Research On Forming Characteristics Of Bimetallic Composite Tubes Under Impact Hydraulic Load

Tube Hydroforming technology based on lightweight structure features has been rapidly developed in recent years.Hollow parts formed by applying this technology generally have the advantages of lightweight,high strength,and good surface quality,and are currently being gradually promoted to parts design and manufacturing in the aerospace and automotive fields.However,this technology has suffered from inefficiencies and high equipment costs in industrial productions.Liquid Impact Forming combines traditional Tube Hydroforming technology and stamping forming technology to achieve rapid pressure rise in the pipe through stamping,eliminating the complicated high-pressure liquid supply system in traditional Tube Hydroforming technology.This technology also improves the forming efficiency,and has considerable application prospect and research significance.The research on the forming characteristics of bimetal composite tubes based on Liquid Impact Forming is an important prerequisite for in-depth research and popularization of this technology.Therefore,the following research is carried out on bimetal composite tubes based on Liquid Impact Forming:1.Analysis of the law of internal pressure formation in tubes under liquid impact load.According to the forming characteristics of Liquid Impact Forming,a numerical simulation analysis method of bimetal composite tubes based on Liquid Impact Forming with ANSYS Workbench is proposed.The numerical simulation process of pressure formation in bimetal composite tubes based on Liquid Impact Forming is introduced in detail.The influence of load parameters on the formation of internal pressure during bimetal composite tube forming is analyzed and summarized.2.Analysis of tube forming law under liquid impact load.Based on the obtained internal pressure during the forming process of the tube,a numerical simulation study of the Liquid Impact Forming process of bimetal composite tubes based on DYNAFORM was carried out,and the characteristic parameters of the tube under different loading conditions were obtained.The effects of different loading conditions on tube bulging height,fillet radius and wall thickness distribution were analyzed.The differences in tube bulging parameters under conventional forming conditions,with pressure holding conditions and with preforming conditions were compared.3.Analysis of hydraulic bulging limit of bimetal composite tubes.Based on the analysis of forming limit diagrams of the bimetal composite tube under Liquid Impact Forming,the forming status of the tube under different mold cavities and with or without holding pressure and preforming conditions is obtained.Specific analysis of the influence of different load parameters on the tube’s bulging limit is carried out,reasonable and effective forming parameter interval of the bimetal composite tube under the liquid impact environment is obtained.4.Optimization of Liquid Impact Forming process parameters based on Response Surface Method.Based on the Response Surface Method and finite element simulation,the wall thickness variance,bulging height and fillet radius were selected as optimization targets,and the mold side length,mold clamping speed and initial internal pressure were used as optimization parameters.A response surface model is established for the optimization targets and parameters.The objective function is optimized to obtain the optimal load parameter matching relationship,the final optimization results were determined,and the reliability of the response surface optimization results was verified by numerical simulations,which proved the effectiveness of the response surface model for the optimization of process parameters of bimetal composite tubes under a liquid impact environment.5.Experimental research on Liquid Impact Forming of bimetal composite tubes.The Liquid Impact Forming experiment system is introduced.Some representative load parameters were selected for the Liquid Impact Forming experiment.The results were compared with the numerical simulation results.By measuring the wall thickness distribution,bulging height and fillet radius of the formed tubes,the reliability of the research on the forming rule and forming characteristics of the bimetal composite tube under the liquid impact environment was verified.In this paper,analysis of the forming law of the internal pressure,the tube and bulging limit of bimetal composite tubes under liquid impact load were studied,the forming rule and characteristics of the tube were verified by Liquid Impact Forming experiment,it lays a foundation for the follow-up research of Liquid Impact Forming with bimetal composite tubes.