Investigation of identification method of crack tip location for obtaining fracture toughness of dissimilar material interface using displacement data by DIC

Abstract

The objective of this study is to identify the crack tip location from the measured displacement of the bonded material surface around the crack tip obtained by Digital Image Correlation (DIC) method using the least-squares method with the theoretical displacement as a model function. The theoretical displacement around the crack tip position is considered as a subset. The residual sum of squares of the measured displacements obtained by DIC is calculated for each assumed crack tip position along the bonding interface. The coordinate with the smallest residual sum of squares is taken as the crack tip position. At the same time, the stress intensity factor is determined. In this study, to verify the proposed method, theoretical displacements were used as measured values to determine the residual sum of squares. As a result, the local minimum value of the residual sum of squares indicated the set crack tip position. At the same time, the stress intensity factor was obtained.