Ultrasonic guided wave online monitoring device and method for corrosion of offshore wind power jacket

Abstract

The invention provides an ultrasonic guided wave online monitoring device and method for corrosion of an offshore wind power jacket, and the method comprises the steps: generating four-channel excitation signals with a preset phase relation through a DSP signal processing and control system, and respectively driving four quadrants of a four-quadrant piezoelectric ceramic transducer array; the modal suppression sensor group monitors the propagated wave field; and the DSP signal processing and control system analyzes the signals, identifies a residual interference mode, adjusts excitation signal parameters of the four-quadrant piezoelectric ceramic transducer array, feeds back and controls in real time, and suppresses the interference mode to the lowest level. After the pure torsion wave is propagated along the jacket pipe and interacts with the corrosion defect, the four-quadrant piezoelectric ceramic transducer array collects a reflected echo signal. And the DSP signal processing and control system processes the collected echo signal, outputs a detection signal with a high signal-to-noise ratio, and evaluates the corrosion state of the jacket according to the signal. According to the invention, reliable and long-term on-line monitoring of the corrosion state of the jacket is realized.

Description

Technical Field

[0001] This invention relates to the field of marine engineering structure health monitoring technology, and more specifically, to an ultrasonic guided wave online monitoring device and method for corrosion of offshore wind turbine jackets. Background Technology

[0002] Offshore wind turbine jackets, as critical infrastructure supporting wind turbine generators, operate in harsh marine environments for extended periods and face severe corrosion challenges. Corrosion weakens the structure's load-bearing capacity and can lead to catastrophic accidents in severe cases. Therefore, long-term and effective online monitoring of the jacket structure, especially the underwater portion, is crucial.

[0003] Guided Ultrasonic Testing (GWUT) technology has been applied in pipeline inspection due to its advantages such as long propagation distance and rapid structural screening. However, applying it to geometries with complex structures like jacket supports presents significant challenges: (1) Complex signals and aliasing: In the tubular components of the catheter framework, ultrasonic guided waves exist in multiple modes (such as torsional waves, longitudinal waves, and bending waves), and most modes have dispersive characteristics, that is, the propagation speed changes with frequency, resulting in wave packet broadening and signal distortion. Ideally, exciting pure non-dispersive modes (such as T(0,1) torsional waves) is the key to achieving long-distance, high signal-to-noise ratio detection. However, due to the non-ideal nature of the excitation method or the asymmetry of the structure, conventional transducers are prone to simultaneously exciting multiple modes, especially bending wave modes. These unnecessary modes will alias with the effective echo signal from the defect, seriously interfering with signal interpretation and reducing the reliability of detection.

[0004] (2) Severe geometric interference: The complex geometric features of the jacket, such as welds, nodes, and branch pipe connections, will cause strong guided wave reflection, scattering and mode conversion, forming a large amount of structural noise. This noise can easily mask the weak echo signals generated by defects such as corrosion (especially early corrosion).

[0005] (3) Environmental factors have a great impact: factors such as anti-corrosion coatings, marine organisms, and temperature changes in the marine environment can all affect the propagation characteristics of guided waves, making it difficult to obtain stable signals and analyze them accurately.

[0006] Therefore, addressing the issues of low waveguide mode purity and poor signal-to-noise ratio is a core challenge in existing technologies for online monitoring of jacket corrosion. There is an urgent need for an online monitoring technology capable of actively controlling waveguide modes, suppressing interference signals, and adapting to harsh marine environments. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an ultrasonic guided wave online monitoring device and method for corrosion of offshore wind turbine jackets. This solution aims to achieve high-purity single guided wave mode excitation through innovative sensor array layout, mode suppression technology, and a precise signal control system, effectively suppressing interference modes and significantly improving the signal-to-noise ratio and detection accuracy. This addresses the problems of difficult signal interpretation and low detection reliability in the complex structure of jackets in existing technologies, enabling reliable, long-term online monitoring of jacket corrosion status.

