Structural member fatigue judgment method and device and simulation equipment

Abstract

The embodiment of the invention relates to a structural member fatigue judgment method and device and simulation equipment, and the method comprises the steps: obtaining the information of a structural member, building a finite element model according to the information of the structural member, carrying out the random vibration response analysis of the finite element model, and obtaining the inherent frequency and RMS data; acquiring vibration duration and material parameters of the structural member, and calculating to obtain a fatigue limit value according to the vibration duration, the material parameters and the inherent frequency; obtaining a first judgment result according to the fatigue limit value and the stress result of the RMS data on the structural member, and when the RMS data is greater than the fatigue limit value, performing accumulated damage analysis on the structural member to obtain a second judgment result; and according to the first evaluation result and / or the second evaluation result, determining a joint risk level of the structural member. According to the method, the risk degree of the structural member can be determined, the risk area can be determined, and a direction is provided for optimization and improvement of the risk area.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of energy storage, in particular to a structure fatigue determination method, device and simulation equipment. BACKGROUND

[0002] In recent years, with the continuous acceleration of the iteration speed of industrial products, simulation technology is increasingly widely used in the field of engineering manufacturing. Through the establishment of a digital model to simulate the mechanical behavior of the product under actual working conditions (such as stress distribution, structural failure, fatigue life and heat conduction), the product development efficiency is significantly improved and the research and development cycle is shortened. However, the reliability of the simulation results has always been a key bottleneck restricting the landing of the technology, especially in the field of random vibration analysis which has a decisive influence on the safety and fatigue life of the structure.

[0003] In the evaluation of structural random vibration fatigue, the industry generally uses the input power spectral density curve (PSD) as the random vibration excitation, and calculates the stress root mean square value (RMS) of the structural response to determine the fatigue failure. The current mainstream criterion has two typical defects:

[0004] (1) Over-conservatism of 3σ criterion: The traditional method compares 3 times the standard deviation (3σ) of the RMS stress with the material yield strength to determine the failure. Although this criterion can cover extremely small probability events, it leads to premature material failure due to insufficient consideration of the nonlinear relationship between structural dynamic response and material fatigue characteristics, resulting in a serious underestimate of the strength margin and unnecessary waste of material resources.

[0005] (2) Over-laxity of empirical criterion: Some enterprises use non-3σ self-defined empirical threshold (such as 2σ or 2.5σ), which can alleviate the conservatism problem, but lacks theoretical basis and universality, and is prone to miss actual failure risks due to improper threshold setting, which may cause product reliability problems.

[0006] The above contradictions highlight the core defects of existing evaluation methods: the RMS stress linear amplification model based on static stress threshold (such as yield strength) cannot accurately represent the transient peak effect of structural dynamic response under random vibration load and the fatigue damage accumulation mechanism. Especially for complex structures with nonlinear modal characteristics, the existing method cannot quantify the correlation between transient resonance response and material fatigue limit, resulting in a significant deviation between simulation results and physical tests. This misjudgment not only causes repeated design iterations in the development process, but also may cause product failure risks in the later stage, which seriously restricts the rapid and reliable development of high-end equipment. SUMMARY

[0007] In view of the above problems, the present application provides a structure fatigue determination method, device and simulation equipment to solve the problems of over-conservatism of the existing 3σ criterion and over-laxity of the empirical criterion.

[0008] According to one aspect of the present application, a structural fatigue determination method is provided, the method comprising:

[0009] acquiring structural information and establishing a finite element model according to the structural information, performing random vibration response analysis on the finite element model, and acquiring natural frequency and RMS data;

[0010] acquiring a first evaluation result of the stress result of the structure according to the fatigue limit value and the RMS data, and when the RMS data is greater than the fatigue limit value, performing cumulative damage analysis on the structure to acquire a second evaluation result;

[0011] determining the combined risk level of the structure according to the first evaluation result and / or the second evaluation result.

[0012] In some optional embodiments, the acquiring of the structural information and the establishment of the finite element model according to the structural information specifically comprises:

[0013] acquiring geometric data, material data and load conditions in the structural information;

[0014] setting the boundary conditions of the finite element model through basic constraint setting and random vibration excitation loading;

[0015] selecting different elements for meshing the finite element model according to different structure types;

[0016] setting the structure connection of the finite element model, and defining the contact relationship of the finite element model according to a preset contact pair configuration rule.

[0017] In some optional embodiments, the random vibration response analysis on the finite element model to acquire the natural frequency and the RMS data specifically comprises:

[0018] performing modal analysis according to the mass matrix and the stiffness matrix in the finite element model to obtain the natural frequency and the mode shape vector;

[0019] obtaining the power spectral density according to the measured road spectrum data of the finite element model or a preset power spectral density, and acquiring the RMS data through a random vibration response model.

