Method and device for testing bolts of a wind turbine generator system

Abstract

This application relates to the field of nondestructive testing technology, and in particular to a method and apparatus for testing bolts in wind turbine generator sets. The method includes: calculating the shear stress and axial stress of the bolt based on ultrasonic echo signals; calculating the crack depth and remaining fatigue life of the bolt based on ultrasonic echo signals; and obtaining the bolt's test results based on the shear stress, axial stress, crack depth, and remaining fatigue life. This solves the problems in related technologies, such as the single dimension of ultrasonic testing, the inability to achieve integrated monitoring of stress and structural defects, the difficulty in quantifying crack depth and assessing remaining fatigue life; and the data processing not being coupled with temperature and load interference, resulting in easily affected accuracy, lack of graded early warning, and low overall reliability, failing to meet the long-term, high-reliability monitoring requirements of high-strength bolts in wind power systems.

Description

Technical Field

[0001] This application relates to the field of nondestructive testing technology, and in particular to a method and apparatus for testing bolts of wind turbine generator sets. Background Technology

[0002] Bolts are key load-bearing connectors in wind power equipment, and their service stress state and structural crack damage directly affect the overall operational safety and service life of the turbine. Among related technologies, ultrasonic non-destructive testing has become the mainstream technology for detecting the preload and structural condition of wind turbine bolts due to its adaptability to complex working conditions. Its core principle is based on the phenomenon of acoustoelasticity, that is, utilizing the characteristic that the propagation speed of sound waves in an elastic medium changes with the internal stress of the medium to achieve basic detection of bolt stress. In specific applications, single-element ultrasonic probes or patch-type sensing structures are often used to detect a single parameter (such as stress or defect) of the bolt by exciting a single mode of ultrasonic waves.

[0003] However, the relevant technologies have a single detection dimension, which cannot achieve integrated and simultaneous monitoring of stress and structural defects, making it difficult to accurately quantify crack depth and assess the remaining fatigue life of bolts. At the same time, the data processing is not coupled with the influence of temperature and load interference, and the detection accuracy is easily affected by the service environment. Furthermore, there is a lack of a graded intelligent early warning mechanism, resulting in low reliability of the comprehensive service status evaluation of bolts. This makes it difficult to meet the long-term and high-reliability safety monitoring requirements of high-strength bolts for wind power, and improvements are urgently needed. Summary of the Invention

[0004] This application provides a method and apparatus for detecting bolts in wind turbine generator sets, in order to solve the problems in related technologies, such as ultrasonic testing having a single dimension, being unable to achieve integrated monitoring of stress and structural defects, being difficult to quantify crack depth and assess remaining fatigue life; and data processing not being coupled with temperature and load interference, making accuracy easily affected, lacking graded early warning, having low overall evaluation reliability, and failing to meet the long-term, high-reliability monitoring requirements of high-strength bolts in wind power.

[0005] The first aspect of this application provides a method for detecting bolts in a wind turbine generator set. The bolt integrates a composite wafer narrow pulse sensing module, which includes at least one central sensor and at least three edge sensors uniformly distributed along the circumference of the bolt. These sensors are used to transmit ultrasonic signals to the bolt body and receive ultrasonic echo signals propagated through the bolt body. The method includes the following steps: calculating the shear stress and axial stress of the bolt based on the ultrasonic echo signals; calculating the crack depth and remaining fatigue life of the bolt based on the ultrasonic echo signals; and obtaining the detection result of the bolt based on the shear stress, the axial stress, the crack depth, and the remaining fatigue life.

[0006] The above technical solution allows for the calculation of bolt shear stress and axial stress based on ultrasonic echo signals. The received ultrasonic echo signals can also be used to calculate the bolt crack depth and remaining fatigue life. Based on the calculated shear stress, axial stress, crack depth, and remaining fatigue life, bolt inspection results are generated. By independently calculating bolt shear stress and axial mechanical parameters using ultrasonic echo signals, and accurately characterizing crack depth and remaining fatigue life using ultrasonic echo signals, the comprehensive inspection results are analyzed using multi-dimensional key indicators. This achieves integrated and simultaneous monitoring of stress mechanics testing and structural damage life assessment, significantly improving the comprehensiveness and reliability of bolt service condition inspection and meeting the full-condition safety monitoring requirements for high-strength bolts in wind power applications.

[0007] Optionally, in one embodiment of this application, calculating the crack depth and remaining fatigue life of the bolt based on the ultrasonic echo signal includes: acquiring the amplitude characteristics of the ultrasonic echo signal; determining the defect echo amplitude and bottom wave amplitude corresponding to the bolt based on the amplitude characteristics; acquiring the propagation speed of the ultrasonic echo signal in the bolt body; calculating the crack depth of the bolt based on the defect echo amplitude, the bottom wave amplitude, and the propagation speed, and calculating the remaining fatigue life based on the crack depth.

[0008] The above technical solution allows for the analysis of ultrasonic echo signals to extract amplitude features. Based on these features, the amplitude of the defect echo and the amplitude of the backwave corresponding to the bolt are determined. The propagation velocity of the ultrasonic echo signal within the bolt body is also obtained. By comprehensively utilizing the defect echo amplitude, the backwave amplitude, and the propagation velocity, the crack depth of the bolt is calculated. Based on the crack depth, the remaining fatigue life of the bolt is further estimated. By fusing echo amplitude features to distinguish between defect echoes and backwave amplitudes, and combining ultrasonic propagation velocity to collaboratively solve for crack depth and extrapolate remaining fatigue life, the multi-feature joint calculation effectively improves the accuracy of crack depth quantification and the reliability of remaining fatigue life assessment.

[0009] Optionally, in one embodiment of this application, calculating the axial stress of the bolt based on the ultrasonic echo signal includes: acquiring the ultrasonic longitudinal wave in the ultrasonic echo signal at the first propagation sound when the bolt is in a stress-free state and at the second propagation sound when the bolt is in a stress-free state; acquiring the current temperature and a preset reference temperature of the bolt, and calculating the temperature difference between the current temperature and the preset reference temperature; and calculating the axial stress based on the temperature difference, the first propagation sound time, and the second propagation sound time.

[0010] The above technical solution can obtain the propagation time of the ultrasonic longitudinal wave in the bolt under stress-free conditions (denoted as the first propagation time) and under stress conditions (denoted as the second propagation time), respectively. It can also obtain the current temperature value and the preset reference temperature of the bolt, and then calculate the temperature difference between the current temperature and the preset reference temperature. Based on the temperature difference, the first propagation time and the second propagation time, the corresponding axial stress can be calculated. By obtaining the different propagation times of the ultrasonic longitudinal wave under stress-free and stress conditions and combining them with the temperature difference for compensation and correction, the axial stress can be calculated, eliminating temperature environment interference and effectively improving the accuracy and stability of bolt axial stress detection.

