CN116911143A

CN116911143A - Free-form surface space structure parameterized modeling method based on finite element analysis software

Info

Publication number: CN116911143A
Application number: CN202311112017.1A
Authority: CN
Inventors: 张晨; 江重阳; 张昊强; 乔帅斌; 李亚兰; 张强; 陈振福; 李煜
Original assignee: Gansu Architectural Design Research Institute Co ltd
Current assignee: Gansu Architectural Design Research Institute Co ltd
Priority date: 2023-08-31
Filing date: 2023-08-31
Publication date: 2023-10-20

Abstract

The invention discloses a space free-form surface parametric modeling method based on finite element software, which comprises the steps of establishing a three-dimensional cad model of a space free-form surface space model control line, and importing cad files into the finite element software; by utilizing the function of generating a curved surface through a closed curve, a space curved surface; performing grid division on the space curved surface by using an automatic grid division function to obtain an automatic grid division model; and re-meshing the automatic meshing model by using a re-meshing function, customizing the mesh types and the mesh sizes, re-meshing the automatic meshing model, obtaining a self-defining type mesh model, exporting a stl file, importing 3DS MAX software, exporting a CAD format file, and completing parameterized modeling of the free-form surface space structure. The modeling method is simple, convenient and efficient, can be mastered quickly, and can be modified and adjusted quickly according to later-period requirements.

Description

Free-form surface space structure parameterized modeling method based on finite element analysis software

Technical Field

The invention relates to a parameterized modeling method of a free-form surface space structure, in particular to a method for rapidly arranging geometric grids of a rod piece of an irregular surface space structure and rapidly converting a finite element model into cad format files which can be identified by calculation software.

Background

At present, the requirements for complex special-shaped buildings are increasing, larger projects such as stadiums, exhibitions, museums, stations, airports, terminal buildings and the like, and smaller projects such as buildings of building selling centers, gates and the like all show enthusiasm for irregular shapes. The complicated special-shaped space structure is developed under the requirement, and the building with beautiful shape can be built.

Irregular special-shaped curved surfaces cannot be accurately described by mathematical functions, so that the irregular curved surfaces are circulated when structural modeling is performed, and great difficulty exists.

Modeling methods in the prior art are generally of the following types: modeling functions of standard grids are carried in grid computing and analyzing software such as MST, 3D3S and the like, and categories such as grid frames, grid shells and the like can be selected according to a geometric model to be built; the general finite element software such as Midas Gen and SAP2000 also has some basic space structure modeling functions, and a model is built by inputting key parameters, and the space structure is generated in a similar manner to professional space structure software such as MST; manually drawing a grid model of the space structure rod piece by using CAD software such as Autocad, rhino and the like; the programming modeling was visualized using a grasshopper plug-in the rho software. A large number of regular or irregular projects are built by using the modeling method in the prior art, but the modeling efficiency is relatively low, the modeling is labor-consuming and is easy to make mistakes, and the method with no unified regularity is circulated.

Therefore, a need exists to find a rapid, automatic, and easy to master modeling method for a spatially irregular surface.

Disclosure of Invention

The invention aims to provide a free-form surface space structure parameterized modeling method with high modeling efficiency based on finite element software.

Parametric modeling is a technique widely used in the fields of computer aided design and engineering. It allows for more flexible and efficient creation and modification of models by using parameters to define and control the features and properties of the model. Through parametric modeling, a designer can relate the size, shape, etc. attributes of a model to specific numerical parameters. In this way, when a model needs to be modified, only the values of the parameters need to be adjusted, and the whole model does not need to be redrawn. This flexibility makes parametric modeling an important tool in the design process, which can greatly improve the efficiency and accuracy of the design. In the step 3, the rod piece geometric grid of the irregular curved surface space structure is arranged in a parameterization mode by customizing the grid size in finite element software FEA.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a space free-form surface parameterization modeling method based on finite element software comprises the following steps:

s1: establishing a three-dimensional cad model of a spatial model control line (such as a ridge line, a valley line, a ridge line and the like) of a spatial free-form surface, and importing cad files of the spatial model control line into finite element software (FEA);

s2: obtaining a space curved surface by utilizing the function of generating a curved surface through a closed curve in finite element software;

s3: using the function of automatic grid division of finite element software to grid-divide the space curved surface to obtain an automatic grid division model; then, the grid re-dividing function of finite element software is used for customizing the grid type and the grid size, re-dividing the automatic grid-dividing model into grids of the self-defining type, obtaining the grid model of the self-defining type, leading in 3DS MAX software, leading out CAD format files through the 3DS MAX software, and completing the parametric modeling of the free-form surface space structure.