[0020] In some optional embodiments, the modal analysis according to the mass matrix and the stiffness matrix in the finite element model to obtain the natural frequency and the mode shape vector specifically comprises:

[0021] acquiring the mass matrix, the stiffness matrix and the modal coordinates in the finite element model, and obtaining the mode shape vector according to a single degree of freedom equation;

[0022] According to the mode shape vector and the modal coordinate, an inherent frequency is calculated by a sinusoidal vibration equation.

[0023] In some optional embodiments, a power spectral density or a preset power spectral density is obtained according to measured road spectrum data of the finite element model, and RMS data is obtained by a random vibration response model, specifically including:

[0024] A power spectral density is obtained according to measured road spectrum data of the finite element model or a preset power spectral density;

[0025] A stress response power spectral density is obtained according to a product of the power spectral density and a square of the transfer function;

[0026] A mean square value is obtained by frequency domain integration on the stress response power spectral density, and RMS data is obtained by taking a square root of the mean square value.

[0027] In some optional embodiments, a vibration duration and material parameters of the structural member are obtained, and according to the vibration duration, the material parameters and the inherent frequency, a fatigue limit value is calculated, specifically including:

[0028] An S-N curve is fitted by a basquin criterion, and a fatigue limit value of the cycle number N is solved by the S-N curve. f

[0029] In some optional embodiments, a first evaluation result of a stress result of the structural member is obtained according to the fatigue limit value and the RMS data, specifically including:

[0030] When the RMS data is less than the fatigue limit value, the structural member has no fatigue risk;

[0031] When the RMS data is greater than or equal to the fatigue limit value and the RMS data is less than a yield limit, the structural member has a fatigue risk;

[0032] When the RMS data is greater than the yield limit, the structural member appears plastic deformation;

[0033] When the RMS data is greater than or equal to a tensile limit, the structural member is completely damaged.

[0034] In some optional embodiments, when the RMS data is greater than the fatigue limit value, a second evaluation result is obtained by cumulative damage analysis on the structural member, specifically including:

[0035] A stress amplitude of the structural member at a main frequency resonance is calculated by steady-state sweep analysis;

[0036] A cycle number is set by the vibration duration, the inherent frequency and the preset power spectral density.​

[0037] fitting the S-N curve by material parameters;

[0038] calculating the cumulative damage value of the structure according to the stress amplitude, the power spectral density curve and the S-N curve, and by the basquin criterion;

[0039] determining the damage area and the maximum damage value of the structure according to the cumulative damage value, and generating a second evaluation result.

[0040] According to another aspect of the present application, there is provided a structure fatigue evaluation device, which comprises:

[0041] a random vibration response analysis module, which acquires structure information and establishes a finite element model according to the structure information, performs random vibration response analysis on the finite element model, and acquires natural frequency and RMS data;

[0042] a fatigue limit calculation module, which acquires vibration duration and material parameters of the structure, and calculates a fatigue limit value according to the vibration duration, the material parameters and the natural frequency;

[0043] a stress evaluation module, which acquires a first evaluation result of the stress result of the structure according to the fatigue limit value and the RMS data;

[0044] a cumulative damage analysis module, which performs cumulative damage analysis on the structure to acquire a second evaluation result when the RMS data is greater than the fatigue limit value;

[0045] and a joint risk level evaluation module, which determines the joint risk level of the structure according to the first evaluation result and / or the second evaluation result.

[0046] According to still another aspect of the present application, there is provided a simulation device, which is characterized in that it comprises a processor, a memory, a communication interface and a communication bus, and the processor, the memory and the communication interface complete communication with each other through the communication bus;

[0047] The memory is used to store at least one executable instruction, and the executable instruction makes the processor execute the operations of the structure fatigue evaluation method as described above.

[0048] The application provides a structural fatigue determination method, device and simulation equipment, which has the beneficial effect that: the application obtains structural information, establishes a finite element model according to the structural information, performs random vibration response analysis on the finite element model, obtains inherent frequency and RMS data, obtains vibration duration and material parameters of the structure, calculates a fatigue limit value according to the vibration duration, material parameters and inherent frequency, obtains a first evaluation result of the stress result of the structure according to the fatigue limit value and the RMS data, and when the RMS data is greater than the fatigue limit value, performs cumulative damage analysis on the structure to obtain a second evaluation result, and determines the joint risk level of the structure according to the first evaluation result and / or the second evaluation result. The structural fatigue determination method based on random vibration response analysis is more in line with the actual use conditions of the material compared with the harshness of the 3σ criterion, and the application considers the actual conditions such as the inherent main frequency and vibration duration of the structure, determines the vibration cycle number at the main frequency, and thus calculates the fatigue limit of the structure under the actual conditions, so as to ensure that the simulation result evaluation is consistent with the actual result. It can be seen that the application can not only determine the risk degree of the structure, but also determine the risk area of the structure, and provides a direction for optimization and improvement of the risk area.

