Method and device for detecting defects of inner container of double-layer hydrogen storage bottle

Abstract

The invention discloses a double-layer hydrogen storage bottle liner defect detection method and device, and relates to the technical field of ultrasonic flaw detection. The method comprises the following steps: 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 coupling ultrasonic detection probe; based on the preset detection frequency of the second stepping window, performing air coupling ultrasonic detection on the second detection window by using the ultrasonic probe to obtain detection data; the second detection window is an inner container area detected by the ultrasonic probe at the current moment, and the second detection window corresponds to the second stepping window in position; determining state information of the second detection window based on the detection data; the state information indicates whether the second detection window has defects or not. According to the technical scheme provided by the invention, defect detection can be performed on the double-layer hydrogen storage bottle by utilizing ultrasonic waves.

Description

Technical Field

[0001] The present application relates to the field of ultrasonic flaw detection technology, and specifically to 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. The liquid hydrogen supply system has good integration and a volume-to-weight ratio of more than 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 corrosion during use; therefore, non-destructive testing (NDT) of hydrogen storage tanks is required to be performed regularly to ensure the safety of hydrogen storage tanks.

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

[0004] Therefore, how to overcome the above-mentioned technical problems and defects becomes a key issue that needs to be solved. Summary of the invention

[0005] The purpose of the present application is to provide a method and device for detecting defects in the inner liner of a double-layer hydrogen storage bottle, so as to solve the problems raised in the above-mentioned background technology and to realize defect detection of the double-layer hydrogen storage bottle using ultrasound.

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

[0007] The present application provides a method for detecting defects in a double-layer hydrogen storage bottle liner, the method comprising:

[0008] 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;

[0009] 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;

[0010] Based on the detection data, state information of the second detection window is determined; the state information indicates whether the second detection window has a defect.

[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 length of the ultrasonic probe, a grid surface of the outer gallbladder surface is constructed; the grid surface includes a plurality of first grids;

[0013] 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;

[0014] Based on the positions of the plurality of second grids, a detection path is configured.

[0015] In the above scheme, 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 preset detection frequency based on the second step window, the second detection window is subjected to air-coupled ultrasonic detection by the ultrasonic probe to obtain the detection data, including:

[0016] In each detection cycle, after emitting an ultrasonic pulse, the outer liner echo data and the inner liner echo data returned based on the ultrasonic pulse are received in sequence; the outer liner echo data includes data of a first true echo signal reflected by the outer liner, and the inner liner echo data includes data of a second true echo signal reflected by the inner liner;

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

[0018] Based on all the inner tube echo data in the detection data, the state information of the second detection window is determined.

[0019] In the above solution, the determining the state 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, determining the amplitude of the second true echo signal;

[0021] 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;

[0022] Determining an ideal reflection coefficient of the second detection window based on a difference in acoustic impedance between the inner liner and air;

[0023] 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;

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

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

[0026] 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;

[0027] An ideal reflection coefficient is determined based on a ratio of the acoustic impedance difference and the acoustic impedance sum.

[0028] In the above scheme, the method further comprises:

[0029] 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;

[0030] 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;

[0031] 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.

[0032] In the above solution, the method further includes determining attribute information of the defect existing in the second detection window; the attribute information includes the location of the defect; and 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, the distance between the defect and the probe in the second detection window is determined to obtain the defect position.

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

[0035] 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;

[0036] Based on the feature information, a defect type of the second detection window is determined.

[0037] In the above scheme, the method further comprises:

[0038] 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;

[0039] 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.

[0040] The present application also provides a double-layer hydrogen storage bottle inner liner defect detection device, 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:

[0041] 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;

[0042] 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;

[0043] A processing unit is used 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.

