Residual stress mechanical analysis method and system based on carbon fiber body structural parts

Abstract

The present invention relates to the technical field of material performance analysis, and is a residual stress mechanical analysis method and system based on a carbon fiber vehicle body structural component, comprising: performing macro-micro smooth modeling on a scanning result of a structural component; performing an edge-based smooth domain construction operation on the smooth modeling result to obtain a smooth domain matrix; constructing a stiffness matrix according to a pre-constructed initialization material constant matrix and a smooth domain matrix; and constructing a residual stress mechanical analysis method and system based on a smooth Galerkin W matrix. 2 The method comprises the following steps: using the stiffness matrix to construct the macroscopic system equilibrium equation and the microscopic system equilibrium equation, and coupling to obtain the boundary system equilibrium equation; constructing a multi-scale smooth finite element model using the system equilibrium equation; updating the multi-scale smooth finite element model according to a preset reconstruction post-processing strategy; and calculating the residual stress distribution according to the mechanical parameter data set using the multi-scale smooth finite element model. The present invention can improve the accuracy of quality control of carbon fiber structural parts.

Description

Technical Field

[0001] The present invention relates to the technical field of material performance analysis, and in particular to a residual stress mechanical analysis method and system based on carbon fiber vehicle body structural parts. Background Art

[0002] The weight of a car can be reduced by more than 50% by using carbon fiber composite materials (CFRP), which is a very impressive weight reduction effect. CFRP has become the most popular and most promising lightweight new material in the automotive industry after high-strength steel, aluminum alloy, magnesium alloy, and engineering plastics. Today, High Pressure-Resin Transfer Molding (HP-RTM) is the main technical means for the construction of carbon fiber composite materials. HP-RTM is a composite material integrated molding method that injects resin into a closed mold under high pressure to infiltrate the reinforcement material and quickly solidify it.

[0003] However, warping deformation after molding and demolding is the main defect of the HP-RTM process. Sometimes the probability of its occurrence can reach more than 70% of the total molding defects. This defect directly affects the performance indicators such as dimensional stability, strength and stiffness of the CFRP body structure, resulting in its structural function not being guaranteed.

[0004] Nowadays, many scholars at home and abroad have conducted in-depth research on the factors that cause warpage deformation after curing and demolding of composite structure during the molding process, such as curing pressure, heating rate, convective heat transfer coefficient, material properties, fiber volume fraction, ply orientation and structural form, component thickness and corner radius and mold form, and summarized the main factors affecting the warpage of CFRP body structure HP-RTM molding as follows: 1) deformation caused by the inconsistency of thermal expansion / cooling coefficient between body structure and mold; 2) deformation caused by the difference in thermal expansion coefficient in the plane and thickness direction of body structure; 3) deformation caused by unbalanced ply of body structure; 4) deformation caused by gradient change of temperature and curing in the thickness direction during curing of body structure; 5) deformation caused by chemical shrinkage during resin curing. Many factors affecting deformation cause residual stress to be generated during molding in CFRP body structure through the coupling of stress gradient and temperature gradient. The existence of residual stress is the most direct and fundamental cause of warpage deformation. Therefore, the accuracy of warpage deformation prediction depends largely on the accuracy of residual stress analysis. It is urgent to develop a new method and system for residual stress analysis of carbon fiber composite body structure with high accuracy and efficiency. Summary of the invention

[0005] The present invention provides a residual stress mechanical analysis method based on carbon fiber vehicle body structural parts, the main purpose of which is to improve the accuracy of quality control of carbon fiber structural parts.

[0006] To achieve the above object, the present invention provides a residual stress mechanical analysis method based on carbon fiber vehicle body structural parts, comprising:

[0007] Using a pre-built multi-scale scanning device, a pre-built target structural component is scanned to obtain a scanning result of the structural component, and the scanning result of the structural component is subjected to macro-micro smooth modeling to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element;

[0008] Performing edge-based smooth domain construction operations on the two-dimensional smooth finite element plate and shell elements and the three-dimensional smooth finite element body elements to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix;

[0009] Obtaining an initialization material constant matrix, and constructing a macroscopic region stiffness matrix and a microscopic region stiffness matrix according to the initialization material constant matrix, a two-dimensional smooth domain matrix, and a three-dimensional smooth domain matrix;

[0010] Based on the pre-built smooth Galerkin W 2 In the form of, using the macroscopic region stiffness matrix and the microscopic region stiffness matrix, construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation, and couple the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation to obtain the interface region system equilibrium equation;

[0011] The overall system balance equation of the target structural component is constructed by using the macroscopic system balance equation, the microscopic system balance equation and the interface system balance equation, and a multi-scale smooth finite element model of the target structural component is constructed according to the overall system balance equation;

[0012] According to a preset reconstruction post-processing strategy, a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model is performed in a microscopic region in the multi-scale smooth finite element model to obtain an updated multi-scale smooth finite element model;

[0013] A mechanical parameter data set is obtained, and the updated multi-scale smooth finite element model is used to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

[0014] Optionally, the pre-constructed target structural part is scanned by using a pre-constructed multi-scale scanning device to obtain a structural part scanning result, and the structural part scanning result is subjected to macro-micro smooth modeling to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element, including:

[0015] Using a pre-built multi-scale scanning device, respectively, to perform a scanning operation based on millimeter-level X-rays and micrometer-level X-rays on a pre-built target structural component, to obtain a millimeter-level light scanning result sequence and a micrometer-level light scanning result sequence, and using the millimeter-level light scanning result sequence and the micrometer-level light scanning result sequence as the structural component scanning result;

[0016] Discretizing the problem domain based on the structural morphology of the millimeter light scanning result sequence and the micrometer light scanning result sequence to obtain a macroscopic region, a microscopic region and an intersection region;

[0017] Using a pre-built smooth finite element modeling algorithm, two-dimensional shell modeling is performed on the millimeter light scanning results corresponding to the macroscopic area in the millimeter light scanning result sequence to obtain two-dimensional smooth finite element plate and shell elements, and three-dimensional solid modeling is performed on the micron light scanning results corresponding to the microscopic area in the micron light scanning result sequence to obtain three-dimensional smooth finite element body elements.

[0018] Optionally, the pre-constructed smooth Galerkin W 2 In the form of macroscopic region stiffness matrix and microscopic region stiffness matrix, the macroscopic region system equilibrium equation and microscopic region system equilibrium equation are constructed, including:

[0019] Based on the pre-built smooth Galerkin W 2 In the form of obtaining the strain energy characteristics between each smooth domain in the smooth domain set, a strain energy characteristic distribution is obtained;

[0020] identifying the convergence of the strain energy characteristic distribution and obtaining a non-convergence region;

[0021] When the non-convergence region exists in the strain energy characteristic distribution, the smooth domain set is stratified according to the non-convergence region to obtain a stratification result;

[0022] According to the stratification results, the macroscopic region stiffness matrix and the microscopic region stiffness matrix are constructed in batches to construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation.

[0023] Optionally, coupling the macroscopic region system balance equation and the microscopic region system balance equation to obtain the interface region system balance equation includes:

[0024] Constructing a combined multi-point constraint equation for the intersection area;

[0025] The combined multi-point constraint equation, the macroscopic system equilibrium equation and the microscopic system equilibrium equation are coupled by using a pre-constructed full Lagrangian algorithm to obtain the interface system equilibrium equation.

