Blade fatigue damage prevention and control method, system, medium and product based on online monitoring

Abstract

The application discloses a kind of blade fatigue damage prevention and control control method, system, medium and product based on online monitoring, it is related to mechanical component state monitoring and life management field, the method comprises: the vibration signal of blade is collected in real time;Based on blade 3D model, surface pressure field of blade under different working conditions is calculated using CFD software, and steady-state steam flow force load of blade under different working conditions is obtained;Based on this, the vibration stress response of blade under working condition is simulated and analyzed using finite element method to obtain high-cycle stress amplitude;Based on high-cycle stress amplitude, the single damage of blade under working condition is calculated, and the total cumulative damage of blade under all working conditions is calculated;According to total cumulative damage and multistage early warning threshold, the current early warning level and current control measure of blade are determined;According to current control measure, blade is controlled.The application improves the safety and work efficiency of the whole unit, prolongs the service life.

Description

Technical Field

[0001] This application relates to the field of mechanical component condition monitoring and life management, and in particular to a method, system, medium, and product for preventing and controlling blade fatigue damage based on online monitoring. Background Technology

[0002] Blades are the core components of a steam turbine, and their health directly affects the safety, efficiency, and lifespan of the entire unit. During operation, blades are subjected to complex alternating loads for extended periods, making them highly susceptible to high-cycle fatigue (HCF) damage. HCF is one of the main failure modes leading to blade fracture, and once it occurs, the consequences are often catastrophic. Currently, the management of blade fatigue damage mainly relies on: 1. Regular maintenance: Non-destructive testing of blades during downtime. This method is time-sensitive, and maintenance cycles are set based on experience; both conservative and aggressive strategies can easily lead to a waste of human and material resources. 2. Model-based life prediction: Conservative lifespan of blades is estimated using load simulations and material fatigue performance data from the design phase. This method cannot reflect individual differences and load fluctuations in real-world operating environments, resulting in limited prediction accuracy. 3. Simple vibration monitoring: Monitoring the overall vibration level of the unit using sensors. This method cannot accurately assess the damage state of blades, and the early warning is not targeted enough.

[0003] Currently, relevant monitoring methods lack real-time, online, and quantitative assessment of blade fatigue damage, as well as closed-loop linkage between assessment results and operation and maintenance decisions. When anomalies are detected, the system can usually only be passively shut down for inspection, without providing proactive and actionable control recommendations to slow damage development or optimize maintenance plans. This severely reduces the safety and efficiency of the entire unit and shortens its service life. Summary of the Invention

[0004] The purpose of this application is to provide a method, system, medium, and product for preventing and controlling blade fatigue damage based on online monitoring. It can determine corresponding prevention and control measures according to the current warning level of the blade, and proactively provide prevention and control suggestions for the blade, thereby improving the safety and working efficiency of the entire unit and extending its service life.

[0005] To achieve the above objectives, this application provides the following solution: Firstly, this application provides a method for preventing and controlling leaf fatigue damage based on online monitoring, including: Real-time acquisition of blade vibration signals; A 3D model of the blade was constructed, and based on the 3D model of the blade, the surface pressure field of the blade under different operating conditions was calculated using CFD software to obtain the steady-state steam flow force load of the blade under different operating conditions. For any operating condition, based on the steady-state gas flow force load and vibration signal, the finite element method is used to simulate and analyze the vibration stress response of the blade under the operating condition to obtain the high-cycle stress amplitude. The single-cycle damage of the blade under the aforementioned operating condition is calculated based on the high-cycle stress amplitude. The total cumulative damage is obtained by summing up the single damage of the blade under all operating conditions using Miner's linear cumulative damage rule. The current warning level and current control measures for the blade are determined based on the total cumulative damage and multi-level warning thresholds. The blades are controlled according to the current prevention and control measures.

[0006] Secondly, this application provides a blade fatigue damage prevention and control system based on online monitoring, comprising: The data acquisition module is used to collect the vibration signals of the blades in real time. The steady-state airflow force load calculation module is used to construct a 3D model of the blade and, based on the 3D model of the blade, use CFD software to calculate the surface pressure field of the blade under different operating conditions, thereby obtaining the steady-state airflow force load of the blade under different operating conditions. The high-cycle stress amplitude determination module is used to simulate and analyze the vibration stress response of the blade under any working condition based on the steady-state steam flow force load and vibration signal, and obtain the high-cycle stress amplitude. A single-damage calculation module is used to calculate the single-damage of the blade under the operating condition based on the high-cycle stress amplitude. The total cumulative damage calculation module is used to accumulate the single damage of the blade under all operating conditions using the Miner linear cumulative damage rule to obtain the total cumulative damage. The early warning level determination module is used to determine the current early warning level and current control measures for the blade based on the total cumulative damage and multi-level early warning thresholds. The control module is used to control the blades according to the current prevention and control measures.

