Behaviour of an Impact Attenuator for Formula SAE Car under Dynamic Loading

During the design of a Formula SAE car is necessary to take into account also its behaviour under dynamic loadings, such as frontal impact against a rigid wall, in order to make a safe car in case of an accident. In particular the racing car must have structural devices able to absorb most of the kinetic energy with their progressive crushing minimizing forces and decelerations transferred to the pilot. So the purpose of this study is the design of an impact attenuator for a Formula SAE car and the investigation, through both a numerical and experimental approach, of its dynamic behaviour under frontal impact conditions. The crash-box is obtained by the combination of sandwich panels and aluminium sheets. Firstly experimental tests and numerical analysis on sandwich structures were carried out in order to better understand their behaviour and model them properly. Afterwards a total 3D numerical model was built with the finite element code ANSYS and solved with the non-linear dynamic software LS-DYNA. In order to obtain the best configuration of crash-box in terms of maximum absorbed energy, minimum deceleration and weight saving an optimization process has been done varying some geometrical parameters. Finally a crash-test was done on the real impact attenuator in order to compare the experimental results with the numerical ones. The obtained results show that the crash-box designed and built is able to absorb the total impact energy with progressive and plastic deformation and contain the average deceleration under a 20 g value.