The modeling method of the invention utilizes the powerful and efficient grid division function of finite element analysis software, realizes the rapid arrangement of the geometric grids of the rod piece with the irregular curved surface space structure through few software commands, converts the finite element model into cad format files which can be identified by general computing software (such as MIDAS GEN, YJK, SAP2000 and the like), obtains the cad format files, and then leads the general computing software into the cad format files to realize the computing analysis and design of the rod piece. The modeling method is simple, convenient and efficient, can be mastered quickly, and can be modified and adjusted quickly according to the later-period requirement.

Drawings

FIG. 1 is a schematic modeling flow diagram of the modeling method of the present invention.

FIG. 2 is a schematic diagram of a CAD file of spatial fold model ridgeline to be modeled in an embodiment.

Fig. 3 is a schematic diagram of a space surface generated after the CAD file shown in fig. 2 is imported into finite element software.

Fig. 4 is a schematic diagram of a quadrilateral mesh after the space surface shown in fig. 3 is automatically meshed.

Fig. 5 is a schematic diagram of the re-division of the quadrilateral mesh of fig. 4 into triangular meshes.

FIG. 6 is a cad format file derived from the schematic diagram of FIG. 5 after importing 3DS MAX software.

Detailed Description

The invention will be described in detail below with reference to the drawings and the detailed description.

Example 1

The maximum span of a certain space fold surface model along the long direction is 125.6m, the short direction span is about 12.0 m-24.0 m, and the highest point height is 29.9m. The space folding surface is composed of 28 space inclined triangular surfaces, and 48 ridge lines are formed at the joint positions of the triangular surfaces. The space fracture surface is parameterized and modeled based on finite element software, and a modeling flow chart is shown in fig. 1. The modeling process of the space folding surface model comprises the following steps:

s1: in graphic software, such as Autocad or Rhino software, a three-dimensional ridge (ridge) model of the spatial fold model is built, as in FIG. 2; importing the CAD file of the three-dimensional ridge line model into finite element software;

s2: generating a space curved surface by utilizing the function of generating a curved surface through a closed curve in finite element software, as shown in figure 3;

s3: performing grid division on the space curved surface by using an automatic grid division function of finite element software to obtain a software default quadrilateral grid model; then, using the function of re-dividing the grids, selecting the grid type as a triangle, and customizing the grid size to obtain a triangle grid model; and (3) exporting a stl file of the triangular mesh model, importing 3DS MAX software, exporting a CAD format file through the 3DS MAX software, and completing parameterized modeling of the free-form surface space structure.

In the prior art, CAD software such as Autocad, rhino is generally utilized to directly draw a grid model of a space structure, so that the method is labor-consuming and time-consuming. Taking example 1 as an example, the Autocad software is used for directly drawing the grid at least for one day, and the uniformity of the size and the rationality of the topology of the grid are required to be adjusted in the later period, but the modeling method of the invention only needs less than one hour to divide the grid, so that the working efficiency is greatly improved, and the size of the model grid is uniform and the topology is reasonable.

The traditional parametric modeling method is realized by utilizing a grasshopper plug-in the rho software through programming, has higher technical difficulty and higher requirement on logic thinking capability of technicians, and is basically fixed-flow type operation, and the process is simple and convenient to master.

Claims

1. The space free-form surface parameterization modeling method based on finite element software is characterized by comprising the following steps of:

s1: establishing a three-dimensional cad model of a space model control line of a space free-form surface, and importing cad files of the space model control line into finite element software;

s2: obtaining a space curved surface by utilizing the function of finite element software of generating a curved surface through a closed curve;

2. The method of modeling a free-form surface in space based on finite element software according to claim 1, wherein in step S1, the control lines of the spatial model are ridge lines, valley lines and ridge lines.

3. The method for parameterized modeling of a free-form surface in space based on finite element software according to claim 1, wherein in step S3, the custom mesh type is a triangle.