Results 211 to 220 of about 99,487 (264)
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Air-coupled Lamb wave tomography
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1997An entirely air-coupled inspection system using a pair of micromachined silicon capacitance transducers has been used to image defects in thin plates of different materials (0.7 mm to 2.22 mm thick) using air-coupled Lamb wave tomography. A filtered back projection algorithm was used in a form of difference tomography to reconstruct images of defects ...
W, Wright +3 more
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Internal Antisymmetric Lamb Waves
Акустический журнал, 2023A class of antisymmetric solutions of Lamb wave equations with zero strains and stresses on the surface, so-called internal Lamb waves, is studied. Two types of such solutions are found: the first corresponds to the Lamé phase velocity; the second, to phase velocities exceeding the velocity of the expansion wave in an unbounded medium.
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LAMB WAVES IN A POROELASTIC PLATE
Journal of Computational Acoustics, 2013In this paper we consider the propagation of Lamb waves in a poroelastic plate containing a linear crack, the special case where the surface of the plate is unloaded, by employing the Wiener-Hopf technique. The problem we solve here is a mathematically interesting toy problem. Physically speaking the more reasonable problem would be to consider there
Gilbert, Robert P. +2 more
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Long-Wave Asymptotics of Lamb Waves
Mechanics of Solids, 2017The six-dimensional complex formalism is used to obtain equations for determining long-wave asymptotics of symmetric fundamental modes of Lamb waves in an anisotropic layer. Analytic expressions are obtained for long-wave asymptotics of phase velocities of Lamb waves propagating in an isotropic layer.
R. V. Goldstein, S. V. Kuznetsov
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Journal of Applied Mathematics and Mechanics, 2009
The author presents results of an analysis of the velocity and the polarization of acoustic Lamb waves propagating in the directions of elastic symmetry of one- and two-layer anisotropic media at small vanishing frequencies (soliton-like waves). The method of fundamental matrices is used for the construction of a solution.
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The author presents results of an analysis of the velocity and the polarization of acoustic Lamb waves propagating in the directions of elastic symmetry of one- and two-layer anisotropic media at small vanishing frequencies (soliton-like waves). The method of fundamental matrices is used for the construction of a solution.
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Generalized Lamb-wave multisensor
IEEE 1988 Ultrasonics Symposium Proceedings., 2003Integrated-circuit fabrication techniques were used to make a versatile silicon-based sensor that uses elastic wave propagation in a plate that is thin compared with the wavelength. In-plane tension raises the velocity of the lowest antisymmetric flexural wave (474 m/s) above that predicted for a pure Lamb wave (422 m/s).
S.W. Wenzel, B.A. Martin, R.M. White
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Ultrasonic Lamb wave tomography
Inverse Problems, 2002The ultrasonic Lamb wave tomography is considered in the frame of the pressing nondestructive evaluation (NDE) technology need. The work focuses on tomographic reconstruction to produce quantitative maps that can be easily interpreted by technicians or fed directly into structural integrity and lifetime prediction codes.
Leonard, Kevin R. +2 more
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Efficient laser generation of Lamb waves
Optics Letters, 2014We report about the efficient generation of Lamb waves for nondestructive testing (NDT) of carbon fiber reinforced plastics (CFRP) with spatially formed laser beams. Therefore we describe the successful introduction of a liquid crystal on silicon (LCoS)-based spatial light modulator (SLM) to create predetermined spatial laser light distributions for a ...
Philipp, Huke +4 more
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Time-frequency representations of Lamb waves
The Journal of the Acoustical Society of America, 2001The objective of this study is to establish the effectiveness of four different time-frequency representations (TFRs)—the reassigned spectrogram, the reassigned scalogram, the smoothed Wigner–Ville distribution, and the Hilbert spectrum—by comparing their ability to resolve the dispersion relationships for Lamb waves generated and detected with optical
M, Niethammer +3 more
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Localization of notches with Lamb waves
The Journal of the Acoustical Society of America, 2003A time–frequency representation (TFR) is used to analyze the interaction of a multimode and dispersive Lamb wave with a notch, and then serves as the basis for a correlation technique to locate the notch. The experimental procedure uses a laser source and a dual-probe laser interferometer to generate and detect Lamb waves in a notched plate.
Rüdiger, Benz +3 more
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