A material performance degradation test method and device, electronic equipment and medium

Abstract

Embodiments of the present application disclose a material performance degradation test method and device, electronic equipment and a medium. The method comprises: generating a subroutine for numerical simulation of the Shokrieh criterion based on the Shokrieh criterion; constructing a three-dimensional progressive damage analysis model of a composite material connection structure by using a finite element software, and performing load simulation on the three-dimensional progressive damage analysis model; and performing stress tensor calculation and failure judgment on the three-dimensional progressive damage analysis model based on the subroutine according to the load applied to the three-dimensional progressive damage analysis model, and simulating and testing the performance degradation process of the three-dimensional progressive damage analysis model. The above scheme can consider the symmetry and the influence of each stress component on each failure mode based on the Shokrieh criterion, more accurately simulate the damage process of the composite material, and be more consistent with the actual material performance degradation process.

Description

Technical Field

[0001] This application relates to the field of material performance testing technology, and in particular to a method, apparatus, electronic device and medium for testing material performance degradation. Background Technology

[0002] Material performance degradation simulation testing involves simulating the gradual decline in the performance of materials over long-term use or under specific environments. It simulates the failure mechanisms and predicts the performance of materials under complex working conditions, such as performance changes caused by fatigue, corrosion, and high temperature. Combining experimental and numerical simulation techniques, it provides a scientific basis for engineering applications.

[0003] However, as the accuracy requirements for finite element simulation analysis gradually increase, the accuracy of finite element simulation analysis in current material performance degradation simulation tests is difficult to meet user requirements, and it is difficult to accurately simulate the damage state and performance degradation process of materials. Summary of the Invention

[0004] This application provides a material performance degradation testing method, apparatus, electronic device, and medium to accurately simulate the material performance degradation process and improve the accuracy of material performance testing simulation.

[0005] According to one aspect of this application, a method for testing material property degradation is provided, the method comprising:

[0006] Based on the Shokrieh criterion, a subroutine is generated for numerical simulation of the Shokrieh criterion.

[0007] A three-dimensional progressive damage analysis model of the composite material connection structure was constructed using finite element software, and load simulation was performed on the three-dimensional progressive damage analysis model.

[0008] Based on the subroutine, the stress tensor of the three-dimensional progressive damage analysis model is calculated and failure is determined according to the load applied to the model, and the performance degradation process of the model is simulated and tested.

[0009] According to one aspect of this application, a material property degradation testing device is provided, the device comprising:

[0010] The subroutine generation module is used to generate subroutines for numerical simulation of the Shokrieh criterion based on the Shokrieh criterion.

[0011] The model building module is used to construct a three-dimensional progressive damage analysis model of the composite material connection structure using finite element software, and to simulate the application of loads to the three-dimensional progressive damage analysis model.

[0012] The simulation test module is used to perform stress tensor calculation and failure judgment on the three-dimensional progressive damage analysis model based on the load applied to the model according to the subroutine, and to simulate and test the performance degradation process of the three-dimensional progressive damage analysis model.

[0013] According to another aspect of this application, an electronic device is provided, the electronic device comprising:

[0014] At least one processor; and

[0015] A memory that is communicatively connected to at least one processor; wherein,

[0016] The memory stores a computer program that can be executed by at least one processor, such that the at least one processor is able to perform the material property degradation test method of any embodiment of this application.

[0017] According to another aspect of this application, a computer-readable storage medium is provided, which stores computer instructions for causing a processor to execute and implement the material property degradation testing method of any embodiment of this application.

[0018] The technical solution of this application embodiment, based on the Shokrieh criterion, generates a subroutine for numerical simulation of the Shokrieh criterion; it uses finite element software to construct a three-dimensional progressive damage analysis model of the composite material connection structure, and simulates the application of loads to the three-dimensional progressive damage analysis model; based on the subroutine, it calculates the stress tensor and determines the failure of the three-dimensional progressive damage analysis model according to the loads applied to it, and simulates the performance degradation process of the three-dimensional progressive damage analysis model. The above solution, based on the Shokrieh criterion and considering symmetry and the influence of each stress component on each failure mode, more accurately simulates the damage process of composite materials and more closely reflects the actual material performance degradation process.

