Study On Loading Control Of Joint Swing Free Pipe Bending Process

Joint swing free pipe bending process is a new three-dimensional bending process.This process has high machining efficiency,good forming quality,and can achieve continuous bending with variable radius in any direction and at any angle.It has been widely used in aerospace,automobile manufacturing and other fields,but this technology is still in the basic research stage in China.In this paper,the loading control of joint swing free bending process is taken as the research object,aiming at studying the influence of loading control on forming capacity,forming quality and the mechanical structure design of loading system.The specific work content is as follows:Firstly,the elastoplastic mechanics theory of metal pipe bending forming and the constitutive relation model of forming material are studied,and the process parameters are analyzed according to the forming principle of joint swing free pipe bending process,and the corresponding theoretical formulas are deduced.Then,the loading motion of the joint swinging free bend process is analyzed.Aiming at the typical pipe fittings,a numerical analysis model for the forming process of joint swing free bending pipe is established,two loading modes are put forward,then analyzed from two aspects of theoretical analysis and numerical simulation,and the better loading mode is selected.The coordination relationship of loading speed is analyzed,and the corresponding values of the loading speed of the specific feasible domain are solved by numerical method,and the forming quality analysis under the speed coordination relation is carried out,and the loading speed range and matching relation are solved to meet the requirements of forming quality.Furthermore,the influence of the process loading on the forming capacity and quality is studied by using the finite element numerical simulation of the process.The function relationship between bending radius and loading offset,the function relationship between bending angle and feed time,and the minimum bending coefficient under the model are solved,and the influence degree of loading parameters on wall thickness thinning rate and ellipticity is studied based on orthogonal analysis and numerical simulation technology,and the influence of bending angle and bending pipe coefficient on rebound is analyzed.The formula of bending angle before and after the rebound coefficient of different bending pipes is also solved.Finally,the mechanical structure of the loading system of the free pipe bending device and the information flow of the control system are studied.Firstly,the overall conceptual design of the free pipe bending device is carried out,and the mechanical structure design and calculation of the loading system are carried out according to the main technical requirements and indexes,and the functional conceptual design,hardware composition design and information flow design of the loading control system are carried out.This paper takes the loading control of the joint swing free pipe bending process as the research object.According to the principle of the free pipe bending process,the elastic-plastic finite element numerical simulation is used to study the loading movement curve and the loading control law,providing a theoretical basis for the later research and development of the free pipe bending machine.