[0007] Thirdly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the blade fatigue damage prevention and control method based on online monitoring as described above.

[0008] Fourthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the blade fatigue damage prevention and control method based on online monitoring as described above.

[0009] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a blade fatigue damage prevention and control method, system, medium, and product based on online monitoring. By real-time acquisition of blade vibration signals, for any operating condition, the vibration stress response of the blade under that condition is analyzed based on steady-state steam flow load and vibration signals to obtain the corresponding high-cycle stress amplitude. Based on this, the single-time damage of the blade under that operating condition is calculated, realizing real-time monitoring of the blade. The Miner linear cumulative damage rule is used to accumulate the single-time damage of the blade under all operating conditions to obtain the total cumulative damage of the blade during the entire working period, realizing a quantitative assessment of blade damage. Based on the total cumulative damage, the current warning level and current prevention and control measures are determined, realizing a closed-loop linkage between the assessment results and operation and maintenance decisions, providing proactive prevention and control measures for the blade, improving the safety and working efficiency of the entire unit, and extending its service life. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is an application environment diagram of a blade fatigue damage prevention and control method based on online monitoring in one embodiment of this application.

[0012] Figure 2 This is a flowchart illustrating a method for preventing and controlling blade fatigue damage based on online monitoring, provided as an embodiment of this application.

[0013] Figure 3 This is a detailed flowchart illustrating a method for preventing and controlling blade fatigue damage based on online monitoring, provided in one embodiment of this application. Detailed Implementation

[0014] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0015] To make the objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0016] The blade fatigue damage prevention and control method based on online monitoring provided in this application can be applied to, for example... Figure 1 In the application environment shown, terminal 101 communicates with server 102 via a network. A data storage system can store the data that server 102 needs to process. The data storage system can be set up independently, integrated into server 102, or placed in the cloud or on another server. Terminal 101 can send the blade vibration signal to server 102. Server 102 receives the blade vibration signal, constructs a 3D model of the blade, and based on the 3D model, uses CFD software to calculate the surface pressure field of the blade under different operating conditions, obtaining the steady-state airflow force load of the blade under different operating conditions. For any operating condition, based on the steady-state airflow force load and vibration signal, the finite element method is used to simulate and analyze the vibration stress response of the blade under that operating condition, obtaining the high-cycle stress amplitude. Based on the high-cycle stress amplitude, the single-time damage of the blade under that operating condition is calculated. The Miner linear cumulative damage rule is used to accumulate the single-time damage of the blade under all operating conditions to obtain the total cumulative damage. Based on the total cumulative damage and multi-level early warning thresholds, the current early warning level and current control measures of the blade are determined. The blade is controlled according to the current control measures. Server 102 can feed back the current warning level and current prevention and control measures to terminal 101.

[0017] Among them, terminal 101 can be, but is not limited to, various desktop computers, laptops and tablets, etc., and server 102 can be implemented by independent server or server cluster composed of multiple servers, or it can be cloud server.

[0018] In one exemplary embodiment, such as Figure 2 and Figure 3 As shown, a method for preventing and controlling blade fatigue damage based on online monitoring is provided. This method is executed by computer equipment, specifically by a terminal or server alone, or by both a terminal and a server. In this embodiment, the method is applied to... Figure 1 Taking server 102 as an example, the explanation includes the following steps 201 to 207. Wherein: Step 201: Real-time acquisition of blade vibration signals.

[0019] Step 202: Construct a 3D model of the blade, and based on the 3D model of the blade, use CFD software to calculate the surface pressure field of the blade under different operating conditions to obtain the steady-state gas flow force load of the blade under different operating conditions.

[0020] Step 203: For any operating condition, based on the steady-state gas flow force load and vibration signal, the finite element method is used to simulate and analyze the vibration stress response of the blade under the operating condition to obtain the high-cycle stress amplitude.

