Abstract
Asymmetrical rail grinding in sharp-radius curves could reduce the side wear of railheads and enhance curve capacity of rail vehicles. The wheel/rail contact performance and curve capacity could be further improved by the optimization of the asymmetrical rail grinding target profile. In order to modify the target profile smoothly, the nonuniform rational B-spline curve with adjustable weight factors is used to establish a parameterized model of railhead curves in the asymmetrical grinding region. The indices of contact performance and curve capacity for different weight factors are obtained using experiment design and service performance simulation. Two Kriging surrogate models are proposed, in which the design variables are the adjustable weight factors, and the response parameters are the indices of contact performance and curve capacity, respectively. The multi-objective optimization model of the target profile is established, in which the objective functions are the two Kriging surrogate models of contact performance and curve capacity. The optimized weight factors are sought using a nondominated sorting genetic algorithm II, and the corresponding optimal target profile is obtained. The wheel/rail service performance simulation before and after optimization indicates that the contact performance and curve capacity are improved significantly.
Highlights
IntroductionWith the increase in speed and quantity of rail vehicles, rail side wear has become important in sharp-radius curves (for the passenger train operating at speed up to 250 km/h, the sharp curve means that the curvature radius is \4000 m), and rail corrosion has fallen into the category of rail damage.[1]
With the increase in speed and quantity of rail vehicles, rail side wear has become important in sharp-radius curves, and rail corrosion has fallen into the category of rail damage.[1]
This article constructed the parameterized model of the asymmetrical rail grinding target profile in sharp-radius curves based on an nonuniform rational B-spline (NURBS) curve
Summary
With the increase in speed and quantity of rail vehicles, rail side wear has become important in sharp-radius curves (for the passenger train operating at speed up to 250 km/h, the sharp curve means that the curvature radius is \4000 m), and rail corrosion has fallen into the category of rail damage.[1]. For the purpose of obtaining a reasonable rolling radius difference and reducing contact stress, Jia and Si5 designed an optimal grinding target profile in sharp-radius curves based on practical rail grinding experience. This work focuses on the construction of a parameterized model of the asymmetrical rail grinding target profile using the nonuniform rational B-spline (NURBS) curve, taking weight factors of the NURBS curve as the adjusted variables for the railhead curve of the parameterized model. It solved the problem of the target profile not being adjusted continuously and precisely. The precise optimal asymmetrical rail grinding target profile is designed using a multi-objective global optimization method
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