[0026] Optionally, the stress result reconstruction operation based on the multi-scale anisotropic material smooth finite element model is performed in the microscopic region of the multi-scale smooth finite element model according to a preset reconstruction post-processing strategy to obtain an updated multi-scale smooth finite element model, including:

[0027] obtaining a stress prediction network from the multi-scale smooth finite element model;

[0028] Obtain each smooth domain in the two-dimensional smooth finite element plate and shell element and the three-dimensional smooth finite element body element to obtain a smooth domain set;

[0029] Obtaining an assumption in a preset reconstruction post-processing strategy, wherein the assumption is that the stress value of the smooth domain is the stress value of the center point of the smooth domain;

[0030] Obtaining the smooth domain center point corresponding to each smooth domain in the smooth domain set, and calculating the stress value of each smooth domain center point using the stress prediction network according to the assumed conditions;

[0031] Using the point interpolation method in the pre-built meshless algorithm, a node set is obtained, and the stress value of the center point of each smooth domain is converted into the stress value of each node in the node set, wherein one node is shared by multiple smooth domains;

[0032] Obtaining the smooth domain area of ​​each node in the node set to obtain a smooth domain area set, and performing weighted average calculation on the stress value of each node in the node set based on the smooth domain area set to obtain a post-processing node stress value set;

[0033] According to the post-processing node stress value set, the stress value of each smooth domain center point in the stress prediction network is updated to obtain an updated stress prediction network, and according to the updated stress prediction network, an updated multi-scale smooth finite element model is obtained.

[0034] Optionally, the obtaining of a mechanical parameter data set includes:

[0035] Obtaining mechanical parameters of the carbon fiber composite material matrix and fibers of the target structural component to obtain basic mechanical parameters;

[0036] Using a pre-built high-precision CT scanning device, the fiber volume rate distribution of different parts of the target structural component in the thickness direction is measured to obtain the fiber volume rate;

[0037] The pre-constructed micromechanical model is used to predict the basic mechanical parameters and fiber volume fraction to obtain a mechanical parameter data set.

[0038] Optionally, after obtaining the residual stress distribution, the method further includes:

[0039] Predicting warpage deformation using the residual stress distribution to obtain a predicted warpage amount;

[0040] Using a pre-built experimental measurement algorithm, the target structural component is measured to obtain an experimental measurement result;

[0041] Calculating the difference between the predicted warpage amount and the experimental measurement result;

[0042] Determine whether the difference is greater than a preset qualified threshold;

[0043] When the difference is greater than the qualified threshold, model parameter training is performed on the updated multi-scale smooth finite element model to obtain an optimized updated multi-scale smooth finite element model.

[0044] Optionally, the use of the macroscopic region system balance equation, the microscopic region system balance equation and the interface region system balance equation to construct the total system balance equation of the target structural component includes:

[0045] Obtaining the positional relationship between the macroscopic region, the microscopic region and the junction region;

[0046] According to the positional relationship, parameter range constraints are imposed on the macroscopic region system balance equation, the microscopic region system balance equation and the boundary region system balance equation to obtain the total system balance equation.

[0047] Optionally, before using the pre-built smooth finite element modeling algorithm, the method further includes:

[0048] Determining the region type of the target structural component;

[0049] When the region type is the macro region, the smooth finite element modeling algorithm is executed using a pre-constructed quadrilateral-triangle hybrid network;

[0050] When the region type is the mesoscopic region, the smooth finite element modeling algorithm is executed using pre-constructed unstructured three-dimensional tetrahedral elements.

[0051] To achieve the above object, the present invention also provides a residual stress mechanical analysis system based on carbon fiber vehicle body structural parts, comprising:

[0052] A smooth domain construction module is used to scan a pre-constructed target structural part by using a pre-constructed multi-scale scanning device to obtain a scanning result of the structural part, and to perform macro-micro smooth modeling on the scanning result of the structural part to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element, and to perform an edge-based smooth domain construction operation on the two-dimensional smooth finite element plate and shell element and the three-dimensional smooth finite element body element to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix;

[0053] The structural component model building module is used to obtain the initial material constant matrix, and to construct the macroscopic region stiffness matrix and the microscopic region stiffness matrix according to the initial material constant matrix, the two-dimensional smooth domain matrix and the three-dimensional smooth domain matrix, and to construct the smooth Galerkin W 2 The macroscopic region stiffness matrix and the microscopic region stiffness matrix are used to construct the macroscopic region system balance equation and the microscopic region system balance equation, and the macroscopic region system balance equation and the microscopic region system balance equation are coupled to obtain the interface region system balance equation; the total system balance equation of the target structural component is constructed by using the macroscopic region system balance equation, the microscopic region system balance equation and the interface region system balance equation, and a multi-scale smooth finite element model of the target structural component is constructed according to the total system balance equation;

[0054] A stress reconstruction module, used to perform a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model in a microscopic region of the multi-scale smooth finite element model according to a preset reconstruction post-processing strategy, to obtain an updated multi-scale smooth finite element model;

[0055] The warpage prediction module is used to obtain a mechanical parameter data set, and use the updated multi-scale smooth finite element model to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

[0056] In order to solve the above problem, the present invention further provides an electronic device, the electronic device comprising:

[0057] A memory storing at least one instruction;

[0058] The processor executes the instructions stored in the memory to implement the above-mentioned residual stress mechanical analysis method based on carbon fiber body structural parts.

[0059] In order to solve the above problems, the present invention also provides a computer-readable storage medium, in which at least one instruction is stored. The at least one instruction is executed by a processor in an electronic device to implement the above-mentioned residual stress mechanical analysis method based on carbon fiber body structural parts.

[0060] The present invention solves the problem described in the background technology. The present invention first scans the target structural parts from the millimeter level and the micrometer level through multi-scale scanning to obtain observation results at different scales, and divides the large area of ​​relatively flat or slightly curved parts into macroscopic areas, and divides the corner parts into microscopic areas. The performance analysis of the macroscopic area is constructed by constructing a two-dimensional smooth finite element plate and shell element through the millimeter-level scanning results, and the performance analysis of the microscopic area is constructed by constructing a three-dimensional smooth finite element body element through the micrometer-level scanning results; according to the smooth Galerkin W2 The system equilibrium equations of the macroscopic region and the microscopic region are constructed in the form of the multi-scale smooth finite element model. 2 The form combines the numerical solution method of smooth domain construction and weak form theory, reduces the requirement for the function regularity of the solution stress value, and introduces a smooth operator to improve the continuity of the solution, making it more outstanding in complex mechanical problems. The multi-scale smooth finite element model can calculate the stress results efficiently and accurately; the stress results are processed by the reconstruction post-processing strategy to obtain more accurate residual stress, thereby more accurately calculating and predicting the warpage, wherein the reconstruction post-processing strategy can further improve the accuracy of the stress results. Therefore, the present invention can improve the accuracy of quality control of carbon fiber structural parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 A schematic flow chart of a residual stress mechanical analysis method based on a carbon fiber vehicle body structural component provided by an embodiment of the present invention;

[0062] Figure 2 A schematic diagram of an embodiment of a residual stress mechanical analysis method based on a carbon fiber vehicle body structural component provided by an embodiment of the present invention;

[0063] Figure 3 An overall schematic diagram of model construction and analysis in a residual stress mechanical analysis method based on a carbon fiber vehicle body structural component provided by an embodiment of the present invention;

[0064] Figure 4 A functional module diagram of a residual stress mechanical analysis system based on a carbon fiber vehicle body structural component provided by an embodiment of the present invention;

[0065] Figure 5 A schematic structural diagram of an electronic device for implementing the residual stress mechanical analysis method based on carbon fiber vehicle body structural parts provided by an embodiment of the present invention.

