Crack propagation determination method and device, equipment and storage medium

Abstract

The invention discloses a crack propagation determination method and device, equipment and a storage medium. The invention relates to a crack propagation determination method, which comprises the following steps of: constructing a fatigue crack propagation model under high / low cycle fatigue load superposition response enhancement according to a resonance theory and a fatigue crack propagation rate model in vibration dynamics; building a crack propagation analysis model of the target structure according to the finite element model of the target structure; according to the service load condition of the target structure, a fatigue load spectrum and simulation parameters are set, fatigue simulation is conducted on the crack propagation analysis model through the fatigue load spectrum and the simulation parameters, and enhancement effect parameters during resonance are obtained; the crack propagation distance is determined based on the enhancement effect parameters during resonance and the fatigue crack propagation model, the problem that the accuracy of crack propagation analysis of the rotating structure under the resonance condition is low is solved, and the accuracy of crack propagation analysis of the rotating structure under the resonance condition is improved.

Description

Technical Field

[0001] The present invention relates to the field of fatigue and dynamic technology, and in particular to a method, device, equipment and storage medium for determining crack extension. Background Art

[0002] The crack propagation of rotating structures in the resonance region is the key content of its damage tolerance analysis. For rotating structures with damage defects, analyzing the crack propagation process under high / low cycle fatigue loads during service and calculating the crack propagation life are the main links of the damage tolerance analysis of rotating structures.

[0003] Rotating structures such as engines, for example, the rotating blades of the compression chamber of an aircraft engine, will be subjected to low cycle fatigue (LCF) loads due to centrifugal force, temperature loads and assembly loads during service, as well as high cycle fatigue (HCF) loads due to blade resonance caused by aerodynamic excitation, mechanical vibration, airfoil flutter and acoustic excitation.

[0004] In the existing crack propagation analysis methods or professional software, many analysis methods ignore the crack enhancement phenomenon in the resonance region, or only approximate it by equivalent low-cycle loads of specified magnitude, resulting in low accuracy of crack propagation analysis of rotating structures. Summary of the invention

[0005] The present invention provides a crack extension determination method, device, equipment and storage medium to solve the problem of low accuracy of crack extension analysis of a rotating structure under resonance.

[0006] According to one aspect of the present invention, a method for determining crack extension is provided, the method comprising:

[0007] According to the resonance theory in vibration mechanics and the fatigue crack growth rate model, a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition is constructed;

[0008] Constructing a crack propagation analysis model of the target structure based on the finite element model of the target structure;

[0009] According to the service load conditions of the target structure, the fatigue load spectrum and simulation parameters are set, and fatigue simulation is performed on the crack growth analysis model through the fatigue load spectrum and simulation parameters to obtain the enhancement effect parameters at resonance;

[0010] The crack propagation distance is determined based on the enhancement effect parameters at resonance and the fatigue crack growth model.

[0011] According to another aspect of the present invention, there is provided a crack extension determination device, the device comprising:

[0012] Fatigue crack growth model building module, which is used to build a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition according to the resonance theory and fatigue crack growth rate model in vibration mechanics;

[0013] A crack propagation analysis model building module is used to build a crack propagation analysis model of a target structure according to a finite element model of the target structure;

[0014] The module for obtaining the parameters of the enhancement effect at resonance is used to set the fatigue load spectrum and simulation parameters according to the service load conditions of the target structure, perform fatigue simulation on the crack propagation analysis model through the fatigue load spectrum and simulation parameters, and obtain the parameters of the enhancement effect at resonance;

[0015] The crack extension distance determination module is used to determine the crack extension distance based on the enhancement effect parameters at resonance and the fatigue crack extension model.

[0016] According to another aspect of the present invention, there is provided an electronic device, the electronic device comprising:

[0017] at least one processor; and

[0018] a memory communicatively connected to at least one processor; wherein,

[0019] The memory stores a computer program that can be executed by at least one processor. The computer program is executed by at least one processor so that the at least one processor can execute the crack extension determination method according to any embodiment of the present invention.

[0020] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the crack extension determination method of any embodiment of the present invention when executed.

[0021] The technical solution of the embodiment of the present invention is to construct a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition according to the resonance theory and fatigue crack growth rate model in vibration dynamics. The resonance theory and fatigue crack growth rate model in vibration dynamics provide comprehensive data support for the construction of the fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition, and improve the generalization of the fatigue crack growth model; construct a crack growth analysis model of the target structure according to the finite element model of the target structure to provide data support for subsequent analysis; set fatigue load spectrum and simulation parameters according to the service load conditions of the target structure, perform fatigue simulation on the crack growth analysis model through the fatigue load spectrum and simulation parameters, obtain the enhanced effect parameters at resonance, perform fatigue simulation on the crack growth analysis model through the fatigue load spectrum and simulation parameters, so that the enhanced effect parameters at resonance are more consistent with the actual situation of the target structure; determine the crack growth distance based on the enhanced effect parameters at resonance and the fatigue crack growth model, solve the problem of low accuracy of crack growth analysis of the target structure under resonance, and improve the accuracy of crack growth analysis of the target structure under resonance.

