CN107066676A - A kind of finite element automation modeling method based on satellite plate and shell structure - Google Patents

Abstract

The present invention is a finite element automatic modeling method based on the satellite plate and shell structure. Aiming at the characteristics of the satellite plate and shell structure, the mainstream finite element modeling software MSC.Patran in the domestic aerospace field is used as a platform to develop a limited Meta-Automatic Modeling System. The method includes the following steps: (1) model import; (2) model editing; (3) grid division; (4) material/element property setting; (5) load/boundary/initial condition setting; (6) submit analysis calculate. The invention can improve the knowledge integration of product structure design, standardize the product structure analysis/optimization process, shorten the model development period, and reduce the model development cost.

Description

A Finite Element Automated Modeling Method Based on Satellite Plate and Shell Structure

technical field

The invention relates to a finite element automatic modeling method, in particular to a finite element automatic modeling method based on a satellite plate shell structure, belonging to the technical field of aerospace.

Background technique

The design of spacecraft widely adopts finite element analysis technology to analyze the static and dynamic characteristics of the structure. The spacecraft finite element analysis process is generally divided into three steps: pre-processing, finite element calculation, and post-processing. At present, the finite element calculation and post-processing technology are well developed, but the finite element modeling technology with the automatic division of finite element mesh as the main feature is very weak. In the complete finite element analysis process, modeling takes up about 50% of the time , for analysts, finite element modeling requires not only multidisciplinary knowledge, but also knowledge and experience in analyzing actual projects. Only by developing the finite element automatic modeling technology based on CAD three-dimensional design model can the application of finite element analysis technology in spacecraft design be fully utilized. Specifically, the advantages of automatic finite element modeling based on CAD-based 3D design models are as follows:

1) It can make full use of the completed spacecraft structure design information to improve the efficiency of finite element modeling

2) Realize the modeling and analysis of spacecraft structure based on unified data source

3) Realize the integration of CAD/CAE and the complementary advantages of each module

4) Avoid repetitive finite element modeling and shorten the spacecraft development cycle

Contents of the invention

The technical problem to be solved by the present invention is to overcome the defects of low modeling efficiency, non-standard modeling process, low level of knowledge integration and automation in the finite element analysis process, and aiming at the characteristics of the satellite plate and shell structure, a limited Automated modeling methods for meta-analytical preprocessing work.

The technical solution adopted in the present invention is: a finite element automatic modeling method based on satellite plate shell structure, comprising the following steps:

(1) Model import;

The automatic modeling system is aimed at the 3D design model that has been processed. The user first creates a model mapping information file and puts it in the work path; then starts the Patran software, specifies the set work path and file name; finally enters the desired The location and name of the analyzed 3D design model. After submitting these information, the system will automatically complete the model import work.

The automatic modeling system is a finite element automatic modeling program developed by PCL (Patran Command Language) language programming based on the characteristics of the satellite shell structure, using the mainstream finite element modeling software MSC.Patran in the domestic aerospace field as a platform , the system has been integrated into the MSC.Patran software.

The three-dimensional design model refers to a three-dimensional CAD digital model designed by three-dimensional modeling software such as CATIA, UG, Pro/E, and SolidWorks.

The model mapping information file refers to a text file given by the user according to the product to be analyzed, which contains information such as the name of each part of the product, material type, thickness, non-structural quality, and the mutual mapping relationship between these information .

(2) Model editing;

Because most of the satellite structures are plate and shell structures, the 3D model needs to be converted into a 2D model. Model editing includes extraction of midsurfaces and model quality checks.

The mid-surface extraction refers to automatically extracting the mid-surface of the model through a program on the basis of the 3D model, eliminating the thickness of the model, and then generating a 2D model that retains the original connection/assembly information. Model quality inspection is to check and confirm the generated 2D model, and repair existing geometric defects.

(3) grid division;

On the basis of the 2D model, first set the grid type and grid size control parameters, and the system will automatically complete the 2D grid division after submission.

(4) Material/unit property setting

According to the material type information in the model mapping information file, the program automatically completes the establishment of the corresponding material model; then, according to the mutual mapping information of the thickness, non-structural quality and part names in the file, the program will complete the unit property setting and unit property assignment by itself Work.

