Basic lubrication theory (2nd edition): by Alastair Cameron. Ellis Horwood Series in Engineering Science, Chichester, 1976. xx + 195 pages, ISBN 0-85312-057-9, hardback £8.00

Journal of Mechanical Working Technology, 4 (1980) 191--201 191 ©Elsevier Scientific Publishing Company, Amsterdam -- Printed in The Netherlands Book Reviews Basic Lubrication Theory (2nd edition), by Alastair Cameron. Ellis Horwood Series in Engineering Science, Chichester, 1976. xx + 195 pages, ISBN 0- 85312-057-9, hardback £8.00. This second edition of a most valuable text to any engineer or scientist wishing to obtain an understanding of the theory of full film lubrication, is unchanged from the first edition, with the exception of one chapter. The book has been revived from the 'out-of-print' class by its new publisher. The book provides a clear, concise, comprehensive development of lubrication theory, simplifying the mathematics wherever possible. It is a most useful text for any engineering undergraduate, post-graduate or practising engineer wishing to understand the theory of full film lubrication. The brief introduction illustrates the role of a lubricant in carrying load and mentions the mechanisms of boundary lubrication and the hydrodynamic wedge. The concepts having been presented, each chapter then discusses and analyses the various aspects of full film lubrication. Before any analysis in lubrication theory can be understood and applied with any conviction, a full understanding of viscosity and the formulae from which all full film lubrication theory stems -- namely Reynolds equation -- has to be obtained. The second and third chapters deal with both of these topics respectively. Viscosity is dealt with in some detail, with clear distinc- tion between dynamic and kinematic viscosity. Both quantities are examined dimensionally to clarify any problems with units which might otherwise occur. Theoretical relationships are developed for the effect of temperature on viscosity and the widely used ASTM chart for mineral oils is described. Viscosity Index, grades of oil, effect of pressure, and polymer thickening of oil are discussed. The chapter concludes by looking at the viscosity of gases and the effect of compressibility and thermal expansion on viscosity. Reynolds equation is developed in two quite different ways. In a simpli- fied approach an expression for the pressure generated in a converging clear- ance is developed from dimensional analyses. This serves to familiarize the reader with the lubrication mechanism with the minimum amount of mathe- matical analysis. The more conventional derivation of the full Reynolds equa- tion follows, commencing with the continuity of flow and equilibrium of an element. Prior to examining the theory involved in hydrodynamic journal and thrust bearings, chapter four deals with the derivation of the pressure distribution in a converging-diverging clearance. This chapter has been re-written in the second edition to express the clearance in secant form. This allows the mathe- matical analyses to be simplified without creating a discontinuity in the clear- ance. The significance of large negative pressures occuring in the analyses are discussed and two techniques of eliminating them are examined and compared. 192 From the pressure distribution, the load, centre of pressure and friction are derived. The theory associated with various types of hydrodynamic thrust bearings is undertaken in chapter five. This chapter is basically the application of earlier techniques now applied to the tilting and fixed inclined pad, tapered land and Rayleigh step bearing. In all cases side leakage is neglected by assuming the bearings to be infinitely long. An insight into the lubrication of rolling element bearings and gears is pro- vided by chapter six, which deals with the lubrication of discs. This analysis involves the substitution of the clearance expressions into Reynolds equation to obtain the pressure distribution and subsequently the load carrying capacity. This chapter is an extension of chapter four and concludes by briefly examining the lubrication of spheres. Chapter seven deals with the hydrodynamic journal bearing in some depth. Bearings subjected to steady loads are analysed in detail with expressions for load capacity, attitude angle, oil flow, friction and the effect of tilt all derived. Much of the bulk of the analysis has been reduced by including at the end of the chapter an appendix of the integrals required. The next three chapters deal with other important factors in journal bearings which merit chapters in themselves, if only to attract the reader's attention to their importance. They are 'Heat in Bearings', 'Alternating Loads and Squeeze Films' and most important of all 'Oil Whirl', which is dealt with in some detail. Porous bearings are a particular form of journal bearing and a short chapter deals with the derivation of the equation for pressure distribution. The second principal class of full film bearings are hydrostatic. Chapter twelve deals with this type -- sometimes referred to as 'Externally pressurized bearings'. The classical circular-step thrust bearing is analysed in detail. The role and action of compensators are discussed briefly. Since the first edition of this book, much work has been published on hydrostatic lubrication and it is a little disappointing that this section has not been extended for this second edition. Some analysis of the hydrostatic journal bearing could be useful and interesting to readers hoping to gain an overall understanding of basic lubrication theory. An insight into Elastohydrodynamic lubrication is provided by chapter thirteen. This deals with the elastic deformation of surfaces subjected to high pressures, and, incorporating viscosity changes due to the pressures, develops modified pressure and clearance profiles. A simplified but relevant technique is employed to obtain relationships in this section. The following three chapters discuss 'Friction and Heat', 'Boundary Ex- treme Pressure Lubrication and Scuffing', and 'Experimental Techniques' and the final chapter provides the reader with a range of problems to test his un- derstanding of the subject! In all, it is a well-written and presented text which should provide the reader with some real understanding of this important aspect of lubrication, 193 but it is unfortunate that hydrostatic lubrication was not pursued to a greater depth. Throughout the book, which is quite mathematical by its very nature, the analyses have been simplified wherever possible to assist the reader in understanding the lubrication principles without becoming lost in the mathe- matics. The book was born out of another written by the same author, "Principles of Lubrication", which is a more advanced and comprehensive book than that here reviewed; readers may well graduate to this after gaining an apprecia- tion of Basic Lubrication Theory. M.J. NEWTON Engineering Graphics Modelling, by E. Tjalve, M.M. Andreasen and F. Frack- mann Schmidt, The Butterworth Group, Sevenoaks, Kent, 1979. English translation edited by G. Pitt. 119 pages, ISBN 0- -408- -00305:7 softcover £4.79. This book sets out to describe the novel approach to the teaching of mechanical design draughtsmanship which has been developed over a period of years by. the authors, who are members of the Laboratory of Engineering Design at the Technical University of Denmark. The initial part of the text discusses drawing and design in general terms and leads up to the focal point of the book, namely, the "Morphology of Drawing". The structure of the book is based on this morphology, which breaks down the drawing process for design into four main elements: these are the modelled properties, receiver, code and drawing technique. The main sections of the book are devoted to the explanation of the meaning and sig- nificance of these terms, using an abundance of good sketches and drawings set out on worksheets. A final section illustrates, with examples, the main types of drawing. The illustrative drawings used in the text cover almost every type of drawing/diagram likely to be encountered in engineering, including line diagrams, block diagrams, graphs, charts, exploded views, two- and three- dimensional sketches and engineering drawings. Whilst it could be argued that this more generalised philosophy to drawing and sketching represents a more coherent approach to the subject, it does appear to unnecessarily complicate the problem (as recognised in the preface of the book) that students face in perceiving in three dimensions and, associated with this, their difficulty in ex- pressing themselves with sketches and conventional drawings. The broad scope of this book clouds this central issue. It is difficult, therefore, to imagine that this book would be appropriate for students as a textbook: however, to those involved in teaching drawing at all levels, it does present a new approach to the subject. B.G. SINGER