13 papers
Structured Neural Network Models for Anisotropic Magnetic Constitutive Laws
Dorian Zeilinger, Felix Engertsberger, Herbert Egger
High-performance electrical steel used for iron cores of power transformers and generators exhibits complex material behavior. While modeling and simulation of isotropic nonlinear…
Spectral isometries of unital -algebras
Matthew J. Colbrook, George Stepaniants
This paper provides a human digestion of a proof of the spectral isometry conjecture for -algebras found by GPT-6 Astra. We prove that every unital surjective complex-linear s…
A semi-smooth Newton method for efficient evaluation of the inverse hysteresis operator
Herbert Egger, Felix Engertsberger
We study the numerical evaluation of an energy-based vector hysteresis model and its incorporation into finite element simulations based on a vector potential formulation. The inhe…
Efficient evaluation of forward and inverse energy-based magnetic hysteresis operators
Herbert Egger, Felix Engertsberger, Andreas Schafelner
The energy-based vector hysteresis model of Francois-Lavet et al. establishes an implicit relation between magnetic fields and fluxes via internal magnetic polarizations which are…
On the vector potential formulation with an energy-based hysteresis model and its numerical solution
Herbert Egger, Felix Engertsberger
The accurate modelling and simulation of electric devices involving ferromagnetic materials requires the appropriate consideration of magnetic hysteresis. We discuss the systematic…
A semi-smooth Newton method for magnetic field problems with hysteresis
Herbert Egger, Felix Engertsberger
Ferromagnetic materials exhibit anisotropy, saturation, and hysteresis. We here study the incorporation of an incremental vector hysteresis model representing such complex behavior…
On energy consistent vector hysteresis operators
Herbert Egger, Felix Engertsberger, Lukas Domenig +2
Incremental models for magnetic vector hysteresis have been developed in previous works in accordance with basic principles of thermodynamics. In this paper, we present an equivale…
On nonlinear magnetic field solvers using local Quasi-Newton updates
Herbert Egger, Felix Engertsberger, Lukas Domenig +2
Fixed-point or Newton-methods are typically employed for the numerical solution of nonlinear systems arising from discretization of nonlinear magnetic field problems. We here discu…
On the convergence of higher order finite element methods for nonlinear magnetostatics
Herbert Egger, Felix Engertsberger, Bogdan Radu
The modeling of electric machines and power transformers typically involves systems of nonlinear magnetostatics or -quasistatics, and their efficient and accurate simulation is req…
A reduced scalar potential approach for magnetostatics avoiding the coenergy
Herbert Egger, Felix Engertsberger, Bogdan Radu
The numerical solution of problems in nonlinear magnetostatics is typically based on a variational formulation in terms of magnetic potentials, the discretization by finite element…
Global convergence of iterative solvers for problems of nonlinear magnetostatics
Herbert Egger, Felix Engertsberger, Bogdan Radu
We consider the convergence of iterative solvers for problems of nonlinear magnetostatics. Using the equivalence to an underlying minimization problem, we can establish global line…
Stability and convergence of the penalty formulation for nonlinear magnetostatics
Herbert Egger, Felix Engertsberger, Klaus Roppert
The magnetostatic field distribution in a nonlinear medium amounts to the unique minimizer of the magnetic coenergy over all fields that can be generated by the same current. This…
An efficient mixed finite element method for nonlinear magnetostatics and quasistatics
Herbert Egger, Felix Engertsberger, Bogdan Radu
We consider systems of nonlinear magnetostatics and quasistatics that typically arise in the modeling and simulation of electric machines. The nonlinear problems, eventually obtain…