SAMBA 2 – Wear on wheels and rails

Background

The aim of the closely related projects SAMBA 2 and SAMBA 6 is to improve the knowledge of how wheel and rail profiles change over time due to wear and plastic deformation. Different vehicle designs, track geometries and operational conditions are considered. As a result actions on how to reduce wheel-rail wear and profile changes may be proposed.

Project Description

Phase I, 1996–1998

During the first period of the project comprehensive measurements of wheel/rail profiles and hardness were performed on the Stockholm commuter service. Measured vehicles were classes X1 and X10. Rail measurements were carried out in the Älvsjö area. The measurement data was evaluated in terms of profile change, wear rate, and profile metrics versus time and mileage or traffic load respectively. A valuable set of reference data for model development to come has thus been created.

Phase II, 1999–2000

This phase was mainly devoted to the establishment of a procedure for prediction of wheel wear including profile evolution with mileage. The general approach was vehicle dynamics simulation using multi-body models (MBS) to assess the contact conditions used as input to a wear model. Several wheel-rail contact models and wear theories were evaluated. A numerical procedure was developed based on a MATLAB structure for iteration control and wear calculation combined with GENSYS for MBS simulations. To obtain sufficient numerical efficiency traditional wheel-rail contact models according to Hertz’ theory and Kalker’s simplified theory were used. The material loss calculation, based on Archard’s model, was developed in the SAMBA 6 project. Validation was performed using the X10 vehicle measurements as reference.

Phase III, 2001–2003

During this phase the concept of vehicle dynamics simulations for prediction of wheel and rail wear was further developed and published internationally. Simulations with tractive forces were introduced in order to represent realistic wear contributions from disc or electric braking. Operational conditions for non-dry contact conditions were studied to improve the potential for full-scale wear simulations. The wear calculations were refined and the contact model improved by considering the surface elasticity in determining the relative sliding velocity.

As a further application an extended Master project was launched in cooperation with Bombardier Transportation. The objective was to simulate the wear development of X2000 trailing wheels on the line Stockholm-Göteborg and compare with existing measurements. The agreement turned out to be fairly good.

Phase IV, 2004–2006

This project phase has seen advances in the areas validation, model comparison, and rail wear simulation.

The validation of the improved wheel wear prediction procedure was concluded by a full set of simulations of the X10 service. Beneficial effects of the model improvements were shown and good agreement with the measurements was obtained.

On wheel-rail interface level improved understanding has been reached regarding contact and wear models. Non-elliptic contact models with and without half-space assumption have been compared to a traditional model. Furthermore, comparisons were carried out between friction work based wear models and the currently used Archard implementation.

Finally a procedure for simulations of rail wear has been developed. Much of the methodology from the wheel wear simulations could be used. The set of vehicles travelling the track in question needs to be defined in order to predict the successive rail wear. As reference the measured rail profile evolution in the Älvsjö area was used. As a further application a Master project was carried out, simulating rail wear on Tvärbanan in Stockholm. Reference measurements were performed by SL.

Participants

Mats Berg, Professor
Tomas Jendel, Lic. Tech., phase I - II.
Rickard Nilsson, Dr. Tech., phase I - II.
Roger Enblom, Dr. Tech., phase III - IV.

Publications

•  Enblom R: Deterioration mechanisms in the wheel-rail interface with focus on wear prediction – A literature review, Vehicle System Dynamics, Vol. 47, No. 6, pp. 661-700, 2009.
• Enblom R and Berg M: Impact of non-elliptic contact modelling in wheel wear simulation, Wear 265, pp. 1532-1541, 2008.
• Enblom R and Berg M: Proposed procedure and trial simulation of rail profile evolution due to uniform wear, Journal of Rail and Rapid Transit, Vol. 222, pp. 15-25, March 2008. (Best paper award for 2008).
• Enblom R: On simulation of uniform wear and profile evolution in the wheel-rail contact, Doctoral thesis, TRITA AVE 2006:83, ISBN 978-91-7178-605-3, KTH, Stockholm, 2006.
• Enblom R and Berg M: Impact of non-elliptic contact modelling in wheel wear simulation, Proceedings of the 7th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Brisbane, Australia, June 24-27, 2006.
• Orvnäs A: Simulation of rail wear on the Swedish light rail line Tvärbanan, Master of Science Thesis, TRITA AVE 2005:12, KTH, Stockholm, 2005.
• Enblom R and Berg M: Emerging engineering models for wheel/rail wear simulation, Proceedings of the 8th International Conference on Railway Engineering, London, June 29-30, 2005.
• Enblom R and Berg M: Simulation of railway wheel profile development due to wear-influence of disk braking and contact environment, Wear 258, pp. 1055-1063, 2005.
• Enblom R and Berg M: Wheel wear modelling including disc braking and contact environment – Simulation of 18 months of commuter service in Stockholm. Proceedings of the 14th International Wheelset Congress, Orlando, October 17-22, 2004.
• Enblom R and Berg M: Towards calibrated wheel wear simulation – A comparison between traditional approach and novel methods. Proceedings of the 6th International Conference on Railway Bogies and Running Gears, Budapest, September 13-16, 2004.
• Enblom R: Simulation of wheel and rail profile evolution – Wear modelling and validation, Licentiate thesis, TRITA AVE 2004:19, ISBN 91-7283-806-X, KTH, Stockholm, 2004.
• Enblom R and Berg M: Simulation of wheel profile development due to wear – influence of disk braking and contact environment. Proceedings of the 6th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Gothenburg, Sweden, June 10-13, 2003.
• Enblom R: Prediction of wheel and rail wear – A literature survey, Report, TRITA AVE 2003:27, KTH, Stockholm, 2003.
• Dirks B: Vehicle dynamics simulation of wheel wear for Swedish high-speed train X2000, Master of Science Thesis, TRITA AVE 2003:16, KTH, Stockholm, 2003.
• Nilsson R: Rail wear development - measurements and evaluation, Report, TRITA FKT 2002:22, KTH, Stockholm 2002.
• Jendel T and Berg M: Vehicle dynamics simulations of wheel wear, Proceedings of the 5th International Conference on Railway Bogies and Running Gears, Budapest, September 24-26, 2001.
• Jendel T and Berg M: Prediction of wheel profile wear – methodology and verification, Vehicle System Dynamics, Supplement 37, pp. 502-513, 2002.
• Jendel T and Berg M: Prediction of wheel wear for rail vehicles – methodology and verification, Proceedings of 3rd Contact Mechanics Int. Symp., Peniche, Portugal, June 17-21, 2001.
• Jendel T: Prediction of wheel profile wear – methodology and verification, Licentiate thesis, TRITA FKT 2000:49, KTH, Stockholm, 2000.
• Jendel T: Prediction of wheel profile wear – comparisons with field measurements, Proceedings of the 5th International Conference on Contact Mechanics and Wear of Rail/Wheel Systems, Tokyo, July 25-27, 2000.
• Nilsson R: Wheel and rail wear – measured profile and hardness changes during 2.5 years for Stockholm commuter traffic, International Conference on Railway Engineering, London, 5-6 July, 2000.
• Nilsson R and Jendel T: Wheel and rail wear – consecutive wheel and rail profile and hardness measurements and verification of a wheel profile predictive tool, EUROMECH Colloquium 409, Hannover, March 6-9, 2000.
• Jendel T: Prediction of wheel and rail wear – a pilot study, Report, TRITA FKT 1999:03, KTH, Stockholm, 1999.
• Olofsson U and Nilsson R: Initial wear of a commuter train track, Nordtrib '98, June 8-10, Ebeltoft, Denmark, 1998.