SEA structure subsystem automatic identification method based on finite element model

Abstract

The invention belongs to the field of vibration and noise reduction, and particularly relates to an SEA structure subsystem automatic identification method based on a finite element model, and the method comprises the steps: carrying out the primary partitioning of an overall finite element model according to the material and thickness information; performing secondary partitioning on the integral finite element model according to the primary partitioning and the inter-unit connection relation data to form a plurality of SEA structure subsystems; and calculating the SEA structure subsystem attribute of the secondary partition according to the material and thickness information and the node coordinate data. The problem that the attributes of finite element model components cannot be distinguished by manually dividing subsystems can be solved, and the attributes of all units are automatically recognized during SEA structure subsystem recognition. According to the method, the SEA structure subsystem is automatically identified, so that the problems of huge workload and low modeling efficiency of manual division of the subsystem can be effectively solved, and required professional knowledge and related labor cost are greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the field of vibration and noise reduction, and specifically, it is an automatic identification method for SEA structure subsystems based on a finite element model. Background Art

[0002] In the prior art, when establishing an SEA model using a statistical energy analysis software platform, usually a finite element model with meshes is imported into the statistical energy analysis software, and then the subsystem division is carried out. The main deficiencies of this solution are as follows: First, the number of nodes in the finite element model imported into the statistical energy analysis software is large, which makes it difficult to manually select nodes or directly create nodes, reducing the modeling efficiency, and it is also difficult to ensure the accuracy. Second, since the statistical energy analysis software cannot distinguish the attributes of finite element model components, and an important principle for dividing subsystems in establishing an SEA model is that components with the same attributes can be divided into one subsystem. Therefore, after importing the finite element model with meshes into the statistical energy analysis software and then carrying out the subsystem division, the accuracy of the subsystem division cannot be guaranteed, nor can the reliability of the connection matching between subsystems be guaranteed, and the workload is huge and the modeling efficiency is low. In addition, when establishing an SEA model of an entire ship in the prior art using the statistical energy analysis software, there will be a situation where adjacent subsystems do not share nodes, further reducing the accuracy and reliability of the connection between subsystems. The automatic identification method for SEA structure subsystems based on a finite element model does not require prior knowledge of substructures, automatically divides the subsystems of the system, and automatically divides components with the same attributes into one subsystem to ensure the accuracy and reliability of the connection between subsystems. The application of the SEA subsystem automatic identification method greatly reduces the required professional knowledge and related labor costs. Summary of the Invention

[0003] In order to solve the problem that the SEA structure subsystems need to be manually divided, the present invention proposes an automatic identification method for SEA structure subsystems based on a finite element model. This calculation method is based on the segmentation of the finite element model at physically discontinuous locations, can efficiently and accurately automatically divide the subsystems, has good market application prospects, and fills the market gap.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An automatic identification method for SEA structure subsystems based on a finite element model includes initially partitioning the overall finite element model according to material and thickness information, secondarily partitioning the overall finite element model into several SEA structure subsystems according to the connection relationship data between elements, and calculating the attributes of the SEA structure subsystems in the secondary partition according to the material and thickness information and the node coordinate data.

[0006] Preferably, in step one, obtain the overall finite element model of the object to be partitioned from the preprocessing module;

[0007] In step two, perform model simplification on the overall finite element model;

[0008] In step three, obtain the material and thickness information of the object to be partitioned, and perform an initial partition on the overall finite element model according to the material and thickness information;

[0009] In step four, obtain the inter-element connection relationship data of the overall finite element model, and perform a secondary partition on the overall finite element model into several SEA structure subsystems according to the initial partition and the element boundary data;

[0010] In step five, obtain the node coordinate data of the overall finite element model, and calculate the SEA structure subsystem attributes of the secondary partition according to the material and thickness information and the node coordinate data.

[0011] Preferably, in step two, performing model simplification on the overall finite element model includes:

[0012] Delete redundant geometric features in the overall finite element model; the redundant geometric features include redundant lines, redundant surfaces, and unnecessary holes.