[0019] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A flowchart of a material property degradation testing method provided in this application embodiment;

[0022] Figure 2 A flowchart of a material property degradation testing method is provided in another embodiment of this application;

[0023] Figure 3 A flowchart of a material property degradation testing method provided in another embodiment of this application;

[0024] Figure 4 A schematic diagram of a performance degradation model provided in another embodiment of this application;

[0025] Figure 5 A flowchart illustrating a specific implementation of the operation process of the VUMAT subroutine provided in another embodiment of this application;

[0026] Figure 6 This is a schematic diagram of the structure of a material property degradation testing device provided in an embodiment of this application;

[0027] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0029] It should be noted that the terms "first," "second," "third," "fourth," "actual," "preset," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] Figure 1This is a flowchart illustrating a material performance degradation testing method provided in an embodiment of this application. This embodiment is applicable to situations involving simulation testing of material performance degradation. The method can be executed by a material performance degradation testing device, which can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method includes:

[0031] S110. Based on the Shokrieh criterion, generate a subroutine for numerical simulation of the Shokrieh criterion.

[0032] The Shokrieh criterion is the core criterion for progressive failure analysis of composite materials. Based on the improved Hashin criterion, it extends the multidimensional failure mode identification and stiffness degradation mechanism, and is mainly used to predict the damage initiation, propagation and final failure behavior of composite materials under complex loads. The Shokrieh criterion defines seven typical failure modes, and judges the failure status of the model based on the seven typical failure modes to simulate the performance degradation process of the material.

[0033] In this embodiment, a subroutine can be generated based on the Shokrieh criterion. When this subroutine runs, it can perform numerical simulations of the Shokrieh criterion, that is, calculate the specific formulas for each failure mode in the Shokrieh criterion. This subroutine can be a VUMAT subroutine written in FORTRAN. The VUMAT subroutine can run in simulation software to calculate and analyze relevant parameters of the model within the simulation software.

[0034] S120. A three-dimensional progressive damage analysis model of the composite material connection structure is constructed using finite element software, and load simulation is performed on the three-dimensional progressive damage analysis model.

[0035] Finite element analysis (FEM) software refers to software capable of performing finite element analysis. FEM is a numerical calculation method that simulates the behavior of physical fields by discretizing complex geometric models into finite elements. It is widely used in structural mechanics, heat conduction, fluid mechanics, and other fields. FEM software can include simulation software such as ABAQUS, ANSYS, and SolidWorks. Composite material connection structures refer to structural forms that combine composite material components with other materials (metals or composite materials) into a whole through specific technologies. Their core function is to transfer loads and ensure structural integrity. These structures are widely used in aerospace, automotive, and shipbuilding fields and are a key aspect of composite material engineering applications. Composite material connection structures include mechanical connections, adhesive connections, and hybrid connections. Mechanical connections are made using fasteners such as bolts and rivets; adhesive connections are methods that use adhesives to connect composite material components; and hybrid connections combine both mechanical and adhesive connections. Three-dimensional progressive damage analysis models are numerical analysis methods used to simulate the gradual accumulation of damage to materials or structures under load until failure. Its core lies in dynamically tracking the entire process of damage from initiation to propagation by using stress-strain relationships, failure criteria, and material property degradation rules in three-dimensional space.

[0036] In this embodiment, a three-dimensional progressive damage analysis model of the composite material connection structure can be constructed in finite element software. Specifically, the composite material connection structure can be modeled using SolidWorks, and the constructed three-dimensional model can be imported into Hypermesh. Hypermesh parametric modeling is then used to establish hexahedral mesh finite element models of each component of the composite material connection structure, which are then imported into ABAQUS. In ABAQUS, the material cross-sectional properties of each component are defined, material characteristics are assigned to the model, and the components are assembled. After establishing the three-dimensional progressive loss analysis model, loads are applied to the three-dimensional progressive damage analysis model to simulate its load-bearing capacity.

[0037] S130. Based on the subroutine, the stress tensor of the three-dimensional progressive damage analysis model is calculated and failure is determined according to the load applied to the three-dimensional progressive damage analysis model, and the performance degradation process of the three-dimensional progressive damage analysis model is simulated and tested.

[0038] For example, in this embodiment, a subroutine calculates the stress tensor and determines failure based on the load applied to the three-dimensional progressive damage analysis model. Specifically, based on the load applied to the three-dimensional progressive damage analysis model, the subroutine calculates the strain on the model. Based on the strain and the stiffness matrix, the stress tensor is calculated. The stress components of the stress tensor are then substituted into the subroutine for further calculation to determine the failure process of each finite element, thus simulating the performance degradation process of the three-dimensional progressive damage analysis model. During the simulation, the load applied to the model is a variable. The load is continuously updated in each call to the subroutine for stress tensor calculation and failure determination. Generally, the applied load gradually increases until the element experiences a large stress tensor due to the large applied load, thus meeting the failure determination conditions and causing failure.