[0011] Optionally, in one embodiment of this application, the step of calculating the shear stress of the bolt based on the ultrasonic echo signal includes: calculating the acoustic time difference between the ultrasonic echo signals of the center sensor and each edge sensor; obtaining the distribution characteristics of the acoustic time difference along the circumference of the bolt, and constructing a corresponding distribution function based on the distribution characteristics; determining the direction of action of the shear stress based on the distribution function, and calculating the shear stress according to the direction of action and the amplitude of the acoustic time difference.

[0012] The above technical solution allows for the calculation of the acoustic time difference between the ultrasonic echo signals from the central sensor and each edge sensor, and the acquisition of the distribution characteristics of the acoustic time difference along the bolt circumference. A corresponding distribution function is then constructed, and based on this function, the direction of shear stress is accurately determined. Combining the determined direction of action with the amplitude of the acoustic time difference, the corresponding shear stress is calculated. By utilizing the acoustic time difference between the central sensor and the uniformly distributed edge sensors, and combining the circumferential distribution characteristics to construct a distribution function, the direction of shear stress is accurately determined. Furthermore, the amplitude of the acoustic time difference is used to quantitatively solve for the shear stress, achieving accurate identification and numerical calculation of bolt shear stress location, thus improving the comprehensiveness and accuracy of shear stress detection.

[0013] Optionally, in one embodiment of this application, determining the direction of the shear stress based on the distribution function includes: obtaining peak characteristic information of the distribution function; and determining the direction of action based on the peak characteristic information.

[0014] The above technical solution can determine the corresponding peak feature information based on the distribution function, and then determine the direction of shear stress based on the peak feature information. By extracting the peak feature information of the distribution function, the direction of shear stress can be accurately located. The feature recognition is high and the judgment logic is simple and intuitive, which effectively improves the accuracy and efficiency of bolt shear stress direction identification.

[0015] Optionally, in one embodiment of this application, the formula for calculating the axial stress may be, but is not limited to, the following: , in, This refers to the axial stress in the bolt. For longitudinal wave stress coefficient, When the bolt is in a stress-free state, the first propagating sound is... When the bolt is under stress, it is the second propagating sound. This is the temperature compensation coefficient. This is the temperature difference between the current temperature and the preset reference temperature.

[0016] The above technical solution can calculate the corresponding bolt axial stress by using acoustic time difference and temperature compensation. By introducing the relative change in longitudinal wave propagation time under stress-free and stress-state conditions, and superimposing correction terms for temperature difference and temperature compensation coefficient, the interference of ambient temperature fluctuations on the measurement results can be effectively eliminated while retaining the basic principle of acoustic elastic stress detection, thus significantly improving the accuracy and stability of bolt axial stress detection.

[0017] A second aspect of this application provides a detection device for bolts in a wind turbine generator set. The bolt integrates a composite wafer narrow pulse sensing module. The composite wafer narrow pulse sensing module includes at least one central sensor and at least three edge sensors uniformly distributed along the circumference of the bolt. It is used to emit ultrasonic signals to the bolt body and receive ultrasonic echo signals propagated through the bolt body. The device includes: a first calculation module for calculating the shear stress and axial stress of the bolt based on the ultrasonic echo signals; a second calculation module for calculating the crack depth and remaining fatigue life of the bolt based on the ultrasonic echo signals; and a generation module for obtaining the detection result of the bolt based on the shear stress, the axial stress, the crack depth, and the remaining fatigue life.

[0018] The above technical solution allows for the calculation of bolt shear stress and axial stress based on ultrasonic echo signals. The received ultrasonic echo signals can also be used to calculate the bolt crack depth and remaining fatigue life. Based on the calculated shear stress, axial stress, crack depth, and remaining fatigue life, bolt inspection results are generated. By independently calculating bolt shear stress and axial mechanical parameters using ultrasonic echo signals, and accurately characterizing crack depth and remaining fatigue life using ultrasonic echo signals, the comprehensive inspection results are analyzed using multi-dimensional key indicators. This achieves integrated and simultaneous monitoring of stress mechanics testing and structural damage life assessment, significantly improving the comprehensiveness and reliability of bolt service condition inspection and meeting the full-condition safety monitoring requirements for high-strength bolts in wind power applications.

[0019] Optionally, in one embodiment of this application, the second calculation module includes: a first acquisition unit, configured to acquire the amplitude characteristics of the ultrasonic echo signal; a determination unit, configured to determine the defect echo amplitude and bottom wave amplitude corresponding to the bolt based on the amplitude characteristics; a second acquisition unit, configured to acquire the propagation speed of the ultrasonic echo signal in the bolt body; and a first calculation unit, configured to calculate the crack depth of the bolt based on the defect echo amplitude, the bottom wave amplitude, and the propagation speed, and calculate the remaining fatigue life based on the crack depth.

[0020] The above technical solution allows for the analysis of ultrasonic echo signals to extract amplitude features. Based on these features, the amplitude of the defect echo and the amplitude of the backwave corresponding to the bolt are determined. The propagation velocity of the ultrasonic echo signal within the bolt body is also obtained. By comprehensively utilizing the defect echo amplitude, the backwave amplitude, and the propagation velocity, the crack depth of the bolt is calculated. Based on the crack depth, the remaining fatigue life of the bolt is further estimated. By fusing echo amplitude features to distinguish between defect echoes and backwave amplitudes, and combining ultrasonic propagation velocity to collaboratively solve for crack depth and extrapolate remaining fatigue life, the multi-feature joint calculation effectively improves the accuracy of crack depth quantification and the reliability of remaining fatigue life assessment.

[0021] Optionally, in one embodiment of this application, the first calculation module includes: a third acquisition unit, configured to acquire the ultrasonic longitudinal wave in the ultrasonic echo signal when the bolt is in a stress-free state for the first propagation sound and when it is in a stress state for the second propagation sound; a second calculation unit, configured to acquire the current temperature and a preset reference temperature of the bolt, and calculate the temperature difference between the current temperature and the preset reference temperature; and a third calculation unit, configured to calculate the axial stress based on the temperature difference, the first propagation sound time, and the second propagation sound time.

[0022] The above technical solution can obtain the propagation time of the ultrasonic longitudinal wave in the bolt under stress-free conditions (denoted as the first propagation time) and under stress conditions (denoted as the second propagation time), respectively. It can also obtain the current temperature value and the preset reference temperature of the bolt, and then calculate the temperature difference between the current temperature and the preset reference temperature. Based on the temperature difference, the first propagation time and the second propagation time, the corresponding axial stress can be calculated. By obtaining the different propagation times of the ultrasonic longitudinal wave under stress-free and stress conditions and combining them with the temperature difference for compensation and correction, the axial stress can be calculated, eliminating temperature environment interference and effectively improving the accuracy and stability of bolt axial stress detection.

