Swivel bolt pre-tightening force monitoring device and method under high temperature condition

Abstract

The invention provides a swivel bolt pre-tightening force monitoring device and method under a high temperature condition. The device comprises a magnetostriction sheet, a coil-only type EMAT detection probe, a multi-channel EMAT detection circuit and a signal processor, during monitoring, the magnetostrictive sheet is coupled with the swivel bolt, and the detection probe is placed around the swivel bolt; the detection circuit continuously introduces similar direct current into the plurality of coils of the detection probe and simultaneously introduces strong pulse current into each coil according to a preset sequence; the detection probe comprises a plurality of coils which generate a magnetic field under the action of introduced similar direct current; the magnetostrictive sheet generates telescopic vibration in a magnetic field, so that ultrasonic waves are generated on the surface of the swivel bolt; the detection probe receives an ultrasonic echo signal; and the signal processor analyzes the echo signal and extracts pre-tightening force information of the swivel bolt. According to the invention, on-line monitoring of the pre-tightening force of the swivel bolt under a high-temperature condition can be realized.

Description

Technical Field

[0001] This application belongs to the technical field of measuring the pre-tightening force of rotating bolts, and particularly relates to a monitoring device and method for the pre-tightening force of rotating bolts under high-temperature conditions. Background Art

[0002] Rotating bolt connections are a fundamental part of many structures and mechanical systems. The correct pre-tightening force ensures that rotating bolts do not loosen or break when subjected to loads, thus maintaining the safety of the entire structure. Improper pre-tightening force, whether too tight or too loose, can lead to connection failures, increasing the risk of accidents and malfunctions. In many mechanical applications, such as engine assembly and the installation of machinery and equipment, due to the lack of on-line non-destructive testing and monitoring technologies, it is impossible to accurately measure the pre-tightening force of rotating bolts, resulting in the forced shutdown of these devices and even serious accidents such as equipment cracking, gas leakage, and explosion, causing significant casualties and economic losses.

[0003] Currently, the service life of rotating bolts in many power plants and petrochemical enterprises has generally far exceeded the designed life. However, due to the difficulty in replacing rotating bolts, they need to continue operating, and the costs of large-scale replacement of high-temperature rotating bolts and the economic losses caused by production stoppages are extremely high. Therefore, it is necessary to monitor the pre-tightening force of rotating bolts in real time to give early warnings of potential rotating bolt failure risks.

[0004] Under high-temperature and high-pressure environments, the temperature of rotating bolts can exceed 550°C and they are often located in inaccessible positions, making it difficult to implement conventional detection methods. Existing detections of the pre-tightening force of rotating bolts under high-temperature conditions are mostly carried out by regular non-destructive testing and inspection during shutdowns. Due to the large scale and complex structure of high-temperature equipment, the accessibility of detection is poor, and it usually relies on manual detection, resulting in low detection efficiency and heavy tasks.

[0005] Based on this, there is an urgent need to develop a new type of monitoring device and method for the pre-tightening force of rotating bolts under high-temperature conditions. Summary of the Invention

[0006] The object of the present invention is to provide a monitoring device and method for the pre-tightening force of rotating bolts under high-temperature conditions, which can realize on-line monitoring of the pre-tightening force of rotating bolts under high-temperature conditions.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] On the one hand, the present application provides a monitoring device for the pre-tightening force of a rotating bolt under high-temperature conditions, comprising: a magnetostrictive sheet, a single-coil EMAT detection probe, a multi-channel EMAT detection circuit, and a signal processor; during monitoring, the magnetostrictive sheet is coupled with the rotating bolt, and the single-coil EMAT detection probe is placed around the rotating bolt; the single-coil EMAT detection probe, the multi-channel EMAT detection circuit, and the signal processor are connected in sequence;

[0009] The multi-channel EMAT detection circuit is configured to continuously supply a quasi-DC current to multiple coils of the single-coil EMAT detection probe and sequentially supply a strong pulsed current to each coil in a preset order, and to detect the echo signals received by each coil, perform multi-channel signal synchronization to ensure that the echo signals received by different coils are consistent in time, and at the same time compare the echo signals received by different coils to identify the pre-tightening force values in different directions or at different positions, so as to obtain more comprehensive and accurate information for detection;

[0010] The single-coil EMAT detection probe includes multiple coils, which are configured to generate a magnetic field under the action of a quasi-DC current;

[0011] The magnetostrictive sheet is configured to generate a telescopic vibration in the magnetic field, thereby generating ultrasonic waves on the surface of the rotating bolt;

[0012] The single-coil EMAT detection probe is further configured to receive the echo signals of the ultrasonic waves;

[0013] The multi-channel EMAT detection circuit is further configured to detect the echo signals received by each coil of the single-coil EMAT detection probe;

[0014] The signal processor is configured to analyze the echo signals detected by the multi-channel EMAT detection circuit and extract the pre-tightening force information of the rotating bolt.

[0015] The signal processor can perform signal demodulation, filtering, amplification, and decoding to extract the pre-tightening force information of the rotating bolt.

[0016] Each coil in the single-coil EMAT detection probe can work independently. By using multiple coils in cooperation, multiple coils perform independent detections at the same time, improving the detection efficiency and speed, enhancing the signal coverage, and realizing multi-channel detection.

