Experimental Mechanics: An Introduction

Preface
Contents
About the Author
1 Electrical Resistance Strain Gages
	1.1 Introduction
	1.2 Basic Principles
	1.3 Bonded Resistance Strain Gages
	1.4 Transverse Sensitivity and Gage Factor
	1.5 Electrical Circuits
		1.5.1 Introduction
		1.5.2 The Potentiometer Circuit
		1.5.3 The Wheatstone Bridge
	1.6 Strain Gage Rosettes
	Further Readings
2 Fundamentals of Optics
	2.1 Introduction
	2.2 Historical Overview
	2.3 Light Sources, Wave Fronts, and Rays
	2.4 Reflection and Mirrors
		2.4.1 Reflection
		2.4.2 Plane Mirrors
		2.4.3 Spherical Mirrors
	2.5 Refraction
	2.6 Thin Lenses
	2.7 The Wave Nature of Light—Huygens’ Principle
	2.8 Electromagnetic Theory of Light
	2.9 Polarization
	2.10 Interference
		2.10.1 Introduction
		2.10.2 Interference of Two Linearly Polarized Beams
		2.10.3 Young’s Double-Slit Experiment
		2.10.4 Multi-slit Interference
		2.10.5 Interference of Two Plane Waves
		2.10.6 Change of Phase upon Reflection—Thin Films
		2.10.7 Dispersion
	2.11 Diffraction
		2.11.1 Introduction
		2.11.2 Single Slit Diffraction
		2.11.3 Two-Slit Diffraction
		2.11.4 The Diffraction Grating
		2.11.5 Diffraction by a Circular Aperture
		2.11.6 Limit of Resolution
		2.11.7 Fraunhofer Diffraction as a Fourier Transform
		2.11.8 Optical Spatial Filtering
	2.12 Camera
	Further Readings
3 Geometric Moiré
	3.1 Introduction
	3.2 Terminology
	3.3 The Moiré Phenomenon
	3.4 Mathematical Analysis of Moiré Fringes
	3.5 Relationships Between Line Grating and Moiré Fringes
	3.6 Moiré Patterns Formed by Circular, Radial and Line Gratings
	3.7 Measurement of In-Plane Displacements
	3.8 Measurement of Out-Of-Plane Displacements
	3.9 Measurement of Out-Of-Plane Slopes
	3.10 Sharpening of Moiré Fringes
	3.11 Moiré of Moiré
	Further Readings
4 Coherent Moiré and Moiré Interferometry
	4.1 Introduction
	4.2 Superposition of Two Diffraction Gratings
	4.3 Moiré Patterns
	4.4 Optical Filtering and Fringe Multiplication
	4.5 Advantages Offered by Coherent Moiré
	4.6 Moiré Interferometry
		4.6.1 Introduction
		4.6.2 Optical Arrangement
		4.6.3 The Method
		4.6.4 Determination of Strains
	Further Readings
5 Moiré Patterns Formed by Remote Gratings
	5.1 Introduction
	5.2 Geometric Moiré Methods
	5.3 The Coherent Grading Sensor (CGS) Method
		5.3.1 Introduction
		5.3.2 Experimental Arrangement
		5.3.3 Governing Equations
	5.4 Comparison of the Geometric Moiré and the CGS Method
	Further Readings
6 The Method of Caustics
	6.1 Introduction
	6.2 General Equations for Reflecting Surfaces
	6.3 The Ellipsoid Mirror
	6.4 Intensity Distribution of Light Rays Reflected or Transmitted by a Transparent Specimen
	6.5 Stress-Optical Equations
	6.6 Crack Problems
		6.6.1 Introduction
		6.6.2 Principle of the Method
		6.6.3 Opening-Mode Loading
		6.6.4 Mixed-Mode Loading
		6.6.5 Anisotropic Materials
		6.6.6 The State of Stress Near the Crack Tip
		6.6.7 Comparison of the Method of Caustics and Photoelasticity
	Further Readings
7 Photoelasticity
	7.1 Introduction
	7.2 Plane Polariscope
	7.3 Circular Polariscope
	7.4 Isoclinics
	7.5 Isochromatics
	7.6 Isochromatics with White Light
	7.7 Properties of Isoclinics
	7.8 Properties of Isochromatics
	7.9 Compensation Methods
		7.9.1 Introduction
		7.9.2 The Tension/Compression Specimen
		7.9.3 Babinet and Babinet-Soleil Compensators
		7.9.4 Sernarmont Compensation Method
		7.9.5 Tardy Compensation Method
	7.10 Determination of the Photoelastic Constant fs
	7.11 Stress Separation
	7.12 Fringe Multiplication and Sharpening
	7.13 Transition From Model to Prototype
	7.14 Three-Dimensional Photoelasticity
	7.15 Photoelastic Coatings
		7.15.1 Introduction
		7.15.2 Transfer of Stresses From Body to Coating
