Research On Springback Simulation Of Aluminum Alloy Profile Bending Forming

Due to its high specific strength,light weight and excellent formability,aluminum alloy profiles are increasingly used in the manufacture of car bodies for high-speed train sets.In actual production,effective control of bending springback and precise forming of aluminum alloy profiles is still an urgent problem in the field of material processing.In this paper,the rebound phenomenon in the bending and forming of the opening structure profile of the rail train is investigated by analytical calculation and numerical simulation methods respectively.The bending springback of the profile was predicted using an analytical calculation method.Optimization of bending process parameters by numerical simulation method.For the forming of complex curvature profiles,a drawing and pressing compound forming process is designed.The main research content and achievements of this article are as follows:(1)The commonly used 6005 A aluminum alloy profiles were selected and tensile tests were conducted to obtain the material mechanical property parameters;Select 3 typical profile parts.The finite element models of tension bending,compression bending and tension-compression bending were established,respectively.(2)The force analysis of the bending loading process and unloading rebound process of the profile was carried out.The strain expressions after bending loading,after unloading and after reverse elastic loading of the profile are derived.The geometric constraint equations for the bending resilience of the profile plane are established.And derive the formula for calculating the springback radius of profile drawing and bending forming.The derived rebound calculation equation is applied to the rebound calculation for each of the three profiles bent and formed.The calculated results were also compared and analyzed with the numerical simulation results.The results show that in tension bending and compression bending with small curvature deformation.The error between the analytical rebound calculation results and the numerical simulation results is small.The minimum error ranges are 1.15% to 2.26% and 1.44% to 1.83%,respectively.(3)The influence law of different process parameters on the drawing and forming of aluminum alloy profiles was analyzed by numerical simulation.The results show that the profile springback decreases with the increase of pre-stretch,complementary stretch,wrap stretch and bending and die angle.Increasing with increasing friction coefficient;The section distortion after profile forming basically increases with the increase of pre-stretching amount,complementary stretching amount and cladding stretching amount.The simulated results of profile rebound for several different cladding tensile amounts are investigated in comparison with the analytical calculations.The relative deviation of the post-bounce radius values predicted by the analytical calculation from the numerical simulation was found to decrease from 1.83% to 1.01% when the amount of cladding stretch was increased from 0% to 5%.Numerical simulation of aluminum alloy profile bending and forming.The influence law of process parameters such as bending radius,friction coefficient and bending center angle on the rebound of profile bending and forming was studied.The simulation results show that the greater the bending radius and friction coefficient the greater the rebound and the greater the bending center angle the smaller the rebound in the same position of the profile.(4)For complex curvature profile parts,the pull-press composite forming method is proposed.Numerical simulations were carried out to study three tension-compression composite forming schemes of drawing-bending followed by segmental bending,bending followed by complementary stretching and drawing-bending with simultaneous loading.The laws of profile drawing and compression compound forming and the effect of different loading methods on rebound were analyzed.It was found that: In forming partially large curvature profiles,the forming scheme of drawing bending followed by segmental bending can effectively improve the problem of low forming accuracy at the curvature transition position of the profile under drawing bending loading;The use of bending and post-tensioning forming solution can reduce the forming errors caused by springback in bending forming to a certain extent.In the forming of the edge-unbending combination of bending profiles,among the three drawing-compression composite forming solutions,the smallest springback is achieved by first drawing and then segmental bending,with a maximum springback error of only 1.435mm;Maximum rebound error of 2.824 mm for simultaneous tension-bending-compression bending loading;The use of bending followed by complementary stretching forming solution can also reduce the springback under bending forming,but the overall forming accuracy is not high,the maximum forming error is 9.052 mm.