[0049] The above description is only a summary of the technical solutions of the application, in order to more clearly understand the technical means of the embodiments of the application, the application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the specific embodiments of the application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0050] The accompanying drawings are included to provide a further understanding of the application and are incorporated herein and constitute a part of the detailed description. In the drawings:

[0051] Figure 1 A flowchart of a structural fatigue determination method of embodiment 1 is shown.

[0052] Figure 2 A flowchart of establishing a finite element model of embodiment 1 is shown.

[0053] Figure 3 A flowchart of performing random vibration response analysis on the finite element model to obtain inherent frequency and RMS data of embodiment 1 is shown.

[0054] Figure 4 A structural diagram of a structural fatigue determination device of embodiment 2 is shown.

[0055] Figure 5A schematic diagram of the simulation device according to Embodiment 3 of the present invention is shown. Detailed Implementation

[0056] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0057] Example 1:

[0058] Figure 1 This paper illustrates an embodiment of a structural component fatigue assessment method according to the present invention, which addresses the problems of over-conservatism in existing 3σ criteria and over-leniency in empirical criteria. The method includes:

[0059] Step 110 involves acquiring structural component information and establishing a finite element model based on this information. Random vibration response analysis is then performed on the finite element model to obtain natural frequencies and RMS data. Specifically, this includes: acquiring geometric data, material data, and load conditions from the structural component information; setting boundary conditions for the finite element model through basic constraint settings and random vibration excitation loading; meshing the finite element model using different elements selected for different structural types; setting connections for structural components within the finite element model and defining contact relationships according to preset contact pair configuration rules. Random vibration response analysis is then performed on the finite element model to obtain natural frequencies and RMS data. This includes: performing modal analysis based on the mass matrix and stiffness matrix in the finite element model to obtain natural frequencies and mode shape vectors; obtaining the power spectral density or a preset power spectral density based on the measured road spectrum data of the finite element model; and obtaining RMS data through the random vibration response model.

[0060] Step 120 involves obtaining the vibration duration and material parameters of the structural component, and calculating the fatigue limit value based on the vibration duration, material parameters, and natural frequency. Specifically, this includes fitting an SN curve using the Basquin criterion and determining the number of cycles N from the SN curve. f The fatigue limit value at that time.

[0061] 130. Based on the fatigue limit value and RMS data, a first judgment result is obtained from the stress results of the structural component. When the RMS data is greater than the fatigue limit value, a cumulative damage analysis is performed on the structural component to obtain a second judgment result. In step 130, the stress results of the structural component are judged based on the fatigue limit value and RMS data, specifically including: when the RMS data is less than the fatigue limit value, the structural component has no fatigue risk; when the RMS data is greater than or equal to the fatigue limit value and less than the yield strength, the structural component has fatigue risk; when the RMS data is greater than the yield strength, the structural component exhibits plastic deformation; when the RMS data is greater than or equal to the tensile strength, the structural component is completely damaged. When the RMS data exceeds the fatigue limit, the cumulative damage analysis of the structural component to obtain the second evaluation result specifically includes: calculating the stress amplitude of the structural component at the main frequency resonance through steady-state frequency sweep analysis; setting the number of cycles by setting the vibration duration and natural frequency, and obtaining the power spectral density or a preset power spectral density based on the measured road spectrum data of the finite element model; fitting the SN curve by setting material parameters; calculating the cumulative damage value of the structural component based on the stress amplitude, power spectral density curve, and SN curve, and using the Basquin criterion; determining the damage area and maximum damage value of the structural component based on the cumulative damage value, and generating the second evaluation result.

[0062] 140. Based on the first and / or second assessment results, determine the combined risk level of the structural component. In step 140, the evaluation of the combined risk level requires a comprehensive analysis and evaluation combining the first and second assessment results. The comprehensive risk assessment is divided into three levels: Level 1: No risk, no need to redesign or change materials; Level 2: Low risk, parts need to be optimized, such as increasing thickness, strengthening local structures, and increasing rigidity design; Level 3: High risk, parts need to be completely redesigned or the part materials need to be changed. Specific judgment rules and standards can be found in Tables 7 and 8.

