A Fracture Mechanics Study of a Compact Tension Specimen: Digital Image Correlation, Finite Element and Meshless Methods

Abstract

This study mainly aims to determine the stress intensity factor range (SIF) for a compact tension (CT) specimen under uniaxial tensile fatigue loading state. A 2D full-field optical technique, Digital Image Correlation (DIC), is used to acquire the experimental solution. Therefore, the deformation contour is measured for several crack growth lengths. In addition, SIF is experimentally characterized together with a numerical overdetermined algorithm for different crack lengths. Besides, the strain variation with respect to the notch tip is captured. The innovation of this study is the combination of an experimental DIC procedure with a numerical overdetermined algorithm. Moreover, to assess the performance of the proposed fracture model, the problem is resolved using advanced discretization techniques, such as the Finite Element Method (FEM) and the Meshless Radial Point Interpolation Method (RPIM). Thus, the cracked CT specimen is elasto-statically modeled using above-mentioned numerical approaches. Hence, the FEM model is analyzed with ABAQUS ©, allowing to compute the mode I SIF results for different crack lengths in addition to strain contours. Likewise, the foregoing procedure is repeated for the RPIM analysis and encouraging numerical results are achieved. The SIF is determined with a maximum energy release rate criterion in front of the crack tip in FEM study, while in RPIM study, it is calculated within the same overdetermined algorithm used in the DIC study. Overall, the experimental and numerical SIF results are compared with the reported solution (ASTM E647) exhibiting a reasonable agreement.