A method and system for defining local axes of components of a special-shaped space lattice shell structure

Abstract

The present invention discloses a method and system for defining the local axis of a component of a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper, which belongs to the field of spatial structure design technology. Based on the principle that the weak axis (i.e., the 2nd axis) of the component section is perpendicular to the outer skin of the building, the Grasshopper plug-in of the Rhino platform is used to batch extract the local axis direction vectors of the components and import them into the analysis model. The local axis of each structural component is set efficiently and accurately, which improves the efficiency and accuracy of the structural design.

Description

Technical Field

[0001] The present invention belongs to the technical field of spatial structure design, and more specifically, relates to a method and system for defining local axes of components of a special-shaped spatial lattice shell structure composed of rectangular components based on Grasshopper. Background Art

[0002] In recent years, with the development of national economy and science and technology and the people's growing material and cultural needs, owners and architects have increasingly tended to control the appearance of buildings in a curved and special way to highlight the uniqueness and landmark of the building. Various types of special-shaped curved surface skins have become the mainstream of the construction industry and are widely used in transportation, sports stadiums, cultural and entertainment venues, commercial venues and various exhibition buildings. Space gridshell structure is a structural form with simple structure, clear force transmission path and good architectural aesthetics in space structure, which is favored by architects and structural engineers. Due to the performance limitations of structural materials (aluminum alloy structure and glued wood structure can only use rectangular cross-section components) and the structural force limitations caused by the building form (special-shaped space gridshell structure is often mainly subjected to bending force, and the circular cross-section has poor bending stiffness), rectangular components are often the only choice for space gridshell structure.

[0003] Rectangular cross-sections are different from circular cross-sections in that the bending and shear properties of the cross-sections with strong and weak symmetry axes are inconsistent. In the finite element analysis software, there is a large difference between the local axis set by the program by default and the local axis required for the actual design. It is necessary to manually set the local axis of the component in the analysis software to ensure the consistency between the structural analysis and the actual situation, thereby ensuring the safety and economy of the structure. In the past, designers often ignored the impact of this local axis difference and considered this difference in the form of controlling the stress ratio of the component, which has an impact on the safety and economy of the structure; or manually modified the local axis of the component in the finite element analysis software, but there are often thousands of components in a project. This local axis specification mode is extremely slow, inefficient, and prone to setting errors. Therefore, it is necessary to study a fast and accurate way to define the local axis of the component for the irregular space lattice shell structure composed of rectangular components. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention proposes a component local axis definition method and system for a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper, which can quickly and accurately realize the component local axis definition method for the special-shaped space lattice shell structure composed of rectangular components.

[0005] To achieve the above object, according to one aspect of the present invention, a method for defining local axes of components of a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper is provided, comprising:

[0006] Establish component axis model in Rhino according to the outer skin and mesh size;

[0007] Extract the midpoint and midpoint coordinates of each component axis in the component axis model established in Rhino;

[0008] Offset the building's exterior skin inward or outward by a preset distance to form an offset skin;

[0009] Find the point in the offset skin that is closest to the middle of the component axis, i.e. the vertical point;

[0010] Connect the midpoint of the component axis and the perpendicular point of the component axis to form a vector as the component local axis direction vector;

[0011] Import the axis model into the finite element analysis software to form a line unit model;

[0012] Exporting line element geometric information in the line element model, wherein the exported geometric information includes component number, line element start point and end point coordinates;

[0013] Calculate the coordinates of the midpoint of the component with the corresponding component number according to the derived coordinates of the starting and ending points of the line unit;

[0014] According to the principle of consistent matching of component midpoint coordinates, the component number in the line element model is matched with the component local axis direction vector;

[0015] Import the matching component local axis direction vectors into the finite element analysis software.

[0016] In some optional embodiments, the vector formed by the midpoint of the axis of the connecting component and the perpendicular point of the axis of the component is the direction vector of the local 1-2 plane of the component relative to the overall coordinate axis. At this time, an axis midpoint coordinate in the axis model can correspond to a local axis direction vector of the component.

[0017] In some optional embodiments, the preset distance is 1 / 2 of the height of the component cross section.

[0018] In some optional implementation schemes, the establishment of the component axis model, the extraction of the midpoint of the component axis and the midpoint coordinates, the offset of the building outer skin, the acquisition of the vertical point and the formation of the component local axis direction vector are all achieved through Grasshopper.

