| With the popularization of automobiles in today's world,the problems such as energy exhaustion and air pollution are becoming more and more obvious.In this background,it is an important task for the research of automobile to reduce the weight of automobile structure to reduce the energy consumption based on hydroforming.Under the premise of guaranteeing the rigidity and strength of the structure,this technology can reduce the use of raw materials and realize the flexible design of the section of parts,which is one of the effective ways of the lightweight of structure.Loading path is an important factor to influence the effect of hydroforming.Pulsating loading is the optimization of conventional loading path,which can effectively improve the forming quality of parts.This subject is taking the hydroforming of the rear suspension,The wall thickness distribution of the its results based on pulsating hydroforming is discussed.Using the method of combining the experimental test and numerical simulation to carry out the research of forming law of it.Firstly,the regularity of pulsating hydroforming that typical round tube formed to the tube of rectangular section is analyzed.Based on it,the study on the law of rear suspension based on pulsating hydroforming is carried out.In order to investigate the law of rectangular tube based on pulsating hydroforming.A small equipment of hydroforming was developed and built.The cavity structure of rectangular tube was designed and the forming mould was machined.The tests of rectangular tube with conventional loading and pulsating loading were completed and compared.The mechanical properties of the material were obtained by the tensile test of the experimental tube.The results of test and simulation of two loading conditions are compared.The correctness of the numerical simulation was verified.Based on it,The reasons for the higher quality of pulsating loading than conventional loading of rectangular tube were studied by using nonlinear finite element software.The influence of pulsating frequency,pulsating amplitude and pulsating waveform on forming quality of rectangular tube were studied by using it.Based on it,The whole process of rear suspension based on hydroforming was simulated by nonlinear finite element software.The simulation result of rear suspension based on pulsating loading are analyzed.The simulation result based on conventional loading were compared with it.The advantages of pulsating loading were verified.The test of samples of rear suspension was carried out by means of industrial equipment of hydroforming.The experiment and simulation results were contrasted.The correctness of the simulation method was verified.Based on it.The influence of the wall thickness distribution on the friction coefficient between the mould and the tube?annealing treatment?frequency?amplitude and waveform were studied.The reason for the improvement of pulsating loading was the improvement of thematerial performance and the decrease of the friction coefficient between the mould and the tube.In the process of pulsating hydroforming of rear suspension,it was found that only when the frequency was at the critical frequency,the frequency can have a significant effect on the forming result.As the amplitude increases,the forming quality became more and more good.Waveform in accordance with the order of the equivalent internal pressure from big to small,making the forming quality better.As the friction coefficient between the mould and the tube was reduced,the forming quality of tube was better.In the process of forming to anneal,the forming quality of tube could be improved effectively.Through the combination of experimental test and numerical simulation,the analysis of law of rear suspension based on pulsating hydroforming was completed.It provided some reference for the practical application of the technology of rear suspension based on pulsating hydroforming. |
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