[0017] Based on the detection of the echo signals received by each coil and in combination with the order of the strong pulsed currents supplied to each coil, multi-channel signal synchronization is performed to ensure that the echo signals received by different coils are consistent in time, and at the same time compare the echo signals received by different coils to identify the pre-tightening force values in different directions or at different positions, so as to obtain more comprehensive and accurate information for detection.

[0018] Furthermore, the magnetostrictive sheet is made of ferromagnetic material. A vanadium-iron intermetallic compound magnetostrictive sheet with a thickness of 0.5 mm is used. This material has detectable deformation, a melting point far exceeding 550 °C, good high-temperature resistance, can deform under the action of a magnetic field, and has a magnetostrictive coefficient as high as 2000 to 4000 ppm.

[0019] Furthermore, the coil of the single-coil EMAT detection probe is one of a racetrack coil, a spiral coil, and a butterfly coil.

[0020] Furthermore, the multi-channel EMAT detection circuit includes a trigger module, a high-voltage capacitor discharge module, a low-voltage capacitor discharge module, an impedance matching module, and an echo detection module; the trigger module, the high-voltage capacitor discharge module, and the low-voltage capacitor discharge module are electrically connected in sequence; the low-voltage capacitor discharge module, the impedance matching module, and the echo detection module are all electrically connected to the coil of the single-coil EMAT detection probe;

[0021] The trigger module and the echo detection module are electrically connected to the signal processor.

[0022] Furthermore, the multi-channel EMAT detection circuit further includes a sampling current module, and the sampling current module is electrically connected to the impedance matching module.

[0023] The sampling current module is connected to the impedance matching module through a wire. The sampling current module observes the discharge current through a sampling resistor to judge the working state of the multi-channel EMAT detection circuit and the waveform and amplitude of the discharge current.

[0024] Furthermore, the signal processor includes: a 16-bit AD high-speed analog-to-digital converter, a field programmable gate array (FPGA) processing module, and a data transmission module; the 16-bit AD high-speed analog-to-digital converter is connected to the FPGA processing module; the FPGA processing module is connected to the data transmission module;

[0025] Furthermore, the 16-bit AD high-speed analog-to-digital converter receives the analog signal from the single-coil EMAT detection probe;

[0026] Furthermore, the FPGA processing module is used to perform real-time processing on the signal according to a specific algorithm to extract the pre-tightening force information of the rotating bolt.

[0027] Among them, the real-time processing of the signal includes filtering, feature extraction, and waveform reconstruction, etc.

[0028] Furthermore, the data transmission module adopts an ESP8266 WIFI module with a heat dissipation design, which supports long-term stable operation and has high anti-interference ability; it can send the processed data to an external intelligent analysis terminal platform.

[0029] Furthermore, a heat sink is provided on the PCB of the signal processor, and a heat dissipation material with high thermal conductivity is used, which can improve its usability in high-temperature environments, enable it to work within a relatively high temperature range, and maintain a relatively low cost, thus enabling a large number of applications.

[0030] Traditional rotating bolt monitoring technology under high-temperature conditions still has the limitations of wired transmission in data transmission, with complex wiring and poor detection feasibility. The corresponding wireless transmission is still in the experimental research and development stage, with extremely high costs and difficult to achieve a large number of applications. By adopting the advanced optimization algorithm and parallel processing ability of the FPGA processing module, the present invention has achieved a significant improvement in data processing speed, effectively enhanced the data transmission efficiency, and ensured the speed and reliability of data transmission. In addition, the present invention introduces non-contact remote data transmission technology, realizes seamless connection, and significantly reduces the physical and electromagnetic interference risks of traditional contact transmission.

[0031] Furthermore, the heat sink adopts a single-wing or double-wing design to optimize air flow and reduce resistance.

[0032] Furthermore, the heat dissipation material is aluminum, which has the characteristics of low cost, easy processing, and good thermal conductivity.

[0033] Furthermore, the monitoring device further includes an intelligent analysis terminal platform. The signal processor is connected to the intelligent analysis terminal platform, and the signal processor wirelessly transmits the extracted pre-tightening force information of the rotating bolt to the intelligent analysis terminal platform.

[0034] Furthermore, the signal processor is wirelessly connected to the intelligent analysis terminal platform.

[0035] The intelligent analysis terminal platform is an integrated platform of software and hardware, which is used to receive, store, analyze, and display data, mainly including data such as pre-tightening force information of rotating bolts. Thus, the pre-tightening force of the rotating bolt under the current high-temperature conditions can be viewed remotely and online in real time, realizing functions such as automatic state collection, intelligent conversion, and visual display.