		7.15.3 Determination of Stresses
		7.15.4 Reinforcing Effect
		7.15.5 Photoelastic Strain Gages
	Further Readings
8 Interferometry
	8.1 Introduction
	8.2 Interferometers
	8.3 Analysis of Interferometers
		8.3.1 Introduction
		8.3.2 The Mach–Zehnder Interferometer
		8.3.3 The Michelson Interferometer
		8.3.4 The Fizeau-Type Interferometer
		8.3.5 Other Interferometers
		8.3.6 A Generic Analysis of Interferometers
	Further Readings
9 Holography
	9.1 Introduction
	9.2 Recording and Reconstruction Processes
	9.3 Holographic Interferometry
		9.3.1 Introduction
		9.3.2 Real-Time Holographic Interferometry
		9.3.3 Double-Exposure Holographic Interferometry
		9.3.4 Sensitivity Vector
	9.4 Holographic Photoelasticity
		9.4.1 Introduction
		9.4.2 Isochromatic-Isopachic Patterns
		9.4.3 Generic Interpretation
	Further Readings
10 Optical Fiber Strain Sensors
	10.1 Introduction
	10.2 Optical Fibers
		10.2.1 Introduction
		10.2.2 Structure
		10.2.3 Principle of Operation
		10.2.4 Applications
		10.2.5 Advantages and Disadvantages
	10.3 Fiber Optic Sensors (FOS)
		10.3.1 Architecture of a FOS
		10.3.2 Classification of FOSs
		10.3.3 Interferometric FOSs
		10.3.4 Fiber Bragg Grating Sensors (FBGSs)
		10.3.5 Multiplexing
		10.3.6 Advantages and Disadvantages of FOSs
		10.3.7 Applications of FOSs
	Further Readings
11 Speckle Methods
	11.1 Introduction
	11.2 The Speckle Effect
	11.3 Speckle Photography
		11.3.1 Introduction
		11.3.2 Point-by-Point Interrogation of the Specklegram
		11.3.3 Spatial Filtering of the Specklegram
	11.4 Speckle Interferometry
	11.5 Shearography
	11.6 Electronic Speckle Pattern Interferometry (ESPI)
	Further Readings
12 Digital Image Correlation (DIC)
	12.1 Introduction
	12.2 Steps of DIC
	12.3 Speckle Patterning
	12.4 Image Digitization
	12.5 Intensity Interpolation
	12.6 Image Correlation—Displacement Measurement
	12.7 2-D DIC
	12.8 3-D DIC
	12.9 Volumetric Digital Image Correlation (V-DIC)
	Further Readings
13 Thermoelastic Stress Analysis (TSA)
	13.1 Introduction
	13.2 Thermoelastic Law
	13.3 Infrared Detectors
	13.4 Adiabaticity
	13.5 Specimen Preparation
	13.6 Calibration
	13.7 Stress Separation
	13.8 Applications
	Further Readings
14 Indentation Testing
	14.1 Introduction
	14.2 Contact Mechanics
	14.3 Macro-indentation Testing
		14.3.1 Brinell Test
		14.3.2 Meyer Test
		14.3.3 Vickers Test
		14.3.4 Rockwell Test
	14.4 Micro-indentation Testing
		14.4.1 Vickers Test
		14.4.2 Knoop Test
	14.5 Nanoindentation Testing
		14.5.1 Introduction
		14.5.2 The Elastic Contact Method
		14.5.3 Nanoindentation for Measuring Fracture Toughness
	Further Readings
15 Nondestructive Testing (NDT)
	15.1 Introduction
	15.2 Dye Penetrant Inspection (DPI)
		15.2.1 Principle
		15.2.2 Application
		15.2.3 Advantages and Disadvantages
	15.3 Magnetic Particles Inspection (MPI)
		15.3.1 Principle
		15.3.2 Advantages and Disadvantages
	15.4 Eddy Currents Inspection (ECI)
		15.4.1 Principle
		15.4.2 Advantages and Disadvantages
	15.5 X-ray Diffraction (XRD)
		15.5.1 Introduction
		15.5.2 X-rays
		15.5.3 X-ray Diffraction
		15.5.4 Measurement of Strain
		15.5.5 Instrumentation
	15.6 Ultrasonic Testing (UT)
		15.6.1 Introduction
		15.6.2 Operation
		15.6.3 Advantages and Disadvantages
	15.7 Acoustic Emission Testing (AET)
		15.7.1 Introduction
		15.7.2 Acoustic Emission Testing
		15.7.3 Advantages and Disadvantages
	Further Readings
16 Residual Stresses—The Hole-Drilling Method
	16.1 Introduction
	16.2 Hole-Drilling Method
	16.3 Uniaxial Residual Stresses
	16.4 Biaxial Residual Stresses
	16.5 Variation of Residual Stresses Through the Thickness
	16.6 Nondestructive Methods for Measuring Residual Stresses
	Further Readings
Index