The development of energy efficient electrical machines requires accurate knowledge of the magnetic material behavior, i.e., iron loss components and magnetizability, already in the design stage. In addition, knowledge on the magnetic property deterioration due to induced residual stresses occurring during the manufacturing as well as due to applied mechanical stresses during the operation of the electrical machine is indispensable for the contemporary machine-design.In general, the modeling can be approached at different length scales, i.e., from quantum mechanics at the atomic level and micromagnetics at the sub-micrometer length scale to continuum modeling at the ultra-millimeter scale. The difficulty to apply micromag- netic approaches in the numerical simulation of electrical machines is given both, by the tremendous need of computational effort as well as the difficulty to consider the inter- action with effects present at the macroscale such as, e.g., residual stresses or non-local eddy currents.A more modern view of such aspects is to regard materials as multilevel structures, where structural features at all length scales play a significant role. Multiscale modeling is the field of solving such problems that have important features at multiple spatial and/or temporal scales. It allows calculating material properties on one level using information or models from other levels. In the light of this, this presentation will give an overview on the current modeling approaches applied at the Institute of Electrical Machines (IEM) for soft magnetic materials in the simulation of rotating electrical machines. Particular attention will be paid to the effect of residual as well as applied mechanical stress on the magnetic behavior occurring at the various steps of machine manufacturing and during machine operation.Selected References[1] N. Leuning, S. Steentjes, M. Schulte, W. Bleck, and K. Hameyer, ”Effect of elastic and plastic tensile mechanical loading on the magnetic properties of NGO elec- trical steel,” Journal of Magnetism and Magnetic Materials, vol. 417, pp. 42-48, November 2016.[2] S. Elfgen, S. Steentjes, S. B¨ohmer, D. Franck, and K. Hameyer, ”Continuous Local Material Model for Cut Edge Effects in Soft Magnetic Materials,” IEEE Transac- tions on Magnetics, vol. 52, no. 5, pp. 1-4, May 2016.[3] N. Leuning, S. Steentjes, M. Schulte, W. Bleck, and K. Hameyer, ”Effect of Mate- rial Processing and Imposed Mechanical Stress on the Magnetic, Mechanical, and Microstructural Properties of High-Silicon Electrical Steel,” steel research interna-tional, to appear, 2016.
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