Index of content:
Volume 105, Issue 3, March 1999
- TRANSDUCTION 
105(1999); http://dx.doi.org/10.1121/1.426717View Description Hide Description
The longitudinal–torsional compound transducer with slanting slots is studied. The compound transducer is composed of a sandwiched longitudinal ultrasonic transducer and a transmission cylinder with slanting slots. The equivalent circuit for the longitudinal–torsional vibrating system is derived. Based on the equivalent circuit, the input mechanical impedance and the resonance-frequency equation for the compound system are obtained. The effect of the slanting angle of the slanting slots, the position of the slanting slots, and the geometrical length of the slanting slots on the resonance frequency of the compound longitudinal–torsional system is analyzedtheoretically and experimentally. Experiments show that the measuredresonance frequencies are in good agreement with the predicted results.
Elastic contact problem of the piezoelectric material in the structure of a bolt-clamped Langevin-type transducer105(1999); http://dx.doi.org/10.1121/1.426704View Description Hide Description
Bolt-clamped Langevin-type transducers (BLTs) are widely used in various fields of industrial application of high-power ultrasonics. One of the most crucial points in designing a transducer of this type is estimation of the bearing stress imposed by clamping on the interface between the metal block and the piezoelectric element. This prestress, which compensates for low tensile strength of the piezoelectric materials used, must be larger than the dynamic vibratory stress at the interface between the components in high-amplitude operation. Precise estimation of it is virtually impossible, owing to an intricate elastic contact problem. However, with the use of the unique finite-element-analysis system developed by one of the authors, approximate solutions of the problem have been obtained. A BLT design based on the results of the prestress calculations is proposed. The results of its experimental verification have also been reported.