[0019] According to another aspect of the present invention, a component local axis definition system for a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper is provided, comprising:

[0020] The axis model building module is used to build the component axis model in Rhino according to the outer skin and mesh size;

[0021] Coordinate extraction module, used to extract the midpoint and midpoint coordinates of each component axis in the component axis model established in Rhino;

[0022] An offset module is used to offset the building's exterior skin inward or outward by a preset distance to form an offset skin;

[0023] The vertical point acquisition module is used to find the point in the offset skin that is closest to the middle of the component axis, i.e. the vertical point;

[0024] A local axis direction vector acquisition module is used to connect the midpoint of the component axis and the vertical point of the component axis to form a vector as the local axis direction vector of the component;

[0025] A line unit model forming module is used to import the axis model into the finite element analysis software to form a line unit model;

[0026] A line unit information export module is used to export line unit geometric information in the line unit model, wherein the exported geometric information includes component number, line unit start point and end point coordinates;

[0027] A calculation module, used to calculate the coordinates of the midpoint of the component with the corresponding component number according to the derived coordinates of the starting point and the end point of the line unit;

[0028] A matching module is used to match the component number in the line element model with the component local axis direction vector according to the principle of consistent matching of the component midpoint coordinates;

[0029] The finite element import module is used to import the matching component local axis direction vectors into the finite element analysis software.

[0030] In some optional embodiments, the vector formed by the midpoint of the axis of the connecting component and the perpendicular point of the axis of the component is the direction vector of the local 1-2 plane of the component relative to the overall coordinate axis. At this time, an axis midpoint coordinate in the axis model can correspond to a local axis direction vector of the component.

[0031] In some optional embodiments, the preset distance is 1 / 2 of the height of the component cross section.

[0032] In some optional implementation schemes, the establishment of the component axis model, the extraction of the midpoint of the component axis and the midpoint coordinates, the offset of the building outer skin, the acquisition of the vertical point and the formation of the component local axis direction vector are all achieved through Grasshopper.

[0033] According to another aspect of the present invention, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of any one of the above methods are implemented.

[0034] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0035] The present invention proposes a method for defining the local axis of a component of a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper. Based on the principle that the weak axis of the component section is perpendicular to the outer skin of the building, the Grasshopper plug-in of the Rhino platform is used to batch extract the local axis direction vectors of the components and import them into the analysis model. The local axis of each structural component is set efficiently and accurately, which improves the efficiency and accuracy of structural design. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of a method flow provided by an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of a typical component of a Rhino model provided by an embodiment of the present invention;

[0038] Figure 3 It is a default local axis in a finite element analysis software provided by an embodiment of the present invention;

[0039] Figure 4 It is a schematic diagram of component stretching using a default local axis provided by an embodiment of the present invention;

[0040] Figure 5 is a modified local axis in a finite element analysis software provided by an embodiment of the present invention;

[0041] Figure 6 It is a schematic diagram of a component stretching in a modified local axis case provided by an embodiment of the present invention, that is, a schematic diagram of the actual construction completion effect;

[0042] In the figure, 1-component axis, 2-axis midpoint, 3-building outer skin, 4-offset skin, 5-vertical point, 6-local axis direction vector. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0044] like Figure 1 As shown, the present invention provides a method for defining the local axis of a component of a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper, and the specific implementation steps are as follows:

[0045] 1) Create a component axis model 1 in Rhino based on the outer skin 3 and grid size provided by the architect, such as Figure 2 As shown;

[0046] In step 1), the axis is introduced into Grasshopper using the Curve command in Grasshopper, and the building outer skin is introduced into Grasshopper using the Brep command in Grasshopper.

[0047] 2) Use the Curve Middle command in Grasshopper to extract the midpoint 2 and midpoint coordinates of each component axis;

[0048] 3) Using the Offset Surface command in Grasshopper, the building outer skin 3 is offset inward or outward by a preset distance to form an offset skin 4;

[0049] The preset distance of the offset can be determined according to actual needs, and is recommended but not limited to 1 / 2 of the component section height.

[0050] 4) Use the Brep Closest Point command in Grasshopper to find the point in the offset skin that is closest to the middle of the component axis, i.e., vertical point 5;

[0051] 5) Use the Vector 2Pt command in Grasshopper to connect the midpoint of the component axis and its vertical point to form a vector, which is the direction vector 6 of the local 1-2 plane of the component relative to the global coordinate axis. At this time, the coordinate of an axis midpoint in the axis model can correspond to a component local axis direction vector;

[0052] 6) Import the axis model into the finite element analysis software to form a line unit model;

[0053] 7) exporting the line element geometry information in the line element model described in 6) to Excel, including the component number, start point and end point coordinates;

[0054] 8) Calculate the coordinates of the midpoint of the component with the corresponding component number in Excel based on the derived coordinates of the starting and ending points of the line unit;

[0055] 9) According to the principle of consistent matching of component midpoint coordinates, use the VLOOKUP function in Excel to match the component number in the line element model described in 6) with the component local axis direction vector;

[0056] 10) Import the matching component local axis direction vector into the finite element analysis software.

