How to run a sensitivity study on natural frequencies?

Objectives

This article shows how to use MANATEE software to study the effect of natural frequency variations on the acoustic noise due to magnetic forces in electrical machines.

Principle

Such a study could be run manually using the sensitivity study mode of MANATEE, but it is interesting to have this sensitivity study automated to run robust vibroacoustic optimization of electrical machines. First the most important structural modes are identified in the vibroacoustic response, then a small variation of the associated natural frequency is applied and the resulting noise variation at nominal speed and at variable speed is calculated.

The maximum noise variation cumulating worse natural frequency variations at nominal speed and at variable speed is respectively stored in

Output.Acoustics.delta_LwrA

and

Output.Acoustics.delta_LwrA_max

Scripting implementation

The sensitivity study can be run manually in command line with

run_sensitivity_natfreq

Alternatively this analysis can be launched automatically at the end of the calculation with

Input.Simu.type_natfreq_sensitivity =1

The maximum number of modes to account is specified with

Input.Simu.Nmax_modes =3

A +/-5% variation of natural frequency is specified with

Input.Simu.delta_freqnat=5/100;

GUI implementation

TBC

See also

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