# Numerical Simulation of T Joints Constructed from Hollow Steel Sections
## 4 Analysis of the Results
This discrepancy results from the theoretical presumption of rigid-plastic behavior of the material at the connection point in the analytical model where the influence of the seams was taken into account. Nonetheless, these results demonstrate that there is a strong correlation between the link and its elastic-plastic nature. Figure 4: Local deformations of “T” connection in mm (\(\gamma\)-direction) for ultimate bearing capacity of connection determined by EC 3 with experimentally determined yield strength. Figure 5: Local deformations of “T” connection in mm (\(\gamma\)-direction) for ultimate bearing capacity of connection determined by analytical model considering the effect of welds. For a load equivalent to the bearing capacity found by experimentation, the numerically computed local deformation was 2.388 mm, which is in good agreement with the deformation recorded experimentally. Figures 7-10 show characteristic depictions of this stress together with the matching numerical value legend. The yield strength and the maximum equivalent stress in the base material at the connecting zone were generally comparable. The sudden peaks on the stress diagram indicate that there was a severely non-uniform stress distribution in the field of equivalent stresses at fillet welds and in certain zones on the side vertical walls of the chord element. In certain places, the maximum equivalent stress at the welds even exceeded the weld material's yield strength. The tension on the side walls of the chord element approached the material's ultimate strength. Based on these data, it can be concluded that the connection model under investigation reached a breaking point--a situation that did not arise during the connection's experimental study. It is noteworthy that the impact of these occurrences [31] was strictly confined, encompassing a relatively tiny area. Furthermore, at these high stress levels, local plasticization took place, changing the modulus of elasticity to a much lower value and leading to noticeably lower stresses. Due to the failure corresponding to the local deformation requirement occurring at a load level insufficient to produce high stress levels over broader areas, this occurrence had a limited character. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Ultimate Bearing Capacity** & **Ultimate Bearing Capacity of** & **Max Local Deformation** & **Max Local Deformation** \\
**Determining Procedure** & **Connection [daN]** & **NNA [mm]** & **Experimental [24] [mm]** \\ \hline EC 3 with nominal yield strain & 2.1913 & 0.588 & 0.93 \\ \hline EC 3 with experimentally & 2.5040 & 0.688 & 1.02 \\ determined yield strain & 4.1250 & 1.682 & 1.69 \\ \hline
\begin{tabular}{c} Experimentally \\ determined value \\ \end{tabular} & 4.7340 & 2.388 & 2.40 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of ultimate bearing capacities and local deformations. Figure 6: Local deformations of “T” connection in mm (\(\gamma\)-direction) for experimentally determined ultimate bearing capacity of connection. Figure 8: Display of equivalent stresses at the connection in daN/mm\({}^{2}\) for ultimate bearing capacity of connection determined according to EC 3 with experimentally determined yield strength. Figure 7: Display of equivalent stresses at the connection in daN/mm\({}^{2}\) for ultimate bearing capacity of connection determined according to EC 3 with nominal yield strength. Figure 9: Display of equivalent stresses at the connection in daN/mm\({}^{2}\) for ultimate bearing capacity of connection determined by using analytical model, considering the effect of welds. In the non-linear numerical analysis, the experimentally determined values of the bearing capacity corresponding to the limit displacement, and the results of the bearing capacities and deformations determined in accordance with EC 3 calculation processes were compared.