[0022] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 is a flow chart of a method for determining crack extension provided in Embodiment 1 of the present invention;

[0025] Figure 2 is a schematic diagram of a high / low cycle fatigue load superposition provided by an embodiment of the present invention;

[0026] Figure 3 is a schematic diagram of a response model provided by an embodiment of the present invention;

[0027] Figure 4 is a structural schematic diagram of a finite element model of a target structure provided by an embodiment of the present invention;

[0028] Figure 5 It is a schematic diagram of setting a fatigue load spectrum in fatigue crack analysis software provided by an embodiment of the present invention;

[0029] Figure 6 is a schematic diagram of a stress intensity factor under high / low cycle fatigue load superposition response enhancement processed according to a rain flow counting method provided by an embodiment of the present invention;

[0030] Figure 7 is a schematic diagram of crack propagation under enhanced high / low cycle fatigue load superposition response provided by an embodiment of the present invention;

[0031] Figure 8 is a flow chart of a method for determining crack extension provided in Embodiment 2 of the present invention, and this embodiment is an optimization of the above embodiment;

[0032] Fig. 9 is a structural schematic diagram of a crack extension determination device provided in Embodiment 3 of the present invention;

[0033] Fig.10 It is a structural schematic diagram of an electronic device provided in Embodiment 4 of the present invention. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0036] Embodiment 1

[0037] Figure 1This is a flow chart of a crack extension determination method provided in the first embodiment of the present invention. This embodiment is applicable to the case of improving the accuracy of crack extension analysis of a target structure. The method can be executed by a crack extension determination device. The crack extension determination device can be implemented in the form of hardware and / or software. The crack extension determination device can be configured in an electronic device provided in the embodiment of the present invention. The electronic device can be a server, a computer or a mobile terminal. For example, the mobile terminal can be a mobile phone, a tablet computer, etc. Figure 1 As shown, the method includes:

[0038] S110. Based on the resonance theory in vibration mechanics and the fatigue crack growth rate model, a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition is constructed.

[0039] In this embodiment, the resonance theory in vibration mechanics refers to the fact that when the external excitation frequency of the target structure is equal to the natural frequency of the target structure itself, the target structure can generate large-amplitude vibration. The fatigue crack growth rate model can be understood as a model used to describe the increment of crack length per unit time under fatigue load, including but not limited to the Paris model, Walker model and Forman model. Optionally, the fatigue crack growth rate model can be: Among them, ΔK is the stress intensity factor amplitude and R is the stress ratio.

[0040] The fatigue crack growth model can be understood as a model used to describe the size of fatigue crack initiation and growth in the target structure under the superposition response enhancement of high / low cycle fatigue loads. For example, see Figure 2 , Figure 2 It is a schematic diagram of a high / low cycle fatigue load superposition provided by an embodiment of the present invention, wherein LC represents a static load step, LC1, LC2, LC3 and LC4 represent low cycle load steps, and LC5 and LC6 represent high / low cycle fatigue load superposition load steps.

[0041] Optionally, a response model is constructed based on the resonance theory in vibration mechanics. The response model is a response model of the stress intensity factor and load frequency of the target structure. The response model includes: Where K represents the stress intensity factor, K0 represents the enhancement effect parameter at resonance, represents the normalized angular velocity; the fatigue crack growth rate model is obtained, and based on the fatigue crack growth rate model and the response model, a fatigue crack growth model under high / low cycle fatigue load superposition response enhancement is constructed.

[0042] Specifically, the response model can be understood as a model that describes the relationship between the stress intensity factor and the load frequency of the target structure under the superposition response enhancement of high / low cycle fatigue loads. For example, see Figure 3 , Figure 3 3 is a schematic diagram of a response model provided by an embodiment of the present invention, wherein the abscissa represents the normalized angular velocity, and the ordinate represents the stress intensity factor under the enhanced response of high / low cycle fatigue load superposition.

[0043] The fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition can be constructed based on the resonance theory and fatigue crack growth rate model in vibration mechanics. For example, for the classic "mass-spring-damper" system, its forced vibration amplitude response near the resonance region can be expressed by the regularized formula:

[0044]

[0045] Among them, A represents the amplitude of vibration, A max represents the amplitude at resonance, ξ represents the critical damping ratio, Ω represents the angular velocity regularized by the critical angular velocity ω0, and Ω can be calculated by the following formula:

[0046]

[0047] Where ω0 represents the critical angular velocity, and ω represents the angular velocity of the target structure.