[0039] The technical solution of this application embodiment, based on the Shokrieh criterion, generates a subroutine for numerical simulation of the Shokrieh criterion; it uses finite element software to construct a three-dimensional progressive damage analysis model of the composite material connection structure, and simulates the application of loads to the three-dimensional progressive damage analysis model; based on the subroutine, it calculates the stress tensor and determines the failure of the three-dimensional progressive damage analysis model according to the loads applied to it, and simulates the performance degradation process of the three-dimensional progressive damage analysis model. The above solution, based on the Shokrieh criterion and considering symmetry and the influence of each stress component on each failure mode, more accurately simulates the damage process of composite materials and more closely reflects the actual material performance degradation process.

[0040] Figure 2 This is a flowchart illustrating a material property degradation testing method according to another embodiment of this application. This embodiment is an optimization based on the above embodiment; schemes not described in detail in this embodiment are described in the above embodiment. Figure 2 As shown, the method in this embodiment of the application specifically includes the following steps:

[0041] S210. Based on the relationship between the stiffness matrix, strain matrix, and stress matrix, generate a stress tensor calculation program for the three-dimensional progressive damage analysis model.

[0042] The stiffness matrix, in structural mechanics, is a mathematical expression describing the ability of a material or structure to resist deformation under stress. Essentially, it quantifies the rigidity characteristics of a structure through the linear relationship between nodal displacements and internal forces. In finite element analysis, the stiffness matrix is ​​combined with the stiffness matrices of individual elements to form an overall structural stiffness model, used to solve for mechanical responses such as displacement and stress. The strain matrix is ​​a mathematical tool describing the internal deformation state of a material, used to quantify the relative displacement distribution at various points after stress. In finite element analysis, the strain matrix converts the displacement field into a strain field through geometric relationships, serving as a core bridge connecting deformation geometry and material constitutive relations (such as stress-strain relationships). The stress matrix is ​​a mathematical tool describing the internal stress state of a material, used to quantify the internal force distribution at various points after stress. In continuum mechanics and finite element analysis, the stress matrix converts the strain field into a stress field through constitutive relations, serving as a core quantity connecting material deformation and mechanical response.

[0043] Assume the stress matrix is The strain matrix is The stiffness matrix is For a carbon fiber unidirectional plate, the carbon fibers are unidirectionally oriented in direction 1. The unidirectional plate has two orthogonal elastic symmetry planes, and because it can be fabricated as a typical orthotropic material for analysis, its stiffness matrix has only 9 independent variables, expressed as follows: The relationship between the stress matrix, strain matrix, and stiffness matrix is ​​as follows: Based on the relationship between the stress matrix, strain matrix, and stiffness matrix, a stress tensor calculation program is generated for the three-dimensional progressive damage analysis model. This program is used to calculate the stress tensor of the three-dimensional progressive damage analysis model and then analyze the tensile load-bearing capacity of the model.

[0044] S220. Based on the Shokrieh criterion, generate failure judgment procedures for fiber stretching mode, fiber compression mode, fiber-matrix shear mode, matrix stretching mode, matrix compression mode, normal stretching delamination mode, and normal compression delamination mode.

[0045] The Shokrieh criterion includes seven typical failure mode assessment models, thus taking into account symmetry and the influence of each stress component on each failure mode, and more accurately analyzing the failure situation of the three-dimensional progressive damage analysis model.

[0046] The fiber stretching mode is as follows:

[0047] Fiber compression mode:

[0048] Fiber-matrix shear mode:

[0049] Matrix stretching mode:

[0050] Matrix compression mode:

[0051] Normal stretching layering mode:

[0052] Normal compression layering mode:

[0053] Where, σ 11 σ 22 σ 33 These represent the normal stress components in the fiber, matrix, and thickness directions of the unidirectional plate, respectively; σ 12 σ 13 σ 23 These are the shear stress components in three planes; X T X C These represent the tensile and compressive strengths of the unidirectional fiber plate, respectively; Y T Y C These represent the tensile and compressive strengths of the unidirectional plate matrix, respectively; Z T Z C These represent the tensile and compressive strengths in the thickness direction of the unidirectional sheet, respectively; S 12 S 13 S 23 These represent the shear strength in the three planes of the one-way plate.

