Fatigue damage prediction method, system and computer readable storage medium

Abstract

The embodiment of the application provides a kind of fatigue damage prediction method of shaft body and its system and computer readable storage medium, comprising: establishing the shaft body model of shaft body, determine fatigue timing load;Obtain the structural stiffness of multiple positions of shaft body model;According to the structural stiffness of multiple positions, the fatigue timing load is corrected, and the optimized fatigue timing load after correction is obtained;And in the shaft body model loading optimization fatigue timing load, by finite element simulation, the fatigue damage value of shaft body model is obtained by prediction.This application's fatigue damage prediction method of shaft body is high in accuracy.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of mechanical transmission, and in particular to a fatigue damage prediction method, a system thereof and a computer readable storage medium. BACKGROUND

[0002] With the gradual depletion of energy such as coal and oil, human beings pay more and more attention to the use of renewable energy. As a clean and renewable energy, wind energy is increasingly valued by countries around the world. With the continuous development of wind power technology, wind turbine generators are increasingly used in power systems. Wind turbine generators are large-scale equipment that convert wind energy into electrical energy, and are usually set up in areas rich in wind energy resources.

[0003] Currently, wind turbine generators are installed at wind ports in high mountains, wilderness, beaches, islands and the like, and are subjected to the impact of irregularly changing direction and load wind and strong gusts, and are affected by scorching heat and extreme temperature differences all year round. The various components of the wind turbine generator are prone to failure. The main shaft, which is an important component of the wind turbine generator, needs to be subjected to fatigue damage prediction. Conventional fatigue damage prediction methods use fatigue time sequence loads with low accuracy for simulation, and the results obtained have a large difference from the actual results, and the simulation results are poor. SUMMARY

[0004] An object of embodiments of the present application is to provide a fatigue damage prediction method, a system thereof and a computer readable storage medium with high accuracy.

[0005] One aspect of embodiments of the present application provides a fatigue damage prediction method, characterized in that the fatigue damage prediction method comprises:

[0006] establishing a shaft model of the shaft body, and determining fatigue time sequence loads;

[0007] obtaining structural stiffnesses of a plurality of positions of the shaft model;

[0008] correcting the fatigue time sequence loads according to the structural stiffnesses of the plurality of positions to obtain optimized fatigue time sequence loads; and

[0009] loading the optimized fatigue time sequence loads on the shaft model, and predicting fatigue damage values of the shaft model through finite element simulation.

[0010] determining a correction coefficient according to the structural stiffnesses of the plurality of positions;

[0011] correcting the fatigue time sequence loads according to the correction coefficient to obtain the optimized fatigue time sequence loads.

[0012] Optionally, the fatigue time sequence load is loaded in rotation around a central axis of the shaft body model, and the fatigue load at a plurality of time points is included.

[0013] The correction coefficient is determined according to the structural rigidity of the first reference position.

[0014] A first reference position at the current time point is determined according to an azimuth angle of the fatigue load at the current time point.

[0015] The correction coefficient of the fatigue load at the current time point is determined according to the structural rigidity of the first reference position.

[0016] The fatigue time sequence load is corrected according to the correction coefficient to obtain an optimized fatigue time sequence load after correction.

[0017] The fatigue load at the current time point is corrected according to the correction coefficient of the fatigue load at the current time point to obtain an optimized fatigue load at the current time point after correction, and the optimized fatigue time sequence load includes optimized fatigue loads at a plurality of time points.

[0018] Optionally, the correction coefficient of the fatigue load at the current time point is determined according to the structural rigidity of the first reference position.

[0019] A second reference position is determined according to an azimuth angle of the fatigue load at a next time point of the current time point.

[0020] The correction coefficient of the fatigue load at the current time point is determined according to the structural rigidity of the first reference position and the second reference position.

[0021] Optionally, the structural rigidity of a plurality of positions of the shaft body model is obtained by:

[0022] A test load is applied to the shaft body model to obtain test stresses at the plurality of positions of the shaft body model.

[0023] The correction coefficient of the fatigue load at the current time point is determined according to the test stresses of the first reference position and the second reference position.

[0024] The correction coefficient of the fatigue load at the current time point is determined according to the test stresses of the first reference position and the second reference position.

