Rollover analysis for the body section structure of a large bus using beam and non-linear spring elements

In the case of bus rollover, the body structure of a bus should be designed to ensure a survival space for passengers. This study focused on evaluating the rollover strength of a large bus at the initial stage of vehicle development. For this purpose, the section structure of a large bus was first modelled using simple beam elements, and the impact boundary conditions required by United Nations Economic Commission for Europe regulation 66 were applied. In order to validate the beam element model, the simulation results were compared with those of the shell element model and real experiments. Since the analysis error with the beam element model was mainly caused by the difference in strain energy at the connecting joint, the joint connection was modified with non-linear springs to account for the local buckling. With the improved beam model, the results were in good agreement with those of the shell element model and physically measured values, and the simulation time was much reduced.