[0036] Further, the intelligent analysis terminal platform includes a data receiving module, a storage management system, a data preprocessing module, a data processing and analysis module, and a real-time image generation module; the data receiving module is connected to the storage management system, the storage management system is connected to the data preprocessing module; the data preprocessing module is connected to the data processing and analysis module; the data processing and analysis module is connected to the real-time image generation module; wherein the storage management system stores and manages the received data, including a database and a file system; the data preprocessing module performs preprocessing such as filtering and denoising on the original data; the data processing and analysis module performs algorithm processing and analysis on the preprocessed data to extract the characteristic values of the pre-tightening force of the rotating bolt under high-temperature conditions; the real-time image generation module generates an image display in real time according to the processing results;

[0037] Further, the visual display adopts intelligent monitoring technology to display the operating status and fault warning indicators of the IoT devices, including the power and power consumption of the IoT devices, the magnitude and change trend of the pre-tightening force of the rotating bolt, the historical record of the pre-tightening force of the rotating bolt over a period of time, the record of abnormal values of the pre-tightening force of the rotating bolt, the duration of the pre-tightening force of the rotating bolt, the distribution of the pre-tightening force of the rotating bolt, etc.

[0038] The process record of the pre-tightening force detection of the rotating bolt under high-temperature environment is relatively difficult. The traditional monitoring technology of the rotating bolt under high-temperature conditions has the characteristic of instantaneity in data preservation, which makes it extremely difficult to save and analyze the past and current data in real time. The lack of long-term data records makes it impossible to effectively track the historical status and trend analysis of the operating status of the rotating bolt under high-temperature conditions, thus restricting the prediction of potential problems and the formulation of preventive measures. This application designs an intelligent analysis terminal platform to monitor and analyze the actual situation and historical records of the pre-tightening force of the rotating bolt under high-temperature conditions, which is convenient for regular detection and maintenance.

[0039] On the other hand, this application provides an ultrasonic monitoring method for the pre-tightening force of a rotating bolt under high-temperature conditions, and uses the above-mentioned monitoring device to realize the ultrasonic monitoring of the pre-tightening force of the rotating bolt under high-temperature conditions.

[0040] Further, the method may include: continuously passing a quasi-direct current through multiple coils of the single-coil EMAT detection probe while sequentially passing a strong pulse current into each coil in a preset order; driving the particles on the surface of the rotating bolt to vibrate in the vertical direction and causing the magnetostrictive patch to generate strain deformation in the horizontal direction, thereby generating longitudinal waves and shear waves respectively; measuring the propagation time of the longitudinal waves and shear waves in the rotating bolt based on the echo signals, and calculating the axial length change of the rotating bolt , and then estimating the pre-tightening force according to the following formula:

[0041]

[0042]

[0043] Wherein: is the pre-tightening force of the rotating bolt, is the elastic modulus of the rotating bolt material, is the cross-sectional area of the rotating bolt, is the natural length of the rotating bolt, is the density of the rotating bolt material, is the propagation time difference between the shear wave and the longitudinal wave; λ is the propagation speed of the ultrasonic wave in the rotating bolt.

[0044] Beneficial effects:

[0045] A device and method for monitoring the pre-tightening force of a rotating bolt under high-temperature conditions provided by the present invention have the following advantages: First, the magnetostrictive probe is equipped with a new type of magnetostrictive material, which can work stably under high-temperature conditions, has high sensitivity and good response speed, and realizes the measurement of the pre-tightening force of a high-temperature rotating bolt by only receiving and transmitting signals of the coil-type EMAT detection probe; compared with traditional magnetostrictive ultrasonic sensors, it does not require an external permanent magnet or regular magnetization of the permanent magnet, has a small volume, can be detected in a narrow space, its bias magnetic field is provided by a coil passing a quasi-direct current, and the magnetic field strength will not gradually weaken over time, nor will the residual magnetic strength of the magnetostrictive patch after magnetization by the permanent magnet be demagnetized or even degaussed due to the influence of temperature and time. Second, the coil-type EMAT detection probe includes multiple coils, and each coil can work independently. By using multiple coils in cooperation, multiple coils perform independent detections at the same time, improving the detection efficiency and speed, enhancing the signal coverage, and realizing multi-channel detection. Based on the echo signals received by each coil and combined with the order of passing strong pulsed currents into each coil, multi-channel signal synchronization is performed to ensure that the echo signals received by different coils are consistent in time, and at the same time, the echo signals received by different coils are compared to identify the pre-tightening force values in different directions or positions to obtain more comprehensive and accurate information for detection. Third, while continuously passing a quasi-direct current into the multiple coils of the coil-type EMAT detection probe, strong pulsed currents are sequentially passed into each coil in a preset order; driving the particles on the surface of the rotating bolt to vibrate in the vertical direction and causing the magnetostrictive patch to generate strain deformation in the horizontal direction, thereby generating longitudinal waves and transverse waves respectively; based on the echo signals, measuring the propagation times of the longitudinal waves and transverse waves in the rotating bolt, the axial length change of the rotating bolt can be calculated very precisely, and then the pre-tightening force can be estimated according to the formula, and a high pre-tightening force measurement accuracy can be obtained; it is applicable to various materials and types of rotating bolts, including rotating bolts under high temperature; during the use of the rotating bolt, the change of the pre-tightening force can be monitored in real time by continuously measuring the propagation speed of ultrasonic waves. Fourth, the designed multi-channel EMAT detection circuit adopts multiple functional modules. Through the precise control of the MOS transistor switch pulse width by the FPGA, the coil-type EMAT detection probe realizes the delicate adjustment of the excitation / reception of ultrasonic waves, thereby significantly improving the detection accuracy and stability. By using a specially designed trigger module, cooperating with a high-performance MOSFET driver I1 (IR2101) and MOS transistors, the fast switching of electromagnetic ultrasonic excitation is ensured, greatly enhancing the pulse intensity and frequency. The effective use of the high-voltage capacitor discharge module significantly improves the generation quality of ultrasonic signals and enhances the detection ability; while the low-voltage capacitor discharge module stably generates a bias magnetic field to ensure the long-term reliability of the system. The optimized design of the impedance matching module and the echo detection module effectively reduces signal distortion, improves the transmission efficiency and accurately captures ultrasonic signals.The introduction of the sampling current module realizes the real-time monitoring of the discharge current, simplifies the circuit state monitoring and debugging process. The overall design improves the performance and operation convenience of the detection system. Through modular design, it allows independent replacement of faulty modules, greatly improving the maintainability and scalability of the circuit. In addition, the integrated design reduces unnecessary components, optimizes the circuit layout, helps reduce costs, and improves economic benefits. Fifth, by adopting the advanced optimization algorithm and parallel processing ability of the FPGA processing module, the present invention realizes a significant improvement in the data processing speed, effectively enhances the data transmission efficiency, and ensures the speed and reliability of data transmission. In addition, the present invention introduces non-contact remote data transmission technology, realizes seamless connection, and significantly reduces the risks of physical and electromagnetic interference in traditional contact transmission. Considering the usage requirements in high-temperature environments, the system structure and working mechanism of the present invention are adaptively designed for high-temperature conditions to ensure that the system can maintain stability and security under extreme temperatures and is widely applicable to high-temperature environments. Compared with the traditional processing architecture, the data processing speed of the present invention is increased by at least five times, greatly improving the overall efficiency of the system; Sixth, an intelligent analysis terminal platform is designed to monitor and analyze the real-time and historical records of the pre-tightening force of rotating bolts under high-temperature conditions; compared with the traditional instantaneous monitoring method of the pre-tightening force of rotating bolts under high-temperature conditions, the safety of rotating bolts is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 : Schematic block diagram of an embodiment of the present application;

