Open-web truss structure design method based on single-layer cable net deformation form

Abstract

The invention discloses an open-web truss structure design method based on a single-layer cable net deformation form, and relates to the field of building design. The open-web truss structure design method based on the single-layer cable net deformation form comprises the following steps that a building space curved surface is projected to an xoy plane, and a projection line of a building outer contour line on the xoy plane is obtained; designing an initial cable net structure model based on the projection line of the outer contour line of the building in combination with building modeling requirements; finite element software is adopted to simulate the deformation form and deformation data of the initial cable net structure model under real load and real boundary conditions; extracting a displacement result of nodes of the initial cable net structure model, and performing scaling processing by combining the displacement result with the actual size of the building to obtain an optimal cable net structure matched with the actual shape of the building; and modifying the optimal cable net structure into an open-web truss structure. The open-web truss structure design method based on the deformation form of the single-layer cable net solves the problem of shear design of vertical rods in open-web truss design, and has the advantages of clear mechanics concept, simplicity in operation, low design difficulty and time and cost saving.

Description

Technical Field

[0001] This application relates to the field of architectural design, and more specifically, to a design method for a hollow truss structure based on the deformation morphology of a single-layer cable net. Background Technology

[0002] Hollow trusses have advantages such as a simple and elegant appearance, high space utilization, easy pipeline layout, and fewer node types, which can meet the spatial requirements of large-span buildings and enhance the architectural effect. However, hollow trusses also have disadvantages such as relatively weak overall stiffness, low redundancy, complex design, large material consumption, and shear stress on vertical members. These characteristics mean that hollow trusses need to be selected and weighed according to the specific engineering characteristics in practical applications.

[0003] The vertical web members of a hollow truss are subject to large shear forces, making the design of hollow trusses difficult, requiring a large amount of material, and limiting the applicable span. Since this problem is an inherent stress problem of the structure, existing technologies cannot solve it. Summary of the Invention

[0004] The purpose of this application is to provide a design method for hollow truss structures based on the deformation morphology of a single-layer cable net. The hollow truss structure obtained by the form-finding method based on the deformation morphology of a single-layer cable net structure utilizes the mechanical property that cable elements can only withstand tensile stress to obtain a structural surface with a very small bending moment ratio. The hollow truss designed based on this structural surface can ensure that the upper and lower chords of the truss are in a state of tension or compression under the action of external forces, thereby effectively solving the design problem of shear stress on vertical members in the design of hollow trusses. This method has the advantages of clear mechanical concepts, simple operation, low design difficulty, and saving time and cost.

[0005] This application is implemented as follows: This application provides a design method for hollow truss structures based on the deformation morphology of a single-layer cable net, including the following steps: Project the architectural space surface onto the xoy plane to obtain the projection line of the building's outer contour on the xoy plane; The initial cable net structure model was designed based on the projection lines of the building's outer contour and the architectural design requirements. The deformation morphology and deformation data of the initial cable net structure model under real load and real boundary conditions were simulated using finite element software. The displacement results of the nodes of the initial cable net structure model are extracted and scaled together with the actual building dimensions to obtain the optimal cable net structure that matches the actual building shape. The optimal cable net structure was modified into a hollow truss structure.

[0006] In some alternative implementations, an initial cable net structure model is designed after the projection lines of the building's outer contour are combined with the building's styling requirements to create a grid.

[0007] In some alternative implementations, when using finite element software to simulate the deformation morphology and deformation data of the initial cable net structure model under real loads and real boundary conditions, real boundary conditions are set for the outer contour nodes of the initial cable net structure model, and real loads are applied to the internal nodes.

[0008] In some alternative implementations, when finite element software is used to simulate the deformation morphology and deformation data of the initial cable net structure model under real loads and real boundary conditions, the deformation morphology of the initial cable net structure model under geometric nonlinearity and large displacement conditions is obtained.

[0009] In some optional implementations, extracting the displacement results of the nodes of the initial cable net structure model includes extracting the deformation morphology and deformation data of the nodes of the initial cable net structure model, and scaling them in combination with the actual building dimensions to obtain the optimal structural morphology that matches the actual building shape.

[0010] In some alternative implementations, when the optimal cable net structure is modified into a hollow truss structure, the upper and lower chords of the hollow truss structure adopt cross-shaped box sections or H-shaped sections.

[0011] In some alternative implementations, when the optimal cable net structure is modified into a hollow truss structure, the vertical members of the hollow truss structure are made of round tubes.

[0012] In some alternative implementations, when the optimal cable net structure is modified into a hollow truss structure, the hollow truss structure is connected to the concrete frame columns and concrete frame beams via spherical hinge supports.

