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

Abstract

The utility model provides a swivel bolt pretightening force monitoring device 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 supplies discharge current to the plurality of coils of the detection probe; a plurality of coils of the detection probe generate a magnetic field under the action of the 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 field of measuring the preload of rotating bolts, and specifically relates to a device for monitoring the preload of rotating bolts under high temperature conditions. Background Technology

[0002] Rotary bolt connections are fundamental components of many structural and mechanical systems. Proper preload ensures that the bolts do not loosen or break under load, thus maintaining the safety of the entire structure. Improper preload, whether too tight or too loose, can lead to connection failure, increasing the risk of accidents and malfunctions. In many mechanical applications, such as engine assembly and machine installation, the lack of online non-destructive testing and monitoring technology makes it impossible to accurately measure the preload of rotary bolts. This has forced these devices to shut down, and even triggered serious accidents such as equipment cracking, gas leaks, and explosions, resulting in significant personal injury and economic losses.

[0003] Currently, the lifespan of rotating bolts in many power plants and petrochemical enterprises has far exceeded their design lifespan. However, due to the difficulty of replacing rotating bolts, the need for continuous operation, and the enormous costs and economic losses from large-scale replacement of high-temperature rotating bolts and production stoppages, it is necessary to monitor the preload of rotating bolts in real time to provide early warning of potential bolt failure risks.

[0004] In high-temperature and high-pressure environments, the temperature of rotating bolts can exceed 550°C, and they are often located in inaccessible positions, making conventional testing methods difficult to implement. Existing methods for testing the preload of rotating bolts under high-temperature conditions mostly involve periodic non-destructive testing and inspection during shutdown. Due to the large scale and complex structure of high-temperature equipment, the accessibility of testing is poor, and manual testing is usually required, resulting in low testing efficiency and a heavy workload.

[0005] Therefore, there is an urgent need to develop a new type of rotating bolt preload monitoring device under high temperature conditions. Utility Model Content

[0006] The purpose of this invention is to provide a device for monitoring the preload of rotating bolts under high temperature conditions, which can realize online monitoring of the preload of rotating bolts under high temperature conditions.

[0007] To achieve the above objectives, this utility model provides the following solution:

[0008] A device for monitoring the preload of a rotating bolt under high temperature conditions includes: 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 the 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.

[0009] The functions of each module in this device are as follows:

[0010] The multi-channel EMAT detection circuit can continuously supply a DC-like current to multiple coils of the coil-only EMAT detection probe, while simultaneously supplying a strong pulse current to each coil in a preset order, and detecting the echo signal received by each coil. This multi-channel signal synchronization ensures that the echo signals received by different coils are consistent in time. At the same time, by comparing the echo signals received by different coils, the preload value in different directions or positions can be identified to obtain more comprehensive and accurate information for detection.

[0011] The coil-only EMAT detection probe includes multiple coils, which can generate a magnetic field when a DC-like current is applied.

[0012] The magnetostrictive sheet can generate stretching vibrations in a magnetic field, thereby generating ultrasonic waves on the surface of the rotating bolt;

[0013] The coil-only EMAT detection probe can also receive the echo signal of the ultrasonic wave;

[0014] The multi-channel EMAT detection circuit can also detect the echo signal received by each coil of the coil-type EMAT detection probe.

[0015] The signal processor can analyze the echo signal detected by the multi-channel EMAT detection circuit and extract the preload information of the rotating bolt.

[0016] The signal processor can perform signal demodulation, filtering, amplification, and decoding to extract information about the preload of the rotating bolt.

[0017] Each coil in the coil-only EMAT detection probe can work independently. By using multiple coils in combination, multiple coils can perform independent detection at the same time, which improves the efficiency and speed of detection, enhances signal coverage, and realizes multi-channel detection.

[0018] By detecting the echo signal received by each coil and combining it with the sequence of strong pulse current applied to each coil, multi-channel signal synchronization can be achieved, ensuring that the echo signals received by different coils are consistent in time. At the same time, by comparing the echo signals received by different coils, the preload value in different directions or positions can be identified, so as to obtain more comprehensive and accurate information for detection.

