A spatial circular pipe intersecting node parameterized modeling method based on layer information

Abstract

The application discloses a kind of space pipe intersecting node parameterization modeling methods based on layer information, comprising the following steps: S1 geometric model preparation;S2 layer information extraction;S3. uniformity of bar length;S4. geometric model generation;S5. mutual boolean operation;S6. result output integration.The application is more operable, and it is favorable to improve work efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of large-span space structure node modeling, and particularly relates to a parameterized modeling method for a space circular pipe intersecting node based on layer information. BACKGROUND

[0002] A large-span space structure is a new type of building structure capable of realizing large space and complex form, and has the characteristics of lightness, beauty and creativity, and has high bearing capacity and adaptability, and can meet various functional requirements, and is widely used in modern buildings. The node design of the large-span space structure is a key link for structural safety and construction feasibility.

[0003] The complex node usually has the following characteristics: 1) complex spatial geometry: multiple bars intersect at the node, and the spatial geometric position relationship between the bars is complex; 2) complex stress characteristics: the node bears multi-directional load, and the stress distribution is uneven, and there is also mutual force between the local nodes due to the intersection on the space; 3) complex construction and installation: the node manufacturing and installation precision is high, and the construction process is complex.

[0004] The traditional node design method mainly relies on empirical formula and manual calculation, and this method is difficult to meet the form innovation and fine design requirements of the complex node. The parameterized modeling of the space circular pipe intersecting node can effectively improve the design efficiency, which can comprehensively consider the geometric and mechanical properties of the node, realize the generation of the node model and the integrated design of the construction process, and realize the collaborative optimization of the node design and the overall structure. Therefore, how to realize efficient and accurate modeling of the complex space circular pipe intersecting node is a key problem that needs to be solved by technical personnel at present. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a parameterized modeling method for a space circular pipe intersecting node based on layer information, which can realize efficient and accurate modeling of the complex space circular pipe intersecting node.

[0006] To solve the above technical problems, the technical solutions adopted by the present application are as follows.

[0007] A parameterized modeling method for a space circular pipe intersecting node based on layer information, comprising the following steps:

[0008] S1. Geometric model preparation: extracting the node and the connected bar line model from the overall structure model, and naming the layers in a fixed format according to the bar section specifications, and merging the same specification bars into the same layer;

[0009] S2. Layer information extraction: analyzing the layer name to decompose the corresponding steel pipe outer diameter and wall thickness of each bar, and distinguishing the main pipe and the branch pipe to input the corresponding center line of each bar;

[0010] S3. Rod length uniform: take the branch intersection as the center of the sphere, and establish a sphere with a specified length as the radius. Cut each rod and select the adjacent side of the intersection point;

[0011] S4. Geometric model generation: connect the two straight lines of the main pipe into a straight line, then select the modeling method to model;

[0012] S5. Mutual Boolean operation: the intersection relationship between the rods is processed by Boolean operation to obtain the intersection nodes that do not intersect each other;

[0013] S6. Result output integration.

[0014] Preferably, all modeling length units in step S1 are mm, and the layer naming format is: PDxt, wherein P represents steel pipe; D is the outer diameter of the steel pipe; t is the wall thickness of the steel pipe; and x is a connection character.

[0015] Preferably, in step S2, the steel pipe outer diameter and wall thickness corresponding to each rod are decomposed by analyzing the layer name. Specifically, the line model is imported into Rhino, and the information of the connected rod of the node is automatically read, including but not limited to: geometric shape, spatial position, topological relationship and layer information; then the layer name is extracted by software Grasshopper programming, and the steel pipe outer diameter and wall thickness corresponding to each rod are decomposed by using the text split battery “text split” in Grasshopper; finally, transposition and data tree branch retrieval are performed to obtain the steel pipe outer diameter and wall thickness of all rods.

