Determination of SIFs, crack-tip coordinates and crack angle of anisotropic materials

ABSTRACT This paper investigates the accuracy of a numerical method incorporating an image‐correlation experiment for finding the crack‐tip coordinates, the axes of the measurement and the mixed‐mode stress intensity factors (SIFs) of anisotropic materials. Finite element and experimental simulations in this paper indicate that the proposed linear search method incorporating Powell's method is considerably stable for finding the unknown crack‐tip coordinates and measurement axes, even though the initial input is far away from the actual data. Moreover, the displacement field very near the crack tip is not necessary. In the experimental validation, the maximum SIF error of the image‐correlation experiment is about 9%, which should be acceptable for the mixed‐mode fracture problems.