8. G modeling#
8.1. Characteristics of modeling#
The aim of this modeling is to globally validate the entire propagation procedure with cohesive elements. The method GEOMETRIQUE is therefore used by PROPA_FISS, alternately with the operations DETEC_COHESIF and PROPA_COHESIF, to respectively update the tangent level-set (and therefore the propagation front) and the normal level-set (and therefore the « possible » cracking surface). The bifurcation angle is determined by CALC_G (in FEM, mesh crack), and the cohesive elements are introduced into the model by the DEFI_CONTACT command.
8.2. Characteristics of the mesh#
An unstructured mesh is used, the initial crack being meshed. It has 16,632 elements of type TETRA4.
8.3. Tested sizes and results#
Two propagation steps are carried out, then the position of the propagation front is extracted at the end of this operation. The validation consists of a non-regression test on the position of this front. In order to reduce the number of tests, the maximum and minimum coordinates \(Y\) and \(Z\) are tested along the front.
\(\mathit{Propag.}i\) |
|
|
|
|
|
2 |
3.14 |
3.05 |
3.05 |
9.04 |
9.03 |
In figure, we represent a view of the deformation and of the stress field at the end of the second propagation step. The crack tends to straighten to propagate in a plane.
Figure 8.3-a : deformed and stress field