[0047] Figure 2 : Installation schematic diagram of the coil-only electromagnetic ultrasonic monitoring sensor of an embodiment of the present application;

[0048] Figure 3 : Schematic diagram of the electromagnetic ultrasonic transduction mechanism based on the Lorentz force;

[0049] Figure 4 : Schematic diagram of the electromagnetic ultrasonic transduction mechanism based on the magnetostrictive effect;

[0050] Figure 5 : Schematic diagram of the multi-channel EMAT detection circuit of an embodiment of the present application;

[0051] Figure 6 : Schematic diagram of the components of the intelligent analysis platform of an embodiment of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution of the present application will be further described in detail below in conjunction with the embodiments and drawings of the present application.

[0053] Existing ultrasonic detection methods include various types, such as piezoelectric ultrasonic, moiré ultrasonic at high temperature, electromagnetic ultrasonic, laser ultrasonic, and air-coupled ultrasonic, which are all widely used non-destructive testing technologies at present. However, for the detection of rotating bolts under high-temperature conditions, in a high-temperature environment, traditional coupling media will fail, and the performance of piezoelectric materials will also decline. It is necessary to develop piezoelectric materials and coupling agents that can work stably at high temperatures; the application of ultrasonic guided wave technology in high-temperature monitoring also faces some problems, such as the high-temperature resistance performance of sensors, the accuracy of data acquisition, etc. Laser ultrasonic and electromagnetic ultrasonic technologies are generally regarded as ideal choices for non-destructive testing in high-temperature environments due to their unique non-contact nature, the need not to use coupling agents, and the convenience of exciting ultrasonic waves. However, laser ultrasonic technology has limitations in practical applications due to its large equipment volume, high cost, and the fact that its working principle based on the ablation effect may cause damage to the surface of the object under test. In contrast, electromagnetic ultrasonic technology uses the Lorentz force and magnetostrictive effect to directly generate ultrasonic waves on metal samples, avoiding the need for contact and the use of coupling agents, and is suitable for non-destructive testing of rotating bolts in high-temperature and enclosed environments. Therefore, this application realizes the non-destructive detection of the pre-tightening force of rotating bolts in a high-temperature environment based on electromagnetic ultrasonic technology.

