Objective

Machine

This validation case simulates a simple steel tube (thin cylindrical shell), which can be seen as a stator without teeth and winding, or more interestingly as a rotor without magnets. MANATEE must correctly calculates the natural frequencies of both outer stator electrical machines, and outer rotor electrical machines. For outer rotor PMSM with surface magnets, the structure radiating acoustic noise is close from a cylinder. The cylinder used for experimental validation (Experimental Modal Analysis) is the following:

Stator without teeth and without winding

This cylinder has the following mechanical and geometric properties:

 E=69 GPa
 \mu=0.33
 D_{int}=90 mm
 D_{ext}=100 mm
 h=5 mm
 L=171.45 mm
 \rho = 2700 kg/m^{3}

Results

An experimental modal analysis is run on this structure and successfully compared to Manatee analytical model. Note that the cylinder is here in free-free boundary conditions, but MANATEE analytical model also accounts for mixed boundary conditions between free, simply-supported and clamped. The longitudinal modes (such as (2,1)) are also validated. These modes can generate vibration and noise but are also excited when the magnetic forces vary along the axis of the machine (case of skewing, or slot inclination).

Analytical and experimental comparison of natural frequencies

As all validation cases of MANATEE, this simulation project can be accessed and edited by MANATEE users, and is tested everyday automatically to check that the multiphysic models of MANATEE behave correctly even though software developments are ongoing.