[0013] Preferably, in step three, performing an initial partition on the overall finite element model includes:

[0014] Obtain the material and thickness information of the object to be partitioned, where the material and thickness information refers to the material properties and thickness of each finite element, and the material properties include: density, elastic modulus, and Poisson's ratio;

[0015] Perform an initial partition on the overall finite element model according to the material and thickness information, and divide adjacent finite elements with the same material properties and thickness into one group;

[0016] The initial partition divides the overall finite element model into several groups, which are called initial SEA structure subsystems.

[0017] Preferably, in step four, performing a secondary partition on the overall finite element model includes:

[0018] Obtain the inter-element connection relationship data of the overall finite element model, where the inter-element connection relationship data refers to the included angle between adjacent finite elements and the number of finite elements adjacent through the same common edge, and the included angle between adjacent finite elements refers to the supplementary angle of the included angle between the normal vectors of two adjacent finite elements;

[0019] Perform secondary partitioning on the overall finite element model according to the inter-unit connection relationship data, and perform partitioning at the common edges where the number of finite element units adjacent through the same common edge is greater than 2 and at the common edges where the included angle between adjacent finite element units is less than 150°. The partitioning at the common edges where the number of finite element units adjacent through the same common edge is greater than 2 means partitioning the overall finite element model at the multi-surface connection points, and the partitioning at the common edges where the included angle between adjacent finite element units is less than 150° means partitioning the overall finite element model at the two-surface connection points. The selection of the threshold of 150° takes into account the influence of the mesh density on the included angle between adjacent units within the same surface, and an appropriate threshold can be selected according to the actual situation;

[0020] Based on the primary partitioning, the secondary partitioning divides the overall finite element model into several groups, which are called SEA structure subsystems.

[0021] Preferably, in the fifth step, the specific process of calculating the properties of the SEA structure subsystem is as follows:

[0022] Process a: Obtain the node coordinate data of the overall finite element model;

[0023] Process b: Calculate the area of each finite element unit through the node coordinate data;

[0024] Process c: Calculate the mass of each finite element unit using the material properties and thickness information of the finite element unit and the area of the finite element unit;

[0025] Process d: Calculate the area and mass of the SEA structure subsystem using the area of the finite element unit and the mass of the finite element unit.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. By automatically partitioning the subsystems of the system, components with the same attributes are automatically partitioned into one subsystem to ensure the accuracy and reliability of the connections between subsystems. The application of the method for automatically partitioning the SEA structure subsystem greatly reduces the required professional knowledge and related labor costs. It can effectively make up for the deficiencies of existing commercial statistical energy analysis software in the field of full-frequency underwater ship vibration and noise calculation, and at the same time provide module support for the research and development of domestic vibration and noise analysis numerical software, with broad application prospects. Description of the Drawings

[0028] Figure 1 This is the flowchart of the method for automatically identifying the SEA structure subsystem based on the finite element model of the present invention;

[0029] Figure 2 This is the diagram of the automatic identification result of the SEA structure subsystem of the ship model of the present invention. Specific Embodiments

[0030] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Please refer to Figure 1-2 , the present invention provides a technical solution for an automatic identification method of SEA structure subsystems based on a finite element model:

[0032] An automatic identification method of SEA structure subsystems based on a finite element model includes initially partitioning the overall finite element model according to material and thickness information, secondarily partitioning the overall finite element model into several SEA structure subsystems according to the inter-element connection relationship data, and calculating the attributes of the secondarily partitioned SEA structure subsystems based on the material and thickness information and the node coordinate data.

[0033] Step 1: Obtain the overall finite element model of the object to be partitioned from the preprocessing module;

[0034] Step 2: Perform model simplification processing on the overall finite element model;

[0035] Step 3: Obtain the material and thickness information of the object to be partitioned, and initially partition the overall finite element model according to the material and thickness information;

[0036] Step 4: Obtain the inter-element connection relationship data of the overall finite element model, and secondarily partition the overall finite element model into several SEA structure subsystems according to the initial partition and the element boundary data;

[0037] Step 5: Obtain the node coordinate data of the overall finite element model, and calculate the attributes of the secondarily partitioned SEA structure subsystems based on the material and thickness information and the node coordinate data.

