Improvement of the Energy Absorption Capacity of an Intercity Coach for Frontal Crash Accidents

According to the accident statistics for buses and coaches, accidents involving frontal crash constitute an important percentage among all bus accidents. In this type of accidents, front body of the bus structure gets severely damaged and this puts the driver and crew in great injury risk. And most of the frontal crash accidents result in death of the bus driver. Because of this, the safety of both the bus driver and the crew should be ensured in the case of frontal crash accidents. Providing the driver’s safety is crucial since the driver is the key person for keeping the control of the bus in the event of an accident so that the safety of the passengers will be ensured. Even though the most of the passive safety standards are related to the safety of the passengers, some international regulations exist for the driver’s safety for heavy vehicles. The European regulation ECE-R29 is arranged to provide the safety of the truck cabin and the driver. This regulation involves a frontal crash pendulum test in which a plate with a specified mass strikes the cabin of the vehicle. A regulation specifically arranged for the safety of bus/coach in the case of frontal crashes does not exist, but some proposals similar to ECE-R29 are being discussed in Working Party on Passive Safety (GRSP) in United Nations Economic Commission for Europe (UNECE). Presumably, a similar regulation for buses will be imposed in the near future. In this paper, frontal crash analysis of the structure of a bus front body was performed according to the ECE-R29 European regulation requirements and the strength of the bus structure was checked whether the safety requirements are satisfied. The nonlinear explicit finite element code LS-DYNA® was used for the crash analyses. The first stage of this study involves the frontal crash analyses of the baseline bus structure without any improvements. At this stage the weak parts of the front end structure of the bus body were determined. In the next stage some improvements were made on the bus structure in order to strengthen the front body. These modifications include the rearrangement of the weak profiles forming the bus front structure. Finally the modified bus structure was compared with the baseline model if the requirements for the driver’s survival space were satisfied according to ECE-R29.