A method and device for detecting defects in the inner liner of a double-layer hydrogen storage bottle

Abstract

The present application discloses a method and device for detecting defects in the inner liner of a double-layer hydrogen storage bottle, relating to the technical field of ultrasonic flaw detection; the method includes: moving an ultrasonic probe from a first stepping window to a second stepping window based on a preset detection path; the ultrasonic probe is an air-coupled ultrasonic detection probe; performing air-coupled ultrasonic detection on a second detection window by using the ultrasonic probe based on a preset detection frequency of the second stepping window to obtain detection data; the second detection window is the inner liner area detected by the ultrasonic probe at the current moment, and the second detection window corresponds to the position of the second stepping window; determining the status information of the second detection window based on the detection data; the status information indicates whether there are defects in the second detection window. The technical solution provided by the present application can realize the detection of defects in a double-layer hydrogen storage bottle by using ultrasonic waves.

Description

Technical Field

[0001] This application relates to the technical field of ultrasonic flaw detection, and specifically provides a method and device for detecting defects in the inner liner of a double-layer hydrogen storage bottle. Background Art

[0002] Liquid hydrogen is currently the most efficient and convenient hydrogen storage method among solid hydrogen storage, liquid hydrogen storage, and gaseous hydrogen storage. Moreover, the liquid hydrogen supply system has good integration, and the volume-weight ratio can be as high as over 12%. It has great potential in the hydrogen supply system of fuel cell heavy trucks. Liquid hydrogen storage tanks usually need to withstand high-pressure environments and may encounter various mechanical stresses and chemical corrosions during use. Therefore, it is necessary to regularly perform non-destructive testing (NDT) on the hydrogen storage tank to ensure its safety.

[0003] In the prior art, ultrasonic testing is one of the important technical means in NDT applications. Its principle is to use a liquid or gel as a coupling agent, place an ultrasonic probe (which can also be called a transducer) on the surface to be inspected, and emit ultrasonic pulses. The characteristics of the propagation of high-frequency sound waves in the material and the characteristics of the echo signals are used to detect defects. However, with the application of hydrogen storage structures with a double-layer structure of inner and outer liners, the contact ultrasonic testing technology cannot effectively detect the inner liner.

[0004] Therefore, how to overcome the above-mentioned technical problems and defects has become a key issue to be solved. Summary of the Invention

[0005] The purpose of this application is to provide a method and device for detecting defects in the inner liner of a double-layer hydrogen storage bottle to solve the problems raised in the above background art and be able to detect defects in the double-layer hydrogen storage bottle using ultrasonic waves.

[0006] The technical solution of the embodiment of this application is implemented as follows:

[0007] The embodiment of this application provides a method for detecting defects in the inner liner of a double-layer hydrogen storage bottle, and the method includes:

[0008] Based on a preset detection path, move the ultrasonic probe from the first stepping window to the second stepping window; the ultrasonic probe is an air-coupled ultrasonic detection probe;

[0009] Based on the preset detection frequency of the second stepping window, use the ultrasonic probe to perform air-coupled ultrasonic detection on the second detection window to obtain detection data; the second detection window is the inner liner area currently detected by the ultrasonic probe, and the second detection window corresponds to the position of the second stepping window;

[0010] Based on the detection data, determine the status information of the second detection window; the status information indicates whether there are defects in the second detection window.

[0011] In the above solution, before moving the ultrasonic probe from the first stepping window to the second stepping window based on the preset detection path, the method further includes:

[0012] Based on the preset step size of the ultrasonic probe, construct a grid surface on the outer tank surface; the grid surface includes a plurality of first grids.

[0013] Based on the area to be detected of the inner tank, determine the first grids corresponding to the area to be detected from the plurality of first grids to obtain a plurality of second grids.

[0014] Configure the detection path based on the positions of the plurality of second grids.

[0015] In the above solution, the detection data includes the outer tank echo data and the inner tank echo data obtained by air-coupled ultrasonic detection in all detection cycles; the detection cycle is the time between two ultrasonic pulse emissions; the step of using the ultrasonic probe to perform air-coupled ultrasonic detection on the second detection window based on the preset detection frequency of the second stepping window to obtain detection data includes:

[0016] In each detection cycle, after emitting an ultrasonic pulse, sequentially receive the outer tank echo data and the inner tank echo data returned based on the ultrasonic pulse; the outer tank echo data includes the data of the first true echo signal reflected by the outer tank, and the inner tank echo data includes the data of the second true echo signal reflected by the inner tank.

[0017] The step of determining the status information of the second detection window based on the detection data includes:

[0018] Based on all the inner tank echo data in the detection data, determine the status information of the second detection window.

[0019] In the above solution, the step of determining the status information of the second detection window based on all the inner tank echo data in the detection data includes:

[0020] Based on all the inner tank echo data, determine the amplitude of the second true echo signal.

[0021] Based on the difference degree between the amplitude of the second true echo signal and the amplitude of the ultrasonic pulse emitted in the current detection cycle, determine the actual reflection coefficient of the second detection window.

[0022] Based on the acoustic impedance difference between the inner tank and the air, determine the ideal reflection coefficient of the second detection window.

[0023] Based on the difference degree between the actual reflection coefficient and the ideal reflection coefficient, determine whether the actual reflection coefficient is abnormal to obtain a first judgment result;

[0024] When the first judgment result indicates that the actual reflection coefficient is abnormal, the status information indicates that there is a defect in the second detection window.

