Measurements of velocity and attenuation of leaky waves using an ultrasonic array

Department of Physics, University of Windsor, 401 Sunset Avenue, Windsor, Ont., Canada N9B 3P4.
Ultrasonics (Impact Factor: 1.94). 03/2006; 44(2):182-7. DOI: 10.1016/j.ultras.2005.10.005
Source: PubMed


A new method of measuring velocity and attenuation of leaky surface waves is presented. A single focused transmitting transducer and linear receiving array in a pitch-catch arrangement are used in the proposed system. The spatial distribution of the acoustic field in the leaky wave is recorded by the array, and the parameters of the leaky wave can be obtained by processing the output waveforms. In comparison with existing material characterization systems, the mechanical scanning of the transducers is not used any more, and the measurement time is only limited by the time of the wave propagation and speed of the electronic data acquisition system.

10 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: An ultrasonic method of leaky surface acoustic waves measurement employing focused transducer and linear array mounted in a pitch-catch arrangement is considered. We present the wave theory of the system and demonstrate that the spatio-temporal spectrum of the output data set can be expressed as a product of the reflectance function of the liquid-specimen interface and overall transfer function of the system. By processing data in the spectral domain, it is possible to obtain parameters of dispersive waves. Using the wave model, it was shown that the angular resolution of the system increases with increasing of the number of the elements of the array and depends on the tilt angle of the array. Also, the problem of spatio-temporal spectrum aliasing was considered, and the maximal value of the pitch of the array was estimated at a given tilt angle of the array and directivity of the transmitting and receiving transducers. The results of the theoretical consideration were confirmed by the test experiments carried out in the 20 MHz frequency range
    No preview · Article · Jan 2006 · Proceedings of the IEEE Ultrasonics Symposium
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Rayleigh waves have been used to measure anisotropy in metal alloys using a transient Rayleigh pulse and an eight-element electromagnetic acoustic transducer array. The array spacing determined sensor separation, so that velocity measurements were made independent of the source-to-detector distance. Elimination of this distance, which would normally lead to systematic errors, has resulted in a measurement system capable of measuring velocities in metal to an uncertainty of 0.1%. As an example, variations in the Rayleigh velocity have characterized the anisotropy in rolled bars of aluminum.
    Full-text · Article · Sep 2006 · Applied Physics Letters
  • [Show abstract] [Hide abstract]
    ABSTRACT: We suggest a new method for determining the longitudinal and transverse acoustic wave velocities and sample thicknesses, which is based on the measurement and analysis of pulsed echo signals by an array of ultrasonic transducers. Analytical expressions relating the delay of signals detected by the array and the values of parameters to be determined are obtained within the framework of a ray model of the measuring system. Measurements on a reference sample have been performed. The values of ultrasonic wave velocities and sample thickness obtained using the proposed technique agree with the results of measurements using independent methods.
    No preview · Article · Nov 2009 · Technical Physics Letters
Show more