Numerical crash analysis of composite racing car front impact attenuator by use of explicit FEM codes

In recent decades, improvement of crashworthiness has been achieved by using composite materials, able to absorb large amounts of energy collapsing progressively in a controlled manner. In order to ensure the driver's safety in case of high-speed crashes, special impact structures are designed to absorb the racing car's kinetic energy and to limit the impact of deceleration acting on the human body. To reduce the development and testing costs of a new safety design, it is recommendable to use computational crash simulations for early evaluation of safety behavior under vehicle impact test. This study covers the numerical simulation of crash behavior by using finite element methods and lightweight design of the nose cone as in the Formula SAE racing car front impact structure. Some quasi-static experimental results are briefly reported. Finite element models for dynamic simulations with the non-linear explicit dynamic codes LS-DYNA and Radioss were developed with the emphasis on the composite material modelling techniques and final evaluation and comparison of obtained results with experimental one. The main idea was to demonstrate energy absorbing capabilities of a thin-walled crash box during frontal impact, at the lowest possible initial deceleration. In order to initialize the collapse in a stable way, the design of the impact attenuator was completed with a trigger which consisted of a very simple smoothing (progressive reduction) of the wall thickness. Initial requirements were set in accordance with the 2008 Formula SAE rules final configuration satisfied these requirements.