Bohai Steel Structure Co., Ltd.

ATTEN: Manager Liu

phone: 18812088818

QQ: 779701873

ADD: Longhua Development Zone, Jing County, Hengshui City, Hebei Province

2.2 Material characteristics of square steel tube beam and column of material model are shown in Fig. 5. The stiffening rib and the material used in beam and column phase carcass value. The elastic modulus E = 161249.7 MPa and Poisson's ratio_ = 0.3 are used in the multilinear material model. The yield criterion adopted in the model is Von Mises yield criterion, and the material is considered to be isotropic 2.3 finite element model. ANSYS software is used to establish the finite element calculation model for the joint shown in Figure 3. Because the ratio of the length and width of square steel tubular beam-column to its wall thickness is replaced by She181, a shell element with six degrees of freedom at each node, the element has the function of stress rigidization and large deformation, and has strong non-linear function; the additional stiffening rib uses tetrahedral element solid92, and no joint has three degrees of freedom, which supports plastic. The top and bottom slabs of square steel tubular column adopt soid45 element and assume that it is rigid, and the end rigidity of square steel tubular beam 1 is added.

The finite element model of the joint is established for the body element and the shell, as shown in Fig. 4, and the mesh of the element in the node domain is refined. Finite element model of axillary joints with edge 4 at the bottom of square steel tubular column and hinge at the top (material constitutive calculation results of axillary joints with thin-walled square steel tubular beam and column, figure 5, analysis of 31 load-displacement curves, Figure 6 load-displacement curves of axillary joints with thin-walled square steel tubular beam and column, figure 6, load-displacement curves of the joints, is at the beginning of the elastic stage. The load and displacement increase linearly. When the load reaches 13.23kN, the joint begins to yield, and the corresponding yield displacement is 7.4mm. Then it enters the yield stage and reaches the plastic development of 2553k section. The ultimate bearing capacity of the joint can be calculated to be 26.33kN, which is slightly larger than that of the finite element calculation. The moment-rotation curve of the joint is similar to that of the load-displacement curve. At the same time, the initial rotational stiffness of the joint is 847.5kN.m, which is the elastic modulus of steel, the moment of inertia of the girder's quadrangle, the span of the girder is_b, and the K B = 8 (braced frame) or K B = 25 (unbounded frame) can be calculated to be a semi-rigid connection when the bending capacity of the connection is taken as the criterion. Definition: The plastic bending moment of the joint is; the plastic rotation angle at the end of the beam is: U.

The relative bending moment and angle curves of the joints can be obtained as shown in Fig. 7. It can be seen that the relative bending moment and angle curves of the joints are located in the semi-rigid connection area and are quite different from those of rigid or articulated joints. Therefore, such joints can not be simply considered as rigid joints or articulated joints. Fig. 7. Relative bending moment and angle bending 32 stress analysis Fig. 8 (bullet) Sexual stage) and Figure 9 (ultimate load action) are the stress development trend of each section along the length direction of square steel tube beam 1. The bending stress of the girder can be approximately triangular distribution from element 1 to column wing direction and from section H to section height of the girder 8 [a). The shear stress is approximately parabolic distribution, and the shear of the web of the girder at each section should be roughly equal. It conforms to the classical beam theory. Mises stress distribution is also approximately parabolic, but with the distance from the surface of square steel tubular column, its stress changes more.

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