Research On Rollover Bus Body Frame With Beam Shell Hybrid Simulation Model

At present, vehicles have become a living part of the indispensable, but also caused by traffic accidents to human life and property posed a serious security threat. Now, the vehicle safety studies are attracting increasing attention.Bus Rollover security issues, passenger safety is in the focus of people's attention. Bus Rollover against domestic research are also being launched, and the main method is to use the finite element analysis method on the Bus Rollover simulation calculation. In the application of CAE simulation analysis on the Bus Rollover, normally used shell element beam element and two models.Beam element modeling have the following main advantages: Modeling facilitate simple, small-scale model to calculate speed, easy to model changes from the overall framework of the bus to evaluate the stress level. However, this method does not consider joint shape, strengthen connections, as well as local details directly rigid joints to connect nodes, making stiffness ratio calculated by bus to the actual stiffness, but impossible to calculate the joint part of the stress concentration, not be able to demonstrate part of the Joints Local Laws. Shell unit relative to the bus detailed modeling, almost not simplified, but the shell element modeling has its shortcomings can not be ignored: Modeling workload and time-consuming, large-scale finite element model to calculate consumption, not model Laws, not suitable for use in structural optimization process.Passenger vehicle models usually contain more than one million units and nodes, in the use of shell element, if the model requires changes to the very inconvenient, great impact on the efficiency of analysis. Although the use of beam elements can save time, improve efficiency, but not the precise structure of the stress response and local deformation.Based on the beam element and shell element its own characteristics and the requirements of Bus Rollover simulation, this paper presents the use of mixed beam shell model Bus Rollover simulation. In theory, the hybrid model can be both beam element model and the advantages of shell element, weakening two shortcomings.Shell mixed beam element model analysis method is the main beam element and shell element mixed finite element model. The focus on the structure of the use of shell element modeling, the general structure of a beam element modeling, but also the local area twice refinement. This method using both beam element shell element modeling and the advantages of avoiding the use of a single beam or shell element modeling the shortcomings of modeling can greatly improve efficiency, reduce computation time. Therefore, at present, this method of large buses in finite element analysis applications limited. If the body finite element model was further refined requirements, but also flexibility with the use of beam elements, such as multi-point constraint to simulate the structure of body welding, riveting and bolt connections, and other connections.In this paper the structure of the bus beam shell hybrid model, a simulation of the bus rollover. In the establishment of hybrid model in the process, focus on the following questions were analyzed: the determination of mixed model unit, the unit connected with the definition of contact, and conducted a preliminary definition of the unit and the time step size, etc. parameters on the efficiency and accuracy of the impact.According to Bus Rollover in the main reaction of several parameters on the accuracy of the hybrid model calculation accuracy carried out a detailed comparative analysis of the main parameters of the output of the "living space", acceleration, to be able, through this paper above that several initial parameters a hybrid model is applied to the analysis of Bus Rollover feasibility and the effectiveness of precision.To further analysis on the Bus Rollover mixed model analysis of the feasibility of this model and make use of shell set up a mixed model of a certain vehicle models model, and completed the simulation of vehicle rollover. In the mix of vehicle model simulation analysis, the focus on the model of the load imposed, the time step of settings, such as the choice of regional contacts are analyzed and different degrees of simplification. Finally, the vehicle will be the hybrid model calculated results and the whole shell model "living space" in computing time, acceleration, to be able to make the comparison, and further demonstrated that the hybrid model is applied to the analysis of the simulation Bus Rollover effectiveness Vehicle Rollover from the simulation results can be seen, the paper used by the security model in Rollover Although meet compliance requirements, but still needs to be enhanced. China's passenger car industry is now at a stage of rapid development, if you want to keep up with the pace of international development, the Bus Rollover issue must intensify its research efforts. Formulate relevant compulsory standards, the establishment of the corresponding test facilities, and development with corresponding computer simulation of research to improve the efficiency of bus development, the cost savings can be made so as to keep pace with the development of a bus, the development of China's bus industry.