[0025] In the above solution, the determining the ideal reflection coefficient of the second detection window based on the acoustic impedance difference between the inner container and the air includes:

[0026] Determine the acoustic impedance difference value between the inner container and the air, and determine the acoustic impedance sum value between the inner container and the air;

[0027] Based on the ratio of the acoustic impedance difference value to the acoustic impedance sum value, determine the ideal reflection coefficient.

[0028] In the above solution, the method further includes:

[0029] Based on the time information and intensity information of all echo signals in the inner container echo data, perform time-domain analysis on the inner container echo data to obtain first fluctuation information; the first fluctuation information characterizes the amplitude fluctuation of all echo signals;

[0030] Based on the first fluctuation information, determine whether there is a second additional echo signal in the inner container echo data whose amplitude is lower than the second true echo signal to obtain a second judgment result;

[0031] When the second judgment result indicates that there is a second additional echo signal in the inner container echo data, the status information indicates that there is a defect in the second detection window.

[0032] In the above solution, the method further includes determining the attribute information of the defect existing in the second detection window; the attribute information includes the position of the defect; the determining the attribute of the defect existing in the second detection window includes:

[0033] Based on the echo time of each second additional echo signal in the detection data, determine the distance between the defect in the second detection window and the probe to obtain the defect position.

[0034] In the above solution, the attribute information further includes the defect type; the method further includes:

[0035] Based on the first fluctuation information, determine the distribution characteristics of all second additional echo signals in the detection data to obtain the characteristic information of the second detection window defect;

[0036] Based on the characteristic information, determine the defect type of the second detection window.

[0037] In the above solution, the method further includes:

[0038] Based on the structural parameters of the inner liner, determine the region with stress concentration on the surface of the inner liner to obtain the key region;

[0039] Configure the detection frequencies of the key region and other regions; the number of detections in the key region is greater than that in other regions.

[0040] An embodiment of the present application further provides a defect detection device for the inner liner of a double-layer hydrogen storage bottle. The double-layer hydrogen storage bottle includes an inner liner and an outer liner, and a vacuum pumping port is provided on the front side of the outer liner; the device includes:

[0041] A control unit, configured to move the ultrasonic probe from the first stepping window to the second stepping window based on a preset detection path; the ultrasonic probe is an air-coupled ultrasonic detection probe;

[0042] A detection unit, configured to perform air-coupled ultrasonic detection on the second detection window by using the ultrasonic probe based on the preset detection frequency of the second stepping window to obtain detection data; the second detection window is the inner liner region currently detected by the ultrasonic probe, and the second detection window corresponds to the position of the second stepping window;

[0043] A processing unit, configured to determine the status information of the second detection window based on the detection data; the status information indicates whether there is a defect in the second detection window.

[0044] The double-layer hydrogen storage bottle inner liner defect detection method and device provided by the embodiment of the present application utilize air-coupled ultrasonic waves to emit pulses and receive echo signals from the inner liner, so as to be able to judge the surface state of the current detection region of the inner liner according to the characteristics of the echo signals, realizing non-destructive flaw detection of the inner liner of the hydrogen storage device; further, since the outer liner and the inner liner regions are associated, it is possible to accurately control the probe to perform ultrasonic detection on the target region of the inner liner on the surface of the outer liner, realizing the accuracy and reliability of the detection position. Description of the Drawings

[0045] Figure 1 It is a schematic structural diagram of a double-layer hydrogen storage bottle provided by an embodiment of the present application;

[0046] Figure 2 It is a schematic flowchart of a method for detecting defects in the inner liner of a double-layer hydrogen storage bottle provided by an embodiment of the present application;

[0047] Figure 3 It is a waveform diagram of a dot defect in the method for detecting defects in the inner liner of a double-layer hydrogen storage bottle provided by an embodiment of the present application;

[0048] Figure 4Schematic diagram of echoes when there is no defect in the second detection window in the double-layer hydrogen storage bottle inner liner defect detection method of this application embodiment;

[0049] Figure 5 Schematic diagram of echoes when there is a first-level defect in the second detection window in the double-layer hydrogen storage bottle inner liner defect detection method of this application embodiment;

[0050] Figure 6 Schematic diagram of echoes when there is a second-level defect in the second detection window in the double-layer hydrogen storage bottle inner liner defect detection method of this application embodiment;

[0051] Figure 7 Schematic diagram of echoes when there is a third-level defect in the second detection window in the double-layer hydrogen storage bottle inner liner defect detection method of this application embodiment;

[0052] Figure 8 Schematic diagram of the structure of a double-layer hydrogen storage bottle inner liner defect detection device provided by this application embodiment.

