Flexible-bending Process Of Profiles And Tubes And Its Numerical Simulation

Profiles and tubes have been used in manufacturing automobiles,planes and ships so widely,that the forming quality of bent profiles and tubes can affect the using of many products directly.The bending forming methods have been one of the hot topics in material forming field.In the traditional ways of bending forming of profiles and tubes with different radii,different dies have to be used,which leads to higher cost and longer production period.Conventional methods,such as rotary-draw bending and push bending,are even are unable to use in forming bent profiles and tubes with continuous varying radii.Therefore,it's important and valuable to research novel bending method.Flexible-bending is a new bending forming method used in bending of profiles and tubes,the main advantages of which are reduced forming cost,shortened production cycle and flexibility of bending forming.In the process of flexible-bending,flexible and shifting die is used instead of conventional fixed bending die.Bent profiles and tubes with different radii are formed by adjusting the location and tipping angle of bending die.So a set of flexible-bending equipment can forming bent profiles and tubes of different curvatures,and achieve forming bent profiles and tubes with continuous varying radii.Information technologies and computer functions blossom rapidly,facilitating increasingly application of computer simulation technology,which results in widely use of simulation in products development.Finite element analysis software has been used in simulating the flexible-bending process of profiles and tubes,so as to research the stress and strain distribution of bending profiles and tubes,the curvatures varying trends,predicting and eliminating side bending defects and optimizing technological parameters.In this paper,numerical simulation was used to research the influence of location and offset of bending die in curvatures of bent profiles and tubes.The defect elimination method by shifting bending die in reverse direction of side bending and the practice of forming bent profiles and tubes of continuous varying radii by shifting bending die continuously were studied.The main contents and conclusions are summarized as follows:1.Research on the principle of flexible-bendingThe principle and process of flexible-bending of profiles and tubes were studied.The differences between flexible-bending method and conventional bending method were analyzed.The feasibility and advantages of flexible-bending method were introduced.2.Establishment of finite element model of flexible-bending of profiles and tubesBased on the principle of flexible-bending,the finite element model of flexible-bending of profiles and tubes were established respectively.The parameters of finite model were defined on the basis of bending experiments such as element unit,element grid,boundary conditions and contact and friction condition,which laid the foundation of simulation research of flexible-bending process.3.Research on flexible-bending of profiles and elimination method of side bending defectFlexible-bending process of profiles was simulated to explore the curvature varying trend of bent profile while adjusting parameters of bending die.The mechanism of occurring of side bending defect in bent profiles was analyzed and the relevant elimination method of the defect was research,which was also verified in experiments.4.Research on flexible-bending of tubes and minimum bending coefficientFlexible-bending process of tubes were simulated to explore the influence of bending die parameters on curvatures of bent tubes.Bending program of minimum bending coefficient tube on the basis of the varying trend of bending curvature was analyzed,which was verified by simulations and experiments.5.Confirmation and achievement of program of flexible-bending of profiles and tubes of continuous varying radiiThe program of flexible-bending of profiles and tubes was explored,including the setting of parameters in flexible-bending equipment.The feasibility of bending profiles and tubes of continuous varying radii and of several bends were explored by means of numerical simulations,which were verified by relevant experiments.