Research On Rollover Safety About Local Structure Of Bus Body Frame Waist Beam

With the development of the automotive technique, vehicle security attracts more and more attention. Domestic research of Bus rollover is carrying out. Because bus rollover accidents will be seriously endangered to the lives of many passengers, the vehicle rollover crashworthiness, or describe it as the strength of the vehicle upper structure, must comply strictly with the relevant standards of bus rollover.Bus Rollover security issues, passenger safety is in the focus of people's attention. At present, China has introducted the ECE R66 regulation as the standards of China's bus rollover. In 1998, GBT17578-1998"Provisions of strength for the superstructure of bus"is implemented and the passive safety of bus is more normative.The laboratory have researched into the finite element model about rollover safety of the whole bus body structrure and find the connection of the local structrure is fatal in an rollover accident. The connction of the roof and the side wall ,the connection of the waist beams that large deformation happens. The local connection of bus waist beam have large deformation when rollover happens that causes the living space of passengers violated. It will impact the protection of body structrure against passengers. Therefore, this issue will be sampling the local connection of bus waist beam as a separatly part to analysis. By simulating a number of different bus connections, finding a suitable structure of the waist beam connection. Finally, simulating the body section of the bus verifies the types of connections rationality and feasibility.In this paper, the introduction of bus connection model is the base of the whole bus rollover simulation and it must be similar to the connection of the bus. It investigated numbers of the connection about the structrure and simplified prototype of the connection. Finally, determining the three connections that this paper contains. Then,basing on ECE R66 regulation,creating the simulation program of the waist beam connection rollover model. Then, adjusting and improving simulation methods, to achieve a higher computational efficiency. By anasysing the six connection models'results, finding the rules of the models about the deformation and then creating a optimized connection.In the ECE R66 regulation, to some extent,the test of the body section can replace the test of the whole bus body structrure. It contains that creating the load ,rollovering the section body and measuring the characteristics. Entire vehicle FEM model establishment is a heavy workload, the work is generally completed by lots of people. Against to the characteristics of bus rollover impact simulation, this study simplify off some parts that have little influence on the crashworthiness. In this article,it creats a closed loop of the bus frame to instead of body section. When rollover happens,closed loop accepts the main impact. The idea of the closed loop has played a very important role in the simulation of the whole bus structrure. Therefore, it extracts a typical body section from a bus frame, and then extracts closed loop of the body section,finally rollovering it and anysis the simulation results. For the purpose of the application in the whole bus model,it creats bus frame closed loop model and adds the results of the connections into closed loop model. By comparing the two results of the closed loop model, we know the important role of the bus connecting. Computer simulation method is good, but computer simulation can not completely instead of whole bus frame test. Computer simulation results that are correct or not must be test by the experiment. In view of this situation, the beginning of this study and there is no single model simulation of the rollover collision, but to carry out the tensile testing of materials, measured the two materials simulation Q235 and 16Mn stress - strain curves.The disadvantage of this issue is that there is no exeperiment test to verify the simulation results. By comparing the simulation model and analysis of the results, research and explore the finite element method of dynamic simulation, in-depth finite element method and use the rollover to the analysis of the basic skills of the collision, the main parameters of configuration and so on.Superstructure strength research of the domestic bus so far is still relatively little, Therefore, the majority of buses are not related to the design of the guidance and expertise. China's passenger car industry is now in a strong development phase, if we want to go abroad, and occupy Europe and the United States markets, the study on the Bus Rollover must be intensified. Formulate a mandatory standard, the corresponding test facilities, and the corresponding development of computer simulation studies.