Method for batch establishing rigid connection unit of satellite structure finite element model

Abstract

This invention proposes a method for batch creation of rigid connection elements in a satellite structural finite element model. After establishing the structural model, the method includes steps such as creating a rigid connection database (S1), creating a node information database (S2), generating a rigid element slave node table (S3), and creating rigid connection elements (S4). This significantly improves the efficiency of designers, reduces the probability of errors, and thus better leverages the guiding role of finite element analysis in structural design. Compared to previously published technologies for automatically creating satellite structural finite element models, this invention provides a more realistic depiction of connections between satellite panels, using rigid connection elements to simulate the mechanical behavior of bolts and embedded parts, thereby improving the accuracy of finite element simulation.

Description

Technical Field

[0001] This invention relates to the field of satellite structural design and mechanical analysis, specifically to the field of finite element modeling and analysis of satellite structures. Background Technology

[0002] The satellite structure is the main body of the satellite, providing support, bearing, and transmitting loads for various onboard subsystems, and belongs to the satellite's service and support subsystems. Because satellites face harsh external environments during production, transportation, launch, and on-orbit operation, a safe, reliable, and lightweight structural design is particularly important. The finite element method (FEM) is currently a mainstream method for satellite structural analysis, effectively revealing the stress state of the structure under various load conditions, identifying weak or redundant links, and quickly guiding design iterations. However, establishing a finite element model is a lengthy and complex process, especially the creation of rigid elements to characterize bolts and other connectors, which is extremely tedious and prone to errors.

[0003] Currently, mainstream finite element software in the satellite design field requires engineers to manually complete the modeling and rigid element creation work. When creating rigid elements, engineers need to select the master and slave nodes in the finite element model according to the position of bolts and other connecting parts in the 3D model, and then select the degree of freedom of the constraint according to the type of connection to complete the creation of rigid elements.

[0004] Patent document CN117010094A (application number: 202311287461.7) discloses a method for batch establishment of finite element models of single-unit satellites. The method includes the following steps: (1) preprocessing of the single-unit model; (2) calculating the mass characteristic parameters of the single unit in the satellite reference coordinate system; and (3) completing the modeling based on the parameter table. This document focuses on the process of extracting the mass characteristics of the single unit for modeling, and does not involve the establishment of rigid connection units such as bolts.

[0005] Patent document CN107066676A (application number: 201710036935.9) discloses an automated finite element modeling method based on satellite plate and shell structures. Targeting the characteristics of satellite plate and shell structures, it uses MSC.Patran, a mainstream finite element modeling software in the domestic aerospace field, as a platform and develops an automated finite element modeling system using PCL programming language. The method includes the following steps: (1) model import; (2) model editing; (3) mesh generation; (4) material / element property settings; (5) load / boundary / initial condition settings; and (6) submission for analysis and calculation. This document focuses on the automated simulation process of satellite structural plates and does not address the establishment of rigid connection elements such as bolts.

[0006] A complete micro-satellite model (<500kg) typically contains hundreds of rigid connection elements, while small and large satellite models contain hundreds or even thousands of rigid connection elements. This makes the satellite finite element modeling process extremely lengthy and prone to errors. Any error in establishing a rigid element can have a significant impact on the results. Traditional technical solutions are time-consuming and require a high level of experience and technical expertise from the designers. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for batch-establishing rigid connection elements in a satellite structural finite element model. First, a structural model of the satellite is established in CAD software based on a defined three-dimensional coordinate system. This structural model includes at least a panel representing the satellite structure and rigid connectors linking the panels. The method also includes the following steps: Establishing a rigid connector database S1 involves acquiring rigid connector data information included in the satellite structure model. This data information includes the constraint type of the rigid connector, the panel number one and panel number two connected to the rigid connector, the embedded part type of the rigid connector, and the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector's center point in the three-dimensional coordinate system. The data information is then associated with the unique number of the rigid connector to form the rigid connector database. Establishing a node information database S2 involves establishing a satellite structure finite element model based on the satellite structure model in step S1, obtaining node information from the satellite structure finite element model, and associating the three-dimensional coordinates (X2, Y2, Z2) of each node in the node information with the node number to form the node information database. The satellite structure finite element model and the satellite structure model are based on the same defined three-dimensional coordinate system. A rigid element slave node table S3 is generated. The rigid element slave node table is formed by searching for and matching the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector in the rigid connector database output in step S1 and the three-dimensional coordinates (X2, Y2, Z2) of the node in the node information database output in step S2. The matched node numbers are numbered. Establish rigid connection unit S4. In the finite element model, establish the slave nodes of the rigid connection unit according to the rigid element slave node table S3 output in step S3. The master node of the rigid connection unit is calculated and output according to all the slave nodes. The constraint degrees of freedom of the rigid connection unit are determined by the corresponding constraint type in step S1. The rigid connection unit is characterized by the slave nodes, master nodes and constraint degrees of freedom of the rigid connection unit.

