Structural dynamic material damping of laminated iron cores of electrical machines

Precise mechanical material models are essential for modeling the acoustic behavior of electric drives, especially for the laminated stator and rotor core. In this context, modeling the material damping plays a decisive role. Experimental modal analyses performed on a prototype are often needed to model the damping. The results of such measurements cannot be applied to or used for prediction for electrical machines according to the state of the art. Furthermore, the measurements show that in addition to the stiffness properties of a laminated iron core, the damping properties are also direction-dependent due to the structure of the sheet lamination. In this paper, a material-specific damping model is derived based on an analytical homogenization. As shown by measurements for an exemplary laminated stator core, the directional dependence of the material damping can be described with this model. The model can also be applied to and used for prediction for other machines.