[0023] Optionally, in one embodiment of this application, the first calculation module includes: a fourth calculation unit, used to calculate the acoustic time difference between the ultrasonic echo signals of the center sensor and each edge sensor; a construction unit, used to obtain the distribution characteristics of the acoustic time difference along the circumferential direction of the bolt, and construct a corresponding distribution function based on the distribution characteristics; and a fifth calculation unit, used to determine the direction of action of the shear stress based on the distribution function, and calculate the shear stress according to the direction of action and the amplitude of the acoustic time difference.

[0024] The above technical solution allows for the calculation of the acoustic time difference between the ultrasonic echo signals from the central sensor and each edge sensor, and the acquisition of the distribution characteristics of the acoustic time difference along the bolt circumference. A corresponding distribution function is then constructed, and based on this function, the direction of shear stress is accurately determined. Combining the determined direction of action with the amplitude of the acoustic time difference, the corresponding shear stress is calculated. By utilizing the acoustic time difference between the central sensor and the uniformly distributed edge sensors, and combining the circumferential distribution characteristics to construct a distribution function, the direction of shear stress is accurately determined. Furthermore, the amplitude of the acoustic time difference is used to quantitatively solve for the shear stress, achieving accurate identification and numerical calculation of bolt shear stress location, thus improving the comprehensiveness and accuracy of shear stress detection.

[0025] Optionally, in one embodiment of this application, the fifth calculation unit includes: an acquisition subunit for acquiring peak characteristic information of the distribution function; and a determination subunit for determining the direction of action based on the peak characteristic information.

[0026] The above technical solution can determine the corresponding peak feature information based on the distribution function, and then determine the direction of shear stress based on the peak feature information. By extracting the peak feature information of the distribution function, the direction of shear stress can be accurately located. The feature recognition is high and the judgment logic is simple and intuitive, which effectively improves the accuracy and efficiency of bolt shear stress direction identification.

[0027] Optionally, in one embodiment of this application, the formula for calculating the axial stress may be, but is not limited to, the following: , in, This refers to the axial stress in the bolt. For longitudinal wave stress coefficient, When the bolt is in a stress-free state, the first propagating sound is... When the bolt is under stress, it is the second propagating sound. This is the temperature compensation coefficient. This is the temperature difference between the current temperature and the preset reference temperature.

[0028] The above technical solution can calculate the corresponding bolt axial stress by using acoustic time difference and temperature compensation. By introducing the relative change in longitudinal wave propagation time under stress-free and stress-state conditions, and superimposing correction terms for temperature difference and temperature compensation coefficient, the interference of ambient temperature fluctuations on the measurement results can be effectively eliminated while retaining the basic principle of acoustic elastic stress detection, thus significantly improving the accuracy and stability of bolt axial stress detection.

[0029] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method for detecting bolts of a wind turbine generator set as described in the above embodiments.

[0030] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for detecting bolts in a wind turbine generator set.

[0031] A fifth aspect of this application provides a computer program product, including a computer program that, when executed, implements the above-described method for detecting bolts in a wind turbine generator set.

[0032] This application's embodiments can calculate the shear stress and axial stress of bolts based on ultrasonic echo signals, and use the received ultrasonic echo signals to calculate the crack depth and remaining fatigue life of the bolts. Then, based on the calculated shear stress, axial stress, crack depth, and remaining fatigue life, the bolt's inspection results are generated. It independently calculates the bolt's shear stress and axial mechanical parameters using ultrasonic echo signals, and accurately characterizes crack depth and remaining fatigue life using ultrasonic echo signals. The multi-dimensional key indicators are integrated to comprehensively evaluate the inspection results, achieving integrated and simultaneous monitoring of stress mechanics testing and structural damage life assessment. This significantly improves the comprehensiveness and reliability of bolt service status inspection, meeting the full-condition safety monitoring requirements of high-strength bolts in wind power. Therefore, it solves the problems in related technologies, such as the single dimension of ultrasonic testing, the inability to achieve integrated monitoring of stress and structural defects, the difficulty in quantifying crack depth and assessing remaining fatigue life; and the data processing not being coupled with temperature and load interference, making accuracy easily affected, lacking graded early warning, and having low overall evaluation reliability, failing to meet the long-term, high-reliability monitoring requirements of high-strength bolts in wind power.

[0033] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0034] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a block diagram of the overall architecture of an integrated monitoring system for stress and defects of high-strength bolts in a wind turbine generator set according to an embodiment of this application. Figure 2 This is a schematic diagram of the cross-sectional structure of a vacuum sputtering sensor according to an embodiment of this application; Figure 3 This is a schematic diagram illustrating the array sensor arrangement and shear stress detection principle according to an embodiment of this application; Figure 4 This is a flowchart illustrating a method for detecting bolts in a wind turbine generator set according to an embodiment of this application. Figure 5 This is a schematic diagram of an exponential function fitted according to an embodiment of this application; Figure 6 This is a schematic diagram of the crack depth versus remaining lifetime curve according to one embodiment of this application; Figure 7 This is a block diagram of a device for detecting bolts of a wind turbine generator set according to an embodiment of this application; Figure 8 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0035] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0036] Before introducing the detection method for wind turbine generator bolts provided in the embodiments of this application, we will first introduce an integrated monitoring system for stress and defects of high-strength bolts of wind turbine generators involved in the embodiments of this application.

[0037] Specifically, Figure 1 This is a block diagram illustrating the overall architecture of an integrated monitoring system for stress and defects of high-strength bolts in wind turbine generators according to an embodiment of this application.

[0038] like Figure 1 As shown, the system includes a composite chip narrow pulse sensing module 101, a data acquisition and transmission module 102, an edge computing processing module 103, and a remote monitoring platform 104.

[0039] The composite chip narrow pulse sensing module 101 includes an integrated sensor, a dedicated probe, and a temperature compensation unit.

[0040] The integrated sensor consists of a central sensor and six edge sensors, which are prepared by vacuum sputtering and bonded to the end face of the bolt body 105 to form the bolt to be tested.

[0041] For example, the structure of the cross-section of the vacuum sputtering sensor in this embodiment is as follows: Figure 2 As shown in the figure, the core unit of the sensor, as shown in the lower left corner, includes a PZT micropillar array 201, a silver electrode 202, and an epoxy resin adhesive 204.

[0042] Among them, the PZT (Lead Zirconate Titanate) micropillar array 201, as a piezoelectric functional layer, can realize electroacoustic and acoustic-electric conversion by utilizing the piezoelectric effect, and emit or receive ultrasonic waves.

[0043] Silver electrode 202, as an electrode layer, can provide an electrical signal transmission path for PZT.

[0044] Epoxy resin 204, as an encapsulation layer, can fix the PZT micropillar array 201, improving structural stability and insulation.