[0008] Specific technical content of the present invention: An ultrasonic guided wave online monitoring device for corrosion of offshore wind turbine jackets includes a four-quadrant piezoelectric ceramic transducer array, a dual-sensor mode suppression unit, and a DSP signal processing and control system. The four-quadrant piezoelectric ceramic transducer array consists of multiple piezoelectric ceramic (PZT) elements, which are evenly distributed along the circumference of the conduit pipe and divided into four independent quadrants, each containing one or more PZT elements.

[0009] This array can be used as an exciter to emit ultrasonic guided waves and as a receiver to receive echo signals. Its four-quadrant layout is the basis for achieving selective excitation of specific guided wave modes.

[0010] The dual-sensor modal suppression unit consists of a modal suppression sensor. This sensor group can be an additional ring of sensors set outside the four-quadrant piezoelectric ceramic transducer array, or it can be a reuse of some PZT elements in the four-quadrant piezoelectric ceramic transducer array and given specific receiving and processing functions.

[0011] The modal suppression sensor array is positioned axially at a predetermined distance L from the excitation center of the four-quadrant piezoelectric ceramic transducer array. Its core function is to monitor the wave field emitted from the excitation source in real time, particularly identifying unwanted interference modes, such as bending waves.

[0012] The core of a DSP signal processing and control system is one or more digital signal processors (DSPs), which are responsible for: (1) Excitation signal generation and precise control: The DSP can generate multi-channel excitation signals with precise controllable phase and amplitude. In order to excite a pure T(0,1) torsional wave, the DSP will output excitation signals with specific phase relationships (such as 0°, 90°, 180°, 270°) to the four-quadrant transducers respectively, and maximize the energy of the torsional wave by utilizing the principle of wave interference and construction, while suppressing other modes.

[0013] (2) Execution of the mode suppression algorithm: The DSP receives and processes signals from the mode suppression sensor group in real time. By analyzing the amplitude and phase differences of the signals received by the sensors at different locations, the DSP can determine the existence and characteristics of interference modes such as bending waves. Subsequently, the DSP executes the mode suppression algorithm, which generates a "compensation wave field" with the opposite phase to the interference mode by adjusting the excitation signal to the four-quadrant transducer array (e.g., fine-tuning the amplitude and phase of each quadrant), thereby actively canceling or suppressing the interference mode.

[0014] (3) Echo signal processing and analysis: After completing modal excitation and suppression, the DSP acquires and processes the echo signal received by the four-quadrant piezoelectric ceramic transducer array, which mainly contains pure torsional wave modes. The processing includes digital filtering, signal accumulation and averaging, envelope detection, etc., to further improve the signal-to-noise ratio.

[0015] (4) Corrosion status assessment: The processed "clean" signal is sent to the upper-level analysis software or embedded algorithm. By analyzing the signal characteristics (such as the appearance of echoes at specific locations, changes in the attenuation of background signals, etc.) and comparing them with the reference signal, the location and approximate severity of corrosion defects are determined.

[0016] An ultrasonic guided wave online monitoring device and method for corrosion of offshore wind turbine jacket structures, the steps of which are as follows: S1. Excitation and Modal Control: The DSP signal processing and control system generates four-channel excitation signals with preset phase relationships, which drive the four quadrants of the four-quadrant piezoelectric ceramic transducer array to mainly excite T(0,1) torsional waves.

[0017] S2. Interference Mode Monitoring and Suppression: Simultaneously, the mode suppression sensor array monitors the propagating wave field in real time. The DSP signal processing and control system analyzes the signal and identifies residual bending waves and other interference modes. The DSP signal processing and control system immediately adjusts the excitation signal parameters of the four-quadrant piezoelectric ceramic transducer array, performing real-time feedback control to suppress the interference modes to the lowest possible level.

[0018] S3. Defect Echo Acquisition: After the pure torsional wave propagates along the guide frame pipe and interacts with the corrosion defects, a four-quadrant piezoelectric ceramic transducer array acts as a receiver to acquire the reflected echo signal.

[0019] S4. Signal Processing and Evaluation: The DSP signal processing and control system performs noise reduction and enhancement on the acquired echo signals, ultimately outputting a detection signal with a high signal-to-noise ratio. The data analysis unit evaluates the corrosion status of the guide frame based on this signal.

