Horn Design and Simulation for Ultrasonic-Assisted Shear Extrusion Process

Abstract

Ultrasonic vibrations are high-frequency vibrations. Sliding friction occurs between two solid surfaces when they slide on each other. By applying ultrasonic vibrations to one of these two objects, the friction force between them could be reduced. This property has many applications in forming and machining processes. To produce and transmit ultrasonic vibrations to the target area, it is necessary to design an ultrasonic system including the generator, transducer, and concentrator. Concentrator (horn) is an important part of an ultrasonic system that its most important duty is to transmit ultrasonic vibrations and amplify their amplitude at its output. In this study, two aluminum concentrators with cylindrical-conical-cylindrical and cylindrical-exponential-cylindrical geometries were designed to transmit ultrasonic vibrations to the channel area in the simple shear extrusion process. Modal analysis was performed in Abaqus to select the best horn. The resonant frequency obtained from Abaqus software was used in three bending, torsional, and longitudinal modes for both horns. Since only the longitudinal vibration mode was in the generator resonant frequency range and a more suitable vibration amplitude was reported geometrically, it was applied in a simple shear extrusion process. Finally, the resonance frequency simulation results of 19.927 kHz for the cylindrical-exponential-cylindrical horn and the value of 21.381 kHz for the cylindrical-conical-cylindrical horn were reported. By comparison under the same design and simulation conditions, cylindrical-exponential-cylindrical horn performed better and provided more ideal adaptation to the generator resonant frequency.