[0021] Step 204: Calculate the single-cycle damage of the blade under the operating condition based on the high-cycle stress amplitude.

[0022] Step 205: Use Miner's linear cumulative damage rule to sum up the single damage of the blade under all operating conditions to obtain the total cumulative damage.

[0023] Step 206: Determine the current warning level and current prevention and control measures for the blade based on the total cumulative damage and multi-level warning thresholds.

[0024] Step 207: Implement control measures on the blades according to the current prevention and control measures.

[0025] By implementing steps 201 to 207 above, this application can improve the safety and working efficiency of the entire unit, and also extend its service life.

[0026] In an exemplary embodiment, step 201 specifically includes installing a non-contact vibration sensor (such as an eddy current sensor, fiber optic sensor, or acoustic sensor) on the blade to be monitored or its adjacent stationary component, and monitoring and acquiring the vibration signal of the blade in real time, the vibration signal including the vibration amplitude and vibration frequency.

[0027] In an exemplary embodiment, step 202 specifically includes steps 21-22: Step 21: Construct a 3D model of the blade.

[0028] Specifically, the KSCAN20 portable 3D laser scanner was used to perform 3D scanning and mapping of the turbine blades, and Solidworks was used to perform geometric modeling of the scanning and mapping data to obtain a 3D model of the turbine blades.

[0029] Step 22: Based on the 3D model of the blade, CFD software is used to calculate the surface pressure field of the blade under different operating conditions to obtain the steady-state aerodynamic load of the blade under different operating conditions. This specifically includes steps 221-222: Step 221: For any operating condition, import the blade 3D model into CFD software and calculate the surface pressure field of the blade under the operating condition.

[0030] The 3D model of the turbine blades obtained in step 21 is imported into Computational Fluid Dynamics (CFD) software. The fluid material is set to steam, and the blade boundary conditions are set (inlet: temperature / pressure, mass flow rate, velocity, etc.; outlet: temperature / pressure, etc.). The surface pressure field of the blades under these operating conditions (cold, warm, hot, etc.) is calculated using the CFD software CFX-TurboGrid. The turbine blades participate in both rated load and low load operating conditions. For each operating condition, the above process of setting the fluid material, blade boundary conditions, and performing calculations is executed to obtain the surface pressure field of the blades under different operating conditions.

[0031] Specifically, CFX-TurboGrid is a pre-processing tool in the ANSYS CFX software suite specifically designed for fluid dynamics simulation of rotating machinery (such as pumps, fans, compressors, turbines, etc.). Its core function is to automatically generate high-quality structured meshes.

[0032] Step 222: The surface pressure field is converted into the steady-state gas flow force load of the blade using the finite element method, and the steady-state gas flow force load under different working conditions is obtained.

[0033] The pressure field on the blade surface obtained by CFD calculation was subjected to coordinate unification and mesh matching using ANSYS software. The pressure data on the flow field mesh was mapped to the surface elements of the structural finite element blade through interpolation. The normal component of pressure was extracted according to the normal direction of the surface element, and the force magnitude of each surface element was calculated based on the normal component of pressure. The force magnitude of the surface element was integrated by area to form the equivalent surface force. The equivalent surface force was then distributed to each node and transformed to obtain the force load of each node. Based on the force load of each node, the steady-state steam flow force load under different working conditions was finally obtained.

[0034] In an exemplary embodiment, step 203 specifically includes steps 31-39: Step 31: Based on the 3D model of the blade, the stress response of the blade under the combined action of the preset centrifugal force and the steady-state airflow load is simulated and analyzed using the finite element method to obtain the static stress distribution cloud map of the blade.

[0035] The 3D model of the blade was loaded using the finite element software ABAQUS. The material parameters of the blade (such as material grade, elastic modulus, Poisson's ratio, density, yield strength, tensile strength, etc., obtained from reference materials) were set. Hexahedral first-order elements were used to mesh most areas such as the blade body and blade root. For local areas with complex geometry, tetrahedral second-order elements were used to improve the calculation accuracy.

[0036] To efficiently simulate the static characteristics of the entire blade, a cyclic symmetry calculation method is adopted. The cyclic symmetry calculation method is divided into the following two types: First, under the condition of ideal cyclic symmetry (with identical geometry and load), a single blade model is used to apply periodic boundary conditions; Second, if there are local connections or asymmetric features such as braces or shrouds, a sector model consisting of several blades containing such features is used to apply periodic boundary conditions, which is the method of calculating multiple blades.

