Response Surface–Based Multi-Objective Optimization of Energy Absorption and Reaction Force in Axially Impacted Thin-Walled Aluminum Alloy Tube

Abstract

Thin-walled aluminum alloy tubes are widely used as energy-absorbing elements in safety structures because they exhibit strong plastic deformation under axial impact loads. This study aims to optimize the axial impact response of aluminum alloy tubes by simultaneously maximizing absorbed impact energy and minimizing the maximum reaction force. The analysis was carried out using numerical simulation of the element method, with a fixed tube length of 50 mm and a constant impact velocity. Varied geometric parameters include tube diameter (15–20 mm) and wall thickness (0.5–1.5 mm). The experimental design was prepared using Central Composite Design (CCD) within the framework of the Response Surface Methodology (RSM). The RSM quadratic model was developed to map the relationships between geometric parameters and the responses of absorbed energy and maximum reaction force. The simulation results show a clear trade-off between the two responses: an increase in absorbed energy is accompanied by an increase in the reaction force. Multi-response optimization is performed using a desirability function approach with equal weights for both responses. The optimization results showed that the optimal design was achieved at a diameter of about 19 mm and a thickness of about 1.1 mm, yielding high absorbed energy with relatively low reaction forces. The methodology and results of this study provide a systematic basis for the design of energy-absorbing elements using aluminum alloy tubes for crashworthiness applications.