[0048] For a target structure including cracks, the stress intensity factor at the crack front can be calculated using the following formula:

[0049]

[0050] Where K0 represents the enhancement effect parameter at resonance. The normalized angular velocity It can be calculated by the following formula:

[0051]

[0052] Substituting the above formula into the formula of the stress intensity factor at the crack front, we can obtain:

[0053]

[0054] Expanding the above formula, assuming ξ<<1 to eliminate high-order terms, the relationship between stress intensity factor and load frequency can be obtained as follows:

[0055]

[0056] The relationship between stress intensity factor and loading frequency is used as the response model.

[0057] The crack extension distance can be calculated by the integral expression of the fatigue crack growth rate model:

[0058]

[0059] in, represents the fatigue crack growth rate model, f is the vibration frequency, t th ΔK is equal to the threshold value of crack extension ΔK th moment.

[0060] During the passage through the resonant frequency point, there is a constant angular acceleration α, so the angular velocity ω at any time t can be calculated by the following formula:

[0061] ω=ω0+αt;

[0062] Substituting the above formula into the normalized angular velocity From the formula, we can get:

[0063]

[0064] The vibration frequency of the target structure can be calculated using the following formula:

[0065]

[0066] Among them, f represents the vibration frequency, m represents the engine order, and the formula and formula Substitute into the formula Using the symmetry of the integral formula about zero, the fatigue crack growth model is obtained:

[0067]

[0068] Among them, Δa is the expansion distance, m is the engine order; ξ is the critical damping ratio; α is the angular acceleration; ω0 is the critical angular velocity; ΔK is the stress intensity factor amplitude, R is the stress ratio, is the end position of crack extension during the crossing period; is the normalized angular velocity.

[0069] Based on the resonance theory and fatigue crack growth rate model in vibration mechanics, a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition is constructed. The resonance theory and fatigue crack growth rate model in vibration mechanics provide comprehensive data support for the construction of the fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition, and improve the generalization of the fatigue crack growth model.

[0070] S120. Construct a crack propagation analysis model of the target structure according to the finite element model of the target structure.

[0071] In this embodiment, the finite element model can discretize the target structure into a three-dimensional simulation model of a finite number of parts, and perform simulation analysis on the finite element model to determine the simulation analysis result of the target structure, and the analysis result includes one or more of the dangerous point location and the principal stress direction. For example, see Figure 4 , Figure 4 It is a structural schematic diagram of a finite element model of a target structure provided in an embodiment of the present invention. The target structure intercepts a 40° sector-shaped area in the circumferential direction and applies symmetrical boundary conditions on the sector-shaped section.

[0072] The crack propagation analysis model can be understood as a simulation model for crack analysis of the target structure, for example, it can be a finite element model with cracks introduced, and the crack propagation analysis model of the target structure can be constructed based on the finite element model of the target structure and the simulation analysis results of the finite element model. For example, by establishing a finite element model for the target structure, in the process of applying high / low cycle fatigue loads to the target structure, the stress magnitude inside the target structure is analyzed, the position corresponding to the maximum stress is used as the danger point position, and cracks are introduced at the danger point position of the finite element model to obtain the crack propagation analysis model of the target structure.

[0073] In some embodiments, the cracks referenced at the dangerous point position may be pre-set, that is, the properties of the introduced cracks are the same. In some embodiments, the cracks referenced at the dangerous point position may be determined based on the simulation analysis results of the finite element model, that is, the properties of the cracks are positively correlated with the stress magnitude received at the dangerous point position.

[0074] S130. According to the service load conditions of the target structure, a fatigue load spectrum and simulation parameters are set, and fatigue simulation is performed on the crack propagation analysis model through the fatigue load spectrum and simulation parameters to obtain enhancement effect parameters during resonance.

[0075] In this embodiment, the service load condition can be understood as the load condition determined by the actual service demand of the target structure. The fatigue load spectrum can be understood as describing the change of stress of the target structure under the action of fatigue load over time, and the fatigue load spectrum can be set according to the service load condition of the target structure. For example, the service load condition of the target structure can be statistically analyzed, the change law of fatigue load over time can be statistically analyzed, and the fatigue load spectrum can be set according to the change law. The simulation parameters can be understood as the parameters required for fatigue simulation of the crack propagation analysis model, including but not limited to the resonant frequency of the target structure. The enhancement effect parameters at resonance can be understood as the stress intensity factor at the critical angular velocity, which can be obtained by fatigue simulation of the fatigue crack propagation model. For example, the fatigue load spectrum, simulation parameters and crack propagation analysis model are respectively input into the fatigue crack analysis software for simulation to obtain the enhancement effect parameters at resonance. For example, see Figure 5 , Figure 5This is a schematic diagram of setting a fatigue load spectrum in a fatigue crack analysis software provided by an embodiment of the present invention. The service load conditions are determined according to the actual service requirements of the target structure, and the service load conditions of the target structure are statistically analyzed. The variation law of the fatigue load over time is statistically analyzed, and the fatigue load spectrum is set according to the variation law of the fatigue load over time. The crack propagation analysis model is fatigue simulated by the fatigue load spectrum and simulation parameters to obtain the enhancement effect parameters at resonance. The enhancement effect parameters at resonance are more in line with the actual situation of the target structure, thereby improving the accuracy of the crack propagation analysis of the target structure.