[0063] Through steps 110-140, this invention acquires structural component information and establishes a finite element model based on that information. Random vibration response analysis is then performed on the finite element model to obtain natural frequencies and RMS data. The vibration duration and material parameters of the structural component are acquired, and the fatigue limit value is calculated based on these parameters. A first evaluation result is obtained based on the stress results of the structural component using the fatigue limit value and RMS data. If the RMS data exceeds the fatigue limit value, a second evaluation result is obtained by performing cumulative damage analysis on the structural component. The combined risk level of the structural component is determined based on the first and / or second evaluation results. This invention's structural component fatigue judgment method based on random vibration response analysis is more consistent with the actual operating conditions of materials compared to the stringency of the 3σ criterion. Furthermore, this invention considers the actual conditions such as the natural dominant frequency and vibration duration of the structure, determining the number of vibration cycles at the dominant frequency to calculate the fatigue limit of the structural component under actual conditions, ensuring consistency between simulation results and actual results. As can be seen, this invention can not only determine the risk level of structural components, but also the areas where risks occur, providing direction for the optimization and improvement of risk areas.

[0064] In one embodiment of step 110, see Figure 2 Obtaining structural component information and establishing a finite element model based on that information specifically includes:

[0065] 210. Obtain geometric data, material data, and load conditions from the structural component information. In step 210, the geometric data includes the CAD model, key dimensions, and assembly relationships; the material data includes elastic parameters such as elastic modulus, Poisson's ratio, and density, plastic parameters such as yield strength and ultimate strength, and fatigue parameters such as SN curves; the load conditions include static load conditions such as gravity and preload, and dynamic load conditions such as PSD acceleration spectrum.

[0066] 220. Set the boundary conditions of the finite element model by setting basic constraints and random vibration excitation loading; in step 220, the basic constraint setting may include bolt fixing by coupling the RBE2 main node + hole edge node, sliding support by CYCLSYMM axisymmetric constraint, and structural fixing by ENCASTRE full constraint.

[0067] 230. Different elements are selected for mesh generation of the finite element model based on different structural types. In step 230, the element type selection criteria can be found in Table 1 below for mesh generation.

[0068] Structure type Recommendation unit Applicable scenario Thin-walled shell CQUAD4 (Reduced Integration Shell) Thickness direction ≥ 3 integration points Solid structure C3D10M (10-node Tetrahedron) Curvature adaptation in stress concentration area Transition area C3D8I (Non-matching mode) Avoid shear locking

[0069] Table 1

[0070] In addition, mesh requirements for key regions in the finite element model can be specified using Table 2:

[0071] Region type Mesh layer Element size Weld toe ≥ 3 layers ≤ 3 mm Bolt hole circumference Radial mesh Hole edge ≤ 3 mm Contact surface Equal node density Matching dual mesh

[0072] Table 2

[0073] 240. The connections of the structural components within the finite element model are set, and the contact relationships of the finite element model are defined according to preset contact pair configuration rules. In step 240, the connection types are modeled according to Table 3 to achieve accurate transmission of vibration loads.

[0074]

[0075]

[0076] Table 3

[0077] The contact relationships of the finite element model are defined according to the preset contact pair configuration rules, as shown in Table 4, to simulate nonlinear interactions. It also includes contact initialization checks, such as interference detection, clearance control, and slip verification, thereby generating the finite element model.

[0078] Contact type Algorithm selection Friction coefficient Stiffness factor Metal-metal Surface-to-Surface 0.10～0.15 5.0～10.0 Rubber-metal Penalty Contact 0.50～0.70 0.5～1.0 Small slip area Tie constraint - Rigid connection

[0079] Table 4

[0080] In one embodiment of step 110, see Figure 3 Random vibration response analysis was performed on the finite element model to obtain natural frequencies and RMS data, specifically including:

[0081] 310. Modal analysis is performed based on the mass matrix and stiffness matrix in the finite element model to obtain the natural frequencies and mode shape vectors. In step 310, modal analysis is performed based on the mass matrix and stiffness matrix in the finite element model to obtain the natural frequencies and mode shape vectors. Specifically, this includes: obtaining the mass matrix, stiffness matrix, and modal coordinates in the finite element model; obtaining the mode shape vectors based on the single-degree-of-freedom equations; and calculating the natural frequencies based on the mode shape vectors and modal coordinates using the sinusoidal vibration equations.

[0082] 320. Obtain the power spectral density or a preset power spectral density based on the measured road spectrum data of the finite element model. In step 330, the power spectral density is converted from the measured road spectrum data of the finite element model or directly preset by the simulation technical specifications. The power spectral density curve can be obtained by Fourier transforming the displacement-time and acceleration-time data collected from the measured road spectrum.

