# Numerical Simulation of T Joints Constructed from Hollow Steel Sections
## 4 Analysis of the Results  
For the studied \"T\" connection type, a comparison between the analytical solution and experimental findings was carried out, in addition to the outcomes of the non-linear numerical analysis. In this investigation, local deformations in the connection area were evaluated both qualitatively and quantitatively, and stress fields were examined qualitatively. The following factors determined the connection's ultimate carrying capacity:  
* EC 3 [9], applying nominal yield strength;
* EC 3 [9], applying experimentally determined yield strength;
* Analytical model, considering the effect of welds;
* Experimentally determined load-bearing capacity of connections. The von Mises stresses in the stress concentration zones were found to be far more than the material's ultimate strength during the preliminary research's mesh convergence study. It is possible to trace this disparity to the FEM computational approach. More specifically, only in elastic regions can the solution findings be accurately extrapolated from integration points to nodes. When plasticity is present, the results could be inaccurate since the behavior of the material inside one element is not well captured by linear extrapolation. Reducing the element size or the separation between integration points and nodes could help to minimize errors. The ERESX command [31], which is implemented through the ANSYS APDL snippet, can also be used to regulate the extrapolation. It can be specified to copy or extrapolate findings from integration points to nodes. An exaggerated increase in stresses, well beyond the ultimate stress, was found at the transition from the elastic to the plastic region in the von Mises stress distribution with allowed extrapolation, during a stage where a considerable portion of the chord's top side was in the plastic region. By minimizing the discrepancy between the value at the integration point and the extrapolated value, decreasing the element size may result in stresses that are more realistic. Nonetheless, to stop the yielding zone from spreading, a very fine mesh must be achieved in a sizable zone. An alternative strategy would be to either fully or partially activate the extrapolation. Values are copied from integration points to nodes in the first scenario, and extrapolation is limited to elements that have not surrendered in the second scenario. Stresses greater than the maximum strength, however, could still happen in the second scenario. Extrapolation was fully removed for the mesh convergence research and the final calculations. Contour plots that show the stress field and deformation are used to visually represent the analytical results or typical output data. The designations \"MX\" and \"MN\" in these figures indicate, respectively, the maximum and minimum values of the relevant output data. The local deformations of the y-direction components of the \"T\" connection for different load values are shown in Figures 3-6. Using the previously described methods, the applied stress level was set to match the bearing capacities of the connections under investigation. Table 2 provides comparative representations of maximum local deformations and ultimate carrying capabilities of connections obtained using the non-linear analysis. It is clear from Figures 3 and 4 that the major local plasticization of the chord element's flange surface caused the greatest distortion to occur close to the weld, at the point where the brace and chord meet. The maximum and minimum local deformations in the direction of the \"T\" axis were, respectively, 0.588 and 0.688 mm. The resulting value of the local deformation, when the seams are taken into account in the analytical model, was 1.682 mm, which is substantially closer to the experimentally determined deformation of 2.400 mm. When comparing the connection's bearing capacity to the bearing capacity calculated using the nominal value of the yield strength, the difference was 2.16.