CN112528541A

CN112528541A - Node reconstruction-based double-curvature canopy finite element modeling method

Info

Publication number: CN112528541A
Application number: CN202011433209.9A
Authority: CN
Inventors: 王佳莹; 郭子铭
Original assignee: Shenyang Aircraft Design and Research Institute Aviation Industry of China AVIC
Current assignee: Shenyang Aircraft Design and Research Institute Aviation Industry of China AVIC
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2021-03-19

Abstract

The present application belongs to the technical field of finite element modeling, and in particular relates to a finite element modeling method for a double-curvature canopy based on node reconstruction. Including: step 1, constructing a geometric model of the cockpit cover, obtaining coordinate information of points on the geometric model, and generating a point cloud in a three-dimensional space according to the coordinate information; step 2, constructing a virtual plane, and projecting the points of the point cloud onto the virtual plane On the plane, and extract the projection points on the virtual plane as nodes; step 3, obtain the three-dimensional coordinates of the nodes on the virtual plane, and generate regularized grid units according to the three-dimensional coordinates of the nodes; step four, determine each regularized grid The normal vector of the unit is calculated, and the moving distance of the node along the corresponding normal vector is calculated; step 5, a 3D model is generated according to the node and the distance. The present application can more quickly and accurately reflect the geometric features of the structure, meet the rapid definition requirements for subsequent edge connection settings, greatly save modeling time, and improve modeling efficiency and subsequent processing efficiency.

Description

Node reconstruction-based double-curvature canopy finite element modeling method

Technical Field

The application belongs to the technical field of finite element modeling, and particularly relates to a node reconstruction-based double-curvature canopy finite element modeling method.

Background

The strength design is a necessary link of airplane design, and the existing finite element mesh drawing tool cannot completely meet the functional requirements of the strength design, which is mainly caused by the following aspects: (a) the geometric shape of the canopy is complex, the canopy is formed by multiple curved surfaces in tangent enveloping, and the workload of geometric adjustment is large when the grid division is carried out; (b) in the analysis, unit information, such as a node number, a unit number, coordinates, stress, strain and the like, needs to be extracted and calculated, the unit information needs to have higher controllability, and the controllability of the node information is difficult to ensure by traditional commercial software, so that the subsequent analysis and secondary deep calculation are not facilitated; (c) because of different calculation purposes, the finite element models with the same geometry are different in types, which requires high requirements on model processability, and the traditional commercial software lacks the capability of automatically changing grids and is not beneficial to design iteration.

Accordingly, a technical solution is desired to overcome or at least alleviate at least one of the above-mentioned drawbacks of the prior art.

Disclosure of Invention

The application aims to provide a double-curvature canopy finite element modeling method based on node reconstruction, so as to solve at least one problem in the prior art.

The technical scheme of the application is as follows:

a double-curvature canopy finite element modeling method based on node reconstruction comprises the following steps:

the method comprises the following steps of firstly, constructing a geometric model of the canopy, acquiring coordinate information of points on the geometric model, and generating point cloud in a three-dimensional space according to the coordinate information;

step two, constructing a virtual plane, respectively projecting the points of the point cloud onto the virtual plane, and extracting the projection points on the virtual plane as nodes;

acquiring three-dimensional coordinates of nodes on the virtual plane, and generating a regularized grid unit according to the three-dimensional coordinates of the nodes;

determining a normal vector of each regularized grid unit, and calculating the moving distance of the node along the corresponding normal vector;

and fifthly, generating a 3D model according to the nodes and the distance.

Optionally, in step one, a geometric model of the canopy is constructed in CAD.

Optionally, in step three, the three-dimensional coordinates of the nodes on the virtual plane are obtained through binary interpolation.

Optionally, in step three, the regularized grid cells are quadrilateral grid cells.

Optionally, in step five, the 3D model is a hexahedral mesh model.

The invention has at least the following beneficial technical effects:

according to the double-curvature canopy finite element modeling method based on node reconstruction, the established canopy transparent part finite element grid model can be used for rapidly and accurately reflecting the geometric characteristics of the structure, and meanwhile, the established node numbers can be set according to the needs of users so as to meet the requirement of rapid definition for subsequent edge connection setting, so that the modeling time is greatly saved, and the modeling efficiency and the subsequent processing efficiency are improved.

Drawings

FIG. 1 is a flow chart of a finite element modeling method for a double curvature canopy based on node reconstruction according to an embodiment of the present application;

FIG. 2 is a point cloud schematic diagram of a finite element modeling method for a double curvature canopy based on node reconstruction according to an embodiment of the present application;

FIG. 3 is a schematic virtual plane of a double curvature canopy finite element modeling method based on node reconstruction according to an embodiment of the present application;

FIG. 4 is a schematic diagram of a position after interpolation calculation by a node reconstruction-based double-curvature canopy finite element modeling method according to an embodiment of the present application;

FIG. 5 is a schematic grid generation diagram of a node reconstruction-based double curvature canopy finite element modeling method according to an embodiment of the present application;

fig. 6 is a schematic diagram of generating a 3D model by a double curvature canopy finite element modeling method based on node reconstruction according to an embodiment of the present application.

