B modeling ============== Characteristics of modeling ----------------------------------- The shaft is modelled with girder POU_D_T elements regularly distributed at **constant circular section** with a diameter equal to the diameter of the rotor studied **in line with the initial node** of the element. In addition, discrete elements of the DIS_TR type are used for modeling the bearings. Characteristics of the mesh ---------------------------- Number and type of elements: 2000 SEG2 2 POI1 Number of knots: 2001 Tested sizes and results ------------------------------ The values of the first 12 frequencies when stopped and for rotation speed :math:`4000\mathrm{tr}/\mathrm{min}` are shown in the table below: +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |**Frequency Number**|**Rotation speed** **(** :math:`\mathrm{tr}/\mathrm{mn}` **)**|**Cadyro calculation with a variable-section tree** :math:`F` **(** :math:`\mathrm{Hz}` **)**|**Tolerance (%)**| +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |1 |0 |332.14 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |331.51 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |2 |0 |332.14 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |334.10 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |3 |0 |1193.81 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |1196.30 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |4 |0 |1193.81 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |1202.05 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |5 |0 |1607.19 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |1607.19 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |6 |0 |2291.51 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |2304.73 |2.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |7 |0 |2291.51 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |2312.08 |2.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |8 |0 |2512.22 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |2512.22 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |9 |0 |3160.39 |1.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |3160.39 |1.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |10 |0 |3520.23 |2.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |3516.43 |2.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |11 |0 |3520.23 |2.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |3524.02 |2.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ |12 |0 |4724.14 |2.0 | + +--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ | |4000 |4724.14 |2.0 | +--------------------+--------------------------------------------------------------+---------------------------------------------------------------------------------------------+-----------------+ **Table** 4.3-1 **: Natural frequencies obtained by QZ**