Research On Hydroforming Of Variable-diameter Tube Tube Based On Fuzzy Control

With the development of the society,fuel consumption and exhaust emissions have received more and more attention from people.Reducing the quality of car bodies and parts,and realizing the lightening of automobiles have become a hot topic in the current automobile manufacturing discussions.Compared with traditional processes such as forging and stamping,the hydroforming process improves production efficiency and reduces production costs.In addition,most of the hydro-formed parts are integrally formed,which not only reduces the quality,but also improves the strength and rigidity.Tube hydroforming technology has advantages in the manufacture of automotive parts with spatially shaped cross-section features such as rear suspensions,various types of connecting tubes for automobiles,connecting fittings,torsion beams and so on.which promotes the rapid development of tube hydroforming technology in various fields of manufacturing.The research object of this paper is the T-shaped tube and the cantilever trailing arm of a certain vehicle model.First,the hydroforming research on the typical T-shaped tube is carried out.The material parameters are obtained by material stretching.The equipment carried out hydroforming experiment,compared the simulation and experimental results,verified the accuracy of the finite element numerical calculation and model establishment,and analyzed the influence of different parameters on the forming quality.Afterwards,the suspension trailing arm material was stretched to obtain Material parameters,carry out simulation analysis of the three forming stages of suspension trailing arm prebending,preforming and hydroforming,and analyze the results.Then based on the combination of fuzzy control and finite element simulation,the research on the hydroforming law of the T-shaped tube is carried out,and the optimal parameter combination is used to carry out the T-shaped tube experiment,which verifies the correctness of the fuzzy control optimization.Based on this,the hydraulic optimization simulation of the suspension longitudinal arm was carried out by using the fuzzy control method,and the influence law of key factors on the forming quality of the suspension trailing arm was studied.Finally,the large-scale hydraulic forming equipment was used to test the suspension trailing arm prototype.During the experiment,the loading path of the prebent tube and the preforming experiment and The traditional simulation results are consistent,the hydroforming experiment is based on the loading path obtained by fuzzy control optimization,and three-stage experimental samples are obtained,and the wall thickness is measured at the typical cross-section of each sample.To verify the reliability of the experimental and simulation results.The research results show that the T-shaped tube loading path obtained based on the optimization of fuzzy control has a faster pressure increase in the early period and a slower axial feed increase;a slower pressure increase in the middle and later stages and a faster axial feed increase.The bulging height and wall thickness uniformity of the forming result are improved.The change trend of the pressure loading path in the suspension trailing arm based on fuzzy control optimization is basically the same as the step loading path,but it is a smooth curve,and the medium-term holding pressure time is shortened,and the later-stage holding pressure time is increased.The combination of parameters is used to conduct the hydroforming experiment of the suspension trailing arm,and a well-shaped sample of the suspension trailing arm can be obtained.In this paper,the hydroforming simulation analysis of the T-shaped tube and the subframe suspension trailing arm based on fuzzy control is completed,and the hydrostatic forming experiment of the suspension trailing arm is completed using the loading path optimized by the fuzzy control,and the main parameters of the suspension are studied.It provides a reference for the practical application of hydroforming technology of automobile suspension trailing arm.