[0037] In this embodiment, the blades have tension bars; therefore, several blade calculation methods are employed. Specifically, corresponding contact boundary conditions are defined between the blade root and the rotor blade root slot, and between the tension bars and adjacent tension bars, to simulate real mechanical connections and interactions. A preset centrifugal force and the steady-state gas flow force load calculated in step 22 are applied to the blades, and a static solution is performed to calculate the stress response of the blades under the combined action of the preset centrifugal force and the steady-state gas flow force load calculated by CFD, obtaining a static stress distribution cloud map of the blades.

[0038] The preset centrifugal force is obtained from the turbine speed. In actual operation, the preset centrifugal force can be applied by inputting the turbine speed and rotation direction in the corresponding module of the finite element software.

[0039] Step 32: The maximum static stress in the static stress distribution cloud map of the blade is taken as the low-cycle fatigue amplitude of the blade.

[0040] Identify the location of maximum static stress on the blade from the static stress distribution cloud map, and use the maximum static stress at the location of maximum static stress as the low-cycle fatigue amplitude of the blade. The darker the color in the static stress distribution cloud map, the greater the static stress.

[0041] Step 33: Construct a full-circle three-dimensional finite element model using finite element software; the full-circle three-dimensional finite element model includes all blades and disks.

[0042] The complete process of blade vibration stress analysis based on the finite element software ABAQUS begins with building a full-circle three-dimensional finite element model that includes all blades and the rotor.

[0043] Step 34: Based on the full-circle three-dimensional finite element model, the Lanczos iterative method is used to perform eigenvalue analysis to obtain the modal frequencies of the entire blade.

[0044] Based on the three-dimensional finite element model of the entire circle constructed in step 33, eigenvalue analysis is performed by the Lanczos iterative method to extract the mode of the entire blade. The mode of the entire blade includes the natural frequency (the calculated value of the frequency, see Table 1) and its corresponding spatial mode shape. The natural frequency is also called the modal frequency. The modal frequency determines the resonance risk, and the spatial mode shape reveals the vibration mode and energy distribution. The experimental frequency values ​​in Table 1 are the vibration frequencies of the blade collected in real time in step 201.

[0045] Table 1

[0046] Step 35: Determine the excitation modes of the entire blade circumference using modal frequencies and vibration frequencies.

[0047] After obtaining the natural frequencies and spatial mode shapes of the entire blade ring, the steady-state aerodynamic load distribution obtained in step 222 is mapped onto the blade surface as an external load input. Using the natural frequencies obtained from the modal analysis in step 34 as a reference, frequency sweep calculations are performed near each frequency to solve for the blade's displacement response and equivalent dynamic stress distribution at different excitation frequencies. By comparing the amplitude of the equivalent dynamic stress at each frequency point, when the peak amplitude of the equivalent dynamic stress appears near the first (107.9Hz) and second (226.9Hz) frequencies, and the equivalent dynamic stress is largest and the response is most significant at the first or second frequency, while there are no obvious resonance peaks in other frequency bands, the actual excitation mode of the blade can be determined as the [number]th mode. This mode is then identified as the excitation mode of the entire blade ring for subsequent fatigue assessment. In this embodiment, the final excitation mode of the entire blade ring is the second mode.

[0048] Step 36: Determine the simple harmonic excitation force based on the vibration amplitude and modal frequency.

[0049] The vibration amplitude collected in real time in step 201 is used to define the simple harmonic excitation force acting on the blade. The frequency of the simple harmonic excitation force is equal to the modal frequency obtained in step 34, and the vibration amplitude of the simple harmonic excitation force is equal to the vibration amplitude collected in real time.

[0050] Step 37: Based on the steady-state steam flow force load and harmonic excitation force, the forced response of the blade under the excitation mode is analyzed using the modal superposition method to obtain the dynamic stress distribution cloud map of the blade.

[0051] Based on the steady-state gas flow force load and harmonic excitation force, a forced response analysis is performed using the modal superposition method. Specifically, the steady-state gas flow force load calculated in step 22 is first applied as a static background, and then the harmonic excitation force defined in step 36 is applied. The analysis requires setting two key parameters: one is the damping ratio determined empirically or experimentally, which controls the amplification of the resonance peak; the other is the excitation force factor used to match the vibration magnitude.

