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Aircraft Structures for Engineering Students pdf

Aircraft Structures for Engineering Students is the leading self contained aircraft structures course text. It covers all fundamental subjects, including elasticity, structural analysis, airworthiness and aeroelasticity. Now in its fourth edition, the author has revised and updated the text throughout and added new case study and worked example material to make the text even more accessible.

Features – Aircraft Structures for Engineering Students

  • The leading Aircraft Structures text, covering a complete course from basic structural mechanics to finite element analysis
  • Enhanced pedagogy with additional case studies, worked examples and home work exercises

Readership – Aircraft Structures for Engineering Students

Undergraduate and postgraduate students of aerospace and aeronautical engineering; Also suitable for professional development and training courses

Contents – Aircraft Structures for Engineering Students

Part A Fundamentals of Structural Analysis A I Elasticity

  1. Basic elasticity 1.1 Stress 1.2 Notation for forces and stress 1.3 Equations of equilibrium 1.4 Plane stress 1.5 Boundary conditions 1.6 Determination of stresses on inclined planes 1.7 Principal Stresses 1.8 Mohr’s circle of stress 1.9 Strain 1.10 compatibility equations 1.11 Plane strain 1.12 Determination of strains on inclined planes 1.13 Principal strains 1.14 Mohr’s circle of strain 1.15 Stress-strain relationships 1.16 Experimental measurement of surface strains    
  2. Two-dimensional problems in elasticity 2.1 Two-dimensional problems 2.2 Stress functions 2.3 Inverse and semi-inverse methods 2.4 St. Venant’s principle 2.5 Displacements 2.6 Bending of an end-loaded cantilever   
  3. Torsion of solid sections 3.1 Prandtl stress function solution 3.2 St. Venant warping function solution 3.3 The membrane analogy 3.4 Torsion of a narrow rectangular strip

A II Virtual Work, Energy and Matrix Methods

  1. Virtual work 4.1 Work 4.2 Principle of virtual work 4.2.1 For a particle 4.2.2 For a rigid body 4.2.3 Virtual work in a deformable body 4.2.4 Work done by internal force systems 4.2.5 Virtual work due to external force systems 4.3.6 Use of virtual force systems 4.3 Applications of the principle of virtual work   
  2. Energy methods 5.1 Strain energy and complementary energy 5.2 The principle of the stationary value of the total complementary energy 5.3 Application to deflection problems 5.4 Application to the solution of statically indeterminate systems 5.5 Unit load method 5.6 Flexibility method 5.6.1 Self Straining method 5.7 Total potential energy 5.8 the principle of the stationary value of the total potential energy 5.9 Principle of superposition 5.10 Reciprocal theorems 5.11 Temperature effects   
  3. Matrix methods 6.1 Notation 6.2 Stiffness matrix for an elastic spring 6.3 Stiffness matrix for two elastic springs in line 6.4 Matrix analysis of pin-jointed frameworks 6.5 Application to statically indeterminate frameworks 6.6 Matrix analysis of space frames 6.7 Stiffness matrix for a uniform beam 6.8 Finite element method for continuum structures 6.8.1 Stiffness matrix for a beam-element 6.8.2 Stiffness matrix for a triangular finite element 6.8.3 Stiffness matrix for a quadrilateral element

A III Thin Plate Theory

  1. Bending of thin plates 7.1 Pure Bending of thin plates 7.2 Plates subjected to bending and twitsting 7.3 Plates subjected to a distributed transverse load 7.3.1 The simply supported edge 7.3.2 The built-in edge 7.3.3 The free edge 7.4 Combined bending and in-plane loading of a thin rectangular plate 7.5 Bending of thin plates having a small initial curvature 7.6 Energy method for the bending of thin plates 7.6.1 Strain energy produced by bending and twisting 7.6.2 Potential energy of a transverse load 7.6.3 Potential energy of in-plane loads

