A hydrogen pipeline damage state detection system and method based on nonlinear ultrasound

Abstract

This invention provides a hydrogen pipeline damage state detection system and method based on nonlinear ultrasound. The system's nonlinear ultrasonic detection device includes a signal excitation module and a waveform receiving module. The signal excitation module uses pulsed ultrasonic signals to ultrasonically excite the test sample, achieving non-contact ultrasonic propagation to acquire the vibration signal of the detection response. The waveform receiving module analyzes the nonlinear response waveform information. The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information. The evaluation matrix formulation module establishes hydrogen damage identification criteria based on the correlation between state feature parameters and hydrogen damage status. Furthermore, the hydrogen damage assessment module comprehensively evaluates and provides early warning of the pipeline's hydrogen damage status based on the hydrogen damage identification matrix combined with the state feature parameters of the detection response. This approach overcomes the limitations of existing technologies in terms of application scenarios and accuracy, providing a comprehensive and reliable evaluation of hydrogen damage status.

Description

Technical Field

[0001] This invention relates to the field of non-destructive testing technology for hydrogen damage in hydrogen pipelines, and particularly to a system and method for detecting the damage status of hydrogen pipelines based on nonlinear ultrasound. Background Technology

[0002] Hydrogen-contaminated equipment operates under ultra-high pressure, low temperature, and cyclical pressure fluctuations for extended periods, exacerbating hydrogen-induced damage and deterioration of materials. Hydrogen ingress into materials easily leads to a decline in mechanical properties, manifesting microscopically as hydrogen blistering and hydrogen cracking. Early-stage damage is extremely small and difficult to detect through routine inspections. If it progresses to later stages, it can easily cause delayed fracture, increasing the likelihood of pipe failure and posing a significant challenge to equipment safety during hydrogen storage and transportation. Given that hydrogen damage readily causes delayed fracture in metallic materials, occurring suddenly and unpredictably with severe consequences, detecting the extent of hydrogen damage in its early stages is of paramount importance.

[0003] Based on whether the detection method damages the object being tested or affects its performance, existing hydrogen damage detection methods can be divided into two main categories: destructive testing and non-destructive testing (i.e., non-destructive testing methods). Among them, ultrasonic non-destructive testing technology is widely used in the field of industrial testing due to its many advantages, such as speed, portability, ease of operation, and applicability to in-service facilities.

[0004] Existing ultrasonic nondestructive testing for hydrogen damage is generally a contact test, which requires applying a coupling agent to the surface of the test piece. This not only makes it difficult to apply to high-temperature environments but also makes it unsuitable for testing complex workpieces, greatly limiting the applicability of ultrasonic testing. Furthermore, contact testing methods are mainly based on traditional linear ultrasound, which uses indicators such as ultrasonic velocity and attenuation for characterization. These methods are easily affected by environmental factors and surface conditions, and are not sensitive to defects such as microcracks much smaller than the wavelength and degradation of material mechanical properties, making it difficult to detect early hydrogen damage. In addition, ultrasonic evaluation methods based on single parameters are not suitable for complex material microstructures and the requirements for characterization accuracy, making it difficult to comprehensively characterize material damage information and susceptible to environmental noise and other factors.

[0005] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a hydrogen pipeline damage status detection system based on nonlinear ultrasound. This system overcomes the limitations of existing technologies in terms of application scenarios and accuracy, providing a comprehensive and reliable evaluation of hydrogen damage status. The system calculates state characteristic parameters based on nonlinear response waveform information; establishes hydrogen damage identification criteria based on the correlation between state characteristic parameters and hydrogen damage status; and then comprehensively assesses and provides early warning of pipeline hydrogen damage status based on the hydrogen damage identification matrix combined with the state characteristic parameters of the detection response of the hydrogen pipeline under test. Preferably, in one embodiment, the system includes: a nonlinear ultrasonic detection device, a characteristic parameter calculation module, an evaluation matrix formulation module, and a hydrogen damage assessment module.

[0007] The nonlinear ultrasonic testing device includes a signal excitation module and a waveform receiving module;

[0008] The signal excitation module is configured to excite the test sample with high-energy pulsed ultrasonic signals to achieve non-contact ultrasonic propagation and obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0009] The waveform receiving module is configured to analyze the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0010] The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0011] The evaluation matrix formulation module is connected to the feature parameter calculation module and is configured to establish a hydrogen damage identification criterion based on the correlation between the state feature parameters and the hydrogen damage status.

[0012] The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level of the hydrogen pipeline based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

[0013] Optionally, in one embodiment, in the nonlinear ultrasonic testing device, the signal excitation module is equipped with a signal generator as a signal source, which outputs a waveform of a set form to realize the transmission of high-energy pulses.

[0014] Furthermore, in one embodiment, the signal excitation module is equipped with a transmitting transducer, which uses the inverse piezoelectric effect to convert an electrical signal into a vibration signal and transmit it to the test sample, thereby realizing non-contact ultrasonic excitation and performing non-contact detection.

[0015] Preferably, in one embodiment, the signal excitation module further includes a filter connected between the signal generator and the transmitting transducer, configured to filter the signal transmitted to the transmitting transducer to eliminate interference from system nonlinearity.

[0016] In one embodiment, the waveform receiving module includes a receiving transducer and an oscilloscope;

[0017] The receiving transducer uses the piezoelectric effect to convert the test response vibration signal of the sample into an electrical signal, which is then transmitted to an oscilloscope. The oscilloscope then displays the test response electrical signal as waveform information.

[0018] In one optional embodiment, the signal excitation module and the receiving transducer are respectively installed at corresponding positions on the scanning bracket, and one side of the oscilloscope is connected to the receiving transducer, while the other side is connected to the computer system.

[0019] Furthermore, in one embodiment, the signal excitation module includes two transmitting transducers, which are symmetrically distributed on both sides of the receiving transducer on the scanning bracket.

[0020] In a preferred embodiment, the feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0021] The feature parameter calculation module calculates the nonlinear coefficients and harmonic energy based on the time-domain and frequency-domain information of the nonlinear response waveform information.

[0022] The nonlinear coefficients are calculated as follows:

[0023] After the received ultrasonic signal is denoised and filtered, a fast Fourier transform is performed to obtain the spectrum information. The nonlinear coefficient is calculated based on the amplitude of the fundamental frequency signal and the amplitude of the second harmonic signal corresponding to the spectrum information.

[0024] Calculate harmonic energy using the following steps:

[0025] The intensity of the nonlinear time-domain response is characterized by calculating the energy magnitude of harmonics in the time-domain signal as a harmonic energy characteristic parameter.

[0026] Preferably, in one embodiment, the feature parameter calculation module calculates the nonlinear coefficient β using the following formula:

[0027]

[0028] In the formula, x is the propagation distance of the wave, k is the wave number, A1 is the amplitude of the fundamental frequency signal, and A2 is the amplitude of the second harmonic signal.

[0029] In an optional embodiment, the feature parameter calculation module is further configured to normalize the nonlinear coefficients, mapping the nonlinear coefficients to a set range to obtain relative nonlinear coefficients, which serve as the final nonlinear feature parameters for evaluating frequency domain features.

[0030] Furthermore, in one embodiment, the feature parameter calculation module is configured to extract the envelope of the time-domain signal using the Hilbert-Huang transform, and to take the modulus value of the signal to determine the upper and lower envelopes at the corresponding second harmonic frequencies, and to calculate the average value of the two as the harmonic energy feature parameter.

[0031] In a preferred embodiment, the feature parameter calculation module is further configured to normalize the harmonic energy, map the harmonic energy to a set range to obtain the relative harmonic energy, which serves as the final harmonic energy feature parameter for evaluating the time-domain energy characteristics.

[0032] Furthermore, in one embodiment, the evaluation matrix formulation module is configured to, for the nonlinear coefficient characteristic parameter, use the change value Δβ between the maximum and minimum values ​​of each damage degree as the discrimination limit for classifying hydrogen damage, selecting 0.2Δβ and 0.7Δβ as critical points, corresponding to three levels; for the harmonic energy characteristic parameter, use the change value ΔE between the maximum and minimum values ​​of each damage degree. m 0.2ΔE was chosen as the discrimination limit for classifying hydrogen damage. m and 0.7△E m As a critical point, it is divided into 3 levels.

