Prediction of Wheel/Rail Profile Wear

SUMMARY

The alteration in wheel and rail profiles due to wear involves considerable vehicle and track-maintenance costs, and influences the loading capacity of the rails, as well as the operation safety and riding comfort of the vehicles. In the past twenty years a vehicle dynamics, contact mechanics and tribology based research work has emerged which is also recently continuous in an international scale, and this research is more and more intensive. Parallel to the growing possibilities of computer based analyses, several algorithms and numerical procedures have been elaborated, as well as measurement based experiments have been carried out to establish the reliable prediction of wear-caused wheel and rail profile alterations and to maximise the mileage performance by selecting the optimum vehicle system parameters for running gears operating on a selected railway line or a whole network under specified -in general inherently stochastic - traffic conditions. This paper takes an attempt to introduce the extended sphere of problems of wheel and rail wear prediction, as well as the latest results reflecting the present state of the art.     

Prediction of Wheel/Rail Profile Wear

The alteration in wheel and rail profiles due to wear involves considerable vehicle and track-maintenance costs, and influences the loading capacity of the rails, as well as the operation safety and riding comfort of the vehicles. In the past twenty years a vehicle dynamics, contact mechanics and tribology based research work has emerged which is also recently continuous in an international scale, and this research is more and more intensive. Parallel to the growing possibilities of computer based analyses, several algorithms and numerical procedures have been elaborated, as well as measurement based experiments have been carried out to establish the reliable prediction of wear-caused wheel and rail profile alterations and to maximise the mileage performance by selecting the optimum vehicle system parameters for running gears operating on a selected railway line or a whole network under specified -in general inherently stochastic - traffic conditions. This paper takes an attempt to introduce the extended sphere of problems of wheel and rail wear prediction, as well as the latest results reflecting the present state of the art.     

Train-Track Interaction and Mechanisms of Irregular Wear on Wheel and Rail Surfaces

Summary High-frequency train-track interaction and mechanisms of wheel/rail wear that is non-uniform in magnitude around/along the running surface are surveyed. Causes, consequences and suggested remedies to relieve the problems are discussed for three types of irregular wheel/rail wear: (1) short-pitch rail corrugation on tangent tracks and large radius curves, (2) wheel corrugation as caused by tread braking, and (3) wheel polygonalisation. The state-of-the-art in modelling of dynamic train-track interaction in conjunction with prediction of irregular wear is reviewed.     

Train-Track Interaction and Mechanisms of Irregular Wear on Wheel and Rail Surfaces

Summary High-frequency train-track interaction and mechanisms of wheel/rail wear that is non-uniform in magnitude around/along the running surface are surveyed. Causes, consequences and suggested remedies to relieve the problems are discussed for three types of irregular wheel/rail wear: (1) short-pitch rail corrugation on tangent tracks and large radius curves, (2) wheel corrugation as caused by tread braking, and (3) wheel polygonalisation. The state-of-the-art in modelling of dynamic train-track interaction in conjunction with prediction of irregular wear is reviewed.     

降低61000发动机气缸磨损的措施和效果

为提高6100发动机缸孔的耐磨性，采用了镶入优质干式缸套的办法，改进了第一首活塞环镀铬层的表面结构，缸孔内表面也由普通珩磨改为平台珩磨，从而使缸孔的磨损有了大幅度降低。     

About Multi-Hertzian-Contact Hypothesis and Equivalent Conicity in the Case of S1002 and UIC60 Analytical Wheel/Rail Profiles

In a previous paper [1], a new method using 'multi-Hertzian' elasticity for identifying equivalent parameters of railway wheelsets rolling on defined tracks was presented. Another method also using Hertzian elasticity [2] has produced different results. Without knowing the origin of these discrepancies, the question was asked whether any of these methods could adequately describe actual non-Hertzian contacts. This paper, using as a basis Kalker's 'Contact' software which solves the non-Hertzian case for normal and tangential forces, answers this question, demonstrating that the assumption of summing Hertzian contacts is realistic provided that enough ellipses are considered. On this basis, the 'equivalent conicity' of the standard wheelset equipped with S1002 profiles rolling on UIC60 (1/40) rails is analysed in the range of small lateral displacements: around 2 mm it amounts to between 0.13 and 0.16. It is demonstrated that, due to actual wheel and rail elasticity, linearization of rigid profiles conicity, whatever method being used, is not realistic in practice.     