[0045] The overall structure of the sensor is shown in the upper left corner, mainly consisting of a metal electrode 206 and a piezoelectric thin film 207.

[0046] Among them, the metal electrode 206, as the external electrode layer, can cooperate with the silver electrode 202 to form a complete piezoelectric drive signal acquisition circuit.

[0047] The piezoelectric film 207 can be regarded as a higher-level description of the PZT micropillar array 201, and is the core functional layer of ultrasonic transduction.

[0048] In addition, the silicone resin curing layer 203, as an encapsulation layer for the integrated sensor and the bolt body head, can achieve a firm fit between the integrated sensor and the bolt body and optimize ultrasonic coupling.

[0049] The bolt body 205, as the object to be tested, is the target component for ultrasonic testing, and is combined with the integrated sensor to form the bolt to be tested.

[0050] In this embodiment, the PZT micropillar array 201, silver electrode 202, and epoxy resin adhesive 204 constitute the sensor body and are fixed to the bolt body 105. During detection, the sensor emits ultrasonic waves that are transmitted to the bolt body 105. The ultrasonic waves are reflected internally by the bolt body 105 and then received by the sensor again, resulting in an ultrasonic echo signal. The ultrasonic echo signal contains information about the axial load, transverse load, and defects experienced by the bolt under test, which is then analyzed and processed by the edge computing processing module 103. It should be noted that the bolts under test in this embodiment all adopt the above-described structure. Specific configurations can be made by those skilled in the art based on actual conditions, and this application does not impose any specific limitations.

[0051] For example, in this embodiment of the application, PZT material is laser-cut into a square columnar structure to form a PZT micropillar array 201. After curing with epoxy resin 204, a 10–50 μm silver electrode 202 is deposited by radio frequency magnetron sputtering. A 0.1–0.5 mm alumina ceramic protective layer is bonded to the surface of the silver electrode 202. Finally, epoxy resin 204 is bonded to the end face of the bolt body 105 to form an organosilicon resin cured layer 203, thus obtaining the corresponding tested bolt.

[0052] Furthermore, in this embodiment, the central sensor emits ultrasonic longitudinal waves to detect axial stress; based on the acoustic time difference between the central sensor and the edge sensors, the correspondence between the lateral load and the acoustic time difference is fitted, thereby calculating the corresponding lateral load. For example, this embodiment uses... Figure 3 For example, by arranging multiple sensors (such as center sensor 0 and edge sensors 1-6) along the edge of the bolt surface, it is convenient to analyze the transverse load on the bolt being tested. The transverse load has typical distribution characteristics. For instance, when the transverse load direction is from edge sensor 1 to edge sensor 4, the acoustic time corresponding to edge sensor 1 is the shortest, while the acoustic time corresponding to edge sensor 4 is the longest. Based on this characteristic, the transverse load direction can be determined, and the magnitude of the axial force can be determined by combining the detection signal from center sensor 0. Furthermore, by combining the sinusoidal distribution characteristics of the acoustic time difference of edge sensors 1-6, the direction of shear stress can be determined by fitting the vertex of a sine function, thus realizing shear stress monitoring.

[0053] A dedicated probe is connected to the monitoring host via a signal cable to ensure stable transmission of ultrasound signals.

[0054] Temperature compensation unit collects data in real time. An ambient temperature range of 40℃ to 85℃ is used for compensation and correction of stress measurements under different temperature conditions. The specific temperature value can be set by those skilled in the art according to the actual situation, and this application does not impose any specific restrictions.

[0055] The data acquisition and transmission module 102 includes a 16-channel signal acquisition unit and a LoRa (Long Range) / WiFi (Wireless Fidelity) dual-mode communication unit.

[0056] The data acquisition unit has a built-in 16-bit AD (Analog to Digital) converter with a sampling rate of no less than 100kSps, which can realize the synchronous acquisition of ultrasonic longitudinal wave signals, shear wave signals and temperature signals.

[0057] The communication unit is compatible with a three-level transmission link from the wind turbine hub to the nacelle to the central control room, with an effective transmission distance of not less than 1000m.

[0058] The edge computing processing module 103 is equipped with a multi-parameter fusion algorithm model, including a stress calculation unit, a defect identification unit, and a lifespan warning unit.

[0059] The stress calculation unit is based on the principle of acoustoelasticity and uses the axial stress calculation formula to calculate the corresponding bolt axial stress. The axial stress calculation formula will be detailed below and will not be repeated here.

[0060] In addition, the stress calculation unit can also calculate the corresponding shear stress based on the relationship between the transverse load and the acoustic time difference obtained by fitting the acoustic time difference between the center sensor and the edge sensor.

[0061] The defect identification unit can extract the characteristics of the ultrasonic echo signal of the crack through wavelet transform based on defect monitoring data collected from bolts with cracks of different depths, and combine this with the crack depth calculation formula to achieve quantitative calculation of the crack depth. The crack depth calculation formula will be detailed below and will not be repeated here.

[0062] The lifespan early warning unit can use the crack depth detected in real time as the initial crack length. Combining the Paris fatigue crack propagation formula and the stress intensity factor calculation formula, it calculates the number of load cycles required for the crack to propagate from the initial crack length to the predicted crack depth (e.g., 3 mm, which is not specifically limited in this application) through integration or numerical iteration methods. Then, by combining this with the actual load spectrum of the unit, it calculates the remaining fatigue life when the predicted crack propagates to the critical depth of 3 mm. The stress intensity factor correction factor is set to 1.1, and its specific value can be set by those skilled in the art according to actual conditions; this application does not impose specific limitations. The Paris fatigue crack propagation formula and the stress intensity factor calculation formula will be detailed below and will not be repeated here.

[0063] The remote monitoring platform 104 includes a data storage server, a visualization interface, and a hierarchical early warning module, supporting bolt positioning, display of axial stress and shear stress curves, tracking of crack depth change trends, and three-level early warning push.

[0064] The three-level early warning system is divided into three levels: general early warning, moderate early warning, and high early warning. A general early warning corresponds to a crack depth of 1–2 mm; a moderate early warning corresponds to a crack depth of 2–3 mm; and a high early warning corresponds to a crack depth of ≥3 mm.