[0025] Optionally, the correction coefficient of the fatigue load at the current time point is determined according to the test stresses of the first reference position and the second reference position.

[0026] determining a ratio of test stresses of the second reference position and the first reference position as the correction coefficient of the fatigue load at the current time.

[0027] Optionally, the fatigue damage prediction method further comprises:

[0028] performing finite element meshing on the shaft body model to obtain a finite element mesh;

[0029] determining a second reference position according to an azimuth angle of the fatigue load at a next time of the current time, comprises:

[0030] if the first reference position and the second reference position are both in a first cell of the finite element mesh, determining a second cell adjacent to the first cell as a new second reference position;

[0031] determining the correction coefficient of the fatigue load at the current time according to structural stiffnesses of the first reference position and the second reference position, comprises:

[0032] determining the correction coefficient of the fatigue load at the current time according to structural stiffnesses of the first reference position and the new second reference position.

[0033] Optionally, the obtaining of the structural stiffnesses of the plurality of positions of the shaft body model comprises: applying a test load to the shaft body model to obtain test stresses at the plurality of positions of the shaft body model;

[0034] determining the structural stiffnesses of the plurality of positions of the shaft body model according to the test stresses at the plurality of positions.

[0035] Optionally, the fatigue time sequence load comprises fatigue time sequence load components in a plurality of directions, the optimized fatigue time sequence load comprises optimized fatigue time sequence load components in a plurality of directions, and the correcting of the fatigue time sequence load according to the structural stiffnesses of the plurality of positions to obtain the optimized fatigue time sequence load after correction comprises:

[0036] correcting the plurality of fatigue time sequence load components according to the structural stiffnesses of the plurality of positions to obtain the plurality of optimized fatigue time sequence load components after correction;

[0037] the loading of the optimized fatigue time sequence load on the shaft body model and the prediction of the fatigue damage value of the shaft body model through finite element simulation, comprises:

[0038] the loading of the optimized fatigue time sequence load components on the shaft body model and the prediction of fatigue damage value components of the shaft body model through finite element simulation, the fatigue damage value of the shaft body model being a sum of the fatigue damage value components of the shaft body model.

[0039] Another aspect of this application provides a fatigue damage prediction system, which includes one or more processors for implementing the above-described fatigue damage prediction method.

[0040] Another aspect of this application provides a computer-readable storage medium. The computer-readable storage medium stores a program that, when executed by a processor, implements the fatigue damage prediction method described above.

[0041] The fatigue damage prediction method of this application establishes a shaft model of the entire spindle, analyzes the stiffness of different positions of the shaft model, and corrects the fatigue time-series load. This eliminates the influence of the bearing housing on the structural stiffness of the shaft during shaft modeling. The fatigue damage obtained by using the corrected optimized fatigue time-series load is uniform along the circumference of the shaft, which is consistent with the actual situation of uniform wear of the shaft due to continuous rotation during operation. The fatigue damage prediction method of this application has high accuracy. Attached Figure Description

[0042] Figure 1 This is a flowchart of a fatigue damage prediction method according to an embodiment of this application;

[0043] Figure 2 for Figure 1 The flowchart of step S3 in the fatigue damage prediction method shown is as follows.

[0044] Figure 3 for Figure 1 The figure shows a comparison of the fatigue time-series load before and after the correction of the fatigue damage prediction method.

[0045] Figure 4 for Figure 1 The figure shows a comparison of fatigue simulation results before and after the correction of the fatigue damage prediction method.

[0046] Figure 5 This is a schematic block diagram of a fatigue damage prediction system according to an embodiment of this application. Detailed Implementation

[0047] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses consistent with some aspects of this application as detailed in the appended claims.