[0033] In an optional embodiment, the signal generator outputs a sinusoidal pulse train signal modulated by a Hanning window function. The signal modulated by the window function reduces spectral leakage and provides more concentrated ultrasonic energy.

[0034] On the other hand, in a preferred embodiment, the system further includes a system calibration unit configured to verify whether the signal received by the oscilloscope meets the time requirements and theoretical position requirements of the primary reflected wave signal of the ultrasonic transducer.

[0035] Furthermore, in one embodiment, the system calibration unit is also configured to verify whether the distribution of the fundamental frequency signal and the second harmonic signal of the signal received by the oscilloscope meets the set requirements.

[0036] Based on the application aspects of the methods described in any one or more of the above embodiments, the present invention also provides a method for detecting the damage state of hydrogen pipelines based on nonlinear ultrasound. This method is applied to a system performing any one or more of the above embodiments, and the method includes:

[0037] The test sample is ultrasonically excited by a signal excitation module based on a high-energy pulsed ultrasonic signal, thereby achieving non-contact ultrasonic propagation to obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0038] The waveform receiving module analyzes the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0039] The characteristic parameter calculation module calculates state characteristic parameters, including nonlinear coefficients and harmonic energy, based on the nonlinear response waveform information.

[0040] Using the evaluation matrix formulation module, hydrogen damage identification criteria are established based on the correlation between the state characteristic parameters and the hydrogen damage status.

[0041] Based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test, a comprehensive assessment and early warning of the hydrogen damage level of the hydrogen pipeline is performed.

[0042] Based on other aspects of the methods described in the above embodiments, the present invention also provides a storage medium storing program code capable of implementing the methods described in the above embodiments.

[0043] Compared with the closest prior art, the present invention also has the following beneficial effects:

[0044] This invention provides a hydrogen pipeline damage state detection system and method based on nonlinear ultrasound. The system includes a nonlinear ultrasonic detection device comprising a signal excitation module and a waveform receiving module. The signal excitation module uses high-energy pulsed ultrasonic signals to ultrasonically excite the test sample, achieving non-contact ultrasonic propagation to acquire the vibration signal of the detection response. The waveform receiving module analyzes the nonlinear response waveform information of the sample. The detection structure is laid out according to the shape characteristics of the hydrogen pipeline, enabling non-contact detection, avoiding interference with the operation process, and improving the detection coverage and efficiency.

[0045] The feature parameter calculation module is configured to calculate state feature parameters based on nonlinear response waveform information; the evaluation matrix formulation module is configured to establish hydrogen damage identification criteria based on the correlation between the state feature parameters and hydrogen damage status; then, the hydrogen damage assessment module comprehensively evaluates and provides early warning of hydrogen damage status of the hydrogen pipeline based on the hydrogen damage identification matrix and the state feature parameters of the detection response of the hydrogen pipeline under test. Nonlinear information is extracted from the time and frequency domains for comprehensive characterization, and time and frequency domain feature parameters are extracted separately. Joint characterization is performed based on harmonic energy and nonlinear coefficients, effectively improving the problem of incomplete information from a single ultrasonic response parameter. Furthermore, this scheme can identify early hydrogen damage in in-service hydrogen-related equipment, enabling timely preventative maintenance to prevent irreversible damage. When the damage reaches a certain level, an audible and visual alarm is triggered, reducing manual inspection costs. Moreover, the system of this invention has a simple structure, is easy to install, and has reliable performance.

[0046] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0047] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0048] Figure 1 This is a schematic diagram of the structure of a hydrogen pipeline damage state detection system based on nonlinear ultrasound provided in an embodiment of the present invention;

[0049] Figure 2 This is a schematic diagram of the detection process when the hydrogen pipeline damage state detection system based on nonlinear ultrasound provided in the embodiment of the present invention is applied.

[0050] Figure 3 This is an example diagram illustrating the hydrogen damage severity classification criteria when the hydrogen pipeline damage status detection system based on nonlinear ultrasound provided in this embodiment of the invention is applied.

[0051] Figure 4 This is a schematic diagram of the online detection program principle of the hydrogen pipeline damage state detection system based on nonlinear ultrasound provided in the embodiments of the present invention;

[0052] Figure 5 This is a schematic diagram of the structural setup of a hydrogen pipeline damage state detection system based on nonlinear ultrasound provided in another embodiment of the present invention;

[0053] Figure 6This is a schematic diagram of the arrangement of transmitting and receiving transducers in the hydrogen pipeline damage status monitoring system based on nonlinear ultrasound provided in this embodiment of the invention.

[0054] Figure 7 This is a schematic diagram of the transducer arrangement of the hydrogen process pipeline in the hydrogen refueling station of the hydrogen pipeline damage state detection system based on nonlinear ultrasound provided in this embodiment of the invention.

[0055] Figure 8 This is a flowchart illustrating the hydrogen pipeline damage state detection method based on nonlinear ultrasound provided in another embodiment of the present invention.

[0056] In the attached diagram, 1 is a signal generator; 2 is a low-pass filter; 3 is a transmitting transducer; 4 is a receiving transducer; 5 is an oscilloscope; and 6 is a computer. Detailed Implementation

[0057] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples. Those skilled in the art will then fully understand how the present invention uses technical means to solve technical problems and achieve technical effects, and will be able to implement the present invention specifically based on the above-described implementation process. It should be noted that, as long as there is no conflict, the various embodiments and features of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0058] Although the flowchart describes the operations as sequential processes, many of these operations can be performed in parallel, concurrently, or simultaneously. The order of the operations can be rearranged. A process can terminate when its operation is complete, but it may also have additional steps not included in the diagram. A process can correspond to a method, function, procedure, subroutine, subroutine, etc.

[0059] Computer equipment includes user equipment and network equipment. User equipment or clients include, but are not limited to, computers, smartphones, and PDAs (Personal Digital Assistants). Network equipment includes, but is not limited to, single network servers, server groups consisting of multiple network servers, or cloud computing devices composed of a large number of computers or network servers. These devices can operate independently to implement the present invention, or they can connect to a network and interact with other computer devices within the network to implement the present invention. The networks in which the computer equipment resides include, but are not limited to, the Internet, wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), and VPN networks.

[0060] The terms “first,” “second,” etc., may be used herein to describe various units, but these units should not be limited by these terms; they are used merely to distinguish one unit from another. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. When a unit is referred to as “connected” or “coupled” to another unit, it may be directly connected or coupled to said other unit, or there may be intermediate units present.

[0061] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0062] Hydrogen-contaminated equipment operates under ultra-high pressure, low temperature, and cyclical pressure fluctuations for extended periods, exacerbating hydrogen-induced damage and deterioration of materials. Hydrogen ingress into materials easily leads to a decrease in mechanical properties, manifesting microscopically as hydrogen blistering and hydrogen cracking. Early-stage damage is extremely small and difficult to detect through routine inspections. If it progresses to later stages, it can easily cause delayed fracture, increasing the likelihood of pipe failure and posing a significant challenge to equipment safety during hydrogen storage and transportation.

[0063] Hydrogen gas causes damage to metallic materials in various forms, such as hydrogen embrittlement, hydrogen blistering, and hydrogen-induced cracking. Considering that hydrogen damage easily leads to delayed fracture of metallic materials, and that its occurrence is sudden, unpredictable, and with serious consequences, it is crucial to detect the extent of hydrogen damage in its early stages. Based on whether the detection method damages the object being tested or affects its performance, existing hydrogen damage detection methods can be divided into two main categories: destructive testing and non-destructive testing (i.e., non-destructive testing methods). Among these, ultrasonic non-destructive testing technology is widely used in industrial testing due to its numerous advantages, including speed, portability, ease of operation, and applicability to in-service facilities.

