Time-domain modelling of high-frequency wheel/rail interaction
Doktorsavhandling, 2011

The interaction between wheel and rail is the predominant source of noise emission from railway operations in a wide range of conventional speeds. On the one hand, this wheel/rail noise concerns rolling noise and impact noise caused by the vertical interaction excited by roughness and discrete irregularities of the wheel/rail running surfaces, respectively. On the other hand, it concerns squeal noise generated by the tangential interaction due to frictional instability. The aim of this thesis is to develop a model for the combined vertical and tangential wheel/rail interaction induced by roughness, discrete irregularities or frictional instability. This is the main step in the formulation of a combined prediction model for the three different types of wheel/rail noise, which can be used as a design tool for noise reduction. In order to include the non-linearities in the contact zone, the interaction model presented in this thesis is formulated in the time domain. Wheel and track models are represented by Green’s functions, which leads to a computationally efficient formulation and allows the inclusion of detailed contact models. A two-dimensional (2D) vertical contact model consisting of a bedding of independent springs, and a three-dimensional (3D) vertical and tangential model based on an influence-function method for the elastic half-space, are considered. Non-Hertzian and transient effects are taken into account. In the thesis, the vertical interaction model has been applied for excitation by wheel/rail roughness and by wheel flats. In the former case, the model has been validated against existing established models. In the latter case, encouraging agreement with field measurements has been found. Results from simulations carried out with both the 2D and the 3D contact models for excitation by detailed measured roughness data indicate that significant errors may occur in the calculated contact forces, when the 3D roughness distribution is represented by the roughness on only one longitudinal line. The errors increase with a decrease in roughness correlation across the width of the contact. Frictional instabilities during curve negotiation have been investigated with the combined vertical/tangential interaction model. For both a constant friction law and a friction curve falling with the sliding velocity, stick/slip oscillations were observed. While the model is not yet considered completely reliable in the case of a falling friction curve due to the possibility of multiple solutions, the results in the case of constant friction are in good qualitative agreement with previously published findings on curve squeal.

frictional instability

non-Hertzian contact

railway noise

discrete irregularities


time domain

transient contact

wheel/rail interaction

Room VG, Sven Hultins gata 6, Chalmers University of Technology
Opponent: Dr. Luis Baeza González, Polytechnic University of Valencia, Spain


Astrid Pieringer


A fast time-domain model for wheel/rail interaction demonstrated for the case of impact forces caused by wheel flats

7th European Conference on Noise Control 2008, EURONOISE 2008; Paris; France; 29 June 2008 through 4 July 2008,; (2008)p. 2643-2648

Paper i proceeding

A time domain model for the wheel/rail interaction aiming to include non-linear contact stiffness and tangential friction

Proceedings of the 9th International Workshop on Railway Noise (IWRN9),Munich, Germany, 2007 (published on CD),; (2007)

Paper i proceeding

A time-domain model for coupled vertical and tangential wheel/rail interaction - a contribution to the modelling of curve squeal

Notes on Numerical Fluid Mechanics and Multidisciplinary Design,; (2010)p. 221-229

Paper i proceeding


Hållbar utveckling



Building Futures


Annan materialteknik

Strömningsmekanik och akustik



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3204

Room VG, Sven Hultins gata 6, Chalmers University of Technology

Opponent: Dr. Luis Baeza González, Polytechnic University of Valencia, Spain