[0065] The following describes a method and apparatus for detecting bolts in wind turbine generator sets according to embodiments of this application, with reference to the accompanying drawings. Addressing the issues mentioned in the background art, such as the single dimension of ultrasonic testing, the inability to achieve integrated monitoring of stress and structural defects, difficulty in quantifying crack depth and assessing remaining fatigue life, and the lack of coupled temperature and load interference in data processing leading to susceptibility to accuracy issues, the absence of graded early warning systems, and low overall reliability in comprehensive evaluation, thus failing to meet the long-term, high-reliability monitoring requirements for high-strength bolts in wind power, this application provides a method for detecting bolts in wind turbine generator sets. In this method, the shear stress and axial stress of the bolt can be calculated based on ultrasonic echo signals, and the crack depth and remaining fatigue life of the bolt can be calculated using the received ultrasonic echo signals. Based on the calculated shear stress, axial stress, crack depth, and remaining fatigue life, the bolt detection results are generated. The method independently calculates the bolt shear stress and axial mechanical parameters using ultrasonic echo signals, accurately characterizes crack depth and remaining fatigue life using ultrasonic echo signals, and integrates and evaluates the comprehensive detection results using multi-dimensional key indicators. This achieves integrated and simultaneous monitoring of stress mechanics testing and structural damage life assessment, significantly improving the comprehensiveness and reliability of bolt service status detection and meeting the full-condition safety monitoring requirements for high-strength bolts in wind power. This solves the problems in related technologies, such as the single dimension of ultrasonic testing, the inability to achieve integrated monitoring of stress and structural defects, the difficulty in quantifying crack depth and assessing remaining fatigue life, the lack of coupling of temperature and load interference in data processing, the susceptibility of accuracy to being affected, the lack of graded early warning, the low reliability of comprehensive evaluation, and the inability to meet the long-term high-reliability monitoring requirements of high-strength bolts in wind power.

[0066] Specifically, Figure 4 This is a flowchart of a method for detecting bolts in a wind turbine generator set according to an embodiment of this application.

[0067] like Figure 4 As shown, the method for detecting bolts in a wind turbine generator set integrates a composite crystal narrow pulse sensing module into the bolt. The composite crystal narrow pulse sensing module includes at least one central sensor and at least three edge sensors evenly distributed along the circumference of the bolt. It is used to transmit ultrasonic signals to the bolt body and receive ultrasonic echo signals propagated through the bolt body. The method for detecting bolts in a wind turbine generator set includes the following steps: In step S401, the shear stress and axial stress of the bolt are calculated based on the ultrasonic echo signal.

[0068] As one possible approach, embodiments of this application can calculate the shear stress and axial stress corresponding to the bolt based on the ultrasonic echo signal.

[0069] For example, in this application embodiment, two wind turbine bolts from the same batch to be monitored are taken as samples, and the load and temperature parameters are calibrated using a universal testing machine and a temperature control chamber.

[0070] Among them, the load calibration can be carried out in the 0-500kN loading range, with 50kN intervals, recording the acoustic time change, and fitting the acoustic time difference curve of the longitudinal wave stress coefficient and shear stress. Temperature calibration can be performed in the range of 25-60℃, with 5℃ intervals, to correct the temperature compensation coefficient and establish a coupling model between temperature and sound speed.

[0071] Furthermore, embodiments of this application can fabricate the sensor by sputtering the wind turbine bolt to be monitored, thus constructing the bolt to be tested. Specifically, in conjunction with... Figure 1 As shown, in this embodiment, the polished PZT piezoelectric preform is placed in a vacuum chamber, and a silver electrode is prepared using radio frequency magnetron sputtering technology. After electrode preparation, an alumina protective layer is bonded to two planes using welding adhesive. The ceramic sheet thickness is 0.1-0.5 mm. Acrylic welding adhesive is used for bonding, and it is cured at room temperature for 30-60 minutes to improve the surface wear resistance and impact resistance of the sensor. After preparation, the composite wafer sensor is bonded to the wind turbine bolt using epoxy resin adhesive to obtain a narrow pulse stress sensor for monitoring the stress / defect of wind turbine bolts. 5-7 sensors are arranged on each tested bolt, with one sensor located at the center of the bolt end face and the rest symmetrically arranged on the bolt edge. Four sensors are monitored at intervals for hub bolts, forming an array monitoring network covering the axial and shear stress sensitive areas.

[0072] Furthermore, in this embodiment, the data acquisition and transmission module can be controlled to trigger the sensors to acquire data at a cycle of 1-5 minutes. Specifically, stress data acquisition involves the central sensor element emitting a 5-10MHz ultrasonic longitudinal wave and receiving the reflected echo from the bolt rod to obtain the second propagation acoustic time; the edge sensor element array emits a 3-8MHz longitudinal wave to acquire the acoustic time difference between sensors in different directions, thereby identifying the magnitude and direction of the shear force; and this data is then calculated and superimposed onto the central sensor for unified output. Defect data is obtained by the central sensor element emitting a 2-5MHz ultrasonic longitudinal wave and receiving the crack reflection signal. It should be noted that all signals in this embodiment are digitized and transmitted to the edge computing processing module after 16-bit AD conversion.

[0073] Optionally, in one embodiment of this application, calculating the axial stress of the bolt based on the ultrasonic echo signal includes: acquiring the first propagation sound of the ultrasonic longitudinal wave in the ultrasonic echo signal when the bolt is in a stress-free state and the second propagation sound when the bolt is in a stress state; acquiring the current temperature and a preset reference temperature of the bolt, and calculating the temperature difference between the current temperature and the preset reference temperature; and calculating the axial stress based on the temperature difference, the first propagation sound time, and the second propagation sound time. The formula for calculating the axial stress may be, but is not limited to, the following: , in, This refers to the axial stress in the bolt. For longitudinal wave stress coefficient, When the bolt is in a stress-free state, the first propagating sound is... When the bolt is under stress, it is the second propagating sound. This is the temperature compensation coefficient. This is the temperature difference between the current temperature and the preset reference temperature.

[0074] In some embodiments, this application can extract the first propagation time of the ultrasonic longitudinal wave in the ultrasonic echo signal when the bolt is in a stress-free state, and the second propagation time when the bolt is in a stress state, respectively. The current temperature of the bolt is acquired in real time, and then, based on a preset reference temperature, the difference between the current temperature and the preset reference temperature is calculated. Taking into account the temperature difference, the first propagation time, and the second propagation time, the axial stress of the bolt is calculated. The formula for calculating the axial stress can be, but is not limited to, the following: , in, This refers to the axial stress in the bolt. For longitudinal wave stress coefficient, When the bolt is in a stress-free state, the first propagating sound is... When the bolt is under stress, it is the second propagating sound. This is the temperature compensation coefficient. This is the temperature difference between the current temperature and the preset reference temperature.

[0075] For example, in this application embodiment, the axial stress corresponding to the bolt can be calculated using the axial stress calculation formula based on the stress calculation unit in the edge computing processing module.

[0076] Optionally, in one embodiment of this application, the shear stress of the bolt is calculated based on the ultrasonic echo signal, including: calculating the acoustic time difference between the ultrasonic echo signals of the center sensor and each edge sensor; obtaining the distribution characteristics of the acoustic time difference along the circumference of the bolt, and constructing a corresponding distribution function based on the distribution characteristics; determining the direction of the shear stress based on the distribution function, and calculating the shear stress according to the direction of action and the amplitude of the acoustic time difference.

