## Teoretiske og eksperimentelle dynamiske undersøgelser af jernbanekøretøjer

### Jens Christian Jensen

## Summary

The present thesis is concerned with the dynamics of railway vehicles. In
the thesis the dynamics of a mathematical model of the Danish IC3 train is
treated. The mathematical model consists of half a carbody, one bogie and
two wheelsets. The creepage- creepforce relation is approximated by the
theory of Shen, Hedrick and Elkins. The derivation of the dynamical equations
is described, and special focus is placed on the contact between wheel and
rail. This contact is treated locally elastic which means that the wheel is
allowed to penetrate the rail. This method is capable of taking into account
multiple coexisting contact areas between the wheel and rail.
Various examples of the geometrical contact between wheel and rail are given
and the influence of track gauge and rail inclination on the contact is
outlined. The contact-geometry for a worn wheel-profile on new rails is
determined and used in the simulations of the dynamics of the IC3 train.

In the thesis the dynamics are numerically investigated for the IC3 running
on three different track configurations:

- A perfectly straight track
- A measured track with irregularities
- A curve

When running on a straight track, we follow the linear and nonlinear critical
velocities in dependence of the coefficient of adhesion, the longitudinal
stiffness of the primary suspension and the damping coefficient of the
secondary yaw-damper. By the term "nonlinear critical velocity" is meant the
lowest velocity where a stable oscillating solution vanishes in a saddle-node
bifurcation. The critical velocities are computed for the track-gauges 1432 mm
and 1435 mm and the rail-inclinations 1/20 and 1/40. The difference between
linear and nonlinear analysis is discussed in detail. It is shown that the
difference is quite substantial. The numerical calculations indicate that the
track-gauge and rail-inclination has a great influence on the dynamics of the
IC3 train. The computer simulations of the IC3 running on a measured track
with irregularities are compared with the measured signals obtained during a
test-run.
The physical conditions when negotiating a curve are discussed.
Finally a sum up of the experimental experiences obtained during test-runs
are presented. A comparison and discussion of the test and computer results
are given.

## IMM Ph.D Thesis 9, 1995

Last modified August 18, 1996

Finn Kuno Christensen
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