[0016] Preferably, step S3 is specifically: first, the intersection nodes of each rod are obtained by using the line-line intersection battery “line | line” in Grasshopper; then, a sphere with a specified length as the radius is established by using the sphere battery “sphere” in Grasshopper with the branch intersection as the center; then, each rod is truncated by using the entity trimming battery “trim with brep” in Grasshopper, and the rod on the inside side is selected to obtain the rod line model with uniform length.

[0017] Preferably, in step S4, the two straight lines of the main pipe are connected into a straight line by using the curve merging battery “join curves” in Grasshopper; the modeling method includes a shell model and a solid model; the shell model takes each rod single line as the center line, and according to the position of the center line and the outer diameter value, a pipe battery “Pipe” of Grasshopper is directly established; the solid model is programmed by using the embedded python compiler GhPython Scribe to establish a cylinder with a radius of the outer diameter and the inner diameter of the pipe along the center line, and then the two entities are subjected to Boolean operation to obtain the solid model of the hollow steel pipe.

[0018] Preferably, the entity model of the main pipe is established by obtaining the input center line, outer diameter and wall thickness, calculating the inner diameter, then creating the outer circle pipe and the inner circle pipe respectively, and obtaining the entity model of the hollow circle pipe through Boolean difference operation; and the entity model of the branch pipe is established by selecting the loop battery in the loop plug-in Anemone module, and inputting the center line, outer diameter and wall thickness of each branch pipe.

[0019] Preferably, the step S5 is specifically: performing Boolean operation between the main pipe and the branch pipes and between the branch pipes according to the spatial position and the pipe diameter size, obtaining the intersecting line and cutting off the redundant part, and the principle of cutting small rods with large rods is followed, and small pipes are placed on large pipes.

[0020] Preferably, the step S6 is specifically: collecting the main pipe and the branch pipes after mutual cutting and outputting as a standard CAD or BIM format and integrating into a design system, and the output standard CAD or BIM format includes an igs file for inputting a finite element program and a dwg file for other CAD files.

[0021] Thanks to the above technical solutions, the present application has the following technical progress.

[0022] The present application has high efficiency: only the node to be analyzed and all the rods connected thereto need to be selected, the rods are merged according to the cross-sectional specifications, the figure name is modified to the corresponding cross-sectional size, then the layer information is automatically extracted for parameterized modeling, the whole process only needs to be followed and tracked, without too much intervention, and the modeling efficiency is significantly improved.

[0023] The present application has accuracy: all the rods of the node are directly derived from the overall three-dimensional model, and the relative position relationship between the rods is accurate; the cross-sectional specification information of the rods is automatically obtained by extracting the layer name, and the intersecting topological relationship of each other is obtained through Boolean operation, so that the accuracy and consistency of the node model are ensured.

[0024] The present application has flexibility: the parameterized template of the spatial node only needs to input the three-dimensional line model of the node to be analyzed, whether it is different nodes of the same model or different nodes of different models, corresponding three-dimensional modeling can be carried out, the method supports multiple node types and design requirements, and has strong adaptability and expansibility.

[0025] The present application has integration: the generated model has strong integration in subsequent application, can be directly integrated into the existing design system in the design link, supports multidisciplinary collaborative design and analysis, can be used for node finite element analysis alone, and can be embedded in the overall model for multi-scale analysis; in the construction link, it can be used for cutting analysis of factory production and machining and construction disclosure on site. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Flow chart of the present application;

[0027] Figure 2 Example diagram of spatial node input model and layer naming of the present application;

[0028] Figure 3 Example diagram of cutting each rod according to specified length of the present application;

[0029] Figure 4 Example diagram of spatial node each rod pipe shell model of the present application;

[0030] Figure 5 Example diagram of spatial node each rod pipe shell model of the present application;

[0031] Figure 6 Example diagram of spatial node each rod pipe shell model of the present application;

[0032] Figure 7 Example diagram of spatial node each rod pipe shell model of the present application;

[0033] Figure 8 Example diagram of spatial node each rod pipe shell model of the present application;

[0034] Figure 9 Example diagram of spatial node each rod pipe shell model of the present application;

[0035] Figure 10 Example diagram of spatial node each rod pipe shell model of the present application. DETAILED DESCRIPTION

[0036] The present application will be further described in detail below in combination with the drawings and specific embodiments.

