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Journal ArticleDOI

Lamb wave frequency–wavenumber analysis and decomposition

17 Feb 2014-Journal of Intelligent Material Systems and Structures (SAGE Publications)-Vol. 25, Iss: 9, pp 1107-1123
TL;DR: In this paper, the authors used Lamb wave detection for detection of thin-walled structures due to their long propagation capability and sensitivity to a variety of different types of damage types.
Abstract: Lamb waves have shown great potentials in damage detection of thin-walled structures due to their long propagation capability and sensitivity to a variety of damage types. However, their practical ...
Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors provide a state-of-the-art review of guided wave based structural health monitoring (SHM) and highlight the future directions and open areas of research in guided wave-based SHM.
Abstract: 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.

664 citations

Journal ArticleDOI
18 Jan 2019-Sensors
TL;DR: The characterization of PWAS materials shows that no significant change in the microstructure after exposure to high temperature and nuclear radiation, and the PWAS transducer can be used in harsh environments for structural health monitoring (SHM) applications.
Abstract: In this paper, some recent piezoelectric wafer active sensors (PWAS) progress achieved in our laboratory for active materials and smart structures (LAMSS) at the University of South Carolina: http: //www.me.sc.edu/research/lamss/ group is presented. First, the characterization of the PWAS materials shows that no significant change in the microstructure after exposure to high temperature and nuclear radiation, and the PWAS transducer can be used in harsh environments for structural health monitoring (SHM) applications. Next, PWAS active sensing of various damage types in aluminum and composite structures are explored. PWAS transducers can successfully detect the simulated crack and corrosion damage in aluminum plates through the wavefield analysis, and the simulated delamination damage in composite plates through the damage imaging method. Finally, the novel use of PWAS transducers as acoustic emission (AE) sensors for in situ AE detection during fatigue crack growth is presented. The time of arrival of AE signals at multiple PWAS transducers confirms that the AE signals are originating from the crack, and that the amplitude decay due to geometric spreading is observed.

125 citations

Journal ArticleDOI
TL;DR: An optimized physics-informed neural network trained to solve the problem of identifying and characterizing a surface breaking crack in a metal plate is introduced and shows a promising deep neural network model for ill-posed inverse problems.
Abstract: We introduce an optimized physics-informed neural network (PINN) trained to solve the problem of identifying and characterizing a surface breaking crack in a metal plate. PINNs are neural networks that can combine data and physics in the learning process by adding the residuals of a system of partial differential equations to the loss function. Our PINNs is supervised with realistic ultrasonic surface acoustic wave data acquired at a frequency of 5 MHz. The ultrasonic surface wave data is represented as a deformation on the top surface of a metal plate, measured by using the method of laser vibrometry. The PINN is physically informed by the acoustic wave equation and its convergence is sped up using adaptive activation functions. The adaptive activation function uses a trainable hyperparameter, which is optimized to achieve the best performance of the network. The adaptive activation function changes dynamically, involved in the optimization process. The usage of the adaptive activation function significantly improves the convergence, evidently observed in the current study. We use PINNs to estimate the speed of sound of the metal plate, which we do with an error of 1%, and then, by allowing the speed of sound to be space dependent, we identify and characterize the crack as the positions where the speed of sound has decreased. Our study also shows the effect of sub-sampling of the data on the sensitivity of sound speed estimates. More broadly, the resulting model shows a promising deep neural network model for ill-posed inverse problems.

125 citations


Cites methods from "Lamb wave frequency–wavenumber anal..."

  • ...In a related effort, frequency-wavenumber analysis was used to discriminate between bulk and surface wave modes scattered from a surface-breaking crack [12, 13]....

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Journal ArticleDOI
TL;DR: A parallel algorithm to model the nonlinear dynamic interactions between ultrasonic guided waves and fatigue cracks and the explicit contact formulation, the parallel algorithm, as well as the GPU-based implementation facilitate LISA's high computational efficiency over the conventional finite element method (FEM).

80 citations

Journal ArticleDOI
TL;DR: In this article, material damping is a critical parameter in selection of a particular wave mode for wave attenuation in composites, and it cannot be neglected in the selection of wave modes.
Abstract: Guided wave attenuation in composites due to material damping is strong, anisotropic, and cannot be neglected. Material damping is a critical parameter in selection of a particular wave mode for lo...

