3. What are the cases treated?

Depending on the degrees of freedom carried by the nodes in the list of knots to be rigidified, we are in one of the following four scenarios. If we do not find ourselves in one of these cases, the code stops in a fatal error:

• Cases \(\mathrm{2DA}\) and \(\mathrm{2DB}\) correspond to « plane » or axisymmetric problems;

• Cases \(\mathrm{3DA}\) and \(\mathrm{3DB}\) correspond to 3D problems.

Case \(\mathrm{2DA}\) :

All the nodes in the list of nodes to be rigidified have degrees of freedom \(\mathit{DX}\) and \(\mathit{DY}\) and at least one of the nodes has \(\mathit{DRZ}\).

Case \(\mathrm{2DB}\) :

All the nodes in the list of knots to be rigidified have \(\mathit{DX}\), \(\mathit{DY}\) but they don’t have any step \(\mathit{DRX}\), \(\mathit{DRY}\), and \(\mathit{DZ}\).

Case \(\mathrm{3DA}\) :

All the nodes in the list of nodes to be rigidified have degrees of freedom \(\mathit{DX}\), \(\mathit{DY}\) and \(\mathit{DZ}\) and at least one of the nodes has \(\mathit{DRX}\), \(\mathit{DRY}\), or \(\mathit{DRZ}\).

Case \(\mathrm{3DB}\) :

All the nodes in the list of nodes to be rigid have \(\mathit{DX}\), \(\mathit{DY}\), \(\mathit{DZ}\) and there is no node in the list of nodes to be rigid that has degrees of freedom of rotation \(\mathit{DRX}\), \(\mathit{DRY}\), \(\mathit{DRZ}\).

Only cases \(\mathrm{2DB}\) and \(\mathrm{3DB}\) can currently be treated nonlinearly (TYPE_CHARGE =” SUIV “).