[0037] A spatial circular pipe intersecting node parameterized modeling method based on layer information, combining Figure 1 As shown in the drawings, comprising the following steps:

[0038] S1. Geometric model preparation:

[0039] Directly extract the node and all connected rod line models from the overall structure model, and name the layers in the fixed format of "PDxt", wherein P represents steel pipe, D is the outer diameter of steel pipe, t is the wall thickness of steel pipe, and x is the connection character, such as P273x10. Rods of the same specification are integrated into the same layer. All modeling length units are mm. Open the line model and layer name in Rhino, as shown in Figure 2 .

[0040] S2. Layer information extraction:

[0041] The above line model is imported into Rhino, and the geometry, spatial position, topological relationship, layer information, etc. of the connected rod of the node are automatically read. And through the layer name, the corresponding steel pipe outer diameter and wall thickness of each rod are decomposed.

[0042] In order to facilitate subsequent operation, the rod is divided into main pipe and branch pipe, and the center line corresponding to the rod is input respectively.

[0043] In the software Grasshopper, the layer information is extracted by programming, as shown in Figure 7 The battery in the figure includes: curve set (circular pipe center line), pixel identification, embedded Python operator, text segmentation, matrix transposition, tree data branch and list item. First, import three modules of Rhino, rhinoscriptsyntax and scriptcontext respectively; Then get all the pixels in the figure, and get the layer name of the layer where each pixel is located through the self-defined function, mainly using the attribute Name of the layer Layer.

[0044] After getting the layer name, the character processing is carried out in Grasshopper by using the text split battery "text split". The pipe diameter and wall thickness of each rod are obtained by cutting the layer name characters through P and x respectively; Then use the matrix transposition battery "Flip Matrix" to transpose, and classify the pipe diameter and wall thickness of all rods respectively; Then, through the tree data branch battery "Tree Branch", the branch retrieval of data tree is carried out, so as to obtain the outer diameter parameter and wall thickness parameter of all rods.

[0045] S3. Rod length unification:

[0046] The topological relationship of each rod at the node is the focus during modeling, so the rod does not need to be too long. The present application establishes a spherical surface with a specified length as the radius at the intersection point of the line model, and then intercepts each rod to obtain a rod with uniform length, as shown in Figure 3 .

[0047] At the same time, in the imported line model, the length of each rod is not the same, and the rod is too long, so it is not easy to concentrate in the node area during analysis, so the length of each rod also needs to be unified. The ball can be established with the branch pipe intersection point as the center and the specified length as the radius, and each rod is intercepted, and the adjacent side of the intersection point is selected. Usually, the length of the rod can be selected as 1.5m.

[0048] Specifically, in the imported line model, first use the line-line intersection battery "line | line" in Grasshopper to get the intersection nodes of each bar, that is, the position of the node; then take the branch intersection point as the center of the sphere, and use the sphere battery "sphere" in Grasshopper to establish a sphere with a specified length as the radius; then use the entity trimming battery "trim with brep" in Grasshopper to cut off each bar, and select the inside inside side of the bar to get the uniform length of each bar line model. As shown in Figure 8 , which includes: list items, curve sets, line-line intersection, points, and spheres.

[0049] S4. Geometric model generation:

[0050] First, the two straight lines of the main pipe are connected into a straight line in Grasshopper using the curve merging battery "join curves"; then select the modeling method, which is divided into shell model and solid model. The shell model can be directly completed using the existing battery, without wall thickness information; the solid model needs to be realized through programming.