[0054] The present invention relates to a rotating bolt pre-tightening force monitoring device and method under high-temperature conditions, in particular to an Internet of Things monitoring solution capable of real-time monitoring of the pre-tightening force condition of a rotating bolt and realizing wireless data transmission. The device may include a magnetostrictive sheet, a single-coil EMAT (Electromagnetic Acoustic Transducer) detection probe, a multi-channel EMAT detection circuit, a signal processor, and an intelligent analysis terminal platform. By adhering the magnetostrictive sheet to the rotating bolt to ensure good coupling between the rotating bolt and the magnetostrictive sheet, and at the same time placing the single-coil EMAT detection probe at an appropriate position. The single-coil EMAT detection probe coil is passed through a discharge current containing high-frequency strong pulse components and quasi-DC components, driving the surface particles to vibrate in the vertical direction and causing strain deformation of the magnetostrictive patch in the horizontal direction, thereby generating longitudinal waves and shear waves respectively; the multi-channel EMAT detection circuit receives the echo signal of the rotating bolt and induces an electrical signal; the signal processor performs demodulation, filtering, amplification and decoding of the signal to extract relevant information of the rotating bolt pre-tightening force and detect the structural integrity of the rotating bolt. And the collected data and status information are sent to the external intelligent analysis terminal platform through the data transmission module for feature extraction, conversion and visualization of the rotating bolt pre-tightening force, realizing remote monitoring and analysis of the rotating bolt pre-tightening force under high-temperature conditions above 550 °C. The present invention adopts a magnetostrictive sheet, a single-coil EMAT detection probe and a signal processor, which have the characteristics of non-contact and high precision, and realizes the measurement of the pre-tightening force of a high-temperature rotating bolt; an intelligent analysis terminal platform is set up to realize remote wireless communication, breaking through the limitation that the traditional detection terminal is a local PC, and realizing on-line monitoring and data analysis of the rotating bolt pre-tightening force under high-temperature conditions based on Internet of Things wireless networking. The device of the present invention integrates functions of automatic state collection, intelligent analysis and visual display, enabling users to timely understand the pre-tightening force of the rotating bolt and make corresponding decisions, thereby improving the safety and efficiency of the rotating bolt.

[0055] Specific embodiments according to the present application will be described below with reference to the accompanying drawings.

[0056] As Figure 1 shown, an embodiment of the present application provides a rotating bolt pre-tightening force monitoring device under high-temperature conditions, including: a magnetostrictive sheet 102, a single-coil EMAT detection probe 103, a multi-channel EMAT detection circuit 104, and a signal processor 105; the magnetostrictive sheet 101 is coupled with the rotating bolt 102; the single-coil EMAT detection probe 103 is connected to the multi-channel EMAT detection circuit 104, and the signal processor 105 is connected to the multi-channel EMAT detection circuit 104;

[0057] The magnetostrictive sheet 102 is used to generate telescopic vibration under the action of a magnetic field, so as to generate ultrasonic waves on the surface of the rotating bolt 101;

[0058] The coil-only EMAT detection probe 103 is used to realize the excitation and reception of ultrasonic waves on the surface of the rotating bolt 101 through the magneto-acoustic effect;

[0059] The multi-channel EMAT detection circuit 104 is connected to the coil-only EMAT detection probe 103, and is used to continuously supply a quasi-direct current to the multiple coils while sequentially supplying a strong pulse current to each coil in a preset order, and to detect the echo signals received by each coil;

[0060] The signal processor 105 is used to analyze the echo signals received by the coil-only EMAT detection probe 103, and perform signal demodulation, filtering, amplification and decoding to extract the pre-tightening force information of the rotating bolt.

[0061] In some embodiments, the signal processor 105 may include a 16-bit AD high-speed analog-to-digital converter, an FPGA processing module and a data transmission module; the 16-bit AD high-speed analog-to-digital converter is connected to the FPGA processing module; the FPGA processing module is connected to the data transmission module;

[0062] The 16-bit AD high-speed analog-to-digital converter collects analog signals from the coil-only EMAT detection probe;

[0063] The FPGA processing module is used to perform real-time processing of signals according to specific algorithms, including filtering, feature extraction and waveform reconstruction, etc.;

[0064] In some embodiments, the data transmission module uses an ESP8266WIFI module with a heat dissipation design, supports long-term stable operation, and has high anti-interference ability; it can send the processed data to an external intelligent analysis terminal platform; at the same time, by setting heat sinks on the PCB and using heat dissipation materials with high conductivity, its usability in high-temperature environments can be improved, and it can work in a relatively high temperature range while maintaining a relatively low cost, so as to achieve a large number of applications.

[0065] In some embodiments, the monitoring device further includes an intelligent analysis terminal platform 106. The signal processor 105 is wirelessly connected to the intelligent analysis terminal platform 106. The signal processor 105 wirelessly transmits the processed data to the external intelligent analysis terminal platform 106.

[0066] The intelligent analysis terminal platform 106 is a software and hardware integrated system, which is used to receive, store, analyze and display data, mainly including data such as the pre-tightening force and defect location of the rotating bolt under high-temperature conditions;

[0067] As Figure 2 Figure 2 is an installation schematic diagram of a coil-only electromagnetic ultrasonic monitoring sensor, including a rotating bolt 201; a magnetostrictive sheet 202; a coil-only EMAT detection probe 203; the magnetostrictive sheet 202 is bonded to the rotating bolt through a high-temperature adhesive (such as RgDg-SF series carbon fiber reinforced adhesive); the coil-only EMAT detection probe 203 is located above the magnetostrictive sheet 202;

[0068] Figure 3 Figure 3 is a schematic diagram of the electromagnetic ultrasonic transducer mechanism based on the Lorentz force. When a discharge current containing high-frequency strong pulse components and quasi-DC components is passed through the coil 303, under the action of the quasi-DC component, a static magnetic induction intensity Bs can be generated in the magnetostrictive patch 302. Under the action of the high-frequency strong pulse component, an eddy current Jiz can be generated in the magnetostrictive patch. The combined action of the static magnetic field and the eddy current can generate a Lorentz force on the surface of the rotating bolt 301, driving the surface particles to vibrate in the vertical direction, thereby generating longitudinal waves. The pre-tightening force of the rotating bolt 301 is detected.