[0064] Existing ultrasonic nondestructive testing for hydrogen damage is generally a contact test, which requires applying a coupling agent to the surface of the test piece. This not only makes it difficult to apply to high-temperature environments but also makes it unsuitable for testing complex workpieces, greatly limiting the applicability of ultrasonic testing. Furthermore, contact testing methods are mainly based on traditional linear ultrasound, which uses indicators such as ultrasonic velocity and attenuation for characterization. These methods are easily affected by environmental factors and surface conditions, and are not sensitive to defects such as microcracks much smaller than the wavelength and degradation of material mechanical properties, making it difficult to detect early hydrogen damage. In addition, ultrasonic evaluation methods based on single parameters are not suitable for complex material microstructures and the requirements for characterization accuracy, making it difficult to comprehensively characterize material damage information and susceptible to environmental noise and other factors.

[0065] To address the shortcomings of existing ultrasonic testing technologies and ensure the safety of hydrogen pipelines and equipment, a non-contact ultrasonic testing method is proposed. This method records the occurrence and evolution of hydrogen damage in real time and enables online detection and assessment of early hydrogen damage in hydrogen pipelines. The invention proposes an online detection and assessment method for hydrogen damage in hydrogen pipelines based on non-linear ultrasonic testing technology. It utilizes an air-coupled transducer to achieve non-contact transmission and reception of ultrasonic waves. A transducer layout strategy is designed for hydrogen pipelines, employing a "two-transmitter, one-receiver" layout to improve detection coverage. The hydrogen damage level is comprehensively and intuitively evaluated using two time-domain characteristic parameters (non-linear coefficient and harmonic energy) and a frequency-domain characteristic parameter. A hydrogen damage alarm system is established to achieve online detection and early warning.

[0066] The purpose of this invention is to provide a non-destructive testing method to ensure the structural integrity of hydrogen pipelines. It utilizes the high sensitivity of nonlinear ultrasonic testing, integrates time-domain and frequency-domain characteristics to evaluate the intensity of hydrogen damage, proposes a non-contact online testing method, and realizes comprehensive assessment and early warning of hydrogen damage levels.

[0067] The structural components, connection methods, and functional principles of the system according to embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Although the logical order of each operation is shown in the description of the system's structural operation, in some cases, the operations shown or described may be performed in a different order than that shown here.

[0068] Example 1

[0069] Figure 1 This diagram illustrates the structure of a hydrogen pipeline damage detection system based on nonlinear ultrasound according to Embodiment 1 of the present invention. (Refer to...) Figure 1 It can be seen that the system includes: a nonlinear ultrasonic detection device, a characteristic parameter calculation module, an evaluation matrix formulation module, and a hydrogen damage assessment module;

[0070] The nonlinear ultrasonic testing device includes a signal excitation module and a waveform receiving module;

[0071] The signal excitation module is configured to excite the test sample based on a high-energy pulsed ultrasonic signal, thereby achieving non-contact ultrasonic propagation to acquire the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0072] The waveform receiving module is configured to analyze the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0073] The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0074] The evaluation matrix formulation module is configured to establish hydrogen damage identification criteria based on the correlation between the state characteristic parameters and the hydrogen damage status.

[0075] The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level of the hydrogen pipeline based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

[0076] The hydrogen pipeline damage detection system based on nonlinear ultrasound provided in this invention utilizes the high sensitivity of nonlinear ultrasound detection and comprehensively evaluates the intensity of hydrogen damage by combining time-domain and frequency-domain characteristics. It achieves a non-contact online detection method, which can effectively identify early hydrogen damage characteristics, prevent further damage from causing serious consequences, and ensure the structural integrity of hydrogen pipelines.

[0077] In a preferred embodiment, the signal excitation module is used to generate an excitation signal, including a signal generator 1 and a transmitting transducer 3; in an optional embodiment, in the nonlinear ultrasonic detection device, the signal excitation module is equipped with a signal generator as a signal source, outputting a waveform of a set form to realize the transmission of high-energy pulses; based on this, ultrasonic waves are excited in the pipe under test so that the damage and ultrasonic waves have a nonlinear effect.

[0078] In practical applications, the signal generator outputs waveforms in various forms, such as sine waves and modulation, to achieve the transmission of high-energy pulses. In a preferred embodiment, the signal generator outputs a sine pulse train signal modulated by a Hanning window function. The signal modulated by the window function reduces spectral leakage and provides more concentrated ultrasonic energy.

[0079] Here, the ultrasonic excitation signal is set as a sinusoidal pulse train signal modulated by the Hanning window function. Its advantage is that the signal after window function modulation not only retains the advantages of the sinusoidal continuous pulse signal, but also reduces spectral leakage and obtains more concentrated ultrasonic energy.

[0080] Considering that air-coupled ultrasonic transducers, while possessing the functions of traditional ultrasonic transducers, can propagate ultrasonic waves through air without the need for coupling agent, thus achieving non-contact detection, this invention utilizes the performance of air-coupled ultrasonic transducers to achieve non-contact transmission and conversion of ultrasonic waves.

[0081] The signal excitation module is equipped with a transmitting transducer, which uses the inverse piezoelectric effect to convert electrical signals into vibration signals and transmit them to the test sample, thereby realizing non-contact ultrasonic excitation and performing non-contact detection.

[0082] In practical applications, the transmitting transducer uses the inverse piezoelectric effect to convert electrical signals into vibration signals, i.e., ultrasonic waves, and transmits them to the test sample to achieve ultrasonic excitation.

[0083] Because the ultrasonic signals generated by the system are quite complex, they need to be filtered to eliminate interference from system nonlinearity before being transmitted to the ultrasonic transducer. Therefore, in a preferred embodiment, the signal excitation module further includes a filter 2, which is connected between the signal generator and the ultrasonic transducer and is configured to filter the signal transmitted to the ultrasonic transducer to eliminate interference from system nonlinearity.

[0084] Furthermore, the waveform receiving module obtains the response signal at the hydrogen damage site to facilitate analysis in the time and frequency domains to determine the nonlinear response of the sample under different damage levels; in a preferred embodiment, the waveform receiving module includes a receiving transducer and an oscilloscope.

[0085] The receiving transducer uses the piezoelectric effect to convert the test response vibration signal of the sample into an electrical signal, which is then transmitted to an oscilloscope. The oscilloscope then displays the test response electrical signal as waveform information, which can be further transmitted to a computer 6 for subsequent analysis by the operator.

[0086] In a preferred embodiment, the signal excitation module and the receiving transducer are respectively mounted on the scanning bracket, and one side of the oscilloscope is connected to the receiving transducer, while the other side is connected to the computer system.

[0087] In practical applications, the output of signal generator 1 is connected to the input of low-pass filter 2, and the output of low-pass filter 2 is connected to transmitting transducer 3. Ultrasonic waves are excited in the sample to form a nonlinear response signal. After being received by receiving transducer 4, the signal is connected to oscilloscope 5 for display and connected to the matching software on computer 6 to realize synchronous transmission and calculation analysis of waveform data.

[0088] Based on the above structural configuration, relevant parameters are set before detection, such as the frequency, amplitude, and number of cycles of the transmitted signal, the receiving gain multiple, the oscilloscope sampling frequency, and the storage length. The parameter values ​​will be described in detail in the embodiments.

[0089] To assess the damage status of hydrogen pipelines, it is necessary to establish the relationship between nonlinear ultrasonic signal parameters and the severity of hydrogen damage. However, the uncertainty of a single signal parameter is high, and it does not reflect the damage information comprehensively enough. Therefore, harmonic energy E is extracted through time-domain analysis. m The nonlinear coefficient β is extracted through frequency domain analysis, and the severity of hydrogen damage is assessed by combining both methods. Figure 2 A schematic diagram of the detection process of the hydrogen pipeline damage state detection system based on nonlinear ultrasound provided in an embodiment of the present invention is shown.

[0090] The nonlinear coefficient β is commonly used for the quantitative evaluation of material damage accumulation processes. When ultrasound passes through a microcrack, it excites a nonlinear effect. As damage accumulates or the microstructure changes, the nonlinear effect significantly increases, manifesting as an increase in the amplitude of higher harmonics. This invention uses the β value to quantitatively characterize nonlinear spectral signals.