[0020] Compared with the prior art, the beneficial effects of the present invention are: High-purity single-guided wave mode excitation: Through the four-quadrant transducer array layout and the precise multi-channel phase control of the DSP, it is possible to selectively excite energy-concentrated, non-dispersive T(0,1) torsional wave modes, ensuring the purity of the signal from the source and greatly simplifying the subsequent signal processing and interpretation.

[0021] Actively suppressing interference modes significantly improves the signal-to-noise ratio: The unique dual-sensor mode suppression technology, through real-time monitoring and feedback control, can actively and effectively cancel interference modes such as bending waves caused by various non-ideal factors. This solves the core problems of strong structural noise and severe mode aliasing in existing technologies, allowing weak corrosion defect signals to be highlighted, thereby significantly improving the signal-to-noise ratio and detection sensitivity.

[0022] High detection accuracy and reliability: Due to the acquisition of pure modal signals with extremely high signal-to-noise ratio, the present invention can more accurately identify and locate corrosion defects, especially suitable for the detection of early micro-corrosion, thus improving the overall reliability and early warning capability of the online monitoring system.

[0023] Suitable for long-term online monitoring: The entire system is based on DSP to achieve automated control and processing. Combined with a robustly packaged PZT array, it can adapt to harsh marine environments and achieve long-term, unattended online monitoring of the corrosion status of the jacket structure. Attached Figure Description

[0024] Figure 1 This is a diagram showing the overall system architecture of the device of the present invention; Figure 2 This is a schematic diagram of the layout of a four-quadrant piezoelectric ceramic transducer array on the tube wall of a guide frame. Figure 3 This is one of the schematic diagrams illustrating the working principle of the dual-sensor mode suppression unit; Figure 4 This is the second schematic diagram illustrating the working principle of the dual-sensor modal suppression unit. Detailed Implementation

[0025] The core of the ultrasonic guided wave online monitoring device for corrosion of offshore wind turbine jacket provided by this invention lies in a collaborative working system consisting of a four-quadrant piezoelectric ceramic transducer array, a dual-sensor mode suppression unit, and a DSP signal processing and control system.

[0026] The present invention will now be described in detail with reference to the accompanying drawings: Please see Figures 1 to 4 The present invention relates to an ultrasonic guided wave online monitoring device for corrosion of offshore wind turbine jackets, comprising a four-quadrant piezoelectric ceramic transducer array 100, a dual-sensor mode suppression unit, and a DSP signal processing and control system. The four-quadrant piezoelectric ceramic transducer array 100 is composed of multiple piezoelectric ceramic PZT elements, evenly distributed along the circumference of the conduit frame tube 10, and divided into four independent quadrants: 110a, 110b, 110c, and 110d, as shown below. Figure 2 As shown. Each quadrant contains one or more PZT elements.

[0027] This array can be used as an exciter to emit ultrasonic guided waves and as a receiver to receive echo signals. Its four-quadrant layout is the basis for achieving selective excitation of specific guided wave modes.

[0028] The dual-sensor mode suppression unit consists of a mode suppression sensor group. This sensor group can be an additional ring of sensors set outside the four-quadrant piezoelectric ceramic transducer array 100, or it can be a partial reuse of PZT elements in the four-quadrant piezoelectric ceramic transducer array 100 with specific receiving and processing functions.

[0029] like Figure 3 and Figure 4 As shown, the mode suppression sensor group is positioned axially at a preset distance L from the excitation center of the four-quadrant piezoelectric ceramic transducer array 100. Its core function is to monitor the wave field emitted from the excitation source in real time, especially to identify unwanted interference modes, such as bending waves.

[0030] The core of a DSP signal processing and control system is one or more digital signal processors (DSPs); this system is responsible for: (1) Excitation signal generation and precise control: The DSP can generate multi-channel excitation signals with precise controllable phase and amplitude. In order to excite a pure T(0,1) torsional wave, the DSP will output excitation signals with specific phase relationships (such as 0°, 90°, 180°, 270°) to the four-quadrant transducers 110a-110d respectively, and maximize the energy of the torsional wave by utilizing the principle of wave interference and construction, while suppressing other modes.

