Deformation measurement around a high strain-gradient region using a digital image correlation method

Digital image correlation could provide deformation information of a specimen by processing two digital images captured before and after the deformation. In this study, a hybrid genetic algorithm, in which a simulated annealing mutation process and adaptive mechanisms are added to a real-parameter genetic algorithm, is used to search for the deformed images to obtain both the strain and displacement data simultaneously. This method is applied to obtain the strain in a high strain-gradient region around a hole in a plate under uniaxial tensile testing. These data are compared with those obtained by using a strain gauge to judge the quality of the obtained strain data. The result indicates that the strain in a high strain-gradient region could be reasonably determined by using the present method.