Simplified numerical simulation method for nonlinear semi-rigid joints of steel beams and columns

Abstract

The present invention relates to a simplified numerical simulation method for a nonlinear semi-rigid node structure of a steel structure beam-column, belonging to the field of architectural technology. A finite element solid model is established based on ANSYS, and the bending moment rotation curve at the node and the load-displacement curve at the beam end are extracted based on the solid model. The total deformation at the beam-column node is simulated based on the COMBIN39 unit in ANSYS. An equivalent simplified model is established based on the finite element solid model, and the rotation capability of the node is simulated using the COMBIN39 unit in ANSYS. The bending moment rotation curve at the node extracted from the solid model is assigned to the COMBIN39 unit. The simplified model is then subjected to the same boundary conditions and loads as the finite element solid model to obtain the load-displacement curve at the beam end. The obtained data is then analyzed and verified. The nonlinear semi-rigid node solid element of the steel structure beam-column is simulated using the combination unit based on ANSYS, which greatly reduces the number of modeling meshes and the complexity of contact settings, while ensuring the reliability and authenticity of the research.

Description

Technical Field

[0001] The present invention relates to the field of building technology, and in particular to a simplified numerical simulation method for a nonlinear semi-rigid node structure of a steel structure beam column. Background Art

[0002] Beam-column connections, as the primary component of structural connections, are responsible for transmitting axial forces, shear forces, and bending moments. The mechanical properties of these connections largely determine the deformation capacity of the structure. Currently, the design of beam-column connections is generally simplified to either rigid or hinged connections. In reality, completely rigid connections and ideal hinged connections do not exist. Designing with completely rigid connections overestimates the negative bending moment transmitted from the beam ends to the columns and underestimates the mid-span bending moment. Designing with ideal hinged connections underestimates the negative bending moment transmitted from the beam ends to the columns and overestimates the mid-span bending moment. Semi-rigid connections significantly affect the mechanical properties of structures.

[0003] Currently, domestic and international scholars have conducted extensive testing and theoretical analysis on the mechanical properties of various types of semi-rigid joints. The Chinese Technical Code for Steel Structures with End-Plate Semi-Rigid Connections (CECS 260:2009) and the Steel Structure Design Manual propose approximate methods for initial rotational stiffness, bearing capacity, rotational capacity, and deflection for specific types of semi-rigid joints. China's "Steel Structure Design Standard" stipulates only that when semi-rigid beam-column connections are used, the effects of changes in the beam-column angle should be taken into account. The internal force analysis should assume a moment-rotation curve for the connection, and the joint design should ensure that the joint construction conforms to the assumed moment-rotation curve. It can be seen that the design of semi-rigid nodes in China has not yet been popularized, mainly because the current mainstream structural design software (YJK, PKPM, etc.) cannot realize the design of nonlinear semi-rigid nodes, and there is no relevant calculation formula to calculate the internal force after applying semi-rigid nodes. The use of finite element software for solid modeling design requires a lot of time and energy to set up each component and contact of the model. In addition, it is troublesome to modify the model, the calculation time is long, and the nonlinear factors brought by the contact make the convergence calculation complicated. It is also difficult to obtain the internal force diagram conveniently, making it difficult to apply to the design of the entire building.

[0004] The mechanical properties of semi-rigid joints in steel beams and columns have been extensively studied, but structural design software lacks a corresponding implementation method for semi-rigid joints. Therefore, a simplified numerical simulation method for nonlinear semi-rigid joints in steel beams and columns is urgently needed to address these issues. Summary of the Invention

[0005] The present invention aims to solve the technical problems existing in the prior art. To this end, the present invention provides a simplified numerical simulation method for the nonlinear semi-rigid node structure of steel structure beams and columns.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A simplified numerical simulation method for a nonlinear semi-rigid joint structure of a steel structure beam-column is provided, comprising the following steps:

[0008] Step S1, establishing a finite element solid model of a semi-rigid node based on ANSYS, and extracting the bending moment rotation curve at the node and the load displacement curve at the beam end in the finite element solid model;

[0009] Step S2, establishing an equivalent finite element simplified model based on the finite element solid model, and simulating the rotational capacity of the node through the COMBIN 39 unit in ANSYS;