[0083] In one embodiment of step 310, modal analysis is performed based on the mass matrix and stiffness matrix in the finite element model to obtain the natural frequencies and mode shape vectors. Specifically, this includes: obtaining the mass matrix, stiffness matrix, and modal coordinates in the finite element model; obtaining the mode shape vectors based on the single-degree-of-freedom equations; and calculating the natural frequencies based on the mode shape vectors and modal coordinates using the sinusoidal vibration equations.

[0084] Specifically, modal analysis is mainly used to calculate the vibration frequency ω of a structure. i and vibration mode φ i These are the natural frequencies and mode shape vectors. Modal analysis does not require consideration of external forces acting on the structure. If the effect of structural damping is ignored, the structure will undergo free vibration, which, combined with the dynamic differential equations, yields: Where [M] is the mass matrix, [K] is the stiffness matrix, and {x} is the physical displacement matrix. The physical displacement x(t) is converted into modal coordinates q(t), i.e., x(t) = φq(t).

[0085] By utilizing modal orthogonality, the original equations of motion can be transformed into single-degree-of-freedom equations. Where m i ,k i Let represent modal mass and stiffness. Decoupling this equation yields the natural frequencies and corresponding mode shapes for each order.

[0086] Through x(t) = φsin(ω) i The natural frequency is obtained by calculating t+θ, where φ is the mode shape vector and ω is the frequency. i : Natural frequency, θ is the phase angle, x(t) is the physical displacement. By decoupling this equation, we can obtain the natural frequencies of each order and the corresponding mode shapes.

[0087] In one embodiment of step 320, the power spectral density or a preset power spectral density is obtained based on the measured road spectrum data of the finite element model, and RMS data is obtained through the random vibration response model. Specifically, this includes: obtaining the power spectral density or a preset power spectral density based on the measured road spectrum data of the finite element model; obtaining the stress response power spectral density based on the product of the power spectral density and the square of the transfer function; obtaining the mean square value by frequency domain integration of the stress response power spectral density, and then taking the square root of the mean square value to obtain the RMS data.

[0088] Specifically, the statistical characteristics of random excitation are characterized by the power spectral density (PSD). The PSD of the input excitation, such as the acceleration power spectral density (PSD), is multiplied by the square of the transfer function to obtain the stress response power spectral density, i.e., the stress response PSD. The formula is: PSD 应力 (f)=|H(f) 2 |·PSD 激励(f) The acceleration PSD can obtain the power spectral density or the preset power spectral density based on the measured road spectrum data of the finite element model.

[0089] The transfer function H(f) is determined by the decoupled modal mass, modal stiffness, modal damping, and natural frequency in modal analysis.

[0090] To solve for the root mean square (RMS) stress of a structure, it is necessary to first integrate the stress response PSD in the frequency domain to obtain the mean square value, and then take the square root to obtain the RMS data.

[0091] In step 120, the vibration duration and material parameters of the structural component are obtained. Based on the vibration duration, material parameters, and natural frequency, the fatigue limit value is calculated. Specifically, this includes fitting the SN curve using the Basquin criterion and solving for the number of cycles N using the SN curve. f The fatigue limit value at that time.

[0092] Specifically, this calculation method adopts the Basquin criterion and considers parameters including the structure's first natural principal frequency ω, vibration duration T, material yield strength, yield strength failure cycle number, fatigue strength, and fatigue strength failure cycle number σ. e ,N1,σ r N2. The first-order natural principal frequency ω and vibration duration T of the structure determine the number of cycles N that the structure can undergo under fatigue limit stress radiation. f In addition, considering the material's yield strength, yield strength failure cycle count, fatigue strength, and fatigue strength failure cycle count σ, e ,N1,σ r N2, using the Basquin criterion to fit the SN curve, solve for the number of iterations N. f The material stress amplitude at which the fatigue limit S is reached is called the fatigue limit. L S L The solution can be expressed in the following functional form:

[0093] S L =f(ω,T,σ) e ,N1,σ r N2)

[0094] The function f is a multi-parameter function based on the Basquin criterion.

[0095] The Basquin criterion primarily explains the relationship between stress amplitude and cycle number in a material, and is suitable for fitting high-cycle fatigue parameters. This criterion is typically derived from the material's fatigue strength and SN curves to obtain the constants in the Basquin equation. The basic equation of the Basquin criterion is as follows:

[0096] σa =σ′ f ·(2N) b

[0097] in,

[0098] σ a The stress amplitude is half of the stress range, Δσ / 2

[0099] σ′ f The fatigue strength coefficient is a material constant determined by parameters such as the material's yield strength and the number of cycles, such as σ. e ,N1,σ r N2, etc.; b is the fatigue strength index, determined by parameters such as the material's yield strength and number of cycles, such as σ. e ,N1,σ r ,N2, etc., where σ r =d·σ e d is the fatigue strength reduction factor. N is the fatigue failure cycle number, which is used when calculating the number of cycles at the dominant frequency determined by the material's structure. f =ω·T.