[0053] Main component symbol description:

[0054] 11 - Outer liner; 12 - Inner liner; 13 - Connecting shaft; 14 - Bushing. Detailed implementation manners

[0055] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0056] This application embodiment provides a double-layer hydrogen storage bottle, and this device includes a liquid hydrogen bottle and a pipeline assembly;

[0057] Such as Figure 1As shown, the liquid hydrogen bottle includes an outer container 11 and an inner container 12. A vacuum pumping port is provided on the front side of the outer container 11. During the application of the liquid hydrogen bottle, the space between the outer container 11 and the inner container 12 is evacuated through the vacuum pumping port to form a vacuum cavity therebetween. In the detection state, the vacuum pumping port can be opened to allow the space between the outer container 11 and the inner container 12 to communicate with the external air, forming an air cavity. The front end of the inner container 12 is fixedly connected to the outer container 11, and the rear end of the inner container 12 is movably connected to the outer container 11. Specifically, connecting shafts 13 are respectively provided at the front and rear ends of the inner container 12, and bushings 14 are respectively provided at the front and rear ends of the outer container 11. The connecting shaft 13 at the front end of the inner container 12 is hermetically welded and fixed to the bushing 14 at the front end of the outer container 11, and the connecting shaft 13 at the rear end of the inner container 12 is inserted and matched with the bushing 14 at the rear end of the outer container 11. A vacuum pumping port for the liquid hydrogen bottle is provided on the front side of the outer container 11, and the space between the outer container 11 and the inner container 12 is evacuated by an external vacuum pumping device. In this embodiment, a support structure that can reduce the heat leakage of the system by extending the heat transfer path can be adopted between the connecting shaft 13 and the inner container 12 and between the connecting shaft 13 and the bushing 14. For details, reference can be made to the utility model patent with the authorization number of CN218671590 and the invention creation name of a cryogenic vacuum adiabatic pressure vessel with a double-loop support structure applied by our company recently.

[0058] The double-layer hydrogen storage bottle provided by the embodiment of the present application, through the adoption of the internal and external double-layer structure design, on the one hand, meets the strength requirements of the on-vehicle liquid hydrogen bottle, and on the other hand, can reduce the heat leaking into the liquid hydrogen bottle from the outside through the pipeline, such as heat conduction, heat convection and heat radiation, etc.

[0059] Based on the above double-layer hydrogen storage bottle structure, the embodiment of the present application provides a method for detecting defects in the inner container of a double-layer hydrogen storage bottle, which is applied to an electronic device, and can specifically be applied to electronic devices such as an industrial computer, a personal computer, a cloud server, and a mobile terminal. As Figure 2 shown, the method may include:

[0060] S201: Based on a preset detection path, move the ultrasonic probe from the first stepping window to the second stepping window; the ultrasonic probe is an air-coupled ultrasonic detection probe.

[0061] S202: Based on the preset detection frequency of the second stepping window, use the ultrasonic probe to perform air-coupled ultrasonic detection on the second detection window to obtain detection data; the second detection window is the inner container area currently detected by the ultrasonic probe, and the second detection window corresponds to the position of the second stepping window.

[0062] S203: Based on the detection data, determine the status information of the second detection window; the status information indicates whether there are defects in the second detection window.

[0063] Here, it should be noted that the embodiments of the present application describe the detection process of a double-layer hydrogen storage bottle. Therefore, before implementing the present application, it is necessary to first open the vacuum port provided on the double-layer hydrogen storage bottle to form an air cavity that communicates with the outside air between the inner liner and the outer liner.

[0064] In practical applications, the surface of the outer liner can be meshed according to the moving step size of the probe, and then the detection path can be configured in advance.

[0065] In one embodiment, before moving the ultrasonic probe from the first stepping window to the second stepping window based on the preset detection path, the method may further include:

[0066] Based on the preset step size of the ultrasonic probe, construct a grid surface on the surface of the outer liner; the grid surface includes a plurality of first grids;

[0067] Based on the area to be detected of the inner liner, determine the first grids corresponding to the area to be detected from the plurality of first grids to obtain a plurality of second grids;

[0068] Configure the detection path based on the positions of the plurality of second grids.

[0069] In practical applications, the step size can be determined according to the emission range of the ultrasonic probe on the outer liner. For example, the step size can be set to 1 mm. Taking the step size as the unit, the surface of the outer liner is set as a regular scanning grid. For each grid point, ultrasonic waves are emitted and the reflected waves are received.

[0070] In practical applications, according to the structural parameters of the inner liner and the outer liner, establish the corresponding relationship between the coordinate points of the inner liner and the outer liner, so as to determine the position of the inner liner corresponding to each grid point, and realize the accurate emission of ultrasonic waves to the target detection position of the inner liner, improving the detection accuracy and reliability.

[0071] In practical applications, all areas on the surface of the inner liner can be detected, or only some areas can be detected. For example, there are risk areas with a high probability of defects and safe areas with a low probability of defects on the surface of the inner liner. The risk areas can be used as the areas to be detected for detection and monitoring.

[0072] In one embodiment, the area to be detected of the inner liner can be configured in advance; the configured area to be detected includes:

[0073] The stress concentration areas, including the weld positions and geometric discontinuity positions (such as flange connections);

[0074] The corrosion-sensitive areas, including the bottom, top, and pipe interfaces of the inner liner (such as the connection between the external connecting pipe and the inner liner).

[0075] In practical applications, after determining the area to be detected on the inner tank, according to the correlation relationship between the coordinates of the inner tank and the outer tank, determine the position coordinates on the outer tank corresponding to the area to be detected as the target stepping area; then, select the grid corresponding to the target stepping area from the first grid as the second grid, and then configure the specific detection path according to the position of each second grid. How to configure the path according to multiple path positions is a mature existing technology and will not be elaborated here.

[0076] After configuring the detection path, the corresponding second grid can be sequentially moved and detected according to the detection path, that is, execute S201.

