In view of the coexistence of wheel profile wear (WPW) and wheel diameter difference (WDD) on an actual subway line, a dynamic analysis method based on coupling between WPW and equivalent in-phase WDD was proposed. Based on the measurements from a subway vehicle in operation on this line, dynamics modeling and calculations were performed for a single carriage of this vehicle. Later, the interaction between the effects of WPW and equivalent in-phase WDD on the vehicle dynamic performance was analyzed, and the dynamic response in the presence of coupled damage was compared between the outer and inner wheels. Furthermore, the difference in the dynamic response caused by different positions of the larger-diameter wheels (i.e., on the inner track or outer track) was analyzed for the case where equivalent in-phase WDD occurred between the front and rear bogies. The results show that when the vehicle ran on a straight line, the coupling between WPW and WDD reduced the vehicle’s stability but improved its ride comfort. When the vehicle traveled on a curved line, it showed reductions in the lateral wheel/rail contact force, derailment coefficient, axle lateral force, and wear index if the outer wheels had a larger diameter. As a result, the deterioration of the vehicle’s dynamic performance due to the increasing degree of WPW slowed down, and its curve negotiation performance improved. Meanwhile, the outer wheels had significantly greater lateral wheel/rail contact force, derailment coefficient, and wear index compared to the inner wheels. When a −1 mm WDD was coupled with the worn wheel profile for 14 × 104 kilometers traveled, the dynamic performance indexes of the vehicle were close to or even exceeded the corresponding safety limits. The findings can provide technical support for subway vehicle maintenance.
Purpose
The purpose of this study is to match appropriate friction coefficients for subway operational vehicles, considering the dynamic variations of wheel profile wear.
Design/methodology/approach
This study combines experimental testing and numerical simulation to investigate the influence of wheel profile wear coupled with the friction coefficient on the vehicle dynamic response.
Findings
For the test route in this paper, it is recommended to control the friction coefficient on straight sections between 0.25 and 0.3, and on curved sections between 0.2 and 0.3. This satisfies the required adhesion coefficient for normal train traction and braking, while also ensuring the straight running performance and curve negotiation performance of the vehicle.
Practical implications
Reasonable friction coefficient ranges are proposed for straight and curved track lines to improve the operational safety and economy of the vehicles. Moreover, this study can provide a theoretical basis and reference direction for developing anti-wear measures for rail vehicles operating on fixed routes.
Originality/value
Considering the wear characteristics of operating vehicles and the dynamic changes in the wear profile, this paper explores the adaptability of different degrees of wheel wear profiles to different friction coefficients. Based on the response characteristics of vehicle dynamics, reasonable lubrication recommendations are proposed for this operating vehicle.
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