A IV Structural Instability

  1. Columns 8.1 Euler buckling of columns 8.2 Inelastic buckling 8.3 Effect of initial imperfections 8.4 Stability of beams under transverse and axial loads 8.5 Energy method for the calculation of buckling loads in columns   
  2. Thin plates 9.1 Buckling of thin plates 9.2 Inelastic buckling of plates 9.3 Experimental determination of critical load for a flat plate 9.4 Local instability 9.5 Instability of stiffened panels 9.6 Failure stress in plates and stiffened panels 9.7 Tension field beams 9.7.1 Complete diagonal 9.7.2 Incomplete diagonal tension 9.7.3 Post buckling behaviour   
  3. Structural Vibration 10.1 Oscillation of mass/spring systems 10.2 Oscillation of beams 10.3 Approximate methods for determining natural frequencies   

Part B Analysis of Aircraft Structures B I Principles of Stressed Skin Construction

  1. Materials 11.1 Aluminium alloys 11.2 Steel 11.3 Titanium 11.4 Plastics 11.5 Glass 11.6 Composites 11.7 Properties of materials   
  2. Structural components of aircraft 12.1 Loads on components 12.2 Function of components 12.3 Fabrication of components 12.4 Connections Structural Vibration   

BII Airworthiness and Airframe Loads

  1. Airworthiness 13.1 Factors of safety – flight envelope 13.2 Load factor determination 13.2.1 Limit load 13.2.2 Structural deterioration and uncertainties in design 13.2.3 Variation in structural strength 13.2.4 Fatigue    
  2. Airframe loads 14.1 Inertia loads 14.2 Symmetric manoeuvre loads 14.2.1 Level flight 14.2.2 General case 14.3 Normal acceleration associated with various types of manoeuvre 14.3.1 Steady pull-out 14.3.2 Correctly banked turn 14.4 Gust loads 14.4.1 Sharp-edged gust 14.4.2 The “graded” gust 14.4.3 Gust envelope   
  3. Fatigue 15.1 Safe life and fail safe structures 15.2 Designing against fatigue 15.3 Fatigue strength of components 15.4 Prediction of aircraft fatigue life 15.5 Creep 15.6 Crack propagation   

B III Bending, Shear and Torsion of Thin-Walled Beams

  1. Bending of open and closed, Thin-Walled Beams 16.1 Symmetrical Bending 16.1.1 Assumptions 16.1.2 Direct Stress Distribution 16.1.3 Anticlastic Bending 16.2 Unsymmetrical Bending 16.2.1 Sign Conventions and notation 16.2.2 Resolution of bending moments 16.2.3 Direct Stress distribution due to bending 16.2.4 Position of the neutral axis 16.2.5Load intensity, shear force and bending moment relationships, general case 16.3 Deflections due to bending 16.4 Calculation of Section Properties 16.4.1 Parallel Axes Theorem 16.4.2 Theorem of Perpendicular Axes 16.4.3 Second Moments of Area of Standard Sections 16.5 Application of bending theory    
  2. Shear of beams 17.1 General stress, strain and displacement relationships 17.2 Open section beams 17.2.1 Shear centre 17.3 Closed section beams 17.3.1 Twist and warping 17.3.2 Shear centre    
  3. Torsion of beams 18.1 Closed section beams 18.1.1 Displacements associated with the Bredt-Batho shear flow 18.1.2 Condition for zero warping 18.2 Torsion of open section beams 18.2.1 Warping of cross-section   
  4. Combined open and closed section beams 19.1 Bending 19.2 Shear 19.3 Torsion    
  5. Structural Idealisation 20.1 Principle 20.2 Idealisation of a panel 20.3 Effect of idealisation on the analysis of open and closed section beams 20.3.1 Bending of open and closed section beams 20.3.2 Shear of open section beams 20.3.3 Shear of closed section beams 20.3.4 Alternative method for the calculation of shear flow distribution 20.3.5 Torsion of open and closed section beams   

B IV Stress Analysis of Aircraft Components

  1. Wing spars and box beams 21.1 Tapered wing spar 21.2 Open and closed section box beams 21.3 Beams having variable stringer areas  
  2. Fuselages 22.1 Bending 22.2 Shear 22.3 Torsion 22.4 Effect of cut-outs   
  3. Wings 23.1 Three-boom shell 23.2 Bending 23.3 Torsion 23.4 Shear 23.5 Shear centre 23.6 Tapered wings 23.7 Deflections 23.8 Effect of cut-outs   
  4. Fuselage frames and wing ribs 24.1 Principles of Stiffener/web construction 24.2 Fuselage frames 24.3 Wing ribs   
  5. Laminated composite structures 25.1 Elastic constants of simple lamina 2.5.2 Stress-strain relationships for an orthotropic ply (macro-approach) 25.2.1 Specially orthotropic ply 25.2.2 Generally orthotropic ply 25.3 Thin-walled composite beams 25.3.1 Axial load 25.3.2 Bending 25.3.3 Shear 25.3.4 Torsion   