[0013] The beneficial effects of this application are as follows: The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net provided by this application includes the following steps: projecting the building's spatial curved surface onto the xoy plane to obtain the projection line of the building's outer contour line on the xoy plane; designing an initial cable net structure model based on the projection line of the building's outer contour line and the building's styling requirements; using finite element software to simulate the deformation morphology and deformation data of the initial cable net structure model under real loads and real boundary conditions; extracting the displacement results of the nodes of the initial cable net structure model and scaling them in combination with the actual building dimensions to obtain the optimal cable net structure that matches the actual building shape; and modifying the optimal cable net structure into a hollow truss structure. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net provided by this application obtains a hollow truss structure based on the cable net structure design through a structural form-finding method. It utilizes the mechanical property that cable elements can only withstand tensile stress to reduce the vertical shear force of the structure, solving the design problem of vertical members being subjected to shear in hollow truss design. It has the advantages of clear mechanical concepts, simple operation, low design difficulty, and saving time and costs. Attached Figure Description

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 A flowchart illustrating the design method for a hollow truss structure based on the deformation morphology of a single-layer cable net, provided in an embodiment of this application. Figure 2 This is a schematic diagram of the initial cable net structure model designed after grid division based on the projection lines of the building's outer contour and the building's shape requirements in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application. Figure 3 The hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application uses finite element software to simulate the initial cable net structure model and the deformation data under real load and boundary conditions; Figure 4 The first-view structural diagram of the hollow truss structure modified from the optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application. Figure 5 A partial structural diagram showing the modification of the optimal cable net structure into a hollow truss structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application. Figure 6 A schematic diagram of the second perspective of modifying the optimal cable net structure into a hollow truss structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application. Figure 7 The optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application is modified to the axial force of the hollow truss structure under constant load. Figure 8 The optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application is modified to the structural bending moment of the hollow truss structure under constant load. Figure 9 The optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application is modified to the shear force of the vertical web members of the hollow truss structure under dead load. Figure 10 The optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application is modified to the bending moment of the vertical web members of the hollow truss structure under dead load. Figure 11 The optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application is modified to the axial force of the hollow truss structure under wind load. Figure 12 The optimal cable net structure in the hollow truss structure design method based on the deformation morphology of a single-layer cable net provided in the embodiments of this application is modified to the structural bending moment of the hollow truss structure under wind load.

[0016] In the figure: 1. Projection line of the building outline on the xoy plane; 2. Initial cable net structure model; 3. Open truss structure; 31. Top chord; 32. Bottom chord; 33. Vertical member; 4. Steel-concrete frame column; 5. Steel-concrete frame beam. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0018] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] The following describes in further detail the features and performance of the hollow truss structure design method based on the deformation morphology of a single-layer cable net, with reference to the embodiments.

[0020] like Figure 1 As shown in the figure, this application provides a design method for a hollow truss structure based on the deformation morphology of a single-layer cable net, including the following steps: Step S1: Project the architectural space surface onto the xoy plane to obtain the projection line 1 of the architectural outline on the xoy plane; Step S2: Based on the projection lines 1 of the building's outer contour and the architectural design requirements, a mesh is generated, and then the initial cable net structure model 2 is designed, as follows: Figure 2 As shown; Step S3: Simulate the initial cable net structure model using finite element software. Set realistic boundary conditions for the outer contour nodes of the initial cable net structure model and apply realistic loads to the internal nodes to obtain the deformation morphology and deformation data of the initial cable net structure model considering geometric nonlinearity and large displacement conditions, such as... Figure 3 As shown; Step S4: Extract the displacement results of each node of the initial cable net structure model and scale them together with the actual building dimensions to obtain the optimal cable net structure that matches the actual building shape; wherein, the scaling process takes into account the reasonable sag-to-span ratio of the structure under stress. Step S5: Modify the optimal cable net structure to a hollow truss structure 3, such as... Figure 4 , Figure 5 and Figure 6 As shown; in this structure, the upper chord 31 and lower chord 32 of the open truss structure 3 adopt a cross-shaped box section or an H-shaped section, and the vertical members 33 of the open truss structure are circular tubes. The open truss structure 3 is connected to the steel-concrete frame column 4 and the steel-concrete frame beam 5 through spherical hinge supports. The internal forces of the upper chord 31 and lower chord 32 of the open truss structure are all tension or compression, and there is no situation where the upper chord 31 is under compression and the lower chord 32 is under tension.

