Papers by Wolfgang Rucker
Intelligent and Distributed Solving of Multiphysics Problems Coordinated by Software Agents - An Intelligent Approach for Decentralized Simulations
Proceedings of the 10th International Conference on Agents and Artificial Intelligence
The numerical solution of two-dimensional electromagnetic scattering problems with the boundary element method
1983 Antennas and Propagation Society International Symposium
Informatyka Automatyka Pomiary w Gospodarce i Ochronie Środowiska
Based on autonomous software agents capable of calculating individual numerical field problems, a... more Based on autonomous software agents capable of calculating individual numerical field problems, a distributed method for solving transient field problems is presented. The software agents are running on distributed resources connected via a network and represent a dynamic calculation environment. Communication and data exchange between multiple agents enables their collaboration and allows decisions based on distributed overall knowledge. As unique characteristics, no central unit influences the solution process at any time. The presented simulation example and its evaluated calculation process proves the method to benefit from redundant resources.
Motion in frequency domain for harmonic balance simulation of electrical machines
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
Purpose The high computational effort of steady-state simulations limits the optimization of elec... more Purpose The high computational effort of steady-state simulations limits the optimization of electrical machines. Stationary solvers calculate a fast but less accurate approximation without eddy-currents and hysteresis losses. The harmonic balance approach is known for efficient and accurate simulations of magnetic devices in the frequency domain. But it lacks an efficient method for the motion of the geometry. Design/methodology/approach The high computational effort of steady-state simulations limits the optimization of electrical machines. Stationary solvers calculate a fast but less accurate approximation without eddy-currents and hysteresis losses. The harmonic balance approach is known for efficient and accurate simulations of magnetic devices in the frequency domain. But it lacks an efficient method for the motion of the geometry. Findings The three-phase symmetry reduces the simulated geometry to the sixth part of one pole. The motion transforms to a frequency offset in the ...
Coupling of finite element method and integral formulation for vector Helmholtz equation
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
Purpose Considering the vector Helmholtz equation in three dimensions, this paper aims to present... more Purpose Considering the vector Helmholtz equation in three dimensions, this paper aims to present a novel approach for coupling the finite element method and a boundary integral formulation. It is demonstrated that the method is well-suited for many realistic three-dimensional problems in high-frequency engineering. Design/methodology/approach The formulation is based on partial solutions fulfilling the global boundary conditions and the iterative interaction between them. In comparison to other coupling formulation, this approach avoids the typical singularity in the integral kernels. The approach applies ideas from domain decomposition techniques and is implemented for a parallel calculation. Findings Using confirming elements for the trace space and default techniques to realize the infinite domain, no additional loss in accuracy is introduced compared to a monolithic finite element method approach. Furthermore, the degree of coupling between the finite element method and the int...
A Neural Network Based Recommendation System for Solvers and Preconditioners for Systems of Linear Equations
IEEE Transactions on Magnetics
Bemscat3D - a boundary element package for 3D time-harmonic scattering problems
Digest of the Fifth Biennial IEEE Conference on Electromagnetic Field Computation
ABSTRACT
Boundary elements method computations of 3D transient scattering from lossy dielectric objects
Digest of the Fifth Biennial IEEE Conference on Electromagnetic Field Computation
Design and simulation of the electromagnetic heating of a biological tissue
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
Purpose The purpose of this paper is to present the design and the numerical calculation of the e... more Purpose The purpose of this paper is to present the design and the numerical calculation of the electromagnetic heating system for the ablation therapy. Hence, the heating of the tumor cells must be processed very carefully to achieve a localized coagulative necrosis and to avoid too high temperatures inside the tissue. Design/methodology/approach The non-invasive method of the ablation therapy is implemented due to the inductive power transmission between the generator and implant. The ferromagnetic implant has a small size and can be placed intravenously into tumor cells. High-frequency driving currents are necessary to obtain high induced eddy currents within the ferromagnetic implant. Findings Finite element analysis has been used for the design and numerical calculation of the electromagnetic heating system. The electromagnetic analysis is done in the time domain due to the nonlinearity of the ferromagnetic implant. Magnetic fields are computed based on a magnetic vector potent...
Experimental evaluation of numerical errors for multi-physics coupling methods using disparate meshes
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
Purpose Multiphysics problems are solved either with monolithic or segregated approaches. For acc... more Purpose Multiphysics problems are solved either with monolithic or segregated approaches. For accomplishing contrary discretisation requirements of the physics, disparate meshes are essential. This paper is comparing experimental results of different interpolation methods for a segregated coupling with monolithic approaches, implemented using a global and a local nearest neighbour method. The results show the significant influence of discretisation for multiphysics simulation. Design/methodology/approach Applying disparate meshes to the monolithic as well as the segregated calculation of finite element problems and evaluating the related numerical error is content of the contribution. This is done by an experimental evaluation of a source and a material coupling applied to a multiphysics problem. After an introduction to the topic, the evaluated multiphysics model is described based on two bidirectional coupled problems and its finite element representation. Afterwards, the consider...