BV Structural and Loading Discontinuities

  1. Closed section beams 26.1 General aspects 26.2 Shear distribution at a built-in end 26.3 Torsion of a rectangular section beam 26.4 Shear lag   
  2. Open section beams 27.1 I-section beam subjected to torsion 27.2 Arbitrary section beam subjected to torsion 27.3 Distributed torque loading 27.4 General system of loading 27.5 Moment couple (bimoment) 27.5.1 Shear flow due to MT    

B VI Introduction to Aeroelasticity

  1. Wing problems 28.1 Types of problem 28.2 Load distribution and divergence 28.2.1 Wing torsional divergence (two-dimensional) 28.2.1 Wing torsional divergence (finite wing) 28.2.3 Swept wing divergence 28.3 Control effectiveness and reversal 28.3.1 Aileron effectiveness and reversal (two-dimensional) 28.3.2 Aileron effectiveness and reversal (finite wing) 28.4 Introduction to Flutter 28.4.1 Coupling 28.4.2 Critical flutter speed 28.4.3 Prevention of flutter 28.4.4 Experimental determination of flutter speed. 28.4.5 Control surface flutter

APPENDIX

Case Study : Design of an Aircraft Fuselage

Requirement: The aircraft

A1. Specification A2. Data A3. Initial calculations A4. Balancing out calculations A5. Fuselage loads A6. Fuselage design calculations   

Details – Aircraft Structures for Engineering Students

No. of pages: 824Language: EnglishCopyright: © Butterworth-Heinemann 2007Published: 8th March 2007Imprint: Butterworth-HeinemanneBook ISBN: 9780080488318

Author – Aircraft Structures for Engineering Students

T.H.G. Megson

T.H.G. Megson is a professor emeritus with the Department of Civil Engineering at Leeds University (UK). For Elsevier he has written the market leading Butterworth Heinemann textbooks Aircraft Structures for Engineering Students and Introduction to Aircraft Structural Analysis (a briefer derivative of the aircraft structures book), as well as the text/ref hybrid Structural and Stress Analysis.

Preface

During my experience of teaching aircraft structures I have felt the need for a textbook written specifically for students of aeronautical engineering. Although there have been a number of excellent books written on the subject they are now either out of date or too specialist in content to fulfil the requirements of an undergraduate textbook.

My aim, therefore, has been to fill this gap and provide a completely self-contained course in aircraft structures which contains not only the fundamentals of elasticity and aircraft structural analysis but also the associated topics of airworthiness and aeroelasticity. The book in intended for students studying for degrees, Higher National Diplomas and Higher National Certificates in aeronautical engineering and will be found of value to those students in related courses who specialize in structures.

The subject matter has been chosen to provide the student with a textbook which will take him from the beginning of the second year of his course, when specialization usually begins, up to and including his final examination. I have arranged the topics so that they may be studied to an appropriate level in, say, the second year and then resumed at a more advanced stage in the final year; for example, the instability of columns and beams may be studied as examples of structural instability at second year level while the instability of plates and stiffened panels could be studied in the final year. In addition, I have grouped some subjects under unifying headings to emphasize their interrelationship; thus, bending, shear and torsion of open and closed tubes are treated in a single chapter to underline the fact that they are just different loading cases of basic structural components rather than isolated topics.

I realize however that the modern trend is to present methods of analysis in general terms and then consider specific applications. Nevertheless, I feel that in cases such as those described above it is beneficial for the student’s understanding of the subject to see the close relationships and similarities amongst the different portions of theory. Part I of the book, ‘Fundamentals of Elasticity’, Chapters 1–6, includes sufficient elasticity theory to provide the student with the basic tools of structural analysis. The work is standard but the presentation in some instances is original. In Chapter 4 I have endeavoured to clarify the use of energy methods of analysis and present a consistent, but general, approach to the various types of structural problem for which energy methods are employed. Thus, although a variety of methods are discussed, emphasis is placed on the methods of complementary and potential energy. Overall, my intention has been to given some indication of the role and limitations of each method of analysis.

