Force-transmitting of granular medium under ultrasonic vibration: Experiments and simulation

Abstract

For the lightweight alloy tube which is hard to deform with conventional techniques, Ultrasonic vibration granular medium forming (UGMF) technology was proposed, combining solid granular medium forming with ultrasonic vibration plastic forming technology. To investigate the force-transmitting law of granular medium in the forming process of UGMF, and study the force-transmitting characteristics of granules medium under ultrasonic vibration, achieved the control of pressure distribution in the inner surface of the tube to improve the forming performance of tube. The curve path force-transmitting experiment under ultrasonic vibration was designed, the distribution law of lateral pressure has been obtained, and in combination with Janssen stress distribution Based on the Janssen stress distribution, the expression of the pressure function of the curve path force-transmitting was derived. At the same time, PFC2D and ABAQUS software were used to establish the discrete element method (DEM) model and the finite element method (FEM)-DEM coupling model, the microscopic and macroscopic curve path force-transmitting analysis of the ultrasonic vibration. The influence of ultrasonic vibration on curve path force-transmitting was investigated. The results show that the application of ultrasonic vibration increases the force-transmitting performance of the granules, and the force-transmitting efficiency is twice that of the non-vibration condition. Based on the experimental results, the accuracy of the expression was verified. From the microscopic point of view, it is found that the application of ultrasonic vibration makes the granular force chain thicker and the force-transmitting efficiency increases. From the macroscopic point of view, it is found that with the increase of transverse distance, the highest point of the lateral wall of the curve moves downward.