# Category Archives: Mathematics

# 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 →

# How to build GNU Octave with Qt5 on the Mac

The graphical user interface of Octave 4.0 can only be compiled with Qt4. Homebrew is dropping 4.x support and moving towards 5.x. Several Octave dependencies have already been updated (e.g. Qscintilla2, see e.g. this issue. However, the upcoming Octave 4.2 (release is scheduled for September 2016) will have full Qt5 as discussed here.

The standard installation uses the command line interface. If you need Octave with graphical user interface then this should workbrew update brew upgrade #to get the latest qscintilla brew install octave --with-gui --HEAD

**Update**: The post has been edited on Aug 20 since the new formula is now available in homebrew’s science repository.

# Jan ter Maten visits TU Darmstadt

# Three presentation from CE@TUDa at ECMI 2016

- Recent developments and applications of isogeometric methods
- Mathematical modeling and simulation for nanoelectronic coupled problems (nanoCOPS)
- Stochastic PDEs and uncertainty quantification with applications in engineering

# Invited Talk by Sergej Rjasanow on FEM on polyhedral meshes

In the development of numerical methods to solve boundary value problems the requirement of flexible mesh handling gains more and more importance. The BEM-based finite element method [1] is one of the new promising strategies which yield conforming approximations on polygonal and polyhedral meshes, respectively. Continue reading →

# Darmstadt is well prepared for the future…

*Hier profitiert Darmstadt von seiner 1877 gegründeten Technischen Universität. Hinzu kommt die Sogwirkung auf High Potentials durch drei Fraunhofer-Institute und das GSI Helmholtzzentrum für Schwerionenforschung, das gerade den Bau eines gigantischen Teilchenbeschleunigers vorbereitet.*”