[0031] (2) Execution of the mode suppression algorithm: The DSP receives and processes signals from the mode suppression sensor group in real time. By analyzing the amplitude and phase differences of the signals received by the sensors at different locations, the DSP can determine the existence and characteristics of interference modes such as bending waves. Subsequently, the DSP executes the mode suppression algorithm, and by adjusting the excitation signal to the four-quadrant transducer array 100 (e.g., fine-tuning the amplitude and phase of each quadrant), it generates a "compensation wave field" with the opposite phase to the interference mode, thereby actively canceling or suppressing the interference mode.

[0032] (3) Echo signal processing and analysis: After completing modal excitation and suppression, the DSP acquires and processes the echo signal received by the four-quadrant piezoelectric ceramic transducer array 100, which mainly contains pure torsional wave modes. The processing includes digital filtering, signal accumulation averaging, envelope detection, etc., to further improve the signal-to-noise ratio.

[0033] (4) Corrosion status assessment: The processed "clean" signal is sent to the upper-level analysis software or embedded algorithm. By analyzing the signal characteristics (such as the appearance of echoes at specific locations, changes in the attenuation of background signals, etc.) and comparing them with the reference signal, the location and approximate severity of corrosion defects are determined.

[0034] An ultrasonic guided wave online monitoring device and method for corrosion of offshore wind turbine jacket structures, the steps of which are as follows: S1. Excitation and Modal Control: The DSP signal processing and control system generates four-channel excitation signals with preset phase relationships, which drive the four quadrants of the four-quadrant piezoelectric ceramic transducer array 100 respectively to mainly excite T(0,1) torsional waves.

[0035] S2. Interference Mode Monitoring and Suppression: Simultaneously, the mode suppression sensor group monitors the propagating wave field in real time. The DSP signal processing and control system analyzes the signal and identifies residual bending waves and other interference modes. The DSP signal processing and control system immediately adjusts the excitation signal parameters of the four-quadrant piezoelectric ceramic transducer array 100, performing real-time feedback control to suppress the interference modes to the lowest level.

[0036] S3. Defect Echo Acquisition: After the pure torsional wave propagates along the guide pipe and interacts with the corrosion defects, the four-quadrant piezoelectric ceramic transducer array 100 acts as a receiver to acquire the reflected echo signal.

[0037] S4. Signal Processing and Evaluation: The DSP signal processing and control system performs noise reduction and enhancement on the acquired echo signals, ultimately outputting a detection signal with a high signal-to-noise ratio. The data analysis unit evaluates the corrosion status of the guide frame based on this signal.

[0038] The specific operation process of this embodiment is as follows: 1. An array of piezoelectric ceramic transducers, divided into at least four independent quadrants along the circumference, is arranged on the tubular component of the jacket structure. 2. A multi-channel excitation signal with a preset phase relationship is generated by a digital signal processing system and applied to at least four quadrants of the transducer array to selectively excite a preset single waveguide mode; the preset single waveguide mode is a T(0,1) torsional wave mode.

[0039] 3. The wave field propagating from the transducer array is monitored in real time by a mode suppression sensor group to identify unwanted interference guided wave modes; the interference guided wave modes are bending wave modes. The mode suppression sensor group is set independently of the piezoelectric ceramic transducer array and maintains a preset distance from the excitation center of the transducer array along the axial direction of the tubular component.

[0040] 4. The digital signal processing system adjusts the excitation signal applied to the transducer array in real time based on the monitoring signal of the mode suppression sensor group to suppress the interfering guided wave mode; the steps of the digital signal processing system to adjust the excitation signal include: adjusting the phase and / or amplitude of the excitation signal applied to each quadrant of the transducer array to generate a compensation wave field that cancels out the interfering guided wave mode.

[0041] 5. Use a transducer array to receive the echo signal that propagates through and returns from the tubular component, and assess the corrosion status of the tubular component based on the echo signal.

[0042] The modal suppression sensor group of the present invention can be more than one set, and multiple sets can be arranged along the axial direction to adapt to the suppression requirements of different frequencies or more complex interference modes.

[0043] The DSP signal processing and control system of the present invention can integrate advanced AI algorithms to more intelligently optimize mode suppression parameters or perform pattern recognition and quantitative evaluation of the final defect signal.