[0076] S140. Determine the crack propagation distance based on the enhancement effect parameters at resonance and the fatigue crack propagation model.

[0077] In this embodiment, based on the enhancement effect parameters at resonance obtained from fatigue simulation, the stress intensity factor amplitude, stress ratio and the end position of crack extension during the crossing period can be calculated. By substituting the stress intensity factor amplitude, stress ratio and the end position of crack extension during the crossing period into the fatigue crack extension model, the crack extension distance can be obtained.

[0078] Optional fatigue crack growth models include:

[0079] Among them, Δa is the expansion distance, m is the engine order; ξ is the critical damping ratio; α is the angular acceleration; ω0 is the critical angular velocity; ΔK is the stress intensity factor amplitude, R is the stress ratio, is the end position of crack extension during the crossing period; is the normalized angular velocity; ΔK, R and They are determined based on the enhancement effect parameters at resonance.

[0080] in, Represents the fatigue crack growth rate model, calculates the integral of the fatigue crack growth rate model between the start time of crack growth during the crossing period and the end time of crack growth during the crossing period, and converts it into Fatigue crack growth model with ΔK, R and It can be calculated by the following expression:

[0081]

[0082]

[0083] Among them, K max Indicates the maximum value of the stress intensity factor, K min Represents the minimum value of the stress intensity factor, K s represents the stress intensity factor generated by static load, K0 represents the enhancement effect parameter at resonance, represents the normalized angular velocity, ξ is the critical damping ratio, Ω represents the angular velocity regularized with the critical angular velocity, ω0 represents the critical angular velocity, and ω represents the angular velocity.

[0084] The engine order m, critical damping ratio ξ, critical angular velocity ω0, angular acceleration α and the calculated ΔK, R and Substitute into the fatigue crack growth model The expansion distance Δa can be obtained.

[0085] Optionally, the method also includes: determining the number of fatigue cycles corresponding to the fatigue load spectrum, and the corresponding relationship between the number of fatigue cycles and the crack propagation analysis step; for any crack propagation analysis step, performing fatigue simulation on the crack propagation analysis model corresponding to the current crack propagation analysis step based on the fatigue load spectrum, and obtaining the enhancement effect parameters at resonance corresponding to the current crack propagation analysis step; determining the crack propagation distance corresponding to the current crack propagation analysis step based on the enhancement effect parameters at resonance corresponding to the current crack propagation analysis step and the fatigue crack propagation model; updating the crack propagation analysis model based on the crack propagation distance corresponding to the current crack propagation analysis step, and obtaining the crack propagation analysis model corresponding to the next crack propagation analysis step, until all crack propagation analysis steps are completed and the crack propagation distances corresponding to each crack propagation analysis step are obtained.

[0086] Specifically, the number of fatigue cycles can be understood as the number of fatigue load cycles experienced by the target structure, for example, it can be determined according to the rain flow counting method. For example, according to the change of the stress intensity factor in the fatigue load spectrum of the target structure, the maximum and minimum points of the stress intensity factor are determined, and three consecutive extreme points are regarded as one fatigue cycle. For example, the fatigue load change corresponding to three consecutive minimum points, maximum points and minimum points can be regarded as one fatigue cycle. It can be set according to needs, and there is no limitation here. By analogy, multiple fatigue cycles are determined. For example, see Figure 6 , Figure 6 It is a schematic diagram of a stress intensity factor under the enhanced high / low cycle fatigue load superposition response processed according to the rain flow counting method provided by an embodiment of the present invention. The crack propagation analysis step can be understood as the unit step length for crack propagation analysis of the target structure. There is a corresponding relationship between the crack propagation analysis step and the number of fatigue cycles, including but not limited to a proportional relationship and a multiple relationship. For example, the number of fatigue cycles corresponding to the fatigue load spectrum is k, and each crack propagation analysis step can correspond to k / m cycles; or, each crack propagation analysis step can correspond to n*k cycles. The correspondence between the crack propagation analysis step and the number of fatigue cycles is preset.