[0091] Therefore, in this embodiment of the invention, the nonlinear coefficient β and harmonic energy E are calculated based on the detection response waveform information using both time-domain and frequency-domain waveforms. m In a preferred embodiment, the feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0092] The feature parameter calculation module calculates the nonlinear coefficients and harmonic energy based on the time-domain and frequency-domain information of the nonlinear response waveform information.

[0093] The nonlinear coefficients are calculated as follows:

[0094] After denoising and filtering the received ultrasonic signal, a Fast Fourier Transform (FFT) is performed to obtain the spectral information. The nonlinear coefficients are then calculated based on the amplitudes of the fundamental frequency signal and the second harmonic signal corresponding to the spectral information. The denoising and filtering process removes unnecessary interference from the external environment and the instrument itself. A FFT is then performed to obtain the spectral information, and the amplitudes of the fundamental frequency signal A1 and the second harmonic signal A2 are calculated based on this spectral information.

[0095] Harmonic energy is used to assess new frequency components related to early material damage that appear during the testing process. These generally include higher harmonics, difference frequencies, and harmonics, and are measured via harmonic energy E. m The energy of harmonics in a time-domain signal is calculated to characterize the intensity of the nonlinear time-domain response.

[0096] Calculate harmonic energy using the following steps:

[0097] The intensity of the nonlinear time-domain response is characterized by calculating the energy magnitude of harmonics in the time-domain signal as a harmonic energy characteristic parameter.

[0098] The characteristic parameter calculation module calculates the nonlinear coefficient β using the following formula:

[0099]

[0100] In the formula, x is the propagation distance of the wave, k is the wave number, A1 is the amplitude of the fundamental frequency signal, and A2 is the amplitude of the second harmonic signal; since x and k are constant values ​​in the experiment, the above formula can be simplified to:

[0101]

[0102] The nonlinear effect in the sample is mainly caused by the interaction between ultrasound and microstructures such as grain boundary dislocations, zone slip, and micropores. Different degrees of hydrogen damage result in different microdefect configurations. The larger the β value, the more obvious the nonlinearity in the region and the more severe the hydrogen damage.

[0103] Considering that the β value may differ under different samples or different experiments, a normalization method is introduced. Therefore, in a preferred embodiment, the feature parameter calculation module is further configured to normalize the nonlinear coefficient, map β to a set range to obtain a relative nonlinear coefficient, which serves as the final nonlinear feature parameter for evaluating frequency domain features.

[0104] In practical applications, β is mapped to the range of 0 to 1 to obtain the relative nonlinear coefficient β, which is used as the final value for evaluating the frequency domain characteristics.

[0105] Next, the variation value Δβ between the maximum and minimum values ​​of each damage level is used as the threshold criterion for classifying the levels. Based on the analysis of experimental data, for the nonlinear coefficient characteristic parameter, 0.2Δβ and 0.7Δβ are selected as critical points, dividing the level into 3 levels: β≤0.2Δβ, 0.2Δβ<β<0.7Δβ, and β≥0.7Δβ.

[0106] The nonlinearity of the three levels mentioned above gradually increases across the three stages, and is divided into three levels: low, medium, and high. The definitions of each level are as follows: low indicates that the signal is slightly damaged and does not require much attention; medium indicates moderate damage, at which point obvious nonlinear signals appear; and high indicates severe damage, which requires close attention.

[0107] On the other hand, in an optional embodiment, the feature parameter calculation module is further configured to normalize the harmonic energy, map the harmonic energy to a set range to obtain the relative harmonic energy, and use it as the final harmonic energy feature parameter for evaluating the time-domain energy characteristics.

[0108] For the characteristic parameters of harmonic energy, the variation value ΔE between the maximum and minimum values ​​at each damage level is used. m 0.2ΔE was chosen as the discrimination limit for classifying hydrogen damage. m and 0.7△E m As a critical point, it is divided into 3 levels.

[0109] In a preferred embodiment, the feature parameter calculation module is configured to extract the envelope of the time-domain signal using the Hilbert-Huang transform, take the modulus of the signal, determine the upper and lower envelopes corresponding to the second harmonic frequency, and calculate the average of the two as the harmonic energy feature parameter.

[0110] In practical applications, the feature parameter calculation module uses the Hilbert-Huang transform to extract the envelope of the time-domain signal, and takes the modulus value of the signal to find the upper envelope m corresponding to the second harmonic frequency 2f. up and lower envelope m down And calculate the average of the two, E. m :

[0111] E m =(m up +m dpwn ) / 2

[0112] Considering E under different samples or different experiments m The values ​​may differ, so a normalization method is introduced to normalize E. m Mapping to the range of 0 to 1 yields the relative harmonic energy E. m , which serves as the final value for evaluating time-domain characteristics.

[0113] Then, the variation value ΔE between the maximum and minimum values ​​for each degree of damage was used. m As the criterion for classification, 0.2ΔE was selected based on experimental data analysis. m and 0.7△E m As a critical point, it is divided into 3 levels, namely E m ≤0.2△E m 0.2△E m <E m <0.7E m E m ≥0.7△E m ;

[0114] The above three levels correspond to three stages where the signal energy gradually increases. According to the low, medium and high signal energy, they are divided into three levels: A, B and C. The definitions of each level are as follows: A is a small signal energy, usually indicating minor damage that does not require much attention; B is a medium energy level, at which point obvious nonlinear signals appear, indicating significant damage; C is a high energy level, with a large number of nonlinear signals appearing, indicating that the structure is undergoing violent activity, usually indicating severe damage and a high probability of failure.

[0115] In this embodiment of the invention, the evaluation matrix formulation module is configured to establish a hydrogen damage identification criterion based on the correlation between the nonlinear coefficient β of the state characteristic parameter and the relative harmonic energy and the hydrogen damage status.

[0116] Based on the above calculations, the relative nonlinear coefficient β and the relative harmonic energy E m Two indicators are used to establish a comprehensive evaluation matrix. The nonlinear coefficient β, calculated in the frequency domain, forms the ordinate of the matrix. Based on the calculated β, levels are categorized as low, medium, and high. The harmonic energy E, calculated in the time domain... m The x-coordinate of the matrix is ​​determined by the harmonic energy E. m The analysis results are categorized into three levels: A, B, and C. The comprehensive grading assessment matrix has four different levels, each corresponding to a different degree of injury severity. Injury severity increases progressively from level I to level IV, as shown in the grading diagram below. Figure 3 As shown.

[0117] Level I: Low level, inactive, medium to low intensity, both signal activity and intensity are at a low level.

[0118] Level II: Medium level, the ultrasound signal has inactive, high intensity characteristics or weakly active, medium to low intensity characteristics, and is located in the middle level.

[0119] Level III: Higher level, with ultrasonic signals exhibiting characteristics of weak activity, high or moderate activity, low to medium intensity, or strong activity and low intensity. Hydrogen damage is already quite severe and there is a risk of further spread, requiring close monitoring.

[0120] Level IV: High level, with ultrasonic signals exhibiting moderate activity and high intensity, or strong activity and medium-to-high intensity. At this stage, hydrogen damage is already severe and will continue to spread, requiring timely maintenance.

[0121] Based on the hydrogen damage level assessed above, if the level is classified as Level III or above, an automatic alarm will be triggered.

[0122] The assessment matrix formulation module is configured to use the variation value Δβ between the maximum and minimum values ​​of each damage level as the discrimination limit for classifying hydrogen damage, and select 0.2Δβ and 0.7Δβ as critical points to divide it into 3 levels.

[0123] The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

[0124] In actual testing applications, a hydrogen damage detection program is developed using the LabVIEW programming system based on the above hydrogen damage assessment indicators. The hydrogen damage assessment module uses the hydrogen damage detection program to automatically detect and alarm.

[0125] The hydrogen pipeline damage status detection system based on nonlinear ultrasound also includes an interactive interface module, which is equipped with a front panel. The front panel includes functions such as sampling channel settings, spectrum display, level calculation, Boolean indicator alarms, and file storage diagrams. Figure 4 As shown.

