Research On Numerical Simulation Analysis Of Hydroforming Of SUV Rear Sub-frame

In recent years, increasingly high demand for vehicle of energy saving and environmentalprotection is caused by resource shortages and the environmental degradation. Forreducing vehicle weight can well meet the request of car in energy saving andenvironmental protection, vehicle lightweight has become one of the main topics ofresearch in the field of automotive technology. To achieved it, there are two methods:adopting new lightweight materials and using advanced manufacturing technology. Thereare advantages of tube hydroforming technology that better forming quality, fewer partsand molds used, improve material utilization, improve product strength and stiffness andsignificantly reduce the product weight, etc. Tube hydroforming technology has becomeone of the important technologies to promote the development of automobile lightweight.Hydroforming can be used to produce many of the key components in the automotive suchas the rear sub-frame.This paper takes a SUV rear sub-frame as the research object. The rear sub-framehydroforming process is investigated by using numerical simulation and experiment. Therear sub-frame is welded together by transom and vertical arms, so transom and verticalarm hydroforming process needs to be studied separately. Firstly, the finite element modelof transom and vertical arm were built by AUTOFORM. Secondly, based on the initialvalue of process parameters selected, the numerical simulation of transom and vertical armhydroforming was applied, to study the influence of different process parameters onforming quality and the causes of defects. And then, the process parameters are optimizedand the reasonable process parameters are obtained. The optimized loading path was givenby using uniform design method combine with response surface method. The parts oftransom and vertical arm which meet the requirement were obtained ultimately. Finally,optimization parameters were applied to the test of hydroforming of rear sub-frame, theproducts meet the requirement were obtained.