Crack Paths 2006

Figure 6. The complete triangulation of the perforated structure (without and with the

triangular surface mesh displayed).

5. D U P L I C A T ITN GH EC R A CFKA C E S

Before the final cracked structure is complete, the cracks themselves have to be inserted into

the perforated structure. Since the cracks must be able to generate new boundary faces, they

are generated by a duplication of the initial crack faces. The procedure simply makes exact

copies of the initial crack faces. The faces of each pair are then moved slightly apart. It is

important to make sure that the normal of the two faces are such that they face each other.

Figure 7 illustrates the duplicated crack and the perforated structure before the merging

procedure.

Figure 7. The perforated structure and the duplicated crack face (without and with the

triangular surface mesh displayed).