[0066] Description of reference numerals:

[0067] 1. Electronic device; 10. Processor; 11. Memory; 12. Bus.

[0068] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0069] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0070] The embodiment of the present application provides a residual stress mechanical analysis method based on carbon fiber body structural parts. The execution subject of the residual stress mechanical analysis method based on carbon fiber body structural parts includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided by the embodiment of the present application. In other words, the residual stress mechanical analysis method based on carbon fiber body structural parts can be executed by software or hardware installed on a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc.

[0071] Reference Figure 1 FIG. 1 is a flow chart of a residual stress mechanical analysis method based on a carbon fiber vehicle body structural component provided by an embodiment of the present invention. In this embodiment, the residual stress mechanical analysis method based on a carbon fiber vehicle body structural component includes:

[0072] S1. Use a pre-constructed multi-scale scanning device to scan a pre-constructed target structural part to obtain a scanning result of the structural part, and perform macro-micro smooth modeling on the scanning result of the structural part to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element.

[0073] The multi-scale scanning device refers to a device that can modulate multiple types of light to scan a target structural part.

[0074] The target structural part refers to a composite material component formed by high-pressure resin transfer molding. The target structural part needs to be warped before being put into use. The accuracy of the prediction of the warping deformation depends largely on the accuracy of the residual stress calculation.

[0075] The smoothness in the smooth modeling refers to smoothing the displacement field, stress field or strain field in the traditional finite element method, so as to construct a continuous, more flexible and smooth solution field, avoiding the discontinuity or numerical error problems caused by meshing in the traditional finite element method.

[0076] In detail, in the embodiment of the present invention, the pre-constructed multi-scale scanning device is used to scan the pre-constructed target structural part to obtain the structural part scanning result, and the structural part scanning result is subjected to macro-micro smooth modeling to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element, including:

[0077] Using a pre-built multi-scale scanning device, respectively, to perform a scanning operation based on millimeter-level X-rays and micrometer-level X-rays on a pre-built target structural component, to obtain a millimeter-level light scanning result sequence and a micrometer-level light scanning result sequence, and using the millimeter-level light scanning result sequence and the micrometer-level light scanning result sequence as the structural component scanning result;

[0078] Discretizing the problem domain based on the structural morphology of the millimeter light scanning result sequence and the micrometer light scanning result sequence to obtain a macroscopic region, a microscopic region and an intersection region;

[0079] Using a pre-built smooth finite element modeling algorithm, two-dimensional shell modeling is performed on the millimeter light scanning results corresponding to the macroscopic area in the millimeter light scanning result sequence to obtain two-dimensional smooth finite element plate and shell elements, and three-dimensional solid modeling is performed on the micron light scanning results corresponding to the microscopic area in the micron light scanning result sequence to obtain three-dimensional smooth finite element body elements.

[0080] The problem domain in the problem domain discretization refers to the set of things, knowledge and backgrounds directly related to a problem when solving it. It defines the scope, environment and context of the problem and is the area that people need to understand and focus on in order to solve a specific problem.

[0081] Wherein, the smooth finite element modeling algorithm is the smooth modeling process mentioned above.

[0082] Specifically, in an embodiment of the present invention, the multi-scale scanning device includes two types of X-rays: millimeter-level and micron-level.

[0083] Specifically, in the embodiment of the present invention, the target structural part is a carbon fiber structural part on a car, such as a rear wing, a door panel, etc.

[0084] Specifically, the carbon fiber body structure in the present invention is mainly based on a plate-shell structure. In addition to a large area of ​​relatively flat or slightly curved parts, most of these plate-shell structures have many corners and flanges. Although the range of the corner part is usually not large, it contributes greatly to the warpage. This is because the slight angle change of the corner part has a large leverage effect.

[0085] Therefore, reference Figure 2 As shown in the figure, the present invention divides the corner into microscopic regions, and subdivides the regions using three-dimensional smooth finite element body elements. Other large areas of relatively flat or slightly curved parts (for example, the curvature is less than a preset value) are divided into macroscopic regions, which are simplified and reduced in dimension using plate and shell theory in the thickness dimension, and can be roughly divided using two-dimensional smooth finite element plate and shell elements.

[0086] The present invention adopts such a multi-scale model to ensure that the detailed areas of key corners are not missed and the overall smooth finite element model is not too large.

[0087] In detail, in the embodiment of the present invention, before using the pre-built smooth finite element modeling algorithm, the method further includes:

[0088] Determining the region type of the target structural component;

[0089] When the region type is the macro region, the smooth finite element modeling algorithm is executed using a pre-constructed quadrilateral-triangle hybrid network;

[0090] When the region type is the mesoscopic region, the smooth finite element modeling algorithm is executed using pre-constructed unstructured three-dimensional tetrahedral elements.

[0091] Specifically, in the embodiment of the present invention, since the geometric shapes at the corners are usually very complex, we will use unstructured three-dimensional tetrahedron elements. In the macro region, we will use a hybrid grid in the form of quadrilaterals and triangles with quadrilaterals as the main form. In this way, meshing can be basically performed automatically.

[0092] S2. Perform edge-based smooth domain construction operations on the two-dimensional smooth finite element plate and shell elements and the three-dimensional smooth finite element body elements to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix.

[0093] The edge-based smooth domain construction operation refers to defining and constructing a smooth domain based on the edge of the finite element unit in the smoothed finite element method (SFEM) so as to smooth the strain or stress field in these local areas. The goal of this operation is to eliminate discontinuities between units and improve calculation accuracy and numerical stability.

[0094] Specifically, refer to Figure 3 As shown, in the embodiment of the present invention, the edge-based smooth domain construction operation includes first processing the smooth strain matrix construction and the material constant matrix construction. The present invention converts the above-constructed smooth domain model (two-dimensional smooth finite element plate and shell elements and three-dimensional smooth finite element body elements) into a strain matrix that is convenient for numerical calculation, and obtains a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix.

[0095] Specifically, in the embodiment of the present invention, the calculation is performed according to the following regional stiffness calculation formula:

[0096] Among them, in the embodiment of the present invention, the three-dimensional smooth finite element body element is similar to the two-dimensional smooth finite element plate and shell element. Since the amount of macro calculation data is small, the present invention will be described later using the two-dimensional smooth finite element plate and shell element as an example.

[0097] The two-dimensional smooth finite element plate and shell element is expressed as:

[0098] Plane stress problems:

[0099] ;

[0100] Plane strain problems:

[0101] ;

[0102] In the formula, represents a two-dimensional smooth finite element plate and shell element, represents the elastic modulus, represents Poisson's ratio.