[0126] After the program is run, real-time detection of hydrogen damage within the region begins. During the detection process, the received detection response waveform signal is analyzed and evaluated based on the nonlinear coefficient β and harmonic energy E corresponding to the detection response waveform signal. m The relative values ​​are set in the block diagram, and the trigger threshold β is set accordingly. th and E th The Boolean indicator is controlled by a For loop. When the signal amplitude exceeds the trigger threshold, the For loop is set to true, and the Boolean indicator lights up, triggering an impact alarm. When the signal amplitude is below the trigger threshold, the For loop outputs false, the Boolean indicator turns off, the detection system continues to run, and the parameters are stored in a text file for the loop to continue.

[0127] It is important to note that β th and E th Through multiple preliminary experiments, it was determined that setting the value too high may cause missed detections, while setting the value too low may easily trigger false alarms and affect the reliability of the system.

[0128] Preferably, in practical applications, an audible alarm can be added to the Boolean light to attract attention and achieve a better warning effect.

[0129] The hydrogen pipeline damage detection system based on nonlinear ultrasound provided in this invention provides accurate and intuitive detection of hydrogen pipeline damage, avoiding some drawbacks of traditional ultrasonic testing. It does not cause contamination to the pipeline surface and can achieve in-situ online identification, providing technical support for efficient and intuitive detection of hydrogen damage in in-service hydrogen pipelines.

[0130] Example 2:

[0131] The hydrogen pipeline damage status detection system based on nonlinear ultrasound provided in this embodiment of the invention includes: a nonlinear ultrasound detection device, a characteristic parameter calculation module, an evaluation matrix formulation module, and a hydrogen damage assessment module;

[0132] The nonlinear ultrasonic testing device includes a signal excitation module and a waveform receiving module;

[0133] The signal excitation module is configured to achieve ultrasonic excitation and non-contact ultrasonic propagation on the test sample based on high-energy pulsed ultrasonic signals, and to obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0134] The waveform receiving module is configured to analyze the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0135] The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0136] The evaluation matrix formulation module is configured to establish hydrogen damage identification criteria based on the correlation between the state characteristic parameters and the hydrogen damage status.

[0137] The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level of the hydrogen pipeline based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

[0138] In a preferred embodiment, the signal excitation module is used to generate an excitation signal, including a signal generator 1 and a transmitting transducer 3; in an optional embodiment, in the nonlinear ultrasonic detection device, the signal excitation module is equipped with a signal generator as a signal source, outputting a waveform of a set form to realize the transmission of high-energy pulses; based on this, ultrasonic waves are excited in the pipe under test so that the damage and ultrasonic waves have a nonlinear effect.

[0139] In practical applications, the signal generator outputs waveforms in various forms, such as sine waves and modulation, to achieve the transmission of high-energy pulses. In a preferred embodiment, the signal generator outputs a sine pulse train signal modulated by a Hanning window function. The signal modulated by the window function reduces spectral leakage and provides more concentrated ultrasonic energy.

[0140] Here, the ultrasonic excitation signal is set as a sinusoidal pulse train signal modulated by the Hanning window function. The signal modulated by the window function not only retains the advantages of the sinusoidal continuous pulse signal, but also reduces spectral leakage and obtains more concentrated ultrasonic energy.

[0141] The signal excitation module is equipped with a transmitting transducer, which uses the inverse piezoelectric effect to convert electrical signals into vibration signals and transmit them to the test sample, thereby realizing non-contact ultrasonic excitation and performing non-contact detection.

[0142] Air-coupled ultrasonic transducers, while possessing the functions of traditional ultrasonic transducers, enable ultrasonic wave propagation via air, eliminating the need for coupling agents and thus achieving non-contact testing. In practical applications, the transmitting transducer utilizes the inverse piezoelectric effect to convert electrical signals into vibration signals, i.e., ultrasonic waves, which are then transmitted to the test sample to achieve ultrasonic excitation.

[0143] Because the ultrasonic signals generated by the system are quite complex, they need to be filtered to eliminate interference from system nonlinearity before being transmitted to the ultrasonic transducer. Therefore, in a preferred embodiment, the signal excitation module further includes a filter 2, which is connected between the signal generator and the ultrasonic transducer and is configured to filter the signal transmitted to the ultrasonic transducer to eliminate interference from system nonlinearity.

[0144] Furthermore, the waveform receiving module obtains the response signal at the hydrogen damage site to facilitate analysis in the time and frequency domains to determine the nonlinear response of the sample under different damage levels; in a preferred embodiment, the waveform receiving module includes a receiving transducer and an oscilloscope.

[0145] The receiving transducer uses the piezoelectric effect to convert the test response vibration signal of the sample into an electrical signal, which is then transmitted to an oscilloscope. The oscilloscope then displays the test response electrical signal as waveform information, which can be further transmitted to a computer 6 for subsequent analysis by the operator.

[0146] In a preferred embodiment, the signal excitation module and the receiving transducer are respectively mounted on a scanning bracket. One side of the oscilloscope is connected to the receiving transducer, and the other side is connected to the computer system. Embodiment 2 is a variation of Embodiment 1. Therefore, the technical features that are the same as or corresponding to those in Embodiment 1 will not be repeated. The following only describes the distinguishing technical features.

[0147] On the other hand, researchers considered that in actual testing, due to the attenuation of ultrasonic signals, the reliability of identifying long-distance defects may be insufficient, which would lead to insufficient accuracy when applied to damage detection of large-diameter hydrogen pipelines. Therefore, this invention adopts an optimized transducer layout scheme for further improvement.

[0148] In a preferred embodiment, the signal excitation module includes two transmitting transducers, which are symmetrically distributed on both sides of the receiving transducer on the scanning bracket, such as... Figure 5As shown, transmitting transducers are symmetrically arranged on both sides of the pipe, and receiving transducers are arranged in the middle, with a spacing of 10cm between adjacent transducers, forming a "two-transmitter-one-receiver" layout to improve the ultrasonic wave propagation range; as shown. Figure 6 As shown; based on this, automatic scanning is achieved by combining a stepper motor, which greatly improves the detection efficiency. In practical applications, the transmitting and receiving transducers are installed on the scanning bracket, and the position and moving speed of the scanning bracket are controlled by the stepper motor, thereby controlling the transducers to detect different positions of the pipeline; where T1 and T2 are transmitting transducers, and R1 is a receiving transducer. The two transmitting transducers are symmetrically distributed on both sides of the receiving transducer, and the distance between two adjacent transducers is 10cm.

[0149] The optimized transducer layout scheme based on the above embodiments can further improve the reliability of signal measurement results, fundamentally improve the accuracy of system detection data, and is applicable to a variety of measured objects, making it more practical.

[0150] Example 3:

[0151] The hydrogen pipeline damage status detection system based on nonlinear ultrasound provided in this embodiment of the invention includes: a nonlinear ultrasound detection device, a characteristic parameter calculation module, an evaluation matrix formulation module, and a hydrogen damage assessment module;

[0152] The nonlinear ultrasonic testing device includes a signal excitation module and a waveform receiving module;

[0153] The signal excitation module is configured to achieve ultrasonic excitation and non-contact ultrasonic propagation on the test sample based on high-energy pulsed ultrasonic signals, and to obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0154] The waveform receiving module is configured to analyze the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0155] The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0156] The evaluation matrix formulation module is configured to establish hydrogen damage identification criteria based on the correlation between the state characteristic parameters and the hydrogen damage status.

[0157] The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level of the hydrogen pipeline based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

[0158] In a preferred embodiment, the signal excitation module is used to generate an excitation signal, including a signal generator 1 and a transmitting transducer 3; in an optional embodiment, in the nonlinear ultrasonic detection device, the signal excitation module is equipped with a signal generator as a signal source, outputting a waveform of a set form to realize the transmission of high-energy pulses; based on this, ultrasonic waves are excited in the pipe under test so that the damage and ultrasonic waves have a nonlinear effect.

[0159] In practical applications, the signal generator outputs waveforms in various forms, such as sine waves and modulation, to achieve the transmission of high-energy pulses. In a preferred embodiment, the signal generator outputs a sine pulse train signal modulated by a Hanning window function. The signal modulated by the window function reduces spectral leakage and provides more concentrated ultrasonic energy.

