4. Implemented in Code_Aster

The treatment of the base sector is identical to that of the substructures in classical substructuring. It involves the operators CALC_MODES [U4.52.02], DEFI_INTERF_DYNA [U4.64.01], and DEFI_BASE_MODALE [U4.64.02].

The natural modes of the cyclic symmetric structure are calculated by the operator MODE_ITER_CYCL [U4.52.05] as a function of the projection base of the base sector previously defined and the number of sectors of the complete structure.

The retrieval of the results on a physical basis is identical to the classical substructuring. It involves the operator REST_SOUS_STRUC [U4.63.32] and possibly the operator DEFI_SQUELETTE [U4.24.01].