[0021] The simulation was performed after modifying the optimal cable net structure to a hollow truss structure. Figure 7 , Figure 8 , Figure 9 , Figure 10 As shown, the axial force of the modified hollow truss structure with optimal cable net structure is basically 2000-4000KN under gravity load, and the bending moment is 20-60KN. The axial force is about 100 times the bending moment. The modified hollow truss structure with optimal cable net structure mainly bears the axial force and bears very small bending moment. At the same time, it can be seen from the shear force of the vertical web members that the maximum shear force of the vertical web members is 65KN, which accounts for less than 3% of the axial force of the upper and lower chords. Meanwhile, the bending moment is only 2KN·m, which is extremely small. Based on the above analysis, the modified hollow truss structure with optimal cable net structure is a form-effect structure, that is, it mainly bears the axial force.

[0022] like Figure 11 and Figure 12 As shown, when the optimal cable net structure is modified into a hollow truss structure, under wind load, the members are basically under compression, with a pressure of about 2000-2800KN. The stress is very uniform, the bending moment is about 20-40KN·m, and the axial force is 70-100 times the bending moment. This indicates that under wind load, the optimal cable net structure modified into a hollow truss structure also mainly bears axial force and bears a very small bending moment.

[0023] The beneficial effects of the open-web truss structure design method based on the deformation morphology of a single-layer cable net provided in this application are: 1. By optimizing the overall shape of the initial cable net structure model to utilize the mechanical property that cable elements can only withstand tensile stress, the initial cable net structure model can obtain the optimal structural form in the first equilibrium state where only tensile stress exists in the internal forces of the structure, thus ensuring the accuracy of the form-finding results. II. The hollow truss structure modified based on the optimal cable net structure after form finding has a very small overall bending moment under self-weight, dead load and live load, and mainly bears axial force. The internal forces of the upper and lower chords of the hollow truss are all tensile, and there is no situation where the upper chord is compressed and the lower chord is tensile. As a result, the shear force of the vertical members is very small. Furthermore, the hollow truss structure modified based on the optimal cable net structure after form finding forms forms an arch shape under the action of reverse load, i.e. wind load. Both the upper and lower chords are under compression. In addition, the bending stiffness of the structure itself makes the structure able to resist the action of wind load very well.

[0024] III. Based on the optimal cable net structure modified after form finding, the open truss structure is divided according to the building needs and is adapted to the building shape. The structural components can be exposed, and the building does not need to design an additional suspended ceiling, saving building costs. Moreover, pipelines can cross the open truss, which is beneficial to the control of the building's net height. Fourth, the mechanical concept of the hollow truss structure modified based on the optimal cable net structure after form finding is clear, the operation is simple, and the structural design difficulty is greatly reduced.

[0025] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A design method for a hollow truss structure based on the deformation morphology of a single-layer cable net, characterized in that, Includes the following steps: Project the architectural space surface onto the xoy plane to obtain the projection line of the building's outer contour on the xoy plane; The initial cable net structure model was designed based on the projection lines of the building's outer contour and the architectural design requirements. The deformation morphology and deformation data of the initial cable net structure model under real load and real boundary conditions were simulated using finite element software. The displacement results of the nodes of the initial cable net structure model are extracted and scaled together with the actual building dimensions to obtain the optimal cable net structure that matches the actual building shape. The optimal cable net structure was modified into a hollow truss structure.

2. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, The initial cable net structure model is designed after the projection lines of the building's outer contour are combined with the building's shape requirements to divide the grid.

3. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, When using finite element software to simulate the deformation morphology and deformation data of the initial cable net structure model under real load and real boundary conditions, real boundary conditions are set for the outer contour nodes of the initial cable net structure model, and real loads are applied to the internal nodes.

4. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, When finite element software is used to simulate the deformation morphology and deformation data of the initial cable net structure model under real load and real boundary conditions, the deformation morphology of the initial cable net structure model under geometric nonlinearity and large displacement conditions is obtained.

5. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, Extracting the displacement results of the nodes of the initial cable net structure model includes extracting the deformation shape and deformation data of the nodes of the initial cable net structure model, and scaling them in combination with the actual building dimensions to obtain the optimal structural shape that matches the actual building shape.

6. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, When the optimal cable net structure is modified into a hollow truss structure, the upper and lower chords of the hollow truss structure adopt cross-shaped box sections or H-shaped sections.

7. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, When modifying the optimal cable net structure into a hollow truss structure, the vertical members of the hollow truss structure are made of round tubes.

8. The design method for a hollow truss structure based on the deformation morphology of a single-layer cable net according to claim 1, characterized in that, When the optimal cable net structure is modified into a hollow truss structure, the hollow truss structure is connected to the concrete frame columns and concrete frame beams through spherical hinge supports.

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