[0069] Figure 4 Figure 4 is a schematic diagram of the electromagnetic ultrasonic transducer mechanism based on the magnetostrictive effect. When a discharge current containing high-frequency strong pulse components and quasi-DC components is passed through the coil 403, under the action of the quasi-DC component, a static magnetic field Hs can be generated in the magnetostrictive patch 402 to orient the magnetic domains in the magnetostrictive patch, aiming to enhance the magnetostrictive effect. Under the action of the high-frequency strong pulse component, a dynamic magnetic field Hd can be generated in the magnetostrictive patch 402, driving the magnetostrictive patch 402 to generate strain deformation in the horizontal direction, thereby generating shear waves. The shear waves propagate downward along the rotating bolt 401, and the pre-tightening force of the rotating bolt 401 can be detected.

[0070] Figure 5It is a schematic diagram of the multi-channel EMAT detection circuit, including a trigger module 501, a high-voltage capacitor discharge module 502, a low-voltage capacitor discharge module 503, an echo detection module 504, a sampling current module 505, and an impedance matching module 506. Among them, the trigger module 501 is composed of a dedicated MOSFET driver I1 ((IR2101)) and MOS transistors, which can provide a more stable MOSFET drive signal. Its pulse width is controlled by the FPGA to adjust the MOS transistor switch, so as to realize the excitation / reception of electromagnetic ultrasonic signals of a single coil of the coil-type EMAT detection probe only. The high-voltage capacitor discharge module 502 generates a strong pulse current and introduces it into the coil-type EMAT detection probe only. At the same time, it uses a movie-grade capacitor (such as AVX MLPC1025A105K), which has high withstand voltage and low ESR. The low-voltage capacitor discharge module 503 uses a ceramic capacitor (such as the Panasonic ECG series) to provide a stable DC current, and provides a smooth quasi-DC current through C2 to generate a bias magnetic field. The impedance matching module 504 optimizes the impedance of the coil-type EMAT detection probe only by adjusting the parameters of the adjustable inductor L2 (such as Coilcraft0603NL-2N2) and the adjustable capacitor C4 (such as Multicomp MKP-1V622). The echo detection module 506 captures the echo signal of the ultrasonic wave reflected by the pre-tightening force inside the rotating bolt through C5 coupling, D2 / D3 / R7 limiting filtering, and further filtering by C6. In particular, the sampling current module 505 is connected to the impedance matching module 506 through a wire. The sampling current module observes the discharge current through a sampling resistor to judge the working state of the multi-channel EMAT detection circuit and the waveform and amplitude of the discharge current.

[0071] Figure 6 It is a schematic diagram of the composition of the intelligent analysis platform: including a data receiving module 106-1 (such as a wireless network card or a USB WiFi receiver, etc.), a storage management system 106-2 (such as a high-speed storage device SSD, etc.), a data preprocessing module 106-3 (such as data cleaning tools Pandas, NumPy, etc.), a data processing and analysis module 106-4 (such as data analysis software Excel, MATLAB, etc.), and a real-time image generation module 106-5 (such as a graphics processing unit GPU and image processing libraries OpenCV, Matplotlib, etc.); the data receiving module 106-1 is connected to the storage management system 106-2, and the storage management system 106-2 is connected to the data preprocessing module 106-3; the data processing and analysis module 106-4 is connected to the real-time image generation module 106-5;

[0072] The data receiving module 106-1 receives WiFi data from the external network and is connected to the main computer system through USB or Wi-Fi.

[0073] The storage management system 106-2 receives data from the data receiving module 106-1 via a network or a high-speed interface, and stores and manages the data from the data receiving module 106-1;

[0074] The data preprocessing module 106-3 cleans, filters, and transforms the data to make it suitable for further analysis and processing;

[0075] The data processing and analysis module 106-4 performs data mining, statistical analysis, machine learning algorithms, etc. to extract insights and patterns from the data, and extracts and transforms the pre-tightening force characteristic values of the rotating bolt.

[0076] An embodiment of the present application further provides a method for monitoring the pre-tightening force of a rotating bolt under high-temperature conditions, which uses the above-mentioned monitoring device to realize ultrasonic monitoring of the pre-tightening force of the rotating bolt under high-temperature conditions. The working process may include:

[0077] First, a magnetostrictive sheet is coupled to the surface of the rotating bolt using a high-temperature adhesive (such as the RgDg-SF series carbon fiber-reinforced adhesive), and a coil-only EMAT detection probe is placed around the rotating bolt to form a coil-only sensor with high-temperature thermal stability;

[0078] In the subsequent initial stage, the FPGA module and the MOS isolation driver chip are connected in series, controlled by the same timing, and a weak low-voltage pulse trigger signal is input. The driver chip then boosts the power of the trigger signal generated by the FPGA module to ensure that the gate voltage of the MOS transistor can quickly rise, thereby realizing the fast conduction and closing of the MOS transistor. At the same time, the high-voltage capacitor discharge module performs transient charging and discharging through a capacitor bank under the switching control of the MOS transistor, generating a periodic and high-intensity excitation current. With the Lorentz force and magnetostrictive effect, this current excites an alternating strong pulse in the coil, and then generates a corresponding Lorentz force and magnetostrictive strain in the magnetostrictive patch, pushing the particles on the patch surface to vibrate, thereby generating active ultrasonic waves.