[0077] It is understood that, in the embodiments of this application, the distribution function can be understood as a continuous or discrete distribution law constructed by mathematically fitting the acoustic time-lapse data at different circumferential angles of the bolt. Specifically, in the embodiments of this application, ultrasonic echo signals at different circumferential angles of the bolt can be collected by a central sensor and edge sensors, the acoustic time-lapse at each angle can be calculated, and the distribution function can be fitted with the circumferential angle as the independent variable and the acoustic time-lapse amplitude as the dependent variable. For example, the acoustic time-lapse between each edge sensor and the central sensor can be fitted with the bolt circumferential angle as the abscissa and the acoustic time-lapse as the ordinate using a sine function or a polynomial to obtain the distribution function.

[0078] In some embodiments, the present application embodiments may first calculate the acoustic time difference between the ultrasonic echo signals of the center sensor and each edge sensor, and obtain the distribution characteristics of the acoustic time difference in the circumferential direction of the bolt. Then, based on the distribution characteristics, a corresponding distribution function is constructed to determine the direction of shear stress. Combined with the amplitude of the acoustic time difference, the corresponding shear stress is calculated.

[0079] For example, in combination Figure 1 As shown, in this embodiment of the application, the central sensor in the composite wafer narrow pulse sensing module can emit ultrasonic longitudinal waves to detect axial stress, and calculate the acoustic time difference between the edge sensors and the central sensor. Based on the sinusoidal distribution of the acoustic time difference fed back by each sensor, the corresponding sinusoidal distribution function is fitted, and the peak value of the sinusoidal distribution function is obtained. The location of the peak value is the direction of the shear stress.

[0080] Furthermore, through experiments, embodiments of this application have shown that the acoustic time difference between the direction indicated by shear stress (i.e., lateral load) and the acoustic time of the central sensor exhibits an exponential function, such as... Figure 5 As shown, therefore, in this embodiment of the application, the time difference between the peak value and the acoustic time of the center sensor can be substituted into the corresponding exponential function to determine the magnitude of the corresponding shear stress. The expression of the exponential function can be, but is not limited to, as follows: , in, The magnitude of the shear force, The maximum sound time fitted is the time difference between the sound time of the central sensor and the maximum sound time.

[0081] It should be noted that the embodiments of this application can fit different exponential functions for different bolt sizes. That is, the determination of the exponential function can be understood as a calibration work. The specific settings can be made by those skilled in the art according to the actual situation. This application does not impose any specific limitations.

[0082] Optionally, in one embodiment of this application, determining the direction of shear stress based on the distribution function includes: obtaining peak characteristic information of the distribution function; and determining the direction of action based on the peak characteristic information.

[0083] It is understood that, in the embodiments of this application, the peak characteristic information can be understood as the set of all characteristic parameters corresponding to the extreme points (such as peak points, valley points, etc., which are not specifically limited in this application) in the distribution function curve. It is the most representative core feature in the distribution function and the key basis for inferring the direction of shear stress.

[0084] In actual implementation, the embodiments of this application can extract the peak characteristic information of the distribution function and accurately determine the direction of shear stress based on the peak characteristic information.

[0085] In step S402, the crack depth and remaining fatigue life of the bolt are calculated based on the ultrasonic echo signal.

[0086] In some embodiments, the present application can calculate the corresponding crack depth and remaining fatigue life based on the ultrasonic echo signal.

[0087] Optionally, in one embodiment of this application, calculating the crack depth and remaining fatigue life of a bolt based on an ultrasonic echo signal includes: acquiring the amplitude characteristics of the ultrasonic echo signal; determining the defect echo amplitude and bottom wave amplitude corresponding to the bolt based on the amplitude characteristics; acquiring the propagation velocity of the ultrasonic echo signal in the bolt body; calculating the crack depth of the bolt based on the defect echo amplitude, bottom wave amplitude, and propagation velocity, and calculating the remaining fatigue life based on the crack depth.

[0088] In some embodiments, the present application can perform amplitude characteristic analysis on the ultrasonic echo signal to determine the corresponding defect echo amplitude and bottom wave amplitude, and at the same time obtain the propagation speed of the ultrasonic wave in the bolt body. Then, based on the defect echo amplitude, bottom wave amplitude and propagation speed, the crack depth of the bolt is calculated, and the remaining fatigue life of the bolt is determined based on the crack depth.

[0089] For example, in combination Figure 1As shown, this embodiment of the application can utilize a defect identification unit to monitor bolts with cracks of different depths to obtain corresponding defect monitoring data. Wavelet transform is then used to extract crack amplitude features, and the corresponding crack depth is obtained by combining this with the crack depth calculation formula. The crack depth calculation formula can be, but is not limited to, expressed as: , in, The crack depth. The calibration coefficient is determined based on crack monitoring data of different bolts sampled on-site. For the defect echo amplitude, The amplitude of the bottom wave. The speed of sound.

[0090] Furthermore, in this embodiment of the application, a life warning unit is used to predict the remaining fatigue life when the crack extends to a critical depth of 3 mm, based on the Paris fatigue crack propagation formula and the stress intensity factor calculation formula, combined with the crack depth obtained by real-time detection.

[0091] The expression for the Paris fatigue crack propagation formula can be, but is not limited to, as follows: , in, The crack depth. For the number of load cycles, These are empirical constants for materials. For the range of stress intensity factors, This is a material experience index.

[0092] The formula for calculating the stress intensity factor can be, but is not limited to, expressed as: , in, As a correction factor, the specific method described in this application is determined experimentally and can be selected. The specific settings can be made by those skilled in the art according to the actual situation, and this application does not impose specific restrictions.

[0093] like Figure 6 As shown in the embodiments of this application, different crack depths have different effects on the remaining fatigue life, but there are other influencing factors, such as different bolt sizes and load conditions. This application does not impose specific limitations. Figure 6 The black spot is for an M39×536mm bolt made of 42CrMoA material, with an axial stress measurement range of 450kN, a crack depth of 1.2mm, and a predicted remaining fatigue life of 1.09 years.

[0094] In step S403, the bolt inspection results are obtained based on shear stress, axial stress, crack depth, and remaining fatigue life.

[0095] As one possible approach, embodiments of this application can obtain bolt testing results based on shear stress, axial stress, crack depth, and remaining fatigue life.

[0096] It should be noted that, in the embodiments of this application, the axial / shear stress measurement values ​​are corrected by combining the temperature compensation coefficient, the axial stress error is ≤±2.5%, and the shear stress identification accuracy is ≤±5%; the defect echo amplitude and flight time are extracted by wavelet denoising, and the crack depth is calculated, with a crack depth identification accuracy of ≤0.1m; the crack depth and real-time stress value are substituted into the Paris fatigue crack propagation formula to predict the remaining fatigue life, and a high-altitude warning is triggered when the remaining fatigue life is ≤36 days.

