual stress of composite plate using DIC and Hole-drilling methods based on Mohr's circle and considering the time effect

Due to residual stress effects in final parts, researchers have always been interested to measure residual stress in different structures as well as comparing and analysing different methods in order to increase the accuracy and select the best method to measure it in different conditions and materials. The hole-drilling by applying the rosette strain gauge is one of the most commonly used methods for measuring residual stress and besides, the use of digital image correlation (DIC) method is expanding because of its advantages in measuring residual stress. So, these two methods have been studied by researchers. In this study, the results of residual stress measurements on composite plate by the hole-drilling and DIC methods are compared, but employing the Mohr's circle in this comparison as an innovation is discussed to understand better this issue. Also, considering that the other researchers have usually paid attention to measure the residual stress immediately just after drilling in the hole-drilling method using the strain gauge. Thus, the effect of elapsed time on the residual stress measurement is investigated in the results application. In both of these methods, the residual stress is calculated based on the principles of calibration coefficient measurement and the finite element method (FEM).