Publications in Scientific Journals:

C. Rößler, I. Hafner, B. Heinzl:
"Discussion of two Case Studies on DAEs using Different Approaches for Regularisation";
Simulation Notes Europe, 24 (2014), 3-4; 179 - 184.

English abstract:
Abstract. The object-oriented model description of
physical or mechanical systems leads to differentialalgebraic
equations. In general the numerical solution of
such equation systems is very complex, numerically
extensive or may even be impossible. Therefore it is
important to find methods for solving given equation
system, this leads to the so-called index reduction and
regularization methods. This paper gives a short overview
of common methods of index reduction. Additionally
a classification of these different approaches is made.
Afterwards each approach is presented in detail and the
advantages and disadvantages of the different methods
are discussed. In order to compare the different index
reduction methods, the methods described above are
demonstrated by various examples. For the comparability
of the different methods the obtained numerical
solutions and the deviation from the constraint equations
are displayed graphically. Therefore the distinct
approaches can be compared with regard to their numerical
solutions. The two examples are mechanical
systems with differential index three. The equations of
motion of a pendulum on a circular path in Cartesian
coordinates and the motion of the double pendulum in
Cartesian coordinates, which shows a chaotic behaviour,
are used as case studies.

"Official" electronic version of the publication (accessed through its Digital Object Identifier - DOI)

Electronic version of the publication:

Created from the Publication Database of the Vienna University of Technology.