Optimization of energy absorption properties of thin-walled tubes with combined deformation of folding and circumferential expansion under axial load

Recently, the combined mechanism of energy absorption has been considered for increasing energy absorption efficiency. The combined deformation of circumferential expansion and folding in the cylindrical aluminum thin-walled tubes is one of these mechanisms that can be effective in improving energy absorption. In this paper, the effect of parameters of diameter, height and thickness of the tube, friction, and interference of the tube and punch, as well as the half-angle of the tip of the conical punch on the energy absorption have been investigated using LS_Dyna software. Taguchi method was used to design the experiments and response surface method was used for optimization. In the Taguchi method, the design limit has been significantly reduced and the effect of different parameters on energy absorption has been demonstrated. In optimization with response surface method, optimal states have been proposed that increased energy absorption compared to reference test. Finally, by providing a mathematical model for single-objective optimization, the specific energy absorption increased by 127%, but the maximum force in this case was increased by 130%. In multi-objective optimization, specific energy absorption and maximum force were considered as design parameters that optimized specific energy absorption increased by 77%, while the maximum force was only 37% higher. Thus, by combining suitable types of energy absorption mechanisms and optimizing them, absorbents with a higher specific energy absorption capacity and lower maximum force were designed.