Author
Bernard Hosten
Bio: Bernard Hosten is an academic researcher from University of Bordeaux. The author has contributed to research in topics: Lamb waves & Ultrasonic sensor. The author has an hindex of 29, co-authored 73 publications receiving 2537 citations.
Papers published on a yearly basis
Papers
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TL;DR: The interaction of the low-order antisymmetric (a0) and symmetric (s0) Lamb waves with vertical cracks in aluminum plates is studied and these coefficients together with the through-thickness displacement fields are compared to those predicted using a finite element code widely used in the past for modeling Lamb mode diffraction problems.
Abstract: The interaction of the low-order antisymmetric (a0) and symmetric (s0) Lamb waves with vertical cracks in aluminum plates is studied. Two types of slots are considered: (a) internal crack symmetrical with respect to the middle plane of the plate and (b) opening crack. The modal decomposition method is used to predict the reflection and transmission coefficients and also the through-thickness displacement fields on both sides of slots of various heights. The model assumes strip plates and cracks, thus considering two-dimensional plane strain conditions. However, mode conversion (a0 into s0 and vice versa) that occurs for single opening cracks is considered. The energy balance is always calculated from the reflection and transmission coefficients, in order to check the validity of the results. These coefficients together with the through-thickness displacement fields are also compared to those predicted using a finite element code widely used in the past for modeling Lamb mode diffraction problems. Experiments are also made for measuring the reflection and transmission coefficients for incident a0 or s0 lamb modes on opening cracks, and compared to the numerical predictions.
165 citations
TL;DR: In this article, the authors developed a method for investigating some anisotropic media, such as composites, by the use of ultrasonic waves transmitted through a plate-shaped sample immersed in water.
Abstract: This article develops a method for investigating some anisotropic media, such as composites, by the use of ultrasonic waves transmitted through a plate‐shaped sample immersed in water. The discussion begins with Christoffel’s equations for plane linear anelastic waves under the assumptions that for small angles of incidence the wave modes are plane and inhomogeneous and that the anisotropy is representable by hexagonal symmetry. The water–sample interface is treated using the law of Snell–Descartes for nonabsorbing media and takes into account mode conversion and the generation of acoustic surface waves. The method produces viscoelastic constants and relative attenuation coefficients as a function of the angle of refraction. The experimental measurement apparatus is described and data are given for the 25‐layer unidirectional Gr/epoxy composite. Results are presented in terms of slowness, damping vector, and attenuation curves. The results are significant in that they demonstrate the anisotropy both for t...
157 citations
TL;DR: In this paper, an adaptation of the Thomson/Haskell method to introduce anisotropic attenuation into the formulation of the transfer matrix is presented, taking into account the heterogeneity of the generated modes at interfaces between absorbing media.
Abstract: This paper presents an adaptation of the well‐known Thomson/Haskell method to introduce anisotropic attenuation into the formulation of the transfer matrix. The expression for the transfer matrix of one elementary ply is modified to take into account the heterogeneity of the generated modes at interfaces between absorbing media. This heterogeneity depends on the direction of propagation and on the anisotropic attenuation of the ply. The transfer matrix of the stratified composite is derived classically from the multiplication of the elementary matrices and leads to the transfer function of the plate. The transmission and reflection coefficients of multilayered viscoelastic anisotropic composite materials can be computed, for any direction of propagation and for any stacking sequence, with a program that requires the viscoelastic characteristics of the ply. The method is tested with PEEK matrix/carbon fibers composites. The viscoelastic properties of the ply were previously measured with a unidirectional c...
123 citations
TL;DR: The propagation of Lamb-like waves in sandwich plates made of anisotropic and viscoelastic material layers is studied and the mode-coupling phenomenon is confirmed, and the potential of the air-couple system for developing single-sided, contactless, NDT applications of such structures is discussed.
Abstract: The propagation of Lamb-like waves in sandwich plates made of anisotropic and viscoelastic material layers is studied. A semi-analytical model is described and used for predicting the dispersion curves (phase velocity, energy velocity, and complex wave-number) and the through-thickness distribution fields (displacement, stress, and energy flow). Guided modes propagating along a test-sandwich plate are shown to be quite different than classical Lamb modes, because this structure does not have the mirror symmetry, contrary to most of composite material plates. Moreover, the viscoelastic material properties imply complex roots of the dispersion equation to be found that lead to connections between some of the dispersion curves, meaning that some of the modes get coupled together. Gradual variation from zero to nominal values of the imaginary parts of the viscoelastic moduli shows that the mode coupling depends on the level of material viscoelasticity, except for one particular case where this phenomenon exists whether the medium is viscoelastic or not. The model is used to quantify the sensitivity of both the dispersion curves and the through-thickness mode shapes to the level of material viscoelasticity, and to physically explain the mode-coupling phenomenon. Finite element software is also used to confirm results obtained for the purely elastic structure. Finally, experiments are made using ultrasonic, air-coupled transducers for generating and detecting guided modes in the test-sandwich structure. The mode-coupling phenomenon is then confirmed, and the potential of the air-coupled system for developing single-sided, contactless, NDT applications of such structures is discussed.
118 citations
TL;DR: In this article, an ultrasonic air-coupled C-scan technique and X-ray radiography were used to detect impact damage in thin carbon fiber/epoxy composite plates.
117 citations
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TL;DR: A comprehensive review on the state of the art of Lamb wave-based damage identification approaches for composite structures, addressing the advances and achievements in these techniques in the past decades, is provided in this paper.
1,350 citations
TL;DR: This paper presents a review of the main developments of the matrix techniques, and their use in response and modal models, with emphasis on ultrasonics applications.
Abstract: Research into ultrasonic NDE techniques for the inspection of multilayered structures relies strongly on the use of modeling tools which calculate dispersion curves and reflection and transmission spectra. These predictions are essential to enable the best inspection strategies to be identified and their sensitivities to be evaluated. General purpose multilayer modeling tools may be developed from a number of matrix formulations which have evolved in the latter half of this century and there is now a formidable number of publications on the subject. This paper presents a review of the main developments of the matrix techniques, and their use in response and modal models, with emphasis on ultrasonics applications. >
931 citations
Book•
11 Aug 2014
TL;DR: The semi-analytical finite element method (SAFE) has been used for guided wave modeling as discussed by the authors, which has been shown to be useful in the analysis and display of non-destructive testing.
Abstract: 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.
823 citations
TL;DR: In this paper, a variety of techniques used to obtain the mechanical properties of materials at high rates of strain (⩾10 s−1) are summarised, including dropweight machines, split Hopkinson pressure bars, Taylor impact and shock loading by plate impact.
683 citations
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