J-integral Evaluation from Displacement Fields around Crack Tip Measured by Digital Image Correlation

Abstract

In this paper, a method for evaluating J-integral for displacement fields obtained by digital image correlation (DIC) is proposed. First, the displacement gradient and strain are determined from the displacement using a least squares method on the domain of integration. Next, the stress components are determined from the strain using the Newton-Raphson method and material properties. Finally, the J-integral value is determined by the numerical integration on the domain of integration. The usefulness of this evaluation method is verified by applying this method to the displacement field obtained from the elasticplastic finite element analysis, and by applying to the experimental displacement field obtained by DIC.