# Category Archives: Mathematics

# ECMI 2018 in Budapest

- Kulchytska-Ruchka, Iryna ; Schöps, Sebastian ; Gander, Martin J. ; Niyonzima, Innocent : Convergence analysis of Parareal for systems with discontinuous inputs.
- Cortes Garcia, Idoia ; De Gersem, Herbert ; Schöps, Sebastian : Generalised elements for the analysis of field/circuit coupled systems.
- Bontinck, Zeger ; Corno, Jacopo ; Schöps, Sebastian ; De Gersem, Herbert : Iso-Geometric Analysis as a Tool for Simulating Electrical Machines.

# Preisverleihung im hessischen Mathematikwettbewerb

In seinem abschließenden Vortrag zeigt Sebastian Schöps Möglichkeiten auf, wie Algorithmen und Berechnungen tatsächlich zum Einsatz kommen. Zum Beispiel könne mit Programmen simuliert werden, welche Schäden für die Gesundheit der Menschen entstehen, wenn sie permanent mit dem Handy am Ohr durch die Welt spazieren – ganz ohne Versuche direkt am Menschen.Tatsächlich simuliert man nicht die Schäden, sondern die Erwärmung (oder noch genauer die Energiedeposition) als “multiphysikalisches Problem”, siehe z.B. die Veröffentlichung aus 2002 von Gjonaj, Bartsch, Clemens, Schupp, Weiland. Simulation oder nicht, es gibt bisher keinen wissenschaftlichen Nachweis über Schäden. Die aktuellen Grenzwerte und viele weitere Informationen zum Thema findet man z.B. beim Informationszentrum Mobilfunk.

Update: Mehr Informationen auf Hessenmetall.de.

# The International Symposium on Electric and Magnetic Fields 2018 is over

# A New Parareal Algorithm for Problems with Discontinuous Sources

# Pressemitteilung zu PASIROM

# New paper on isogeometric analysis of electrical machines

Computer Methods in Applied Mechanics and Engineering has accepted our paper on *Isogeometric analysis and harmonic stator–rotor coupling for simulating electric machines* with DOI 10.1016/j.cma.2018.01.047. The paper proposes Isogeometric Analysis as an alternative to classical finite elements for simulating electric machines. Through the spline-based discretisation it is possible to parametrise the circular arcs exactly, thereby avoiding any geometrical error in the representation of the air gap where a high accuracy is mandatory.

Update: get the paper for free before April 10, 2018 at authors.elsevier.com.

# First results on fast high-order IGABEM

# Talk on the symplectic methods in our seminar from MOX

# New paper on Waveform Relaxation for Multiscale Problems

This paper proposes the application of the waveform relaxation method to the homogenization of multiscale magnetoquasistatic problems. In the monolithic heterogeneous multiscale method, the nonlinear macroscale problem is solved using the Newton–Raphson scheme. The resolution of many mesoscale problems per Gauss point allows to compute the homogenized constitutive law and its derivative by finite differences. In the proposed approach, the macroscale problem and the mesoscale problems are weakly coupled and solved separately using the finite element method on time intervals for several waveform relaxation iterations. The exchange of information between both problems is still carried out using the heterogeneous multiscale method. However, the partial derivatives can now be evaluated exactly by solving only one mesoscale problem per Gauss point. Continue reading →