[0052] The applied harmonic excitation force and steady-state gas flow force load are projected according to the mode shapes of each order using finite element software, and transformed into generalized forces in the modal coordinates of each order. The generalized forces are scalar forces obtained after decomposing the load according to the mode shapes, and are used as inputs to the single-degree-of-freedom equations. Then, based on the independent single-degree-of-freedom equations of each mode, the "generalized coordinate" response of each mode is obtained, which is the stress response result of each mode. Finally, the stress response results of each mode are superimposed to obtain the dynamic stress distribution cloud map of the blade at the modal frequency. In this embodiment, the second-order mode shape is selected.

[0053] Step 38: Take the maximum dynamic stress of the blade's dynamic stress distribution cloud map as the dynamic stress of the blade at the modal frequency.

[0054] Locate the position of the maximum dynamic stress in the dynamic stress distribution cloud map, and take the maximum dynamic stress corresponding to the position of the maximum dynamic stress as the dynamic stress of the blade at the modal frequency.

[0055] Step 39: Based on the low-cycle fatigue amplitude, the dynamic stress is corrected using the Goodman correction method to obtain the high-cycle stress amplitude under the standard load spectrum.

[0056] The expression for correcting the dynamic stress using the Goodman correction method is as follows: ; in, Here, represents the high-cycle stress amplitude, and represents the corrected stress. The stress amplitude of the standard fatigue load spectrum. For low-cycle fatigue amplitude, The maximum strength was obtained by consulting relevant materials.

[0057] In an exemplary embodiment, step 204 specifically includes steps 41-43: Step 41: When the high-cycle stress amplitude is less than or equal to the fatigue limit, it is determined that the blade is not damaged under the stated operating condition.

[0058] Specifically, the high-cycle stress amplitude under the standard load spectrum was compared with the fatigue limit of the material at 10^9 cycles, where the fatigue limit of the material at 10^9 cycles was obtained by consulting relevant literature.

[0059] When the high-cycle stress amplitude is less than or equal to the fatigue limit, it is determined that the blade is not damaged under the stated operating condition. In other words, the high-cycle fatigue life of the blade at the position of maximum dynamic stress is infinite, and no single-damage calculation is required. The turbine unit continues to operate normally.

[0060] Step 42: When the high-cycle stress amplitude is greater than the fatigue limit, determine the number of cycles based on the high-cycle stress amplitude and the SN curve; calculate the single damage of the blade under the operating condition based on the number of cycles.

[0061] When the high-cycle stress amplitude exceeds the fatigue limit, the number of cycles N under the high-cycle stress amplitude under the standard load spectrum is determined by the SN (Stress Number of Cycles) curve. f The SN curve was obtained by consulting relevant materials.

[0062] The formula for calculating a single injury is: D i =1 / N f , where D i This represents a single instance of blade damage under the i-th operating condition.

[0063] In one exemplary embodiment, step 205 specifically includes: Using Miner's linear cumulative damage rule, the single damage to the blade under all operating conditions is accumulated, i.e., the total cumulative damage is calculated, resulting in the total cumulative damage D = ΣD. i D represents the total cumulative damage; where, under all operating conditions, it refers to all operating conditions the blade participates in from the time of replacement to the time when the blade's vibration signal is collected in step 201.

[0064] In an exemplary embodiment, step 206 specifically includes steps 61-63: Based on the total cumulative damage D and a multi-level warning threshold, the warning thresholds are set, including a first warning threshold TH1, a second warning threshold TH2 and a third warning threshold TH3, and the first warning threshold TH1, the second warning threshold TH2 and the third warning threshold TH3 increase sequentially.

[0065] In this embodiment, the first warning threshold TH1 and the second warning threshold TH2 are determined based on power plant experience and mainly serve as warnings. The third warning threshold TH3 is the limit value for safe operation of the steam turbine and is generally set at 75%.

[0066] Step 61: When the total cumulative damage D exceeds the first warning threshold TH1 but does not exceed the second warning threshold TH2, the current warning level is determined to be a Level 1 warning.

[0067] In actual implementation, when the calculated total cumulative damage D exceeds the first warning threshold TH1 but does not exceed the second warning threshold TH2, a level one warning is triggered.

