How does the mechanical module work?

To run the mechanical module you first need to activate it:

Input.Simu.is_mechanics = 1;

This module takes as input the machine and the Maxwell stress and returns vibrations (as static and dynamic displacement). There are several ways to compute the vibrations, you need to set Input.Simu.type_mech_workflow to select the workflow:

Mechanical model workflows
Mechanical model workflows

The workflows are:

  • 0: Computes only the natural frequencies of the structure responsible for magnetic noise (outer rotor or outer stator). It is not possible to run the acoustic model after this workflow. It is meant for simulations that run only the mechanical module (e.g. run a sensitivity study on natural frequencies).
  • 1: Computes the natural frequencies, the Frequency Response Functions (FRF) with the analytical wave method and computes the radial displacement of the outer yoke by the Electromagnetic Vibration Synthesis (EVS) method.
  • 2: Computes the natural frequencies and then the radial displacement of the outer yoke analytically.
  • 3: Computes the radial displacement of the outer yoke by directly applying magnetic forces in a FEA structural model.
  • 4: Computes the FRF using wave excitation method on a FEA structural model and uses the EVS method to compute the overall radial displacements.
  • 5: Computes the FRF using tooth excitation method on a FEA structural model and uses the EVS method to compute the overall radial displacements.

When you have selected your workflow, there are up to three options that you need to set to choose how you want to compute the intermediate values. The input and output of the mechanical model are detailed in a dedicated article.

Select how to compute the natural frequencies

Some of the workflows (type_mech_workflow < 3) need to carry separately the natural frequencies computation to calculate the dynamic radial displacement of the yoke. To choose how you want to compute them, you need to set Input.Simu.type_nat_freq. The available options are:

  • 0: Analytical method
  • 1: FEA method (GetDp only in MANATEE v1.06.02)
  • 3: None (for type_mech_workflow > 2 only)

For type_mech_workflow > 2, computing the natural frequencies is optional.

After the natural frequency computation, one can enforce some additional natural frequencies according to ExpModes, ExpFreq and ExpDamp or tune the existing ones with multiplicative coefficients with Input.Simu.is_tune_natfreq.

Enforce or compute the FRF

For the workflows 1, 4 or 5, you can choose between enforcing the Frequency Response Functions (FRF) or computing it:

Input.Simu.is_load_FRF=0;%Compute the FRF, 1 load the FRF

If you want to load your FRF, you can follow the procedure according to the method of computation of FRF:

Select the FEA software

Finally, for type_mech_workflow > 2, you need to select the FEA software you want to use:

Input.Simu.type_FEA_model   %0 GetDp
                            %1 OptiStruct (not available yet in MANATEE v1.06.02)
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