[0103] It should be known that the smooth domain matrix is ​​the core of the smooth finite element method, which is used to describe the variable distribution and integration range in the smooth domain. The division method of the smooth domain is different from the unit division of the traditional finite element. Its main idea is to realize the construction of the smooth field through the integration in the smooth domain.

[0104] Specifically, in the embodiment of the present invention, the smooth domain of the two-dimensional smooth finite element plate and shell element is usually divided into sub-regions generated by the center point or vertex of each unit.

[0105] Assuming a 2D quadrilateral element e, its smooth domain can be generated by the following steps:

[0106] 1) Cell division: Use cell center points or vertices to divide the cell into several sub-regions (such as triangles or quadrilaterals).

[0107] 2) Integration weight in smooth domain: When performing area integration on a smooth domain, the integration weight is distributed through area coordinates or shape function interpolation.

[0108] 3) Smooth strain matrix construction:

[0109] Compute the strain within each smooth domain:

[0110] ;

[0111] In the formula, represents the smooth domain area, represents the two-dimensional smooth finite element plate and shell element, represents a two-dimensional smooth domain matrix, represents the integral over the area of ​​the smooth domain.

[0112] Similarly, the three-dimensional smooth domain matrix can be calculated.

[0113] S3. Obtain an initialization material constant matrix, and construct a macroscopic region stiffness matrix and a microscopic region stiffness matrix according to the initialization material constant matrix, a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix.

[0114] The initialization material constant matrix is ​​a matrix in numerical form, which is used to display the mechanical parameters of the carbon fiber matrix and fiber of the target structural part. However, the mechanical parameters have not yet been obtained, and the initialization values ​​can be used instead, and they will be assigned later.

[0115] Furthermore, in the embodiment of the present invention, the macroscopic region stiffness matrix and the microscopic region stiffness matrix can be calculated according to the basic formula of the stiffness matrix, wherein the basic formula of the stiffness matrix is ​​expressed as:

[0116] ;

[0117] In the formula, represents the macroscopic regional stiffness matrix, represents the total number of smooth domains, represents a smooth domain, represents the area of ​​a smooth domain, represents a two-dimensional smooth domain matrix, represents the transpose of the 2D smooth domain matrix, represents the initialization material constant matrix.

[0118] S4, according to the pre-constructed smooth Galerkin W 2 The macroscopic region system equilibrium equation and the microscopic region system equilibrium equation are constructed by using the macroscopic region stiffness matrix and the microscopic region stiffness matrix, and the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation are coupled to obtain the interface region system equilibrium equation.

[0119] Wherein, the smooth Galerkin W 2 The form is an improved numerical analysis method, which is an extension of finite element analysis (FEM). It optimizes the calculation accuracy and efficiency of the traditional Galerkin method by introducing the concept of smooth stress-strain field, and is particularly suitable for solving complex problems.

[0120] In detail, in the embodiment of the present invention, the pre-constructed smooth Galerkin W 2 In the form of macroscopic region stiffness matrix and microscopic region stiffness matrix, the macroscopic region system equilibrium equation and microscopic region system equilibrium equation are constructed, including:

[0121] Based on the pre-built smooth Galerkin W2 In the form of obtaining the strain energy characteristics between each smooth domain in the smooth domain set, a strain energy characteristic distribution is obtained;

[0122] identifying the convergence of the strain energy characteristic distribution and obtaining a non-convergence region;

[0123] When the non-convergence region exists in the strain energy characteristic distribution, the smooth domain set is stratified according to the non-convergence region to obtain a stratification result;

[0124] According to the stratification results, the macroscopic region stiffness matrix and the microscopic region stiffness matrix are constructed in batches to construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation.

[0125] The strain energy characteristic refers to the characteristic of elastic potential energy stored in a material or structure due to deformation when subjected to an external load, and reflects the elastic behavior of the material or structure in terms of mechanical properties.

[0126] The convergence of the strain energy characteristics refers to whether the calculated strain energy value gradually approaches the theoretical exact solution (true value) of the problem when the mesh division (number of elements) is gradually refined in numerical methods (such as the finite element method, smoothed finite element method, etc.). It is a standard for measuring the accuracy and reliability of numerical methods.

[0127] Specifically, in the embodiment of the present invention, when establishing an edge-based smooth domain in a microscopic region, it is necessary to process the interface between composite material layers.

[0128] In the embodiment of the present invention, reference Figure 3 As shown, first based on the smooth Galerkin W 2 In this way, the influence of material discontinuities on the convergence characteristics of strain energy is analyzed. If, in theory, its convergence characteristics can be guaranteed, the generation of edge smooth domains in the microscopic area can be carried out as a whole. Otherwise, it will be carried out in layers, that is, a smooth modeling is generated separately for each layer. On the other hand, since two-dimensional smooth finite element plate and shell elements are used in the macroscopic area, its smooth domain can be established as a whole.

[0129] Specific, smooth Galerkin W 2 The form is an improvement on the traditional Galerkin method, which usually introduces a displacement function and a test function based on a smooth operator for smooth integration. Its basic form is:

[0130] ;

[0131] In the formula, represents the computational domain of the macro region, Represents the external force vector (the sum of body force, surface force or node concentrated force).

[0132] Furthermore, the macroscopic system equilibrium equation is based on the principle of virtual work or W 2 The form can be written as:

[0133] ;

[0134] In the formula, represents the external force vector in the macro region, represents the unknown displacement vector in the macro region.

[0135] Then the microscopic regional stiffness matrix can be obtained:

[0136] ;

[0137] In the formula, represents the microscopic region stiffness matrix, represents the external force vector in the microscopic region, represents the unknown displacement vector in the mesoscopic region.

[0138] Wherein, the external force vector is the sum of body force, surface force or node concentrated force.

[0139] The unknown displacement vector refers to a mathematical vector that is determined by solving equations in mechanics or structural analysis and describes the displacement of each point in a structure or object. It is usually an important variable in the fields of finite element method (FEM), structural analysis, deformation research, etc.

[0140] In detail, in the embodiment of the present invention, the macroscopic system balance equation and the microscopic system balance equation are coupled to obtain the boundary system balance equation, including:

[0141] Constructing a combined multi-point constraint equation for the intersection area;

[0142] The combined multi-point constraint equation, the macroscopic system equilibrium equation and the microscopic system equilibrium equation are coupled by using a pre-constructed full Lagrangian algorithm to obtain the interface system equilibrium equation.

[0143] The combined multi-point constraint equation (MPC) is a mathematical method in numerical analysis (such as finite element analysis) and is used to describe the linear or nonlinear dependency relationship between multiple nodes or degrees of freedom.

[0144] The total Lagrangian formulation is a commonly used method in nonlinear finite element analysis, and is particularly suitable for large deformation problems and nonlinear mechanical analysis.

[0145] The coupling refers to connecting two or more physical systems or regions through mathematical or physical methods so that they can interact with each other and solve problems together, thereby achieving coordination of the overall system.

[0146] Specifically, in the embodiment of the present invention, the combined multi-point constraint equation is expressed as:

[0147] ;

[0148] In the formula, represents the degree of freedom vector of the boundary region, and Form a combined constraint matrix.