Harmonic balanced Jiles-Atherton hysteresis implementation for finite element simulation
COMPEL - The international journal for computation and mathematics in electrical and electronic engineering
Purpose The high calculation effort for accurate material loss simulation prevents its observatio... more Purpose The high calculation effort for accurate material loss simulation prevents its observation in most magnetic devices. This paper aims at reducing this effort for time periodic applications and so for the steady state of such devices. Design/methodology/approach The vectorized Jiles-Atherton hysteresis model is chosen for the accurate material losses calculation. It is transformed in the frequency domain and coupled with a harmonic balanced finite element solver. The beneficial Jacobian matrix of the material model in the frequency domain is assembled based on Fourier transforms of the Jacobian matrix in the time domain. A three-phase transformer is simulated to verify this method and to examine the multi-harmonic coupling. Findings A fast method to calculate the linearization of non-trivial material models in the frequency domain is shown. The inter-harmonic coupling is moderate, and so, a separated harmonic balanced solver is favored. The additional calculation effort compar...
Numerical Foundations, Integral Methods and Applications
The BEM-FEM coupling method for the solution of three dimensional nonlinear shielding problems of low frequency fields considering TEAM problem 21
Electr Eng, 1997
Computing and Visualization in Science, Nov 24, 2005
Applications of boundary element methods (BEM) to the solution of static field problems in electr... more Applications of boundary element methods (BEM) to the solution of static field problems in electrical engineering are considered in this paper. The choice of a suitable BEM formulation for electrostatics, steady current flow fields or magnetostatics is discussed from user's point of view. The dense BEM matrix is compressed with an enhanced fast multipole method (FMM) which combines well-known BEM techniques with the FMM approach. An adaptive grouping scheme for problem oriented meshes is presented along with a discussion on the influence of the mesh to the efficiency of the FMM. The computational costs of the FMM algorithm are analyzed for typical problems in practice. Finally, some electrostatic and magnetostatic numerical examples demonstrate the simple usability and the efficiency of the FMM. 1 Introduction By today, numerical field simulations have become accepted tools in science and industry. Engineers demand fast and accurate numerical solutions along with an easy handling of the software tool. Of course, these points are mainly influenced by the implementation of a numerical method and its user interface. But the underlying numerical method is very important, too. That's why boundary element methods are very attractive for practical applications. Only the surfaces of the considered bodies must be modeled and discretized, since the surrounding air is implicitly taken into account. This fact makes the pre-processing clear and simple. Experienced users can easily control the mesh quality as well as accuracy and processing time. Users of numerical simulation Dedicated to George C. Hsiao on the occasion of his 70th birthday.
Verschleißfreie magnetische Getriebe : Übertragung von Kräften über magnetische Felder
A new approach to the 2D-TE inverse electromagnetic mediumscattering problem
Meshfree Computation of Field Lines Across Multiple Domains Using Fast Boundary Element Methods
Ieee Transactions on Magnetics, Mar 1, 2015
ABSTRACT A meshfree postprocessing for the computation of field lines suggests itself in the case... more ABSTRACT A meshfree postprocessing for the computation of field lines suggests itself in the case of fast boundary element methods. Field values are only calculated and stored in points, which are absolutely necessary for field line computations. Hence, the total amount of processed data is dramatically reduced in comparison to a mesh-based approach along with precomputed field values in all mesh nodes. An automatic and robust domain detection method enables reliable identifications of intersections of field lines with domain boundaries even in the case of complex-shaped surfaces. A combination of automatic domain detection and adaptive step size control of the underlying Runge–Kutta–Fehlberg method results in correctly and efficiently computed field lines, including sharp bends at domain boundaries.
Accurate and Efficient Calculation of the Inductance of an Arbitrary-Shaped Coil Using Surface Current Model
Ieee Transactions on Magnetics, Mar 1, 2015
Meshfree Computation of Field Lines Across Multiple Domains Using Fast Boundary Element Methods
IEEE Transactions on Magnetics, 2015
ABSTRACT A meshfree postprocessing for the computation of field lines suggests itself in the case... more ABSTRACT A meshfree postprocessing for the computation of field lines suggests itself in the case of fast boundary element methods. Field values are only calculated and stored in points, which are absolutely necessary for field line computations. Hence, the total amount of processed data is dramatically reduced in comparison to a mesh-based approach along with precomputed field values in all mesh nodes. An automatic and robust domain detection method enables reliable identifications of intersections of field lines with domain boundaries even in the case of complex-shaped surfaces. A combination of automatic domain detection and adaptive step size control of the underlying Runge–Kutta–Fehlberg method results in correctly and efficiently computed field lines, including sharp bends at domain boundaries.
An Accurate and Efficient Hybrid Method for the Calculation of the Equivalent Capacitance of an Arbitrary Shaped Coil
IEEE Transactions on Magnetics, 2015
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Papers by Wolfgang Rucker