Numerical Simulation And Optimization Of Hydroforming Of Automotive Structural

Tube hydroforming technique is an advanced manufacturing technique as well asa main technique method for automobile lightweight. The principle of hydroformingis that the tube is forced into the die cavity and formed via inner pressing and axialapplication of force and feed. The process relates to many factors, such as die comer,friction between tube and die, tube dimension and material characteristics, thematching relationship between the pressure applied inside tube and the axial pressure,and in addition, for tube with branched pipe such as T-tube and Y-tube, the backpressure. The most important factor is the matching relationship between thehigh-pressure fluid pressure applied inside tube and the axial pressure, which affectsthe shape of cross section, the thickness distribution and final forming dimensiondirectly. As we know, in the process of tube hydroforming, the tube plasticdeformation is limited by forming defects such as buckling, crinkle and crack, so thematching relationship of processing parameters has an important effect on the formingresult. But the ideal values through the single factor method are not optimum sets, soit’s significant to optimize the matching relationship.In this paper, numerical simulation analysis is performed for a tee pipe throughFEM software DYNAFORM, and study the influence law of the results about thethree main process parameters inner pressure, the axial feeding speed and the backpressure on forming, and compared the influence of the forming quality with the singlelinear and bilinear loading paths of single factor. In this paper， load path parameteroptimization based on orthogonal test design theory, and the test with tee innerpressure．The results shows that the orthogonal test design is a kind of test designmethod with high efficiency and multifactor for optimum level combination，it canwell solve the problems which the parameters optimization of internal high-pressureforming process. Based on the application of optimization design in tee inner pressure, thehydroforming simulation analysis is performed on the rear suspension twist beam ofA-class car. According to the structure of the twist beams V special-shapedcross-section of complex deformation process characteristics, this paper puts forwardone kind stage with the pressure inside the prestressed loading path form, improve theforming quality. Based on the bilinear loading path of tee internal high-pressureforming，have the twist beams numerical simulation analysis, and research theinfluence law of the forming with inner pressure, axial feeding and static frictioncoefficient，get the ideal value of parameters. And twist beams internal high-pressureforming process parameters optimization by using the method of orthogonal testdesign, the twist beams forming quality is better that checked by numericalsimulation.