Benchmark solution
=====================


Calculation method
-----------------

The infinitely rigid bearings and the absence of rotation of the shaft make it possible to perform a direct calculation with *Code_Aster* of the first natural modes of the massive-bearing-rotor structure which will serve as a reference for the substructured calculation in *Code_Aster*.

The validation of the consideration, by substructuring, of a generalized mass in a calculation of tree lines in *Code_Aster* will consist in comparing the natural frequencies obtained by a direct calculation and by a substructured calculation (substructuring of the Craig-Bampton type).

Efforts will also be made to validate each of the rotor-bearing and solid substructures separately.

In addition to the comparison between global calculation and substructured calculation in *Code_Aster*, we also validate the results with respect to those of CADYRO [:ref:`1 <1>`].


Reference quantities and results
------------------------

*Code_Aster* results give both mode frequencies and modal deformations. Only the frequencies are actually tested.


References
----------


1. CADYRO, finite element software intended to predict the dynamic behavior of rotors under bending validation file — note HP-61/94/049/B.