[0054] S230. A three-dimensional progressive damage analysis model of the composite material connection structure is constructed using finite element software, and load simulation is performed on the three-dimensional progressive damage analysis model.

[0055] S240. Based on the subroutine, the stress tensor of the three-dimensional progressive damage analysis model is calculated and failure is determined according to the load applied to the three-dimensional progressive damage analysis model, and the performance degradation process of the three-dimensional progressive damage analysis model is simulated and tested.

[0056] The technical solution of this application, based on the relationship between the stiffness matrix, strain matrix, and stress matrix, generates a stress tensor calculation program for the three-dimensional progressive damage analysis model. According to the Shokrieh criterion, it generates failure judgment programs for fiber tension mode, fiber compression mode, fiber-matrix shear mode, matrix tension mode, matrix compression mode, normal tension delamination mode, and normal compression delamination mode. Through the generation of these programs, the principled failure criteria are made executable and applied to the stress tensor calculation and failure judgment of the three-dimensional progressive damage analysis model, improving the accuracy of material property simulation testing.

[0057] Figure 3This is a flowchart illustrating a material property degradation testing method according to another embodiment of this application. This embodiment is an optimization based on the above embodiments; schemes not described in detail in this embodiment are found in the above embodiments. Figure 3 As shown, the method in this embodiment of the application specifically includes the following steps:

[0058] S310. Based on the Shokrieh criterion, generate a subroutine for numerical simulation of the Shokrieh criterion.

[0059] S320. A three-dimensional progressive damage analysis model of the composite material connection structure is constructed using finite element software, and load simulation is performed on the three-dimensional progressive damage analysis model.

[0060] S330. Calculate the stiffness matrix according to the constitutive model of orthogonal anisotropic materials.

[0061] Orthotropic materials have three mutually perpendicular planes of symmetry, each with a different elastic modulus, Poisson's ratio, and shear modulus. The three orthotropic directions are the fiber direction, the thickness direction, and the third perpendicular direction. When calculating the stiffness matrix, these material constants need to be organized into a 6x6 matrix. However, because there are nine independent parameters, the symmetry and anisotropy of the matrix must be considered. The following nine parameters are required for orthotropic materials: elastic modulus E1, E2, E3 (along the principal directions); Poisson's ratio: ν12, ν13, ν23; shear modulus: G12, G13, G23.

[0062] The flexibility matrix S is the inverse of the stiffness matrix, S = C -1 , By finding the inverse C = S -1 The stiffness matrix can be obtained.

[0063] S340. Calculate the strain of the current increment step based on the strain of the previous increment step and the strain increment of the current increment step.

[0064] The strain at the current increment step = the strain at the previous increment step + the strain increment at the current increment step.

[0065] S350. Update the stiffness matrix and determine the stress tensor based on the updated stiffness matrix and the current incremental strain step.

[0066] As the applied load changes, the strain in the three-dimensional progressive damage analysis model changes. As the strain changes, the elastic modulus, shear modulus, and Poisson's ratio used to calculate the stiffness matrix also change. The stiffness matrix is ​​then updated based on the changed elastic modulus, shear modulus, and Poisson's ratio. Finally, the stress tensor is determined based on the updated stiffness matrix and the strain at the current incremental step.

[0067] For example, updating the stiffness matrix includes:

[0068] The degradation ratio of each failure mode in the Shokrieh criterion is determined based on the sudden degradation model and the current incremental step strain.

[0069] Based on the degradation ratio of each failure mode, determine the corresponding elastic modulus, shear modulus and Poisson's ratio for each failure mode;

[0070] The stiffness matrix is ​​updated based on the elastic modulus, the shear modulus, and the Poisson's ratio.

[0071] When a composite material structure experiences localized damage during loading, it generally does not directly fail to bear the load. Gradual failure analysis uses materials with degraded properties to represent the material in the failure region, thereby reducing the stress in the failure area. A model defining the degradation of material properties after failure is called a material property degradation model.