[0077] In practical applications, the time required to detect one second grid can be called a detection cycle. That is to say, the time period from the start of emitting ultrasonic pulses in one second grid to the completion of all detections of that second grid and the movement to the next second grid can be regarded as a detection cycle.

[0078] In practical applications, the first stepping window corresponds to the second grid where the ultrasonic probe is currently located, and the position of the second stepping window corresponds to the second grid where the ultrasonic probe will be located in the next detection cycle; in the initial state, the ultrasonic probe can be first moved to the first second grid corresponding to the detection path, and this grid can also be called the initial grid. After the detection of this grid is completed, move the ultrasonic probe from the initial grid to the next second grid, that is, move the ultrasonic probe from the first stepping window to the second stepping window.

[0079] In practical applications, air-coupled ultrasonic is a detection device for propagating ultrasonic waves in the air.

[0080] In one embodiment, the air-coupled ultrasonic probe can adopt a piezoelectric ceramic probe, a capacitive probe, a laser ultrasonic probe, an electromagnetic acoustic transducer (EMAT), etc.

[0081] In practical applications, after moving to the position to be detected in the current detection cycle, ultrasonic pulses can be emitted for detection; here, for the same area, as the number of detections increases, the accuracy of the detection results increases, but the detection efficiency also decreases; therefore, in order to balance the detection accuracy and detection efficiency, different detection times can be configured according to the importance of the detection position.

[0082] Based on this, in one embodiment, the method may further include:

[0083] Based on the structural parameters of the inner tank, determine the area where the surface stress of the inner tank is concentrated to obtain the key area;

[0084] Configure the detection frequencies for the key area and other areas; the number of detections in the key area is greater than that in other areas.

[0085] Here, in the process of determining the key area, according to the structural parameters, finite element analysis software such as ANSYS, ABAQUS, and COMSOL can be used to establish a three-dimensional model of the inner tank, and then perform finite element analysis on the three-dimensional model to calculate the stress distribution of the inner tank under different working conditions.

[0086] In practical applications, the finite element analysis process can include static analysis and dynamic analysis.

[0087] Here, static analysis includes linear and non-linear static analysis; linear static analysis refers to calculating the stress distribution under a constant load (such as internal pressure), and non-linear static analysis refers to performing non-linear static analysis for the non-linear behavior of materials (such as plastic deformation).

[0088] Dynamic analysis can include fatigue analysis and thermal stress analysis; among them, fatigue analysis can be understood as performing fatigue analysis on the cyclic load experienced by the inner tank during use to predict the generation and development of fatigue cracks, and thermal stress analysis can be understood as performing thermal stress analysis based on the temperature change of the inner tank to calculate the stress caused by the temperature gradient.

[0089] After finite element analysis, by analyzing the finite element results, the areas with stress concentration, that is, the key areas, can be identified.

[0090] In practical applications, during the execution of S202, the detection data obtained can include the echo data of each detection cycle, and the echo data of each detection cycle includes the echo data of the outer tank and the inner tank.

[0091] Based on this, in one embodiment, the detection data includes the echo data of the outer tank and the inner tank obtained by air-coupled ultrasonic detection in all detection cycles; the detection cycle is the time between two ultrasonic pulse emissions.

[0092] Performing air-coupled ultrasonic detection on the second detection window using the ultrasonic probe based on the preset detection frequency of the second step window to obtain detection data may include:

[0093] In each detection cycle, after emitting an ultrasonic pulse, sequentially receive the echo data of the outer tank and the inner tank returned based on the ultrasonic pulse; the echo data of the outer tank includes the data of the first true echo signal reflected by the outer tank, and the echo data of the inner tank includes the data of the second true echo signal reflected by the inner tank;

[0094] Determining the status information of the second detection window based on the detection data includes:

[0095] Based on all the echo data of the inner tank in the detection data, determine the status information of the second detection window.

[0096] In practical applications, after the ultrasonic pulse of the current detection cycle is emitted, according to the properties of the outer tank and the inner tank, the ideal echo times of the outer tank echo signal and the inner tank echo signal can be calculated; here, the echo time can also be called the reflection time.

[0097] In practical applications, the ideal echo time can be determined by the thickness and sound velocity of the transmission medium.

[0098] Exemplarily, the ideal echo time of the outer tank can be determined using the following formula:

[0099]

[0100] where t1 represents the ideal echo time of the outer tank, d1 represents the thickness of the outer tank, c1 represents the sound velocity in the outer tank, and t D represents the delay time;

[0101] The ideal echo time of the inner tank can be determined using the following formula:

[0102]

[0103] where t2 represents the ideal echo time of the inner tank, d air represents the thickness of the air layer between the inner tank and the outer tank, d2 represents the thickness of the inner tank, and c air represents the sound velocity in the air, and c2 represents the sound velocity in the inner tank.

[0104] Based on this, within the current detection cycle, after receiving the echo signal, according to the waveform scan diagram of the echo signal, observe the amplitude and reception time of the received different echo signals, and determine that the waveform received at the ideal echo time is the real echo signal. Specifically, receive the real echo of the outer tank at the ideal echo time of the outer tank, that is, the first real echo signal, and receive the real echo of the inner tank at the ideal echo time of the inner tank, that is, the second real echo signal; here, the real echo can also be called the main echo, the first real echo can also be called the first main echo, and the second real echo can also be called the second main echo.

