Frontal impact on bus superstructure as per UNECE R29 and NCAP

Abstract

Frontal crash for the large vehicle is less severe compared to the lightweight vehicle due to the height position of the driver compartment in the vehicle which sits well above the impact area in any accident involving a passenger vehicle. Due to this reason, most of the coachbuilder does not include crumple zone in their design as what the car's manufacturer did. However, in the case of frontal collision between two large vehicles or with the rigid wall, the possibility of energy absorption of the structure is very low and the remaining energy will be transferred directly to the driver and occupants. In this respect, two prominent regulations for frontal impact, namely United Nation Economic Commission of Europe (UNECE) Regulation no. 29 and New Car Assessment Program (NCAP) is used to determine whether the structures are having enough strength to withstand the load produced by the impact. This paper deals with the finite element simulation of a frontal impact on bus superstructure by applying both of the regulations. Then, the results for both simulations are compared in terms of energy produced, structure deformations, maximum stress, and the corresponding plastic strains. It is found that the energy from the ECE R29 regulation is lower than NHTSA's NCAP with 55 kJ and 142 kJ respectively. However, the deformation observed from R29 simulation, the front structures is severely deformed. Meanwhile, the structures in the NCAP simulation are still intact and the steering wheel structures are still not in contact with any body parts of the driver.