TITLE

Time-Delay Periodic Linear Array: A unidirectional guided wave transducer for ultrasonic NDT applications

AUTHOR(S)
Zhu, Wenhao; Chahbaz, A.; Brassard, M.
PUB. DATE
May 2000
SOURCE
AIP Conference Proceedings;2000, Vol. 509 Issue 1, p1057
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Due to their improved mode selectivity and small geometrical size, linear-array transducers have recently found increasing application in guided wave NDT of metallic structures. In this paper, simple and flexible Time-Delay Periodic Linear Array (TDPLA) designs are described and used for guided wave inspection of different metallic structures. Using wave interference effect, unidirectional guided wave excitation and reception are achieved. Several TDPLA patterns are experimentally tested to produce different guided modes. The unidirectional TDPLA transducer has been applied to detect defects (cracks and notches) in metallic structures in a pulse-echo scheme. Experimental results from several specimens are also compared to those obtained from tests using conventional wedge transducers. Compared to bi-directional linear arrays (such as combs and interdigital arrays), which emit guided waves at both sides of arrays, time-delay periodic arrays generate efficiently guided modes with high wave energy concentration at one side and avoid the unnecessary wave emission at the other side. © 2000 American Institute of Physics.
ACCESSION #
6029292

 

Related Articles

  • Air-coupled acoustic imaging with zero-group-velocity Lamb modes. Holland, Stephen D.; Chimenti, D.E. // Applied Physics Letters;9/29/2003, Vol. 83 Issue 13, p2704 

    A Lamb wave resonance has been found that allows unusually efficient transmission of airborne sound waves through plates. This occurs at the zero-group-velocity point at the frequency minimum of the first-order symmetric (S[sub 1]) Lamb mode. At this frequency, plane waves with a range of...

  • Reflection and scattering of the S[sub 0] Lamb mode from 3-D circular defects in plates. Diligent, O.; Lowe, M. J. S.; Cawley, P. // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p231 

    A second study of the interaction of Lamb waves with a circular defect is presented. The Lamb wave mode chosen was the So mode in the low frequency-thickness regime. A three dimensional Finite Element mesh was generated, representing an area of the plate with a circular part-depth hole (33% or...

  • Lamb wave scattering by defects: A hybrid boundary element-finite element formulation. Galan, J. M.; Abascal, R. // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p211 

    A hybrid Boundary Element (FE) — Finite Element (BE) Formulation is applied to study Lamb wave scattering by defects in homogeneous isotropic plates. A BE model of the neighborhood of the defect is combined with a semi-analytical FE non-reflecting boundary condition which accurately...

  • Rapid transmission coefficient reconstruction and material property estimation in plates. Fei, Dong; Chimenti, D. E.; Teles, Sorin V. // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p1400 

    Rapid reconstruction of the transmission coefficient (TC) of a fluid-loaded plate across large frequency and phase-match angular ranges is achieved by performing a synthetic aperture scan with a pair of highly focused transducers in a transmission arrangement. The mode cutoffs are easily mapped...

  • Analysis of plate wave motions excited by a point load using a wavelet transform. Jeong, Hyunjo // AIP Conference Proceedings;2001, Vol. 557 Issue 1, p119 

    Plate wave motions excited by a point surface load on a finite plate were analyzed using the Mindlin plate theory. Both the flexural and extensional wave motions were considered. To validate the Mindlin plate solutions for finite plates, plate waves in a 3 mm thick aluminum plate were generated...

  • An Effective Generation of Lamb Waves in a Thin Plate Using Laser Line Array Illumination and Their Propagation Characteristics. Jang, T. S.; Lee, J. J.; Lee, S. S. // AIP Conference Proceedings;2003, Vol. 657 Issue 1, p311 

    Symmetric and antisymmetric Lamb modes are excited in low-frequency-thickness regime by illuminating a thin plate with an array of Q-switched Nd:YAG laser-generated line sources. The propagation of laser-generated Lamb waves is detected by measuring the out-of-plane displacements in a...

  • Numerical and experimental deviation of monochromatic Lamb wave beam for anisotropic multilayered media. Baly, Ste´phane; Potel, Catherine; de Belleval, Jean-Franc¸ois; Lowe, Mike // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p270 

    The interaction of an incident monochromatic bounded beam with an anisotropic multilayered plate immersed in an external fluid has been modelled, using the decomposition method into monochromatic plane waves and the transfer matrix method, in a 3D configuration. The subject of this paper is the...

  • Propagation of Lamb waves in anisotropic and absorbing plates: Theoretical derivation and experiments. Neau, G.; Lowe, M. J. S.; Deschamps, M. // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p1062 

    The aim of this work is to gain a better understanding of the propagation of Lamb waves in anisotropic and absorbing plates. A study of the energy velocities and attenuations of Lamb waves in such media is presented here. In the first part, propagation in principal directions has been studied....

  • Laser Generated Rayleigh and Lamb waves. Edwards, C.; Stratoudaki, T.; Dixon, S.; Palmer, S. B. // AIP Conference Proceedings;2002, Vol. 615 Issue 1, p284 

    Laser Generated Rayleigh and Lamb waves are studied in Aluminum samples. Broadband Rayleigh waves are generated using a TEM[sub 00] mode Nd:YAG laser. In the thermoelastic regime the Rayleigh wave impulse response from a laser line source is a negative going (inward displacement) delta function....

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics