Cartridge receiver connection structure model correction method and system based on super-unit

Abstract

The invention provides a super-unit-based cartridge receiver connection structure model correction method and system. The method comprises the following steps: splitting a cartridge receiver into a plurality of substructures and establishing an initial finite element model; performing modal test on the substructures and modal analysis on the initial finite element model, and correcting the initial finite element model into a basic finite element model; assembling the basic finite element models to form a finite element model of the casing connection structure; carrying out super-unit division on the finite element model of the cartridge receiver connection structure into a super-unit structure and a residual substructure, and carrying out modal analysis; and assembling to form a cartridge receiver connection structure model and carrying out a modal test to complete correction. According to the method, each initial finite element model is subjected to layered correction, then the finite element model of the cartridge receiver connection structure is subjected to super-unit division, the original overall model correction mass is disassembled into a plurality of steps, and the precision requirement of the corrected cartridge receiver connection structure model is met by improving the precision of each part of the cartridge receiver connection structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of casing connection structures, and particularly relates to a method and system for modifying a casing connection structure model based on super elements. Background Art

[0002] The casing connection structure is a key component of an engine and also the core structure for bearing and transmitting the loads of the casing load-bearing system. The casing will exhibit complex mechanical behaviors under load excitation, and accurately analyzing the dynamic characteristics of the structure is not only an important basis for precisely predicting the mechanical behaviors of the casing under load excitation but also an important basis for ensuring the service safety of the system.

[0003] In practical applications, due to the complex structural form and numerous connections of an aeroengine casing, the existing finite element models of the casing usually have large calculation file sizes, are difficult to accurately characterize the connection interfaces, and have high requirements for computer hardware. Furthermore, the connection boundary conditions between the various components of the casing cannot be accurately considered, resulting in inaccurate prediction of the structural mechanical behaviors.

[0004] Although the existing model modification methods can effectively improve the accuracy and prediction ability of the structure, most of the research is directly carried out on the full casing model, that is, directly modifying the full casing model. Considering the complexity of the casing connection structure, this leads to a significant increase in the calculation cost and a significant reduction in the model modification efficiency.

[0005] In view of this, overcoming the above-mentioned defects of the existing technologies is an urgent problem to be solved in this technical field. Summary of the Invention

[0006] In view of the above problems, the present invention proposes a method for modifying a casing connection structure model based on super elements, including the following steps:

[0007] Split the casing into several substructures and establish initial finite element models for the several substructures;

[0008] Conduct modal tests on the substructures and conduct modal analyses on the initial finite element models, and modify the initial finite element models into basic finite element models based on the results of the modal tests and modal analyses;

[0009] Assemble the several basic finite element models to form a finite element model of the casing connection structure;

[0010] Divide the finite element model of the casing connection structure into super elements, dividing it into a super element structure and a residual substructure;

[0011] Conduct modal analyses on the super element structure and the residual substructure;

[0012] Assemble the super element structure and the residual substructure to form a casing connection structure model, conduct a modal test on the casing connection structure model, and complete the modification of the casing connection structure model in combination with the modal analysis of the super element structure and the residual substructure.

[0013] Furthermore, establish the initial finite element models of several substructures, which specifically include the following steps:

[0014] Obtain the design parameters of the casing and construct the geometric model of the substructure;

[0015] Perform three-dimensional solid element mesh division on the geometric model of the substructure to obtain a number of finite elements, and a number of finite elements are combined to form the initial finite element model of the substructure.

[0016] Furthermore, before conducting the modal test on the substructure, it includes the following steps:

[0017] Conduct modal analysis based on the initial finite element model to obtain the modal theoretical frequencies and theoretical vibration modes, and arrange the measuring point positions on the substructure according to the modal theoretical frequencies and theoretical vibration modes;

[0018] The measuring point positions include axial measuring points and circumferential measuring points;

[0019] The number of axial measuring points at the measuring point positions is consistent with the number of axial wave peaks corresponding to the theoretical vibration mode, and the number of circumferential measuring points is consistent with the number of circumferential wave peaks corresponding to the theoretical vibration mode.

[0020] Furthermore, assemble a number of basic finite element models to form a finite element model of the casing connection structure, which specifically includes:

[0021] Import a number of basic finite element models into the finite element software, use the node coincidence method to represent the connection components for connecting adjacent substructures, and establish the contact model of the connection components;

[0022] Align and assemble a number of basic finite element models with the contact models of a number of connection components to form a finite element model of the casing connection structure;

[0023] Among them, the element attribute of the contact model is set as virtual material.