[0160] Here, the ultrasonic excitation signal is set as a sinusoidal pulse train signal modulated by the Hanning window function. The signal modulated by the window function not only retains the advantages of the sinusoidal continuous pulse signal, but also reduces spectral leakage and obtains more concentrated ultrasonic energy.

[0161] The signal excitation module is equipped with a transmitting transducer, which uses the inverse piezoelectric effect to convert electrical signals into vibration signals and transmit them to the test sample, thereby realizing non-contact ultrasonic excitation and performing non-contact detection.

[0162] Air-coupled ultrasonic transducers, while possessing the functions of traditional ultrasonic transducers, enable ultrasonic wave propagation via air, eliminating the need for coupling agents and thus achieving non-contact testing. In practical applications, the transmitting transducer utilizes the inverse piezoelectric effect to convert electrical signals into vibration signals, i.e., ultrasonic waves, which are then transmitted to the test sample to achieve ultrasonic excitation.

[0163] Because the ultrasonic signals generated by the system are quite complex, they need to be filtered to eliminate interference from system nonlinearity before being transmitted to the ultrasonic transducer. Therefore, in a preferred embodiment, the signal excitation module further includes a filter 2, which is connected between the signal generator and the ultrasonic transducer and is configured to filter the signal transmitted to the ultrasonic transducer to eliminate interference from system nonlinearity.

[0164] Furthermore, the waveform receiving module obtains the response signal at the hydrogen damage site to facilitate analysis in the time and frequency domains to determine the nonlinear response of the sample under different damage levels; in a preferred embodiment, the waveform receiving module includes a receiving transducer and an oscilloscope.

[0165] The receiving transducer utilizes the piezoelectric effect to convert the detection response vibration signal of the sample into an electrical signal, which is then transmitted to an oscilloscope. The oscilloscope then displays the detection response electrical signal as waveform information, which can be further transmitted to a computer 6 for subsequent analysis by the operator. Example 3 is a variation of Example 1 or 2; therefore, the technical features that are the same as or corresponding to those in Example 1 or 2 will not be repeated. Only the distinguishing technical features will be described below.

[0166] The embodiments of the present invention first set up an experimental system for calibration and verification to verify whether the signal received by the oscilloscope meets the set requirements; after meeting the requirements, the response waveform is received and the nonlinear coefficient and harmonic energy are calculated.

[0167] In a preferred embodiment, the hydrogen pipeline damage state detection system based on nonlinear ultrasound further includes a system calibration unit, which is configured to perform nonlinear coefficient β and harmonic energy E... m Before the calculation, it is necessary to verify whether the signal received by the oscilloscope meets the time requirements and theoretical position requirements of the primary reflected wave signal of the ultrasonic transducer.

[0168] The system calibration unit is also configured to verify whether the distribution of the fundamental frequency signal and the second harmonic signal of the signal received by the oscilloscope meets the set requirements.

[0169] The system calibration unit verifies that the signal received by the oscilloscope is the first reflected wave signal emitted by the ultrasonic transducer. The ultrasonic signal path is used to calculate whether the time of the first echo signal appears matches the theoretical position, and to determine whether the maximum value of the fundamental frequency signal is around 5MHz and whether the maximum value of the second harmonic signal is around 10MHz.

[0170] The embodiments of the present invention calibrate the attribute characteristics of the signal received by the oscilloscope in advance through the system calibration unit, which can ensure the authenticity and accuracy of the ultrasonic signal characteristic data during actual operation, and fundamentally avoid data errors and interference caused by functional module malfunctions.

[0171] The present invention will be further described below with reference to specific embodiments. The scope of the present invention is not limited to the embodiments, but is defined in the claims.

[0172] In the hydrogen pipeline damage detection system based on nonlinear ultrasound provided in this embodiment of the invention, each module or unit structure can operate independently or in combination according to actual structural connection requirements and model processing requirements to achieve the corresponding technical effects.

[0173] Implementation Case 1:

[0174] The hydrogen damage status detection system based on nonlinear ultrasound described in this invention is used for detecting hydrogen damage in overhead hydrogen pipelines.

[0175] First, install the transducers in the corresponding positions on the scanning bracket, with the transmitting transducers symmetrically arranged on both sides of the receiving transducer.

[0176] The detection parameters are set as follows: transmit pulse frequency is 5MHz, voltage amplitude is 10V, Hanning window modulation, signal cycle number is 20, second harmonic receiver input gain is 100dB, oscilloscope sampling frequency is 625kHz, and oscilloscope sampling time is 200ms.

[0177] The scanning device then moves at a constant speed along the pipe, and the computer calculates and analyzes the nonlinear coefficient β and harmonic energy E in real time. m The results are input into the LabVIEW program of the hydrogen damage assessment module. If the hydrogen damage level of a certain area is ≥ Level III during the scanning process, the computer will record the distance of the area from the starting detection point and issue an audible and visual alarm to remind the maintenance personnel.

[0178] Implementation Case 2:

[0179] The hydrogen damage status detection system based on nonlinear ultrasound described in this invention is used to detect hydrogen damage in high-pressure storage tanks at hydrogen refueling stations.

[0180] First, install the transducers in the corresponding positions on the scanning bracket, with the transmitting transducers symmetrically arranged on both sides of the receiving transducer.

[0181] The detection parameters are set as follows: transmit pulse frequency is 5MHz, voltage amplitude is 10V, Hanning window modulation, signal cycle number is 20, second harmonic receiver input gain is 100dB, oscilloscope sampling frequency is 625kHz, and oscilloscope sampling time is 200ms.

[0182] The scanning device then moves at a constant speed on the storage tank, and the computer calculates and analyzes the nonlinear coefficient β and harmonic energy E in real time. m The results are input into the LabVIEW program of the hydrogen damage assessment module. If the hydrogen damage level of a certain area is ≥ Level III during the scanning process, the computer will record the distance of the area from the starting detection point and issue an audible and visual alarm to remind the maintenance personnel.

[0183] Implementation Case 3:

[0184] The hydrogen damage status detection system based on nonlinear ultrasound described in this invention is used to detect hydrogen damage in hydrogen process pipelines at hydrogen refueling stations.

[0185] The seamless steel pipes used in hydrogen refueling stations have relatively small diameters, and a single transducer can basically cover the detection area circumferentially. Therefore, it is considered to arrange the transducers along the axial direction to improve the detection speed. The layout is as follows: Figure 7 As shown; T1 and T2 are transmitting transducers, and R1 is a receiving transducer. The transducers are installed at the corresponding positions on the scanning bracket, with the transmitting transducers symmetrically arranged on both sides of the receiving transducer.

[0186] The detection parameters are set as follows: transmit pulse frequency is 5MHz, voltage amplitude is 10V, Hanning window modulation, signal cycle number is 20, second harmonic receiver input gain is 100dB, oscilloscope sampling frequency is 625kHz, and oscilloscope sampling time is 200ms.

[0187] The scanning device then moves at a constant speed along the hydrogen pipeline, and the computer calculates and analyzes the nonlinear coefficient β and harmonic energy E in real time. m The results are input into the LabVIEW program of the hydrogen damage assessment module. If the hydrogen damage level of a certain area is ≥ Level III during the scanning process, the computer will record the distance of the area from the starting detection point and issue an audible and visual alarm to remind the maintenance personnel.

[0188] Hydrogen damage inside a hydrogen pipeline will affect the overall elastic modulus and reduce the longitudinal and transverse wave velocities of ultrasonic waves propagating within the material. Therefore, in practical applications, the nonlinear ultrasonic-based hydrogen pipeline damage detection system described in this invention can be used to measure the ultrasonic wave velocity inside the hydrogen pipeline, as illustrated in the following implementation example:

[0189] Implementation Case 4:

[0190] Using the system described in this invention, an ultrasonic guided wave is emitted by a transmitting transducer. The time t1 for the wave to first propagate to the receiving transducer is recorded. It then continues to propagate circumferentially through the pipe and is received a second time by the receiving transducer, recorded as t2. The interval Δt between the first time t1 and the second time t2 is the time it takes for the guided wave to propagate a full circle around the pipe. The circumferential ultrasonic wave velocity v is calculated using the following formula:

[0191]

[0192] Where v is the circumferential ultrasonic wave velocity, D is the outer diameter of the pipe, and Δt is the interval time;

[0193] The extent of hydrogen damage in the region can be determined by comparing the circumferential ultrasonic wave velocity v.

