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

Abstract

In industrial applications, the highly stressed axial components are easily damaged by cyclic loads if their surfaces are not enhanced, since cracks and stress concentrations occur on the cylindrical components after turning. By the peening processes, the residual tensile stress can be removed and the surface hardness can be increased, thereby increasing the tool life. Compared to other peening processes, ultrasonic cavitation peening is a potential method to achieve surface processing of metal specimens and attracted much attention, since fewer polluting effluents are produced, with the exception of metal oxide powder that can be easily collected and recycled. Additionally, this method is cheap to perform and there are no thermal effects. In this project, we proposed a V-shaped traveling wave piezoelectric vibrating system for the ultrasonic cavitation peening to achieve an even performance on a cylindrical surface upon single treatment. The transfer matrix modeling and the cavitation field have already been investigated. In the investigations of the ultrasonic cavitation field, only the radial vibration in the inner surface of the ring sonotrode was considered and studied. However, the effects of the tangential vibration on the cavitation intensity and distribution as well as the mechanical properties of the workpiece surfaces are important to evaluate the performances of the proposed V-shaped transducer. In this paper, the numerical simulation of fluid–structure interaction (FSI) was investigated by first using the finite element method, considering liquid pressure, liquid flow velocity and vapor volume fraction. Then, the liquid flow velocity was measured using the color tracer method to validate the FSI results. Finally, the treatments for cylindrical workpieces using ultrasonic cavitation peening were conducted, and the performances of the treatments were evaluated by means of micro-hardness and surface roughness. The results show that the roughness of the cylindrical workpiece surfaces did not increase significantly, but micro hardness increased by as high as 54%.