Cylindrical shell model


Manatee e-NVH sotware provides fast structural mechanics models for the rapid evaluation of vibration levels under electromagnetic excitations. These models are based on equivalent cylindrical shell models of the stator or rotor (depending on the external structure source of air-borne noise). For stator models, they include teeth stiffness & mass effects, while winding is only represented as additional mass. For external rotor PMSM, magnets are also assumed to only contribute as additional mass. Ideal boundary conditions (free-free for stators) are assumed.


During concept design phase of electrical machines, it is important to avoid structural resonances between main lamination modes and main magnetic forces. Electrical engineers can use these fast structural models to quickly evaluate vibration levels due to magnetic forces, and make a first ranking of different electrical machine topologies. This fast model can also be use to directly optimize a vibration level in dB instead of working at magnetic stress level.
For inner rotor machines, a Beam Element Model is also available for more accurate modelling of stator tooth bending effect and to take the circumferential forces into account.
In detailed design phase, once a detailed CAD model of the e-machine structural environment (e.g. housing, gearbox, etc) is available, calculations can be refined using Manatee 3D modal basis import feature.