[0100] In step 130, a first evaluation result is obtained based on the stress result of the structural component according to the fatigue limit value and RMS data. Specifically, this includes: when the RMS data is less than the fatigue limit value, the structural component has no fatigue risk; when the RMS data is greater than or equal to the fatigue limit value and less than the yield strength, the structural component has fatigue risk; when the RMS data is greater than the yield strength, the structural component exhibits plastic deformation; and when the RMS data is greater than or equal to the tensile strength, the structural component is completely damaged.

[0101] Specifically, by comparing the maximum RMS data of each structural component obtained from random response simulation with the fatigue limit value of the corresponding material based on the Basquin criterion, the fatigue stress evaluation is shown in Table 5. L When σ is within the range, the structural components can be considered to have no fatigue risk; if σ e >RMS>S L If the RMS value exceeds σ, then there is a risk of fatigue, requiring additional cumulative damage analysis and evaluation based on the damage results. e If RMS ≥ UTS, the structural component is considered to have undergone plastic deformation, requiring a redesign or material replacement. If RMS ≥ UTS, the structural component is considered completely damaged, requiring a redesign and material replacement. The stress results can be used to assess the risk level in Table 5 below. In Table 5, RMS represents the RMS data, and S... L σ is the fatigue limit value. e UTS is the yield strength, and UTS is the tensile strength.

[0102] ​

[0103] Table 5

[0104] In step 130, when the RMS data exceeds the fatigue limit, cumulative damage analysis is required. This includes: calculating the stress amplitude of the structural component at the main frequency resonance through steady-state frequency sweep analysis; setting the number of cycles based on vibration duration and natural frequency, and obtaining the power spectral density or a preset power spectral density based on the measured road spectrum data of the finite element model; fitting the SN curve through material parameter settings; calculating the cumulative damage value of the structural component based on the stress amplitude, power spectral density curve, and SN curve, and using the Basquin criterion; and determining the damage area and maximum damage value of the structural component based on the cumulative damage value.

[0105] In this embodiment, the cumulative damage analysis requires a steady-state frequency sweep analysis first, followed by a cyclic cumulative damage analysis. The number of cycles needs to be set according to the vibration duration and the natural dominant frequency of the structure. The excitation of random vibration (power spectral density curve) is input, and the SN curve is fitted according to the material parameters and the cumulative damage value is solved by combining fatigue damage theory.

[0106] The main purpose of frequency sweep analysis is to calculate the stress amplitude of the structure and its components when the structure resonates at the dominant frequency. By combining the stress amplitude, random vibration excitation, SN curve, and fatigue damage theory, the cumulative damage value of the components can be calculated, and the fatigue risk of the components can be determined.

[0107] Cumulative damage analysis yields damage values ​​at different locations of a component under random vibration excitation, identifying damage areas and maximum damage values, and generating a second assessment result. The damage results are evaluated using Table 6 below, comparing damage values ​​with assessment limit ranges to determine the damage risk level of high-damage areas of the component. Damage areas are represented in the simulation cloud map of the structural component, and different colors indicate the degree of damage risk. In Table 6, D represents the damage value; the second assessment result can include the damage area, damage value, maximum damage value, and corresponding damage risk level.

[0108]

[0109] Table 6

[0110] The assessment of the combined risk level requires a comprehensive analysis and evaluation combining the results of the first and second assessments. The comprehensive risk assessment is divided into three levels, as shown in Table 7, and the evaluation criteria for each level are shown in Table 8. In Table 7, RMS represents RMS data, and S... L σ is the fatigue limit value. e UTS is the yield strength, UTS is the tensile strength, and D is the damage value in the second evaluation result.

[0111]

[0112] Table 7

[0113]

[0114] Table 8

[0115] Example 2:

[0116] Figure 4 This invention illustrates one embodiment of a structural component fatigue assessment device. The structural component fatigue assessment device is used to execute a structural component fatigue assessment method in Embodiment 1. The structural component fatigue assessment device 400 specifically includes a random vibration response analysis module 410, a fatigue limit calculation module 420, a stress assessment module 430, a cumulative damage analysis module 440, and a joint risk level assessment module 450.

