Research On Bend Forming Of Rectangular Section Tube For High Strength Steel

Rectangular section tube for high strength steel has the advantages of lightweight and high strength, which can save a large amount of metal whileguaranteeing intensity and has broad application prospect in automobile and otherindustrial fields. However, cracking, wrinkling and springback are common defectsin bend forming, which have seriously hindered the application and development oftube bending technologies. Research on bend forming of rectangular section tube forhigh strength steel can not only enrich the modern plastic processing technology butalso has realistic guiding significance and reference for the application of highstrength bending parts in automobile manufacturing and other industrial fields.The state of stress and strain is analysed and their expression is derived basedon the basic theory of elastic-plastic deformation of metallic material. The locationof strain neutral layer is calculated. The function relationship between tangentialstrain of tube surface and bending radius as well as aspect ratio is established.A finite element model of rectangular section tube for high strength steel inbend forming and springback is built by ABAQUS to get the stress and strain indifferent bending process. Based on control variate method, the influence laws offour bending parameters (thickness, bending radius, fillet radius and aspect ratio) onbend forming and springback is studied, it shows that bending radius and aspectratio have great influence on tube bending and springback.The bending mould and mandril is designed and the test platform is established.The experiments of bend forming in different thickness, bending radius and aspectratio are carried out. The datum of strain and springback angle are compared withthe results of theoretical research and numerical research, whose average errors areabout13.92%and9.37%. It means the results of theoretical research and numericalresearch are accurate, the error causes are analyzed.