[0044] The double-layer hydrogen storage bottle inner liner defect detection method and device provided in the embodiment of the present application utilize air-coupled ultrasonic emission pulses and receive echo signals from the inner liner, so that the surface state of the inner liner's current detection area can be determined based on the characteristics of the echo signals, thereby achieving non-destructive flaw detection of the inner liner of the hydrogen storage device; further, since the outer liner and the inner liner area are associated, the probe can be accurately controlled to perform ultrasonic detection of the inner liner target area on the outer liner surface, thereby achieving accuracy and reliability of the detection position. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the structure of a double-layer hydrogen storage bottle provided in an embodiment of the present application;

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

[0047] Figure 3 A waveform diagram of a point defect in a double-layer hydrogen storage bottle liner defect detection method according to an embodiment of the present application;

[0048] Figure 4This is a schematic diagram of the echo when there is no defect in the second detection window in the double-layer hydrogen storage bottle liner defect detection method of the embodiment of the present application;

[0049] Figure 5 This is a schematic diagram of the echo when there is a primary defect in the second detection window in the double-layer hydrogen storage bottle liner defect detection method of the embodiment of the present application;

[0050] Figure 6 This is a schematic diagram of the echo when a secondary defect exists in the second detection window in the double-layer hydrogen storage bottle liner defect detection method of the embodiment of the present application;

[0051] Figure 7 This is a schematic diagram of the echo when there is a third-level defect in the second detection window in the double-layer hydrogen storage bottle liner defect detection method of the embodiment of the present application;

[0052] Figure 8 A schematic structural diagram of a double-layer hydrogen storage bottle liner defect detection device provided in an embodiment of the present application.

[0053] Description of main component symbols:

[0054] 11-outer liner; 12-inner liner; 13-connecting shaft; 14-sleeve. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] The embodiment of the present application provides a double-layer hydrogen storage bottle, which includes a liquid hydrogen bottle and a pipeline assembly;

[0057] like Figure 1As shown, the liquid hydrogen bottle includes an outer liner 11 and an inner liner 12, and a vacuum port is arranged at the front side of the outer liner 11; during the application of the liquid hydrogen bottle, the outer liner 11 and the inner liner 12 are vacuumed through the vacuum port to form a vacuum chamber between the two; and in the detection state, the vacuum port can be opened to make the space between the outer liner 11 and the inner liner 12 communicate with the external air to form an air chamber; the front end of the inner liner 12 is fixedly connected to the outer liner 11, and the rear end of the inner liner 12 is movably connected to the outer liner 11, specifically: the front and rear ends of the inner liner 12 are respectively provided with a connecting shaft 13, and the front and rear ends of the outer liner 11 are respectively provided with a sleeve 14, the connecting shaft 13 at the front end of the inner liner 12 is sealed and welded and fixed with the sleeve 14 at the front end of the outer liner 11, and the connecting shaft 13 at the rear end of the inner liner 12 is plugged and matched with the sleeve 14 at the rear end of the outer liner 11. The front side of the outer liner 11 is provided with a liquid hydrogen bottle vacuum port, and the space between the outer liner 11 and the inner liner 12 is vacuumed by an external vacuum device. In this embodiment, a support structure that extends the heat transfer path and reduces heat leakage of the system can be used between the connecting shaft 13 and the inner liner 12, and between the connecting shaft 13 and the sleeve 14. For details, please refer to the utility model patent recently applied by our company with authorization number CN218671590U and the invention name of an ultra-low temperature vacuum insulated pressure vessel with a double circuitous support structure.

[0058] The double-layer hydrogen storage bottle provided in the embodiment of the present application adopts an inner and outer double-layer structure design, which, on the one hand, meets the strength requirements of the on-board liquid hydrogen bottle, and on the other hand, can reduce the heat from the outside that leaks into the liquid hydrogen bottle through the pipeline, such as heat conduction, heat convection and heat radiation.

[0059] Based on the above double-layer hydrogen storage bottle structure, the embodiment of the present application provides a double-layer hydrogen storage bottle liner defect detection method, which is applied to electronic equipment, specifically industrial computers, personal computers, cloud servers, mobile terminals and other electronic devices. Figure 2 As shown, the method may include:

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

[0061] S202: Based on the preset detection frequency of the second step 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 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;

[0062] S203: 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.

