Influences Of Size Parameters On The Bending Quality Of Metal Thin-walled Flat Elliptical Tube

Due to the special hollow structure,the pipe is used in industry,agriculture,military,construction and many fields of people’s daily life.Metal pipe bending is a plastic forming method for manufacturing tubular parts from metal pipes,which is an important part of metal plastic processing and advanced manufacturing technology,and is also one of the most challenging research hotspots in the field of metal plastic processing.However,so far,people’s research on the bending forming mechanism and forming technology of metal special-shaped pipe fittings is far from enough,so as to hinder the development of digital bending forming technology of such pipe fittings,so this technology is used It is of great significance to conduct in-depth exploration and research.In this thesis,the stress-strain state of metal thin-walled flat elliptical pipe fittings in the process of bending forming is analyzed in detail,and the stress-strain relationship between different positions and the theoretical position of the strain neutral layer of such pipe fittings in different positions during the bending process is derived.The stress-strain distribution of the top plate,bottom plate and circular arc side plate of the pipe fittings in different processes of bending in the tangential,radial and width directions was analyzed,and the different stages of the pipe fittings in the bending forming process were summarized Law of deformation.Secondly,the method of control variables was used to study the bending forming and springback process of four Q235 steel thin-walled flat elliptical pipe fittings with different cross-sectional size parameters,and the cross-sectional size parameters of the pipe were analyzed The influence and influence of the forming quality of bent pipe fittings.The analysis shows that the aspect ratio and bending radius of pipe section are the main factors affecting the forming quality of this kind of pipe bend,and the rebound angle of the pipe bending part is basically linear with its bending radius.Third,a test platform for metal thin-walled flat elliptical pipe fittings is established for bending,and a simple test mold is designed to meet the test requirements.The winding and forming test of Q235 steel thin-walled flat elliptical pipe fittings was carried out by using pipes with different wall thickness,aspect ratio and different bending speeds,and the theoretical analysis results of the forming quality of the elbow fittings were compared and characterized.The numerical simulation results and experimental results can be seen that they are basically consistent,and the error is below 15%,which verifies the reliability of the conclusions obtained by the previous numerical simulation research.