[0019] Furthermore, the magnetostrictive sheet is made of ferromagnetic material, specifically a vanadium-iron intermetallic compound magnetostrictive sheet with a thickness of 0.5 mm. This material has detectable deformation, a melting point far exceeding 550°C, good high-temperature resistance, and can deform under the influence of a magnetic field, with a magnetostrictive coefficient as high as 2000 to 4000 ppm.

[0020] Furthermore, the coil of the coil-only EMAT detection probe is one of the following: a runway coil, a spiral coil, or a butterfly coil.

[0021] 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 coil-only EMAT detection probe.

[0022] The triggering module and the echo detection module are electrically connected to the signal processor.

[0023] Furthermore, the multi-channel EMAT detection circuit also includes a sampling current module, which is electrically connected to the impedance matching module.

[0024] The sampling current module and the impedance matching module are connected by a wire. The sampling current module observes the discharge current through a sampling resistor to determine the operating status, discharge current waveform, and amplitude of the multi-channel EMAT detection circuit.

[0025] Furthermore, the signal processor includes: a 16-bit high-speed analog-to-digital converter, a field-programmable gate array (FPGA) processing module, and a data transmission module; the 16-bit high-speed analog-to-digital converter is connected to the FPGA processing module; the FPGA processing module is connected to the data transmission module.

[0026] The 16-bit high-speed analog-to-digital converter receives analog signals from a coil-only EMAT detection probe.

[0027] Furthermore, the FPGA processing module can perform real-time signal processing based on a specific algorithm to extract the preload information of the rotating bolt.

[0028] Real-time signal processing includes filtering, feature extraction, and waveform reconstruction.

[0029] Furthermore, the data transmission module adopts an ESP8266WIFI module with heat dissipation design, which supports long-term stable operation and has high anti-interference capability; it can send the processed data to an external intelligent analysis terminal platform.

[0030] Furthermore, the signal processor's PCB is equipped with a heat sink and uses a high-conductivity heat dissipation material. This improves its ability to operate in high-temperature environments, enabling it to work over a wider temperature range while maintaining relatively low cost, thus facilitating its widespread application.

[0031] Traditional high-temperature rotating bolt monitoring technology still suffers from the limitations of wired transmission in terms of data transmission, resulting in complex wiring and poor detection feasibility. Corresponding wireless transmission is still in the experimental research and development stage, with extremely high costs hindering large-scale application. This invention, by employing an FPGA processing module, leverages its advanced optimization algorithms and parallel processing capabilities to significantly improve data processing speed, effectively enhancing data transmission efficiency and ensuring fast and reliable data transmission. Furthermore, this invention introduces a non-contact remote data transmission module, achieving seamless connection and significantly reducing the physical and electromagnetic interference risks associated with traditional contact-based transmission.

[0032] Furthermore, the heat sink adopts a single-wing or double-wing design to optimize airflow and reduce drag.

[0033] Furthermore, the heat dissipation material is made of aluminum, which has the characteristics of low cost, easy processing, and good thermal conductivity.

[0034] Furthermore, the monitoring device also 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 preload information of the rotating bolt to the intelligent analysis terminal platform.

[0035] Furthermore, the signal processor and the intelligent analysis terminal platform are wirelessly connected.

[0036] The intelligent analysis terminal platform is an integrated hardware and software platform that can receive, store, analyze, and display data, mainly including information such as the preload of rotating bolts. Therefore, it allows for real-time remote online monitoring of the preload of rotating bolts under current high-temperature conditions, achieving automatic status acquisition, intelligent conversion, and visual display functions.

[0037] Furthermore, 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, which is connected to the data preprocessing module. The data preprocessing module is connected to the data processing and analysis module, and the data processing and analysis module is connected to the real-time image generation module. The storage management system manages the received data, including using a database and file system. The data preprocessing module performs filtering, noise reduction, and other preprocessing on the raw data. The data processing and analysis module performs algorithmic processing and analysis on the preprocessed data to extract the characteristic values ​​of the preload of the rotating bolt under high-temperature conditions. The real-time image generation module generates and displays images in real time based on the processing results.