[0097] Furthermore, in this application embodiment, the early warning can be divided into three levels based on the crack depth: general warning: crack depth 1-2mm; moderate warning: crack depth 2-3mm; high warning: crack depth ≥3mm.

[0098] In addition, in this embodiment of the application, shear stress, axial stress, crack depth, remaining fatigue life and test results can be uploaded to a remote monitoring platform through an edge computing processing module. The remote monitoring platform pushes early warning information through audible and visual alarms and SMS notifications, and stores historical data for trend analysis.

[0099] The following describes the method for detecting bolts in wind turbine generator sets proposed in this application, using a specific embodiment as an example.

[0100] Example 1: This application embodiment is applied to the monitoring of blade root bolts (M39×536mm, 42CrMoA material) of a 2.3MW wind turbine in a wind farm in Ningxia Hui Autonomous Region. Eight bolts are monitored. The sensor is a vacuum sputtering type, with a PZT column cross-section size of 15mm. The silver electrode is 20 μm thick, and the aluminum oxide protective layer is 0.3 mm thick.

[0101] The data acquisition and transmission module is deployed inside the wheel hub, powered by 24V DC, with an acquisition cycle of 2 minutes per acquisition, and communicates with the cabin router via LoRa.

[0102] The edge computing processing module sets the longitudinal wave stress coefficient to 0.2313, the temperature compensation coefficient to 17.0355, and the crack depth calibration coefficient to 0.85; the edge computing processing module optimizes the shear stress algorithm, combined with... Figure 3As shown, the transverse load curve is fitted based on the acoustic time difference of edge sensors 1, 4, and center sensor 0, and the corresponding shear stress, axial stress, crack depth, and remaining fatigue life are then obtained. The axial stress measurement range is 430-460 kN, the shear stress identification accuracy is ±4.8%, two 1.2 mm deep cracks were successfully identified, the remaining fatigue life is predicted to be 1.09 years, and the early warning accuracy is 100%.

[0103] The method for detecting bolts in wind turbine generators proposed in this application can calculate the shear stress and axial stress of the bolts based on ultrasonic echo signals. It also uses the received ultrasonic echo signals to calculate the crack depth and remaining fatigue life of the bolts. Based on the calculated shear stress, axial stress, crack depth, and remaining fatigue life, the method generates bolt detection results. It independently calculates the bolt shear stress and axial mechanical parameters using ultrasonic echo signals, accurately characterizes the crack depth and remaining fatigue life using ultrasonic echo signals, and integrates and evaluates the comprehensive detection results using multi-dimensional key indicators. This achieves integrated and simultaneous monitoring of stress mechanics detection and structural damage life assessment, significantly improving the comprehensiveness and reliability of bolt service condition detection and meeting the full-condition safety monitoring requirements of high-strength bolts in wind power. This solves the problems in related technologies, such as the single dimension of ultrasonic detection, the inability to achieve integrated monitoring of stress and structural defects, the difficulty in quantifying crack depth and assessing remaining fatigue life, the lack of coupling with temperature and load interference in data processing leading to easily affected accuracy, the lack of graded early warning, and low reliability of comprehensive evaluation, failing to meet the long-term, high-reliability monitoring requirements of high-strength bolts in wind power.

[0104] Next, referring to the accompanying drawings, a device for detecting bolts of a wind turbine generator set according to an embodiment of this application is described.

[0105] Figure 7 This is a block diagram of a device for detecting bolts in a wind turbine generator set according to an embodiment of this application.

[0106] like Figure 7 As shown, the detection device 10 for the bolts of the wind turbine generator set integrates a composite crystal narrow pulse sensing module into the bolt. The composite crystal narrow pulse sensing module includes at least one central sensor and at least three edge sensors evenly distributed along the circumference of the bolt, which are used to transmit ultrasonic signals to the bolt body and receive ultrasonic echo signals after propagation through the bolt body. The detection device 10 for the bolts of the wind turbine generator set includes a first calculation module 701, a second calculation module 702 and a generation module 703.

[0107] The first calculation module 701 is used to calculate the shear stress and axial stress of the bolt based on the ultrasonic echo signal.

[0108] The second calculation module 702 is used to calculate the crack depth and remaining fatigue life of the bolt based on the ultrasonic echo signal.

[0109] The generation module 703 is used to obtain the inspection results of the bolts based on shear stress, axial stress, crack depth and remaining fatigue life.

[0110] Optionally, in one embodiment of this application, the second calculation module 702 includes: a first acquisition unit, a determination unit, a second acquisition unit, and a first calculation unit.

[0111] The first acquisition unit is used to acquire the amplitude characteristics of the ultrasonic echo signal.

[0112] The determination unit is used to determine the defect echo amplitude and bottom echo amplitude corresponding to the bolt based on the amplitude characteristics.

[0113] The second acquisition unit is used to acquire the propagation speed of the ultrasonic echo signal in the bolt body.

[0114] The first calculation unit is used to calculate the crack depth of the bolt based on the defect echo amplitude, the bottom wave amplitude, and the propagation speed of the sound, and to calculate the remaining fatigue life based on the crack depth.

[0115] Optionally, in one embodiment of this application, the first calculation module 701 includes: a third acquisition unit, a second calculation unit, and a third calculation unit.

[0116] The third acquisition unit is used to acquire the first propagation sound of the ultrasonic longitudinal wave in the ultrasonic echo signal when the bolt is in a stress-free state and the second propagation sound when the bolt is in a stress state.

[0117] The second calculation unit is used to obtain the current temperature and preset reference temperature of the bolt, and to calculate the temperature difference between the current temperature and the preset reference temperature.

[0118] The third calculation unit is used to calculate the axial stress based on the temperature difference, the first propagation time, and the second propagation time.

[0119] Optionally, in one embodiment of this application, the first computing module 701 includes: a fourth computing unit, a construction unit, and a fifth computing unit.

[0120] The fourth calculation unit is used to calculate the acoustic time difference between the ultrasonic echo signals of the central sensor and each edge sensor.

[0121] The construction unit is used to obtain the distribution characteristics of the acoustic time difference along the circumference of the bolt, and to construct the corresponding distribution function based on the distribution characteristics.

[0122] The fifth calculation unit is used to determine the direction of shear stress based on the distribution function, and to calculate the shear stress according to the direction of action and the amplitude of the acoustic time difference.

[0123] Optionally, in one embodiment of this application, the fifth calculation unit includes: an acquisition subunit and a determination subunit.

[0124] Among them, the acquisition sub-unit is used to obtain the peak characteristic information of the distribution function.

[0125] The sub-unit is determined to determine the direction of action based on peak characteristic information.