[0072] Once a material reaches its failure criterion, it enters the damage evolution stage, which is the stage of strain energy dissipation. During this process, material softening macroscopically manifests as a decrease in load-bearing capacity due to stiffness (elastic modulus) degradation, until the material reaches its fracture energy release rate, at which point the material completely fails. Material failure is the process from micro-damage generating microcracks, which then propagate into macro-cracks. Figure 4 A schematic diagram illustrating the relationship between the degradation coefficient and strain in both the abrupt degradation model and the continuous degradation model is presented. Path OABC represents abrupt degradation, where the degradation coefficient suddenly drops to k when the strain reaches ε1, resulting in a sudden change or reduction in material properties. Unlike the abrupt degradation model, in the continuous degradation model, the material stiffness changes gradually. Path OAC represents continuous degradation; after the strain reaches ε1, the degradation coefficient does not immediately decrease to a value no greater than 1, but rather gradually decreases with increasing strain, exhibiting a linear or nonlinear relationship with strain. Material property degradation is a gradual process.

[0073] Unidirectional carbon fiber plates are linearly elastic brittle materials, and their stress drops sharply when they reach maximum strength. Therefore, the seven failure modes of the material in this application all adopt the sudden drop degradation model, and the stiffness attenuation criterion proposed by Tan et al. is used, as shown in Table 1. In the table, f... ft f fc f mt f mc f dt f dc f sh This represents the degradation percentage for each failure mode, with a value ranging from 0 to 1.

[0074] Table 1

[0075]

[0076] Based on the degradation ratio in Table 1, calculate the elastic modulus, shear modulus, and Poisson's ratio, and substitute them into the above formula for calculating the stiffness matrix to calculate the stiffness matrix.

[0077] S360. Substitute the stress tensor into the Shokrieh criterion of the subroutine to determine whether any failure mode in the Shokrieh criterion is satisfied. If satisfied, proceed to S370; otherwise, proceed to S390.

[0078] The subroutine is called to calculate the stress tensor and determine whether any of the failure modes in the Shokrieh criterion are satisfied, that is, whether at least one of the conditions of the seven failure modes is satisfied.

[0079] S370. Based on the damage variables of the current increment step, reduce the stiffness matrix and update the stress tensor according to the reduced stiffness matrix. Then, substitute the result back into the Shokrieh criterion of the subroutine to determine whether the complete failure condition is met. If it is met, proceed to S380; otherwise, proceed to S390.

[0080] Stiffness matrix reduction is a numerical simulation method that quantifies the degree of material damage by introducing damage variables and dynamically adjusting the material stiffness matrix to reflect the degradation of its mechanical properties. If a subroutine is called to calculate the stress tensor and determines that any failure mode in the Shokrieh criterion is satisfied, the stiffness matrix is ​​reduced based on the damage variables of the current increment step. The stress tensor is updated based on the reduced stiffness matrix and then substituted back into the Shokrieh criterion of the subroutine to determine whether the complete failure condition is met.

[0081] S380. Delete the unit from the three-dimensional progressive damage analysis model.

[0082] The complete failure conditions include the element simultaneously satisfying both fiber-direction tensile failure and matrix-direction tensile failure, the element satisfying fiber-matrix shear failure, and the element reaching a set maximum damage value when the damage from fiber tensile failure or fiber compression failure reaches a set maximum damage value. When any of the above complete failure conditions are met, the element is determined to be completely failed and can be deleted from the three-dimensional progressive damage analysis model, reflecting that the element no longer functions in the three-dimensional progressive damage analysis model.

[0083] S390. Otherwise, continue to perform stress tensor calculation and failure judgment on the three-dimensional progressive damage analysis model based on the load applied to the model according to the subroutine.

[0084] For example, if the three-dimensional progressive damage analysis model does not meet the complete failure condition, loads are continued to be applied to the three-dimensional progressive damage analysis model. Based on the subroutine, stress tensor calculation and failure judgment are performed on the three-dimensional progressive damage analysis model to determine the low stress magnitude that causes the element to completely fail, and the entire process of material performance degradation is simulated and tested.

[0085] The technical solution of this application embodiment calculates the stiffness matrix according to the constitutive model of orthotropic materials; calculates the strain of the current increment step based on the strain of the previous increment step and the strain increment of the current increment step; updates the stiffness matrix, and determines the stress tensor based on the updated stiffness matrix and the strain of the current increment step, thereby accurately calculating the stress tensor of the three-dimensional progressive damage analysis model. The stress tensor is then substituted into the Shokrieh criterion of the subroutine to determine whether any failure mode in the Shokrieh criterion is satisfied; if satisfied, the stiffness matrix is ​​reduced according to the damage variables of the current increment step, and the stress tensor is updated according to the reduced stiffness matrix. This is then substituted into the Shokrieh criterion of the subroutine again to determine whether the complete failure condition is satisfied, thereby judging whether the element fails due to the increase of stress, and thus realizing the simulation test of the material performance degradation process.

