Selection of the optimal perforated structure in the axial loading of aluminum thin-walled tubes using multi-criteria decision-making: COPRAS method

The use of perforated designs in the manufacturing of thin-walled cylindrical metallic tubes is very common as a suitable option for absorbing energy. In this research, six different geometric designs have been presented to investigate the energy absorption capability of cylindrical thin-walled AA6061 tubes. The COPPRAS multi-criteria decision-making method has been used to select the best geometric design. Initial peak force (IPF), total absorbed energy (E_t), and the specific energy absorption (SEA) of the tubes were considered as selection criteria of the best alternative. The obtained results showed that the perforated tube with unequal circular holes arranged one in the middle is the best option for absorbing energy with simultaneously considering all the criteria. In this optimal geometrical pattern, the arrangement of circular holes is one in the middle with 3 rows of holes, 8 holes in each row, a diameter of the small hole of 5 mm and a diameter of the large hole of 6 mm. In this tube, the IPF, E_t, and SEA values were obtained as 32.04 kN, 1.20 kJ, and 20.88 kJ/kg, respectively.