[0024] Furthermore, divide the finite element model of the casing connection structure into a super element structure and a residual substructure, which specifically includes:

[0025] Obtain the connection interface of the flange connection component in the finite element model of the casing connection structure;

[0026] Taking the connection interface of the flange connection component as the division boundary, divide the finite element model of the casing connection structure into super element division to form two super element structures and one or more residual substructures connecting the two super element structures;

[0027] A flange connecting member for docking with an adjacent super element structure or residual sub-structure is sleeved at the end of the residual sub-structure.

[0028] Furthermore, modal analysis is performed on the super element structure and the residual sub-structure, specifically including:

[0029] The super element structure is condensed using the modal synthesis method to obtain the mass matrix and stiffness matrix of each super element structure;

[0030] The mass matrix and stiffness matrix of the super element structure are assembled into the residual sub-structure for calculation file assembly;

[0031] Define the response output and result form in the calculation file, and submit it to the solver for modal analysis of the super element structure and the residual sub-structure.

[0032] Furthermore, during the modal test of the casing connection structure model, the measuring point positions and excitation directions of the casing connection structure model are kept consistent with those of the measuring points and excitation directions on the sub-structure.

[0033] Furthermore, the completion of the modification of the casing connection structure model specifically includes:

[0034] Use the mathematical model to adjust the flange virtual material parameters in the residual sub-structure until the consistency between the modal analysis and the experimental test vibration modes is determined;

[0035] Update the casing connection structure model to complete the modification.

[0036] The present invention also proposes a system for modifying a casing connection structure model based on super elements, including:

[0037] A model construction unit for splitting the casing into several sub-structures and establishing the initial finite element models of several sub-structures;

[0038] A first modification unit for performing modal tests on the sub-structures and modal analysis on the initial finite element models, and modifying the initial finite element models into basic finite element models based on the results of the modal tests and modal analysis;

[0039] A model assembly unit for assembling several basic finite element models to form a finite element model of the casing connection structure;

[0040] A model division unit for performing super element division on the finite element model of the casing connection structure, dividing it into super element structures and residual sub-structures;

[0041] A model analysis unit for performing modal analysis on the super element structures and the residual sub-structures;

[0042] A second correction unit is used to assemble the super element structure and the residual substructure to form a casing connection structure model, conduct a modal test on the casing connection structure model, and complete the correction of the casing connection structure model by combining the modal analysis of the super element structure and the residual substructure.

[0043] Furthermore, the model division unit is specifically used for:

[0044] Obtain the connection interface of the flange connector in the finite element model of the casing connection structure;

[0045] Taking the connection interface of the flange connector as the division boundary, perform super element division on the finite element model of the casing connection structure to form two super element structures and one or more residual substructures connecting the two super element structures;

[0046] A flange connector for docking with an adjacent super element structure or residual substructure is sleeved at the end of the residual substructure.

[0047] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0048] The method for correcting the casing connection structure model based on super elements of the present invention first performs hierarchical correction on each initial finite element model, then performs super element division on the finite element model of the casing connection structure, conducts a modal test based on the casing connection structure model, and combines the modal analysis of the super element structure and the residual substructure; disassembles the large amount of the original overall model correction into several steps, meets the accuracy requirements of the corrected casing connection structure model by improving the accuracy of each component of the casing connection structure, reduces the requirements for computer hardware, the scale of calculation files and production costs, and thereby improves the correction efficiency of the corrected casing connection structure model.

[0049] Other features and advantages of the present invention will be described in the following description of the specification, and some of them will become obvious from the description of the specification, or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0051] Figure 1 Shows the flow schematic of the method for correcting the casing connection structure model based on super elements in the embodiments of the present invention Figure 1 ;

[0052] Figure 2 Shows a schematic diagram of the initial finite element model in an embodiment of the present invention;

[0053] Figure 3 Shows a schematic diagram of the modal test in an embodiment of the present invention;

[0054] Figure 4 Shows a schematic diagram of the measuring point distribution in an embodiment of the present invention;

[0055] Figure 5 Shows a schematic diagram of the super - element division in an embodiment of the present invention;

[0056] Figure 6 Shows a block diagram of the casing connection structure model correction system based on super - elements in an embodiment of the present invention;

[0057] Figure 7 Shows the flow schematic of the casing connection structure model correction method based on super - elements in an embodiment of the present invention Figure 2 ;

[0058] Figure 8 Shows a schematic diagram of the objective function of the casing connection structure model correction in an embodiment of the present invention.

[0059] In the figure, the first casing 1, the second casing 2, the third casing 3, the exciter 4, the elastic rope 5, the rigid support 6, the sensor 7, the spectrum analyzer 8, the first super - element 9, the residual sub - structure 10, the second super - element 11. Detailed implementation manners

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0061] The present invention provides a casing connection structure model correction method based on super - elements, Figure 1 Shows a flow schematic diagram of the casing connection structure model correction method based on super - elements in an embodiment of the present invention, Figure 1 In which, the casing connection structure model correction method based on super - elements includes:

[0062] S101. Split the casing into several sub - structures and establish the initial finite element models of the several sub - structures;

[0063] Among them, establishing the initial finite element models of the several sub - structures specifically includes the following steps:

[0064] Obtain the design parameters of the casing and construct the geometric model of the substructure;

[0065] Perform three-dimensional solid element mesh division on the geometric model of the substructure to obtain a number of finite elements, and a number of finite elements are combined to form the initial finite element model of the substructure.

[0066] Among them, each finite element is a hexahedron structure, and after the mesh division is completed, the material properties of each unit are consistent. Exemplarily, the mesh size is 5 mm to ensure that there are 2 layers of meshes in the casing thickness, and the unit is in the shape of a hexahedron.

[0067] Take Figure 2 as an example, the whole casing is split into three parts, which are respectively set as the first casing 1, the second casing 2, and the third casing 3. The information of the initial finite element models of the corresponding substructures is shown in Table 1.

[0068] Table 1 Information of the initial finite element models of each substructure

[0069] Structure Number of units Number of nodes First casing 1 25020 37620 Second casing 2 6840 10980 Third casing 3 15840 24480

[0070] At the same time, the materials of each substructure are set to the nominal values of steel, that is, the elastic modulus E = 206 GPa, the Poisson's ratio μ = 0.3, and the density ρ = 7800 kg / m 3 .

[0071] S102. Conduct modal tests on the substructure and perform modal analysis on the initial finite element model, and modify the initial finite element model to the basic finite element model based on the results of the modal test and modal analysis;

[0072] Among them, before conducting the modal test on the substructure, the following steps are included:

[0073] Based on the modal analysis of the initial finite element model, obtain the modal theoretical frequencies and theoretical vibration modes, and arrange the measuring point positions on the substructure according to the modal theoretical frequencies and theoretical vibration modes;

[0074] The measuring point positions include axial measuring points and circumferential measuring points;

[0075] The number of axial measuring points at the measuring point positions is the same as the number of axial wave peaks corresponding to the theoretical vibration mode, and the number of circumferential measuring points is the same as the number of circumferential wave peaks corresponding to the theoretical vibration mode.

[0076] It should be added that the modal frequency refers to the natural vibration frequency of the casing in a specific mode, that is, the frequency at which the structure will vibrate naturally without external forced vibration. Each modal frequency corresponds to a specific vibration mode. Different modal order numbers correspond to different modal frequencies.

[0077] The mode order includes the axial order and the circumferential order; among them, the axial order: the vibration mode along the axial direction of the casing, represented by the number of half-waves; the circumferential order: the vibration mode along the circumferential direction of the casing, represented by the number of half-waves.

[0078] Axial half-wave number: Describes the vibration mode along the axial direction of the casing, that is, the number of fluctuations formed in the axial direction;

[0079] Circumferential half-wave number: Describes the vibration mode along the circumferential direction of the casing, that is, the number of fluctuations around the circumference of the casing.

[0080] In Figure 3 In the example shown, the measuring point arrangement and the modal test suspension scheme are presented. Through modal analysis, the modal theoretical frequencies and theoretical mode shapes of the initial finite element model can be obtained:

[0081] Exemplarily, the axial half-wave number corresponding to the modal theoretical frequency is 2, indicating that two complete vibration wave peaks (or two sine half-waves) are formed along the axial direction of the casing;

[0082] The circumferential half-wave number is 6, indicating that 6 wave peaks are formed in the circumferential direction of the casing.

[0083] This indicates that within the range of this modal theoretical frequency, the highest-order mode shape of the casing will have two half-waves along the axial direction and six half-waves along the circumferential direction.

[0084] Correspondingly, the arrangement direction of the measuring points corresponds to the axial order and the circumferential order, including 2 directions of circumferential and axial. The measuring point positions include the axial measuring point positions and the circumferential measuring point positions; for the specific arrangement of the axial measuring point positions, refer to Figure 4 On the right side, the axial measuring point positions include R1, R2, R3, R4, R5, R6; for the specific arrangement of the circumferential measuring point positions, refer to Figure 4 On the left side, the circumferential measuring point positions include R1, R2... R24. The arrangement of the measuring point positions enables the modal test of the substructure to present the required mode wave numbers.

[0085] So that during the subsequent modal test, the substructure is suspended on the rigid support 6 by the elastic rope 5, and it is ensured that the elastic rope 5 has sufficient spatial deformation freedom in the suspended state to meet the condition requirements for realizing the free boundary of the substructure. An external force is applied through the exciter 4 or the impact hammer, and at the same time, the vibration response of the measuring point positions of the substructure is recorded by the sensor 7, and the modal frequencies and mode shapes corresponding to several substructures are extracted through the spectrum analyzer 8.

[0086] At the same time, through the comparison between the modal theoretical frequencies, theoretical mode shapes and the test modal frequencies, test mode shapes of the modal test, the correction operation of the substructure is carried out, and the initial finite element model is corrected to the basic finite element model. Among them, the following optimization design mathematical model is adopted during the correction:

[0087]

[0088] Where: F(x) represents the weighted sum of squares of the casing modal frequency errors; i represents the modal frequency counter involved in the correction in each section of the casing structure; N s represents the total number of modal frequencies involved in the correction. Exemplarily, for a single-section casing, N s = 6; w i represents the weight coefficient of the i-th modal frequency, and the value of this weight ranges from 0 to 1. Exemplarily, for a single-section casing, w i = 1 (i = 1, 2, 3, …, 6); f i e and f i a are the test value and simulation value of the i-th modal frequency.

[0089] In addition, s.t. is the abbreviation of'subject to', which means "constrained by" or "such that... is satisfied", and is used to describe the constraint conditions in a mathematical problem or model; x is the correction parameter of the casing; x lb and x ub are the lower and upper limits of the correction parameter, which are vectors. Exemplarily, for the model correction of the substructure, the material properties and density of the structure are used as the correction parameters, and the upper and lower limits of the correction parameters are shown in Table 2.

[0090] Table 2 Correction Parameters and Ranges of the Substructure Model

[0091] Correction parameter Range Elastic modulus E / GPa 180～210 Density ρ / kg / m3 7500～8000

[0092] Adjust the key parameters (elastic modulus, density) in the initial finite element model to make the simulation results match the test results, reduce the error between the simulation and test modal characteristics, and complete the correction of the initial finite element model to form a basic finite element model.

[0093] S103. Assemble several basic finite element models to form a finite element model of the casing connection structure, specifically including:

[0094] Import several basic finite element models into the finite element software, and use the coaxial docking method at the head and tail ends to assemble the basic finite element models of several substructures. Use the node coincidence method to represent the connection between each substructure, establish the contact model of the connection part, and perform alignment assembly on the contact models of several basic finite element models and several connection components to ensure the continuity and coordination of the interface nodes, and then form a finite element model of the casing connection structure.

[0095] Set the element properties of the contact model as the virtual material to be corrected. The virtual material property of the contact model is the elastic modulus, which corresponds to the materials of the above-mentioned substructures. Exemplarily, the elastic modulus E = 206 GPa, Poisson's ratio μ = 0.3, and density ρ = 7800 kg / m 3 .

[0096] Ensure that the assembled model is consistent with the boundary conditions and loading methods of the real structure to improve the integrity of the finite element model of the casing connection structure.

[0097] S104. Divide the finite element model of the casing connection structure into super elements, including super element structures and residual substructures, specifically including:

[0098] Obtain the connection interface of the flange connector in the finite element model of the casing connection structure;

[0099] Taking the connection interface of the flange connector as the division boundary, divide the finite element model of the casing connection structure into super elements, forming two super element structures and one or more residual substructures connecting the two super element structures;

[0100] The end of the residual substructure is sleeved with a flange connector for docking with adjacent super element structures or residual substructures, and the super element structure does not include a flange connector.

[0101] Different from the traditional method, the division of super elements is not strictly based on the part boundary, but is divided according to the connection interface of the flange connector, realizing the flexibility of representing the virtual material properties of the flange connector.

[0102] For further illustration, referring to Figure 5 , divide the casing into three components, set the super element structures at both ends as the first super element 9 and the second super element 11, and set the residual substructure as the residual substructure 10. Then, flange connectors are sleeved at both ends of the residual substructure 10, and no flange connectors are sleeved at the ends of the first super element 9 and the second super element 11.

[0103] Select the nodes at the connection interfaces of the first super element 9, the second super element 11, and the residual substructure 10 as the connection node set for simulating the connection relationship between structures; and define the degrees of freedom of the connection node set as fully connected in 6 directions, that is, allowing the free transfer of stiffness and mass in 3 translation directions and 3 rotation directions to ensure the integrity of the connection.

[0104] Although the above has been exemplarily described with the first super unit 9, the second super unit 11 and a residual sub-structure 10 as examples, however, the number of the residual sub-structures 10 in the present invention is not limited thereto. There can be various numbers of the residual sub-structures 10, such as two, three, four, etc., which is determined by the specific distribution form of the flange connectors in the casing. Those skilled in the art can comprehensively consider according to the principle of the present invention and the actual application situation, as long as the principle of the present invention can be realized.

[0105] S105. Perform modal analysis on the super unit structure and the residual sub-structure, specifically including:

[0106] Use the modal synthesis method to condense the super unit structure, obtain the mass matrix and stiffness matrix of each super unit structure, and compress a large number of degrees of freedom (from mesh generation) of the super unit structure into a finite number of degrees of freedom through modal analysis. Generate the corresponding mass matrix and stiffness matrix, significantly reducing the calculation amount while retaining a good representation of the dynamic characteristics of the overall structure.

[0107] Assemble the mass matrix and stiffness matrix of the super unit structure into the residual sub-structure for calculation file assembly;

[0108] Define the response output and result form in the calculation file, and submit it to the solver for modal analysis of the super unit structure and the residual sub-structure to obtain the theoretical frequencies and theoretical vibration modes of the super unit structure and the residual sub-structure.

[0109] S106. Assemble the super unit structure and the residual sub-structure to form a casing connection structure model, perform a modal test on the casing connection structure model, and complete the modification of the casing connection structure model in combination with the modal analysis of the super unit structure and the residual sub-structure.

[0110] Among them, in the process of assembling the super unit structure and the residual sub-structure to form a casing connection structure model;

[0111] When assembling the super unit structure and the residual sub-structure, use a torque wrench to control the pre-tightening force of the bolt connection, and the bolt tightening sequence adopts a symmetric tightening method to ensure that the connection characteristics on the flange connectors are as uniform as possible;

[0112] In the process of performing a modal test on the casing connection structure model, the measuring point positions and excitation directions of the casing connection structure model are kept consistent with the measuring point positions and excitation directions on the sub-structure.

[0113] And in the process of completing the modification of the casing connection structure model, it specifically includes:

[0114] Use a mathematical model to adjust the flange virtual material parameters in the residual sub-structure until the consistency between the modal analysis and the experimental test vibration modes is determined;

[0115] Update the casing connection structure model to complete the correction.

[0116] Among them, the modal confidence criterion is used to determine the consistency between the simulation analysis and the experimental test vibration modes. The modal confidence criterion is specifically:

[0117]

[0118] In the formula, MAC ij represents the mode similarity between the i-th experimental vibration mode and the j-th simulation vibration mode. The closer its value is to 1, the higher the similarity between the two; represents the i-th experimental vibration mode; represents the j-th simulation vibration mode; T represents the transpose operation of the vector;

[0119] Furthermore, an intelligent optimization algorithm (such as genetic algorithm, particle swarm optimization algorithm) is used to optimize the parameters of the casing connection structure model, so as to improve the accuracy of the finally output corrected finite element model.

[0120] Exemplarily, when the genetic algorithm is used for the correction of the casing connection structure model, to ensure the convergence of the model correction, the number of individuals and the population number of the genetic algorithm used for the correction of the casing connection structure model are both set to 1.5 times the corresponding quantity when the single substructure model is corrected. That is, when the mathematical model of the single substructure model correction uses the genetic algorithm to solve, the algorithm includes 30 generations of populations, and each population includes 50 individuals; the number of individuals and the population number of the casing connection structure model correction algorithm are 75 and 45 respectively, minimizing the error between the simulation and the experimental modal characteristics.

[0121] Correspondingly, referring to Figure 8 , when the adjusted objective function returns to zero, it means that convergence is achieved, the consistency between the simulation analysis and the experimental test vibration modes is achieved, and the correction of the casing connection structure model is completed.

[0122] Referring to Figure 7 , it is the flow schematic diagram of the casing connection structure model correction method based on super elements in the embodiments of the present invention Figure 2 For the casing connection structure model correction method based on super elements of the present invention, each initial finite element model is first corrected layer by layer, and then the casing connection structure finite element model is divided into super elements. Based on the casing connection structure model, a modal test is carried out, and the modal analysis of the super element structure and the residual substructure is combined; the large amount of the original overall model correction is disassembled into several steps, and by improving the accuracy of each component of the casing connection structure, the accuracy requirements of the corrected casing connection structure model are met, the requirements for computer hardware and the scale of the calculation file are reduced, and thus the correction efficiency of the corrected casing connection structure model is improved.

[0123] In addition, in the present application, by setting the model material identically, the error of model material parameters is effectively isolated; and by taking the connection interface of the flange connector as the division boundary, the error of the characterization parameters of the connection interface is reduced.

[0124] Meanwhile, when the splitting of the sub-structure corresponds to the super-element division of the finite element model of the casing connection structure, the super-element model parameters can be determined according to the correction result of the sub-structure model, and then the calculation result corresponding to the super-element is calculated. Moreover, taking this result as the known determined part, there is no need to recalculate during the correction of the connection interface parameters, which can significantly reduce the time of model correction and improve the correction efficiency.

[0125] Similarly, referring to Figure 6 , the present invention also proposes a model correction system for the casing connection structure based on super-elements, including:

[0126] A model construction unit, configured to split the casing into several sub-structures and establish the initial finite element models of the several sub-structures;

[0127] A first correction unit, configured to perform modal tests on the sub-structures and perform modal analysis on the initial finite element models, and correct the initial finite element models into basic finite element models based on the results of the modal tests and modal analysis;

[0128] A model assembly unit, configured to assemble the several basic finite element models to form a finite element model of the casing connection structure;

[0129] A model division unit, configured to perform super-element division on the finite element model of the casing connection structure, dividing it into a super-element structure and a residual sub-structure;

[0130] A model analysis unit, configured to perform modal analysis on the super-element structure and the residual sub-structure;

[0131] A second correction unit, configured to assemble the super-element structure and the residual sub-structure to form a model of the casing connection structure, perform modal tests on the model of the casing connection structure, and complete the correction of the model of the casing connection structure in combination with the modal analysis of the super-element structure and the residual sub-structure.

[0132] Among them, the model division unit is specifically configured to:

[0133] Obtain the connection interface of the flange connector in the finite element model of the casing connection structure;

[0134] Taking the connection interface of the flange connector as the division boundary, perform super-element division on the finite element model of the casing connection structure to form two super-element structures and one or more residual sub-structures connecting the two super-element structures;

[0135] The end of the residual sub-structure is sleeved with a flange connector for docking with an adjacent super-element structure or residual sub-structure.

[0136] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection, or a connection capable of mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside multiple components or the interaction relationship between multiple components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0137] Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for modifying a casing connection structure model based on a super unit, characterized in that: The following steps are involved: The casing is divided into several substructures, and initial finite element models of the substructures are established; Perform modal tests on the substructure and modal analysis on the initial finite element model, and modify the initial finite element model to become the basic finite element model based on the results of the modal tests and modal analysis; Assembling several basic finite element models to form a finite element model of the casing connection structure; The finite element model of the casing connection structure is divided into a super-unit structure and a residual sub-structure by super-unit division; Perform modal analysis on super-element structures and residual substructures; The super unit structure and the residual substructure are assembled to form a casing connection structure model. A modal test is performed on the casing connection structure model. The casing connection structure model is modified by combining the modal analysis of the super unit structure and the residual substructure.