[0038] In Step 2, performing model simplification processing on the overall finite element model includes:

[0039] Deleting redundant geometric features in the overall finite element model; the redundant geometric features include redundant lines, redundant surfaces, and unnecessary holes.

[0040] In Step 3, initially partitioning the overall finite element model includes:

[0041] Obtain the material and thickness information of the object to be partitioned. The material and thickness information refers to the material properties and thickness of each finite element unit, where the material properties include: density, elastic modulus, and Poisson's ratio;

[0042] Perform an initial partition of the overall finite element model according to the material and thickness information, and divide adjacent finite element cells with the same material properties and thickness into one group;

[0043] The initial partition divides the overall finite element model into several groups, which are called initial SEA structural subsystems.

[0044] In Step 4, perform a secondary partition of the overall finite element model, including:

[0045] Obtain the data of the connection relationship between elements of the overall finite element model. The data of the connection relationship between elements refers to the included angle between adjacent finite element cells and the number of finite element cells adjacent through the same common edge. The included angle between adjacent finite element cells refers to the supplementary angle of the included angle between the normal vectors of two adjacent finite element cells;

[0046] Perform a secondary partition of the overall finite element model according to the data of the connection relationship between elements. Divide at the common edges where the number of finite element cells adjacent through the same common edge is greater than 2 and at the common edges where the included angle between adjacent finite element cells is less than 150°. Dividing at the common edges where the number of finite element cells adjacent through the same common edge is greater than 2 means dividing the overall finite element model at the multi-surface connection, and dividing at the common edges where the included angle between adjacent finite element cells is less than 150° means dividing the overall finite element model at the two-surface connection. The selection of the threshold 150° takes into account the influence of the mesh density on the included angle between adjacent cells within the same surface, and an appropriate threshold can be selected according to the actual situation;

[0047] The secondary partition divides the overall finite element model into several groups on the basis of the initial partition, which are called SEA structural subsystems.

[0048] In Step 5, the specific process of calculating the properties of the SEA structural subsystem is as follows:

[0049] Process a: Obtain the node coordinate data of the overall finite element model;

[0050] Process b: Calculate the area of each finite element cell through the node coordinate data;

[0051] Process c: Calculate the mass of each finite element cell by using the material properties, thickness information and area of the finite element cell;

[0052] Process d: Calculate the area and mass of the SEA structural subsystem by using the area and mass of the finite element cell.

[0053] It should be noted that the present invention is a method for automatically identifying SEA structure subsystems based on a finite element model. When in use, the overall finite element model of the object to be partitioned obtained from the preprocessing module is acquired; wherein, the format of the overall finite element model is the general format of a text file exported by finite element software, and the overall finite element model is subjected to model simplification processing; wherein, the model simplification processing is performed in preprocessing software; the overall finite element model is subjected to model simplification processing to obtain the material and thickness information of the object to be partitioned, and the overall finite element model is initially partitioned according to the material and thickness information; in this step, first, the material and thickness information of the object to be partitioned needs to be obtained, and the material and thickness information refers to the material properties and thickness of each finite element unit, where the material properties include: density, elastic modulus, and Poisson's ratio, and then the overall finite element model is initially partitioned according to the material and thickness information, and adjacent finite element units with the same material properties and thickness are grouped together. Finally, the initial partitioning divides the overall finite element model into several groups, which are called initial SEA structure subsystems. The data of the connection relationship between the units of the overall finite element model is acquired, and the overall finite element model is secondarily partitioned into several SEA structure subsystems according to the initial partitioning and the unit boundary data; in this step, first, the data of the connection relationship between the units of the overall finite element model needs to be obtained, and the data of the connection relationship between the units refers to the included angle size between adjacent finite element units and the number of finite element units adjacent through the same common edge. The included angle size between adjacent finite element units refers to the supplementary angle of the included angle between the normal vectors of two adjacent finite element units. Then, the overall finite element model is secondarily partitioned according to the data of the connection relationship between the units. The partitioning is performed at the common edges where the number of finite element units adjacent through the same common edge is greater than 2 and at the common edges where the included angle between adjacent finite element units is less than 150°. The partitioning at the common edges where the number of finite element units adjacent through the same common edge is greater than 2 means partitioning the overall finite element model at the multi-surface connection points, and the partitioning at the common edges where the included angle between adjacent finite element units is less than 150° means partitioning the overall finite element model at the two-surface connection points. The selection of the threshold of 150° takes into account the influence of the mesh density on the included angle between adjacent units within the same curved surface, and an appropriate threshold can be selected according to the actual situation. In this way, the operation and use of the model are completed.

