Study on longitudinal-bending coupling in slotted cylindrical piezoelectric ultrasonic transducer

A longitudinal-bending coupled piezoelectric ultrasonic transducer (LBCP) is proposed to address the limitations of conventional sandwiched piezoelectric transducers, which predominantly exhibit unidirectional vibration modes. The LBCP transducer integrates a longitudinal sandwiched piezoelectric transducer with a slotted metal hollow cylinder, enabling synergistic longitudinal-bending coupled vibrations. Based on the theory of bending vibration and the equivalent circuit of the coupled vibration of the metallic tube, the electromechanical equivalent-circuit model is established to predict the coupled vibration characteristics and resonant frequencies. Finite element method simulations and impedance analysis experiments are employed to validate the theoretical predictions, demonstrating strong agreement between simulated and calculated resonant frequencies. The slotted configuration demonstrates strong longitudinal-bending coupling modes, offering a paradigm for advanced coupled-mode transducer design.