Abstract
As much as there has been a significant increase in the development of railway systems in recent years, one of the significant drawbacks on this mode of transport is ground-borne vibrations and noise emanating from vehicle-track interaction in service. This greatly affects the ecology and physical surroundings of the railway track. Experimental tests and Finite Element modal and complex eigenvalue analysis are conducted to investigate the dynamics of a traction wheelset and rail track. This is done to establish the correlation between the short pitch rail corrugation in the Belfast to Steelpoort railway line, in the Limpopo Province of South Africa, with railway wheel-tract resonance at low frequencies of excitation. A 3D Finite Element Method (FEM) and complex eigenvalue analysis are used to validate the resonance modes of the wheelset and rail track obtained through experimental modal analysis. Mode shapes are determined for natural frequencies that match the excitation frequency induced by short pitch rail corrugation. The results show that based on average train speeds around track curves, the excitation frequency induced by corrugation matches (quite reasonably) natural frequencies of the wheelset. Whilst the wheelset FEM results are in better agreement, they rather prove the correlation to occur at 100 Hz. In a previous study by the authors, at the average speeds per track curve, the corrugation excitation frequency was found to be 108 Hz. The current study goes further by investigating natural frequencies of rail tracks. Moreover, mode shapes of a traction wheelset and rail tracks are also investigated, and the results are presented herein.
Highlights
Effects of ground-borne vibration and its impact on the railway track and the ecology in the physical surroundings of the track are noted in the railway line in the Limpopo Province of South Africa
Train speeds are downloaded from locomotives, for each track curve affected by rail corrugation
The results are outlined in the following order; calculation of corrugation frequencies, D39 200 traction wheelset experimental modal analysis, FEA modal analysis results for the wheelset, the experimental modal analysis on rail track, and the FEA complex eigenvalue analysis results on rail track
Summary
A short pitch periodic waviness (known as rail corrugation) with wavelengths ranging between 58 and 90 mm exists on the running surface of rail track curves in the track between Belfast and Steelpoort, in the Limpopo Province of South Africa. A P2-resonance is a resonance of an unsprang mass making contact with (and exciting) the track stiffness [1] After it has been fixed on the running surface of the rails, corrugation causes high levels of vibration [7], at a frequency that is a function of the corrugation wavelengths and train speeds [1]. The short pitch rail corrugation as formed in the Belfast to Steelpoort track is attributed to low frequency vibrations [10,20,21,22]. Tghteocchaaplletungreesthtoeimprpolebmleemntat its entiretthye, gpirvaectnictahlastoaluptiroanctmicaayl soonlulytiboentwheilbl uodnglyetbaenedfftehcattivite wifoimuldplbeemteimnteedcoonnsuwmhineeglstoancadpatulsroe othnetrack comppornoebnletms. aTthitissemntairkeetys,igtidveiffin tchualttatoproapcttiicmalissoeluthtieonsowluiltlioonnl,yabseeevffeercytivceomif ipmopnleenmteonfteadwonhewehlseeetls-track systemandhaslsotoobnetrdaackmcpoemdpaonedngtsi.vTehnistimmaekefsorittdrifafliscualnt tdoionpstpimecistieotnhse.solution, as every component of a wheelset-track system has to be damped and given time for trials and inspections
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