Book contents
- Frontmatter
- Contents
- Nomenclature
- Preface
- Acknowledgments
- 1 Introduction
- 2 Dispersion Principles
- 3 Unbounded Isotropic and Anisotropic Media
- 4 Reflection and Refraction
- 5 Oblique Incidence
- 6 Waves in Plates
- 7 Surface and Subsurface Waves
- 8 Finite Element Method for Guided Wave Mechanics
- 9 The Semi-Analytical Finite Element Method
- 10 Guided Waves in Hollow Cylinders
- 11 Circumferential Guided Waves
- 12 Guided Waves in Layered Structures
- 13 Source Influence on Guided Wave Excitation
- 14 Horizontal Shear
- 15 Guided Waves in Anisotropic Media
- 16 Guided Wave Phased Arrays in Piping
- 17 Guided Waves in Viscoelastic Media
- 18 Ultrasonic Vibrations
- 19 Guided Wave Array Transducers
- 20 Introduction to Guided Wave Nonlinear Methods
- 21 Guided Wave Imaging Methods
- Appendix A Ultrasonic Nondestructive Testing Principles, Analysis, and Display Technology
- Appendix B Basic Formulas and Concepts in the Theory of Elasticity
- Appendix C Physically Based Signal Processing Concepts for Guided Waves
- Appendix D Guided Wave Mode and Frequency Selection Tips
- Index
- Plates
- References
19 - Guided Wave Array Transducers
Published online by Cambridge University Press: 05 July 2014
- Frontmatter
- Contents
- Nomenclature
- Preface
- Acknowledgments
- 1 Introduction
- 2 Dispersion Principles
- 3 Unbounded Isotropic and Anisotropic Media
- 4 Reflection and Refraction
- 5 Oblique Incidence
- 6 Waves in Plates
- 7 Surface and Subsurface Waves
- 8 Finite Element Method for Guided Wave Mechanics
- 9 The Semi-Analytical Finite Element Method
- 10 Guided Waves in Hollow Cylinders
- 11 Circumferential Guided Waves
- 12 Guided Waves in Layered Structures
- 13 Source Influence on Guided Wave Excitation
- 14 Horizontal Shear
- 15 Guided Waves in Anisotropic Media
- 16 Guided Wave Phased Arrays in Piping
- 17 Guided Waves in Viscoelastic Media
- 18 Ultrasonic Vibrations
- 19 Guided Wave Array Transducers
- 20 Introduction to Guided Wave Nonlinear Methods
- 21 Guided Wave Imaging Methods
- Appendix A Ultrasonic Nondestructive Testing Principles, Analysis, and Display Technology
- Appendix B Basic Formulas and Concepts in the Theory of Elasticity
- Appendix C Physically Based Signal Processing Concepts for Guided Waves
- Appendix D Guided Wave Mode and Frequency Selection Tips
- Index
- Plates
- References
Summary
Introduction
Multiple element array transducers are extremely useful and popular in today’s inspection environment. The first applications were to carry out electronic B and C scans opposed to earlier developed mechanical scans. This was followed by phasing of the elements in a bulk wave problem where beam steering and focusing were possible during the electronic scanning process. Today, array transducers are being used in guided wave inspection. Linear comb and annular array sensors are two possibilities. Beyond electronic scanning and focusing it is also now possible to select time delay profiles for guided wave mode and frequency selection to optimize sensitivity to certain defects and penetration power in special situations. Thus, time delays for mode selection and electronic scanning can be superimposed for rapid and efficient NDT and SHM. As a consequence, such items as the excitation spectrum and the mode excitability function will be studied along with phasing principles for linear combs and annular arrays.
To employ guided waves for nondestructive evaluation (NDE) or structural health monitoring (SHM) purposes, these waves must first be generated in the structure of interest. Accordingly, to fully reap the benefits guided waves can offer, such wave generation should be performed in a well-designed, highly controlled manner, which is only possible through deliberate transducer design. Proper guided wave mode control can provide distinct advantages in terms of sensitivity to particular defects, sensitivity to environmental variables, penetration power, and other factors in guided wave inspection. Additionally, the suppression of spurious modes and/or the excitation of a particularly nondispersive mode can greatly enhance the potential signal analysis of gathered data by simplifying the waveforms.
- Type
- Chapter
- Information
- Ultrasonic Guided Waves in Solid Media , pp. 359 - 377Publisher: Cambridge University PressPrint publication year: 2014