Guided Lamb waves for identification of damage in composite structures: A review

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Art of electronics

http://ieeexplore.ieee.org/iel5/5/31047/01444179.pdf

Fundamentals of acoustics

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

Surface integrity in material removal processes: Recent advances

Nonlinear Lamb waves for the detection of material nonlinearity

This research combines laser ultrasonic techniques with the two-dimensional Fourier transform (2D-FFT) to characterize adhesive bond properties. The experimental procedure consists of measuring a series of equally spaced, transient Lamb waves in specimens consisting of aluminum plates joined with an adhesive bond. The frequency spectrum (dispersion curves) for each specimen are obtained by operating on these transient waveforms with the 2D-FFT. This study quantifies the effect of bond stiffness on the dispersion curves of two different bonded specimens (a single aluminum plate with an adhesive transfer tape attached to one side, and two aluminum plates joined with the same adhesive tape) and four adhesive bond conditions (un-aged, and three different aging temperatures and times). The proposed procedure consists of first determining the frequency spectrum of the Lamb waves that propagate in each of the two bonded specimens (plus a single plate); these measurements provide the dispersion curves for each specimen in their un-aged state. Degradation causes changes in the stiffness of an adhesive bond, which causes changes in the dispersion curves of the aged specimens. Experimentally measured dispersion curves are used to quantitatively track changes in the bonded specimens, as a function of age. Finally, these experimental results are interpreted in terms of an analytical model that replaces the adhesive bond layer with a linear spring boundary condition.

Characterization of adhesive bond properties using Lamb waves

Rapid Evaluation of Alkali-silica Reactivity of Aggregates Using a Nonlinear Resonance Spectroscopy Technique

Coda wave interferometry (CWI) is a nondestructive evaluation technique for monitoring wave velocity changes in a strongly heterogeneous medium as demonstrated in previous seismic and acoustic experiments. The multiple-scattering effect in such a medium promotes the rapid formation of a diffuse field, and waves can travel much longer than the direct path, and thus are more sensitive to small changes occurring in the medium. This research applies the CWI technique in conjunction with acoustoelastic measurements to characterize two different types of damage in concrete: damage due to thermal shock and dynamic cyclic loading. The diffuse ultrasonic signals are taken at different levels of compressive stress and then relative velocity changes are extracted using the CWI technique. The relative velocity change (or the material nonlinearity) increases considerably with increasing damage level in most samples for both types of damage. The feasibility and sensitivity of this CWI-based technique in characterizing damage in cement-based materials are demonstrated.

Damage detection in concrete using coda wave interferometry

Shot-peening is widely used in the aerospace industry to enhance the resistance of structural components to fatigue damage and stress corrosion by putting the outside layer of a component under an initial, residual compressive stress. The ability to measure these near-surface residual stresses is useful from a quality control and certification perspective, and can help predict the fatigue life of shot-peened components. This paper presents experimental results to examine the feasibility of measuring near-surface residual stresses using nonlinear Rayleigh surface waves. Experiments are conducted on aluminum alloy (AA 7075) samples shot-peened at different peening intensities and thus with different levels of residual stresses. The surface roughness of these samples is also measured. The nonlinear ultrasonic results show a large increase in the acoustic nonlinearity parameter, indicating the potential of nonlinear ultrasonics for the in situ measurement of near-surface residual stresses. The effects of surface roughness and the driving frequency on the measured acoustic nonlinearity parameter are briefly discussed. Finally, a preliminary model is used to interpret some experimental results. Future work to evaluate the separate contributions of cold work, residual stress and surface roughness to the total measured nonlinearity is also discussed.

Laurence J. Jacobs

Papers

Nonlinear Lamb waves for the detection of material nonlinearity

Characterization of adhesive bond properties using Lamb waves

Rapid Evaluation of Alkali-silica Reactivity of Aggregates Using a Nonlinear Resonance Spectroscopy Technique

Damage detection in concrete using coda wave interferometry

Experimental study of nonlinear Rayleigh wave propagation in shot-peened aluminum plates—Feasibility of measuring residual stress