79 citations

References
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Book
01 Sep 2004
TL;DR: In this article, the theory of elasticity was introduced and basic formulas and concepts in complex variables in the theory and application of wave propagation were discussed. But the authors did not consider the effects of wave scattering on the wave propagation experiments.
Abstract: Preface 1. Introduction 2. Dispersion principles 3. Unbounded isotropic and anisotropic media 4. Reflection and refraction 5. Oblique incidence 6. Wave scattering 7. Surface and subsurface waves 8. Waves in plates 9. Interface waves 10. Layer on a half space 11. Waves in rods 12. Waves in hollow cylinders 13. Guided waves in multiple layers 14. Source influence 15. Horizontal shear 16. Waves in an anisotropic layer 17. Elastic constant determination 18. Waves in viscoelastic media 19. Stress influence 20. Boundary element methods Bibliography Appendices A. Ultrasonic nondestructive testing principles, analysis and display technology B. Basic formulas and concepts in the theory of elasticity C. Basic formulas in complex variables D. Schlieren imaging and dynamic photoelasticity E. Key wave propagation experiments Index.

2,570 citations


"Lamb wave frequency–wavenumber anal..." refers background in this paper

  • ...Once the frequency– wavenumber (f–k) relations are known, group velocity dispersion curves of different modes can also be calculated (Rose, 1999)....

    [...]

  • ...…modes Ai (i = 0, 1, .) in terms of the surface particle motion with regard to the mid-plane, which are described in Rayleigh–Lamb equations (Rose, 1999) Symmetricmodes : tan (qh) tan (ph) = 4k 2qp (k2 q2)2 ð1Þ Antisymmetricmodes : tan (qh) tan (ph) = (k 2 q2)2 4k2qp ð2Þ where p2 = v2 c2L…...

    [...]

  • ...The fundamentals of Lamb waves can be found in many textbooks, such as Graff (1975), Rose (1999), and Viktorov (1967)....

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  • ...From the Rayleigh–Lamb equations, the relationship between frequency f and wavenumber k can be solved numerically (Rose, 1999)....

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  • ...which are described in Rayleigh–Lamb equations (Rose, 1999)...

    [...]

Book
01 Feb 1993
TL;DR: This chapter discusses how signals in Space and Time and apertures and Arrays affect Array Processing and the role that symbols play in this processing.
Abstract: 1. Introduction 2. Signals in Space and Time 3. Apertures and Arrays 4. Conventional Array Processing 5. Detection Theory 6. Estimation Theory 7. Adaptive Array Processing 8. Tracking Appendices References List of Symbols Index.

1,933 citations


"Lamb wave frequency–wavenumber anal..." refers background in this paper

  • ...straightforwardly extended to multidimensional signals such as the time–space wavefield data, which is in terms of the time variable t and the space vector x (Johnson and Dudgeon, 1993)....

    [...]

  • ...Accordingly, the multidimensional FT in equation (3) reduces to 2D FT, which can be expressed as (Johnson and Dudgeon, 1993) U ( f , kx)=F2D u(t, x)½ = ð‘ ‘ ð‘ ‘ u(t, x)e j(2pft kxx)dtdx ð6Þ The inverse 2D FT becomes u(t, x)=F 12D U ( f , kx)½ = 1 2p ð‘ ‘ ð‘ ‘ U ( f , kx)e j(2pft kxx)dfdkx ð7Þ F2D…...

    [...]

  • ...The concept of Fourier analysis is straightforwardly extended to multidimensional signals such as the time–space wavefield data, which is in terms of the time variable t and the space vector x (Johnson and Dudgeon, 1993)....

    [...]

  • ...Accordingly, the multidimensional FT in equation (3) becomes three-dimensional (3D) FT, which can be expressed as (Johnson and Dudgeon, 1993)...

    [...]

  • ...Accordingly, the multidimensional FT in equation (3) becomes three-dimensional (3D) FT, which can be expressed as (Johnson and Dudgeon, 1993) U ( f , kx, ky)=F3D u(t, x, y)½ = ð‘ ‘ ð‘ ‘ ð‘ ‘ u(t, x, y)e j(2pft kxx kyy)dtdxdy ð8Þ The inverse 3D FT becomes u(t, x, y)=F 13D U ( f , kx, ky) = 1 (2p)2…...