[0008] Further, in step S3, the search and matching of the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector and the three-dimensional coordinates (X2, Y2, Z2) of the node is to determine the offset range A of the coordinate search. The three-dimensional coordinates (X2, Y2, Z2) of the node within the offset range A with the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector as the base point are all searched and matched to form the rigid element from the node table.

[0009] Furthermore, in step S2, the information of panel number three where the node is located is also obtained, and the panel number three and the node number are associated to form the node information database. The panel number information in panel number three comes from panel number one or panel number two in the rigid connector database in step S1.

[0010] Furthermore, in step S3, when searching for the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector as the base point and with an offset range A, the panel containing the node to be matched is first determined by matching the information of panel number one or panel number two with panel number three. Then, the three-dimensional coordinates (X1, Y1, Z1) are used as the base point and the offset range A is used to search for the three-dimensional coordinates (X2, Y2, Z2) of the matching node.

[0011] Furthermore, the offset range A is determined based on the embedded part type corresponding to the rigid connector database in step S1.

[0012] Furthermore, in step S4, the master node of the rigid connection unit calculates and outputs the average value of the corresponding slave node in the rigid unit slave node table formed in step S3.

[0013] Furthermore, based on the characteristics of the rigid connectors of the satellite structure, a data dictionary corresponding to the embedded part type and the offset range A is pre-established, and the corresponding offset range A is obtained by querying the data dictionary with the embedded part type as the condition.

[0014] Furthermore, the embedded parts include rigid connectors such as bolts, welds, or adhesives.

[0015] Compared with existing technologies, the technical solution of this application has the following beneficial effects: The method for batch establishment of rigid connection units proposed in this invention is simple and efficient, which can greatly improve the work efficiency of designers, reduce the probability of errors, and thus better leverage the guiding role of finite element analysis in structural design. Compared with the already disclosed technical solutions for automatically establishing satellite structural finite element models, this invention provides a more realistic treatment of the connections between satellite panels, using rigid connection units to simulate the mechanical behavior of bolts and embedded parts, thereby improving the accuracy of finite element simulation. Attached Figure Description

[0016] Figure 1Flowchart of the method steps for establishing a rigid connection unit; Figure 2 Satellite structural model diagram; Figure 3 : Figure 2 Enlarged view of a specific area; Figure 4 Schematic diagram of satellite finite element model; Figure 5 Schematic diagram of some nodes in the satellite finite element model; Figure 6 Schematic diagram of rigid connection unit establishment Figure 1 ; Figure 7 Schematic diagram of rigid connection unit establishment Figure 2 . Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Figure 1 The basic flow of this method is illustrated. First, a structural model of the satellite is established in CAD software based on a defined three-dimensional coordinate system. This structural model includes at least a panel representing the satellite structure and rigid connectors linking the panels, and also includes the following steps: S1 establishes a rigid connector database, specifically by acquiring rigid connector data information included in the satellite structural model. This data information includes the constraint type of the rigid connector, panel number one and panel number two connected to the rigid connector, the embedded part type of the rigid connector, and the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector's center point in the three-dimensional coordinate system. This data information is then associated with the unique number of the rigid connector to form the rigid connector database. In this embodiment, the rigid connector database is represented by Table 1 below. For ease of programming, all fields are represented numerically. For example, the constraint type is represented by 1~6 to indicate different types; this field information will determine the relevant parameters of the master node calculated from the slave node in subsequent steps. For example, if panel number one is the number 3, it indicates that the panel is a +Y plate in the structural model. If the embedded part type is the number 1, it indicates that the rigid connector in the structural model is an embedded part used for M5 bolts. The three-dimensional coordinates of the rigid connector are represented numerically as the coordinates of the center point of the current rigid connector in the satellite Cartesian coordinate system.

[0019]

[0020] S2 establishes a node information database. Specifically, based on the satellite structure model in step S1, a satellite structure finite element model is established, and the node information in the satellite structure finite element model is obtained. The three-dimensional coordinates (X2, Y2, Z2) of each node in the node information are associated with the node number to form the node information database. The satellite structure finite element model and the satellite structure model are based on the same defined three-dimensional coordinate system. In this embodiment, the node information database is represented by Table 2 below. The node number is a unique number of the node in the finite element model, which is usually related to the generation order. The node three-dimensional coordinate field is used to characterize the center point coordinates of the node in the satellite Cartesian coordinate system. Since the same defined satellite Cartesian coordinate system is used in both the satellite structure model and the finite element model, it can be understood that there may be a certain corresponding matching relationship between the coordinate positions of the rigid connectors in the "rigid connector database" and the three-dimensional coordinates of the nodes in the "node information database" in the finite element model. Using this matching relationship, the rigid connectors can be characterized by nodes (groups) in the finite element model.

