December 17, 2022

New FWF stand-alone project for Dr. Karl HOLLAUS

Dr. Karl HOLLAUS was granted an FWF stand-alone project for his proposal on Effective Material Transformation for Ferromagnetic Sheets EMT4FS (FWF grant P36395).

The computation of eddy currents (ECs) in laminated iron cores of electrical devices or in thin contacting ferromagnetic shielding sheets is of enormous importance. Detailed finite element (FE) models would yield extremely large equation systems (ESs) impossible to solve with reasonable computational effort. Accurate modeling of highly nonlinear and anisotropic materials with hysteresis is challenging.

Multiscale and homogenization methods are currently one of the best methods to simulate the ECs in thin sheets efficiently. However, strong field variations across a sheet makes the assembling of FE systems expensive especially in case of hysteresis. Homogenization replaces a given fine scale hetero-structure with a homogeneous one such that certain quantities, e.g. reaction fields and losses, remain approximately the same. A low frequency excitation induces ECs in laminated nonlinear magnetic and conducting media. A coarse-scale (homogeneous) model does not include ECs and is, counter-intuitively, magnetostatic, with an effective complex-valued BH-curve whose real and imaginary parts accurately represent active and reactive power in the sample. There are known methods where complex BH-curves were used in connection with hysteresis, but here they are introduced in the context of homogenization.

The aim of the project is to accurately compute ECs in thin highly nonlinear sheets and associated stray fields by novel methods requiring radically less FEs, that work with only a scalar potential at the best and avoid expensive FE system assembling. The project will be carried out by the principal investigator and doctoral candidates.

Karl Hollaus received his Ph.D. in 2001 from Graz University of Technology under supervision of Oszkár Bíró. In 2009 he joined the group of Joachim Schöberl at RWTH Aachen and later moved with him to TU Wien in 2010, where he is currently a research assistant.

The Institute of Analysis and Scientific Computing congratulates Karl on securing this research project!

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