The Stationary Motion of a One-Axle Vehicle Along a Circular Curve with Real Rail and Wheel Profiles

In this paper, we present a theory on the stationary motion of a one-axle railway vehicle along a circular curve in the presence of single- or double-point contact. The rail and the wheel profiles may be either stylized or real and as an example we take the profile combination UIC60 1:40 S1002. The mathematical model of the system is based on De Pater's first-order theory [1]. The geometrical contact problem between wheel and rail is solved by using a modified Newton-Raphson procedure. Both the cases with and without friction are considered. When friction is present, the non-linear Kalker creep law [6, 7] is used to describe the physical contact. For various values of the friction coefficient, the cant angle and the curvature of the track, the contact forces are presented as functions of the velocity parameter C v = V 2 / V 2 eq , where V is the velocity of the vehicle and V eq is the equilibrium velocity of the frictionless case. For the case of stylized profiles in which both the wheel treads and the wheel flanges are conical, and the rail cross sections are circular, we have determined the velocity range with single point contact in dependence on the friction coefficient, the conicity of the tread, the curvature of the track and the cant angle.     

The Available Methods to Calculate the Wheel/Rail Forces in Non Hertzian Contact Patches and Rail Damaging

Abstract

In the present paper, the methods used in railway dynamics to take into account the non Hertzian multi contact patches occurring on a wheel, are summarised. Some application cases are presented as well as an explanation of the so called “squat” rail deterioration.     

The Available Methods to Calculate the Wheel/Rail Forces in Non Hertzian Contact Patches and Rail Damaging

In the present paper, the methods used in railway dynamics to take into account the non Hertzian multi contact patches occurring on a wheel, are summarised. Some application cases are presented as well as an explanation of the so called “squat” rail deterioration.     

车轮设计优化及双轴试验

车轮在不同路况下行驶时会同时受到来自各个方向的载荷,因传统的弯曲和径向疲劳试验结果,每次仅模拟车轮单一方面的承载情况,所以若不加以修正,很难代表车轮真实的服役情形。文章在介绍车轮装配的基础上,分析了车辆直线行驶和转弯2种状态下车轮的混合应力谱,并对能同时给车轮施以侧向和径向组合载荷的双轴试验原理、设备、过程及其结果评定作了详细论述。表明LBF开发的双轴疲劳试验机能用简单的程序模拟测试整个车轮的承载情形,来自实际工况的经验、数字评估与试验验证的整合构成了车轮的设计优化。     

Solution of the Multiple Wheel and Rail Contact Dynamic Problem

SUMMARY

An unconventional method for calculating the forces developing in the wheel and rail contact patches of a railway vehicle has been implemented at the New Technology Laboratory of INRETS. It takes into account the elastic deformations of the materials in the Hertzian elliptical contact areas; the possibility of having simultaneously several contact patches on each wheel, is introduced in the simulation of the dynamic phenomena.

The theory is applied for a high speed bogie running on a perfectly straight track.     

Solution of the Multiple Wheel and Rail Contact Dynamic Problem

An unconventional method for calculating the forces developing in the wheel and rail contact patches of a railway vehicle has been implemented at the New Technology Laboratory of INRETS. It takes into account the elastic deformations of the materials in the Hertzian elliptical contact areas; the possibility of having simultaneously several contact patches on each wheel, is introduced in the simulation of the dynamic phenomena.

The theory is applied for a high speed bogie running on a perfectly straight track.     

UGNX高级仿真在摩托车车轮设计中的应用

将摩托车车轮作为研究对象,运用UGNX高级仿真进行5种状态的受力分析,可为摩托车车轮的设计优化提供可靠依据。通过UGNX高级仿真的应用,从而提高摩托车车轮的综合性能水平,改进设计工艺,并直接应用于生产实际,从而大大提高产品的竞争力;无论是结构设计还是强度研究,运用UGNX高级仿真功能进行有限元分析都具有重要意义。