[0010] Step S3, assigning the bending moment rotation curve at the node extracted from the finite element solid model in step S1 to the COMBIN39 unit, applying the same boundary conditions and loads to the simplified finite element model as those to the finite element solid model;

[0011] Step S4, comparing the load-displacement curves of the beam end of the finite element solid model and the simplified model;

[0012] Step S5, analyzing and verifying the obtained data;

[0013] Step S6: After verifying that the finite element simplified model is correct, the semi-rigid node is applied to the finite element simplified model of the frame structure, and loads are applied to obtain the internal force diagram of the frame structure after using the semi-rigid node. Then, according to the adjustment of the internal force diagram, the appropriate semi-rigid node is selected to complete the beam-column design.

[0014] In a preferred embodiment of the present invention, in step S1, by setting the actual bolt contact characteristics, fixed constraints are set at both ends of the column, vertical loads are applied to the beam ends, the bending moment rotation curve at the beam-column node is extracted, and the load-displacement curve at the beam end is extracted to provide data support and comparison reference for the subsequent finite element simplified model.

[0015] In a preferred embodiment of the present invention, in step S1, the bending moment rotation angle curve of the semi-rigid node can also be obtained through experimental research and theoretical calculation based on the semi-rigid node of the steel structure beam column.

[0016] In a preferred embodiment of the present invention, in step S2, the method for establishing the simplified finite element model is as follows:

[0017] Step S21, simulating the total deformation at the beam-column node based on the COMBIN 39 element in ANSYS;

[0018] In step S22, a beam-column truss system model is established based on the BEAM 189 unit in ANSYS, and a COMBIN 39 connection unit with a length of 0 is established at the beam-column connection point to obtain a simplified truss system model of the semi-rigid node of the steel structure beam-column. This truss system model is the simplified finite element model.

[0019] In a preferred embodiment of the present invention, in step S21, the total deformation at the beam-column node includes the tensile deformation of the bolts, the compressive deformation of the column web compression zone, the tensile deformation of the column web tension zone, the shear deformation of the column web shear zone, and the bending deformation of the column flange.

[0020] In a preferred embodiment of the present invention, in step S5, the obtained data is analyzed and verified, including:

[0021] By analyzing the obtained data, it can be seen that for the nonlinear semi-rigid joints of steel structure beams and columns, when the connection is subjected to load, the bolts, column webs and column flanges will all deform and affect the displacement of the beam ends. The load and displacement at the beam ends basically coincide, verifying that the nonlinear semi-rigid joints of steel structure beams and columns in the solid model can be simulated using the combination unit based on ANSYS.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This paper uses the ANSYS-based combination unit to simulate that when beams and columns are subjected to vertical and horizontal loads, the internal force distribution will be different from that of rigid connections and hinged connections, and there is no calculation formula for its internal force. It also verifies that solid elements can be simulated by the ANSYS-based combination unit, which greatly reduces the number of modeling grids and the complexity of contact settings, while ensuring the reliability and authenticity of the research. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0025] Figure 1 This is a flow chart of a simplified numerical simulation method for a nonlinear semi-rigid node structure of a steel structure beam-column provided by the present invention;

[0026] Figure 2 It is a schematic diagram of the finite element solid model provided by the present invention;

[0027] Figure 3It is a schematic diagram of the simplified finite element model of COMBIN 39 unit provided by the present invention;

[0028] Figure 4 is a simplified schematic diagram of a semi-rigid node provided by the present invention;

[0029] Figure 5 is the bending moment angle curve of the finite element solid model provided by the present invention;

[0030] Figure 6 This is a comparison chart of the beam end displacement results of the COMBIN 39 unit simplified finite element model and the finite element solid model provided by the present invention;

[0031] Figure 7 This is the bending moment diagram of the steel frame provided by the present invention when it is rigidly connected;

[0032] Figure 8 This is a bending moment diagram of a steel frame when a nonlinear semi-rigid node is applied, as provided by the present invention.

[0033] In the figure: ① end plate bending resistance; ② column flange bending resistance; ③ bolt tension resistance; ④ column web shear resistance; ⑤ column web tension resistance; ⑥ column web compression resistance. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] Please refer to the instruction manual Figure 1 , this embodiment provides a simplified numerical simulation method for nonlinear semi-rigid node structures of steel structure beams and columns, including the following steps:.

