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Book Description

This book describes the theory and practice of the Hole-Drilling Method for measuring residual stresses in engineering components. Such measurements are important because residual stresses have a "hidden" character because they exist locked-in within a material, independent of any external load. These stresses are typically created during component manufacture, for example, during welding, casting, or forming. Because of their hidden nature, residual stresses are difficult to measure and consequently are often ignored. However, they directly add to loading stresses and can cause catastrophic failure if not properly included during engineering design. Thus, there is an urgent need to be able to identify and measure residual stresses conveniently and reliably.

The Hole-Drilling Method provides an adaptable and well-proven method for measuring residual stresses in a wide range of materials and component types. It is convenient to use and gives reliable results. Because of the hidden nature of residual stresses, the measurement method must necessarily be indirect, thus, additional care and conceptual understanding are necessary to achieve successful results. This book provides a practical introduction to the Hole-Drilling Method, starting from its historical roots and going on to focus on its modern practice. The various chapters describe the nature of residual stresses, the principle of hole-drilling measurements, procedures and guidance on how to make successful measurements, and effective mathematical procedures for stress computation and analysis. The book is intended for practitioners who need to make residual stress measurements either occasionally or routinely, for practicing engineers, for researchers, and for graduate engineering and science students.

Table of Contents

  1. Preface
  2. Nature and Source of Residual Stresses
    1. Introduction
    2. Origin of Residual Stresses
    3. Sources of Residual Stresses
      1. Bulk Component Misfit in Redundant Structures
      2. Non-Uniform Dimensional Variations due to Thermal Effects
      3. Non-Uniform Plastic Deformation
      4. Surface Machining
      5. Surface Treatments
      6. Chemical and Phase Change
    4. Types of Residual Stresses
      1. Residual Stress Type I
      2. Residual Stress Type II
      3. Residual Stress Type III
    5. Effects of Residual Stress
    6. Residual Stress Measurements
    7. Further Reading
  3. Relaxation Type Residual Stress Measurement Methods
    1. Introduction
    2. Relaxation Method Concept
    3. Excision Method
    4. Two-Groove Method
    5. Splitting Method
    6. Slitting (Crack Compliance) Method
    7. Ring-Core Method
    8. Hole-Drilling Method
    9. Deep-Hole Method
    10. Layer-Removal Method
    11. Contour Method
    12. Sectioning Method
    13. Impact of Modern Measurement Technologies
    14. Method Selection
    15. Further Reading (1/2)
    16. Further Reading (2/2)
  4. Hole-Drilling Method Concept and Development
    1. Introduction
    2. Concept
    3. Mathar's Foundational Work
    4. Hole Drilling
    5. Deformation Measurements
    6. Ring-Core Method
    7. Deep-Hole Drilling
    8. Residual Stress Computations
    9. Concluding Remarks
    10. Further Reading (1/2)
    11. Further Reading (2/2)
  5. Strain Gauge Technique: Method Description
    1. Strain Gauge Rosette Selection
    2. Specimen Preparation
    3. Gauge Installation
    4. Instrumentation and Electrical Connections
    5. Hole-Drilling Equipment
    6. Hole-Drilling Procedure
    7. Gauge Data
    8. Further Reading
  6. Stress Computations
    1. Introduction
    2. Uniform Residual Stresses
    3. Calibration Constants
    4. Stress Averaging
    5. Non-Uniform Residual Stresses
    6. Practical Determination of and
    7. Regularization
    8. Other Calculations
      1. Differential Strain and Average Stress Methods
      2. Power Series Method
      3. Specimen Thickness
      4. Hole Eccentricity Correction
      5. Plasticity Effects
      6. Orthotropic Materials
    9. Further Reading (1/2)
    10. Further Reading (2/2)
  7. Example Practical Procedures and Results
    1. Specimen Geometry and Strain Gauge Selection Details
    2. Practical Strain Gauge Rosette Installations
    3. Orientation of Type B Strain Gauge Rosettes
    4. Installation on Irregular Surfaces: Bond Thickness
    5. Non-Standard Gauges
    6. Residual Stress Example: Training Sample (Annealed Disc)
    7. Residual Stress Example: Aluminium Alloy Block
    8. Residual Stress Example: Machined, Forged Disc
    9. Residual Stress Example: Surface Process Samples
    10. Residual Stress Example: Thin, Shot-Peened Beam
    11. Concluding Remarks
    12. Further Reading
  8. Optical Techniques
    1. Introduction
    2. Holographic Interferometry
    3. Moiré Interferometry
    4. Electronic Speckle Pattern Interferometry (ESPI)
    5. Digital Image Correlation
    6. Computation of Uniform Residual Stresses (1/2)
    7. Computation of Uniform Residual Stresses (2/2)
    8. Computation of Non-Uniform Residual Stresses
    9. Residual Stress Computation Using Incremental Data
    10. Concluding Remarks
    11. Further Reading
  9. Authors' Biographies
  10. Index
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