[0038] Furthermore, the visualization display adopts intelligent monitoring technology to display the operating status and fault alarm indicators of IoT devices, including the power and power consumption of IoT devices, the magnitude and trend of the preload of rotating bolts, the historical records of the preload of rotating bolts over a period of time, records of abnormal values ​​of the preload of rotating bolts, the duration of the preload of rotating bolts, and the distribution of the preload of rotating bolts.

[0039] Recording the preload testing process of rotating bolts under high-temperature conditions is challenging. Traditional high-temperature rotating bolt monitoring technologies suffer from intermittent data storage, making real-time data preservation and analysis extremely difficult. The lack of long-term data recording hinders effective historical tracking and trend analysis of the operating status of rotating bolts under high-temperature conditions, thus limiting the prediction of potential problems and the development of preventative measures. This application designs an intelligent analysis terminal platform to monitor and analyze the actual and historical preload of rotating bolts under high-temperature conditions in real time, facilitating regular inspection and maintenance.

[0040] Beneficial effects:

[0041] This utility model provides a rotating bolt preload monitoring device under high temperature conditions, which has 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 preload of rotating bolts at high temperature through signal reception and transmission of the coil-only EMAT detection probe. Compared with traditional magnetostrictive ultrasonic sensors, it does not require an external permanent magnet or periodic magnetization of the permanent magnet. It is small in size and can be used for detection in a confined space. Its bias magnetic field is provided by a coil with a DC-like current, and the magnetic field strength will not gradually weaken over time. It also avoids the demagnetization or even demagnetization of the residual magnetism of the magnetostrictive patch after magnetization by a permanent magnet due to temperature and time. Second, the coil-only EMAT detection probe includes multiple coils, each of which can work independently. Through the coordinated use of multiple coils, multiple coils can perform independent detection at the same time, which improves the detection efficiency and speed, enhances signal coverage, and realizes multi-channel detection. Based on the echo signal received by each coil, and combined with the sequence of strong pulse current applied to each coil, multi-channel signal synchronization is performed to ensure that the echo signals received by different coils are consistent in time. Simultaneously, the echo signals received by different coils are compared to identify the preload value in different directions or positions, thus obtaining more comprehensive and accurate information for detection. Third, while continuously applying a DC-like current to multiple coils of the coil-only EMAT detection probe, strong pulse current is sequentially applied to each coil in a preset order; this causes the particles on the surface of the rotating bolt to vibrate vertically and the magnetostrictive patch to undergo strain deformation horizontally, thereby generating longitudinal and transverse waves respectively. By measuring the propagation time of the longitudinal and transverse waves in the rotating bolt based on the echo signal, the axial length change of the rotating bolt can be calculated very accurately, and the preload can be estimated according to the formula, resulting in high preload measurement accuracy. This method is applicable to rotating bolts of various materials and types, including those operating at high temperatures. During the use of the rotating bolt, the change in preload can be monitored in real time by continuously measuring the propagation speed of the ultrasonic wave. Fourth, the designed multi-channel EMAT detection circuit employs multiple functional modules. Precise control of the MOSFET switching pulse width via FPGA enables fine adjustment of the coil-type EMAT detection probe's excitation / reception of ultrasonic waves, significantly improving detection accuracy and stability. A specially designed trigger module, combined with a high-efficiency MOSFET driver I1 (IR2101) and MOSFETs, ensures rapid switching of electromagnetic ultrasonic excitation, greatly enhancing pulse intensity and frequency. The effective use of the high-voltage capacitor discharge module significantly improves the quality of ultrasonic signal generation and enhances detection capabilities; while the low-voltage capacitor discharge module stably generates a bias magnetic field, ensuring the long-term reliability of the system. The optimized design of the impedance matching module and echo detection module effectively reduces signal distortion, improves transmission efficiency, and accurately captures ultrasonic signals.The introduction of the sampling current module enables real-time monitoring of the discharge current, simplifying circuit status monitoring and debugging processes. The overall design improves the performance and ease of operation of the detection system. Modular design allows for independent replacement of faulty modules, significantly improving circuit maintainability and scalability. Furthermore, integrated design reduces unnecessary components and optimizes circuit layout, helping to lower costs and improve economic efficiency. Fifth, this invention employs an FPGA processing module, leveraging its advanced optimization algorithms and parallel processing capabilities to significantly improve data processing speed, effectively enhancing data transmission efficiency and ensuring fast and reliable data transmission. In addition, this invention introduces a non-contact remote data transmission module, achieving seamless connection and significantly reducing the physical and electromagnetic interference risks associated with traditional contact-based transmission. Considering the requirements for use in high-temperature environments, the system structure and working mechanism of this invention are adapted to high-temperature conditions, ensuring the system maintains stability and safety under extreme temperatures, making it widely applicable to high-temperature environments. Compared with the traditional processing architecture, the data processing speed of this utility model is increased by at least five times, which greatly improves the overall efficiency of the system; sixth, an intelligent analysis terminal platform is designed to monitor and analyze the actual and historical data of the preload of rotating bolts under high temperature conditions in real time; compared with the traditional instantaneous monitoring method of the preload of rotating bolts under high temperature conditions, the safety of rotating bolts is greatly improved. Attached Figure Description