[0051] (1) Shell model: each bar single line is the center line of the circular pipe, according to the position of the center line and the value of the outer diameter, the existing circular pipe battery "Pipe" in Grasshopper is directly used to establish the shell model of the circular pipe, as shown in Figure 9 , which mainly includes: entity trimming, curve, circular pipe, entity intersection Boolean operation, cutting between multiple pixels, and project list. The node shell model example is shown in Figure 4 .

[0052] (2) Solid model: there is no directly available battery, and the GhPython Scribe compiler is programmed to establish a cylinder with a radius of the outer diameter and the inner diameter of the circular pipe along the center line, and then the two entities are subjected to Boolean operation to obtain the hollow steel pipe solid model, as shown in Figure 10 , which mainly includes: entity trimming, curve, numerical value, number of list items, switch, loop start, additional information, list items, label characters, loop end, display mode and data record.

[0053] Specifically, in the process of establishing the solid model of the main pipe, the center line, outer diameter and wall thickness are obtained, the inner diameter is calculated, and then the outer circular pipe and the inner circular pipe are created, and the hollow circular pipe solid model is obtained through Boolean difference operation. The program is mainly: first import the Rhino.Geometry module (geometric module), then calculate the inner diameter of the circular pipe according to the input pipe diameter center curve, outer diameter D and wall thickness t, etc. 3 parameters, as shown in The outer and inner circular pipes are created by the rg.Brep.CreatePipe function, and the hollow circular pipe is obtained by the rg.Brep.CreateBooleanDifference function.

[0054] For the entity modeling of the branch pipes, the centerline, outer diameter and wall thickness are one-to-one corresponding in the sequence as the shell model, but need to be input separately for the self-programming input, so the cycle battery in the Anemone module is selected to input the centerline, outer diameter and wall thickness of each branch pipe to establish the circular pipe entity model. The node entity model is shown in the following figure. Figure 6

[0055] S5. Mutual Boolean operation:

[0056] The main pipe and each branch pipe and each branch pipe have spatial staggered topological relationships according to the spatial position and pipe diameter, which need to be solved by Boolean operation to obtain the intersecting line and cut off the redundant part to obtain the intersecting node without intersection. Among them, the main pipe and each branch pipe are cut by the main pipe to select the outer part of the main pipe; each branch pipe is placed on the large pipe according to the principle of cutting small pipe with large pipe, to ensure that the large pipe is relatively complete and the small pipe bears less force, part of which is transmitted to the node through the larger branch pipe. Specifically, the larger diameter is cut to the smaller diameter, and the two are Boolean operated one by one. The intersection topological relationship of each branch pipe node after intersection is shown in the following figure. Figure 5

[0057] S6. Result output integration:

[0058] The main pipe and each branch pipe after mutual cutting are summarized and output in standard CAD format (such as dwg file) or BIM format (such as igs file) according to different engineering requirements. If it is used for inputting finite element program (such as ANSYS, etc.), it is output in igs file; if it is used for viewing, editing and other operations in traditional CAD software (such as AutoCAD, etc.), it is output in dwg file. The output file is integrated into the existing design system, thereby supporting subsequent multidisciplinary collaborative design and analysis work, such as node finite element analysis (analysis of stress and deformation, etc.) in different software environments, or embedding the node model into the overall structure model for multi-scale analysis (such as considering the influence of the node on the overall structure stiffness, stability, etc.), which can also provide data support for the construction link, such as factory cutting size analysis (determination of cutting size, processing technology, etc.) and on-site construction briefing (let the construction personnel know the structure of the node, etc.).​​

