Research On The Vibration Force Transfer Performance Of Granular Media Under The Curve Path

Solid Granules Medium Forming Technology(SGMF)is a new technology for tube embryo forming,which uses particles instead of rigid punch.The process has the characteristics of no pollution,reusable medium,easy sealing and low cost.In the forming process,the material can be deformed under the most favorable conditions by controlling the pressure distribution due to the non-uniform pressure distribution of the granular medium.It can improve the forming limit and give full play to the forming properties of materials.The fluidity of granular media will determine the complexity of the formed parts.Good fluidity is more conducive to forming parts with small local characteristics.In order to improve the plasticity of metals and the fluidity of granular media,applying ultrasonic vibration to the forming process of granular media can improve the force transfer effect of granular media and the forming performance of parts.In this paper,the force transfer performance of granular media under different load transfer paths under vibration conditions is studied,which provides basic data for the pressure distribution law of high pressure forming process in granular media of pipe fittings.(1)Friction tests between particle medium and metal plate and between particles and particles under ultrasonic vibration were designed.The effects of vibration and pressure on friction coefficient between particle medium and metal plate and between particles and particles were discussed.(2)The force transfer performance of granular medium along straight wall tube(straight path)under vibration and non-vibration conditions is studied.The relationship between bottom pressure and punch pressure is obtained.The difference of bottom force transfer between two application methods is compared.Based on the discrete element method,the force chain evolution process,porosity and coordination number changes in the interior of particles were discussed.(3)The force transfer experiment of granular medium under curve path was designed,and the effects of amplitude,particle loading height and particle size on the force transfer performance of the curve were discussed.Based on the discrete elementmethod(DEM),the variation of porosity and coordination number on the transfer path of the strong chain is obtained.The experimental results are verified by using Dem element in Abaqus software and the coupling method of finite element and discrete element to simulate the side wall of the test device.