Design Of Key Mechanism And Simulation Of Process Optimization For Pipe Spatial Free Bending

With characteristics and advantages such as light weight,high specific strength,corrosion resistance and good processing and forming performance,metal pipes are called industrial"blood vessels",which are widely used in aerospace,nuclear industry,petrochemical industry,automotive pipelines,people’s livelihood and other fields.To achieve good overall structural performance,these industries typically require a series of processing methods to bend the pipes into a certain curved shape.Due to the limitations of traditional pipe bending techniques,free bending forming technology has become a research hotspot in the field of materials processing.This technology can control the attitude of the bending die in real time by computer design software to realize the control of free bending of the pipe.It has significant technical advantages in manufacturing continuous-variable-curved complex space components,and compared to traditional bending forming technology,which has lower forming cost,higher efficiency,and higher precision.Therefore,the space free bending forming technology has important research value and significance in the industrial application field.In this paper,the aluminum alloy pipe 6061 with 20 mm outer diameter and 1.5 mm wall thickness is taken as the object of study.Based on the triaxial free bending forming principle of the pipe,the bending forming mechanism and stress situation of the pipe are analyzed.The finite element simulation method is adopted to study and analyze the influence of key process parameters on the forming quality of the pipe,and the free bending forming process is optimized to obtain reasonable process parameter values.Then,the structurure design and development of the space free bending forming device are carried out.The main research contents are as follows:(1)This study analyzed the mechanism and process of free bending forming,described the stress situation and stress-strain distribution in the elastic and plastic stages of the tube bending process,and analyzed the variation law of the neutral layer and wall thickness during the bending process.(2)Establishing a finite element simulation constitutive model for aluminum alloy tube 6061,conducting fundamental mechanical experiments on aluminum alloy tube 6061,and comparing the simulation results with the experimental results to verify the validity of the simulation constitutive model.(3)Based on the three-axis free bending mechanism of tube bending,a finite element simulation analysis model was constructed to study the influence of key process parameters on the bending forming quality and precision of the tube,including the displacement of the bending die,the fillet radius at the contact between the bending die and the tube,the distance between the guide mechanism and the bending die,the gap between the tube and the bending die,the friction coefficient,and the feeding speed of the tube.(4)Based on the results of finite element simulation analysis,the pipe free bending forming device are designed and built by optimizing the values of the process parameters related to free bending forming.(5)Based on the constructed free bending forming equipment,the bending characteristics of the tube are extracted and analyzed through reverse recognition technology,and the reverse forming algorithm and software operating system are established.