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

[0064] In actual application, the outer tank surface can be gridded according to the moving step length of the probe, and 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 length of the ultrasonic probe, a grid surface of the outer gallbladder surface is constructed; the grid surface includes a plurality of first grids;

[0067] 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;

[0068] Based on the positions of the plurality of second grids, a detection path is configured.

[0069] In practical applications, the step length can be determined according to the transmission range of the ultrasonic probe in the outer chamber. For example, the step length can be set to 1 mm. The outer chamber surface is set to a regular scanning grid in units of the step length. For each grid point, ultrasonic waves are transmitted and reflected waves are received.

[0070] In actual application, the correspondence between the coordinate points of the inner liner and the outer liner is established according to the structural parameters of the inner liner and the outer liner, so as to determine the position of the inner liner corresponding to each grid point, realize the precise emission of ultrasonic waves to the target detection position of the inner liner, and improve the detection accuracy and reliability.

[0071] In actual application, all areas of the inner liner surface can be inspected, or only some areas can be inspected. For example, there are risk areas with high probability of defects on the inner liner surface, and there are also safe areas with low probability of defects. The risk areas can be inspected and monitored as areas to be inspected.

[0072] In one embodiment, the area to be detected of the inner container may be pre-configured; the configured area to be detected includes:

[0073] Stress concentration areas, including weld locations and geometric discontinuities (such as flange connections);

[0074] Corrosion-sensitive areas include the bottom and top of the inner tank and the pipe interface (such as the connection between the external connecting pipe and the inner tank).

[0075] In actual application, after determining the area to be detected of the inner liner, the position coordinates on the outer liner corresponding to the area to be detected are determined according to the correlation between the inner liner coordinates and the outer liner coordinates, as the target stepping area; then, a grid corresponding to the target stepping area is selected from the first grid as the second grid, and then a specific detection path is configured according to the position of each second grid. How to configure the path according to multiple path positions is an existing mature technology and will not be described in detail here.

[0076] After the detection path is configured, the corresponding second grids may be sequentially moved and detected according to the detection path, that is, S201 is executed.

[0077] In practical applications, the time required for detection in a second grid can be called a detection cycle, that is, the time period from the emission of an ultrasonic pulse in a second grid to the completion of all detections in the second grid and moving to the next second grid can be regarded as a detection cycle.

[0078] In actual application, the first step window corresponds to the second grid where the ultrasonic probe is currently located, and the second step window position corresponds to the second grid where the ultrasonic probe is located in the next detection cycle; in the initial state, the ultrasonic probe can be 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 the grid is completed, the ultrasonic probe is moved from the initial grid to the next second grid, that is, the ultrasonic probe is moved from the first step window to the second step window.

[0079] In practical applications, air-coupled ultrasound is a detection device used to propagate ultrasonic waves in the air.

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

[0081] In actual application, after moving to the position that needs 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 accordingly, but the detection efficiency will also decrease accordingly; 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 liner, determine the area where stress concentration is on the surface of the inner liner to obtain the key area;

[0084] 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.

[0085] Here, in the process of determining the key areas, a three-dimensional model of the liner can be established based on the structural parameters using finite element analysis software such as ANSYS, ABAQUS, and COMSOL. Then, a finite element analysis can be performed on the three-dimensional model to calculate the stress distribution of the liner 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 nonlinear static analysis; linear static analysis refers to the calculation of stress distribution under constant load (such as internal pressure), and nonlinear static analysis refers to nonlinear static analysis of nonlinear material behavior (such as plastic deformation).

[0088] Dynamic analysis can include fatigue analysis and thermal stress analysis; fatigue analysis can be understood as fatigue analysis of the cyclic loads experienced by the inner liner during use to predict the generation and development of fatigue cracks, while thermal stress analysis can be understood as thermal stress analysis based on the temperature changes of the inner liner to calculate the stress caused by the temperature gradient.

[0089] After the finite element analysis, the areas of stress concentration, i.e. the critical areas, can be identified by analyzing the finite element results.

[0090] In actual application, during the process of executing S202, the acquired detection data may include echo data of each detection cycle, and the echo data of each detection cycle includes echo data of the outer liner and the inner liner.

