A novel co-optimization design method for piezoelectric ultrasonic transducer simultaneously considering the mechanical resonant frequency and mechanical quality factor requirements

Abstract The mechanical quality factor (MQF) is one of the most important performance parameters for sandwich-type piezoelectric ultrasonic transducer (PUT) used in ultrasonic machining, and it determines both the energy efficiency and 3 dB bandwidth of the transducer. In the traditional design method for the PUTs, the primary focus has been on achieving the target mechanical resonant frequency (MRF), while the MQF has critically relied on empirical knowledge and post-fabrication testing. To address this limitation, this study developed a novel MRF-MQF co-optimization design method for sandwich-type PUTs where the frequency equations and MQF calculation model were systematically established and then incorporated to determine the geometric parameters of the transducer. To validate the effectiveness and reliability of the proposed method, a prototype of the newly designed transducer was fabricated and then compared with a reference transducer designed using the conventional MRF-only method. Experimental results demonstrate that the newly designed transducer successfully satisfies the MRF requirement while simultaneously meeting both the MQF and bandwidth specifications. These results confirm that the proposed method is effective and reliable, and can be used as a general method for designing PUTs requiring simultaneous satisfaction of both MRF and MQF specifications.