[0087] For any crack propagation analysis step, the crack propagation analysis model, fatigue load spectrum and simulation parameters corresponding to the current crack propagation analysis step are respectively input into the fatigue crack analysis software for simulation, and the enhancement effect parameters at resonance corresponding to the current crack propagation analysis step are obtained. The stress intensity factor amplitude, stress ratio and the end position of crack propagation during the crossing period are calculated based on the enhancement effect parameters at resonance corresponding to the current crack propagation analysis step. The stress intensity factor amplitude, stress ratio and the end position of crack propagation during the crossing period are input into the fatigue crack propagation model to obtain the crack propagation distance corresponding to the current crack propagation analysis step. A new crack is introduced based on the crack propagation distance corresponding to the current crack propagation analysis step to update the crack propagation analysis model and obtain the crack propagation analysis model corresponding to the next crack propagation analysis step. This process is repeated until all crack propagation analysis steps are completed and the crack propagation distances corresponding to each crack propagation analysis step are obtained. For example, see Figure 7 , Figure 7 It is a schematic diagram of crack propagation under enhanced high / low cycle fatigue load superposition response provided by an embodiment of the present invention.

[0088] Optionally, the crack growth analysis model corresponding to the first crack growth analysis step includes an initial crack; the crack in the crack growth analysis model corresponding to the non-first crack growth analysis step is determined based on the crack growth distance corresponding to the previous crack growth analysis step and the crack growth direction corresponding to the crack growth criterion.

[0089] Specifically, for the first crack extension analysis step, the initial crack in the crack extension analysis model can be determined based on the finite element model of the target structure. For example, based on the finite element model of the target structure, the dangerous point position of the target structure is determined, and the initial crack is introduced at the dangerous point position to obtain the crack extension analysis model corresponding to the first crack extension analysis step. For non-first crack extension analysis steps, the crack in the crack extension analysis model can be determined based on the crack extension distance corresponding to the previous crack extension analysis step and the crack extension direction corresponding to the crack extension criterion. The crack extension criterion includes, but is not limited to, the stress intensity factor criterion and the maximum circumferential tensile stress crack extension criterion. For example, the principal stress direction is determined according to the crack propagation criterion. The principal stress direction can be understood as the direction corresponding to the maximum principal stress inside the target structure. The principal stress direction is used as the crack propagation direction. According to the crack propagation distance and crack propagation direction corresponding to the previous crack propagation analysis step, based on the crack in the crack propagation analysis model corresponding to the previous crack propagation analysis step, according to the crack propagation distance and crack propagation direction corresponding to the previous crack propagation analysis step, the crack in the crack propagation analysis model corresponding to the previous crack propagation analysis step is updated to obtain the crack in the crack propagation analysis model corresponding to the current crack propagation analysis step.

[0090] The technical solution of this embodiment is to construct a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition according to the resonance theory and fatigue crack growth rate model in vibration dynamics. The resonance theory and fatigue crack growth rate model in vibration dynamics provide comprehensive data support for the construction of the fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition, thereby improving the accuracy of the fatigue crack growth model; to construct a crack growth analysis model of the target structure according to the finite element model of the target structure, thereby providing data support for subsequent analysis; to set the fatigue load spectrum and simulation parameters according to the service load conditions of the target structure, to perform fatigue simulation on the crack growth analysis model through the fatigue load spectrum and simulation parameters, to obtain the enhanced effect parameters at resonance, to perform fatigue simulation on the crack growth analysis model through the fatigue load spectrum and simulation parameters, thereby making the enhanced effect parameters at resonance more consistent with the actual situation of the target structure; to determine the crack growth distance based on the enhanced effect parameters at resonance and the fatigue crack growth model, thereby solving the problem of low accuracy of crack growth analysis of rotating structures under resonance, thereby improving the accuracy of crack growth analysis of rotating structures under resonance.

[0091] Embodiment 2

[0092] Figure 8 1 is a flow chart of a method for determining crack extension provided by Embodiment 2 of the present invention. This embodiment is an optimization of the above embodiment. Figure 8 As shown, the method includes:

[0093] S210. Based on the resonance theory in vibration mechanics and the fatigue crack growth rate model, a fatigue crack growth model under the enhanced high / low cycle fatigue load superposition response is constructed.

[0094] S220. Perform finite element analysis on the finite element model of the target structure to determine the location of the dangerous point and the direction of the principal stress.

[0095] In this embodiment, a finite element analysis is performed on the finite element model of the target structure, the target structure is divided into a finite number of parts, and a finite element analysis is performed on each part. In the process of applying high / low cycle fatigue loads to the target structure, the stress magnitude inside the target structure is analyzed, and the position corresponding to the maximum stress is used as the danger point position. The principal stress direction is determined according to the crack propagation criterion, for example, the principal stress direction is determined according to the crack propagation criterion, and the principal stress direction is used as the crack propagation direction. A finite element model of the target structure is established and a finite element analysis is performed to obtain the danger point position and the principal stress direction, which provides data support for the construction of the crack propagation analysis model.

[0096] S230. Introduce cracks into the finite element model of the target structure based on the location of the danger point and the direction of the principal stress, and obtain a crack propagation analysis model of the target structure.

