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
    Proceedings of the IEEE Ultrasonics Symposium 01/2006; 1:148-151. DOI:10.1109/ULTSYM.2006.50
  • [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.
    Technical Physics Letters 11/2009; 35(11):1029-1031. DOI:10.1134/S1063785009110170 · 0.57 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An ultrasonic system with a linear array for characterization of a layered specimen placed in immersion liquid parallel to the aperture of the array is considered. To estimate the longitudinal and transverse wave velocities as well as the thickness and density of the specimen, it is proposed to decompose the spatio-temporal data recorded by the array in a spectrum of plane pulse waves. Based on fitting the developed wave model of the system to the experimental data, it is shown that the relative delays and amplitudes of the spectral responses can be used for the estimation of the velocities and thickness of the layer and its density. The distortions of the plane wave spectrum caused by the spatial discretization of the array data are considered. It is proposed to suppress these distortions using individual interpolating processing of the received pulses separated in the spatio-temporal domain. The developed technique is experimentally verified on a fused quartz plate evaluated with a 17-MHz linear array. The relative reproducibility of the estimation is found to be 0.11% in the longitudinal wave velocity and thickness of the plate, and 0.5% and 5% in the transverse wave velocity and the density, respectively.
    IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 07/2013; 60(7):1435-1445. DOI:10.1109/TUFFC.2013.2715 · 1.51 Impact Factor
Show more