[0117] The random vibration response analysis module 410 is used to execute step 110 in Embodiment 1, specifically including: acquiring structural component information and establishing a finite element model based on the structural component information, specifically including: acquiring geometric data, material data, and load conditions from the structural component information; setting boundary conditions for the finite element model through basic constraint settings and random vibration excitation loading; meshing the finite element model by selecting different elements for different structural types; setting the connection of structural components within the finite element model and defining the contact relationship of the finite element model according to preset contact pair configuration rules. Random vibration response analysis is performed on the finite element model to obtain natural frequencies and RMS data, specifically including: obtaining natural frequencies and mode shape vectors through modal analysis based on the mass matrix and stiffness matrix in the finite element model; obtaining the power spectral density based on the natural frequencies using the modal superposition method, and obtaining RMS data through the random vibration response model.

[0118] The fatigue limit calculation module 420 is used to execute step 120 in Embodiment 1, specifically including: obtaining the vibration duration and material parameters of the structural component; calculating the fatigue limit value based on the vibration duration, material parameters, and natural frequency; specifically including: fitting the SN curve using the Basquin criterion; and solving for the number of cycles N using the SN curve. f The fatigue limit value at that time.

[0119] The stress determination module 430 is used to execute step 130 in embodiment 1, specifically including: determining the stress result of the structural component based on the fatigue limit value and RMS data, specifically including: when the RMS data is less than the fatigue limit value, the structural component has no fatigue risk; when the RMS data is greater than or equal to the fatigue limit value and the RMS data is less than the yield limit, the structural component has fatigue risk; when the RMS data is greater than the yield limit, the structural component exhibits plastic deformation; when the RMS data is greater than or equal to the tensile limit, the structural component is completely damaged.

[0120] The cumulative damage analysis module is used to execute step 130 in Example 1, specifically including: when the RMS data is greater than the fatigue limit value, performing cumulative damage analysis on the structural component to obtain a second evaluation result specifically includes: calculating the stress amplitude of the structural component at the main frequency resonance through steady-state frequency sweep analysis; setting the number of cycles through vibration duration and natural frequency settings, and obtaining the power spectral density or a preset power spectral density based on the measured road spectrum data of the finite element model; fitting the SN curve through material parameter settings; calculating the cumulative damage value of the structural component based on the stress amplitude, power spectral density curve and SN curve, and using the Basquin criterion; determining the damage area and maximum damage value of the structural component based on the cumulative damage value, and generating a second evaluation result.

[0121] The joint risk level determination module 450 is used to execute step 140 in embodiment 1, specifically including: the evaluation of the joint risk level needs to be combined with the first evaluation result and the second evaluation result for comprehensive analysis and evaluation, and the comprehensive risk evaluation is divided into three levels.

[0122] Example 3:

[0123] Figure 5 The diagram shows a structural schematic of an embodiment of the simulation device of the present invention. The specific embodiments of the present invention do not limit the specific implementation of the simulation device.

[0124] like Figure 5 As shown, the simulation device may include: a processor 502, a communications interface 504, a memory 506, and a communications bus 508.

[0125] The processor 502, communication interface 504, and memory 506 communicate with each other via communication bus 508. Communication interface 504 is used to communicate with other network elements, such as clients or other servers. Processor 502 executes program 510, specifically performing the relevant steps in the fiber path compensation method embodiment described above.

[0126] Specifically, program 510 may include program code, which includes computer-executable instructions.

[0127] Processor 502 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The substructure-based container structure simulation equipment includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0128] Memory 506 is used to store program 510. Memory 506 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0129] Specifically, program 510 can be called by processor 502 to cause the simulation device to perform steps 110-130 of embodiment 1.

[0130] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Furthermore, the embodiments of this invention are not directed to any particular programming language.

[0131] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. Similarly, for the sake of brevity and to aid in understanding one or more aspects of the invention, in the description of exemplary embodiments of the invention above, various features of the embodiments are sometimes grouped together in a single embodiment, figure, or description thereof. The claims, which follow the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0132] Those skilled in the art will understand that the modules in the device of the embodiment can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiment can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components, except that at least some of such features and / or processes or units are mutually exclusive.

[0133] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A method for fatigue assessment of structural components, characterized in that, The method includes: Obtain structural component information and establish a finite element model based on the structural component information. Perform random vibration response analysis on the finite element model to obtain natural frequency and RMS data. The vibration duration and material parameters of the structural component are obtained, and the fatigue limit value is calculated based on the vibration duration, material parameters and natural frequency. A first evaluation result is obtained based on the stress results of the structural component according to the fatigue limit value and RMS data. When the RMS data is greater than the fatigue limit value, a cumulative damage analysis is performed on the structural component to obtain a second evaluation result. Based on the first and / or second assessment results, the joint risk level of the structural component is determined.