[0097] In this embodiment, the crack propagation analysis model of the target structure can be obtained by introducing cracks into the finite element model of the target structure according to the position of the dangerous point and the direction of the principal stress. For example, the position of the dangerous point can be used as the starting position of the crack, and the direction of the principal stress can be used as the direction of the crack. In the finite element model of the target structure, cracks are introduced according to the position of the dangerous point and the direction of the principal stress, and the crack propagation analysis model of the target structure can be obtained. According to the position of the dangerous point and the direction of the principal stress, cracks are introduced into the finite element model of the target structure, thereby improving the accuracy of the crack propagation analysis model.

[0098] S240, according to the service load conditions of the target structure, set the fatigue load spectrum and simulation parameters, perform fatigue simulation on the crack propagation analysis model through the fatigue load spectrum and simulation parameters, and obtain the enhancement effect parameters at resonance.

[0099] Optionally, the simulation parameters include resonance frequency, speed acceleration, engine order and damping ratio; wherein, the resonance frequency is determined based on the resonance vibration mode corresponding to the high-cycle load, and the resonance vibration mode corresponding to the high-cycle load is obtained by matching the dangerous point position and the principal stress direction; the speed acceleration is determined based on the speed data in the service load condition of the target structure; the engine order and the damping ratio are determined based on the structural type of the target structure, respectively.

[0100] Specifically, the fatigue crack analysis software stores multiple dangerous point positions and principal stress directions, corresponding resonance vibration modes, and resonance frequencies corresponding to the resonance vibration modes. Different dangerous point positions and principal stress directions correspond to different resonance vibration modes, and different resonance vibration modes correspond to different resonance frequencies. The similarities between the dangerous point position and principal stress direction of the target structure and multiple dangerous point positions and principal stress directions are calculated respectively. By comparing the sizes of multiple similarities, the maximum similarity and the dangerous point position and principal stress direction corresponding to the maximum similarity are determined. The corresponding resonance vibration mode is determined according to the dangerous point position and principal stress direction corresponding to the maximum similarity, and the corresponding resonance frequency can be determined according to the resonance vibration mode. The speed acceleration can be determined according to the speed data in the service load condition of the target structure, for example, the change in the speed data within a preset time can be calculated. When the structural type of the target structure is determined, the engine order and damping ratio can be determined according to the structural type of the target structure. Under the condition of high / low cycle fatigue load superposition response enhancement, the engine order and damping ratio remain unchanged. Target structures of different structures have different engine orders and damping ratios.

[0101] S250. Determine the crack propagation distance based on the enhancement effect parameters at resonance and the fatigue crack propagation model.

[0102] In this embodiment, the stress intensity factor amplitude ΔK, stress ratio R and the end position of crack extension during the crossing period are calculated according to the enhancement effect parameters at resonance obtained by fatigue simulation. ΔK, R, and The calculation formula is as follows:

[0103]

[0104]

[0105] Among them, K max Indicates the maximum value of the stress intensity factor, K min Represents the minimum value of the stress intensity factor, K s represents the stress intensity factor generated by static load, K0 represents the enhancement effect parameter at resonance, represents the normalized angular velocity, ΔK th represents the threshold value of crack extension, ξ is the critical damping ratio, Ω represents the angular velocity regularized by the critical angular velocity, ω0 represents the critical angular velocity, and ω represents the angular velocity.

[0106] The engine order m, critical damping ratio ξ, critical angular velocity ω0, angular acceleration α and the calculated ΔK, R and Substitute into the fatigue crack growth model The expansion distance Δa can be obtained.

[0107] The technical solution of this embodiment is to construct a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition according to the resonance theory in vibration mechanics and the fatigue crack growth rate model. The resonance theory in vibration mechanics and the fatigue crack growth rate model provide comprehensive data support for the construction of the fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition, thereby improving the accuracy of the fatigue crack growth model. The finite element model of the target structure is subjected to finite element analysis to determine the location of the danger point and the direction of the principal stress, thereby providing data support for subsequent analysis. The crack growth model is introduced into the finite element model of the target structure based on the location of the danger point and the direction of the principal stress. , the crack propagation analysis model of the target structure is obtained, which improves the accuracy of the crack propagation analysis model of the target structure; according to the service load conditions of the target structure, the fatigue load spectrum and simulation parameters are set, and the crack propagation analysis model is fatigue simulated through the fatigue load spectrum and simulation parameters to obtain the enhancement effect parameters at resonance, and the crack propagation analysis model is fatigue simulated through the fatigue load spectrum and simulation parameters, so that the enhancement effect parameters at resonance are more consistent with the actual situation of the target structure; the crack propagation distance is determined based on the enhancement effect parameters at resonance and the fatigue crack propagation model, which improves the accuracy of crack propagation analysis of the rotating structure under resonance.