[0091] Based on this, in one embodiment, 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 transmitted ultrasonic pulses.

[0092] The step of 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, the outer liner echo data and the inner liner echo data returned based on the ultrasonic pulse are received in sequence; the outer liner echo data includes data of a first true echo signal reflected by the outer liner, and the inner liner echo data includes data of a second true echo signal reflected by the inner liner;

[0094] The determining, based on the detection data, the state information of the second detection window includes:

[0095] Based on all the inner tube echo data in the detection data, the state information of the second detection window is determined.

[0096] In actual application, after the ultrasonic pulse of the current detection cycle is emitted, the ideal echo time of the outer tube echo signal and the inner tube echo signal can be calculated according to the properties of the outer tube and the inner tube; 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] For example, the ideal echo time of the outer bladder can be determined using the following formula:

[0099]

[0100] Among them, t1 represents the ideal echo time of the outer shell, d1 represents the thickness of the outer shell, c1 represents the speed of sound in the outer shell, and t D Indicates the delay time;

[0101] The ideal echo time of the liner 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 liner and the outer liner, d2 represents the thickness of the inner liner, c air represents the speed of sound in air, and c2 represents the speed of sound in the inner tank.

[0104] Based on this, within the current detection cycle, after receiving the echo signal, the amplitude and receiving time of the different echo signals received can be observed according to the waveform scanning diagram of the echo signal, and the waveform received at the ideal echo time can be determined to be the real echo signal. Specifically, the real echo of the outer tank is received at the ideal echo time of the outer tank, that is, the first real echo signal, and the real echo of the inner tank is received 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 actual application, after the current detection window is fully detected 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, the data of the inner liner and the outer liner can be classified according to the ideal echo time of the inner liner and the outer liner, so as to analyze the echo data of the inner liner and the outer liner, that is, execute S203.

[0106] In actual applications, when the detection surface is uneven or the material properties are changed, the actual value of the emission coefficient of the detection surface will be significantly different from the ideal value calculated based on the material properties and geometric structure; therefore, in the process of executing S203, it is possible to judge whether there is an abnormality in the echo signal based on the difference between the actual reflection coefficient and the ideal reflection coefficient, thereby judging whether there is a defect in the current detection window.

[0107] Based on this, in one embodiment, determining the state 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, determining the amplitude of the second true echo signal;

[0109] 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;

[0110] Determining an ideal reflection coefficient of the second detection window based on a difference in acoustic impedance between the inner liner and air;

[0111] 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;

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

[0113] In actual application, when determining the amplitude of the second true echo signal based on all the inner liner echo data, the echo data of each detection cycle in all the inner liner echo data can be classified, and then the echo signal corresponding to the ideal echo time of each detection cycle 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 actual application, when determining the actual reflection coefficient of the second detection window based on the difference between the amplitude of the second real echo signal and the amplitude of the ultrasonic pulse emitted in the current detection period, the actual reflection coefficient of the inner liner in each detection period can be calculated first, and then the average value of the actual reflection coefficient of each period of the current detection window (i.e., the second detection window) can be used as the actual reflection coefficient of the second detection window.

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

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

[0117]

[0118] Among them, R0 represents the real-time reflection coefficient, d F Indicates the echo amplitude, d E Indicates the reflected wave amplitude.

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

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

[0121] 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;

[0122] An ideal reflection coefficient is determined based on a ratio of the acoustic impedance difference and the acoustic impedance sum.

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

[0124]

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

[0126] In actual application, after determining the actual reflection coefficient and the ideal reflection coefficient, it is determined whether the difference between the two exceeds the preset index threshold. If it exceeds, it indicates that there is a defect at that location. Here, the preset index threshold can be set according to historical data and specific application scenarios, and the embodiment of the present application does not limit this. For example, it is determined that |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 actual application, when there are small defects inside (such as tiny cracks or holes), the surface reflection coefficient may not be significantly changed, but additional echoes may be generated. At this time, the defects on the surface of the inner tank may be detected through the reflection coefficient. Therefore, in order to improve the reliability and accuracy of the test results, it is also possible to determine whether there are abnormal echoes near the main echo through time domain analysis, thereby determining whether there are defects at the current test location.