[0048] The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Unless otherwise defined, technical terms or scientific terms used in the embodiments of the present application have the meanings commonly understood by one of ordinary skill in the art in the field of the present application. The words "first", "second", and similar terms of distinction do not necessarily imply a serial or chronological order, either temporally or spatially, but are used to distinguish one from another. Similarly, the words "a" and "one" and other singular forms do not limit the phrase following the word, the article "the", or the article "said" to the singular aspect, which means that the phrase can include multiple referencing. The words "front", "back", "lower", and / or "upper" and similar words of location are used for convenience and are not meant to be limiting of a particular position or spatial orientation. The words "include", "comprise", and similar words of inclusion are meant to be equivalent to the words "comprising" and "including" and are meant to be inclusive, not exhaustive. The words "connected" and "coupled" and similar words of physical or logical attachment are meant to be broad enough to include direct and indirect connections and couplings between two or more components, whether or not those components are physically or logically connected or coupled. The words "a" and "one" and other singular forms are intended to include plural forms as well, unless the context clearly indicates otherwise. The term "and / or" as used in the specification and in the claims, means any one of the items, or any combination of the items, that are recited in the "and / or" clause. The terms "comprise", "comprising", "include", "including", and the like, mean "including but not limited to".

[0049] The main shaft of a wind turbine is a rotating component in a wind turbine generator, responsible for connecting the hub and the gearbox. As an important component in a wind turbine, the main shaft needs to be simulated for fatigue damage to predict whether the main shaft is qualified and to predict the service life of the main shaft. The present application provides a fatigue damage prediction method for a shaft body, which can be used for fatigue damage prediction of the main shaft of a wind turbine in some embodiments, and can also be used for fatigue damage prediction of other shaft body components. Based on quasi-static analysis, a finite element method and software tools are applied, a test load is loaded at the center of the hub, mechanical analysis is performed, shaft body stress results are solved, fatigue damage simulation is performed, fatigue damage values are predicted, and safety judgment is performed. Figure 1 A flowchart of the fatigue damage prediction method of an embodiment of the present application. In some embodiments, the fatigue damage prediction method of the present application includes steps S1-S4.

[0050] In step S1, a shaft body model of the shaft body is established, and a fatigue time sequence load is determined. The shaft body model is built according to the actual shape and material of the shaft body, and the shaft body model includes the shaft body and the bearing seat supporting the shaft body. For example, during the operation of the wind turbine, the main shaft is constantly rotating and subjected to a load that changes over time. Since the present application adopts quasi-static analysis, the shaft body model does not rotate during simulation, and the fatigue time sequence load can be loaded around the central axis of the shaft body model. The size of the fatigue time sequence load is obtained according to factors such as the wind turbine model and the wind farm environment. Since the fatigue time sequence load is a load that constantly rotates and changes in size over time, the fatigue time sequence load includes fatigue loads at multiple times, and each fatigue time sequence load at a time corresponds to an azimuth angle when rotating one circle. In this way, the fatigue load method of the present application is applicable to shaft bodies of different structures and different connection modes, has high applicability, and is simple and accurate in prediction.

[0051] In actual operation of the wind turbine, since the main shaft is a rotating part during operation of the unit, the fatigue damage results at different positions around the circumference should be relatively close and should not be significantly different. However, since the fatigue damage prediction method of the present application uses quasi-static analysis, the flanges connected to the rack at both ends of the bearing seat of the wind turbine sometimes have a structure stiffness that is significantly higher than other positions. Stiffness is the ability of a material or structure to resist deformation. In the present application, the structural stiffness refers to the ability of a point or a region to resist deformation under the force on the structure. At this time, if the fatigue time sequence load obtained according to factors such as the wind turbine model and the wind farm environment is used for simulation, the shaft body is not easy to deform at this position due to the sudden increase in the structural stiffness of the bearing seat at this position, and thus is more prone to wear. At this time, the fatigue damage of the main shaft in the circumferential direction is significantly different, which is obviously inconsistent with the fact that the main shaft rotates uniformly. In other embodiments, the main shaft also has the same situation of the fatigue damage of the main shaft in the circumferential direction being significantly different due to different structural stiffness. To this end, the fatigue time sequence load obtained from the past data is corrected to make the fatigue damage simulation result close to the actual damage structure, and the fatigue damage prediction method of the present application can avoid the situation that the fatigue damage of a region of the shaft body and the fatigue damage of positions around the circumference are significantly different due to uneven stiffness of the shaft body model, and objectively assess the true bearing capacity of the main shaft.

