Aluminium-based Light-weight Bus Superstructure Design to Comply to Global Rollover Regulations

Abstract

The number of vehicle accidents in Indonesia has an upward trend as a consequence of the yearly increasing number of motor vehicles. Rollover accidents, especially those involving bus, have the highest number of fatality due to the limited strength of bus superstructure. Common bus superstructure is constructed by using a standard medium strength steel. This makes the bus has heavy mass with high center of gravity which influences its rollover propensity. Hence, an improvement of bus superstructure with light-weight concept and higher rollover resistance is needed. In this study, a bus superstructure is redesigned by changing its material from steel to aluminium 6061-T6. The new superstructure is redesigned by adding the extruded-roof-edge and by thickening parts that function as energy absorbers during accident. Rollover simulations of the bus with modified superstructure are then carried out using finite element analysis and the superstructure is evaluated by using regulations related to roof crush resistance i.e. FMVSS 216 which uses force method and UN R66 which uses energy method. The results show that the new design of aluminium-based bus superstructure fulfils the FMVSS 216 and UN R66. The results also indicate that by using aluminium material the empty weight of the bus is reduced by 40%, which will improve its rollover stability and fuel efficiency.