[0057] Figure 3 It is the default local axis in the finite element analysis software. The default local axis 1 is along the component direction. The default local 2-axis and 3-axis are determined according to the relationship between the local 1-axis and the global coordinate Z-axis. The local 1-2 plane is vertical, that is, parallel to the global Z-axis. After determining the 1-2 plane, the local 2-axis is determined by being perpendicular to the local 1-axis, and the local 3-axis is determined by being perpendicular to the 1-2 plane. Figure 4 This is a schematic diagram of the component stretching with the default local axis. Figure 4 It can be seen that the rotation angles of the components are inconsistent and do not match the actual situation. When making manual adjustments, each component needs multiple attempts, which results in a large workload and low precision.

[0058] Figure 5 To adjust the local axis modified in the finite element analysis software according to the above method, Figure 6 This is a schematic diagram of the component stretching under the modified local axis condition, which is a schematic diagram of the actual construction completion effect. After the adjustment, the flange plates and nodes of each component are basically parallel, achieving the expected effect of the architectural design.

[0059] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0060] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for defining the local axis of a component of a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper, characterized in that: include: According to the outer skin and mesh size, the component axis model is established in Rhino. The axis is introduced into Grasshopper using the Curve command in Grasshopper. The outer skin of the building is introduced into Grasshopper using the Brep command in Grasshopper. Extract the midpoint and midpoint coordinates of each component axis in the component axis model established in Rhino; Offset the building's exterior skin inward or outward by a preset distance to form an offset skin; Find the point in the offset skin that is closest to the middle of the component axis, i.e. the vertical point; Connect the midpoint of the component axis and the perpendicular point of the component axis to form a vector as the component local axis direction vector; Import the axis model into the finite element analysis software to form a line unit model; Exporting line element geometric information in the line element model, wherein the exported geometric information includes component number, line element start point and end point coordinates; Calculate the coordinates of the midpoint of the component with the corresponding component number according to the derived coordinates of the starting and ending points of the line unit; According to the principle of consistent matching of component midpoint coordinates, the component number in the line element model is matched with the component local axis direction vector; Import the matching component local axis direction vectors into the finite element analysis software.

2. The method according to claim 1, characterized in that The vector formed by connecting the midpoint of the component axis and the vertical point of the component axis is the direction vector of the local 1-2 plane of the component relative to the global coordinate axis. At this time, the coordinate of an axis midpoint in the axis model can correspond to a local axis direction vector of the component.

3. The method according to claim 1, characterized in that The preset distance is 1 / 2 of the component section height.

4. The method according to any one of claims 1 to 3, characterized in that: The establishment of the component axis model, the extraction of the midpoint and midpoint coordinates of the component axis, the offset of the building outer skin, the acquisition of the vertical point and the formation of the component local axis direction vector are all achieved through Grasshopper.

5. A component local axis definition system for a special-shaped space lattice shell structure composed of rectangular components based on Grasshopper, characterized in that: include: The axis model building module is used to build the component axis model in Rhino according to the outer skin and mesh size, use the Curve command in Grasshopper to import the axis into Grasshopper, and use the Brep command in Grasshopper to import the building outer skin into Grasshopper; Coordinate extraction module, used to extract the midpoint and midpoint coordinates of each component axis in the component axis model established in Rhino; An offset module is used to offset the building's exterior skin inward or outward by a preset distance to form an offset skin; The vertical point acquisition module is used to find the point in the offset skin that is closest to the middle of the component axis, namely the vertical point; A local axis direction vector acquisition module is used to connect the midpoint of the component axis and the vertical point of the component axis to form a vector as the local axis direction vector of the component; A line unit model forming module is used to import the axis model into the finite element analysis software to form a line unit model; A line unit information export module is used to export line unit geometric information in the line unit model, wherein the exported geometric information includes component number, line unit start point and end point coordinates; A calculation module, used to calculate the coordinates of the midpoint of the component with the corresponding component number according to the derived coordinates of the starting point and the end point of the line unit; A matching module is used to match the component number in the line element model with the component local axis direction vector according to the principle of consistent matching of the component midpoint coordinates; The finite element import module is used to import the matching component local axis direction vectors into the finite element analysis software.

6. The system according to claim 5, characterized in that The vector formed by connecting the midpoint of the component axis and the vertical point of the component axis is the direction vector of the local 1-2 plane of the component relative to the global coordinate axis. At this time, the coordinate of an axis midpoint in the axis model can correspond to a local axis direction vector of the component.

7. The system according to claim 5, characterized in that The preset distance is 1 / 2 of the component section height.

8. The system according to any one of claims 5 to 7, characterized in that: The establishment of the component axis model, the extraction of the midpoint and midpoint coordinates of the component axis, the offset of the building outer skin, the acquisition of the vertical point and the formation of the component local axis direction vector are all achieved through Grasshopper.

9. A computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the method according to any one of claims 1 to 4 when executed by a processor.

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