:Wheel defects, such as pitting, generally occur on the tread of railway vehicle wheels. The measured wheel out-of-roundness (OOR) signals usually contain interference signals induced by pitting or other defects. The dimension of pitting is less than wheel-rail contact patch. The morphology filtering method is used to de-noise the wheel OOR signals. The influence of structure element's dimension and shape of morphology filter on the de-nosing of wheel OOR signals is investigated. A new de-nosing method combining morphology filtering with cubic spline smoothing is proposed to overcome the shortcoming of morphology filter. The results of wheel OOR signals processed using the new and ordinary methods are compared. Moreover, the influence of wheel OOR on wheel-rail dynamic interaction is also investigated by using wheel OOR signals from different de-nosing methods. The results indicate that the morphology filter with triangular structure element, of which the amplitude and width are 1 mm and 4 mm, respectively, combined with cubic spline smoothing is more suitable in the de-nosing of wheel OOR signals. The results of this method applied to process wheel OOR signals show that the signal-noise ratio of the processed signal is much higher than the ordinary method and can keep the main characteristics of the original signal.
:Wheel out-of-roundness(OOR) is a common problem in railway industry, which has a great influence on vehicle running safety and wheelset maintenance. Wheel OOR of type B metro train has been investigated through extensive field measurement on six metro lines. The measurement results indicate that most of wheels on five of six metro lines exhibit eccentricity and the development of wheel OOR is very slow. However, wheels on the other one metro line suffer from serious OOR problems with eccentricity and orders 5-8. The wheels with serious OOR exhibits obvious hollow wear on the wheel tread, and the matching relationship between brake shoe and wheel tread is poor. The repairment function of brake shoe for wheel OOR is lost, which leads to rapid development of wheel OOR. According to field investigation and analysis of test results, three measures are proposed to reduce the development of wheel OOR, including reducing the starting acceleration, improving the matching relationship between brake shoe and wheel tread and reducing the dynamic wheel/rail interaction. Wheel re-profiling threshold value is proposed based on the influence of wheel OOR on vehicle dynamics performance. The recommendation maximum allowable value of the radial run-out of wheels is 0.4 mm for low order OOR.
:In order to study the dynamic response characteristics of wheel/rail system of linear induction motor (LIM) metro vehicle and rotary motor (RM) metro vehicle, the KALKER's linear creep theory is used to the wheelset steering abilities during the two types of vehicle curve negotiation under driving, then the LIM and RM vehicle-track coupling dynamic models are established, which are used to investigate the effect of traction force and curve radius on wheel/rail dynamic interactions of LIM vehicle and RM vehicle.The result shows that the traction force has a negligible effect on the wheel/rail creep and dynamic interaction characteristic for the LIM vehicle, and its wheel/rail creep force is not limited by the wheel/rail creep saturation. LIM metro vehicles are better than traditional RM metro vehicles in terms of the steering ability of guiding wheelset on curve tracks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.