[0021]

[0022] A rigid element slave node table S3 is generated. Based on the three-dimensional coordinates (X1, Y1, Z1) of the rigid connectors in the rigid connector database output in step S1 and the three-dimensional coordinates (X2, Y2, Z2) of the nodes in the node information database output in step S2, a search and matching process is performed. The matched node numbers are then numbered to form the rigid element slave node table. In this embodiment, Table 3 represents the rigid element slave node table. This step is crucial to the method. After establishing the rigid connector database and the node information database, the coordinate position correspondence between the rigid connectors and nodes in both databases is used to form nodes (groups) representing the rigid element slave nodes through a search and matching process. These nodes (groups) can be single or multiple. The specific search and matching can be based on precise coordinate position correspondence or a defined search range to form nodes (groups).

[0023]

[0024] A rigid connection unit S4 is established. In the finite element model, the slave nodes of the rigid connection unit are established according to the rigid element slave node table S3 output in step S3. The master node of the rigid connection unit is calculated and output based on all the slave nodes. The constraint degrees of freedom of the rigid connection unit are determined by the corresponding constraint type in step S1. The slave nodes, master nodes, and constraint degrees of freedom of the rigid connection unit characterize each rigid connection element. In this embodiment, after the slave node table characterizing the rigid element is formed in step 3, it indicates that each slave node has been established in batches, and the corresponding master node can be determined by calculation using the nodes (groups) of each slave node. The basis for calculation will vary depending on the specific satellite structure project. In this embodiment, the master node of the rigid connection unit is calculated and output based on the average value of the corresponding slave nodes in the rigid element slave node table formed in step S3.

[0025] In the above embodiment, step S3 forms nodes (groups) based on coordinate search and matching. In a more preferred embodiment, the search and matching of the rigid connector's three-dimensional coordinates (X1, Y1, Z1) and the node's three-dimensional coordinates (X2, Y2, Z2) determines the offset range A of the coordinate search. Using the rigid connector's three-dimensional coordinates (X1, Y1, Z1) as the base point, all node three-dimensional coordinates (X2, Y2, Z2) within the offset range A are searched and matched to form a rigid unit node table. Thus, the rigid connectors that need to be matched and characterized in the "rigid connector database" will form multiple corresponding nodes (groups) according to this search and matching rule. The node numbers in these nodes (groups) are all nodes whose node three-dimensional coordinates (X2, Y2, Z2) are relative to the rigid connector's three-dimensional coordinates (X1, Y1, Z1) within the offset range A.

[0026] The above implementation uses coordinate offset range search matching to determine the nodes (groups) representing rigid connectors. This method results in a large search range, requiring a search within offset range A in each dimension of the space. To narrow the search range, in step S2, the panel number three information of the node is also obtained. This panel number three is associated with the node number to form the node information database. The panel number information in panel number three comes from panel number one or panel number two in the rigid connector database from step S1. In Table 2 above, panel number three is recorded in the "node information database." The record of panel number three is beneficial for narrowing the search matching range, indicating that the current node in the "node information database" belongs to a specific panel, and this panel matches panel number one or panel number two in the "rigid connector database." For example, if the slave node to be searched is located in the rigid connector database, and the fields "Panel Number 1" and "Panel Number 2" are 1 (indicating a +X panel) and 2 (indicating a -X panel) respectively, then when searching for matching slave nodes in the "Node Information Database," the panel can be matched first based on the "Panel Number 3" field, and then the search can be performed. This narrows the search range and improves the speed and accuracy of searching for matching slave nodes. For example, in the aforementioned example, searching for matching slave nodes will find nodes whose distances from the rigid connector's three-dimensional coordinates Y2 and Z2 to both Y1 and Z1 are less than the offset range A, thus forming the nodes (groups) representing the rigid element in the "Slave Node Table."

[0027] In the above implementation, the offset range A determines the search matching range of the node. In this implementation, the offset range A is determined based on the embedded part type corresponding to the rigid connector database in step S1. Different embedded part types may have different offset ranges A. For example, the embedded part size of an M5 bolt is approximately 15mm × 15mm. Considering the influence area of ​​the foam adhesive, the node search offset range A is taken as 25mm × 25mm. For other embedded part types such as welded or glued rigid connectors, different search offset ranges A are adopted according to their structural parameter characteristics. To facilitate implementation and table lookup, in this implementation, a data dictionary corresponding to embedded part types and offset ranges A is pre-established based on the characteristics of the rigid connectors in the satellite structure. The data dictionary is queried using the embedded part type as a condition to obtain the corresponding offset range A.

[0028] The above describes the basic steps and implementation principle of the rigid element batch creation method proposed in this invention. The following uses the four bolts between two panels in a satellite structure model to illustrate the implementation of rigid element batch creation in detail.

