Determination of notch stress intensity factors for V-notched specimens under mode I loading using the 3D-Digital image correlation and strain energy approach

Abstract

In this paper, the fracture behaviour of Single Edge Notched Tension Specimen (SENT) is investigated by using the three-dimensional digital image correlation (3D-DIC) method and the mode I notch stress intensity factors (NSIFs) for the SENT specimen is derived. Initially, the concept of NSIFs and different experimental methods are reviewed. This is followed by a review of the theory of the DIC method. Then, the step-by-step process for setting up a 3D-DIC full-field experimental system for the SENT specimens tested is described. In the experiments, the SENT specimens were tested with pinned and clamped boundary conditions (BCs) and different notch initial opening angles. Furthermore, the analytical stress fields around the sharp V-notches are presented. Combining with the strain energy approach (SEA), the experimental strain fields are analysed to calculate the mode I NSIFs. Moreover, the presented numerical mode I NSIF values for the SENT model are validated by the available results in the literature. Finally, the experimental results obtained from the 3D-DIC method are compared with the numerical results from finite element analysis (FEA) to verify the feasibility and accuracy of the 3D-DIC method. The effect of different BCs of pinned and clamped ends is discussed.