[0194] On the other hand, if hydrogen damage occurs inside the hydrogen pipeline, it will lead to an increase in the gaps between grains in the microstructure, thereby increasing the ultrasonic path and macroscopically manifesting as an increase in wall thickness. Therefore, the hydrogen pipeline damage state detection system based on nonlinear ultrasound of the present invention can be used to measure the thickness to determine the possibility of hydrogen damage in the pipeline, as shown in the following implementation examples:

[0195] Implementation Case 5:

[0196] First, ultrasonic waves are emitted through a transducer. After propagating along the depth of the pipe, the ultrasonic waves are received again by the transducer. The time t1 corresponding to the maximum amplitude of the first echo and the time t2 corresponding to the maximum amplitude of the second echo are taken, and the difference between the two is Δt. The wall thickness d at this location can then be calculated using the following formula:

[0197] d=u△t

[0198] Where d is the pipe wall thickness and u is the theoretical speed at which ultrasonic waves propagate in the steel structure, the hydrogen damage in the region can be determined by comparing the wall thickness d.

[0199] The hydrogen pipeline damage detection system based on nonlinear ultrasound provided in this invention can identify early hydrogen damage in in-service hydrogen-related equipment, enabling timely preventative maintenance and preventing irreversible damage. Specifically, the transducer layout is tailored to the shape characteristics of the hydrogen pipeline, improving detection coverage and efficiency. Furthermore, considering the significant uncertainty of a single evaluation parameter, time-domain and frequency-domain feature parameters are extracted and jointly characterized. A comprehensive assessment of the degree of hydrogen damage is performed; if the defect level is too high, an audible and visual alarm is triggered, reducing manual inspection costs. Moreover, the system is simple in structure, easy to install, and reliable in performance.

[0200] Example 4

[0201] The above-described embodiments of the present invention have provided a detailed description of the system. Based on other aspects of the system described in any one or more of the above embodiments, the present invention also provides a method for detecting the damage status of hydrogen pipelines based on nonlinear ultrasound. This method is applied to the nonlinear ultrasound-based hydrogen pipeline damage status detection system described in any one or more of the above embodiments. Specific embodiments are given below for detailed description.

[0202] Specifically, Figure 8 The diagram shows a flowchart of the hydrogen pipeline damage state detection method based on nonlinear ultrasound provided in an embodiment of the present invention. Figure 8 As shown, the method includes:

[0203] The test sample is ultrasonically excited by a signal excitation module based on a high-energy pulsed ultrasonic signal, thereby achieving non-contact ultrasonic propagation to obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0204] The waveform receiving module analyzes the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0205] The characteristic parameter calculation module calculates state characteristic parameters, including nonlinear coefficients and harmonic energy, based on the nonlinear response waveform information.

[0206] Using the evaluation matrix formulation module, hydrogen damage identification criteria are established based on the correlation between the state characteristic parameters and the hydrogen damage status.

[0207] Furthermore, based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test, a comprehensive assessment and early warning of the hydrogen damage level of the hydrogen pipeline is conducted.

[0208] In this embodiment of the invention, the hydrogen pipeline damage state detection method based on nonlinear ultrasound is applied to a hydrogen pipeline damage state detection system comprising:

[0209] Nonlinear ultrasonic testing device, characteristic parameter calculation module, evaluation matrix formulation module, and hydrogen damage assessment module;

[0210] The nonlinear ultrasonic testing device includes a signal excitation module and a waveform receiving module;

[0211] The signal excitation module is configured to excite the test sample with high-energy pulsed ultrasonic signals to achieve non-contact ultrasonic propagation and obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage.

[0212] The waveform receiving module is configured to analyze the nonlinear response waveform information of the sample based on the vibration signal of the detected response.

[0213] The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0214] The evaluation matrix formulation module is connected to the feature parameter calculation module and is configured to establish a hydrogen damage identification criterion based on the correlation between the state feature parameters and the hydrogen damage status.

[0215] The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level of the hydrogen pipeline based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

[0216] Optionally, in one embodiment, in the nonlinear ultrasonic testing device, the signal excitation module is equipped with a signal generator as a signal source, which outputs a waveform of a set form to realize the transmission of high-energy pulses.

[0217] Furthermore, in one embodiment, the signal excitation module is equipped with a transmitting transducer, which uses the inverse piezoelectric effect to convert an electrical signal into a vibration signal and transmit it to the test sample, thereby realizing non-contact ultrasonic excitation and performing non-contact detection.

[0218] Preferably, in one embodiment, the signal excitation module further includes a filter connected between the signal generator and the transmitting transducer, configured to filter the signal transmitted to the transmitting transducer to eliminate interference from system nonlinearity.

[0219] In one embodiment, the waveform receiving module includes a receiving transducer and an oscilloscope;

[0220] The receiving transducer uses the piezoelectric effect to convert the test response vibration signal of the sample into an electrical signal, which is then transmitted to an oscilloscope. The oscilloscope then displays the test response electrical signal as waveform information.

[0221] In one optional embodiment, the signal excitation module and the receiving transducer are respectively installed at corresponding positions on the scanning bracket, and one side of the oscilloscope is connected to the receiving transducer, while the other side is connected to the computer system.

[0222] Furthermore, in one embodiment, the signal excitation module includes two transmitting transducers, which are symmetrically distributed on both sides of the receiving transducer on the scanning bracket.

[0223] In a preferred embodiment, the feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy.

[0224] The feature parameter calculation module calculates the nonlinear coefficients and harmonic energy based on the time-domain and frequency-domain information of the nonlinear response waveform information.

[0225] The nonlinear coefficients are calculated as follows:

[0226] After the received ultrasonic signal is denoised and filtered, a fast Fourier transform is performed to obtain the spectrum information. The nonlinear coefficient is calculated based on the amplitude of the fundamental frequency signal and the amplitude of the second harmonic signal corresponding to the spectrum information.

[0227] Calculate harmonic energy using the following steps:

[0228] The intensity of the nonlinear time-domain response is characterized by calculating the energy magnitude of harmonics in the time-domain signal as a harmonic energy characteristic parameter.

[0229] Preferably, in one embodiment, the feature parameter calculation module calculates the nonlinear coefficient β using the following formula:

[0230]

[0231] In the formula, x is the propagation distance of the wave, k is the wave number, A1 is the amplitude of the fundamental frequency signal, and A2 is the amplitude of the second harmonic signal.

[0232] In an optional embodiment, the feature parameter calculation module is further configured to normalize the nonlinear coefficients, mapping the nonlinear coefficients to a set range to obtain relative nonlinear coefficients, which serve as the final nonlinear feature parameters for evaluating frequency domain features.

[0233] Furthermore, in one embodiment, the feature parameter calculation module is configured to extract the envelope of the time-domain signal using the Hilbert-Huang transform, and to take the modulus value of the signal to determine the upper and lower envelopes at the corresponding second harmonic frequencies, and to calculate the average value of the two as the harmonic energy feature parameter.

[0234] In a preferred embodiment, the feature parameter calculation module is further configured to normalize the harmonic energy, map the harmonic energy to a set range to obtain the relative harmonic energy, which serves as the final harmonic energy feature parameter for evaluating the time-domain energy characteristics.

[0235] Furthermore, in one embodiment, the evaluation matrix formulation module is configured to, for the nonlinear coefficient characteristic parameter, use the change value Δβ between the maximum and minimum values ​​of each damage degree as the discrimination limit for classifying hydrogen damage, selecting 0.2Δβ and 0.7Δβ as critical points, corresponding to three levels; for the harmonic energy characteristic parameter, use the change value ΔE between the maximum and minimum values ​​of each damage degree. m 0.2ΔE was chosen as the discrimination limit for classifying hydrogen damage. m and 0.7△E m As a critical point, it is divided into 3 levels.

