Theoretical modeling and experimental investigation of a V-shaped traveling wave piezoelectric transducer for ultrasonic cavitation Peening: Part A

Abstract

Ultrasonic cavitation peening is a surface enhancement technology that can increase surface hardness without obviously introducing a high surface roughness of the treatment surfaces. However, the most commonly used traditional transducers for ultrasonic cavitation peening are operated in the longitudinal mode and generate a standing wave in the working gap between a sonotrode end and a treated surface, causing a small cavitation treated area and low efficiency for treating the axis components. To achieve a high efficiency on the surfaces of axis components, a new V-shaped traveling wave transducer is proposed in this paper. Two Langevin transducers are employed to couple on the ring sonotrode, generating two third order in-plane bending vibrations with a spatial phase difference of 90° in the ring. Therefore, same elliptical vibrations are generated in all points on inner surface of the ring, resulting in a uniform cavitation effect around the axis component which is located in the center of the ring sonotrode. It is the first time to propose that cavitation bubbles are generated utilizing traveling waves. An analytical model is created utilizing the transfer matrix method for the vibrating system to describe the dynamic behavior and predict the acoustic field of the working area in the ring sonotrode. To validate the developed transfer matrix model, experimental investigations were conducted to measure the vibration characteristics of the proposed transducer and compared to the transfer matrix model calculation results. For further proving the feasibility of the cavitation peening, sonochemiluminescence was carried out to evaluate the distribution of cavitation bubbles in the working area. The results show that calculation results have a good agreement with the experimental results and a higher voltage and smaller working gap were beneficial for the ultrasonic cavitation treatment utilizing this novel transducer.