[0036] Step S1: Establish a finite element solid model of the semi-rigid node based on ANSYS, as shown in the attached figure. Figure 2 As shown in the figure, the bending moment angle curve at the node in the finite element solid model is extracted (see the attached figure). Figure 5 as shown) and the load displacement curve at the beam end (see the appendix of the manual Figure 6 During implementation, actual bolt contact characteristics were set in the finite element solid model, fixed constraints were set at both ends of the column, vertical loads were applied to the beam ends, the moment-rotation curves at the beam-column joints were extracted, and the load-displacement curves at the beam ends were extracted to provide data support and comparison reference for the subsequent simplified finite element model.

[0037] Step S2: Establish the finite element model as shown in the attached figure. Figure 3The equivalent simplified finite element model is shown, and the rotation capacity of the node is simulated by COMBIN 39 element in ANSYS;

[0038] Specifically, the method for establishing the simplified finite element model in this embodiment is as follows:

[0039] Step S21, simulating the tensile deformation of bolts at the beam-column joint, the compressive deformation of the column web compression zone, the tensile deformation of the column web tension zone, the shear deformation of the column web shear zone, and the bending deformation of the column flange in the finite element solid model based on the COMBIN 39 unit in ANSYS;

[0040] Step S22, based on the BEAM 189 unit in ANSYS, a beam-column bar system model is established, and a COMBIN 39 connection unit with a length of 0 is established at the beam-column connection point to obtain a simplified bar system model of the semi-rigid node of the steel structure beam-column. This bar system model is a simplified finite element model, as shown in the attached figure. Figure 4 shown.

[0041] The simplified principle of applying the COMBIN 39 element in this embodiment is: beam elements are used instead of solid elements to simulate beams and columns, and COMBIN 39 elements are used to replace the total deformation of the tensile deformation of the bolts at the beam-column node in the solid model, the compressive deformation of the column web compression zone, the tensile deformation of the column web tension zone, the shear deformation of the column web shear zone, and the bending deformation of the column flange.

[0042] Step S3, assigning the bending moment rotation curve at the node extracted from the finite element solid model in step S1 to the COMBIN39 unit, applying the same boundary conditions and loads to the simplified finite element model as those to the finite element solid model;

[0043] Step S4, compare the load displacement curves of the beam end of the finite element solid model and the simplified model, as shown in the attached figure. Figure 6 As shown;

[0044] Step S5, analyzing and verifying the obtained data, including:

[0045] By analyzing the obtained data, it can be seen that for the nonlinear semi-rigid joints of steel structure beams and columns, when the connection is subjected to load, the bolts, column webs and column flanges will all deform and affect the displacement of the beam ends. The load and displacement at the beam ends basically coincide, verifying that the nonlinear semi-rigid joints of steel structure beams and columns in the solid model can be simulated using the combination unit based on ANSYS.

[0046] By the attached Figure 6It can be seen that the displacement curve of the beam end has obvious nonlinear characteristics, and the load-displacement curves of the beam end of the finite element solid model and the finite element simplified model are basically consistent, indicating that the calculation results of the finite element solid model and the finite element simplified model are consistent, verifying that the tensile deformation of the bolts in the solid model, the compressive deformation of the column web compression zone, the tensile deformation of the column web tension zone, the shear deformation of the column web shear zone, and the bending deformation of the column flange can be simplified simulated by the combination unit based on ANSYS, and the internal force situation after applying the semi-rigid node can be obtained for use in the design; and it is verified that the solid unit can be simulated by the combination unit based on ANSYS, which greatly reduces the number of modeling grids and the complexity of contact settings, while ensuring the reliability and authenticity of the research.

[0047] Step S6: After verifying that the finite element simplified model is correct, the node (semi-rigid node of the steel structure beam column) is applied to the finite element simplified model of the frame structure, and load is applied to obtain the internal force diagram of the frame structure after using the semi-rigid node, as shown in the attached figure. Figure 8 As shown, the appropriate semi-rigid nodes are then selected based on the adjustment of the internal force diagram to complete the beam-column design. In specific implementation, the selection of appropriate semi-rigid nodes includes: beam-column size, connection form (end plate, top and bottom angle steel, etc.), bolt diameter grade, and layout position.