[0042] Figure 1 : A schematic block diagram of one embodiment of this application;

[0043] Figure 2 This application provides an embodiment of a coil-only electromagnetic ultrasonic monitoring sensor, which is shown in the following diagram.

[0044] Figure 3 Schematic diagram of electromagnetic ultrasonic transduction mechanism based on Lorentz force;

[0045] Figure 4 Schematic diagram of electromagnetic ultrasonic transduction mechanism based on magnetostriction effect;

[0046] Figure 5 : A schematic diagram of a multi-channel EMAT detection circuit according to an embodiment of this application;

[0047] Figure 6 : A schematic diagram of the components of an intelligent analysis platform according to an embodiment of this application. Detailed Implementation

[0048] To enable those skilled in the art to better understand the present application, the technical solution of the present application will be further described in detail below with reference to the embodiments and accompanying drawings.

[0049] Existing ultrasonic testing methods include various types, such as piezoelectric ultrasound, high-temperature moiré ultrasound, electromagnetic ultrasound, laser ultrasound, and air-coupled ultrasound, all of which are widely used non-destructive testing techniques. However, for the inspection of rotating bolts under high-temperature conditions, traditional coupling media fail, and the performance of piezoelectric materials degrades. Therefore, it is necessary to develop piezoelectric materials and coupling agents that can operate stably at high temperatures. The application of ultrasonic guided wave technology in high-temperature monitoring also faces some challenges, such as the high-temperature resistance of sensors and the accuracy of data acquisition. Laser ultrasound and electromagnetic ultrasound technologies are generally considered ideal choices for non-destructive testing in high-temperature environments due to their unique non-contact nature, the absence of coupling agents, and the ease of generating ultrasonic waves. However, laser ultrasound technology has limitations in practical applications due to the large size and high cost of the equipment, and its ablation-based working principle may damage the surface of the object being tested. In contrast, electromagnetic ultrasound technology utilizes the Lorentz force and magnetostrictive effect to directly generate ultrasonic waves on metal samples, avoiding contact and the need for coupling agents, making it suitable for non-destructive testing of rotating bolts in high-temperature and enclosed environments. Therefore, this application realizes non-destructive testing of the preload of rotating bolts under high temperature environment based on electromagnetic ultrasonic technology.

