13th International Conference on Fracture June 16–21, 2013, Beijing, China iteration is done. Crack geometry Inserted crack Admissible edge/crack intersections Figure 3. Simplification of a complex 2D crack geometry. The next stage is related to the “cutting” algorithm, the aim of this stage is to generate a suitable approximation of the subtraction boolean operation between the volumetric mesh and the crack surface mesh (see figure 1). However, on complex meshes, such operation is very difficult to be operated robustly (due to the numerical errors in the numerous required operations). In order to make this operation much more robust, the approach is based on an idea out-coming from the XFEM/levelset approach: the approximation of the crack surface will be restrained to the fine volumetric mesh topology. The algorithm 1 and the figure 2 give some details about the generation of the cracked surface mesh. In case of a very complex crack surface, an approximation will be obtained with such kind of algorithm (see figure 3), for very accurate cracked mesh generation the initial uncracked mesh must be accordingly refined near the crack surface. Since a convex surface is generated during each element splitting, the method is only valid for linear simplex elements (during the process non-convex elements will be automatically split in simplex sub-elements). -4-
RkJQdWJsaXNoZXIy MjM0NDE=