[0086] A flowchart illustrating a specific implementation of the VUMAT subroutine's operation process is shown below. Figure 5 As shown. Taking the algorithm flow of the subroutine in the (n+1)th increment step as an example, the specific calculation steps are as follows:

[0087] S401 reads parameters: The first category includes basic mechanical property parameters of the material, which are constants during the calculation and do not change with the increment step, as shown in Table 2; the second category is the variables passed from the main program to the subroutine, including the stress tensor of the nth increment step and the strain increment of the current (n+1)th increment step; the third category is the state variables calculated in the previous increment step and passed to the current increment step, including the damage variable of the nth increment step.

[0088] S402 calculates the stiffness matrix of the material according to the constitutive model of orthogonal anisotropic materials;

[0089] S403 calculates the strain of the current increment step: current increment step strain = strain of the previous increment step + strain increment of the current increment step;

[0090] S404 calculates and updates the material stiffness matrix;

[0091] S405 calculates the stress tensor of the current increment step based on the stiffness matrix;

[0092] S406 Material Failure Determination: Substitute the stress components into the failure criterion. If the criterion value of any failure mode is greater than 1, proceed to step S409; otherwise, proceed directly to step S407.

[0093] S407 stores and updates damage variables.

[0094] S408 incremental step ends, return to main program.

[0095] S409 calculates the damage variables for the current incremental step and reduces the stiffness matrix based on the obtained damage variables.

[0096] S410 determines whether the material is completely ineffective and whether the element deletion condition is met. If it is met, proceed to S411; otherwise, return to S407.

[0097] If the set cell deletion criterion is met, the cell deletion calculation ends.

[0098] When using Abaqus / Explicit to solve quasi-static problems, the solution geometry is the same as the true static solution when calculated in natural time, but this significantly increases computational cost. Therefore, methods such as using a smaller total computation time or mass scaling are generally employed to shorten the computation time. In fact, if the computation time is too short or the mass scaling factor is too large, the inertial force becomes extremely large, affecting the accuracy of the results. Therefore, this subroutine adds two parameters, parameters 27 and 28 in Table 2, which are the stiffness correction factor and strength correction factor (default value 1), respectively, to counteract the influence of excessively short computation time or excessively large mass scaling factors on material properties.

[0099] Table 2

[0100]

[0101]

[0102] Figure 6 This is a schematic diagram of a material property degradation testing device provided in an embodiment of this application. This device can execute the material property degradation testing method provided in any embodiment of this application, and possesses the corresponding functional modules and beneficial effects for executing the method. Figure 6 As shown, the device includes:

[0103] The subroutine generation module 410 is used to generate a subroutine for numerical simulation of the Shokrieh criterion based on the Shokrieh criterion.

[0104] The model building module 420 is used to build a three-dimensional progressive damage analysis model of the composite material connection structure using finite element software, and to simulate the application of loads to the three-dimensional progressive damage analysis model.

[0105] The simulation test module 430 is used to perform stress tensor calculation and failure judgment on the three-dimensional progressive damage analysis model based on the load applied to the three-dimensional progressive damage analysis model according to the subroutine, and to simulate and test the performance degradation process of the three-dimensional progressive damage analysis model.

[0106] In this embodiment of the application, the subroutine generation module 410 generates a subroutine for numerical simulation of the Shokrieh criterion based on the Shokrieh criterion, including:

[0107] Based on the relationship between the stiffness matrix, strain matrix, and stress matrix, a stress tensor calculation program is generated for the three-dimensional progressive damage analysis model.

[0108] Based on the Shokrieh criterion, a failure judgment procedure is generated for fiber stretching mode, fiber compression mode, fiber-matrix shear mode, matrix stretching mode, matrix compression mode, normal stretching delamination mode, and normal compression delamination mode.

[0109] In the embodiments of this application,

[0110] The fiber stretching mode is as follows:

[0111] Fiber compression mode:

[0112] Fiber-matrix shear mode:

[0113] Matrix stretching mode:

[0114] Matrix compression mode:

[0115] Normal stretching layering mode:

[0116] Normal compression layering mode:

[0117] Where, σ 11 σ 22 σ 33 These represent the normal stress components in the fiber, matrix, and thickness directions of the unidirectional plate, respectively; σ 12 σ 13 σ 23 These are the shear stress components in three planes; X T XC These represent the tensile and compressive strengths of the unidirectional fiber plate, respectively; Y T Y C These represent the tensile and compressive strengths of the unidirectional plate matrix, respectively; Z T Z C These represent the tensile and compressive strengths in the thickness direction of the unidirectional sheet, respectively; S 12 S 13 S 23 These represent the shear strength in the three planes of the one-way plate.