[0105] In practical applications, after all detections of the current detection window are performed according to the preset detection frequency, all detection data of the current window, that is, the detection data, can be obtained. Then, for the data of each detection cycle in the detection data, according to the ideal echo times of the inner tank and the outer tank, the data of the inner tank and the outer tank can be classified, and thus the echo data of the inner tank and the outer tank can be analyzed, that is, execute S203.

[0106] In practical applications, when there are problems such as unevenness on the detection surface and changes in material properties, there will be a large difference between the actual value of the emission coefficient of the detection surface and the ideal value calculated based on material characteristics and geometric structure. Therefore, during the execution of S203, based on the difference between the actual reflection coefficient and the ideal reflection coefficient, it can be determined whether the echo signal is abnormal, thereby determining whether there are defects in the current detection window.

[0107] Based on this, in one embodiment, the determining the status information of the second detection window based on all the inner tank echo data in the detection data may include:

[0108] Based on all the inner tank echo data, determine the amplitude of the second true echo signal;

[0109] Based on the difference degree between the amplitude of the second true echo signal and the amplitude of the ultrasonic pulse emitted in the current detection period, determine the actual reflection coefficient of the second detection window;

[0110] Based on the acoustic impedance difference between the inner tank and the air, determine the ideal reflection coefficient of the second detection window;

[0111] Based on the difference degree between the actual reflection coefficient and the ideal reflection coefficient, determine whether the actual reflection coefficient is abnormal, and obtain a first judgment result;

[0112] When the first judgment result indicates that the actual reflection coefficient is abnormal, the status information indicates that there are defects in the second detection window.

[0113] In practical applications, when determining the amplitude of the second true echo signal based on all the inner tank echo data, the echo data of each detection period in all the inner tank echo data can be classified, and then the echo signal corresponding to the ideal echo time of each detection period is selected as the true echo signal, that is, the second true echo signal, so that the amplitude of the second true echo signal can be determined.

[0114] In practical applications, when determining the actual reflection coefficient of the second detection window based on the difference degree between the amplitude of the second true echo signal and the amplitude of the ultrasonic pulse emitted in the current detection period, the actual reflection coefficient of the inner tank in each detection period can be calculated first, and then the average value of the actual reflection coefficients of each period of the current detection window (i.e., the second detection window) is used as the actual reflection coefficient of the second detection window.

[0115] Wherein, in each detection period, the corresponding actual reflection coefficient can be calculated according to the ratio of the amplitude of the obtained second true echo signal to the amplitude of the ultrasonic pulse emitted in the corresponding detection period.

[0116] Exemplarily, the actual reflection coefficient of each detection period can be determined using the following formula:

[0117]

[0118] where R0 represents the immediate reflection coefficient, d F represents the echo amplitude, d E represents the reflected wave amplitude.

[0119] In practical applications, the ideal reflection coefficient refers to the reflection coefficient calculated based on known material properties under the ideal condition without defects.

[0120] In one embodiment, determining the ideal reflection coefficient of the second detection window based on the acoustic impedance difference between the inner container and the air may include:

[0121] Determining the difference in acoustic impedance between the inner container and the air, and determining the sum value of the acoustic impedance of the inner container and the air;

[0122] Based on the ratio of the acoustic impedance difference to the sum value of the acoustic impedance, determining the ideal reflection coefficient.

[0123] Exemplarily, the ideal reflection coefficient can be determined using the following formula:

[0124]

[0125] where R I represents the ideal reflection coefficient, Z2 represents the acoustic impedance of the inner container, Z air represents the acoustic impedance of the air layer; the calculation formula for acoustic impedance is: Z = ρc; where ρ represents the medium density and c represents the sound speed in the medium.

[0126] In practical applications, after determining the actual reflection coefficient and the ideal reflection coefficient, it is determined whether the difference between the two exceeds a preset index threshold. If it exceeds, it indicates that there is a defect at this position; here, the preset index threshold can be set according to historical data and specific application scenarios, and the embodiments of the present application do not limit this. Exemplarily, it is determined whether |R I -R0| is greater than 0.15. If |R I -R0| > 0.15, the actual reflection coefficient is abnormal, and the first judgment result indicates that there is a defect in the current detection window. Otherwise, the actual reflection result is normal, and the first judgment result indicates that there is no defect in the current detection window.

[0127] In practical applications, when there are minor defects inside (such as tiny cracks or holes), it may not significantly change the surface reflection coefficient, but it will generate additional echoes. At this time, defects on the inner tank surface may be detected through the reflection coefficient. Therefore, to improve the reliability and accuracy of the detection results, time-domain analysis can also be used to determine whether there are abnormal echoes near the main echo, so as to determine whether there are defects at the current detection position.

[0128] Based on this, in one embodiment, the method may further include:

[0129] Perform time-domain analysis on the inner tank echo data based on the time information and intensity information of all echo signals in the inner tank echo data to obtain first fluctuation information; the first fluctuation information characterizes the amplitude fluctuation of all echo signals;

[0130] Based on the first fluctuation information, determine whether there is a second additional echo signal in the inner tank echo data whose amplitude is lower than that of the second true echo signal, and obtain a second judgment result;

[0131] When the second judgment result indicates that there is a second additional echo signal in the inner tank echo data, the status information indicates that there is a defect in the second detection window.

