摘要

This paper aims at optimising the crashworthiness capabilities of hybrid S-shaped rails of an automotive body under oblique impact loading. In the optimisation process, geometrical parameters, material types and the length ratios of aluminium part to the whole length are taken as design variables. Kriging metamodel techniques are performed to predict the crashworthiness criteria of specific energy absorption (SEA) and peak crushing force (PCF). In the following multi-objective optimisation design (MOD), non-dominated sorting genetic algorithm (NSGA-II) is adopted to obtain maximum SEA capacity and minimum PCF of hybrid S-shaped rails. It is found that the optimum design for a specific load angle does not necessarily guarantee the best solution when the load angle changes. More importantly, the change of weighting factor for each load angle affects the Pareto front of such MOD considerably, and thus selecting proper weights is of great importance in the crashworthiness design of hybrid S-shaped rails.