2. Principle of the test

One should check that the node groups defined by the options ZONE_MAJ and TORE of DEFI_GROUP are correct (see the U4.22.01 documentation for the description of these two options). To perform this check, we will build the group expected by the geometric options available in DEFI_GROUP and we will compare its nodes with those contained in the group constructed by the option to be verified.

In fact, this is possible because the bottom of the crack is straight and therefore the geometric location of the nodes of the created group is always a cylinder built around the bottom whose radius we know a prima facie. We can therefore use CREA_GROUP_NO/OPTION =” ENV_CYLINDRE “of DEFI_GROUP to create the group of nodes contained in the cylinder.

To simplify the determination of the cylinder radius, option RAYON_TORE is used in PROPA_FISS (see the U4.82.11 documentation for the description of this option), which allows you to specify the radius of the update area. In the case of using an auxiliary grid and verifying the group created by ZONE_MAJ on the mesh of the structure (see modeling D), the radius of the cylinder is independent of that specified by option RAYON_TORE by being coincident with the radius of projection between the auxiliary grid and the mesh of the structure. In this case its value is equal to the sum of the imposed advance (\(1\mathit{mm}\)) and the radius of convergence specified by RAYON in PROPA_FISS (see doc U4.82.11 for the description of this option).

In any case, the determination of the expected group of nodes should be done in the same way as the algorithm used by PROPA_FISS (see documentation R7.02.13). We must therefore first determine the nodes contained in the cylinder. Then select all the elements that contain at least one of these nodes in their definition. The expected group of nodes is that formed by the nodes of the elements selected in this way.

In order to compare the lists of nodes contained in each group (expected group and group built by the option to be checked), fields are used at the nodes. For each group, a field is built at the nodes by assigning the value \(1.0\) to the nodes that are in the group and the value \(0.0\) to the other nodes. Then we calculate the node-by-node difference between the two fields and we get the node-by-node difference field. If both groups are the same, the difference field contains only zeros, which can be tested by verifying that the field’s maximum and minimum values are \(0.0\).