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 (SAFE) 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.

Ultrasonic Guided Waves in Solid Media

The paper provides a state of the art review of guided wave based structural health monitoring (SHM). First, the fundamental concepts of guided wave propagation and its implementation for SHM is explained. Following sections present the different modeling schemes adopted, developments in the area of transducers for generation, and sensing of wave, signal processing and imaging technique, statistical and machine learning schemes for feature extraction. Next, a section is presented on the recent advancements in nonlinear guided wave for SHM. This is followed by section on Rayleigh and SH waves. Next is a section on real-life implementation of guided wave for industrial problems. The paper, though briefly talks about the early development for completeness,. is primarily focussed on the recent progress made in the last decade. The paper ends by discussing and highlighting the future directions and open areas of research in guided wave based SHM.

https://iopscience.iop.org/article/10.1088/0964-1726/25/5/053001/pdf

Guided wave based structural health monitoring: A review

Ultrasonic guided wave inspection is expanding rapidly to many different areas of manufacturing and in-service inspection. The purpose of this paper is to provide a vision of ultrasonic guided wave inspection potential aswe move forward into the new millennium. An increased understanding of the basic physics and wave mechanics associated with guided wave inspection has led to an increase in practical nondestructive evaluation and inspection problems. Some fundamental concepts and a number of different applications that are currently being considered will be presented in the paper along with a brief description of the sensor and software technology that will make ultrasonic guided wave inspection commonplace in the next century.

A Baseline and Vision of Ultrasonic Guided Wave Inspection Potential

Guided wave dispersion curves for a bar with an arbitrary cross-section, a rod and rail example

A quantitative study of the reflection of the T(0,1) mode from defects in pipes in the frequency range 10-300 kHz has been carried out, finite element predictions being validated by experiments on selected cases. Both cracklike defects with zero axial extent and notches with varying axial extents have been considered. The results show that the reflection coefficient from axisymmetric cracks increases monotonically with depth at all frequencies and increases with frequency at any given depth. In the frequency range of interest there is no mode conversion at axisymmetric defects. With nonaxisymmetric cracks, the reflection coefficient is a roughly linear function of the circumferential extent of the defect at relatively high frequencies, the reflection coefficient at low circumferential extents falling below the linear prediction at lower frequencies. With nonaxisymmetric defects, mode conversion to the F(1,2) mode is generally seen, and at lower frequencies the F(1,3) mode is also produced. The depth and circumferential extent are the parameters controlling the reflection from cracks; when notches having finite axial extent, rather than cracks, are considered, interference between the reflections from the start and the end of the notch causes a periodic variation of the reflection coefficient as a function of the axial extent of the notch. The results have been explained in terms of the wave-number-defect size product, ka. Low frequency scattering behavior is seen when ka 1.

The reflection of the fundamental torsional mode from cracks and notches in pipes

Guided waves by axisymmetric and non-axisymmetric surface loading on hollow cylinders

Dispersion diagrams for longitudinal modes and several flexural modes are given. A partial loading oblique incidence technique was introduced for non-axisymmetric guided wave generation. Acoustic fields for partially loaded generation of guided waves were obtained along a sample Inconel steam generator tube surface. The axial field and the circumferential fields were non uniform. Even though the acoustic field was much more complicated than in the case of axisymmetric modes, the study of non-axisymmetric mode cannot be avoided; excitation of a single symmetric mode is often difficult due to limited access and transducer efficiency and there is also mode conversion after scattering from defects. For 100% inspection coverage of tubing and piping, three dimensional tuning (distance, frequency, and incident angle tuning), was employed. A single combination of incident angle, position, and frequency may miss defects in “blind spots”. However, complete inspection coverage of a whole cross sectional area over a certain distance of tubing was successfully demonstrated through a multi crack detection experiment by using the three dimensional tuning concepts. Also, the use of non-axisymmetric guided waves for a large distance inspection capability was successfully demonstrated.

Guided Wave Tuning Principles for Defect Detection in Tubing

Great progress is being made on the use of axisymmetric uhrasonie guided waves in tubing for defect detection, c1assification and sizing. Benefits of excellent penetration and sensitivity to certain defects are possible. However, ultrasonic guided wave propagation and reflection in tubing is still not completely understood. For more comprehensive knowledge of ultrasonic guided waves in tubing, a study on non-axisymmetric modes cannot be avoided. A number of non-axisymmetric modes close to the axisymmetric modes on a dispersion diagram often makes it difficult to generate a single axisymmetric mode in tubing. Also, non-axisymmetric reflections occur due to non-axisymmetric defects, even for axisymmetric impingement. The purpose of this study is to explore the use of non-axisymmetric ultrasonic guided waves for both faster and simpler inspection as weil as defect sizing analysis. As a result, it is hoped to optimize detection and screening via distance, incident angle, and frequency tuning.

Non-axisymmetric guided wa ves for tubing inspection

Great progress is being made on the use of axisymmetric ultrasonic guided waves in tubing for defect detection, classification and sizing. Benefits of excellent penetration and sensitivity to certain defects are possible. However, ultrasonic guided wave propagation and reflection in tubing is still not completely understood. For more comprehensive knowledge of ultrasonic guided waves in tubing, a study on non-axisymmetric modes cannot be avoided. A number of non-axisymmetric modes close to the axisymmetric modes on a dispersion diagram often makes it difficult to generate a single axisymmetric mode in tubing. Also, non-axisymmetric reflections occur due to non-axisymmetric defects, even for axisymmetric impingement. The purpose of this study is to explore the use of non-axisymmetric ultrasonic guided waves for both faster and simpler inspection as well as defect sizing analysis. As a result, it is hoped to optimize detection and screening via distance, incident angle, and frequency tuning.

https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=4039&context=qnde

Hyeon Jae Shin

Papers

Guided waves by axisymmetric and non-axisymmetric surface loading on hollow cylinders

Guided Wave Tuning Principles for Defect Detection in Tubing

Non-axisymmetric guided wa ves for tubing inspection

Non-Axisymmetric Guided Waves for Tubing Inspection