[0149] Then, coupling is performed according to the full Lagrangian algorithm to obtain the equilibrium equation of the interface system:

[0150] ;

[0151] In the formula, represents the Lagrange multiplier, and Represents the transpose of the combined constraint matrix.

[0152] S5. Use the macroscopic region system balance equation, the microscopic region system balance equation and the interface region system balance equation to construct the total system balance equation of the target structural component, and construct a multi-scale smooth finite element model of the target structural component based on the total system balance equation.

[0153] In detail, in the embodiment of the present invention, the use of the macroscopic system balance equation, the microscopic system balance equation and the interface system balance equation to construct the total system balance equation of the target structural component includes:

[0154] Obtaining the positional relationship between the macroscopic region, the microscopic region and the junction region;

[0155] According to the positional relationship, parameter range constraints are imposed on the macroscopic region system balance equation, the microscopic region system balance equation and the boundary region system balance equation to obtain the total system balance equation.

[0156] The positional relationship refers to dividing each area by the coordinates of the lower left corner and the upper right corner of the area, for example Figure 2 In the figure, the lower left corner of the body structure is (0, 0), and other areas can be marked by millimeters or microns. For example, the macro area in the lower left corner is represented by [(0, 0), (1, 1)], and the micro area in the middle may be represented by [(1, 0), (3, 3)].

[0157] In the embodiment of the present invention, the formula is segmented by two coordinate values ​​xy to obtain the overall system balance equation. Figure 2 As shown above, if the macroscopic area in the lower left corner is represented as [(0, 0), (1, 1)], and the microscopic area in the middle may be represented as [(1, 0), (3, 3)], then Figure 2 Each area is limited to , .

[0158] Then the overall system balance equation can be obtained:

[0159] ;

[0160] Furthermore, in an embodiment of the present invention, if the overall system equilibrium equation can express the stress performance of the target structural component, it can be used as the core network of the model for predicting stress, and then equipped with a neural network structure to be trained. By training with samples, a multi-scale smooth finite element model can be obtained.

[0161] S6. According to a preset reconstruction post-processing strategy, a stress result reconstruction operation based on the multi-scale anisotropic material smooth finite element model is performed in the microscopic region of the multi-scale smooth finite element model to obtain an updated multi-scale smooth finite element model.

[0162] The post-reconstruction processing strategy refers to adjusting the stress results to improve the accuracy of the stress results.

[0163] In detail, in an embodiment of the present invention, the stress result reconstruction operation based on the multi-scale anisotropic material smooth finite element model is performed in the microscopic region of the multi-scale smooth finite element model according to the preset reconstruction post-processing strategy to obtain an updated multi-scale smooth finite element model, including:

[0164] obtaining a stress prediction network from the multi-scale smooth finite element model;

[0165] Obtain each smooth domain in the two-dimensional smooth finite element plate and shell element and the three-dimensional smooth finite element body element to obtain a smooth domain set;

[0166] Obtaining an assumption in a preset reconstruction post-processing strategy, wherein the assumption is that the stress value of the smooth domain is the stress value of the center point of the smooth domain;

[0167] Obtaining the smooth domain center point corresponding to each smooth domain in the smooth domain set, and calculating the stress value of each smooth domain center point using the stress prediction network according to the assumed conditions;

[0168] Using the point interpolation method in the pre-built meshless algorithm, a node set is obtained, and the stress value of the center point of each smooth domain is converted into the stress value of each node in the node set, wherein one node is shared by multiple smooth domains;

[0169] Obtaining the smooth domain area of ​​each node in the node set to obtain a smooth domain area set, and performing weighted average calculation on the stress value of each node in the node set based on the smooth domain area set to obtain a post-processing node stress value set;

[0170] According to the post-processing node stress value set, the stress value of each smooth domain center point in the stress prediction network is updated to obtain an updated stress prediction network, and according to the updated stress prediction network, an updated multi-scale smooth finite element model is obtained.

[0171] The stress prediction network refers to a neural network that understands the mechanical properties of composite materials based on the overall system balance equation, and then predicts the stress of the material based on the existing structure and material information.

[0172] The smoothing domain is a region in which the smoothing technology is applied based on a finite element unit or a local area.

[0173] The nodes are the locations where variables are defined in the finite element or meshless method. Variables (such as displacements, stresses, etc.) are usually solved at these nodes. The location of the nodes determines the accuracy and resolvability of the entire discretized model. A node can be within the range of multiple smooth domains, because smooth domains may partially overlap in definition.

[0174] The transformation process is performed using an interpolation method.

[0175] The updating refers to substituting the output layer for generating the center point of the smooth domain into the mathematical relationship between the stress value of the node and the stress value of the center point of the smooth domain.

[0176] It should be known that according to the experience gained from the well-known conventional finite element analysis, "post-processing" of stress results plays a vital role in improving the accuracy of stress results. Existing literature has found that similar post-processing of stress results also plays an important role in improving the accuracy of stress results of smooth finite elements. This is especially important for stress analysis in the microscopic area.

[0177] Therefore, in the embodiment of the present invention, it is first assumed that the stress value of the smooth domain is the stress value of the center point of the smooth domain. Then, the stress of the center point of the smooth domain is inserted at the node by the "point interpolation" method commonly used in the meshless method, and then the inserted node stress is area-weighted averaged to obtain the final node stress value. This meticulous work will further improve the accuracy of the stress results of the smooth finite element.

[0178] In the embodiment of the present invention, the stress result reconstruction operation is a parameter-fixed operation, and the parameters of the output layer in the stress prediction network can be directly modified to obtain an updated stress prediction network, and then to obtain an updated multi-scale smooth finite element model.

[0179] S7. Acquire a mechanical parameter data set, and use the updated multi-scale smooth finite element model to calculate the residual stress of the target structural component according to the mechanical parameter data set to obtain the residual stress distribution.

[0180] The mechanical parameter data set refers to the mechanical parameters and fiber volume fraction of carbon fiber composite materials.

[0181] In detail, in an embodiment of the present invention, the step of obtaining a mechanical parameter data set includes:

[0182] Obtaining mechanical parameters of the carbon fiber composite material matrix and fibers of the target structural component to obtain basic mechanical parameters;

[0183] Using a pre-built high-precision CT scanning device, the fiber volume rate distribution of different parts of the target structural component in the thickness direction is measured to obtain the fiber volume rate;

[0184] The pre-constructed micromechanical model is used to predict the basic mechanical parameters and fiber volume fraction to obtain a mechanical parameter data set.

[0185] The mechanical parameters may include elastic modulus, tensile strength, Poisson's ratio, density, anisotropic properties (such as longitudinal elastic modulus, transverse tensile strength, etc.) and thermal expansion coefficient, etc.

[0186] The high-precision computed tomography (HPCT) scanning device is an advanced industrial or medical imaging device that can scan objects or human bodies through X-rays and use computer technology to generate high-resolution three-dimensional images or slice images. Its core features are high resolution and high precision of imaging, which can be used to detect tiny structures, defects or perform precise measurements.

[0187] Specifically, in the embodiment of the present invention, the mechanical parameters of the carbon fiber composite material matrix and the fiber can be obtained through a material company with which a cooperative relationship is established. Then, the distribution of the fiber volume rate of different parts of the target structural part in the thickness direction is measured using a high-precision CT scanning device of a certain engineering college to obtain the fiber volume rate.

