Investigation of rollover performance for Malaysia bus superstructure

Abstract

Accidents involving bus rollover can be classified as one of the most fatal types compared to other types of motor-vehicle accident. There are various aspects that lead to occupant injury and fatality. Two prominent aspects are superstructure strength and occupant kinematics. This study deals with the two stages of analyses which are superstructure strength having rollover and occupants kinematic analysis. In accordance to UNECE R66, the bus superstructure should be able to withstand the impact load produced by the rollover accident. The validation process using finite element model was done by comparing the strain results obtained from simple box rollover experiment with the simulation results. A total of four full-scale models of the bus superstructures had undergone rollover simulation using finite element analysis software. The predicted results suggested that the structural strength having rollover strongly depends on the bus design parameters in terms of the beam profile size and main bus dimensions. Analyses of the occupant kinematics were also included in this study. Occupant’s injury of restraint occupant was compared to unrestraint occupant using the Mathematical Dynamic Model (MADYMO) software. Overall, the injury indexes for unrestraint occupant are greater than that for restraint occupant. By using a restraint system, the occupant injury and number of fatalities can significantly be reduced.