Study On The Law Of Liquid Impact Forming Of Double Thin-walled Tubes

In the field of modern manufacturing industry,materials with lightweight structure,low cost,low energy consumption and better comprehensive performance are the mainstream trend of future development.However,at present,the composite forming of double thin-walled tubes must rely on expensive liquid supply system,which results in complex forming,low efficiency and high cost and hinders its development.In order to solve this problem,this paper introduces an advanced forming method— "liquid impact forming method for double thin-walled tube".This method combines stamping technology on the basis of hydraulic pressure,which makes the inner tube filled with liquid and sealed plastic deformed by external radial clamping force,so that the inner tube is closely adhered to the outer tube.Because this method does not need the liquid supply system,it further realizes the production mode of high efficiency and low cost,it has good prospects for development.In order to study the liquid impact forming of double thin-walled tubes.This paper is based on theoretical analysis,the forming mechanism and forming law of liquid impact forming of double thin-walled tubes are analyzed comprehensively by means of joint verification of finite element simulation and test.Specific research contents are as follows:(1)Study on hydraulic pressure formation mechanism of liquid impact forming of double thin-walled tubes.Firstly,the forming principle of liquid impact forming of double thin-walled tubes is introduced.Then,the mathematical model between hydraulic pressure and volume change is obtained by theoretical analysis.Finally,the influence of different die cavity cross-section length and gap between inner and outer tubes on the hydraulic pressure produced by the liquid impact forming of double thin-walled tubes and its variation law are analyzed.(2)Hydraulic pressure research on liquid impact forming of double thin-walled tubes based on ANSYS WORKBENCH.Firstly,according to the forming method of liquid impact forming,the finite element simulation method of impact hydroforming is proposed.Then the analysis process of ANSYS WORKBENCH is introduced in detail.Finally,the influence of different initial parameters on the hydraulic pressure produced by impact hydroforming of double thin-walled tubes is analyzed and its variation law is summarized.(3)Research on Numerical Simulation of double thin-walled tube forming based on DYNAFORM.Firstly,the operation method and research purpose of DYNAFORM finite element software are introduced in detail.Then,DYNAFORM finite element software is used to analyze the influence of forming parameters such as axial feeding distance and impact velocity on the wall thickness distribution and filling properties of double thin-walled tubes joints.Finally,the forming rules are summarized and the optimum parameters are obtained.(4)Experimental study on liquid impact bulging of double thin-walled tubes.Firstly,the simple device of liquid impact bulging for double thin-walled tubes is introduced in detail.Then,the liquid impact bulging test of double thin-walled tube was carried out at the speed of 30mm/s.Finally,the experimental results are compared with the results of relevant parameters obtained by finite element simulation,and the error is analyzed,which further proves the feasibility of the liquid impact bulging method for double thin-walled tubes.Through theoretical analysis,numerical simulation and experimental verification of the forming mechanism and law of double thin-walled tubes by liquid impact forming,good research results have been obtained,which provides theoretical and practical basis for the application and popularization of double thin-walled tubes forming technology.