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2021 | Book

Mechanics of Fretting and Fretting Fatigue

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About this book

This book, which has only one very distant forerunner authored by David A. Hills with David Nowell, represents a very big step that is the quantification of these problems and represents the twenty-five years’ worth of work which have gone on at Oxford since the first book on the subject. Fatigue (popularly ‘metal fatigue’) is the primary failure mode of all machines, engines, transmissions and indeed almost all mechanical devices. The propagation of cracks is well understood and is treated in the subject Fracture Mechanics. By contrast, the nucleation of cracks is very hard to quantify and this remains the case with so-called ‘free initiation’ and, to a lesser extent, at cracks nucleated from stress raising features. But the third form of nucleation, where cracks start from the edges of rubbing components, that is, at joints, is potentially a very much better-defined environment, and therefore, the problem is amendable to attack by applied mechanics and experiment. The contents are of value both to those embarking on research on the subject and to practitioner in industry.

Table of Contents

Frontmatter
Chapter 1. Some Fundamentals
Abstract
Sliding contacts in engineering are always, properly, lubricated in some way, and therefore little damage should ensue. But when we have notionally stationary contacts, which may be bolted or established by some other methods, such as the generation of centrifugal loads in a gas turbine, or hydraulic action in a wellhead locking segment, secondary, fluctuating loads may cause tiny amounts of differential movement, or borrowing a word with an associated common usage ‘fretting’.
David A. Hills, Hendrik N. Andresen
Chapter 2. Plane Elasticity and Half-Plane Contacts
Abstract
The basis of fundamental contact solutions should be ‘exact’ elasticity solutions, where we sacrifice the realism of details of the geometry of a real contact by replacing them with something quite idealised, but then obtain a solution that is precise.
David A. Hills, Hendrik N. Andresen
Chapter 3. Williams’ Solution
Abstract
Most books on the subject of contact mechanics concentrate on those problems which can be attacked by half-plane or half-space theory, so that this really restricts attention to incomplete contacts, and where there is plenty of material in the neighbourhood of the contact for the half-plane (space) idealisation to be appropriate.
David A. Hills, Hendrik N. Andresen
Chapter 4. Half-Plane Partial Slip Contact Problems
Abstract
Contacts arise in almost all mechanical assemblies and a number of heavily loaded contacts have rounded edges, which often make it possible to represent them, at least approximately, using half-plane theory. Examples include swash plate assemblies in helicopter rotor heads, dovetail roots in gas turbine fan blades, and in the locking segments used to fasten risers to wellheads in subsea installations. These assemblies suffer complicated load histories so that the contacts invariably transfer normal and tangential loads. In fact, there are only three possible states an incomplete contact subject to normal and tangential loading can be in.
David A. Hills, Hendrik N. Andresen
Chapter 5. Complete Contacts and Their Behaviour
Abstract
It is relatively unusual to encounter ‘complete’ contacts in a mechanical engineering assembly. Designers intuitively appreciate that having sharp-edged precision components fastened together may spell trouble because they recognise that the state of stress is very high near such features.
David A. Hills, Hendrik N. Andresen
Chapter 6. Representation of Half-Plane Contact Edge Behaviour by Asymptotes
Abstract
When we were looking at complete contacts (Chap. 5), the lack of an elasticity formulation for the contact as a whole meant that, of necessity, we had to concentrate our attention on the contact edges where a partly closed-form solution in the form of Williams’ analysis (Chap. 3) was available for us to build on.
David A. Hills, Hendrik N. Andresen
Chapter 7. Crack Propagation, Nucleation and Nucleation Modelling
Abstract
A majority of this book is concerned with describing and analysing the behaviour of contacts, and the effects of local frictional slip. Those results, by themselves, are sufficient to quantify the damping effects afforded, and their influence on limiting the effects of vibration.
David A. Hills, Hendrik N. Andresen
Chapter 8. Experiments to Measure Fretting Fatigue Strength
Abstract
In plain fatigue, we would normally think of there being two basic approaches; (a) ‘total life’ where the crack is freely initiated and the life of the component is correlated with the nominal stress present in the form of a so-called S-N curve, and (b) fracture mechanics where an attempt is made to separate the number of cycles needed to nucleate a crack and those needed to propagate it.
David A. Hills, Hendrik N. Andresen
Chapter 9. Fretting Strength
Abstract
In earlier chapters, we have developed methods of stress analysis to determine the contact pressure and shear traction distributions for a wide range of contacts, incomplete and complete, and for a wide range of loading histories where history dependence is exhibited, as it is in all frictional half-plane contacts.
David A. Hills, Hendrik N. Andresen
Backmatter
Metadata
Title
Mechanics of Fretting and Fretting Fatigue
Authors
Prof. David A. Hills
Dr. Hendrik N. Andresen
Copyright Year
2021
Electronic ISBN
978-3-030-70746-0
Print ISBN
978-3-030-70745-3
DOI
https://doi.org/10.1007/978-3-030-70746-0

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