Detailed Description

In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are a subset of the embodiments in the present application and not all embodiments in the present application. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application. Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

In the description of the present application, it is to be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present application and for simplifying the description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be construed as limiting the scope of the present application.

The present application is described in further detail below with reference to fig. 1 to 6.

The application provides a double-curvature canopy finite element modeling method based on node reconstruction, which comprises the following steps:

the method comprises the following steps of firstly, constructing a geometric model of the canopy, obtaining coordinate information of points on the geometric model, and generating point cloud in a three-dimensional space according to the coordinate information;

step two, constructing a virtual plane, respectively projecting points of the point cloud onto the virtual plane, and extracting projection points on the virtual plane as nodes;

and fifthly, generating a 3D model according to the nodes and the distance.

In one embodiment of the present application, first, in step one, a geometric model of the canopy is constructed in the CAD, seeds are scattered according to the geometry of the curved surface of the geometric model or in a random sequence, and coordinate information of points on the geometric model is obtained, where the format of the coordinate information of the points is as follows:

the coordinate information of the point is recorded into a storage space and stored as a point cloud in a three-dimensional space, as shown in fig. 2.

And then, in the second step, constructing a virtual plane, respectively projecting the points of the point cloud onto the virtual plane, and extracting the projection points on the virtual plane as nodes. In this embodiment, a projection plane function is constructed according to the requirement of the designer, for example, extending along the X + direction, the Z + direction, and being equidistant, and a virtual plane node required by the designer is extracted, for example, projected to the XZ plane, as shown in fig. 3.

Further, in the third step, the three-dimensional coordinates of the nodes on the virtual plane are obtained, and the regularized grid unit is generated according to the three-dimensional coordinates of the nodes.

It is understood that, in the present embodiment, the three-dimensional coordinates of the node on the virtual plane are obtained by binary interpolation, as shown in fig. 4. And generating a quadrilateral mesh unit according to the three-dimensional coordinates of the nodes, wherein the quadrilateral mesh unit comprises a 2D shell unit formed by connecting the nodes and a corresponding extension unit, as shown in FIG. 5.

Further, in the fourth step, the normal vector of each regularized grid unit is determined, and the moving distance of the node along the corresponding normal vector is calculated, wherein the distance is the actual thickness of the canopy structure.

Finally, in step five, a 3D model is generated from the nodes and distances, as shown in fig. 6.

According to the node reconstruction-based double-curvature canopy finite element modeling method, complex geometry does not need to be processed in modeling, the CAD curved surface is rapidly processed directly in a point cloud interpolation mode, simplicity is achieved, and robustness is high; the modeling method capable of realizing software automation has the advantages that after a stroke program is executed, the modeling efficiency is high, the efficiency of establishing grids meeting requirements is improved by at least 5 times, and the subsequent processing efficiency is improved by 3 times; the node arrangement rule can not be provided by the conventional finite element mesh drawing program, the node and unit information of the method is controllable, the complete rule is controllable, and great help is provided for secondary processing and model reuse of the model.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. a double-curvature canopy finite element modeling method based on node reconstruction, is characterized in that, comprising:

Step 1. Build a geometric model of the canopy, obtain coordinate information of points on the geometric model, and generate a point cloud in a three-dimensional space according to the coordinate information;

Step 2, constructing an imaginary plane, projecting the points of the point cloud onto the imaginary plane respectively, and extracting the projection points on the imaginary plane as nodes;

Step 3, obtaining the three-dimensional coordinates of the nodes on the virtual plane, and generating regularized grid cells according to the three-dimensional coordinates of the nodes;

Step 4. Determine the normal vector of each of the regularized grid cells, and calculate the moving distance of the node along the corresponding normal vector;

Step 5. Generate a 3D model according to the nodes and distances.

2 . The method for finite element modeling of a double-curvature canopy based on node reconstruction according to claim 1 , wherein, in step 1, the geometric model of the canopy is constructed in CAD. 3 .

3 . The method for finite element modeling of a double-curvature canopy canopy based on node reconstruction according to claim 1 , wherein, in step 3, the three-dimensional coordinates of the nodes on the imaginary plane are obtained through binary interpolation. 4 .

4 . The method for finite element modeling of a double-curvature canopy canopy based on node reconstruction according to claim 1 , wherein, in step 3, the regularized mesh element is a quadrilateral mesh element. 5 .

5 . The method for finite element modeling of a double-curvature cockpit canopy based on node reconstruction according to claim 1 , wherein in step 5, the 3D model is a hexahedral mesh model. 6 .