[0052] Since the difference of fatigue damage is mainly caused by structural stiffness, the fatigue time sequence load can be corrected according to the structural stiffness of the shaft model. In step S2, the structural stiffness of multiple positions of the shaft model is obtained. The structural stiffness of the shaft model in the present application refers to the overall structural stiffness of the shaft and the bearing seat, and the structural stiffness of the shaft model can be represented by some parameters. In order to correct the fatigue time sequence load, the multiple positions are determined by the azimuth angle of the fatigue time sequence load, and each azimuth angle corresponds to a position, so the multiple positions are arranged in a circumferential direction on the shaft model. In some embodiments, step S2 includes applying a test load to the shaft model, obtaining test stresses of multiple positions on the shaft model, and determining the structural stiffness of the multiple positions of the shaft model according to the test stresses of the multiple positions. The size of the test stress of the multiple positions can reflect the structural stiffness of the corresponding position, and the smaller the test stress, the greater the structural stiffness of the corresponding position. The present application obtains the structural stiffness of different positions in the circumferential direction of the shaft model by obtaining the test stresses of multiple positions on the shaft model, which is accurate and simple in prediction process. In some embodiments, in order to facilitate calculation, the test load is a unit load. In some embodiments, the structural stiffness can also be derived from material properties and structural parameters according to existing methods, as long as it can reflect the resistance to deformation of different regions of the structure.

[0053] In step S3, the fatigue time sequence load is corrected according to the structural stiffness of the multiple positions to obtain the corrected optimal fatigue time sequence load. Since the structural stiffness of the shaft model is different, it can cause a large difference in fatigue damage of the shaft in the circumferential direction, and the fatigue time sequence load can be corrected according to the difference and change trend of the structural stiffness. In some embodiments, step S3 includes steps S31-S32. Figure 2 For Figure 1 The specific flow chart of step S3 of the fatigue damage prediction method shown in the figure.

[0054] In step S31, the correction coefficient is determined according to the structural stiffness of the plurality of positions. In step S32, the fatigue time sequence load is corrected according to the correction coefficient to obtain the optimized fatigue time sequence load. The fatigue time sequence load is a load that rotates and changes in size over time, and the fatigue time sequence load can be divided into fatigue loads at a plurality of time points, and the corrected optimized fatigue time sequence load can also be divided into optimized fatigue loads corresponding to the time points. In the illustrated embodiment, since the fatigue time sequence load includes fatigue loads at a plurality of time points, the optimized fatigue time sequence load includes optimized fatigue loads at a plurality of time points, and the corrected optimized fatigue loads at a plurality of time points correspond one-to-one to the fatigue loads, the fatigue loads at a plurality of time points can be corrected by calculating the correction coefficient therebetween, and the size of the correction coefficient is only related to the shaft body model itself and does not change with the fatigue time sequence load. Thus, the correction coefficient of the present application can be adapted for repeated use, and is still applicable in the case of changing the fatigue time sequence load. The fatigue damage prediction method of the present application is highly adaptable.

[0055] In determining the correction coefficient, different methods can be adopted. In some embodiments, the correction coefficient is determined according to the numerical value of the structural stiffness, and step S31 includes: determining a proportional coefficient according to the structural stiffness of the plurality of positions; determining a first reference position at the current time point according to the azimuth angle of the fatigue load at the current time point; and determining the correction coefficient of the fatigue load at the current time point according to the structural stiffness of the first reference position. The first reference position is one of the plurality of positions in step S2 corresponding to the azimuth angle of the fatigue load at the current time point. Since the structural stiffness of the plurality of positions of the shaft body model is obtained in step S2, a standard data can be preset, and the structural stiffness data of the plurality of positions are compared around the standard data to obtain the proportional coefficient. Multiplying the structural stiffness of the first reference position corresponding to the azimuth angle at the current time point by the proportional coefficient can obtain the correction coefficient of the fatigue load at the current time point, and thus the calculation is simple.

