Crashworthiness and lightweight optimisation of thin-walled conical tubes subjectedto an oblique impact

Abstract

Two major requirements for a vehicular system's crash components are being lightweight and having good crashworthiness. Thin-walled round and conical tubes, which are either empty or foam filled and that can potentially be used as the front rails of a passenger car subjected to oblique impact, are numerically analysed using the finite element method. The conical tube was found to have the best performance in terms of both specific energy absorption and peak crushing force. A maximum of 106.6% increase in the specific energy absorption was observed for the empty conical tube than the foam-filled round tube in the load angle range of 0°–30°. Using the Kriging metamodels with a maximum relative error less than 4%, multi-objective design optimisation of the conical tube was performed with a weight constraint of 0.2 kg. Lightweight and improved crashworthiness were obtained simultaneously for the conical tube through optimisation. It was also found that the optimal tube configurations differ for different impact angles. However, including multiple load angles in the multi-objective design optimisation process is feasible and could result in improved robustness of the tube against oblique impact.