[0132] In practical applications, when performing time-domain analysis on the inner tank echo data based on the time information and intensity information of all echo signals in the inner tank echo data to obtain first fluctuation information, the amplitude distribution of the inner tank echo signals in each detection period can be determined, thereby obtaining the first fluctuation information; specifically, a time axis can be established according to the time when the second detection window transmits and receives ultrasonic signals.

[0133] In practical applications, when determining whether there is a second additional echo signal in the inner tank echo data whose amplitude is lower than that of the second true echo signal based on the first fluctuation information to obtain a second judgment result, it can be determined whether there are additional echoes around each ideal echo on the time axis. If there are, it means there is a defect in the current detection window; otherwise, there is no defect.

[0134] In actual application, when it is determined that there are defects, the attributes of the echo signals can also be determined according to the parameters of the echo signals.

[0135] Based on this, in one embodiment, the method may further include: determining the attribute information of the defects existing in the second detection window; the attribute information includes the position of the defect.

[0136] In one embodiment, the determination of the attributes of the defects existing in the second detection window may include:

[0137] Based on the echo time of each second additional echo signal in the detection data, determine the distance between the defect and the probe in the second detection window to obtain the defect position.

[0138] In practical applications, the defect position can be understood as the depth of the defect in the inner liner. Specifically, according to the echo time of the second additional echo, the distance between the second additional echo position and the probe can be calculated, so that the depth of the surface defect of the inner liner can be determined based on the distance between the second additional echo position and the probe, the actual distance between the inner liner and the probe, and the thickness of the inner liner.

[0139] In practical applications, the waveforms of different defects may exhibit different characteristics. For example, the waveform of a point defect may be relatively sharp, as Figure 3 shown, the waveforms of defects such as cracks and delaminations may be relatively long, and the wave peaks are approximately broad platforms. Therefore, the type of defect can be judged by the waveform of the second additional echo.

[0140] Based on this, in an embodiment, the attribute information may further include the defect type; the method may further include:

[0141] Based on the first fluctuation information, determine the distribution characteristics of all second additional echo signals in the detection data to obtain the characteristic information of the defects in the second detection window;

[0142] Based on the characteristic information, determine the defect type of the second detection window.

[0143] In practical applications, when determining the defect type of the second detection window based on the characteristic information, the type that matches the characteristic information from the preset defect types can be used as the defect type of the second detection window.

[0144] In practical applications, when the defect area is large, there may be no true echo signal in the received echo signals. Therefore, the size type of the defect can be judged according to the echo situation of the ideal echo time.

[0145] Based on this, in an embodiment, the attribute information may further include the defect grade; the method may further include:

[0146] Based on the first fluctuation information, determine the amplitude information of the second true echo and the second additional echo;

[0147] Based on the amplitude information, determine the defect grade of the second detection window.

[0148] In actual application, the defect level can be understood as the level of the defect size; when determining the defect level of the second detection window based on the amplitude information, it is possible to judge whether there are a second true echo and a second additional echo in the echo according to the amplitude information, and when both exist, compare their sizes, and then determine the defect level of the second detection window according to the comparison result.

[0149] In one embodiment, the defect levels are divided into level one, level two, and level three according to the defect size, and the defect areas of level one to level three decrease in sequence; determining the defect level of the second detection window based on the amplitude information may include:

[0150] When only the second additional echo exists in the echo, the defect level of the current detection is level one;

[0151] When both the second true echo and the second additional echo exist in the echo, and the second true echo is smaller than the second additional echo, the defect level of the current detection is level two;

[0152] When both the second true echo and the second additional echo exist in the echo, and the second true echo is larger than the second additional echo, the defect level of the current detection is level three;

[0153] Exemplarily, Figure 4 show the echo when there is no defect in the second detection window, Figure 5 show the echo when there is a level-one defect, Figure 6 show the echo when there is a level-two defect, Figure 7 show the echo when there is a level-three defect, where T represents the transmitted wave, F represents the additional echo, and B represents the true echo.

[0154] Here, it should be noted that the above embodiments introduce the defect detection process of the inner liner. The detection data of each detection window also includes the echo data of the outer liner. The outer liner can be detected for defects according to the echo data of the outer liner, and the specific detection process can refer to the inner liner defect detection process.

[0155] In summary, the double-layer hydrogen storage bottle inner liner defect detection method provided by the embodiments of the present application uses air-coupled ultrasonic waves to emit pulses and receives the echo signals from the inner liner, so that the surface state of the current detection area of the inner liner can be judged according to the characteristics of the echo signals, realizing non-destructive flaw detection of the inner liner of the hydrogen storage device; further, since the outer liner and the inner liner areas are associated, the probe can be accurately controlled to perform ultrasonic detection on the target area of the inner liner on the surface of the outer liner, realizing the accuracy and reliability of the detection position.

[0156] To implement the double-layer hydrogen storage bottle inner liner defect detection method of the present application, the embodiments of the present application also provide a double-layer hydrogen storage bottle inner liner defect detection device, which is arranged on an electronic device, such as Figure 8As shown, the device may include:

[0157] A control unit 801, configured to move an ultrasonic probe from a first stepping window to the second stepping window based on a preset detection path; the ultrasonic probe is an air-coupled ultrasonic detection probe;

[0158] A detection unit 802, configured to perform air-coupled ultrasonic detection on a second detection window by using the ultrasonic probe based on a preset detection frequency of the second stepping window, so as to obtain detection data; the second detection window is the inner tank area detected by the ultrasonic probe at the current moment, and the second detection window corresponds to the position of the second stepping window;

[0159] A processing unit 803, configured to determine status information of the second detection window based on the detection data; the status information indicates whether there is a defect in the second detection window.