[0056] In other embodiments, the correction coefficient is determined according to the change trend of the structural stiffness. At this time, step S31 includes: determining a second reference position according to the azimuth angle of the fatigue load at the next time point of the current time point; and determining the correction coefficient of the fatigue load at the current time point according to the structural stiffness of the first reference position and the second reference position. The first reference position is one of the plurality of positions in step S2 corresponding to the azimuth angle of the fatigue load at the current time point, and the second reference position is one of the plurality of positions in step S2 corresponding to the azimuth angle of the fatigue load at the next time point of the current time point. By comparing the structural stiffness of the first reference position and the second reference position, the change trend of the structural stiffness is obtained, and thus the correction coefficient is determined according to the change trend of the structural stiffness of the shaft body model, which is more accurate.

[0057] The specific value of the correction coefficient is determined according to the expression of the structural stiffness, and in the illustrated embodiment, the expression of the structural stiffness of the plurality of positions is the size of the test stress, and at this time, step S31 comprises: determining the correction coefficient of the fatigue load at the current time according to the test stresses of the first reference position and the second reference position; determining the ratio of the test stresses of the second reference position and the first reference position as the correction coefficient of the fatigue load at the current time. The formula is as follows formula (1):

[0058]

[0059] In formula (1), M old is the fatigue load at the current time before correction, M new is the optimized fatigue load at the current time after correction, the current time is t1, the next time of the current time is t2, σ θ_t1 is the value of the test stress of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t1, and σ θ_t2 is the value of the test stress of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t2.

[0060] Figure 3 is the comparison diagram of the fatigue time sequence load before correction and the optimized time sequence load after correction of the fatigue damage prediction method shown in Figure 1 Please refer to Figure 3 and formula 1, it can be seen from formula 1 that if the value of the test stress of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t2 is less than the value of the test stress of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t1, it represents that the structural stiffness of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t2 is greater than the structural stiffness of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t1, at this time, the correction coefficient is greater than 1, and the absolute value of the optimized fatigue load at the current time after correction is greater than the absolute value of the fatigue load at the current time before correction, that is, the size of the fatigue load of the corresponding position in the shaft body model corresponding to the azimuth angle of the fatigue time sequence load at t1 is reduced, and vice versa. Figure 4 is the comparison diagram of the fatigue simulation results before and after correction of the fatigue damage prediction method shown in Figure 1 Please refer to Figure 4 Since the fatigue damage value decreases with the decrease of the fatigue load under the condition that the structural stiffness is unchanged, reducing the fatigue load at this position can directly reduce the fatigue damage value of the position with large structural stiffness in the shaft body model, the fatigue time sequence load which is originally large due to distortion is corrected, and the fatigue damage simulation value obtained after such correction is uniform in value on the entire shaft body, and the fatigue damage prediction method of the shaft body is high in accuracy.

[0061] In step S4, the fatigue damage value of the shaft model is obtained by loading the optimized fatigue time history load on the shaft model and through finite element simulation. The prediction process is realized by simulation software. The application does not limit the specific implementation of the correlation between fatigue time history load and stress results, the synthesis of principal stress, rainflow counting and fatigue calculation in the prediction process. The fatigue damage value obtained by the finite element simulation is the fatigue damage value of multiple positions. In other embodiments, steps S2-S3 of the application can be repeated to change the multiple positions of the calculated structural stiffness, thereby obtaining the fatigue damage values of other positions, and finally completing the prediction of the fatigue damage of the shaft. Or the position most prone to failure is selected to calculate the fatigue damage using the fatigue damage prediction method of the application to obtain the service life of the shaft.

[0062] In some embodiments, the fatigue time history load is complex, and the fatigue time history load can be decomposed into multiple directional fatigue time history load components. Correspondingly, the optimized fatigue time history load includes multiple directional optimized fatigue time history load components. At this time, each fatigue time history load component can be corrected to obtain an optimized fatigue time history load component, and the calculation is simple. Step S2 of this embodiment includes correcting multiple fatigue time history load components according to the structural stiffness of multiple positions to obtain multiple corrected optimized fatigue time history load components. Step S4 includes loading the optimized fatigue time history load components on the shaft model and obtaining the fatigue damage value of the shaft model through finite element simulation. The fatigue damage value of the shaft model is the sum of the fatigue damage value components of the shaft model. In some embodiments, finite element software can be used for fatigue damage calculation, and thus the fatigue damage method of the application further includes dividing the shaft model into finite element grids to obtain the finite element grids.