[0188] Then, a microscopic mechanical model, such as an SBS model, is used to predict the fiber volume fraction and mechanical parameters to obtain the mechanical parameter data set.

[0189] In an embodiment of the present invention, after obtaining the mechanical parameter data set, the mechanical parameter data set can be used to replace the above-mentioned initialization material constant matrix, thereby achieving accurate prediction of residual stress.

[0190] Furthermore, in the embodiment of the present invention, a network model that has learned the mapping relationship between stress and warping deformation may be used for prediction to obtain a predicted warping amount.

[0191] In detail, in the embodiment of the present invention, after obtaining the residual stress distribution, the method further includes:

[0192] Predicting warpage deformation using the residual stress distribution to obtain a predicted warpage amount;

[0193] Using a pre-built experimental measurement algorithm, the target structural component is measured to obtain an experimental measurement result;

[0194] Calculating the difference between the predicted warpage amount and the experimental measurement result;

[0195] Determine whether the difference is greater than a preset qualified threshold;

[0196] When the difference is greater than the qualified threshold, model parameter training is performed on the updated multi-scale smooth finite element model to obtain an optimized updated multi-scale smooth finite element model.

[0197] The experimental measurement algorithm refers to the result produced by conducting experiments using a detection instrument.

[0198] Specifically, in an embodiment of the present invention, a neural network that has learned the mapping relationship between stress and warping deformation can be used to predict the warping amount and then calculate the difference between the experimental measurement result and the predicted warping amount. By comparing the difference with a preset qualified threshold (for example, 0.1), when the difference is greater than 0.1, it indicates that the calculation accuracy of the residual stress distribution is low and retraining is required to obtain an optimized updated multi-scale smooth finite element model.

[0199] The present invention solves the problem described in the background technology. The present invention first scans the target structural parts from the millimeter level and the micrometer level through multi-scale scanning to obtain observation results at different scales, and divides the large area of ​​relatively flat or slightly curved parts into macroscopic areas, and divides the corner parts into microscopic areas. The performance analysis of the macroscopic area is constructed by constructing a two-dimensional smooth finite element plate and shell element through the millimeter-level scanning results, and the performance analysis of the microscopic area is constructed by constructing a three-dimensional smooth finite element body element through the micrometer-level scanning results; according to the smooth Galerkin W 2 The system equilibrium equations of the macroscopic region and the microscopic region are constructed in the form of the multi-scale smooth finite element model. 2 The form combines the numerical solution method of smooth domain construction and weak form theory, reduces the requirement for the function regularity of the solution stress value, and introduces a smooth operator to improve the continuity of the solution, making it more outstanding in complex mechanical problems. The multi-scale smooth finite element model can calculate the stress results efficiently and accurately; the stress results are processed by the reconstruction post-processing strategy to obtain more accurate residual stress, thereby more accurately calculating and predicting the warpage, wherein the reconstruction post-processing strategy can further improve the accuracy of the stress results. Therefore, the present invention can improve the accuracy of quality control of carbon fiber structural parts.

[0200] like Figure 4 , which is a functional module diagram of a residual stress mechanical analysis system based on carbon fiber vehicle body structural parts provided by an embodiment of the present invention.

[0201] The residual stress mechanical analysis system 100 based on carbon fiber body structural parts of the present invention can be installed in an electronic device. According to the functions implemented, the residual stress mechanical analysis system 100 based on carbon fiber body structural parts can include a smooth domain construction module 101, a structural part model construction module 102, a stress reconstruction module 103 and a warpage prediction module 104. The module of the present invention can also be called a unit, which refers to a series of computer program segments that can be executed by an electronic device processor and can complete fixed functions, which are stored in the memory of the electronic device.

[0202] The smooth domain construction module 101 is used to scan the pre-constructed target structural part by using the pre-constructed multi-scale scanning device to obtain the structural part scanning result, and to perform macro-micro smooth modeling on the structural part scanning result to obtain two-dimensional smooth finite element plate and shell elements and three-dimensional smooth finite element body elements, and to perform edge-based smooth domain construction operation on the two-dimensional smooth finite element plate and shell elements and the three-dimensional smooth finite element body elements to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix;

[0203] The structural component model building module 102 is used to obtain an initial material constant matrix, and to build a macroscopic region stiffness matrix and a microscopic region stiffness matrix according to the initial material constant matrix, a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix, and to build a smooth Galerkin W matrix according to the pre-built smooth Galerkin W matrix. 2 The macroscopic region stiffness matrix and the microscopic region stiffness matrix are used to construct the macroscopic region system balance equation and the microscopic region system balance equation, and the macroscopic region system balance equation and the microscopic region system balance equation are coupled to obtain the interface region system balance equation; the macroscopic region system balance equation, the microscopic region system balance equation and the interface region system balance equation are used to construct the total system balance equation of the target structural component, and according to the total system balance equation, a multi-scale smooth finite element model of the target structural component is constructed;

[0204] The stress reconstruction module 103 is used to perform a stress result reconstruction operation based on the multi-scale anisotropic material smooth finite element model in the microscopic region of the multi-scale smooth finite element model according to a preset reconstruction post-processing strategy to obtain an updated multi-scale smooth finite element model;

[0205] The warpage prediction module 104 is used to obtain a mechanical parameter data set, and use the updated multi-scale smooth finite element model to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

[0206] In detail, the modules in the residual stress mechanical analysis system 100 based on carbon fiber vehicle body structural parts in the embodiment of the present invention are used in the same manner as described above. Figure 1 The same technical means are used as the residual stress mechanical analysis method based on carbon fiber body structural parts described in, and can produce the same technical effects, so they will not be repeated here.

[0207] like Figure 5 FIG. 1 is a schematic diagram of the structure of an electronic device for implementing a residual stress mechanical analysis method based on a carbon fiber vehicle body structural component provided by an embodiment of the present invention.

[0208] The electronic device 1 may include a processor 10, a memory 11 and a bus 12, and may also include a computer program stored in the memory 11 and executable on the processor 10, such as a residual stress mechanical analysis method program based on carbon fiber vehicle body structural parts.

[0209] The memory 11 includes at least one type of readable storage medium, and the readable storage medium includes a flash memory, a mobile hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory, etc.), a magnetic memory, a disk, an optical disk, etc. In some embodiments, the memory 11 may be an internal storage unit of the electronic device 1, such as a mobile hard disk of the electronic device 1. In other embodiments, the memory 11 may also be an external storage device of the electronic device 1, such as a plug-in mobile hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (SecureDigital, SD) card, a flash card (Flash Card), etc. equipped on the electronic device 1. Further, the memory 11 also includes an internal storage unit of the electronic device 1 and an external storage device. The memory 11 can not only be used to store application software and various types of data installed in the electronic device 1, such as the code of the residual stress mechanical analysis method program based on carbon fiber body structural parts, but also can be used to temporarily store data that has been output or is to be output.