[0160] In one embodiment, the control unit 801 may specifically be configured to:

[0161] Construct a grid surface of the outer tank surface based on a preset step size of the ultrasonic probe; the grid surface includes a plurality of first grids;

[0162] Determine first grids corresponding to the area to be detected of the inner tank from the plurality of first grids, so as to obtain a plurality of second grids;

[0163] Configure a detection path based on the positions of the plurality of second grids.

[0164] In one embodiment, the detection data includes outer tank echo data and inner tank echo data obtained by air-coupled ultrasonic detection in all detection periods; the detection period is the time between two ultrasonic pulse transmissions; the detection unit 802 may specifically be configured to:

[0165] In each detection period, after transmitting an ultrasonic pulse, sequentially receive outer tank echo data and inner tank echo data returned based on the ultrasonic pulse; the outer tank echo data includes data of a first true echo signal reflected by the outer tank, and the inner tank echo data includes data of a second true echo signal reflected by the inner tank;

[0166] The processing unit 803 may specifically be configured to:

[0167] Determine the status information of the second detection window based on all the inner tank echo data in the detection data.

[0168] In one embodiment, the processing unit 803 may specifically be configured to:

[0169] Determine the amplitude of the second true echo signal based on all the echo data of the inner container;

[0170] Determine the actual reflection coefficient of the second detection window based on the difference between the amplitude of the second true echo signal and the amplitude of the ultrasonic pulse emitted in the current detection period;

[0171] Determine the ideal reflection coefficient of the second detection window based on the acoustic impedance difference between the inner container and the air;

[0172] Judge whether the actual reflection coefficient is abnormal based on the difference between the actual reflection coefficient and the ideal reflection coefficient, and obtain a first judgment result;

[0173] When the first judgment result indicates that the actual reflection coefficient is abnormal, the status information indicates that there is a defect in the second detection window.

[0174] In one embodiment, the processing unit 803 may specifically be used for:

[0175] Determine the acoustic impedance difference value between the inner container and the air, and determine the acoustic impedance sum value between the inner container and the air;

[0176] Determine the ideal reflection coefficient based on the ratio of the acoustic impedance difference value to the acoustic impedance sum value.

[0177] In one embodiment, the processing unit 803 may further be used for:

[0178] Perform time-domain analysis on the inner container echo data based on the time information and intensity information of all echo signals in the inner container echo data, and obtain first fluctuation information; the first fluctuation information characterizes the amplitude fluctuation situation of all echo signals;

[0179] Judge whether there is a second additional echo signal in the inner container echo data whose amplitude is lower than that of the second true echo signal based on the first fluctuation information, and obtain a second judgment result;

[0180] When the second judgment result indicates that there is a second additional echo signal in the inner container echo data, the status information indicates that there is a defect in the second detection window.

[0181] In one embodiment, the processing unit 803 may further be used to determine the attribute information of the defect existing in the second detection window; the attribute information includes the position of the defect; determining the attribute of the defect existing in the second detection window includes:

[0182] Based on the echo time of each second additional echo signal in the detection data, determine the distance between the defect in the second detection window and the probe, and obtain the defect position.

[0183] In one embodiment, the attribute information further includes a defect type; the processing unit may further be configured to:

[0184] Based on the first fluctuation information, determine the distribution characteristics of all second additional echo signals in the detection data to obtain the characteristic information of the defects in the second detection window;

[0185] Based on the characteristic information, determine the defect type of the second detection window.

[0186] In one embodiment, the detection unit 802 may further be configured to:

[0187] Based on the structural parameters of the inner container, determine the region where the surface stress of the inner container is concentrated to obtain a key region;

[0188] Configure the detection frequencies of the key region and other regions; the detection times of the key region are greater than those of other regions.

[0189] It should be noted that when the double-layer hydrogen storage bottle inner container defect detection device provided in the above embodiment performs double-layer hydrogen storage bottle inner container defect detection, only the above division of each program module is used for illustration. In practical applications, the above processing may be allocated to different program modules according to needs, that is, the internal structure of the device is divided into different program modules to complete all or part of the above-described processing. In addition, the double-layer hydrogen storage bottle inner container defect detection device provided in the above embodiment and the double-layer hydrogen storage bottle and its detection method embodiment belong to the same concept. For the specific implementation process, please refer to the method embodiment, which will not be elaborated here.

[0190] It should be noted that "first", "second", etc. are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0191] In addition, the technical solutions described in the embodiments of the present application may be combined arbitrarily without conflict.

[0192] The above is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application.

