Experimental solid mechanics is the study of materials to determine their physical properties. This study might include performing a stress analysis or measuring the extent of displacement, shape, strain and stress which a material suffers under controlled conditions. In the last few years there have been remarkable developments in experimental techniques that measure shape, displacement and strains and these sorts of experiments are increasingly conducted using computational techniques.
Experimental Mechanics of Solids is a comprehensive introduction to the topics, technologies and methods of experimental mechanics of solids. It begins by establishing the fundamentals of continuum mechanics, explaining key areas such as the equations used, stresses and strains, and two and three dimensional problems. Having laid down the foundations of the topic, the book then moves on to look at specific techniques and technologies with emphasis on the most recent developments such as optics and image processing. Most of the current computational methods, as well as practical ones, are included to ensure that the book provides information essential to the reader in practical or research applications.
Key features:
- Presents widely used and accepted methodologies that are based on research and development work of the lead author
- Systematically works through the topics and theories of experimental mechanics including detailed treatments of the Moire, Speckle and holographic optical methods
- Includes illustrations and diagrams to illuminate the topic clearly for the reader
- Provides a comprehensive introduction to the topic, and also acts as a quick reference guide
This comprehensive book forms an invaluable resource for graduate students and is also a point of reference for researchers and practitioners in structural and materials engineering.
Autorentext
Cesar & Federico Sciammarella, University of Illinois, USA Cesar A Sciammarella is Adjunct Professor in the Department of Mechanical Engineering, University of Illinois, USA. In the past he has worked as a consultant for companies including: General Motors, Goodyear, Honeywell Corporation, Rand Corporation, Rockwell International, Sundstran, Uniroyal Tires, IBM, Tryodyne, Samsung, Case Corporation. A renowned experimentalist, his research currently focuses on developing techniques in solid mechanics and he has spoken at many conferences and published prolifically in journals which include Strain; Optical Engineering; SEM Conference on Experimental Mechanics and Journal of Strain Analysis for Engineering Design. Federico Sciammarella is Assistant Professor in the Department of Mechanical Engineering, University of Illinois. His research interests centre upon using optical methods for characterization of materials and structures including failure analysis. Over the past five years he has written multiple journal and conference research papers.
Inhalt
About the Authors xvii
Preface xix
Foreword xxi
1 Continuum Mechanics - Historical Background 1
1.1 Definition of the Concept of Stress 4
1.2 Transformation of Coordinates 5
1.3 Stress Tensor Representation 6
1.4 Principal Stresses 8
1.5 Principal Stresses in Two Dimensions 10
1.6 The Equations of Equilibrium 11
1.7 Strain Tensor 13
1.8 Stress - Strain Relations 15
1.9 Equations of Compatibility 18
References 19
2 Theoretical Stress Analysis - Basic Formulation of Continuum Mechanics. Theory of Elasticity 21
2.1 Introduction 21
2.2 Fundamental Assumptions 21
2.3 General Problem 22
2.4 St. Venant's Principle 25
2.5 Plane Stress, Plane Strain 28
2.6 Plane Stress Solution of a Simply Supported Beam with a Uniform Load 30
2.7 Solutions in Plane Strain and in Plane Stress 33
2.8 The Plane Problem in Polar Coordinates 35
2.9 Thick Wall Cylinders 36
References 39
3 Strain Gages - Introduction to Electrical Strain Gages 41
3.1 Strain Measurements - Point Methods 41
3.2 Electrical Strain Gages 42
3.3 Basics of Electrical Strain Gages 43
3.4 Gage Factor 45
3.5 Basic Characteristics of Electrical Strain Gages 48
3.6 Errors Due to the Transverse Sensitivity 54
3.7 Errors Due to Misalignment of Strain Gages 58
3.8 Reinforcing Effect of the Gage 60
3.9 Effect of the Resistance to Ground 61
3.10 Linearity of the Gages. Hysteresis 63
3.11 Maximum Deformations 64
3.12 Stability in Time 64
3.13 Heat Generation and Dissipation 64
3.14 Effect of External Ambient Pressure 65
3.15 Dynamic Effects 67
References 71
4 Strain Gages Instrumentation - TheWheatstone Bridge 75
4.1 Introduction 75
References 109
5 Strain Gage Rosettes: Selection, Application and Data Reduction 111
5.1 Introduction 111
5.2 Errors, Corrections, and Limitations for Rosettes 119
5.3 Applications of Gages to Load Cells 119
References 121
6 Optical Methods - Introduction 123
6.1 Historical Perspective and Overview 123
6.2 Fundamental Basic Definitions of Optics 127
6.3 The Electromagnetic Theory of Light 128
6.4 Properties of Polarized Light 137
6.5 The Jones Vector Representation 138
6.6 Light Intensity 141
6.7 Refraction of the Light 141
6.8 Geometrical Optics. Lenses and Mirrors 146
References 154
7 Optical Methods - Interference and Diffraction of Light 155
7.1 Connecting Light Interference with Basic Optical Concepts 155
7.2 Light Sources 155
7.3 Interference 161
7.4 Interferometers 166
7.5 Diffraction of the Light 171
References 181
8 Optical Methods - Fourier Transform 183
8.1 Introduction 183
8.2 Simple Properties 185
8.3 Transition to Two Dimensions 187
8.4 Special Functions 188
8.5 Applications to Diffraction Problems 191
8.6 Diffraction Patterns of Gratings 193
8.7 Angular Spectrum 195
8.8 Utilization of the FT in the Analysis of Diffraction Gratings 199
References 205
9 Optical Methods - Computer Vision 207
9.1 Introduction 207
9.2 Study of Lens Systems 208
9.3 Lens System, Coordinate Axis and Basic Layout 210
9.4 Diffraction Effect on Images 211
9.5 Analysis of the Derived Pupil Equations for Coherent Illumination 216
9.6 Imaging with Incoherent Illumination 217
9.7 Digital Cameras 230
9.8 Illumination Systems 242
9.9 Imaging Processing Systems 245
9.10 Getting High Quality Images 246
References 249
10 Optical Methods - Discrete Fourier Transform 251
10.1 Extension to Two Dimensions 253
10.2 The Whittaker-Shannon Theorem 257
10.3 General Representation of the Signals Subjected to Analysis 261
10.4 Computation of the Phase of the Fringes 271
10.5 Fringe Patterns Singularities 276
10.6 Extension of the Fringes beyond Boundaries 279
References 283
11 Photoelasticity - Introduction 285
11.1 Introduction 285
11.2 Derivation of the Fundamental Equations 286
11.3 Wave Plates 291
11.4 Polarizers 293
11.5 Instrument Matrices 294
11.6 Polariscopes 296
11.7 Artificial Birefringence 304
11.8 Polariscopes 307
11.9 Equations of the Intensities of the Plane Polariscope and the Circular Polariscope for a Stressed Plate 309
References 311
12 Photoelasticity Applications 313
12.1 Calibration Procedures of a Photoelastic Material 313
12.2…