Can MANATEE export the electromagnetic force data in frequency domain?

MANATEE electromagnetic model is in time/space domain. The projection tool of MANATEE calculates effective forces on both stator and rotor, and converts electromagnetic forces in the Fourier domain.

The nature of output magnetic forces depends on the structural model. Magnetic forces can be calculated as a magnetic force vector per node in Newton on structural FEA (e.g. coupling with Optistruct), or as a radial and tangential pressure applied on a semi-analytical cylindrical model of an outer rotor or outer stator.

For the semi-analytical vibroacoustic model, magnetic pressures are available in the workspace as complex Fourier transform through the following quantities:

Output.Mechanics.XPradwr
Output.Mechanics.XPtanwr

These are matrices of harmonic radial (resp tangential) pressure waves in N/m^2. The matrix size is smaller than [Nt_totc/2, Na_totc/2] given by Shannon theorem because it has been cropped according to maximum circumferential wavenumber and maximum frequency given respectively by:

Input.Simu.Nmax_fft_orders_circ
Input.Simu.freq_max_spec

The vectors of time frequencies and space frequencies (circumferential wavenumbers) associated to harmonic pressure matrices are given by:

Output.Mechanics.freqs
Output.Mechanics.orders_circ

These magnetic force waves can be plot using post-processings such as plot_Fr_fft2. Alternatively magnetic force vectors can also be plotted in Fourier space using plot_Fteeth_machine_fft or in time domain with plot_Fteeth_machine post processings.

These post processing are useful to identify the radial and tangential Maxwell force interactions in magnetic vibration and noise generation of electric machines.

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