Research On Springback And Process Of Numerical Controlled Bending Of Marine Tubes

In order to save the ship internal space,it is usually necessary to rationally distribute the pipe fittings in the cabin.The bending angle changes due to the springback,this not only affects the smooth installation of the pipe,but also causes the pipe to bear additional load at the joint.In severe cases,the connection will be broken.The non-margin bending process can effectively shorten the bending cycle and improve the utilization rate of the pipe,Therefore,the two aspects of springback and non-margin bending process are of great significance for the current shipbuilding.This paper takes the most commonly 20# pipe material as the research object,and gradually develops it according to the research plan,Through the combination of theoretical analysis and pratical experiments on CNC pipe bending machine,some progress has been made in the issue of tube bending springback and non-margin bending,including the following aspects:Analyzed the stress and strain of the cross-section of the bending section of the pipe,and the three processes of elastic deformation,elastic-plastic deformation and plastic deformation were studied.Considering the pure bending analysis of the tube by the power function hardening model before we establish the calculation model of the springback angle,the influence of the tube itself's parameters including mechanical properties,wall thickness,outer diameter,bending angle and relative bending radius on the bending springback of tube bending is analyzed.Established dynamic bending simulation process of pipe fittings through finite element analysis platform Dynaform,and carried out the orthogonal test design of the technological parameters affecting the springback,analyzed the change law of the average rebound angle of pipe fittings with process parameters,and then analyzed the significance of each process parameter affecting springback by variance analysis,the springback angle prediction equation was established according to the significant process parameters affecting springback,and finally verified.Study the process of pipe fittings with non-margin material and compare them with traditional techniques,and introduce three methods for calculating the blanking length,according to the length of neutral layer in bending section,the calculation model of the expansion length of the bending section is established.Finally,the specific steps of the pipe non-margin bending process are analyzed.