[0050] This utility model relates to a device for monitoring the preload of rotating bolts under high-temperature conditions, and more particularly to an IoT monitoring solution capable of real-time monitoring of the preload of rotating bolts and achieving wireless data transmission. The device may include a magnetostrictive sheet, a coil-only EMAT (Electromagnetic Acoustic Transducer) probe, a multi-channel EMAT detection circuit, a signal processor, and an intelligent analysis terminal platform. By attaching the magnetostrictive sheet to the rotating bolt, ensuring good coupling between the bolt and the magnetostrictive sheet, and placing the coil-only EMAT probe in a suitable position, the coil of the probe is supplied with a discharge current containing high-frequency strong pulse components and DC-like components. This causes surface particles to vibrate vertically, and the magnetostrictive sheet to undergo strain deformation horizontally, thereby generating longitudinal and transverse waves, respectively. The multi-channel EMAT detection circuit receives the echo signal from the rotating bolt and induces an electrical signal. The signal processor performs demodulation, filtering, amplification, and decoding of the signal to extract relevant information about the preload of the rotating bolt and detect the structural integrity of the bolt. The collected data and status information are transmitted via a data transmission module to an external intelligent analysis terminal platform for feature extraction, conversion, and visualization of the preload force of rotating bolts, enabling remote monitoring and analysis of the preload force of rotating bolts under high-temperature conditions exceeding 550°C. This invention employs a magnetostrictive sheet, a coil-only EMAT detection probe, and a signal processor, featuring non-contact and high-precision characteristics, achieving measurement of the preload force of rotating bolts at high temperatures. The intelligent analysis terminal platform enables remote wireless communication, overcoming the limitations of traditional local PC-based detection terminals, and realizing online monitoring and data analysis of the preload force of rotating bolts under high-temperature conditions based on IoT wireless networking. This device integrates automatic status acquisition, intelligent analysis, and visualization functions, allowing users to promptly understand the preload force of rotating bolts and make corresponding decisions, thereby improving the safety and efficiency of rotating bolts.

[0051] Specific embodiments according to this application will now be described with reference to the accompanying drawings.

[0052] like Figure 1 As shown, this application provides a rotating bolt preload monitoring device under high temperature conditions, including: a magnetostrictive sheet 102, a coil-only EMAT detection probe 103, a multi-channel EMAT detection circuit 104, and a signal processor 105; the magnetostrictive sheet 102 is coupled to the rotating bolt 102; the coil-only 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.

[0053] The functions of each module in this device are as follows:

[0054] The magnetostrictive sheet 102 can generate expansion and contraction vibrations under the action of a magnetic field, thereby generating ultrasonic waves on the surface of the rotating bolt 101;

[0055] The coil-only EMAT detection probe 103 can achieve ultrasonic excitation and reception on the surface of the rotating bolt 101 through the magneto-acoustic effect;

[0056] The multi-channel EMAT detection circuit 104 is connected to the coil-only EMAT detection probe 103, and can continuously supply a DC-like current to the multiple coils while sequentially supplying a strong pulse current to each coil in a preset order, and detect the echo signal received by each coil.

[0057] The signal processor 105 can analyze the echo signal received by the coil-only EMAT detection probe 103, and perform signal demodulation, filtering, amplification and interpretation to extract the preload information of the rotating bolt.

[0058] In some embodiments, the signal processor 105 may include a 16-bit high-speed analog-to-digital converter, an FPGA processing module, and a data transmission module; the 16-bit high-speed analog-to-digital converter is connected to the FPGA processing module; the FPGA processing module is connected to the data transmission module.

[0059] The 16-bit AD high-speed analog-to-digital converter acquires analog signals from a coil-only EMAT detection probe;

[0060] The FPGA processing module can perform real-time signal processing according to specific algorithms, including filtering, feature extraction, and waveform reconstruction.

[0061] In some embodiments, the data transmission module adopts an ESP8266WIFI module with heat dissipation design, which supports long-term stable operation and has high anti-interference capability; 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 ability to operate in high-temperature environments can be improved, enabling it to work in a high temperature range while maintaining a relatively low cost, thereby enabling a wide range of applications.

[0062] 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.

[0063] The intelligent analysis terminal platform 106 is a hardware and software integrated system that can receive, store, analyze and display data, mainly including data such as the preload and defect location of rotating bolts under high temperature conditions.