[0108] Embodiment 3

[0109] Fig. 9 Schematic diagram of a crack extension determination device provided in Embodiment 3 of the present invention. Fig. 9As shown, the device comprises:

[0110] A fatigue crack growth model building module 310 is used to build a fatigue crack growth model under the condition of high / low cycle fatigue load superposition response enhancement according to the resonance theory and fatigue crack growth rate model in vibration mechanics;

[0111] A crack propagation analysis model building module 320 is used to build a crack propagation analysis model of a target structure according to a finite element model of the target structure;

[0112] The enhancement effect parameter acquisition module 330 at resonance is used to set the fatigue load spectrum and simulation parameters according to the service load conditions of the target structure, perform fatigue simulation on the crack growth analysis model through the fatigue load spectrum and simulation parameters, and obtain the enhancement effect parameters at resonance;

[0113] The crack extension distance determination module 340 is used to determine the crack extension distance based on the enhancement effect parameters at resonance and the fatigue crack extension model.

[0114] Based on the above embodiment, optionally, the fatigue crack growth model construction module 310 is further used to: construct a response model based on the resonance theory in vibration mechanics, the response model is a response model of the stress intensity factor and the load frequency of the target structure, and the response model includes: Where K represents the stress intensity factor, K0 represents the enhancement effect parameter at resonance, represents the normalized angular velocity; obtain the fatigue crack growth rate model, and based on the fatigue crack growth rate model and the response model, construct a fatigue crack growth model under high / low cycle fatigue load superposition response enhancement.

[0115] Optionally, the crack extension analysis model construction module 320 is also used to: perform finite element analysis on the finite element model of the target structure to determine the danger point location and principal stress direction; introduce cracks into the finite element model of the target structure based on the danger point location and principal stress direction to obtain a crack extension analysis model of the target structure.

[0116] Optionally, the fatigue load spectrum includes resonance frequency, speed acceleration, engine order and damping ratio; wherein, the resonance frequency is determined based on the resonance vibration mode corresponding to the high-cycle load, and the resonance vibration mode corresponding to the high-cycle load is obtained by matching the dangerous point position and the principal stress direction; the speed acceleration is determined based on the speed data in the service load condition of the target structure; the engine order and the damping ratio are determined based on the structural type of the target structure, respectively.

[0117] Optional fatigue crack growth models include: Among them, Δa is the expansion distance, m is the engine order, ξ is the damping ratio, α is the angular acceleration, ω0 is the critical angular velocity, ΔK is the stress intensity factor amplitude, R is the stress ratio, is the end position of crack extension during the crossing period; is the normalized angle; ΔK, R and They are determined based on the enhancement effect parameters at resonance.

[0118] Optionally, the crack extension distance determination module 340 is also used to: determine the number of fatigue cycles corresponding to the fatigue load spectrum, and the corresponding relationship between the number of fatigue cycles and the crack extension analysis step; for any crack extension analysis step, perform fatigue simulation on the crack extension analysis model corresponding to the current crack extension analysis step based on the crack extension analysis step to obtain the enhancement effect parameters at resonance corresponding to the current crack extension analysis step; determine the crack extension distance corresponding to the current crack extension analysis step based on the enhancement effect parameters at resonance corresponding to the current crack extension analysis step and the fatigue crack extension model; update the crack extension analysis model based on the crack extension distance corresponding to the current crack extension analysis step to obtain the crack extension analysis model corresponding to the next crack extension analysis step, until all crack extension analysis steps are completed to obtain the crack extension distances corresponding to each crack extension analysis step.

[0119] Optionally, the crack growth analysis model corresponding to the first crack growth analysis step includes an initial crack; the crack in the crack growth analysis model corresponding to the non-first crack growth analysis step is determined based on the crack growth distance corresponding to the previous crack growth analysis step and the crack growth direction corresponding to the crack growth criterion.

[0120] The crack extension determination device provided in the embodiment of the present invention can execute the crack extension determination method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0121] Embodiment 4

[0122] Fig.10 1 is a schematic diagram of the structure of an electronic device provided in Embodiment 4 of the present invention. The electronic device 10 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 may also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, 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 examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0123] like Fig.10As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0124] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0125] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a crack extension determination method.

[0126] In some embodiments, the crack extension determination method may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the crack extension determination method described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to perform the crack extension determination method in any other appropriate manner (e.g., by means of firmware).

[0127] Various implementations 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 chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0128] The computer program for implementing the crack extension determination method of the present invention can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0129] Embodiment 5

[0130] Embodiment 5 of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to cause a processor to execute a crack extension determination method, the method comprising:

[0131] According to the resonance theory in vibration mechanics and the fatigue crack growth rate model, a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition is constructed; according to the finite element model of the target structure, a crack growth analysis model of the target structure is constructed; according to the service load conditions of the target structure, the fatigue load spectrum and simulation parameters are set, and fatigue simulation is performed on the crack growth analysis model through the fatigue load spectrum and simulation parameters to obtain the enhancement effect parameters at resonance; the crack growth distance is determined based on the enhancement effect parameters at resonance and the fatigue crack growth model.