[0068] The prevention and control measures for a Level 1 warning are at the alert level, suggesting operational optimization of the unit. Therefore, when the warning level is Level 1, the current prevention and control measures are determined to be reducing the turbine unit load and shortening the time interval between two consecutive collections of blade vibration signals. Specifically: Adjusting unit load: The control system recommends that operators reduce the turbine unit load to reduce dynamic stress and delay damage accumulation.

[0069] Enhanced monitoring: Shorten the time interval between two adjacent turbine data acquisitions to conduct more intensive tracking. Data acquisition can collect data such as pressure, temperature, speed, vibration frequency and amplitude. In this embodiment, the vibration signal of the blade is collected.

[0070] Step 62: When the total cumulative damage D exceeds the second warning threshold TH2 but does not exceed the third warning threshold TH3, the current warning level is determined to be a level 2 warning. The current prevention and control measures are to arrange shutdown for maintenance and shorten the maintenance cycle. During the shutdown inspection window, the blades are inspected in detail and the damaged blades are repaired.

[0071] The prevention and control measures for a Level II warning fall under the action level, recommending maintenance intervention. Therefore, when the warning level is Level II, the current prevention and control measures are to arrange for shutdown maintenance and shorten the maintenance cycle. During the shutdown inspection window, the blades are thoroughly inspected, and damaged blades are repaired. Specifically: Scheduled maintenance: In the next scheduled shutdown window, prioritize a detailed inspection of this blade.

[0072] Advance maintenance: It is recommended to shorten the maintenance cycle and arrange for immediate or as soon as possible shutdown maintenance.

[0073] Repair and Strengthening: During maintenance, damaged blades are subjected to shot peening. High-speed shot impacts the blade surface, causing plastic deformation and introducing a residual compressive stress layer. This significantly counteracts the tensile stress under the working load, inhibiting the initiation and propagation of fatigue cracks, effectively restoring and extending the blade's fatigue life.

[0074] Step 63: When the total cumulative damage D exceeds the third warning threshold TH3, the current warning level is determined to be a level three warning. The current prevention and control measures are to perform in-situ ultrasonic testing and visual inspection of the blades without disassembly. If cracks or severe wear are found, the blades will be replaced or repaired.

[0075] The prevention and control measures for a Level 3 warning are considered emergency, and an emergency shutdown is recommended. Therefore, when the warning level is Level 3, the current prevention and control measures are to perform in-situ ultrasonic testing on the blades without disassembly and visual inspection of the reinforcing bars. If cracks or severe wear are found, replacement or repair should be carried out. Specifically: After shutdown, perform in-situ ultrasonic testing (targeting the blade root and impeller groove) and visual inspection of the reinforcing bars on the warning blades without disassembly. If cracks or severe wear are found, replacement or repair (such as laser shock peening) should be carried out.

[0076] This application has the following effects: By combining online monitoring and real-time calculation, continuous tracking of blade fatigue damage is achieved. Combined with finite element analysis and fatigue damage calculation, vibration signals are transformed into precise stress values ​​and damage levels, enabling quantitative assessment and avoiding the ambiguity of traditional vibration monitoring. This establishes a complete closed loop from "state perception" to "damage assessment" and then to "prevention and control decision-making." This application not only provides alarms for different assessment results but also offers specific and actionable control and maintenance suggestions, directly transforming data analysis results into productivity. Through load adjustment suggestions, the damage process can be proactively intervened without shutting down the machine. Through repair methods such as shot peening, damage can be effectively repaired and the blade's fatigue resistance improved, thereby significantly extending the blade's service life and reducing total life-cycle costs. This method can be widely applied to the health management of blades in various rotating machinery, possessing universal applicability and significant engineering application value.

[0077] Based on the same inventive concept, this application also provides a system for implementing the above-mentioned blade fatigue damage prevention and control method based on online monitoring. The solution provided by this system is similar to the solution described in the above method. Therefore, the specific limitations of one or more embodiments of the blade fatigue damage prevention and control system based on online monitoring provided below can be found in the limitations of the blade fatigue damage prevention and control method based on online monitoring described above, and will not be repeated here.

[0078] In one exemplary embodiment, a blade fatigue damage prevention and control system based on online monitoring is provided, comprising: The data acquisition module is used to collect the vibration signals of the blades in real time.

[0079] The steady-state gas flow force load calculation module is used to construct a 3D model of the blade and, based on the 3D model, to calculate the surface pressure field of the blade under different operating conditions using CFD software, thereby obtaining the steady-state gas flow force load of the blade under different operating conditions.

