## 5 Results and Discussion
### Distification Mechanism  
This section analyzes the failure location in the connection elements, which exceed the yield limit and enter the inelastic range. In all simulations, a plastic hinge forms at a greater distance from the location of the moment plates. Generation of local buckling is also observed, both in the flanges and in the soul of the beam. * Connection Analysis 1-A. In Figure 12a, a maximum stress at 0.02 rad of 520.35 MPa is observed, while in Figure 13a, at 0.04 rad, the maximum stress is 516.12 MPa. Local buckling is generated in the web of the beam. * Connection Analysis 2-A. In Figure 12b, a maximum stress is observed, at 0.02 rad, of 377.39 MPa, while in Figure 13b, at 0.04 rad, the maximum stress is 432.57 MPa. Local buckling is generated in the web of the beam. * Connection Analysis 2-B. In Figure 12c, a maximum stress is observed, at 0.02 rad, of 417.13 MPa, while in Figure 13c, at 0.04 rad, the maximum stress is 455.90 MPa. Local buckling is generated in the web of the beam. * Connection Analysis 3-A. In Figure 12d, a maximum stress is observed, at 0.02 rad, of 369.69 MPa, while in Figure 13d, at 0.04 rad, the maximum stress is 463.28 MPa. Local buckling is generated in the web of the beam. The type of connection proposed guarantees that the plastic hinge is concentrated in an area of the beam exceeding the value \(rh=400\) mm. This is evidence of the generation of a fuse element, following what the ANSI/AISC 341-16 [5] standard established, which specifies that the column and the connection must not fail. The strain for connection 1-A is 20% (Figure 14a), and for connection 2-A it is 12% (Figure 14b). The strain for connection 2-B is 14% (Figure 14c), and for connection 3-A, it is 15% (Figure 14d). The generation of the plastic mechanism in beam-to-tubular column connections filled with concrete, using external diaphragms, is crucial to guarantee good seismic performance of the structure. For the study reported in [34], the plastic mechanism is located 480 mm from the face of the column, which allows energy dissipation and reduction of seismic loads transfer to the global structure. This point is critical due to the high concentration of inelastic stresses and deformations. The present study examines welded connections to the flanges and webs of the beams, where the plastic mechanism is also formed after the welded plates, helping to maintain structural integrity and efficiently dissipate energy. In both cases, the importance of the location and design of the plastic mechanism is highlighted, to optimize the energy dissipation capacity and improve the ductility of the connection. Advantages include high energy dissipation capacity, good ductile behavior, and high initial stiffness. However, there are also disadvantages, such as complexity in construction,higher costs due to the need for precise welds and high-quality materials, complicated maintenance, and the possible need for repairs after an earthquake. In summary, both connection configurations are effective in dissipating seismic energy and exhibit good ductility, although practical implementation and associated costs vary. The choice between them will depend on project-specific factors, such as the availability of materials and technical capacity to perform complex welds. Figure 11: Hysteretic curve (moment–curve): (**a**) for connection _1-A_; (**b**) for connection _2-A_; (**c**) for connection _2-B_; (**d**) for connection _3-A_. Figure 12: Plastic hinge location in connections at 0.02 rad: (**a**) 1-\(A\); (**b**) 2-\(A\); (**c**) 2-\(B\); (**d**) 3-\(A\). Figure 13: Plastic hinge location in connections at 0.04 rad: (**a**) 1-\(A\); (**b**) 2-\(A\); (**c**) 2-\(B\); (**d**) 3-\(A\). Furthermore, modeling the plasticity mechanism using the finite element method is a complex and demanding task. Extreme precision in the material properties representation and boundary conditions is required to capture adequately the nonlinearity of connections under cyclic loading.