The establishment of the material model refers to that the program calls the material models in the commonly used material model library preset when developing the system according to the provided material type. These material models have pre-specified the corresponding material parameter values, and the user only needs to Modify slightly as needed.

The unit attribute setting refers to a series of operations such as establishing the corresponding unit type name, specifying the corresponding material model, setting the unit thickness, and specifying the non-structural quality.

The unit attribute assignment refers to assigning the set unit type to the corresponding part model according to the mapping information.

(5) Load/boundary/initial condition setting.

This part of the work will vary depending on the type of analysis problem. For example, static analysis requires load setting; collision problem analysis requires boundary/initial condition setting; free modal analysis does not require load/boundary/initial condition set up.

(6) Submit analysis and calculation

After completing the preprocessing work of finite element modeling, the corresponding Nastran solver can be called for analysis and calculation according to the analysis type.

The steps (1) to (6) can be automatically completed by the program under the supervision of the user; they can also be carried out step by step in the form of human-computer interaction under the prompt of the system. At this time, the user only needs to follow the Prompt to complete some simple information input and confirmation, other complicated work will be automatically completed by the program.

The invention is a finite element automatic modeling method, which solves the problems of low modeling efficiency and irregular modeling process in the finite element analysis process, improves the knowledge integration and automation level of the finite element modeling process, and is useful for shortening the product It is of great significance to shorten the R&D cycle, improve product design performance, reduce repetitive work and liberate people's energy.

Description of drawings

Fig. 1 is a work flow chart of the present invention

Figure 2 is the automatic modeling system integration menu

Figure 3 is the Pro/E model of the plate shell box structure

Figure 4 is a 2D plate and shell structure model

Figure 5 is the grid model

Figure 6 is the material model setup

Figure 7 is the unit attribute setting

Figure 8 is the calculation result output

detailed description

A finite element automatic modeling method based on the satellite plate and shell structure of the present invention will be described in detail below in conjunction with the embodiments and drawings.

As shown in Fig. 1, the present invention provides a kind of finite element automatic modeling method based on satellite shell structure, and it specifically comprises the following steps:

(1) Model import;

The user first establishes the model mapping information file and puts it in the work path; then starts the Patran software, specifies the set work path and file name; finally enters the location and name of the 3D design model to be analyzed. After submitting these information, the system will automatically complete the model import work.

The automatic modeling system is a finite element automatic modeling program developed by PCL (Patran Command Language) language programming based on the characteristics of the satellite shell structure, using the mainstream finite element modeling software MSC.Patran in the domestic aerospace field as a platform , the system has been integrated into the MSC.Patran software, as shown in Figure 2 shows the integration menu of the system.

The three-dimensional design model refers to the three-dimensional CAD digital model designed by three-dimensional modeling software such as CATIA, UG, Pro/E, SolidWorks, etc. Here, Pro/E is used to establish a simple plate shell box structure to replace The actual satellite model is shown in Figure 3.

The model mapping information file refers to a text file given by the user according to the product to be analyzed, which contains information such as the name of each part of the product, material type, thickness, non-structural quality, and the mutual mapping relationship between these information ,As shown in Figure 4.

(2) Model editing;

Because most of the satellite structures are plate and shell structures, the 3D model needs to be converted into a 2D model. Model editing includes extraction of midsurfaces and model quality checks.

The mid-surface extraction refers to automatically extracting the mid-surface of the model through a program on the basis of the 3D model, eliminating the thickness of the model, and then generating a 2D model that retains the original connection/assembly information. Model quality inspection is to check and confirm the generated 2D model, and repair existing geometric defects. Figure 4 shows the 2D structural model obtained after the model is imported into Patran to extract the middle surface.

(3) grid division;

On the basis of the 2D model, first set the grid type and grid size control parameters, and the system will automatically complete the 2D grid division after submission. Fig. 5 shows the mesh model after meshing on the basis of the 2D model.

(4) Material/unit property setting

According to the material type information in the model mapping information file, the program automatically completes the establishment of the corresponding material model; then, according to the mutual mapping information of the thickness, non-structural quality and part names in the file, the program will complete the unit property setting and unit property assignment by itself Work.

