This work aimed to analyze the behavior of the rear structure region of an
electric bus in a rear collision situation and to create mechanisms capable of
absorbing the energy generated by the impact, to guarantee the integrity of the
batteries. These, when damaged in a collision, can release different types of
flammable electrolytes, and even start a fire, creating a great risk to
passengers and other people near to the vehicle. For this purpose, an impact
absorber was developed to protect the batteries. Studies were carried out on
rectangular cross-section profiles for programmed deformation, known as crash
boxes (which aim to convert kinetic energy into deformation energy). Proposals
were created based on concepts obtained in the literature and numerically
evaluated through explicit numerical simulations based on other similar
articles. From these studies it was possible to obtain higher values of energy
absorption when compared to a square tube of the same cross-section. After the
individual simulations of each crash box, the most effective proposal was
applied to the structure together with the other components of the vehicle’s
rear structure, these with the function of directing the residual energy to more
rigid regions of the vehicle, such as the chassis stringers and its crossbeams,
regions connected to the bus body structure. The complete impact absorber
validation methodologies were developed specifically for this work based on
CONTRAN Resolution No. 629 - Appendix II, which refers to the pendulum test, due
to the fact that there are no standards for buses regarding safety of batteries
in case of collision. The crash boxes applied to the structure reached an
efficiency of approximately 45% of the kinetic energy that was imposed on the
impact cell converted into strain energy. In addition, the vehicle was able to
meet the proposed approval criteria for the absence of contact between the
structure components and the batteries. The methodology was considered efficient
in order to represent a collision of a small vehicle in the back of the bus.