[0080] The high-cycle stress amplitude determination module is used to simulate and analyze the vibration stress response of the blade under any operating condition based on the steady-state steam flow force load and vibration signal, and obtain the high-cycle stress amplitude.

[0081] The single-cycle damage calculation module is used to calculate the single-cycle damage of the blade under the operating condition based on the high-cycle stress amplitude.

[0082] The total cumulative damage calculation module is used to accumulate the single damage of the blade under all operating conditions using Miner's linear cumulative damage rule to obtain the total cumulative damage.

[0083] The warning level determination module is used to determine the current warning level and current prevention and control measures for the blade based on the total cumulative damage and multi-level warning thresholds.

[0084] The control module is used to control the blades according to the current prevention and control measures.

[0085] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0086] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0087] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0088] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0089] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, etc., and are not limited to these.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preventing and controlling leaf fatigue damage based on online monitoring, characterized in that, include: Real-time acquisition of blade vibration signals; A 3D model of the blade was constructed, and based on the 3D model of the blade, the surface pressure field of the blade under different operating conditions was calculated using CFD software to obtain the steady-state steam flow force load of the blade under different operating conditions. For any operating condition, based on the steady-state hydrodynamic load and vibration signal, the finite element method is used to simulate and analyze the vibration stress response of the blade under the operating condition to obtain the high-cycle stress amplitude. Specifically, this includes: based on the blade 3D model, using the finite element method to simulate and analyze the stress response of the blade under the combined action of a preset centrifugal force and the steady-state hydrodynamic load to obtain a static stress distribution cloud map of the blade; taking the maximum static stress in the static stress distribution cloud map of the blade as the low-cycle fatigue amplitude of the blade; constructing a full-circle three-dimensional finite element model using finite element software; the full-circle three-dimensional finite element model includes all blades and the impeller; based on the full-circle three-dimensional finite element model, using Lanczos iteration... Eigenvalue analysis was performed using a substitution method to obtain the modal frequencies of the entire blade ring. The excitation modes of the entire blade ring were determined using the modal frequencies and vibration frequencies. The harmonic excitation force was determined based on the vibration amplitude and modal frequencies. Based on the steady-state gas flow load and harmonic excitation force, the forced response of the blade under the excitation modes was analyzed using the modal superposition method, resulting in a dynamic stress distribution cloud map of the blade. The maximum dynamic stress in the dynamic stress distribution cloud map of the blade was taken as the dynamic stress of the blade at the modal frequencies. Based on the low-cycle fatigue amplitude, the dynamic stress was corrected using the Goodman correction method to obtain the high-cycle stress amplitude under the standard load spectrum. The vibration signal includes the vibration amplitude and vibration frequency. The calculation of single-cycle damage of the blade under the operating condition based on the high-cycle stress amplitude specifically includes: if the high-cycle stress amplitude is less than or equal to the fatigue limit, the blade is determined to be undamaged under the operating condition; if the high-cycle stress amplitude is greater than the fatigue limit, the number of cycles is determined based on the high-cycle stress amplitude and the SN curve; the single-cycle damage of the blade under the operating condition is calculated based on the number of cycles, and the formula for calculating single-cycle damage is: D i =1 / N f , where D i For a single instance of blade damage under the i-th operating condition, N f This represents the number of loop iterations. The total cumulative damage is obtained by summing up the single damage of the blade under all operating conditions using Miner's linear cumulative damage rule. The current warning level and current control measures for the blade are determined based on the total cumulative damage and multi-level warning thresholds. The blades are controlled according to the current prevention and control measures.

2. The method for preventing and controlling blade fatigue damage based on online monitoring according to claim 1, characterized in that, Based on the aforementioned 3D model of the blade, CFD software was used to calculate the surface pressure field of the blade under different operating conditions, obtaining the steady-state vapor flow force load of the blade under different operating conditions, specifically including: For any operating condition, the blade 3D model is imported into CFD software and the surface pressure field of the blade under the operating condition is calculated. The surface pressure field was converted into steady-state gas flow force load on the blade using the finite element method, and the steady-state gas flow force load under different operating conditions was obtained.

3. The method for preventing and controlling blade fatigue damage based on online monitoring according to claim 1, characterized in that, The expression for correcting the dynamic stress using the Goodman correction method is as follows: ； in, For high-cycle stress amplitude, The stress amplitude of the standard fatigue load spectrum. For low-cycle fatigue amplitude, It represents the ultimate strength.