[0064] like Figure 2 This is an installation diagram of a coil-only electromagnetic ultrasonic monitoring sensor, including a rotating bolt 201; a magnetostrictive sheet 202; and a coil-only EMAT detection probe 203. The magnetostrictive sheet 202 is bonded to the rotating bolt with 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.

[0065] Figure 3 This diagram illustrates the electromagnetic ultrasonic transduction mechanism based on the Lorentz force. When a discharge current containing a high-frequency, high-pulse component and a near-DC component is passed through coil 303, a static magnetic induction intensity Bs is generated in the magnetostrictive patch 302 under the influence of the near-DC component, and an eddy current Jiz is generated in the magnetostrictive patch under the influence of the high-frequency, high-pulse component. The combined effect of the static magnetic field and the eddy current generates a Lorentz force on the surface of the rotating bolt 301, causing surface particles to vibrate in the vertical direction, thereby generating longitudinal waves. The preload of the rotating bolt 301 is then detected.

[0066] Figure 4 A schematic diagram of the electromagnetic ultrasonic transduction mechanism based on the magnetostrictive effect shows that when a discharge current containing high-frequency strong pulse components and a DC-like component is passed through the coil 403, a static magnetic field Hs is generated in the magnetostrictive patch 402 under the influence of the DC-like component. This magnetic field orients the magnetic domains in the magnetostrictive patch, thereby enhancing the magnetostrictive effect. Under the influence of the high-frequency strong pulse component, the coil generates a dynamic magnetic field Hd in the magnetostrictive patch 402, causing the patch to undergo strain deformation in the horizontal direction, thus generating a transverse wave. The transverse wave propagates downward along the rotating bolt 401, which can be used to detect the preload of the rotating bolt 401.

[0067] Figure 5This 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. The trigger module 501 uses a dedicated MOSFET driver I1 (IR2101) and a MOSFET, providing a more stable MOSFET drive signal. Its pulse width is controlled by an FPGA to adjust the MOSFET switching, enabling excitation / reception of the electromagnetic ultrasonic signal from a single coil of the coil-only EMAT detection probe. The high-voltage capacitor discharge module 502 generates a strong pulse current introduced into the coil-only EMAT detection probe, and uses a cinema-grade capacitor (such as AVX MLPC1025A105K) with high withstand voltage and low ESR. The low-voltage capacitor discharge module 503 uses ceramic capacitors (such as Panasonic). The ECG series provides a stable DC current, and C2 provides a smooth DC-like current to generate a bias magnetic field. The impedance matching module 504 optimizes the impedance of the coil-only EMAT detection probe 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 uses C5 coupling, D2 / D3 / R7 amplitude limiting filtering, and C6 further filtering to capture the echo signal of the ultrasonic waves reflected by the preload inside the rotating bolt. In particular, the sampling current module 505 is connected to the impedance matching module 506 via a wire. The sampling current module observes the discharge current through the sampling resistor to determine the operating status of the multi-channel EMAT detection circuit and the waveform and amplitude of the discharge current.

[0068] Figure 6 This is a schematic diagram of the components of an intelligent analysis platform: including a data receiving module 106-1 (such as a wireless network card or USB WiFi receiver), a storage management system 106-2 (such as a high-speed storage device SSD), 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, the storage management system 106-2 is connected to the data preprocessing module 106-3, and the data processing and analysis module 106-4 is connected to the real-time image generation module 106-5;

[0069] The data receiving module 106-1 receives WiFi data from an external network and connects to the host computer system via USB or Wi-Fi.

[0070] The storage management system 106-2 receives data from the data receiving module 106-1 via a network or high-speed interface, and stores and manages the data from the data receiving module 106-1.

[0071] The data preprocessing module 106-3 cleans, filters, and transforms the data to make it suitable for further analysis and processing.

[0072] 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 extract and transform the preload characteristic value of the rotating bolt.

