Research On The Stretch Bending Forming Process Of Railway Vehicle Side Beam By Numerical Simulation

As the rapid development of rail vehicles and the demand for lightweight materials, aluminum alloy large structural components are widely applied. The stretch bending technology has the benefit of high forming precision as well as a small amount of springback. It has became the main processing craft of large-scale structural components. Because of the large size, complex cross section, high demand of dimensional accuracy, difficulty of forming and large amount of defects of railway vehicle profile beam, it has became to be the technical bottleneck of high quality body manufacturing.This paper takes railway vehicle profile beam as the research object by using numerical simulation, which is based on the in-depth analysis of stretch bending forming and relevant research results of domestic and international. It mainly researches the effect of the stretching in coating stage, die-clearance and the depth of the mold groove on cross sectional distortion. Additionally, the influence rules of pre-stretching、the stretching in coating stage and post- stretching on springback in the bending were analyzed separately. At last, the reliability of simulation software was proved through the stretch bending test. The following several aspects of the results have been achieved:(1) The cross-section distortion will increase with the number of the stretching in coating stage enhances. The cross sectional distortion almost take places in the circular arc. The larger the angle of the arc, the more cross-section distortion will be.(2) The die-clearance should be appropriately larger than the vertical plate thickness of profile. When the die-clearance is extremely small, the resistance between die-clearance and the vertical plate thickness of profile in the in coating stage is large, leading to the profile cannot cover the mold totally and poor contour accuracy. When the die-clearance became too large, the cross sectional easily lead to distortion due to the vertical plate lacking of the constraint from the groove wall.(3) The depth of the mold groove should be appropriately higher than the height of the vertical plate. When the depth of the mold groove is relatively small, cross-section distortion occurs because web of profiles is lacking of the support from mold surface. While the depth of the mold groove is too large, the depth of the vertical plate is lacking of the support from the bottle of the mold groove, which can also make cross-sectionl distortion.(4) Pre-stretching、the stretching in coating stage and post- stretching have different degrees of impact on springback.The less of pre-stretching、the stretching in coating stage and post- stretching, the harder to cause springback phenomenon. The stretching in coating stage has the most significant impact on springback,(5) Using optimized technical parameters and the die after springback compensation can control the contour accuracy of stretching bending parts effectively. Forming parts of high quality was getted finally.