Objectives
This article shows how to apply a user-defined modal property in MANATEE software specialized in noise mitigation of electrical machines.
Principle
A specific natural frequency and damping of a particular modal shape can be enforced when using MANATEE semi analytic structural models. In this case, damping and natural frequencies of a specific cylindrical mode (m,n) can be enforced by the user.
GUI implementation
TBC
Scripting implementation
By default, the damping of all structural modes used by MANATEE is frozen to 2% by the following input value:
Input.Simu.ksi_damp = 2/100;
To perform a modal parameter enforcement, one must set
Input.Simu.is_force_natfreq = 1;The following script lines change the ovalization mode (2,0) natural frequency to 500 Hz and the associated damping to 1%, change the breathing mode (order 0) damping of the stator stack to 2.78% without changing the corresponding natural frequency, and change the mode (5,0) natural frequency to 4000 Hz without changing the damping:
Input.Simu.ExpModes=[[2 0];[0 0];[5 0]];
Input.Simu.ExpDamp=[1/100 2.78/100 NaN];
Input.Simu.ExpFreq=[500 NaN 4000];This feature of MANATEE allows you to check the influence of a structural redesign, or enforce your own modal parameters which can be based on FEA simulations or experimental modal analysis.
Plot commands
NA
Validation cases
NA
See also
- what can explain differences between MANATEE and test results
- how to import a user-defined modal basis (coming from FEA or experiments)