[0073] The aforementioned monitoring device is used to perform ultrasonic monitoring of the preload of rotating bolts under high-temperature conditions. The working process may include:

[0074] First, a high-temperature adhesive (such as RgDg-SF series carbon fiber reinforced adhesive) is used to couple the magnetostrictive sheet onto the surface of the rotating bolt, and a high-temperature resistant and thermally stable coil-only sensor is formed by placing a coil-only EMAT detection probe around the rotating bolt.

[0075] In the subsequent initial stage, the FPGA module and the MOS isolated driver chip are connected in series, using the same timing control, and a weak low-voltage pulse trigger signal is input. The driver chip then increases the power of the trigger signal generated by the FPGA module, ensuring that the gate voltage of the MOS transistor can rise rapidly, thereby achieving rapid turn-on and turn-off of the MOS transistor. Simultaneously, the high-voltage capacitor discharge module performs transient charging and discharging of the capacitor bank under the switching control of the MOS transistor, generating a periodic, high-intensity excitation current. Utilizing the Lorentz force and magnetostrictive effect, this current excites alternating strong pulses in the coil, which in turn generate corresponding Lorentz forces and magnetostrictive strain in the magnetostrictive patch, driving the particles on the patch surface to vibrate, thereby generating active ultrasonic waves.

[0076] On the other hand, within the low-voltage capacitor discharge module, the charging and discharging is controlled by a switching module with a built-in IBGT, and its charging and discharging process takes a relatively long time. This module can generate a long-lasting and stable near-DC excitation current in the coil, providing a constant background magnetic field and magnetic induction intensity for ultrasonic echo detection.

[0077] The high-voltage capacitor discharge module and the low-voltage capacitor discharge module are connected in parallel and use independent timing control. The high-voltage capacitor discharge module is activated only when the DC-like component reaches its maximum, generating a strong pulse, which can greatly increase the excitation efficiency of ultrasound. The activation 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 activated when the DC-like current in the coil reaches its peak (i.e., when the magnetic field is strongest). This is designed to maximize the amplitude of the ultrasound excited by the magnetostrictive sheet.

[0078] Furthermore, the impedance matching module effectively ensures the highest partial voltage 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 the echo signal, including filtering and amplifying it.

[0079] Secondly, the 16-bit high-speed analog-to-digital converter acquires the analog signal from the coil-only EMAT detection probe and converts it into a digital signal using an FPGA; the data is then sent to external devices via a data transmission module.

[0080] Finally, the integrated platform receives and stores data from the detector, performs data analysis, extracts and processes preload characteristic values, and visualizes the monitoring data through a graphical interface, allowing users to intuitively view the current preload status and historical data of the rotating bolt.

[0081] In this embodiment of the application, the principle and formula involved in the extraction process of the preload characteristic value of the rotating bolt can be:

[0082] When a rotating bolt is subjected to preload, strain will occur within the bolt material. According to Hooke's Law, there is a linear relationship between stress and strain, meaning stress is directly proportional to strain. In this formula, the preload... elastic modulus of rotating bolt material and axial length variation This is relevant. Ultrasonic waves are high-frequency sound waves that can propagate through materials. When ultrasonic waves pass through a rotating bolt, their propagation speed is affected by the stress distribution within the material. An increase in preload alters the stress state of the material, thus changing the propagation speed of the ultrasonic waves. Specifically: in a rotating bolt, transverse waves can only propagate longitudinally, not laterally. The propagation speed of transverse waves is related to the shear modulus of the material. Longitudinal waves can propagate both longitudinally and laterally within the material. The propagation speed of longitudinal waves is related to the Young's modulus of the material. Because the preload affects the stress state of the material, the propagation speeds of both transverse and longitudinal waves change. By measuring the propagation time of these two waves in the rotating bolt, the change in axial length can be calculated, thereby estimating the preload.

