Avaliação da absorção de energia durante colisão de uma longarina origami soldada pelos processos RSW e GMAW

Abstract

The continuous growth on the number of vehicles on the big cities and the increase on the average speed allowable on the streets creates a scenario where the number of automotive accidents are more often. The statistics published by the Brazilian Nacional Confederation of Transports shows that the number of casualties due to automotive crash has increased 3.3% in 2019 in respect with 2018. Due to the high number of casualties and expenses with recue and medical treatments, the governments across the world have been adopting more tight safety protocols to homologate and classify the safety of vehicles. Therefore, becomes mandatory for the development of a new car to consider the strength of the occupant compartment and the energy absorption capacity of the vehicle’s frontal structure. In this paper, two different welding technologies, RSW and GMAW, were analyzed in the same geometry of an automotive crash box. The geometry of the crash box was defined using the “Origami Engineering” technology through a numerical optimization with a target of maximizing the energy absorption. The crash boxes had the performance and deformation mode evaluated when crushed against a rigid wall at high speed. The specified welded joint was capable to increase the performance of the origami crashbox in 20% when compared in simulations with a seamless origami crash box. When compared with a thin-walled square tube the performance increment is up to 50%. The GMAW weld has shown a better capacity of guiding the octagonal deformation mode, which is desirable due to the higher efficiency. The RSW despite of the productive advantages has shown a mix mode of symmetric and octagonal. The simulation results were confirmed in physical tests with a correlation of 85%.