Claims

1. A parametric modeling method for spatial circular tube intersection nodes based on layer information, characterized by: The following steps are involved: S1. Geometric model preparation: Extract the line models of nodes and their connected members from the overall structural model. Name the layers in a fixed format according to the member cross-sectional specifications, merging members of the same specification into the same layer. S2. Layer Information Extraction: Parse the layer name to determine the outer diameter and wall thickness of the steel pipe corresponding to each member, distinguish between main pipes and branch pipes, and input the centerline corresponding to each member. In step S2, the layer name is parsed to decompose the outer diameter and wall thickness of the steel pipe corresponding to each rod. Specifically, the line model is imported into Rhino, and the information of the rods connected by the node is automatically read, including but not limited to: geometric shape, spatial position, topological relationship and layer information; then, the layer name is extracted through programming in Grasshopper software, and the text split function "text split" is used in Grasshopper to decompose the outer diameter and wall thickness of the steel pipe corresponding to each rod; finally, the outer diameter and wall thickness of the steel pipe of all rods are obtained by transposing and searching the data tree branches; S3. Unify rod lengths: Create a sphere with the branch intersection as the center and the specified length as the radius. Cut each rod and select the side adjacent to the intersection. S4. Geometric model generation: Connect the two straight lines of the main pipe into a single line and select a modeling method to create the model. S5. Mutual Boolean Operations: Boolean operations are used to resolve the intersecting relationships between members, obtaining non-intersecting intersecting nodes. S6. Result output integration.

2. The parametric modeling method for spatial circular tube intersection nodes based on layer information according to claim 1 is characterized by: In step S1, all modeling length units are mm, and the layer naming format is: PDxt, where P represents the steel pipe; D is the outer diameter of the steel pipe; t is the wall thickness of the steel pipe; and x is a connecting character.

3. The parametric modeling method for spatial circular tube intersection nodes based on layer information according to claim 1 is characterized by: Step S3 specifically includes: first, using the line-line intersection battery "line | line" in Grasshopper to find the intersection nodes of each member; then, using the sphere battery "sphere" in Grasshopper to create a sphere with a specified length as the radius, with the branch intersection point as the center; then, using the entity trimming battery "trim with brep" in Grasshopper to truncate each member, and select the member on the inside side to obtain a line model of each member with a uniform length.

4. The parametric modeling method for spatial circular tube intersection nodes based on layer information according to claim 1 is characterized by: In step S4, the two straight lines of the main pipe are connected into a straight line using the curve merging cell "joincurves" in Grasshopper. The modeling methods include shell models and solid models. The shell model uses the single line of each rod as the center line and is directly established using the circular tube cell "Pipe" in Grasshopper based on the position of the center line and the outer diameter value. The solid model is programmed using the embedded Python compiler GhPython Scribe to establish a cylinder with radii of the outer diameter and inner diameter of the circular tube along the center line, and then a Boolean operation is performed on the two entities to obtain a solid model of the hollow steel pipe.

5. The parametric modeling method for spatial circular tube intersection nodes based on layer information according to claim 4 is characterized by: During the establishment of the solid model of the main pipe, the center line, outer diameter and wall thickness are obtained as input, the inner diameter is calculated, and the outer and inner tubes are created respectively. Then, the solid model of the hollow tube is obtained by Boolean difference operation. During the establishment of the solid model of the branch pipe, the circulating battery in the Anemone module of the circulating plug-in is selected, and the center line, outer diameter and wall thickness of each branch pipe are input respectively to establish the solid model.

6. The parametric modeling method for spatial circular tube intersection nodes based on layer information according to claim 1 is characterized by: The step S5 specifically includes: performing Boolean operations between the main pipe and the branch pipe, and between each branch pipe according to the spatial position and pipe diameter, obtaining the intersection line and cutting off the redundant part, and following the principle of cutting the small pipe with the big pipe between each branch pipe, with the small pipe placed on the big pipe.

7. The parametric modeling method for spatial circular tube intersection nodes based on layer information according to claim 6 is characterized by: The step S6 specifically includes: summarizing and outputting the main pipe and the branches after mutual cutting into a standard CAD or BIM format and integrating them into the design system. The output standard CAD or BIM format includes an igs file for inputting a finite element program and a dwg file for other CAD files.

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