[0079] On the other hand, in the low-voltage capacitor discharge module, the charge and discharge are controlled by a switching module with an internal IGBT, and the charge and discharge process takes a relatively long time. This module can generate a relatively long-lasting and stable approximately direct-current excitation current in the coil, providing a constant background magnetic field and magnetic induction intensity for ultrasonic echo detection.

[0080] The high-voltage capacitor discharge module and the low-voltage capacitor discharge module are connected in parallel with each other and are controlled by independent timing. When the DC-like component reaches its maximum, the high-voltage capacitor discharge module is started to generate strong pulses, which can greatly increase the excitation efficiency of ultrasonic waves. The on-duration period of the low-voltage capacitor discharge module is significantly longer than that of the high-voltage capacitor discharge module, and the high-voltage capacitor discharge module is started at the moment when the DC-like current in the coil rises to its peak value (i.e., when the magnetic field is the strongest). This move aims to maximize the amplitude of the ultrasonic waves excited by the magnetostrictive sheet.

[0081] In addition, the impedance matching module effectively ensures the highest voltage division of the energy of the induced electromotive force on the echo detection module, thereby enhancing the intensity and signal-to-noise ratio of the ultrasonic echo signal. The echo detection module has the ability to capture and process echo signals, including filtering and amplifying them.

[0082] Secondly, a 16-bit AD high-speed analog-to-digital converter collects analog signals from a coil-only EMAT detection probe and converts them into digital signals in combination with an FPGA; through a data transmission module, the data is sent to an external device;

[0083] Finally, the integrated platform receives and stores data from the detector, and performs data analysis, pre-tightening force eigenvalue extraction and processing; the monitoring data is visualized through a graphical interface, and users can intuitively view the current pre-tightening force state and historical data of the rotating bolt.

[0084] In the description of the embodiments of the present application, the principles and formulas involved in the process of extracting the pre-tightening force eigenvalue of the rotating bolt are as follows:

[0085] When the rotating bolt is subjected to a pre-tightening force, internal strain will be generated in the material of the rotating bolt. According to Hooke's Law, there is a linear relationship between stress and strain, that is, stress is proportional to strain. In this formula, the pre-tightening force is related to the elastic modulus of the material of the rotating bolt and the axial length change . Ultrasonic waves are high-frequency sound waves that can propagate in materials. When ultrasonic waves pass through the rotating bolt, their propagation speed will be affected by the internal stress distribution of the material. The increase in the pre-tightening force will change the stress state of the material, thereby changing the propagation speed of ultrasonic waves. Specifically: in the rotating bolt, shear waves can only propagate in longitudinal vibrations and cannot propagate in transverse vibrations. The propagation speed of shear waves is related to the shear modulus of the material. Longitudinal waves can propagate in the material with both longitudinal and transverse vibrations. The propagation speed of longitudinal waves is related to the Young's modulus of the material. Since the pre-tightening force affects the stress state of the material, the propagation speeds of both shear waves and longitudinal waves will change. By measuring the propagation time of these two waves in the rotating bolt, the axial length change can be calculated, and thus the pre-tightening force can be estimated.

[0086]

[0087]

[0088] Wherein: is the pre-tightening force of the rotating bolt (N), is the elastic modulus of the rotating bolt material (N / mm² or MPa), is the cross-sectional area of the rotating bolt (mm²), usually the product of π / 4 of the square of the diameter (d) of the rotating bolt, is the axial length change of the rotating bolt (mm), which is obtained by measuring the propagation time difference between the transverse wave and the longitudinal wave, is the natural length of the rotating bolt (mm), is the density of the rotating bolt material (unit: kg / m³), is the propagation time difference between the transverse wave and the longitudinal wave (unit: s); is the propagation speed of ultrasonic waves in the rotating bolt material (mm / μs), and this value depends on the type of material and the temperature during detection. Usually, the longitudinal ultrasonic wave is selected as the measurement object, that is take the propagation speed of the longitudinal wave in the rotating bolt material.

[0089] The specific steps are as follows: First, find the elastic modulus E of the rotating bolt material and the propagation speed λ of ultrasonic waves; measure the natural length of the rotating bolt without applying pre-tightening force ; make the rotating bolt in the working state; the probe excites and emits transverse and longitudinal ultrasonic waves through the rotating bolt, and measures their propagation time in the rotating bolt; according to the propagation time difference between the transverse wave and the longitudinal wave, the axial length change of the rotating bolt can be calculated; finally, use the above formula to calculate the pre-tightening force.