[0132] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0133] To provide interaction with a user, the systems and techniques described herein may 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 a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0134] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0135] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0136] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0137] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for determining crack extension, characterized in that: include: According to the resonance theory in vibration mechanics and the fatigue crack growth rate model, a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition is constructed; Constructing a crack propagation analysis model of the target structure according to the finite element model of the target structure; According to the service load conditions of the target structure, a fatigue load spectrum and simulation parameters are set, and fatigue simulation is performed on the crack propagation analysis model by using the fatigue load spectrum and the simulation parameters to obtain the enhancement effect parameters at resonance; The crack extension distance is determined based on the enhancement effect parameter at the resonance and the fatigue crack extension model.

2. The method according to claim 1, characterized in that The fatigue crack growth model under the condition of high / low cycle fatigue load superposition response enhancement is constructed according to the resonance theory and fatigue crack growth rate model in vibration mechanics, including: Based on the resonance theory in the vibration mechanics, a response model is constructed. The response model is a response model of the stress intensity factor and load frequency of the target structure. The response model includes: Where K represents the stress intensity factor, K0 represents the enhancement effect parameter at resonance, represents the normalized angular velocity; The fatigue crack growth rate model is obtained, and based on the fatigue crack growth rate model and the response model, a fatigue crack growth model under high / low cycle fatigue load superposition response enhancement is constructed.

3. The method according to claim 1, characterized in that The method of constructing a crack propagation analysis model of the target structure according to the finite element model of the target structure comprises: Performing finite element analysis on the finite element model of the target structure to determine the location of the danger point and the direction of the principal stress; A crack is introduced into the finite element model of the target structure based on the position of the danger point and the direction of the principal stress to obtain a crack propagation analysis model of the target structure.

4. The method according to claim 3, characterized in that The simulation parameters include resonance frequency, speed acceleration, engine order and damping ratio; Wherein, the resonance frequency is determined based on the resonance vibration mode corresponding to the high cycle load, and the resonance vibration mode corresponding to the high cycle load is obtained by matching the position of the dangerous point with the direction of the principal stress; The rotational speed acceleration is determined based on rotational speed data in a service load condition of the target structure; The engine order and the damping ratio are determined based on a structural type of the target structure, respectively.

5. The method according to claim 1, characterized in that The fatigue crack growth model includes: Among them, Δa is the expansion distance, m is the engine order; ξ is the critical damping ratio; α is the angular acceleration; ω0 is the critical angular velocity; ΔK is the stress intensity factor amplitude, R is the stress ratio, is the end position of crack extension during the crossing period; is the normalized angular velocity; the ΔK, the R and the They are respectively determined based on the enhancement effect parameters at the resonance.

6. The method according to claim 1, characterized in that The method further comprises: Determining the number of fatigue cycles corresponding to the fatigue load spectrum, and the corresponding relationship between the number of fatigue cycles and the crack growth analysis step; For any of the crack growth analysis steps, fatigue simulation is performed on the crack growth analysis model corresponding to the current crack growth analysis step based on the fatigue load spectrum to obtain the enhancement effect parameter at the resonance corresponding to the current crack growth analysis step; Determining the crack extension distance corresponding to the current crack extension analysis step based on the enhancement effect parameter at resonance corresponding to the current crack extension analysis step and the fatigue crack extension model; The crack propagation analysis model is updated based on the crack propagation distance corresponding to the current crack propagation analysis step to obtain the crack propagation analysis model corresponding to the next crack propagation analysis step, until all crack propagation analysis steps are completed to obtain the crack propagation distances corresponding to each crack propagation analysis step.

7. The method according to claim 6, characterized in that The crack growth analysis model corresponding to the first crack growth analysis step includes the initial crack; The cracks in the crack growth analysis model corresponding to the non-first crack growth analysis step are determined based on the crack growth distance corresponding to the previous crack growth analysis step and the crack growth direction corresponding to the crack growth criterion.

8. A crack extension determination device, characterized in that: include: Fatigue crack growth model building module, which is used to build a fatigue crack growth model under the enhanced response of high / low cycle fatigue load superposition according to the resonance theory and fatigue crack growth rate model in vibration mechanics; A crack propagation analysis model building module, used to build a crack propagation analysis model of the target structure according to a finite element model of the target structure; A module for acquiring parameters of the enhancement effect at resonance, used to set a fatigue load spectrum and simulation parameters according to the service load conditions of the target structure, perform fatigue simulation on the crack propagation analysis model through the fatigue load spectrum and the simulation parameters, and obtain the parameters of the enhancement effect at resonance; A crack extension distance determination module is used to determine the crack extension distance based on the enhancement effect parameter at the resonance and the fatigue crack extension model.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the crack extension determination method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the crack extension determination method according to any one of claims 1 to 7 when executed.

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