[0236] In an optional embodiment, the signal generator outputs a sinusoidal pulse train signal modulated by a Hanning window function. The signal modulated by the window function reduces spectral leakage and provides more concentrated ultrasonic energy.

[0237] On the other hand, in a preferred embodiment, the system further includes a system calibration unit configured to verify whether the signal received by the oscilloscope meets the time requirements and theoretical position requirements of the primary reflected wave signal of the ultrasonic transducer.

[0238] Furthermore, in one embodiment, the system calibration unit is also configured to verify whether the distribution of the fundamental frequency signal and the second harmonic signal of the signal received by the oscilloscope meets the set requirements.

[0239] For the foregoing method embodiments, in order to simplify the description, they are all described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, because according to the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0240] It should be noted that, in other embodiments of the present invention, the method can also be combined with one or more of the above embodiments to obtain a new nonlinear ultrasound-based hydrogen pipeline damage state detection method, so as to achieve dynamic and reliable detection of hydrogen pipeline damage state.

[0241] Example 5:

[0242] It should be noted that, based on the methods in any one or more embodiments of the present invention described above, the present invention also provides a storage medium storing program code that can implement the methods described in any one or more embodiments. When the program code is executed by the operating system, it can implement the hydrogen pipeline damage state detection method based on nonlinear ultrasound as described above.

[0243] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0244] The phrase "an embodiment" in the specification means that a specific feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0245] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A hydrogen pipeline damage condition detection system based on nonlinear ultrasound, characterized in that, The system includes: a nonlinear ultrasonic detection device, a characteristic parameter calculation module, an evaluation matrix formulation module, and a hydrogen damage assessment module; The nonlinear ultrasonic testing device includes a signal excitation module and a waveform receiving module; The signal excitation module is configured to excite the test sample with high-energy pulsed ultrasonic signals to achieve non-contact ultrasonic propagation and obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage. The waveform receiving module is configured to analyze the nonlinear response waveform information of the sample based on the vibration signal of the detected response. The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy. The evaluation matrix formulation module is connected to the feature parameter calculation module and is configured to establish a hydrogen damage identification criterion based on the correlation between the state feature parameters and the hydrogen damage status. The hydrogen damage assessment module is configured to comprehensively assess and issue early warnings for the hydrogen damage level of the hydrogen pipeline based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test.

2. The system according to claim 1, characterized in that, In the nonlinear ultrasonic testing device, the signal excitation module is equipped with a signal generator as a signal source, which outputs a waveform of a set form to realize the transmission of high-energy pulses.

3. The system according to claim 1, characterized in that, The signal excitation module is equipped with a transmitting transducer, which uses the inverse piezoelectric effect to convert electrical signals into vibration signals and transmit them to the test sample, thereby realizing non-contact ultrasonic excitation and performing non-contact detection.

4. The system according to claim 1 or 2, characterized in that, The signal excitation module also includes a filter connected between the signal generator and the transmitting transducer, configured to filter the signal transmitted to the transmitting transducer to eliminate interference from system nonlinearity.

5. The system according to claim 1, characterized in that, The waveform receiving module includes a receiving transducer and an oscilloscope; The receiving transducer uses the piezoelectric effect to convert the test response vibration signal of the sample into an electrical signal, which is then transmitted to an oscilloscope. The oscilloscope then displays the test response electrical signal as waveform information.

6. The system according to claim 5, characterized in that, The signal excitation module and the receiving transducer are respectively installed at corresponding positions on the scanning bracket. One side of the oscilloscope is connected to the receiving transducer, and the other side is connected to the computer system.

7. The system according to claim 6, characterized in that, The signal excitation module includes two transmitting transducers, which are symmetrically distributed on both sides of the receiving transducer on the scanning bracket.

8. The system according to claim 1, characterized in that, The feature parameter calculation module is configured to calculate state feature parameters based on the nonlinear response waveform information, including nonlinear coefficients and harmonic energy. The feature parameter calculation module calculates the nonlinear coefficients and harmonic energy based on the time-domain and frequency-domain information of the nonlinear response waveform information. The nonlinear coefficients are calculated as follows: After the received ultrasonic signal is denoised and filtered, a fast Fourier transform is performed to obtain the spectrum information. The nonlinear coefficient is calculated based on the amplitude of the fundamental frequency signal and the amplitude of the second harmonic signal corresponding to the spectrum information. Calculate harmonic energy using the following steps: The intensity of the nonlinear time-domain response is characterized by calculating the energy magnitude of harmonics in the time-domain signal as a harmonic energy characteristic parameter.

9. The system according to claim 1, characterized in that, The characteristic parameter calculation module calculates the nonlinear coefficient β using the following formula: In the formula, x is the propagation distance of the wave, k is the wave number, A1 is the amplitude of the fundamental frequency signal, and A2 is the amplitude of the second harmonic signal.

10. The system according to claim 1, characterized in that, The feature parameter calculation module is also configured to normalize the nonlinear coefficients, map the nonlinear coefficients to a set range to obtain relative nonlinear coefficients, and use them as the final nonlinear feature parameters for evaluating frequency domain features.

11. The system according to claim 1, characterized in that, The feature parameter calculation module is configured to extract the envelope of the time-domain signal using Hilbert-Huang transform, take the modulus value of the signal, determine the upper and lower envelopes at the corresponding second harmonic frequencies, and calculate the average value of the two as the harmonic energy feature parameter.

12. The system according to claim 1, characterized in that, The feature parameter calculation module is also configured to normalize the harmonic energy, map the harmonic energy to a set range to obtain the relative harmonic energy, and use it as the final harmonic energy feature parameter for evaluating the time-domain energy characteristics.

13. The system according to claim 1, characterized in that, The evaluation matrix formulation module is configured such that, for the nonlinear coefficient characteristic parameter, the variation value Δβ between the maximum and minimum values ​​of each damage level is used as the discrimination limit for classifying hydrogen damage, and 0.2Δβ and 0.7Δβ are selected as critical points, corresponding to three levels; for the harmonic energy characteristic parameter, the variation value ΔE between the maximum and minimum values ​​of each damage level is used. m 0.2ΔE was chosen as the discrimination limit for classifying hydrogen damage. m and 0.7△E m As a critical point, it is divided into 3 levels.

14. The system according to claim 2, characterized in that, The signal generator outputs a sinusoidal pulse train signal modulated by the Hanning window function. The signal modulated by the window function reduces spectral leakage and provides more concentrated ultrasonic energy.

15. The system according to claim 1, characterized in that, The system also includes a system calibration unit configured to verify whether the signal received by the oscilloscope meets the time requirements and theoretical position requirements of the primary reflected wave signal of the ultrasonic transducer.

16. The system according to claim 15, characterized in that, The system calibration unit is also configured to verify whether the distribution of the fundamental frequency signal and the second harmonic signal of the signal received by the oscilloscope meets the set requirements.

17. A method for detecting damage status in hydrogen pipelines based on nonlinear ultrasound, characterized in that, The method is applied to a system performing any one of claims 1 to 16, the method comprising: The test sample is ultrasonically excited by a signal excitation module based on a high-energy pulsed ultrasonic signal, thereby achieving non-contact ultrasonic propagation to obtain the vibration signal of the detection response; the test sample includes hydrogen pipeline samples with different levels of hydrogen damage. The waveform receiving module analyzes the nonlinear response waveform information of the sample based on the vibration signal of the detected response. The characteristic parameter calculation module calculates state characteristic parameters, including nonlinear coefficients and harmonic energy, based on the nonlinear response waveform information. Using the evaluation matrix formulation module, hydrogen damage identification criteria are established based on the correlation between the state characteristic parameters and the hydrogen damage status. Based on the hydrogen damage identification matrix and the state characteristic parameters of the detection response of the hydrogen pipeline under test, a comprehensive assessment and early warning of the hydrogen damage level of the hydrogen pipeline is performed.

18. A storage medium, characterized in that, The storage medium stores program code that can implement the method as described in claim 17.

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