[0029] Figure 2This shows the satellite structure model, with the circles indicating the locations of the four bolts mentioned above in the model. Figure 3 This is a magnified view of that location. Based on Figure 3 By using the center point coordinates of the four M5 bolt connectors (including embedded parts) and other relevant information, the rigid connector database in step S1 can be generated, as shown in the table below.

[0030]

[0031] Figure 4 This is a finite element model diagram of the satellite. Figure 5 The output then shows the nodes based on panel 1 and panel 2. The table below shows the node information database output in step S2.

[0032]

[0033] Based on the information such as the coordinates of the connectors recorded in the rigid connector database, the node numbers that are less than 25mm×25mm away from the center of the connector are retrieved from the node information database, and the rigid element slave node table representing these four bolts in step S3 can be generated (as shown in the table below).

[0034]

[0035] Based on the rigid element node table generated above, the master nodes are formed in the finite element model using the calculation criteria in step S4, ultimately forming the following... Figure 6 and Figure 7 The modeling effect of establishing rigid connection elements is shown.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for batch establishing rigid connection elements in a satellite structural finite element model, comprising first establishing a satellite structural model in CAD software based on a defined three-dimensional coordinate system, the structural model including at least a panel representing the satellite structure and rigid connectors connecting the panels, characterized in that, It also includes the following steps: S1: Establish a rigid connector database, specifically by acquiring rigid connector data information included in the satellite structure model. The data information includes the constraint type of the rigid connector, the panel number one and panel number two connected to the rigid connector, the embedded part type of the rigid connector, and the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector center point in the three-dimensional coordinate system. The data information and the unique number of the rigid connector are associated to form the rigid connector database. S2: Establish a node information database. Specifically, based on the satellite structure model in step S1, establish a satellite structure finite element model, obtain the node information in the satellite structure finite element model, and associate the three-dimensional coordinates (X2, Y2, Z2) of each node in the node information with the node number to form the node information database. The satellite structure finite element model and the satellite structure model are based on the same determined three-dimensional coordinate system. S3: Generate a rigid element slave node table. Based on the rigid connector 3D coordinates (X1, Y1, Z1) in the rigid connector database output in step S1 and the node 3D coordinates (X2, Y2, Z2) in the node information database output in step S2, search and match, and number the matched node numbers to form a rigid element slave node table. Specifically, determine the offset range A of the coordinate search, and with the rigid connector 3D coordinates (X1, Y1, Z1) as the base point, the node 3D coordinates (X2, Y2, Z2) within the offset range A are all searched and matched to form a rigid element slave node table. S4: Establish rigid connection elements. In the finite element model, establish the slave nodes of the rigid connection elements according to the rigid element slave node table output in step S3. The master nodes of the rigid connection elements are calculated and output according to all the slave nodes. The constraint degrees of freedom of the rigid connection elements are determined by the corresponding constraint type in step S1. The rigid connection elements of each rigid connection component are characterized according to the slave nodes, master nodes, and constraint degrees of freedom of the rigid connection elements.

2. The method for batch establishing rigid connection elements of a satellite structure finite element model as described in claim 1, characterized in that, In step S2, the information of panel number three where the node is located is also obtained, and the panel number three and the node number are associated to form the node information database. The panel number information in panel number three comes from panel number one or panel number two in the rigid connector database in step S1.

3. The method for batch establishing rigid connection elements of a satellite structure finite element model as described in claim 2, characterized in that, In step S3, when searching for the three-dimensional coordinates (X1, Y1, Z1) of the rigid connector as the base point and using the offset range A, the panel containing the required matching node is first determined by matching the information of panel number one or panel number two and panel number three. Then, the three-dimensional coordinates (X1, Y1, Z1) are used as the base point and the offset range A is used to search for the three-dimensional coordinates (X2, Y2, Z2) of the matching node.

4. The method for batch establishing rigid connection elements of a satellite structure finite element model as described in claim 1, characterized in that, The offset range A is determined based on the embedded part type corresponding to the rigid connector database in step S1.

5. The method for batch establishing rigid connection elements of a satellite structure finite element model as described in claim 1, characterized in that, In step S4, the master node of the rigid connection unit calculates and outputs the average value of the corresponding slave node in the rigid unit slave node table formed in step S3.

6. The method for batch establishing rigid connection elements of a satellite structure finite element model as described in claim 4, characterized in that, Based on the characteristics of rigid connectors in the satellite structure, a data dictionary is pre-established that corresponds to the type of embedded part and the offset range A. The corresponding offset range A is obtained by querying the data dictionary using the type of embedded part as a condition.

7. The method for batch establishing rigid connection elements of a satellite structure finite element model as described in claim 1, characterized in that, The types of embedded parts include bolts, welding, or adhesive bonding.

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