The establishment of the material model refers to that the program calls the material models in the commonly used material model library preset when developing the system according to the provided material type. These material models have pre-specified the corresponding material parameter values, and the user only needs to Modify it slightly as needed.

The unit attribute setting refers to a series of operations such as establishing the corresponding unit type name, specifying the corresponding material model, setting the unit thickness, and specifying the non-structural quality.

The unit attribute assignment refers to assigning the set unit type to the corresponding part model according to the mapping information.

In this example we create two types of material models: Aluminum and Steel, as shown in Figure 6. According to the material type, shell thickness and non-structural quality information, a total of four element properties are set, as shown in Figure 7.

(5) Load/boundary/initial condition setting.

This part of the work will vary depending on the type of analysis problem. For example, static analysis requires load setting; collision problem analysis requires boundary/initial condition setting; free modal analysis does not require load/boundary/initial condition set up. This step needs to be added manually as needed. For the sake of simplicity, this example chooses free modal analysis, and no load/boundary/initial condition settings are made here.

(6) Submit analysis and calculation

After completing the preprocessing work of finite element modeling, the corresponding Nastran solver can be called for analysis and calculation according to the analysis type. Figure 8 shows the analysis results of the first-order free mode of the model.

Claims (2)

1. A finite element automatic modeling method based on satellite plate shell structure, is characterized in that, comprises the steps: (1) Model import; The automatic modeling system is aimed at the 3D design model that has been processed. The user first creates a model mapping information file and puts it in the work path; then starts the Patran software, specifies the set work path and file name; finally enters the desired The location and name of the analyzed 3D design model. After submitting these information, the system will automatically complete the model import work. The automatic modeling system is a finite element automatic modeling program developed by PCL (Patran Command Language) language programming based on the characteristics of the satellite shell structure, using the mainstream finite element modeling software MSC.Patran in the domestic aerospace field as a platform , the system has been integrated into the MSC.Patran software. The three-dimensional design model refers to a three-dimensional CAD digital model designed by three-dimensional modeling software such as CATIA, UG, Pro/E, and SolidWorks. The model mapping information file refers to a text file given by the user according to the product to be analyzed, which contains information such as the name of each part of the product, material type, thickness, non-structural quality, and the mutual mapping relationship between these information . (2) Model editing; Because most of the satellite structures are plate and shell structures, the 3D model needs to be converted into a 2D model. Model editing includes extraction of midsurfaces and model quality checks. The mid-surface extraction refers to automatically extracting the mid-surface of the model through a program on the basis of the 3D model, eliminating the thickness of the model, and then generating a 2D model that retains the original connection/assembly information. Model quality inspection is to check and confirm the generated 2D model, and repair existing geometric defects. (3) grid division; On the basis of the 2D model, first set the grid type and grid size control parameters, and the system will automatically complete the 2D grid division after submission. (4) Material/unit property setting According to the material type information in the model mapping information file, the program automatically completes the establishment of the corresponding material model; then, according to the mutual mapping information of the thickness, non-structural quality and part names in the file, the program will complete the unit property setting and unit property assignment by itself Work. The establishment of the material model refers to that the program calls the material models in the commonly used material model library preset when developing the system according to the provided material type. These material models have pre-specified the corresponding material parameter values, and the user only needs to Modify it slightly as needed. The unit attribute setting refers to a series of operations such as establishing the corresponding unit type name, specifying the corresponding material model, setting the unit thickness, and specifying the non-structural quality. The unit attribute assignment refers to assigning the set unit type to the corresponding part model according to the mapping information. (5) Load/boundary/initial condition setting. This part of the work will vary depending on the type of analysis problem. For example, static analysis requires load setting; collision problem analysis requires boundary/initial condition setting; free modal analysis does not require load/boundary/initial condition set up. (6) Submit analysis and calculation After completing the preprocessing work of finite element modeling, the corresponding Nastran solver can be called for analysis and calculation according to the analysis type. 2. A kind of finite element automatic modeling method based on satellite plate and shell structure according to claim 1, is characterized in that, step (1) to step (6) can be under user's supervision, by program one-click Automatic completion; it can also be carried out step by step in the form of human-computer interaction under the prompt of the system. At this time, the user only needs to complete some simple information input and confirmation according to the prompt, and the other complicated work will be automatically completed by the program.