Mesh sensitivity studies for mixed-mode two dimensional fracture problems using displacement correlation technique

The displacement correlation technique is still one of the most commonly used numerical methods to compute stress intensity factors using the finite element method. Depending on settings and values of parameters, some variation on the computed stress intensity factor can be yielded. Therefore, in this study, sensitivity studies were performed for two-dimensional cracks under mode-I and mixed-mode loadings that cover most of two-dimensional cracks encountered in practical applications. These problems are; mode-I central crack, mixed-mode inclined central crack, mode-I edge cracks, and mixed-mode inclined edge cracks. As the numerical tool, the finite element software ANSYSTM was used and its KCALCTM command was employed for calculation of stress intensity factors. The six problems were studied by developing macros that generate the models, solve them and perform post-processing of results automatically. The stress intensity factors computed from two different mesh models for different settings of parameters were compared with known analytical solutions. The two mesh models are ?Circular Zone Model? and ?KSCONTM Model?. The parameters considered for near-crack-tip mesh sensitivity studies are, numbers of elements in the circumferential direction, numbers of elements in the radial direction, sizes of elements along the crack faces, element size ratio in the radial direction and the size of first radial element in the crack zone. The corresponding sensitivity graphs were plotted to visually see the parameters which affect results the most. Conclusions were drawn by comparing the values obtained from two different mesh models with results from the literature and mesh parameter settings were recommended for accurate computation of stress intensity factors.