Development of a Numerical Technique for Bus Rollover Test Simulation by the FEM

There exists a generalized interest in the improvement of safety issues in buses due to the social alarm brought on by accidents in which buses are involved. Accident statistics show that bus rollover accidents occur with relative low frequency, taking into account all kinds of bus accidents. Nevertheless the risk of mortality in the case of rollover is five times greater compared with any other possible bus accident typology. The object of this paper is the development of a numerical technique able to simulate the mechanical behaviour of bus body sections in the case of rollover. This technique will permit the analysis of different material systems that could be used in the building of buses in order to achieve the best structural behaviour against rollover. Simulations will be based on UNECE Regulation no. 66 (ECE66) specifications: "Uniform technical prescriptions concerning the approval of large passenger vehicles with regard to the strength of their superstructure". Different F.E.M. numerical models are developed and tests are simulated by the finite element method. A sensibility analysis has also been carried out, taking into account several parameters affecting the calculations such as the strain rate and the type of elements used in the model.