2. The method for determining fatigue of structural components according to claim 1, characterized in that, The process of acquiring structural component information and establishing a finite element model based on that information specifically includes: Obtain geometric data, material data, and load conditions from structural component information; The boundary conditions of the finite element model are set by setting basic constraints and applying random vibration excitation. Different elements are selected for mesh generation of the finite element model based on different structural types; The structural component connections of the finite element model are set, and the contact relationships of the finite element model are defined according to the preset contact pair configuration rules.

3. The fatigue assessment method for structural components according to claim 1, characterized in that, The finite element model is subjected to random vibration response analysis to obtain natural frequencies and RMS data, specifically including: Modal analysis is performed based on the mass matrix and stiffness matrix in the finite element model to obtain the natural frequencies and mode shape vectors; The power spectral density or a preset power spectral density is obtained from the measured road spectrum data of the finite element model, and the RMS data is obtained through the random vibration response model.

4. The fatigue assessment method for structural components according to claim 3, characterized in that, Modal analysis is performed based on the mass matrix and stiffness matrix in the finite element model to obtain the natural frequencies and mode shape vectors, specifically including: Obtain the mass matrix, stiffness matrix, and modal coordinates from the finite element model, and obtain the mode shape vector based on the single-degree-of-freedom equation; The natural frequency is obtained by calculating the sinusoidal vibration equation based on the mode shape vector and modal coordinates.

5. The fatigue assessment method for structural components according to claim 4, characterized in that, The power spectral density or a preset power spectral density is obtained based on the measured road spectrum data from the finite element model, and the RMS data is obtained through a random vibration response model, specifically including: The power spectral density or a preset power spectral density is obtained from the measured road spectrum data of the finite element model. The stress response power spectral density is obtained by multiplying the power spectral density by the square of the transfer function. The mean square value is obtained by integrating the power spectral density of the stress response in the frequency domain, and then the square root of the mean square value is taken to obtain the RMS data.

6. The fatigue assessment method for structural components according to claim 5, characterized in that, The process of obtaining the vibration duration and material parameters of the structural component, and calculating the fatigue limit value based on the vibration duration, material parameters, and natural frequency, specifically includes: The SN curve is fitted using the Basquin criterion, and the number of iterations N is calculated from the SN curve. f The fatigue limit value at that time.

7. The fatigue assessment method for structural components according to claim 6, characterized in that, The first evaluation result is obtained based on the stress results of the structural component according to the fatigue limit value and RMS data, specifically including: When the RMS data is less than the fatigue limit value, the structural component has no fatigue risk; When the RMS data is greater than or equal to the fatigue limit value and the RMS data is less than the yield limit, the structural component is at risk of fatigue. When the RMS data is greater than the yield strength, the structural component undergoes plastic deformation; When the RMS data is greater than or equal to the tensile limit, the structural component is completely damaged.

8. The fatigue assessment method for structural components according to claim 7, characterized in that, When the RMS data exceeds the fatigue limit value, a cumulative damage analysis is performed on the structural component to obtain a second evaluation result, specifically including: The stress amplitude of the structural component at the main frequency resonance is calculated by steady-state frequency sweep analysis. The number of cycles is set by adjusting the vibration duration and natural frequency, and the power spectral density or preset power spectral density is obtained based on the measured road spectrum data of the finite element model. Fit the SN curve by setting material parameters; Based on the stress amplitude, power spectral density curve and SN curve, the cumulative damage value of the structural component is calculated using the Basquin criterion. The damage area and maximum damage value of the structural component are determined based on the cumulative damage value, and a second evaluation result is generated.

9. A fatigue assessment device for structural components, characterized in that, The device includes: The random vibration response analysis module is used to acquire structural component information and establish a finite element model based on the structural component information, perform random vibration response analysis on the finite element model, and acquire natural frequency and RMS data. The fatigue limit calculation module is used to obtain the vibration duration and material parameters of the structural component, and calculate the fatigue limit value based on the vibration duration, material parameters and natural frequency. The stress determination module is used to obtain a first evaluation result based on the stress results of the structural component according to the fatigue limit value and RMS data. The cumulative damage analysis module is used to perform cumulative damage analysis on the structural component and obtain a second evaluation result when the RMS data is greater than the fatigue limit value. And a joint risk level determination module, used to determine the joint risk level of the structural component based on the first assessment result and / or the second assessment result.

10. A simulation device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction that causes the processor to perform the operation of the structural fatigue determination method as described in any one of claims 1-8.

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