A comparative analysis of ballasted vs. slab track vibrations as a cause of rolling noise

• Type: Article in International Conference Proceedings Book
• Date: 2009

Authors

Vale, C (Author) FEUP; Calcada, R (Author) FEUP

Conference proceedings International

Title: 8th European Conference on Noise Control 2009, EURONOISE 2009 - Proceedings of the Institute of Acoustics

8th European Conference on Noise Control 2009, EURONOISE 2009

Edinburgh, 26 October 2009 through 28 October 2009

Indexing

ISI Web of Knowledge

Scopus - 0 Citations

Other information

Authenticus ID: P-008-5CN

Abstract (EN): Nowadays the high speed of trains is one of the reasons for noise emission and track damage. Railway noise may be of different types: rolling noise, traction or aerodynamic noise, however rolling noise seems to be the most predominant. This type of noise results of structural vibration of the wheel, the rail and the sleepers induced by track and wheel excitation, such as track or wheel roughness in addition to the parametric excitation at the sleeper-passing frequency. The parameters influencing noise generation are: track and wheel roughness; contact patch; wheel and rail isolated defects; trains speeds; sleeper spacing, creepage of wheels on curves, etc. The noise reduction is done in two directions: eliminating the sources of noise or reducing noise level. Priority should be given to measures at the source, vehicles and track, as they generally are more cost-effective. And to fulfil this objective maintenance of vehicles and track may play an important role in noise reduction. The main objective of the research presented in this paper is not the prediction of rolling noise in rail track but the study of a ballasted and a slab track in terms of track vibrations, since they are a cause of rolling noise. Therefore, besides the two types of rail tracks, two quality scenarios are analysed: tracks excited by parametric excitation at the sleeperpassing frequency (perfect track) and random excitation due to track roughness with wavelength between 3 and 25 m. As far as the track roughness is concerned, it is adopted a track profile with standard deviation corresponding to the limit for preventive railway maintenance for train speeds of 220 to 300 km/h. A time domain methodology is adopted to identify track frequency resonances and also to calculate wheel/rail interaction forces and track vibration at the two quality scenarios. The adopted dynamic interaction model is composed by a vehicle model, a non-linear Hertzian contact formulation and a track model. The vehicle model consists of a quarter bogie defined by axle and bogie masses and by primary suspension characterized by its stiffness and damping. The track is modelled as a rail discretely supported by sleepers on a ballast layer or a concrete slab. The foundation consists of distributed springs with no interaction between them. The study reaches the conclusion that the interaction contact force and the track vibration due to parametric excitation is not significant compared with those due to the rough track. It was also found that in slab track the dynamic interaction load is higher than in ballasted track, which may be a reason for the higher level of rolling noise in slab tracks.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10