ResearchActivities

Noise monitoring and mitigation

Abstract:
This research addresses the issue of squealing noise, a major negative effects of urban rail transport. The study examines the causes, manifestations, and potential mitigation techniques for noise generated by the instability of friction forces at the wheel-rail interface.

Main objectives:

  • To clarify the mechanisms behind the occurrence of squealing and flanging noise generated between the wheel and the rail.

  • To develop devices for autonomous monitoring and analysis of noise in rail transport.

  • To explore and develop active noise reduction methods by modifying the friction conditions at the wheel-rail interface.

Research content:
Excessive noise and vibrations are major negative impacts of urban rail transport, typically manifesting as squeaking or squealing noises when a rail vehicle navigates curves. This type of noise originates at the railhead due to lateral wheel slip or in contact with the wheel flange and is primarily influenced by factors such as vehicle speed, weather conditions, and track state. The experimental research focuses on understanding the mechanisms of noise generation. Current findings suggest that the instability of friction forces in the contact area, known as the falling friction characteristic, plays a crucial role and interacts with other dynamic modes.

The impact of weather and operational conditions is analysed through noise monitoring in real tram operations in collaboration with the Brno City Transport Company. For this purpose, a noise monitoring module is being developed, enabling autonomous assessment of noise causes through real-time frequency analysis. Correct identification of the noise source is essential for effective reduction, leading to the development and testing of active methods aimed at modifying the friction conditions in the wheel-rail contact.

Publications:
GALAS, R.; OMASTA, M.; KLAPKA, M.; KAEWUNRUEN, S.; KŘUPKA, I.; HARTL, M. Case study: the influence of oil-based friction modifier quantity on tram braking distance and noise. Tribology in Industry, 2017, vol. 39, no. 2, p. 198-206. ISSN: 0354-8996. https://doi.org/10.24874/ti.2017.39.02.06

NAVRÁTIL, V.; GALAS, R.; KLAPKA, M.; KVARDA, D.; OMASTA, M.; SHI, L.; DING, H.; WANG, W.; KŘUPKA, I.; HARTL, M. Wheel Squeal Noise in Rail Transport: The Effect of Friction Modifier Composition. Tribology in Industry, 2022, vol. 44, no. 3, p. 361-373. ISSN: 0354-8996. https://doi.org/10.24874/ti.1211.11.21.02

Partners and Collaboration:
The Brno Public Transport Company, a.s., Hlinky 64/151, Brno, 603 00, Czech Republic.

TRIBOTEC, spol. s r.o., Košuličova 656/4, 619 00 Brno-jih-Horní Heršpice, Czech Republic.

Projects:
Josef Bozek National Center of Competence for Surface Vehicles, Technology Agency of the Czech Republic (TA CR) – National Centres of Competence 1, TN01000026, 2018-2022.

Squeal noise generation in the wheel-rail contact with modified friction, Czech Science Foundation – Standard grant projects, 20-23482S, 2020-2022.

Development of wayside unit for railway noise mitigation, Technology Agency of the Czech Republic (TA CR) – ZÉTA applied research support programme, TJ01000427, 2018-2019.

Contact person:
Ing. Milan Omasta, Ph.D.