[0090] By accurately measuring the propagation time of ultrasonic waves, a very accurate axial length change can be calculated, so as to obtain a high measurement accuracy of the pre-tightening force; it is applicable to various materials and types of rotating bolts, including rotating bolts at high temperatures; during the use of the rotating bolt, the change of the pre-tightening force can be monitored in real time by continuously measuring the propagation speed of ultrasonic waves.

[0091] The real-time image generation module 106-5 generates a real-time image or visualization effect according to the analysis result, so as to facilitate the user to intuitively understand the data and discovery.

[0092] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A rotating bolt preload monitoring device under high temperature conditions, characterized in that: include: A magnetostrictive sheet, a coil-only EMAT detection probe, a multi-channel EMAT detection circuit and a signal processor; during monitoring, the magnetostrictive sheet is coupled to a rotating bolt, and the coil-only EMAT detection probe is placed around the rotating bolt; the coil-only EMAT detection probe, the multi-channel EMAT detection circuit and the signal processor are connected in sequence; The multi-channel EMAT detection circuit is used to continuously pass a quasi-DC current into the multiple coils of the coil-only EMAT detection probe and simultaneously pass a strong pulse current into each coil in sequence according to a preset order; The coil-only EMAT detection probe includes a plurality of coils for generating a magnetic field under the action of a quasi-DC current; The magnetostrictive sheet is used to generate stretching vibration in a magnetic field, thereby generating ultrasonic waves on the surface of the rotating bolt; The coil-only EMAT detection probe is also used to receive the ultrasonic echo signal; The multi-channel EMAT detection circuit is also used to detect the echo signal received by each coil of the coil-only EMAT detection probe; The signal processor is used to analyze the echo signal detected by the multi-channel EMAT detection circuit and extract the preload force information of the rotating bolt.

2. The monitoring device according to claim 1, characterized in that: The multi-channel EMAT detection circuit includes a trigger module, a high-voltage capacitor discharge module, a low-voltage capacitor discharge module, an impedance matching module and an echo detection module; the trigger module, the high-voltage capacitor discharge module and the low-voltage capacitor discharge module are electrically connected in sequence; The low-voltage capacitor discharge module, the impedance matching module, and the echo detection module are all electrically connected to the coil of the coil-only EMAT detection probe; The trigger module and the echo detection module are electrically connected to the signal processor.

3. The monitoring device according to claim 2, characterized in that: The multi-channel EMAT detection circuit also includes a sampling current module, which is electrically connected to the impedance matching module; the sampling current module observes the discharge current of the multi-channel EMAT detection circuit through a sampling resistor to determine the working state of the multi-channel EMAT detection circuit and the discharge current waveform and amplitude.

4. The monitoring device according to claim 1, characterized in that: The signal processor comprises: a 16-bit AD high-speed analog-to-digital converter and an FPGA processing module; the 16-bit AD high-speed analog-to-digital converter is connected to the FPGA processing module; The 16-bit AD high-speed analog-to-digital converter receives the analog signal from the coil-only EMAT detection probe and performs analog-to-digital conversion to obtain a digital signal; The FPGA processing module is used to process the digital signal in real time and extract the preload force information of the rotating bolt.

5. The monitoring device according to claim 4, characterized in that: The signal processor also includes a data transmission module; the data transmission module is connected to the FPGA processing module; and is used to send the data processed by the FPGA processing module to an external intelligent analysis terminal platform.

6. The monitoring device according to claim 5, characterized in that: The data transmission module adopts the ESP8266WIFI module with heat dissipation design.

7. The monitoring device according to claim 6, characterized in that: The PCB of the signal processor is provided with a heat sink, and uses a heat dissipation material with high conductivity.

8. The monitoring device according to any one of claims 1 to 7, characterized in that: It also includes an intelligent analysis terminal platform, the signal processor and the intelligent analysis terminal platform are wirelessly connected, and the signal processor wirelessly transmits the extracted rotating bolt preload information to the intelligent analysis terminal platform; The intelligent analysis terminal platform is used to receive, store, analyze and display the rotating bolt preload information.

9. A method for ultrasonic monitoring of the preload force of a rotating bolt under high temperature conditions, characterized in that: The monitoring device described in any one of claims 1 to 8 is used to realize ultrasonic monitoring of the preload force of rotating bolts under high temperature conditions.

10. The monitoring device according to claim 9, characterized in that: A quasi-DC current is continuously supplied to the multiple coils of the coil-only EMAT detection probe, and a strong pulse current is sequentially supplied to each coil in a preset order; the particles on the surface of the rotating bolt are driven to vibrate in the vertical direction, and the magnetostrictive patch is strained and deformed in the horizontal direction, thereby generating longitudinal waves and transverse waves respectively; the propagation time of the longitudinal wave and the transverse wave in the rotating bolt is measured based on the echo signal, and the axial length change of the rotating bolt is calculated , and then the preload force is estimated according to the following formula: ； ； in: is the preload force of the rotating bolt, is the elastic modulus of the rotating bolt material, is the cross-sectional area of ​​the rotating bolt, is the natural length of the rotating bolt, is the material density of the rotating bolt, is the propagation time difference between the transverse wave and the longitudinal wave; λ is the propagation speed of the ultrasonic wave in the rotating bolt.

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