2. The method for correcting the casing connection structure model based on super-unit according to claim 1, characterized in that: The establishment of the initial finite element models of the plurality of substructures specifically comprises the following steps: Obtain the design parameters of the casing and construct the geometric model of the substructure; The geometric model of the substructure is meshed with three-dimensional solid elements to obtain a number of finite elements, which are combined to form an initial finite element model of the substructure.

3. The method for correcting the casing connection structure model based on super-unit according to claim 1, characterized in that: Before the modal test is performed on the substructure, the following steps are included: Perform modal analysis based on the initial finite element model to obtain the modal theoretical frequency and theoretical vibration shape, and arrange the measurement point positions on the substructure according to the modal theoretical frequency and theoretical vibration shape; The measuring point positions include axial measuring points and circumferential measuring points; The number of axial measuring points at the measuring point positions is consistent with the number of axial wave peaks corresponding to the theoretical vibration mode, and the number of circumferential measuring points is consistent with the number of circumferential wave peaks corresponding to the theoretical vibration mode.

4. The method for correcting the casing connection structure model based on super-unit according to claim 1, characterized in that: The assembling of several basic finite element models to form a finite element model of the casing connection structure specifically includes: Import several basic finite element models into finite element software, use node coincidence to characterize the connection parts used to connect adjacent substructures, and establish contact models of the connection parts; Assemble several basic finite element models and contact models of several connecting parts to form a finite element model of the casing connection structure; Wherein, the unit attribute of the contact model is set as virtual material.

5. The method for modifying the casing connection structure model based on super-unit according to claim 1, characterized in that: The finite element model of the casing connection structure is divided into a super unit structure and a residual substructure, specifically including: Obtaining the connection interface of the flange connection part in the finite element model of the casing connection structure; Taking the connection interface of the flange connector as the dividing boundary, the finite element model of the casing connection structure is divided into super units to form two super unit structures and one or more residual substructures connecting the two super unit structures; The end of the residual substructure is sleeved with a flange connector for butting with an adjacent super unit structure or residual substructure.

6. The method for modifying the casing connection structure model based on super-unit according to claim 5, characterized in that: The modal analysis of the super unit structure and the residual substructure specifically includes: The modal synthesis method is used to condense the super-unit structure to obtain the mass matrix and stiffness matrix of each super-unit structure; Assemble the mass matrix and stiffness matrix of the super-element structure into the residual substructure and assemble the calculation files; Define the response output and result format in the calculation file, and submit the solver to perform modal analysis of the superunit structure and residual substructure.

7. The method for modifying a casing connection structure model based on a super unit according to claim 3, characterized in that: During the modal test on the casing connection structure model, the measuring point position and excitation direction of the casing connection structure model are kept consistent with the measuring point position and excitation direction on the substructure.

8. The method for modifying a casing connection structure model based on a super-element according to claim 1, characterized in that: The completion of the correction of the casing connection structure model specifically includes: The virtual material parameters of the flange in the residual substructure are adjusted using the mathematical model until the consistency between the modal analysis and experimental test vibration shapes is determined; Updated the receiver connection structure model to complete the correction.

9. A super-element-based casing connection structure model correction system, characterized in that: include: A model building unit, used for splitting the casing into a plurality of substructures and establishing initial finite element models of the plurality of substructures; A first correction unit is used for performing a modal test on the substructure and a modal analysis on the initial finite element model, and correcting the initial finite element model to be a basic finite element model based on the results of the modal test and the modal analysis; A model assembly unit, used for assembling a number of basic finite element models to form a finite element model of the casing connection structure; A model division unit is used to divide the finite element model of the casing connection structure into a super unit structure and a residual substructure; Model analysis unit, used to perform modal analysis on super-element structures and residual substructures; The second correction unit is used to assemble the super-unit structure and the residual substructure to form a casing connection structure model, perform modal tests on the casing connection structure model, and complete the correction of the casing connection structure model by combining the modal analysis of the super-unit structure and the residual substructure.

10. The super-element-based casing connection structure model correction system according to claim 9, characterized in that: The model division unit is specifically used for: Obtaining the connection interface of the flange connection part in the finite element model of the casing connection structure; Taking the connection interface of the flange connector as the dividing boundary, the finite element model of the casing connection structure is divided into super units to form two super unit structures and one or more residual substructures connecting the two super unit structures; The end of the residual substructure is sleeved with a flange connector for butting with an adjacent super unit structure or residual substructure.

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