5. notes

The reference values are those obtained by Code_Aster when restoring the test case, which will therefore make it possible to subsequently verify the non-regression of the code during its evolution.

The results obtained for the reduced damping are very slightly different between models A and B. This is explained by the fact that modeling B, which uses a simplified representation of the beam, assumes that all the tubes have a strictly identical modal deformation: the common deformation is that of a tube chosen arbitrarily in the bundle. Modeling A, which uses the complete representation of the beam, takes into account the infinitesimal variations in deformation from one tube to another. It is therefore normal for very slight differences in results to appear.

In addition, the slight differences observed in the results highlight the advantage of using a simplified representation of the beam when there are set modes. The gain in calculation time is quite significant.