u2.06.31 Gyroscopy modeling instructions

Summary:

Linear and non-linear modal or dynamic analyses of tree lines require the integration of the concept of gyroscopic damping. The analysis of a rotational speed transient (increase in speed or deceleration) requires, for its part, to integrate the concept of gyroscopic stiffness.

Dedicated rotating machine codes use a preferred axis for rotor modeling (\(Y\) for ROTORINSA, \(Z\) for CADYRO, etc.). In Code_Aster, it is possible, with some precautions in the data layout, to model a rotor with any axis of rotation. Once the axis of rotation is chosen, the positive direction along this axis is defined as being the usual trigonometric direction of rotation.

This user manual is an aid to the use of the gyroscopic damping and stiffness functionalities. It must allow it to carry out a coherent and correct calculation of rotating machines, regardless of the axis of rotation of the shaft line.

• 1. Gyroscopic damping and stiffness
  • 1.1. Characteristics of gyroscopy
  • 1.2. Calculation of gyroscopic matrices
  • 1.3. Use of gyroscopic matrices
• 2. Example of calculating shaft line with axis along X
• 3. Example of calculating a tree line with any axis
• 4. Bibliographical references