Fracture Analysis of Cracks in Orthotropic Materials Using ANSYS®
A methodology for performing two and three-dimensional fracture analyses in orthotropic materials using ANSYS software (“ANSYS”) is presented. The methodology makes use of analytically known crack tip fields in orthotropic materials and is implemented into a general purpose ANSYS macro. The ANSYS analysis, which takes into account the material orthotropy is performed in a regular manner by including the quarter point elements near the crack front. Then, in the post-processing module, the developed macro is run to associate the crack tip displacements with the orthotropic crack tip displacement fields to compute the mixed-mode stress intensity factors. Numerical examples are also presented that demonstrate application and validation of the procedure. These examples include an edge crack in an orthotropic strip and a surface crack in a transversely isotropic plate. The results show how the orthotropic fracture results may differ from those of isotropic fracture analysis. It is also shown that this difference can be dramatically big when the stress analysis is done using the orthotropic properties, whereas the fracture calculations are performed considering the crack tip fields for a crack in an isotropic material.