Multi-objective optimization of cylindrical segmented tubes as energy absorbers under oblique crushes: D-optimal design and integration of MULTIMOORA with combinative weighting

Abstract

Vehicles experience off-axial loads as well as axial loads during collisions. Hence, it is essential to have oblique loads be involved in investigating thin-walled tubes in vehicles as energy absorbers. In this paper, to find the optimum design of a segmented tube in terms of various collision scenarios, the RSM D-Optimal Design is used along with MULTIMOORA as a multiple-attribute decision-making (MADM) method. The tube consists of three parts having different thicknesses and lengths. Energy absorption, initial peak load, and maximum load in three angles of loads (0∘, 15∘, and 30∘), and masses of the tube were defined as independent objectives. Design points were constructed to obtain all responses through finite elements method (FEM). It was found that the obtained models of responses predict the crashworthiness with acceptable accuracy. Then the optimization provides fifteen Pareto front designs of tubes through fifteen different scenarios. Finally, the integration of MULTIMOORA within a combinative weighting method selected the best tube from the optimums. The contrast between the optimum basic tube and the selected segmented tube demonstrated that the latter was capable of increasing the energy absorption by 24–41%, and reducing the initial peak load by 50–60% for the three applied loads.