[0210] The processor 10 may be composed of an integrated circuit in some embodiments, for example, a single packaged integrated circuit, or a plurality of packaged integrated circuits with the same or different functions, including one or more central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and combinations of various control chips, etc. The processor 10 is the control core (Control Unit) of the electronic device, and uses various interfaces and lines to connect various components of the entire electronic device, and executes or executes programs or modules stored in the memory 11 (for example, a residual stress mechanical analysis method program based on carbon fiber body structural parts, etc.), and calls data stored in the memory 11 to execute various functions of the electronic device 1 and process data.

[0211] The bus 12 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus 12 may be divided into an address bus, a data bus, a control bus, etc. The bus 12 is configured to realize connection and communication between the memory 11 and at least one processor 10, etc.

[0212] Figure 5 Only an electronic device with components is shown, and those skilled in the art will understand that Figure 5The structure shown does not constitute a limitation on the electronic device 1, and may include fewer or more components than shown in the figure, or combine certain components, or arrange the components differently.

[0213] For example, although not shown, the electronic device 1 may also include a power source (such as a battery) for supplying power to various components. Preferably, the power source may be logically connected to the at least one processor 10 through a power management device, so that the power management device can realize functions such as charging management, discharging management, and power consumption management. The power source may also include one or more DC or AC power sources, recharging devices, power failure detection circuits, power converters or inverters, power status indicators, and other arbitrary components. The electronic device 1 may also include a variety of sensors, Bluetooth modules, Wi-Fi modules, etc., which will not be repeated here.

[0214] Furthermore, the electronic device 1 may also include a network interface. Optionally, the network interface may include a wired interface and / or a wireless interface (such as a WI-FI interface, a Bluetooth interface, etc.), which is generally used to establish a communication connection between the electronic device 1 and other electronic devices.

[0215] Optionally, the electronic device 1 may further include a user interface, which may be a display, an input unit (such as a keyboard), or a standard wired interface or a wireless interface. Optionally, in some embodiments, the display may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, and an OLED (Organic Light-Emitting Diode) touch device. The display may also be appropriately referred to as a display screen or a display unit, which is used to display information processed in the electronic device 1 and to display a visual user interface.

[0216] The residual stress mechanical analysis method program based on carbon fiber vehicle body structural parts stored in the memory 11 of the electronic device 1 is a combination of multiple instructions. When running in the processor 10, it can achieve:

[0217] Using a pre-built multi-scale scanning device, a pre-built target structural component is scanned to obtain a scanning result of the structural component, and the scanning result of the structural component is subjected to macro-micro smooth modeling to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element;

[0218] Performing edge-based smooth domain construction operations on the two-dimensional smooth finite element plate and shell elements and the three-dimensional smooth finite element body elements to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix;

[0219] Obtaining an initialization material constant matrix, and constructing a macroscopic region stiffness matrix and a microscopic region stiffness matrix according to the initialization material constant matrix, a two-dimensional smooth domain matrix, and a three-dimensional smooth domain matrix;

[0220] Based on the pre-built smooth Galerkin W 2 In the form of, using the macroscopic region stiffness matrix and the microscopic region stiffness matrix, construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation, and couple the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation to obtain the interface region system equilibrium equation;

[0221] The overall system balance equation of the target structural component is constructed by using the macroscopic system balance equation, the microscopic system balance equation and the interface system balance equation, and a multi-scale smooth finite element model of the target structural component is constructed according to the overall system balance equation;

[0222] According to a preset reconstruction post-processing strategy, a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model is performed in a microscopic region in the multi-scale smooth finite element model to obtain an updated multi-scale smooth finite element model;

[0223] A mechanical parameter data set is obtained, and the updated multi-scale smooth finite element model is used to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

[0224] Specifically, the specific implementation method of the processor 10 for the above instructions can refer to Figures 1 to 5 The description of the relevant steps in the corresponding embodiments will not be repeated here.

[0225] Furthermore, if the module / unit integrated in the electronic device 1 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer-readable storage medium can be volatile or non-volatile. For example, the computer-readable medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, and a read-only memory (ROM).

[0226] The present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor of an electronic device, the computer program can implement:

[0227] Using a pre-built multi-scale scanning device, a pre-built target structural component is scanned to obtain a scanning result of the structural component, and the scanning result of the structural component is subjected to macro-micro smooth modeling to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element;

[0228] Performing edge-based smooth domain construction operations on the two-dimensional smooth finite element plate and shell elements and the three-dimensional smooth finite element body elements to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix;

[0229] Obtaining an initialization material constant matrix, and constructing a macroscopic region stiffness matrix and a microscopic region stiffness matrix according to the initialization material constant matrix, a two-dimensional smooth domain matrix, and a three-dimensional smooth domain matrix;

[0230] Based on the pre-built smooth Galerkin W 2 In the form of, using the macroscopic region stiffness matrix and the microscopic region stiffness matrix, construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation, and couple the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation to obtain the interface region system equilibrium equation;

[0231] The overall system balance equation of the target structural component is constructed by using the macroscopic system balance equation, the microscopic system balance equation and the interface system balance equation, and a multi-scale smooth finite element model of the target structural component is constructed according to the overall system balance equation;

[0232] According to a preset reconstruction post-processing strategy, a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model is performed in a microscopic region in the multi-scale smooth finite element model to obtain an updated multi-scale smooth finite element model;

[0233] A mechanical parameter data set is obtained, and the updated multi-scale smooth finite element model is used to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

[0234] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, systems and methods can be implemented in other ways. For example, the system embodiments described above are only illustrative, and actual implementation may have other division methods.

[0235] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0236] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0237] It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0238] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A residual stress mechanical analysis method based on carbon fiber body structural parts, characterized in that: The method comprises: Using a pre-built multi-scale scanning device, a pre-built target structural component is scanned to obtain a scanning result of the structural component, and the scanning result of the structural component is subjected to macro-micro smooth modeling to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element; Performing edge-based smooth domain construction operations on the two-dimensional smooth finite element plate and shell elements and the three-dimensional smooth finite element body elements to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix; Obtaining an initialization material constant matrix, and constructing a macroscopic region stiffness matrix and a microscopic region stiffness matrix according to the initialization material constant matrix, a two-dimensional smooth domain matrix, and a three-dimensional smooth domain matrix; Based on the pre-built smooth Galerkin W 2 In the form of, using the macroscopic region stiffness matrix and the microscopic region stiffness matrix, construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation, and couple the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation to obtain the interface region system equilibrium equation; The overall system balance equation of the target structural component is constructed by using the macroscopic system balance equation, the microscopic system balance equation and the interface system balance equation, and a multi-scale smooth finite element model of the target structural component is constructed according to the overall system balance equation; According to a preset reconstruction post-processing strategy, a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model is performed in a microscopic region in the multi-scale smooth finite element model to obtain an updated multi-scale smooth finite element model; A mechanical parameter data set is obtained, and the updated multi-scale smooth finite element model is used to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

2. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 1 is characterized in that: The pre-constructed target structural part is scanned by using a pre-constructed multi-scale scanning device to obtain a scanning result of the structural part, and the scanning result of the structural part is subjected to smooth modeling based on macro-micro to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element, including: Using a pre-built multi-scale scanning device, respectively, to perform a scanning operation based on millimeter-level X-rays and micrometer-level X-rays on a pre-built target structural component, to obtain a millimeter-level light scanning result sequence and a micrometer-level light scanning result sequence, and using the millimeter-level light scanning result sequence and the micrometer-level light scanning result sequence as the structural component scanning result; Discretizing the problem domain based on the structural morphology of the millimeter light scanning result sequence and the micrometer light scanning result sequence to obtain a macroscopic region, a microscopic region and an intersection region; Using a pre-built smooth finite element modeling algorithm, two-dimensional shell modeling is performed on the millimeter light scanning results corresponding to the macroscopic area in the millimeter light scanning result sequence to obtain two-dimensional smooth finite element plate and shell elements, and three-dimensional solid modeling is performed on the micron light scanning results corresponding to the microscopic area in the micron light scanning result sequence to obtain three-dimensional smooth finite element body elements.

3. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 2 is characterized in that: The pre-constructed smooth Galerkin W 2 In the form of macroscopic region stiffness matrix and microscopic region stiffness matrix, the macroscopic region system equilibrium equation and microscopic region system equilibrium equation are constructed, including: Based on the pre-built smooth Galerkin W 2 In this form, the strain energy characteristics between each smooth domain in the smooth domain set are obtained, and the strain energy characteristic distribution is obtained; identifying the convergence of the strain energy characteristic distribution and obtaining a non-convergence region; When the non-convergence region exists in the strain energy characteristic distribution, the smooth domain set is stratified according to the non-convergence region to obtain a stratification result; According to the stratification results, the macroscopic region stiffness matrix and the microscopic region stiffness matrix are constructed in batches to construct the macroscopic region system equilibrium equation and the microscopic region system equilibrium equation.

4. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 3 is characterized in that: The system balance equation of the macroscopic region and the system balance equation of the microscopic region are coupled to obtain the system balance equation of the interface region, including: Constructing a combined multi-point constraint equation for the intersection area; The combined multi-point constraint equation, the macroscopic system equilibrium equation and the microscopic system equilibrium equation are coupled by using a pre-constructed full Lagrangian algorithm to obtain the interface system equilibrium equation.

5. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 4 is characterized in that: The method of performing a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model in a microscopic region of the multi-scale smooth finite element model according to a preset reconstruction post-processing strategy to obtain an updated multi-scale smooth finite element model includes: obtaining a stress prediction network from the multi-scale smooth finite element model; Obtain each smooth domain in the two-dimensional smooth finite element plate and shell element and the three-dimensional smooth finite element body element to obtain a smooth domain set; Obtaining an assumption in a preset reconstruction post-processing strategy, wherein the assumption is that the stress value of the smooth domain is the stress value of the center point of the smooth domain; Obtaining the smooth domain center point corresponding to each smooth domain in the smooth domain set, and calculating the stress value of each smooth domain center point using the stress prediction network according to the assumed conditions; Using the point interpolation method in the pre-built meshless algorithm, a node set is obtained, and the stress value of the center point of each smooth domain is converted into the stress value of each node in the node set, wherein one node is shared by multiple smooth domains; Obtaining the smooth domain area of ​​each node in the node set to obtain a smooth domain area set, and performing weighted average calculation on the stress value of each node in the node set based on the smooth domain area set to obtain a post-processing node stress value set; According to the post-processing node stress value set, the stress value of each smooth domain center point in the stress prediction network is updated to obtain an updated stress prediction network, and according to the updated stress prediction network, an updated multi-scale smooth finite element model is obtained.

6. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 5 is characterized in that: The step of obtaining a mechanical parameter data set comprises: Obtaining mechanical parameters of the carbon fiber composite material matrix and fibers of the target structural component to obtain basic mechanical parameters; Using a pre-built high-precision CT scanning device, the fiber volume rate distribution of different parts of the target structural component in the thickness direction is measured to obtain the fiber volume rate; The pre-constructed micromechanical model is used to predict the basic mechanical parameters and fiber volume fraction to obtain a mechanical parameter data set.

7. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 6 is characterized in that: After obtaining the residual stress distribution, the method further comprises: Predicting warpage deformation using the residual stress distribution to obtain a predicted warpage amount; Using a pre-built experimental measurement algorithm, the target structural component is measured to obtain an experimental measurement result; Calculating the difference between the predicted warpage amount and the experimental measurement result; Determine whether the difference is greater than a preset qualified threshold; When the difference is greater than the qualified threshold, model parameter training is performed on the updated multi-scale smooth finite element model to obtain an optimized updated multi-scale smooth finite element model.

8. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 7 is characterized in that: The method of constructing the total system balance equation of the target structural component by using the system balance equation of the macroscopic region, the system balance equation of the microscopic region and the system balance equation of the interface region includes: Obtaining the positional relationship between the macroscopic region, the microscopic region and the junction region; According to the positional relationship, parameter range constraints are imposed on the macroscopic region system balance equation, the microscopic region system balance equation and the boundary region system balance equation to obtain the total system balance equation.

9. The residual stress mechanical analysis method based on carbon fiber vehicle body structural parts according to claim 8, characterized in that: Prior to using the pre-built smooth finite element modeling algorithm, the method further includes: Determining the region type of the target structural component; When the region type is the macro region, the smooth finite element modeling algorithm is executed using a pre-constructed quadrilateral-triangle hybrid network; When the region type is the mesoscopic region, the smooth finite element modeling algorithm is executed using pre-constructed unstructured three-dimensional tetrahedral elements.

10. A residual stress mechanical analysis system based on carbon fiber body structural parts, characterized in that: The system comprises: A smooth domain construction module is used to scan a pre-constructed target structural part by using a pre-constructed multi-scale scanning device to obtain a scanning result of the structural part, and to perform macro-micro smooth modeling on the scanning result of the structural part to obtain a two-dimensional smooth finite element plate and shell element and a three-dimensional smooth finite element body element, and to perform an edge-based smooth domain construction operation on the two-dimensional smooth finite element plate and shell element and the three-dimensional smooth finite element body element to obtain a two-dimensional smooth domain matrix and a three-dimensional smooth domain matrix; The structural component model building module is used to obtain the initial material constant matrix, and to construct the macroscopic region stiffness matrix and the microscopic region stiffness matrix according to the initial material constant matrix, the two-dimensional smooth domain matrix and the three-dimensional smooth domain matrix, and to construct the smooth Galerkin W 2 The macroscopic region stiffness matrix and the microscopic region stiffness matrix are used to construct the macroscopic region system balance equation and the microscopic region system balance equation, and the macroscopic region system balance equation and the microscopic region system balance equation are coupled to obtain the interface region system balance equation; the total system balance equation of the target structural component is constructed by using the macroscopic region system balance equation, the microscopic region system balance equation and the interface region system balance equation, and a multi-scale smooth finite element model of the target structural component is constructed according to the total system balance equation; A stress reconstruction module, used to perform a stress result reconstruction operation based on a multi-scale anisotropic material smooth finite element model in a microscopic region of the multi-scale smooth finite element model according to a preset reconstruction post-processing strategy, to obtain an updated multi-scale smooth finite element model; The warpage prediction module is used to obtain a mechanical parameter data set, and use the updated multi-scale smooth finite element model to calculate the residual stress of the target structural part according to the mechanical parameter data set to obtain the residual stress distribution.

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