[0118] In this embodiment of the application, the simulation test module 430 calculates the stress tensor of the three-dimensional progressive damage analysis model based on the load applied to the model according to the subroutine, including:

[0119] The stiffness matrix is ​​calculated according to the constitutive model of orthogonal anisotropic materials;

[0120] Calculate the strain of the current increment step based on the strain of the previous increment step and the strain increment of the current increment step;

[0121] The stiffness matrix is ​​updated, and the stress tensor is determined based on the updated stiffness matrix and the current incremental strain step.

[0122] In this embodiment of the application, the simulation test module 430 updates the stiffness matrix, including:

[0123] The degradation ratio of each failure mode in the Shokrieh criterion is determined based on the sudden degradation model and the current incremental step strain.

[0124] Based on the degradation ratio of each failure mode, determine the corresponding elastic modulus, shear modulus and Poisson's ratio for each failure mode;

[0125] The stiffness matrix is ​​updated based on the elastic modulus, the shear modulus, and the Poisson's ratio.

[0126] In this embodiment of the application, the simulation test module 430, based on the subroutine, performs a failure judgment on the three-dimensional progressive damage analysis model according to the load applied to the model, including:

[0127] The stress tensor is substituted into the Shokrieh criterion of the subroutine to determine whether any failure mode in the Shokrieh criterion is satisfied.

[0128] If satisfied, the stiffness matrix is ​​reduced based on the damage variables of the current increment step, and the stress tensor is updated based on the reduced stiffness matrix. The stress tensor is then substituted back into the Shokrieh criterion of the subroutine to determine whether the complete failure condition is satisfied.

[0129] In this embodiment of the application, the device further includes:

[0130] The deletion module is used to delete the element from the three-dimensional progressive damage analysis model if the element in the model satisfies the complete failure condition.

[0131] The execution module continues, otherwise, based on the subroutine, to perform stress tensor calculation and failure determination on the three-dimensional progressive damage analysis model according to the load applied to the model.

[0132] The material performance degradation testing device provided in this application embodiment can execute a material performance degradation testing method provided in any embodiment of this application, and has the corresponding functional modules and beneficial effects of executing the method.

[0133] Figure 7 A schematic diagram of an electronic device 10, which can be used to implement embodiments of this application, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (such as helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the application described and / or claimed herein.

[0134] like Figure 7 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 may also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0135] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0136] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as material property degradation testing methods.

[0137] This application also provides a vehicle that may integrate electronic equipment 10, which is capable of performing the door and window control method described in any of the above embodiments.

[0138] In some embodiments, the material property degradation testing method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the material property degradation testing method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured to perform the material property degradation testing method by any other suitable means (e.g., by means of firmware).

[0139] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0140] Computer programs used to implement the methods of this application may be written in any combination of one or more programming languages. These computer programs may be provided to the processor of a general-purpose computer, a special-purpose computer, or other programmable material performance degradation testing apparatus, such that when executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0141] In the context of this application, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium can be, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0142] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0143] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or computing systems that include middleware components (e.g., application servers), or computing systems that include frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0144] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0145] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired information of the technical solution of this application can be achieved, and this is not limited herein.

[0146] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for testing material property degradation, characterized in that, The method includes: Based on the Shokrieh criterion, a subroutine is generated for numerical simulation of the Shokrieh criterion. A three-dimensional progressive damage analysis model of the composite material connection structure was constructed using finite element software, and load simulation was performed on the three-dimensional progressive damage analysis model. Based on the subroutine, the stress tensor of the three-dimensional progressive damage analysis model is calculated and failure is determined according to the load applied to the three-dimensional progressive damage analysis model, and the performance degradation process of the three-dimensional progressive damage analysis model is simulated and tested. Based on the Shokrieh criterion, a subroutine is generated for numerical simulation of the Shokrieh criterion, including: Based on the relationship between the stiffness matrix, strain matrix, and stress matrix, a stress tensor calculation program is generated for the three-dimensional progressive damage analysis model. Based on the Shokrieh criterion, a failure judgment procedure is generated for fiber stretching mode, fiber compression mode, fiber-matrix shear mode, matrix stretching mode, matrix compression mode, normal stretching delamination mode, and normal compression delamination mode. Based on the subroutine, the failure determination of the three-dimensional progressive damage analysis model is performed according to the load applied to the model, including: The stress tensor is substituted into the Shokrieh criterion of the subroutine to determine whether any failure mode in the Shokrieh criterion is satisfied. If satisfied, the stiffness matrix is ​​reduced based on the damage variables of the current increment step, and the stress tensor is updated based on the reduced stiffness matrix. The result is then substituted back into the Shokrieh criterion of the subroutine to determine whether the complete failure condition is satisfied.

