Safety Analysis And Test Verification Of Bus Rollover Based On Skeleton Stiffness

With the rapid development of passenger transport industry,the bus fleet increases year by year.Events of many passengers deaths have occurred because of bus rollover accidents,which have caused the government and enterprises’ attention.Passenger passive safety and safety body structure have become research priority and focus about modern bus technology.The new rollover test standard GB 17578-2013 "Requirements and test methods of strength for the superstructure of bus" has been enforced,which encourages enterprises to further focus on bus rollover safety.In this context,this paper carried out certain 13 m bus to do bus body frame static stiffness analysis and simulation about bus rollover feature.This paper takes a 13 m long bus as the research object.First,UG 3D skeleton model is established according to CAD drawings.Finite element skeleton model is established by finite element software Hypermesh.The modeling method and precautions of finite element model are expounded in this paper.The stiffness of the skeleton finite element model is analyzed.By the analysis,the torsion stiffness and bending stiffness of the bus are obtained.At the same time,complete test flow is formed by exploring the bus rigidity test method,developing the test programs and designing test tooling.The very credible result of torsion and bending stiffness of the bus is obtained.The skeleton finite element model is verified by the comparison of the simulation results and the stiffness test results.In this paper,bus rollover simulation finite element model are established in Hypermesh.Using LS-DYNA to do the bus rollover simulation calculation,the results are processed by Hyperview and Prepost.The bus deformation,the variations of the survival space invasion and the variations of energy and acceleration are analyzed to evaluate the bus rollover safety.The test method,flow and attention of the bus rollover test are studied to put forward the test evaluation method.The bus rollover test is carried out.The accuracy of the simulation is verified by comparing the result of the bus rollover test and the bus rollover simulation calculation.As the simulation and test results show,the front survival space of the bus has been invaded.But,the middle and rear survival space has a large distance.As a result,the front survival space of the bus does not meet the requirements of the regulations.According to the result,a local improvement study is conducted to strengthen the front and side structure of the bus.According to the regulation on bus section test,the improved model of the bus section is analyzed and verified by the simulation and test.Compared with the calculated results before the improvement,the bus section has a large survival space invasion.The analysis and test results show that the structural improvement effect is obvious.The test result of the bus meets the regulation requirements.