Curve squeal is a highly disturbing tonal sound generated by rail vehicles when negotiating a sharp curve. It is attributed to self-excited vibrations caused by stick/slip behaviour due to lateral creepage of the wheel tyre on the top of the rail. Regarding the large number of rolling stock units and the long lifetime of waggons there is an urgent need for a cheap and simple retrofitting measure to reduce curve squeal. The main objective of the project is therefore to investigate the potential to reduce curve squeal by means of active control especially in the form of dither in an efficient and robust way. Dither control is an open loop control. It consists in adding a forced vibration to the vibrational system. The demand on this additional signal is that it is higher in frequency than the friction-induced response. From a physical point of view, dither control modifies the effective friction characteristic. In the project, dither control is evaluated and optimized with respect to signal contents by means of an advanced model for curve squeal. Findings from the theoretical analysis will be experimentally evaluated in a test rig.
Professor vid Chalmers, Architecture and Civil Engineering, Applied Acoustics
Forskare vid Chalmers, Architecture and Civil Engineering, Applied Acoustics
Funding years 2015–2017
Areas of Advance