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FUNDAMENTALS OF RAIL VEHICLE DYNAMICS PDF

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namics is fundamental to the control of rail - wheel wear and vehicle stability Although the subject of railway vehicle dynamics is constantly gaining importance. Fundamentals of Rail Vehicle Dynamics - Free ebook download as PDF File .pdf ), Text File .txt) or read book online for free. Fundamentals of Rail Vehicle. A. H. Wickens Fundamentals of rail vehicle dynamics guidance and stability .pdf - Ebook download as PDF File .pdf), Text File .txt) or read book online.


Fundamentals Of Rail Vehicle Dynamics Pdf

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Railway vehicle dynamics Part I: Wheel-rail contact in railway dynamics. ➢ Contact Fundamental for the flange contact point (angle > 1 rad): see latter on θ. PDF | In this paper, the state of the art of railway vehicle dynamics is Download full-text PDF. Sharma of the fundamental aspects of wheel/rail interaction is. Article (PDF Available) in Vehicle System Dynamics 47(11) · October . subsystem and the track subsystem are coupled through a wheel–rail spatial.

Advances in engineering Lisse, Netherlands ;6 TF W53 No part of this publication or the information contained herein may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, by photocopying, recording or otherwise, without written prior permission from the publishers.

Basic Concepts Equations of Motion Dynamics of the Wheelset Guidance of the Two-Axle Vehicle Dynamic Stability of the Two-Axle Vehicle The Bogie Vehicle The Three-Axle Vehicle Articulated Vehicles Unsymmetric Vehicles If reference is made to a section within the chapter containing the section, the section number is cited as a single number.

Otherwise, a section is identified by two numbers separated by a decimal point, the first number referring to the chapter in which the section appears, and the second identifying the section within the chapter. Equations are numbered serially within each section. If reference is made to an equation within the section containing the equation, the equation number is cited as a single number.

If reference is made elsewhere in the same chapter then the equation number is cited as a two-figure number and if reference is made in another chapter all three numbers-chapter, section and equation are cited.

Figures and tables are numbered by chapter. Preface The fundamental method of guidance of the railway vehicle is the coned and flanged wheelset. Whilst facilitating guidance in curves, coning can give rise to sustained lateral oscillations, termed hunting. This oscillation induces forces which can cause damage to both vehicle and track and there can be, at least, discomfort to the passenger and, at worst, the risk of derailment.

Fundamentals of Rail Vehicle Dynamics (Advances in by Alan Wickens PDF

Inadequate steering on curves can have similar consequences. This book concentrates on the resulting problem of the conflict between guidance and stability and its resolution by proper design of the suspension connecting the wheels and car body of the railway vehicle. The invention of the wheelset, the progressive development of the bogie and the various schemes of articulation which have been developed over the years in order to resolve the design conflict between stability and steering, all predate the theory of railway vehicle dynamics.

Engineering insight brought railway technology a long way but empirical methods were not adequate once the railway renaissance started and train speeds increased.

A fundamental change in railway technology took place in which the empirical evolution of railway bogies was replaced by a more scientific and numerate approach. The detailed modelling of the dynamics of railway vehicles is made possible by the several excellent computer packages that are available, which provide sufficiently detailed and validated mathematical models that can be used with confidence in engineering design and development.

These models permit the simulation of the actual motion on a specified stretch of track so that the performance of a specific design can be analysed, or a particular incident recreated.

Thus, by simulation the overall performance of a vehicle can be checked. Realism is, of course, essential in design but equates to complexity, and computer output must be tempered with understanding and scepticism. It is important, therefore, that fundamental principles are well understood.

Fundamentals of Rail Vehicle Dynamics

This book is concerned with the fundamental principles of guidance and stability, which are a consequence of the mechanics of wheel-rail interaction as embodied in the equations of motion. For research purposes, where the objective is to achieve an understanding of an innovative system or a particular problem, simple models can be very useful and can provide productive insights.

Analytical studies which describe the mechanics of various phenomena by the simplest model possible can be used to explore new suspension and vehicle design concepts. PREFACE xii Attention will be concentrated on the configuration and parametric design of the bogie, in relation to steering, dynamic response and stability.

Therefore the treatment of the various configurations of vehicle do not simply concentrate on a current typical set of parameters but attempt to consider the consequences of the complete range of parameters open to the designer.

By this approach, it is possible to see why much of current practice, though it pre-dates the availability of theory, is the way it is. Moreover, it becomes clear why many innovations failed in the past. Because an important consequence of a more analytical approach is to separate out the dynamic properties of a system from the detailed design of its components the latter will not be discussed.

Moreover, the application of active controls to steering and ride control including body tilting will not be covered. Active systems will play a large part in the future and those working in the field will require a sound grounding in passive systems. This makes it possible to consider that, in general, wheelsets and track except in the areas of contact are rigid and that car bodies are without flexibility. This means that some significant phenomena are not discussed here.

Moreover, simple forms of suspension elements are assumed. The more straightforward problems of response in the vertical plane, or in the longitudinal direction are not addressed. The basic concepts are described in Chapter 1. In this Chapter, though an engineering approach has been followed, great reliance has been placed on the careful derivations of Professor de Pater. The following Chapters deal with the single wheelset and then with progressively more complex configurations of vehicle.

Some related areas, such as aerodynamics or crashworthiness, are not covered as they tend to use different techniques and tools and have been extensively developed for road or air transport and are reported on elsewhere.