[0126] Optionally, in one embodiment of this application, the formula for calculating axial stress may be, but is not limited to, the following: , in, This refers to the axial stress in the bolt. For longitudinal wave stress coefficient, When the bolt is in a stress-free state, the first propagating sound is... When the bolt is under stress, it is the second propagating sound. This is the temperature compensation coefficient. This is the temperature difference between the current temperature and the preset reference temperature.

[0127] It should be noted that the explanation of the above-described embodiment of the method for detecting bolts of wind turbine generator sets also applies to the detection device for bolts of wind turbine generator sets in this embodiment, and will not be repeated here.

[0128] The wind turbine bolt detection device proposed in this application can calculate the shear stress and axial stress of the bolt based on ultrasonic echo signals, and calculate the crack depth and remaining fatigue life of the bolt using the received ultrasonic echo signals. Based on the calculated shear stress, axial stress, crack depth, and remaining fatigue life, the device generates bolt detection results. It independently calculates the bolt shear stress and axial mechanical parameters using ultrasonic echo signals, accurately characterizes the crack depth and remaining fatigue life using ultrasonic echo signals, and integrates and evaluates the comprehensive detection results using multi-dimensional key indicators. This achieves integrated and simultaneous monitoring of stress mechanics detection and structural damage life assessment, significantly improving the comprehensiveness and reliability of bolt service status detection and meeting the full-condition safety monitoring requirements of high-strength wind turbine bolts. Therefore, it solves the problems in related technologies, such as the single dimension of ultrasonic detection, the inability to achieve integrated monitoring of stress and structural defects, the difficulty in quantifying crack depth and assessing remaining fatigue life, the lack of coupling with temperature and load interference in data processing leading to easily affected accuracy, the lack of graded early warning, and low overall evaluation reliability, failing to meet the long-term, high-reliability monitoring requirements of high-strength wind turbine bolts.

[0129] Figure 8 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. The electronic device may include: The memory 801, the processor 802, and the computer program stored on the memory 801 and capable of running on the processor 802.

[0130] When the processor 802 executes the program, it implements the method for detecting bolts of wind turbine generator sets provided in the above embodiments.

[0131] Furthermore, electronic devices also include: Communication interface 803 is used for communication between memory 801 and processor 802.

[0132] The memory 801 is used to store computer programs that can run on the processor 802.

[0133] The memory 801 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0134] If the memory 801, processor 802, and communication interface 803 are implemented independently, then the communication interface 803, memory 801, and processor 802 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized into address buses, data buses, control buses, etc. For ease of representation, Figure 8 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0135] Optionally, in a specific implementation, if the memory 801, processor 802, and communication interface 803 are integrated on a single chip, then the memory 801, processor 802, and communication interface 803 can communicate with each other through an internal interface.

[0136] The processor 802 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0137] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for detecting bolts in a wind turbine generator set.

[0138] This application also provides a computer program product, including a computer program that, when executed, implements the above-described method for detecting bolts on wind turbine generator sets.

[0139] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0140] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0141] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0142] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). In addition, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically by optically scanning paper or other media, then editing, interpreting or otherwise processing them as necessary, and then storing them in computer memory.

[0143] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0144] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0145] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0146] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method of inspecting a bolt of a wind turbine generator system, characterized by, The bolt integrates a composite crystal narrow pulse sensing module, which includes at least one central sensor and at least three edge sensors evenly distributed along the circumference of the bolt. The module is used to transmit ultrasonic signals to the bolt body and receive ultrasonic echo signals propagated through the bolt body. The method includes the following steps: Based on the ultrasonic echo signal, the shear stress and axial stress of the bolt are calculated; Based on the ultrasonic echo signal, the crack depth and remaining fatigue life of the bolt are calculated. The test results of the bolt are obtained based on the shear stress, the axial stress, the crack depth, and the remaining fatigue life.

2. The method of claim 1, wherein, The calculation of the crack depth and remaining fatigue life of the bolt based on the ultrasonic echo signal includes: Obtain the amplitude characteristics of the ultrasonic echo signal; Based on the amplitude characteristics, the defect echo amplitude and bottom echo amplitude corresponding to the bolt are determined; The propagation speed of the ultrasonic echo signal in the bolt body is obtained; Based on the defect echo amplitude, the bottom wave amplitude, and the propagation speed, the crack depth of the bolt is calculated, and based on the crack depth, the remaining fatigue life is calculated.

3. The method of claim 1, wherein, The calculation of the axial stress of the bolt based on the ultrasonic echo signal includes: The ultrasonic longitudinal wave in the ultrasonic echo signal is obtained when the bolt is in a stress-free state and when it is in a stress state, respectively, during the first propagation sound of the ultrasonic longitudinal wave; Obtain the current temperature and preset reference temperature of the bolt, and calculate the temperature difference between the current temperature and the preset reference temperature; The axial stress is calculated based on the temperature difference, the first propagation time, and the second propagation time.

4. The method of claim 1, wherein, The calculation of the shear stress of the bolt based on the ultrasonic echo signal includes: Calculate the acoustic time difference between the ultrasonic echo signals of the central sensor and each edge sensor; The distribution characteristics of the acoustic time difference along the bolt circumference are obtained, and a corresponding distribution function is constructed based on the distribution characteristics; The direction of the shear stress is determined based on the distribution function, and the shear stress is calculated based on the direction of action and the amplitude of the acoustic time difference.

5. The method of claim 4, wherein, Determining the direction of the shear stress based on the distribution function includes: Obtain the peak characteristic information of the distribution function; The direction of action is determined based on the peak characteristic information.

6. The method of claim 1, wherein, The formula for calculating the axial stress is: ， wherein, is the axial stress in the bolt, is the longitudinal wave stress coefficient, is the first propagation sound time of the bolt in the stress-free state, is the second propagation sound time of the bolt in the stressed state, is the temperature compensation coefficient, is the temperature difference between the current temperature and the preset reference temperature.

7. A testing device for bolts in a wind turbine generator set, characterized in that, The bolt integrates a composite crystal narrow pulse sensing module, which includes at least one central sensor and at least three edge sensors evenly distributed along the circumference of the bolt. The module is used to transmit ultrasonic signals to the bolt body and receive ultrasonic echo signals propagated through the bolt body. The device includes: The first calculation module is used to calculate the shear stress and axial stress of the bolt based on the ultrasonic echo signal. The second calculation module is used to calculate the crack depth and remaining fatigue life of the bolt based on the ultrasonic echo signal. The generation module is used to obtain the test results of the bolt based on the shear stress, the axial stress, the crack depth, and the remaining fatigue life.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the method for detecting bolts of a wind turbine generator as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the method for detecting bolts of a wind turbine generator as described in any one of claims 1-6.

10. A computer program product, characterized in that, Includes a computer program, which, when executed, is used to implement the method for detecting wind turbine generator bolts as described in any one of claims 1-6.

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