    [...]

BookDOI
01 Jan 1967

1,877 citations


"Lamb wave frequency–wavenumber anal..." refers background in this paper

  • ...The fundamentals of Lamb waves can be found in many textbooks, such as Graff (1975), Rose (1999), and Viktorov (1967)....

    [...]

Journal ArticleDOI
TL;DR: In this article, the authors considered the problem of two-dimensional wave propagation in a solid bounded by parallel planes, and proposed a simple solution to the problem, which has no bearing on the questions referred to in this paper.
Abstract: The theory of waves in an infinitely long cylindrical rod was discussed by Pochhammer in 1876 in a well-known paper The somewhat simpler problem of two-dimensional waves in a solid bounded by parallel planes was considered by Lord Rayleigh and by the present writer‡ in 1889 The main object in these various investigations was to verify, or to ascertain small corrections to, the ordinary theory of the vibrations of thin rods or plates, and the wave-length was accordingly assumed in the end to be great in comparison with the thickness It occurred to me some time ago that a further examination of the two-dimensional problem was desirable for more than one reason In the first place, the number of cases in which the various types of vibration of a solid, none of whose dimensions is regarded as small, have been studied is so restricted that any addition to it would have some degree of interest, if merely as a contribution to elastic theory Again, modern seismology has suggested various questions relating to waves and vibrations in an elastic stratum imagined as resting on matter of a different elasticity and density These questions naturally present great mathematical difficulties, and it seemed unpromising to attempt any further discussion of them unless the comparatively simple problem which forms the subject of this paper should be found to admit of a practical solution In itself it has, of course, no bearing on the questions referred to

1,413 citations


"Lamb wave frequency–wavenumber anal..." refers background in this paper

  • ...Lamb waves are a subset of guided waves that propagate between two parallel surfaces such as in shell and plate structures (Lamb, 1917)....

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  • ...Lamb wave propagation study setup Lamb wave dispersion curves Lamb waves are a subset of guided waves that propagate between two parallel surfaces such as in shell and plate structures (Lamb, 1917)....

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Book
05 Dec 2007
TL;DR: Structural Health Monitoring with Piezoelectric Wafer active sensors (PWAS) as mentioned in this paper is the first comprehensive textbook to provide background information, theoretical modeling, and experimental examples on the principal technologies involved in SHM.
Abstract: Structural Health Monitoring (SHM) is the interdisciplinary engineering field devoted to the monitoring and assessment of structural health and durability. SHM technology integrates remote sensing, smart materials, and computer based knowledge systems to allow engineers see how built up structures are performing over time. It is particularly useful for remotely monitoring large infrastructure systems, such as bridges and dams, and high profile mechanical systems such as aircraft, spacecraft, ships, offshore structures and pipelines where performance is critical but onsite monitoring is difficult or even impossible."Structural Health Monitoring with Piezoelectric Wafer Active Sensors" is the first comprehensive textbook to provide background information, theoretical modeling, and experimental examples on the principal technologies involved in SHM. This textbook can be used for both teaching and research. It not only provides students, engineers and other interested technical specialists with the foundational knowledge and necessary tools for understanding modern sensing materials and systems, but also shows them how to employ this knowledge in actual engineering situations.It addresses the problem of aging structures and explains how SHM can alleviate their situation and prolong their useful life. It provides a step by step presentation on how Piezoelectric Wafer Active Sensors (PWAS) are used to detect and quantify the presence of damage in structures. It presents the underlying theories (piezoelectricity, vibration, wave propagation, etc.) and experimental techniques (E/M impedance, PWAS phased arrays, etc.) to be employed in successful SHM applications. It provides an understanding of how to interpret sensor signal patterns such as various wave forms, including analytical techniques like Fast Fourier Transform, Short-time Fourier Transform and Wavelet Transform. It offers comprehensive teaching tools (worked examples, experiments, homework problems, and exercises) and an extensive online instructor manual containing lecture plans and homework solutions.

929 citations