2. The method according to claim 1, characterized in that, The fiber stretching mode is as follows: ; Fiber compression mode: ; Fiber-matrix shear mode: ; Matrix stretching mode: ; Matrix compression mode: ; Normal stretching layering mode: ; Normal compression layering mode: ; in, , , These are the normal stress components in the fiber, matrix, and thickness directions of the unidirectional plate, respectively. , , These are the shear stress components in the three planes, respectively. , These represent the tensile and compressive strengths of the unidirectional fiber plate, respectively. , These represent the tensile and compressive strengths in the matrix direction of the one-way plate, respectively. , These represent the tensile and compressive strengths in the thickness direction of the unidirectional plate, respectively. , , These represent the shear strength in the three planes of the one-way plate.

3. The method according to claim 1, characterized in that, Based on the subroutine, the stress tensor calculation of the three-dimensional progressive damage analysis model is performed according to the load applied to the model, including: The stiffness matrix is ​​calculated according to the constitutive model of orthogonal anisotropic materials; Calculate the strain of the current increment step based on the strain of the previous increment step and the strain increment of the current increment step; The stiffness matrix is ​​updated, and the stress tensor is determined based on the updated stiffness matrix and the current incremental strain step.

4. The method according to claim 3, characterized in that, The stiffness matrix is ​​updated, including: The degradation ratio of each failure mode in the Shokrieh criterion is determined based on the sudden degradation model and the current incremental step strain. Based on the degradation ratio of each failure mode, determine the corresponding elastic modulus, shear modulus and Poisson's ratio for each failure mode; The stiffness matrix is ​​updated based on the elastic modulus, the shear modulus, and the Poisson's ratio.

5. The method according to any one of claims 1-4, characterized in that, After performing stress tensor calculation and failure determination on the three-dimensional progressive damage analysis model, the method further includes: If a unit in the three-dimensional progressive damage analysis model satisfies the complete failure condition, then the unit is deleted from the three-dimensional progressive damage analysis model. Otherwise, the subroutine continues to perform stress tensor calculations and failure determination on the three-dimensional progressive damage analysis model based on the loads applied to it.

6. A material property degradation testing device, characterized in that, The device includes: The subroutine generation module is used to generate subroutines for numerical simulation of the Shokrieh criterion based on the Shokrieh criterion. The model building module is used to construct a three-dimensional progressive damage analysis model of the composite material connection structure using finite element software, and to simulate the application of loads to the three-dimensional progressive damage analysis model. The simulation test module is used to perform stress tensor calculation and failure judgment on the three-dimensional progressive damage analysis model based on the load applied to the three-dimensional progressive damage analysis model according to the subroutine, and to simulate and test the performance degradation process of the three-dimensional progressive damage analysis model. The subroutine generation module generates subroutines for numerical simulation of the Shokrieh criterion based on the Shokrieh criterion, including: Based on the relationship between the stiffness matrix, strain matrix, and stress matrix, a stress tensor calculation program is generated for the three-dimensional progressive damage analysis model. Based on the Shokrieh criterion, a failure judgment procedure is generated for fiber stretching mode, fiber compression mode, fiber-matrix shear mode, matrix stretching mode, matrix compression mode, normal stretching delamination mode, and normal compression delamination mode. The simulation testing module, based on the subroutine, performs failure assessment on the three-dimensional progressive damage analysis model according to the load applied to it, including: The stress tensor is substituted into the Shokrieh criterion of the subroutine to determine whether any failure mode in the Shokrieh criterion is satisfied. If satisfied, the stiffness matrix is ​​reduced based on the damage variables of the current increment step, and the stress tensor is updated based on the reduced stiffness matrix. The result is then substituted back into the Shokrieh criterion of the subroutine to determine whether the complete failure condition is satisfied.

7. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the material property degradation test method according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the material property degradation testing method according to any one of claims 1-5.

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