Abstract
The dynamic response of microstructures including resonant frequency(KHz~MHz) and output displacement(nm~μm) is very similar to the ultrasonic transducers. Hence, this research intends to utilize the pulsed broadband ultrasonic transducer for the dynamic testing of microstructures. The performance of the bulk acoustic wave (BAW) hammer produced by broadband ultrasonic transducer will be designed and analyzed using the PIEZOCAD and ANSYS commercial software. And the micro cantilevers are the verification sample of the proposed method. Firstly, A BAW hammer proposed to determine the out-of-plane dynamic response of microstructures using pulsed single element broad bandwidth ultrasonic transducers. Therefore, the dynamic response of microstructures including resonant frequencies, mode shape and modal damping can be determined in one pulsed excitation. Secondly, the performance of the BAW hammer can be improved using the 1-3 composite ultrasonic transducers. Finally, the dual-mode ultrasonic array transducer is proposed to determine the in-plane and out-of-plane dynamic response of microstructures. The results reveal that experiments agree with the analysis and simulation. For one direction excitation, the 1-3 composite transducer is a good BAW hammer. On the other hand, the dual-mode ultrasonic array transducers can provide two-axial actuation. Since the proposed method and apparatus are very simple, and easy to implement, and also applicable to other microstructures, the approach has the potential to do the on-line testing for batch production.