4. The method for preventing and controlling blade fatigue damage based on online monitoring according to claim 1, characterized in that, The multi-level warning thresholds include a first warning threshold, a second warning threshold, and a third warning threshold, with the first warning threshold, the second warning threshold, and the third warning threshold increasing sequentially. Specifically, the current warning level and current control measures for the blade are determined based on the total cumulative damage and multi-level warning thresholds, including: When the total cumulative damage exceeds the first warning threshold but does not exceed the second warning threshold, the current warning level is determined to be Level 1 warning; the current prevention and control measures are to reduce the turbine unit load and shorten the time interval between two adjacent collections of blade vibration signals. When the total cumulative damage exceeds the second warning threshold but does not exceed the third warning threshold, the current warning level is determined to be a level two warning. The current prevention and control measures are to arrange shutdown for maintenance and shorten the maintenance cycle. During the shutdown inspection window, the blades are inspected in detail and the damaged blades are repaired. When the total cumulative damage exceeds the third warning threshold, the current warning level is determined to be a level three warning. The current prevention and control measures are to perform in-situ ultrasonic testing and visual inspection of the blades without disassembly. If cracks or severe wear are found, the blades will be replaced or repaired.

5. A blade fatigue damage prevention and control system based on online monitoring, characterized in that, include: The data acquisition module is used to collect the vibration signals of the blades in real time. The steady-state airflow force load calculation module is used to construct a 3D model of the blade and, based on the 3D model of the blade, use CFD software to calculate the surface pressure field of the blade under different operating conditions, thereby obtaining the steady-state airflow force load of the blade under different operating conditions. The high-cycle stress amplitude determination module is used to simulate and analyze the vibration stress response of the blade under any operating condition based on the steady-state gas flow load and vibration signal using the finite element method to obtain the high-cycle stress amplitude. Specifically, it includes: simulating and analyzing the stress response of the blade under the combined action of a preset centrifugal force and the steady-state gas flow load using the finite element method based on the blade 3D model to obtain a static stress distribution cloud map of the blade; taking the maximum static stress in the static stress distribution cloud map of the blade as the low-cycle fatigue amplitude of the blade; constructing a full-circle three-dimensional finite element model using finite element software; the full-circle three-dimensional finite element model includes all blades and the impeller; based on the full-circle three-dimensional... A finite element model was used, and the Lanczos iterative method was employed for eigenvalue analysis to obtain the modal frequencies of the entire blade ring. The excitation modes of the entire blade ring were determined using the modal frequencies and vibration frequencies. The harmonic excitation force was determined based on the vibration amplitude and modal frequencies. Based on the steady-state airflow load and the harmonic excitation force, the forced response of the blade under the excitation modes was analyzed using the modal superposition method, resulting in a dynamic stress distribution cloud map of the blade. The maximum dynamic stress in the dynamic stress distribution cloud map of the blade was taken as the dynamic stress of the blade at the modal frequencies. Based on the low-cycle fatigue amplitude, the Goodman correction method was used to correct the dynamic stress, obtaining the high-cycle stress amplitude under the standard load spectrum. The single-cycle damage calculation module is used to calculate the single-cycle damage of the blade under the operating condition based on the high-cycle stress amplitude. Specifically, it includes: if the high-cycle stress amplitude is less than or equal to the fatigue limit, then the blade is determined to be undamaged under the operating condition; if the high-cycle stress amplitude is greater than the fatigue limit, then the number of cycles is determined based on the high-cycle stress amplitude and the SN curve; the single-cycle damage of the blade under the operating condition is calculated based on the number of cycles. The calculation formula for single-cycle damage is: D i =1 / N f , where D i For a single instance of blade damage under the i-th operating condition, N f This represents the number of loop iterations. The total cumulative damage calculation module is used to accumulate the single damage of the blade under all operating conditions using the Miner linear cumulative damage rule to obtain the total cumulative damage. The early warning level determination module is used to determine the current early warning level and current control measures for the blade based on the total cumulative damage and multi-level early warning thresholds. The control module is used to control the blades according to the current prevention and control measures.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the blade fatigue damage prevention and control method based on online monitoring as described in any one of claims 1-4.

7. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the blade fatigue damage prevention and control method based on online monitoring as described in any one of claims 1-4.

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