Claims

1. A method for detecting defects in the inner liner of a double-layer hydrogen storage bottle, characterized in that: The double-layer hydrogen storage bottle comprises an inner liner and an outer liner, and a vacuum port is arranged on the front side of the outer liner; the method comprises: Based on a preset detection path, the ultrasonic probe is moved from the first step window to the second step window; the ultrasonic probe is an air-coupled ultrasonic detection probe; Based on the preset detection frequency of the second step window, the second detection window is subjected to air-coupled ultrasonic detection by the ultrasonic probe to obtain detection data; the second detection window is the inner tank area detected by the ultrasonic probe at the current moment, and the second detection window corresponds to the position of the second step window; Based on the detection data, determining the status information of the second detection window; the status information indicates whether the second detection window has a defect; wherein, The detection data includes outer liner echo data and inner liner echo data obtained by air-coupled ultrasonic detection in all detection cycles; the detection cycle is the time between two ultrasonic pulses; the detection data is obtained by performing air-coupled ultrasonic detection on the second detection window using the ultrasonic probe at the preset detection frequency based on the second step window, including: In each detection cycle, after emitting an ultrasonic pulse, outer tank echo data and inner tank echo data returned based on the ultrasonic pulse are received in sequence; the outer tank echo data includes data of a first true echo signal reflected by the outer tank, and the inner tank echo data includes data of a second true echo signal reflected by the inner tank; and determining the status information of the second detection window based on the detection data comprises: determining the status information of the second detection window based on all inner tank echo data in the detection data.

2. The method according to claim 1, characterized in that Before moving the ultrasonic probe from the first stepping window to the second stepping window based on the preset detection path, the method further includes: Based on the preset step length of the ultrasonic probe, a grid surface of the outer gallbladder surface is constructed; the grid surface includes a plurality of first grids; Based on the area to be detected of the liner, determine a first grid corresponding to the area to be detected from the plurality of first grids to obtain a plurality of second grids; Based on the positions of the plurality of second grids, a detection path is configured.

3. The method according to claim 1, characterized in that The determining the state information of the second detection window based on all the inner tank echo data in the detection data includes: Based on all the inner tank echo data, determining the amplitude of the second true echo signal; Determining an actual reflection coefficient of the second detection window based on a difference between an amplitude of the second true echo signal and an amplitude of an ultrasonic pulse emitted during a current detection cycle; Determining an ideal reflection coefficient of the second detection window based on a difference in acoustic impedance between the inner liner and air; Based on the difference between the actual reflection coefficient and the ideal reflection coefficient, determining whether the actual reflection coefficient is abnormal, and obtaining a first determination result; When the first judgment result indicates that the actual reflection coefficient is abnormal, the status information indicates that the second detection window is defective.

4. The method according to claim 3, characterized in that The step of determining the ideal reflection coefficient of the second detection window based on the difference in acoustic impedance between the inner container and air includes: Determine the difference in acoustic impedance between the inner liner and the air, and determine the sum of the acoustic impedances of the inner liner and the air; An ideal reflection coefficient is determined based on a ratio of the acoustic impedance difference and the acoustic impedance sum.

5. The method according to claim 3, characterized in that: The method further comprises: Based on the time information and intensity information of all echo signals in the inner liner echo data, the inner liner echo data is subjected to time domain analysis to obtain first fluctuation information; the first fluctuation information represents the amplitude fluctuation of all echo signals; Based on the first fluctuation information, determining whether there is a second additional echo signal in the liner echo data whose amplitude is lower than the second true echo signal, and obtaining a second determination result; In a case where the second judgment result indicates that a second additional echo signal exists in the inner tube echo data, the state information indicates that a defect exists in the second detection window.

6. The method according to claim 5, characterized in that The method further includes determining attribute information of a defect existing in the second detection window; the attribute information includes a location of the defect; and determining the attribute of the defect existing in the second detection window includes: Based on the echo time of each second additional echo signal in the detection data, the distance between the defect and the probe in the second detection window is determined to obtain the defect position.

7. The method according to claim 6, characterized in that The attribute information also includes a defect type; and the method further includes: Based on the first fluctuation information, determining distribution characteristics of all second additional echo signals in the detection data, and obtaining characteristic information of defects in the second detection window; Based on the feature information, a defect type of the second detection window is determined.

8. The method according to any one of claims 1 to 7, characterized in that The method further comprises: Based on the structural parameters of the inner liner, determine the area where stress concentration is on the surface of the inner liner to obtain the key area; Configure the detection frequency of the key area and other areas; the detection frequency of the key area is greater than the detection frequency of other areas.

9. A double-layer hydrogen storage bottle liner defect detection device, characterized in that: The double-layer hydrogen storage bottle comprises an inner liner and an outer liner, and a vacuum port is arranged on the front side of the outer liner; the device comprises: A control unit, used for moving the ultrasonic probe from the first stepping window to the second stepping window based on a preset detection path; the ultrasonic probe is an air-coupled ultrasonic detection probe; A detection unit, configured to perform air-coupled ultrasonic detection on a second detection window using the ultrasonic probe based on a preset detection frequency of the second stepping window to obtain detection data; the second detection window is an inner tank area detected by the ultrasonic probe at the current moment, and the second detection window corresponds to a position of the second stepping window; A processing unit, configured to determine status information of the second detection window based on the detection data; the status information indicates whether the second detection window has a defect; wherein, The detection data includes the outer liner echo data and the inner liner echo data obtained by air-coupled ultrasonic detection in all detection cycles; the detection cycle is the time between two ultrasonic pulses; the detection unit is used to: In each detection cycle, after emitting an ultrasonic pulse, outer tank echo data and inner tank echo data returned based on the ultrasonic pulse are received in sequence; the outer tank echo data includes data of a first true echo signal reflected by the outer tank, and the inner tank echo data includes data of a second true echo signal reflected by the inner tank; and determining the status information of the second detection window based on the detection data comprises: determining the status information of the second detection window based on all inner tank echo data in the detection data.

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