For instance, the chapter on longitudinal dynamics mainly uses Australian examples as the issues related to longitudinal dynamics cause most problems in heavy haul lines such as those in Australia where very long trains are used to transport bulk freight with extremely high axle loads, sometimes on narrow gauge track.

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The desire to run high-speed trains in this situation has led to the use of highly developed techniques to permit full advantage of the loading gauge to be taken. The issue of standards has been a tricky one due to the vast number of different organisations who set and control railway standards. It has not been possible to provide comprehensive guidance in this area but typical examples of the application of standards have been brought into the handbook where appropriate.

It should be stressed that these are intended only as illustrative examples of how the results of vehicle dynamic analyses can be used, and those with responsibility for safety should check carefully what the relevant current standards are for their work. Professor Wickens was one of the pioneers of these methods and, as director of research at British Rail Research, played a key role in the practical application of vehicle dynamics knowledge to high-speed freight and passenger vehicles.

In Chapter 3, Anna Orlova and Yuri Boronenko outline and explain the basic structure of the railway vehicle and the different types of running gear that are commonly used.

Each of the relevant components is described and the advantages and disadvantages of the different types explained. The key area of any study of railway vehicle behaviour is the contact between the wheels and the rails. All the forces that support and guide the vehicle pass through this small contact patch, and an understanding of the nature of these forces is vital to any analysis of the general vehicle behaviour.

They include an analysis of the normal contact that governs the size and shape of the contact patch and the stresses in the wheel and rail and also the tangential problem where slippage or creep in the contact patch produces the creep forces which accelerate, brake, and guide the vehicle.

The science of tribology is not a new one but has only recently been linked to vehicle dynamics to allow effective prediction of wheel and rail wear, and examples of this from the Stockholm local railway network are presented. Although the main focus of railway vehicle dynamics is traditionally on the vehicle, the track is a key part of the system and in Chapter 6 Tore Dahlberg clearly explains the way that track dynamics can be understood.

The contribution of each of the main components that make up the track to its overall dynamic behaviour is also presented. Chapter 7 covers the unique railway problem of gauging, where the movement of a railway vehicle means that it sweeps through a space that is larger than it would occupy if it moved in a perfectly straight or curved path.

Precise knowledge of this space or envelope is essential to avoid vehicles hitting parts of the surrounding infrastructure or each other. Johnson has developed computer techniques that allow the gauging process to be carried out to permit vehicle designers and operators to ensure safety at the same time as maximising vehicle size and speed, and in this chapter he explains these philosophies and techniques.

Of fundamental concern to all railway engineers is the avoidance of derailment and its potentially catastrophic consequences.

Longitudinal train dynamics are covered by Colin Cole in Chapter 9. This is an aspect of vehicle dynamics that is sometimes ignored, but it becomes of major importance in heavy haul railways where very long and heavy trains lead to extremely high coupling forces between vehicles.

This chapter also covers rolling resistance and braking systems. Chapter 10 deals with noise and vibration problems, which have become of greater concern in recent years. David Thompson and Chris Jones explain the key issues including rolling noise caused by rail surface roughness, impact noise, and curve squeal.

They outline the basic theory required for a study in this area and also show how computer tools can be used to reduce the problem of noise. In Chapter 11, R. Mei summarise the possible ways in which active suspensions can allow vehicle designers to provide advantages that are not possible with passive suspensions. The basic concepts from tilting bodies to active secondary and primary suspension components are explained in detail and with examples. Recent tests on a prototype actively controlled bogie are presented and limitations of the current actuators and sensors are explored before conclusions are drawn about the technology that will be seen in future vehicles.

Computer tools are now widely used in vehicle dynamics and some specialist software packages allow all aspects of vehicle —track interaction to be simulated.

Material in previous chapters is drawn upon to inform the models of suspension elements and wheel — rail contact, and the types of analysis that are typically carried out are described. Typical simulation tasks are presented from the viewpoint of a vehicle designer attempting to optimise suspension performance. Julian Stow and Evert Andersson outline the range of transducers available to the test engineer and the ways that these can be most effectively used to obtain valid and useful data.

Weihua Zhang and his colleagues at Southwest Jiaotong University in China operate what is probably the most important roller rig in the world today and they outline the characteristics of this and other roller rigs and the ways in which they are used.

Chapter 14 also reviews the history of roller rigs, giving summaries of the key details of examples of the main types. Chapter 15 extends the theme to scale testing, which has been used effectively for research into wheel —rail contact.

In this chapter P. Allen describes the possible scaling philosophies that can be used and how these have been applied to scale roller rigs.

Coning and the Kinematic Oscillation Concepts of Curving Hunting and the Empirical Development of the Bogie Interaction between Vehicle and Track Innovations for Improved Steering Wheel —Rail GeometrySince this frequency is proportional to speed, then at low speeds the inertia forces will be small and the main component of the resultant force acting on the wheelset is the restoring force provided by the springs connect- ing the wheelsets to the vehicle body.

But the configuration, suspension and forms of articulation can be varied over a wide range of possibilities, limited mainly by the degree of complexity considered acceptable for each application. If the amplitude is slightly less than that corresponding to the boundary D, oscillations will decay until A is reached. Assessment of the critical speeds of various types of four-wheeled vehicles. A second objective of the study of railway vehicle dynamics is to develop ana- lytical or numerical models describing the mechanics of various phenomena by the simplest model possible.