[0048] When the simplified finite element model is applied to the design of the entire building, the simplified finite element model is established based on the BEAM 189 unit in ANSYS to establish a simplified structural model of the beam-column system when it is rigidly connected. The load can be applied to obtain the following Figure 7 The internal force diagram of the structure when rigidly connected is shown in the figure. Then, based on the internal force diagram of the structure when rigidly connected, appropriate semi-rigid nodes are selected. Subsequently, loads are applied to the simplified finite element model, and the following is obtained: Figure 8 The internal force diagram after using semi-rigid nodes is shown. In this way, appropriate semi-rigid nodes are selected according to the adjustment of the internal force diagram to complete the beam-column design.

[0049] It is worth noting that: in other embodiments, the bending moment rotation angle curve of the semi-rigid node can also be obtained through experimental research and theoretical calculation based on the semi-rigid node of the steel structure beam column.

[0050] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A simplified numerical simulation method for nonlinear semi-rigid joint structures of steel beams and columns, characterized by: The following steps are involved: Step S1, establishing a finite element solid model of a semi-rigid node based on ANSYS, and extracting the bending moment angle curve at the node and the load displacement curve at the beam end in the finite element solid model; Step S2: Establish an equivalent simplified finite element model based on the finite element solid model, and simulate the rotation ability of the node using the COMBIN39 unit in ANSYS. The method for establishing the simplified finite element model is as follows: Step S21, simulating the total deformation at the beam-column node based on the COMBIN 39 element in ANSYS, where the total deformation at the beam-column node includes the tensile deformation of the bolts, the compressive deformation of the column web compression zone, the tensile deformation of the column web tension zone, the shear deformation of the column web shear zone, and the bending deformation of the column flange; Step S22: establishing a beam-column truss system model based on the BEAM 189 element in ANSYS, and establishing a COMBIN 39 connection element with a length of 0 at the beam-column connection point to obtain a simplified truss system model of the semi-rigid joint of the steel structure beam and column. This truss system model is the simplified finite element model. Step S3, assigning the bending moment rotation curve at the node extracted from the finite element solid model in step S1 to the COMBIN39 unit, applying the same boundary conditions and loads to the simplified finite element model as those to the finite element solid model; Step S4, comparing the load-displacement curves of the beam end of the finite element solid model and the simplified model; Step S5, analyzing and verifying the obtained data; Step S6: After verifying that the finite element simplified model is correct, the semi-rigid node is applied to the finite element simplified model of the frame structure, and loads are applied to obtain the internal force diagram of the frame structure after using the semi-rigid node. Then, according to the adjustment of the internal force diagram, the appropriate semi-rigid node is selected to complete the beam-column design.

2. The simplified numerical simulation method for nonlinear semi-rigid joint structures of steel beams and columns according to claim 1 is characterized by: In step S1, by setting the actual bolt contact characteristics, fixed constraints are set at both ends of the column, vertical loads are applied to the beam ends, the bending moment rotation curve at the beam-column node is extracted, and the load-displacement curve at the beam end is extracted to provide data support and comparison reference for the subsequent finite element simplified model.

3. The simplified numerical simulation method for nonlinear semi-rigid joint structures of steel beams and columns according to claim 1 is characterized by: In step S1, the bending moment rotation angle curve of the semi-rigid node can also be obtained through experimental research and theoretical calculation based on the semi-rigid node of the steel structure beam column.

4. The simplified numerical simulation method for nonlinear semi-rigid joint structures of steel beams and columns according to claim 1, characterized in that: In step S5, the obtained data is analyzed and verified, including: By analyzing the obtained data, it can be seen that for the nonlinear semi-rigid joints of steel structure beams and columns, when the connection is subjected to load, the bolts, column webs and column flanges will all deform and affect the displacement of the beam ends. The load and displacement at the beam ends basically coincide, verifying that the nonlinear semi-rigid joints of steel structure beams and columns in the solid model can be simulated using the combination unit based on ANSYS.

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