Part II, ‘Analysis of Aircraft Structures’, Chapters 7–11, contains the analysis of the thin-walled, cellular type of structure peculiar to aircraft. In addition, Chapter 7 includes a discussion of structural materials, the fabrication and function of structural components and an introduction to structural idealization. Chapter 10 discusses the limitations of the theory presented in Chapters 8 and 9 and investigates modifications necessary to account for axial constraint effects. An introduction to computational methods of structural analysis is presented in Chapter 11 which also includes some elementary work on the relatively modern finite element method for continuum structures. Finally, Part III, ‘Airworthiness and Aeroelasticity’, Chapters 12 and 13, are self explanatory. Worked examples are used extensively in the text to illustrate the theory while numerous unworked problems with answers are listed at the end of each chapter; S.I. units are used throughout. I am indebted to the Universities of London (L.U.) and Leeds for permission to include examples from their degree papers and also the Civil Engineering Department of the University of Leeds for allowing me any facilities I required during the preparation of the manuscript. I am also extremely indebted to my wife, Margaret, who willingly undertook the onerous task of typing the manuscript in addition to attending to the demands of a home and our three sons, Andrew, Richard and Antony

Preface to Fourth Edition

I have reviewed the three previous editions of the book and decided that a major overhaul would be beneficial, particularly in the light of developments in the aircraft industry and in the teaching of the subject. Present-day students prefer numerous worked examples and problems to solve so that I have included more worked examples in the text and more problems at the end of each chapter. I also felt that some of the chapters were too long. I have therefore broken down some of the longer chapters into shorter, more ‘digestible’ ones. For example, the previous Chapter 9 which covered bending, shear and torsion of open and closed section thin-walled beams plus the analysis of combined open and closed section beams, structural idealization and deflections now forms the contents of Chapters 16–20. Similarly, the Third Edition Chapter 10 ‘Stress Analysis of Aircraft Components’is now contained in Chapters 21–25 while ‘Structural Instability’, Chapter 6 in the Third Edition, is now covered by Chapters 8 and 9.

In addition to breaking down the longer chapters I have rearranged the material to emphasize the application of the fundamentals of structural analysis, contained in Part A, to the analysis of aircraft structures which forms Part B. For example, Matrix Methods, which were included in ‘Part II, Aircraft Structures’ in the Third Edition are now included in Part A since they are basic to general structural analysis; similarly for structural vibration. Parts of the theory have been expanded. In Part A, virtual work now merits a chapter (Chapter 4) to itself since I believe this powerful and important method is worth an indepth study. The work on tension field beams (Chapter 9) has become part of the chapter on thin plates and has been extended to include post-buckling behaviour. Materials, in Part B, now contains a section on material properties while, in response to readers’ comments, the historical review has been discarded. The design of rivetted connections has been added to the consideration of structural components of aircraft in Chapter 12 while the work on crack propagation has been extended in Chapter 15. The method of successive approximations for multi-cellular wings has been dropped since, in these computer-driven times, it is of limited use and does not advance an understanding of the behaviour of structures. On the other hand the study of composite structures has been expanded as these form an increasing part of a modern aircraft’s structure. Finally, a Case Study, the design of part of the rear fuselage of a mythical trainer/semiaerobatic aeroplane is presented in the Appendix to illustrate the application of some of the theory contained in this book.

I would like to thank Jonathan Simpson of Elsevier who initiated the project and who collated the very helpful readers’ comments, Margaret, my wife, for suffering the long hours I sat at my word processor, and Jasmine, Lily, Tom and Bryony who are always an inspiration.

Affiliations and Expertise

Department of Civil Engineering, Leeds University, UK

Reviews

This is an excellent book and should find a place on the shelf of any student or practising engineer involved in aircraft structural analysis. I can recommend it to the aeronautical community without reservation – The Aeronautical Journal, October 2001 “As an introduction to the problems encountered in the structural design of modern aircraft, Megson’s book can be recommended to both students and those engaged in structural analysis aerospace design offices.” – Aerospace

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