[0063] Since the frequency of the fatigue time sequence load is high, in order to reduce the calculation amount of the finite element analysis, the mesh division does not have to be in accordance with the frequency of the fatigue time sequence load, and can be appropriately reduced, but is convenient for calculation. The finite element mesh on the main shaft can be divided in an axial symmetry and in an integer proportional relationship with the frequency of the fatigue time sequence load. In some embodiments, the frequency is divided into 1200, 5400 and 1800, and the mesh of the shaft body model can be divided into 120 in the circumferential direction. At this time, if the first reference position and the second reference position are both in the first mesh of the finite element mesh, the second mesh adjacent to the first mesh is determined as a new second reference position, and the new second reference position is used in the subsequent steps. The first mesh is any mesh of the finite element mesh, and the second mesh is adjacent to the first mesh in the circumferential direction of the main shaft. After the meshing of the finite element, the test stress is simulated in accordance with the mesh of the finite element, the test stress in each mesh is the same structure stiffness, and when the second reference position and the first reference position fall in the same mesh, the second reference position is determined as the next adjacent mesh. In this way, the fatigue damage prediction method of the application can be used more easily when the fatigue time sequence load with a faster frequency is applied to the shaft body, and the finite element analysis of the fatigue damage prediction method improves the calculation efficiency.

[0064] The fatigue damage prediction method of the application establishes a shaft body model for the shaft body, analyzes the stiffness of different positions of the shaft body model, corrects the fatigue time sequence load, and eliminates the influence of the bearing seat on the structure stiffness of the shaft body during modeling. Please refer to Figure 4 , the fatigue damage obtained by using the corrected optimal fatigue time sequence load is uniform along the circumferential direction of the shaft body, which is consistent with the actual situation that the shaft body is uniformly worn due to continuous rotation during operation, and the fatigue damage prediction method of the application has high accuracy.

[0065] The embodiments of the application also provide a fatigue damage prediction system 200 which can be applied to a wind driven generator. Figure 5 The fatigue damage prediction system 200 of an embodiment of the application is a schematic block diagram. As Figure 5 shown, the fatigue damage prediction system 200 can include one or more processors 201 for implementing the fatigue damage prediction method described in any of the above embodiments. In some embodiments, the fatigue damage prediction system 200 can include a computer readable storage medium 202 which can store programs that can be called by the processor 201, and can include a non-volatile storage medium. In some embodiments, the fatigue damage prediction system 200 can include a memory 203 and an interface 204. In some embodiments, the fatigue damage prediction system 200 of the embodiments of the application can also include other hardware according to actual application.

[0066] The fatigue damage prediction system 200 of the embodiments of the present application has similar beneficial technical effects to the fatigue damage prediction method described above, and thus will not be described again here.

[0067] The embodiments of the present application also provide a computer readable storage medium. The computer readable storage medium stores a program, and the program is executed by a processor to implement the fatigue damage prediction method described in any of the above embodiments.

[0068] The embodiments of the present application can be in the form of a computer program product implemented on one or more storage media (including but not limited to a disk storage, a CD-ROM, an optical storage, etc.) containing program codes. The computer readable storage medium includes permanent and non-permanent, removable and non-removable media, and can be implemented by any method or technology to store information. The information can be computer readable instructions, data structures, program modules or other data. Examples of computer readable storage media include, but are not limited to: new memory such as phase change memory / resistive memory / magnetic memory / ferroelectric memory (PRAM / RRAM / MRAM / FeRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape disk storage or other magnetic storage device, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0069] The fatigue damage prediction method and system thereof and computer readable storage medium provided by the embodiments of the present application are described in detail above. The fatigue damage prediction method and system thereof and computer readable storage medium of the embodiments of the present application are described by applying specific examples in this paper. The above description of the embodiments is only used to help understand the core idea of the present application, and does not limit the present application. It should be pointed out that, for those skilled in the art, without departing from the spirit and principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications should also fall within the protection scope of the appended claims of the present application.