[0044] The transducer array of the present invention can be designed with a flexible substrate to better fit the irregularities of the guide frame surface.

Claims

1. An on-line monitoring device for corrosion of offshore wind turbine jacket by ultrasonic guided waves, characterized in that, It comprises a four-quadrant piezoelectric ceramic transducer array, a dual-sensor group mode suppression unit and a DSP signal processing and control system. The four-quadrant piezoelectric ceramic transducer array is composed of multiple piezoelectric ceramic PZT elements, is uniformly distributed along the circumferential direction of the pipe rack pipe material, and is divided into four independent quadrants, each of which contains one or more PZT elements; the four-quadrant piezoelectric ceramic transducer array is used as an exciter to emit ultrasonic guided waves, and can also be used as a receiver to receive echo signals; The dual-sensor group mode suppression unit comprises a mode suppression sensor group; the mode suppression sensor group is at a preset distance L from the excitation center of the four-quadrant piezoelectric ceramic transducer array in the axial direction, and is used to monitor the wave field emitted from the excitation source in real time; The DSP signal processing and control system comprises one or more digital signal processors DSP, which is used for: (1) Excitation signal generation and accurate control: the DSP can generate multi-channel, phase and amplitude accurately controllable excitation signals; in order to excite pure T(0,1) torsional waves, the DSP outputs excitation signals with phase relationship to the four-quadrant piezoelectric ceramic transducer array, and uses the interference principle of waves to maximize the torsional wave energy and suppress the interference mode; (2) Mode suppression algorithm execution: the DSP receives and processes signals from the mode suppression sensor group in real time; by analyzing the signal amplitude and phase difference received by the sensor group at different positions, the DSP can determine the existence and characteristics of the interference mode; immediately, the DSP executes the mode suppression algorithm, and generates a "compensation wave field" with opposite phase to the interference mode by adjusting the excitation signal to the four-quadrant transducer array, thereby actively canceling or suppressing the interference mode; (3) Echo signal processing and analysis: after completing the mode excitation and suppression, the DSP collects and processes the echo signals received by the four-quadrant piezoelectric ceramic transducer array, which mainly contains pure torsional wave mode; and processes to improve the signal-to-noise ratio; (4) Corrosion state evaluation: the "clean" signal after processing is sent to the upper analysis software or embedded algorithm, and the position and approximate severity of the corrosion defect are determined by comparing the signal characteristics with the reference signal.

2. The device for on-line monitoring of corrosion in offshore wind turbine jacket by ultrasonic guided waves according to claim 1, characterized in that, The mode suppression sensor group is a circle of sensors additionally arranged outside the four-quadrant piezoelectric ceramic transducer array, or is part of the PZT elements in the four-quadrant piezoelectric ceramic transducer array which is multiplexed and given the functions of receiving and processing.

3. An apparatus and method for on-line monitoring of corrosion of offshore wind turbine jacket by ultrasonic guided waves, characterized in that, The method steps of the offshore wind power pipe rack corrosion ultrasonic guided wave online monitoring device of claim 1 or 2 are as follows: S1. Excitation and mode control: the DSP signal processing and control system generates four-channel excitation signals with a preset phase relationship, and drives the four quadrants of the four-quadrant piezoelectric ceramic transducer array to mainly excite T(0,1) torsional waves; S2. Interference mode monitoring and suppression: The modal suppression sensor group monitors the propagating wave field in real time; the DSP signal processing and control system analyzes its signals and identifies the residual interference mode; the DSP signal processing and control system immediately adjusts the excitation signal parameters of the four-quadrant piezoelectric ceramic transducer array for real-time feedback control to suppress the interference mode to the lowest level; S3. Defect echo acquisition: After the pure torsional wave propagates along the pipe material of the jacket and interacts with the corrosion defect, the four-quadrant piezoelectric ceramic transducer array acts as a receiver to collect the reflected echo signals; S4. Signal processing and evaluation: The DSP signal processing and control system performs noise reduction and enhancement processing on the collected echo signals, and finally outputs high signal-to-noise ratio detection signals; the data analysis unit evaluates the corrosion state of the jacket according to the signals.

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