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The efficiency of tram articulations compared to vibroacoustic emissions

Nowakowski T., Komorski P., Tomaszewski F.

Archives of Transport

2017

Vol. 44, iss. 4

55--63

Human quality of life is constantly increasing, and so does the comfort of travel by various means of public transport, especially rail transport. One of the more crucial criteria for assessment of travel comfort is vibroacoustic comfort. This aspect is also substantial among rail vehicle operators and manufacturers. Sound quality evaluation is related to psychoacoustic indicators, but reducing the levels of acoustic pressure does not always correlate to increased quality of the perceived sound and improvement of human sound perception. Moreover the cause of unpleasant noise has to be taken into consideration. In many examples it is induced by specific vibrations and/or friction forces through components. The following article presents experimental research carried out in the in-situ conditions, testing the quality of work carried out by tram articulations considering vibroacoustic emissions. Several measurements were taken of vibroacoustic signals in several urban rail vehicles of the same type. Two different trams were chosen for analysis and their vibroacoustic emission levels as well as sound quality parameters were compared. One of the more crucial aspects of the research was to determine the dependency between vibrations around the area of articulations and squealing noise. The results indicate a large correlation between signals and deterioration in the work quality of the articulation in the given tram. Moreover, the authors suggest expanding on currently carried out maintenance in order to minimise inconvenient vibroacoustic phenomena during use.

Parametryzacja i ocena hałasu pisków od krzywizn i hamowania podczas dojazdu pociągu do stacji

Wszołek T., Koter M.

Przegląd Mechaniczny

2015

nr 7-8

38--42

Dominującym źródłem hałasu kolejowego w przeważającym zakresie prędkości jest hałas toczenia wywołany drganiami kół i szyn spowodowanymi drganiami powstającymi na styku koło/szyna. Hałas toczenia ma charakter szerokopasmowy o narastającym udziale wyższych częstotliwości wraz ze wzrostem prędkości pociągów. Ale piski na krzywiznach są jednymi z najgłośniejszych i najbardziej dokuczliwych źródeł hałasu od linii kolejowych metra i tramwajów. Są one również spowodowane interakcją pomiędzy kotem a szyną, ale mają zupełnie inny charakter Są silnie tonalne i występują w ostrych łukach, a powodowane są drganiami kota w jednym z jego rezonansów. Można tu rozróżnić piski spowodowane ocieraniem bocznej i górnej części szyny, jak również piski od ocierania kołnierza. Podobnym zjawiskiem jest pisk hamulców, który jest emitowany w czasie hamowania.

The most important source of noise from railways at most speeds is a rolling noise caused by wheel and rail vibrations induced at the wheel/rail contact. The rolling noise is fairly broad-band in nature, the relative importance of higher frequency components increasing as the train speed increases. But the curve squeal is one of the loudest and most disturbing noise sources from railways metros and tramways. It is also caused by interaction between wheel and rail but bas a quite different character. It is a strongly tonal noise occurring in sharp curves, being associated with vibration of the wheel in one of its resonances. It is also necessary to distinguish between the squeal caused by lateral creepage, top of rail squeal as well as flange squeal. A similar phenomenon is a brake squeal which is emitted during braking.