[0054] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for automatic identification of SEA structural subsystems based on finite element model, characterized in that: The overall finite element model is initially partitioned according to the material and thickness information, and the overall finite element model is secondarily partitioned into several SEA structural subsystems according to the connection relationship data between units. The properties of the SEA structural subsystems of the second partition are calculated according to the material and thickness information and the node coordinate data.

2. The SEA structural subsystem automatic identification method according to claim 1 is characterized in that: The specific steps include: Step 1, obtaining the overall finite element model of the object to be partitioned from the pre-processing module; Step 2: Simplifying the overall finite element model; Step 3: Obtain the material and thickness information of the object to be partitioned, and perform initial partitioning on the overall finite element model according to the material and thickness information; Step 4: obtaining the inter-element connection relationship data of the overall finite element model, and performing secondary partitioning of the overall finite element model into a plurality of SEA structural subsystems according to the primary partitioning and the element boundary data; Step 5: Obtain the node coordinate data of the overall finite element model, and calculate the SEA structural subsystem properties of the secondary partition according to the material and thickness information and the node coordinate data.

3. The automatic identification method of SEA structural subsystem based on finite element model according to claim 2 is characterized in that: In the step 2, the overall finite element model is simplified, including: Redundant geometric features in the overall finite element model are deleted; the redundant geometric features include redundant lines, redundant surfaces and unnecessary holes.

4. The automatic identification method of SEA structural subsystem based on finite element model according to claim 2 is characterized in that: In the step 3, the overall finite element model is initially partitioned, including: Acquire material and thickness information of the object to be partitioned, wherein the material and thickness information refers to the material properties and thickness of each finite element unit, wherein the material properties include: density, elastic modulus and Poisson's ratio; Performing a primary partitioning of the overall finite element model according to the material and thickness information, and dividing adjacent finite element units with the same material properties and thickness into one group; The initial partitioning divides the overall finite element model into several groups, which are called initial SEA structural subsystems.

5. The automatic identification method of SEA structural subsystem based on finite element model according to claim 2 is characterized in that: In the step 4, the overall finite element model is partitioned into two parts, including: Acquire inter-unit connection relationship data of the overall finite element model, wherein the inter-unit connection relationship data refers to the size of the angle between adjacent finite element units and the number of adjacent finite element units passing through the same common edge, wherein the size of the angle between adjacent finite element units refers to the supplementary angle of the angle between the normal vectors of two adjacent finite element units; The overall finite element model is partitioned twice according to the inter-unit connection relationship data, and segmented at the common edges where the number of adjacent finite element units passing through the same common edge is greater than 2 and at the common edges where the angle between adjacent finite element units is less than 150°. The segmentation at the common edges where the number of adjacent finite element units passing through the same common edge is greater than 2 refers to segmenting the overall finite element model at multi-faceted connections, and the segmentation at the common edges where the angle between adjacent finite element units is less than 150° refers to segmenting the overall finite element model at two-faceted connections, wherein the selection of the threshold value of 150° takes into account the influence of the grid density on the angle between adjacent units in the same curved surface, and an appropriate threshold value can be selected according to actual conditions; The secondary partitioning divides the overall finite element model into several groups based on the primary partitioning, which are called SEA structural subsystems.

6. The automatic identification method of SEA structural subsystem based on finite element model according to claim 2 is characterized in that: In step 5, the specific process of calculating the SEA structural subsystem properties is as follows: Process a, obtaining node coordinate data of the overall finite element model; Process b, calculating the area of ​​each finite element unit through the node coordinate data; Process c, calculating the mass of each finite element unit using the material properties and thickness information of the finite element unit and the area of ​​the finite element unit; Process d: Calculate the area and mass of the SEA structural subsystem using the finite element unit area and the finite element unit mass.

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