Research On The Design Of Coach Body Frame Based On Rollover Safety

Coach traffic accidents mostly include rollover, front-impact, side-impact and rear-end collision. In particular, the traffic accident caused by rollover is usually more serious than the others, which often makes massive death and injured. The coach body frame plays an important role in rollover safety. The previous researches indicated that the main reasons for casualties in rollover are the invasion of residual space and the serious impact between coach structures and passengers. Taking the rollover safety design of a Zhengzhou Yutong coach as an example, the design methodology and the operation procedure of the coach body frame based on the coach rollover safety are illustrated in this paper, and the factors affecting coach rollover safety such as closed-loop structures, cross-sectional of side window pillar, thickness and material are researched, besides, the improvement design of coach structures based on rollover safety is proposed.The concrete research of this paper includes four parts as follows:1) After investigating and summarizing the current situation of coach traffic accidents, the importance and urgency of the research on coach rollover safety are elicited, and the design idea of coach structures based on rollover safety is proposed.2) Taking the rollover safety design of a Zhengzhou Yutong coach as an example, the paper established a finite element model of coach body frame made up of shell elements and solid elements. The modal analysis, the bending stiffness analysis and the bending stiffness experiment are carried out to verify the validity of the finite element model.3) The theory of finite element simulation and the method of establishing model are illustrated. Based on the verified model, the finite element model of coach rollover containing residual space and passenger head is established. And the dynamic simulation of coach rollover impact is carried out by Ls-Dyna. The Simulation results show that the safety of this model is unqualified.4) The theory of coach rollover is illustrated, and some concrete proposals for improving the safety of coach rollover are presented. Besides, the paper analyzed and evaluated the influence on rollover safety by using different improvement methods. The results show that the use of closed loop, the optimization of window pillar section shape, the increase in wall thickness and the improvements of mechanical properties could greatly improve the anti-rollover safety, and finally improve the original model by using improvement measure, the result proved the rationality and effectiveness of the original model.