Claims

1. A method for predicting fatigue damage of a shaft, characterized in that, The fatigue damage prediction method includes: A shaft model is established, and fatigue time-series loads are determined; the fatigue time-series loads are applied by rotation around the central axis of the shaft model, including fatigue loads at multiple times. Obtain the structural stiffness at multiple locations of the shaft model; The fatigue time-series load is corrected based on the structural stiffness at the multiple locations to obtain the corrected optimized fatigue time-series load; wherein, a correction coefficient is determined based on the structural stiffness at the multiple locations; wherein, a first reference position is determined based on the azimuth angle of the fatigue load at the current moment; and the correction coefficient of the fatigue load at the current moment is determined based on the structural stiffness of the first reference position. The fatigue time-series load is corrected according to the correction coefficient to obtain the optimized fatigue time-series load; wherein, the fatigue load at the current time is corrected according to the correction coefficient of the fatigue load at the current time to obtain the optimized fatigue load at the current time after correction, and the optimized fatigue time-series load includes optimized fatigue loads at multiple times; and The optimized fatigue time-series load is applied to the shaft model, and the fatigue damage value of the shaft model is predicted through finite element simulation.

2. The fatigue damage prediction method as described in claim 1, characterized in that, Determining the correction factor for the fatigue load at the current moment based on the structural stiffness at the first reference position includes: The second reference position is determined based on the azimuth angle of the fatigue load at the next moment from the current moment; The correction factor for the fatigue load at the current moment is determined based on the structural stiffness of the first reference position and the second reference position.

3. The fatigue damage prediction method as described in claim 2, characterized in that, The process of obtaining the structural stiffness at multiple locations of the shaft model includes: A test load is applied to the shaft model to obtain the test stress at the multiple locations on the shaft model; Determining the correction factor for the fatigue load at the current moment based on the structural stiffness at the first reference position and the second reference position includes: The correction factor for the fatigue load at the current moment is determined based on the test stress at the first reference position and the second reference position.

4. The fatigue damage prediction method as described in claim 3, characterized in that, Determining the correction factor for the fatigue load at the current moment based on the test stress at the first reference position and the second reference position includes: The ratio of the test stress at the second reference position to that at the first reference position is determined as the correction factor for the fatigue load at the current moment.

5. The fatigue damage prediction method as described in claim 2, characterized in that, The fatigue damage prediction method further includes: The shaft model is meshed using the finite element method to obtain the finite element mesh; Determining the second reference position based on the azimuth angle of the fatigue load at the next time step, based on the current time step, includes: If both the first reference position and the second reference position are within the first cell of the finite element mesh, the second cell adjacent to the first cell will be determined as the new second reference position; Determining the correction factor for the fatigue load at the current moment based on the structural stiffness at the first reference position and the second reference position includes: The correction factor for the fatigue load at the current moment is determined based on the structural stiffness of the first reference position and the new second reference position.

6. The fatigue damage prediction method as described in claim 1, characterized in that, The process of obtaining the structural stiffness at multiple locations of the shaft model includes: A test load is applied to the shaft model to obtain the test stress at the multiple locations on the shaft model; Based on the test stresses at the multiple locations, the structural stiffness at multiple locations of the shaft model is determined.

7. The fatigue damage prediction method as described in claim 1, characterized in that, The fatigue time-series load includes fatigue time-series load components in multiple directions, and the optimized fatigue time-series load includes optimized fatigue time-series load components in multiple directions. The step of correcting the fatigue time-series load based on the structural stiffness at the multiple locations to obtain the corrected optimized fatigue time-series load includes: Based on the structural stiffness at the multiple locations, the multiple fatigue time-series load components are corrected to obtain the corrected multiple optimized fatigue time-series load components. The process of applying the optimized fatigue time-series load to the shaft model and predicting the fatigue damage value of the shaft model through finite element simulation includes: The optimized fatigue time-series load components are applied to the shaft model, and the fatigue damage value components of the shaft model are predicted through finite element simulation. The fatigue damage value of the shaft model is the sum of the fatigue damage value components of the shaft model.

8. A fatigue damage prediction system, characterized in that: It includes one or more processors for implementing the fatigue damage prediction method as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, It stores a program that, when executed by a processor, implements the fatigue damage prediction method as described in any one of claims 1-7.

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