Effect of Welding Process on Energy Absorption Parameters of a Square Tube with Emphasis on the Number and Position of Welding Lines

In this research, thin-walled cylindrical samples with a square cross-section were created by the welding method, considering different welding lines. A total of 21 geometrically similar samples were prepared to investigate the effect of weld lines on the energy absorption parameters of the samples. The results of the study showed that, firstly, the welding process leads to a significant reduction in the energy absorption parameters of the desired structure. Secondly, the position of the welding line is also very effective. The welding line reduces the energy absorption capacity (Ea), and with an increase in the number of welding lines, the decreasing trend of this parameter continues. For example, compared to the sample without weld lines, the energy absorption (Ea) and specific energy absorption (SEA) parameters of the SW4ce sample, with four weld lines in the middle of its sides, decrease by 29.5% and 38.6% respectively. Additionally, the welding process on the samples leads to an increase in the crushing force efficiency (CFE). For example, in the SW4co sample with four welding lines in its corners, this amount reaches about 61.2%, while for the sample without welding, it is 31.3%. Finally, welding reduces the initial maximum force (Fmax). For a sample with four welding lines in its corners (SW4co), this leads to a 59% reduction compared to the sample without welding.