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The authors present a model predicting the influence of various design parameters (geometrical dimensions, metal thickness, or groove depth) on the resonant frequency of surface transverse wave (STW) resonators. The model is based on the near-stopband approximation and the formalism of cascaded transfer matrices. Results are obtained in the case of a three-grating configuration (mirror-cavity-mirror) for both grooved and metal strip gratings. Based on simple analytical expressions, a design procedure is used, and the influence of various parameters is demonstrated and compared to already published experimental data. Experimental results obtained on metal strip quartz STW resonators are presented and discussed. >

An electromagnetic-acoustic transducer (EMAT) of novel design is used to excite and detect only those resonant modes of a cylinder that have a specific, integral number of nodes on the circumference. Because the nodal pattern is fixed and the coupling between the cylinder and transducer is weak, the resonances have very well defined frequencies which allow applications that include measurements of accurate shear wave velocities in commercial alloys, case depth in hardened steel shafts and axial stress in solid cylinders

The objective of the present work was to gain a deeper understanding of the vibration behavior of piezoelectric composite materials composed of PZT rods arranged in a periodic square lattice in a polymer matrix. Electrical admittance measurements and lalet probe dilatometry of the dynamic displacement on the composite surface were used to investigate t he vibration pattern of resonant modes. The effect of temperature on the electromechanical properties of the composite has also been studied as a function of frequency. The implication of these results for the design optimization of ultrasonic transducers are discussed.