[0083]

[0084]

[0085] in: It is the preload (N) of the rotating bolt. It is the elastic modulus (N / mm² or MPa) of the rotating bolt material. It is the cross-sectional area (mm²) of the rotating bolt, usually the product of π / 4 of the square of the rotating bolt diameter (d). This is the axial length variation (mm) of the rotating bolt, which is obtained by measuring the propagation time difference between the transverse and longitudinal waves. It is the natural length (mm) of the rotating bolt. The density of the rotating bolt material (unit: kg / m³) It is the time difference between the propagation of transverse and longitudinal waves (unit: s); This refers to the propagation speed of ultrasonic waves in the material of the rotating bolt (mm / μs). This value depends on the type of material and the temperature during testing. Typically, the longitudinal wave of the ultrasonic wave is chosen as the measurement object. Take the propagation speed of the longitudinal wave in the rotating bolt material.

[0086] The specific steps are as follows: First, find the elastic modulus E of the rotating bolt material and the propagation speed λ of the ultrasonic wave; then, without applying preload, measure the natural length of the rotating bolt. The process involves: 1) putting the rotating bolt into operation; 2) exciting and emitting transverse and longitudinal ultrasonic waves through the rotating bolt and measuring their propagation time within the bolt; 3) calculating the axial length change of the rotating bolt based on the propagation time difference between the transverse and longitudinal waves; and finally, calculating the preload using the aforementioned formula.

[0087] By accurately measuring the propagation time of ultrasonic waves, the change in axial length can be calculated with great precision, resulting in high accuracy in preload measurement. This method is applicable to various materials and types of rotating bolts, including those operating at high temperatures. During the use of rotating bolts, the change in preload can be monitored in real time by continuously measuring the propagation speed of ultrasonic waves.

[0088] The real-time image generation module 106-5 generates real-time images or visualizations based on the analysis results, so that users can intuitively understand and discover the data.

[0089] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A rotating bolt pre-tightening force monitoring device under high temperature conditions, characterized by, It comprises 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 with 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 coil of the coil-only EMAT detection probe is one of a racetrack coil, a spiral coil and a butterfly coil.

2. The monitoring device of claim 1, wherein, The multi-channel EMAT detection circuit comprises 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 connected in sequence; 3. The monitoring device of claim 1, wherein, The low-voltage capacitor discharge module, the impedance matching module and the echo detection module are electrically connected with the coil of the coil-only EMAT detection probe; The trigger module and the echo detection module are electrically connected with the signal processor. The multi-channel EMAT detection circuit further comprises a sampling current module, which is electrically connected with the impedance matching module.

4. The monitoring device of claim 3, wherein, 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 with the FPGA processing module.

5. The monitoring device of claim 1, wherein, The signal processor further comprises a data transmission module; the data transmission module is connected with the FPGA processing module.

6. The monitoring device of claim 5, wherein, The data transmission module adopts an ESP8266 WIFI module with a heat dissipation design.

7. The monitoring device of claim 6, wherein, The PCB of the signal processor is provided with a heat sink.

8. The monitoring device of claim 5, wherein, The heat sink adopts a single-wing or double-wing design.

9. The monitoring device of claim 8, wherein, It further comprises an intelligent analysis terminal platform, and the signal processor and the intelligent analysis terminal platform are wirelessly connected.

10. The monitoring device according to any one of claims 1 to 9, characterized in that, The coil of the coil-only EMAT detection probe is one of a racetrack coil, a spiral coil and a butterfly coil. The multi-channel EMAT detection circuit comprises 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 connected in sequence; The low-voltage capacitor discharge module, the impedance matching module and the echo detection module are electrically connected with the coil of the coil-only EMAT detection probe; The trigger module and the echo detection module are electrically connected with the signal processor. The multi-channel EMAT detection circuit further comprises a sampling current module, which is electrically connected with the impedance matching module. 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 with the FPGA processing module. The signal processor further comprises a data transmission module; the data transmission module is connected with the FPGA processing module. The data transmission module adopts an ESP8266 WIFI module with a heat dissipation design. The PCB of the signal processor is provided with a heat sink. The heat sink adopts a single-wing or double-wing design. It further comprises an intelligent analysis terminal platform, and the signal processor and the intelligent analysis terminal platform are wirelessly connected.

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