Application Of Crossbeam Joints Form Optimization In The Performance Improvement Of White Body

With the advancement of technology and the enhancement of people's consciousness of energy saving and environment protection, vehicles develop towards safety, comfort, energy saving and environment-friendliness. The optimization design of automobile structure is an effective measure to improve vehicle performance and to realize energy saving and emission reduction. As the key transition region and the main force transmission components, the structure of automobile joint directly determines the torsion stiffness, bending stiffness and vibration mode of vehicle body. A detailed study on automobile joint is beneficial to improve the quality of body and has important theoretical value and practical significance. In view of an actual situation that most of current researches about automobile joint are focused on main body joint instead of crossbeam joints, this paper delved into the effect of crossbeam joints form on body stiffness performance. The main results are as follows:(1) A finite element model for body in white (BIW) of a commercial vehicle was set up based on HyperWorks. The bending and torsion stiffness of this model were analyzed, and the deformation and stiffness values of BIW were obtained. Accordingly the stiffness test had been finished. Results comparison between simulation and test verified the rationality and reliability of model.(2) With total body mass as objective function, torsion and bending stiffness as constrained function, the sensitivity of body performance to plate thickness was analyzed based on sensitivity analysis theory. The contribution ratio of crucial module to bending and torsion stiffness were obtained and it was found that the contribution ratio of crossbeam module to torsion stiffness is obviously low, which is only 0.79%.(3) The effect of the crossbeam joints form on the performance of BIW stiffness was studied and the joints form was optimized. The results show that the BIW stiffness is best obtained by using segmented joint. With the optimized joint form, the contribution ratio of crossbeam module to torsion stiffness increases obviously, which reaches 4.68%. The optimization design of a similar vehicle show that improving the crossbeam joints form is an effective way to enhance stiffness and realize lightweight.