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

[0129] 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;

[0130] 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;

[0131] 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.

[0132] In actual application, based on the time information and intensity information of all echo signals in the inner liner echo data, the inner liner echo data is analyzed in the time domain. When the first fluctuation information is obtained, the amplitude distribution of the inner liner echo signal in each detection cycle can be determined to obtain the first fluctuation information; specifically, the time axis can be established according to the time of transmitting and receiving ultrasonic signals in the second detection window.

[0133] In actual application, based on the first fluctuation information, it is determined whether there is a second additional echo signal in the inner liner echo data with an amplitude lower than the second true echo signal. When the second judgment result is obtained, it can be determined whether there are additional echoes around each ideal echo on the time axis. If so, it means that there is a defect in the current detection window, otherwise, there is no defect.

[0134] In practice, when it is determined that there is a defect, the properties of the echo signal can also be determined based on the parameters of the echo signal.

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

[0136] In one embodiment, determining the attribute of the defect existing in the second detection window may include:

[0137] 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.

[0138] In actual application, 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 of the second additional echo position from the probe can be calculated, so that the depth of the inner liner surface defect can be determined according to the distance of the second additional echo position from the probe, the actual distance of the inner liner from the probe and the thickness of the inner liner.

[0139] In actual applications, the waveforms of different defects may show different characteristics. For example, the waveform of a point defect may show a sharper characteristic, such as Figure 3 As shown in the figure, the waveform of defects such as cracks and delamination may show a long time, and the peak is close to a broad platform. Therefore, the type of defect can be determined by the waveform of the second additional echo.

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

[0141] 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;

[0142] Based on the feature information, a defect type of the second detection window is determined.

[0143] In actual application, when determining the defect type of the second detection window based on the feature information, the defect type matching the feature information from preset defect types can be selected as the defect type of the second detection window based on the feature information.

[0144] In actual application, when the defect area is large, the received echo signal may not contain a true echo signal. Therefore, the size and type of the defect can be judged based on the echo situation of the ideal echo time.

[0145] Based on this, in one embodiment, the attribute information may further include a defect level; and the method may further include:

[0146] determining amplitude information of the second real echo and the second additional echo based on the first fluctuation information;

[0147] Based on the amplitude information, a defect level of the second detection window is determined.

[0148] In practical applications, the defect level can be understood as the level of defect size; when determining the defect level of the second detection window based on the amplitude information, it is possible to judge whether there is a second real echo and a second additional echo in the echo based on the amplitude information, and when the two exist at the same time, compare the sizes of the two, and then determine the defect level of the second detection window based on the comparison result.

[0149] In one embodiment, the defect level is divided into level one, level two and level three according to the defect size, and the defect areas from level one to level three decrease in sequence; and 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 currently detected is level one;

[0151] When the second true echo and the second additional echo exist in the echo at the same time, and the second true echo is smaller than the second additional echo, the defect level currently detected is level 2;

[0152] When the second true echo and the second additional echo exist in the echo at the same time, and the second true echo is greater than the second additional echo, the defect level currently detected is level three;

[0153] For example, Figure 4 The echo when there is no defect in the second detection window is shown. Figure 5 The echo showing the presence of a primary defect, Figure 6 Echoes showing the presence of secondary defects, Figure 7 The echoes with three levels of defects are shown, where T represents the transmitted wave, F represents the additional echo, and B represents the real echo.

[0154] Here, it should be noted that the above embodiment introduces the defect detection process of the inner liner. The detection data of each detection window also includes the echo data of the outer liner. Defect detection of the outer liner can be performed based on the echo data of the outer liner. The specific detection process can refer to the inner liner defect detection process.

[0155] In summary, the method for detecting defects in the inner liner of a double-layer hydrogen storage bottle provided in the embodiment of the present application utilizes air-coupled ultrasonic waves to transmit pulses and receive 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, thereby realizing non-destructive flaw detection of the inner liner of the hydrogen storage device; further, since the outer liner and the inner liner area are associated, the probe can be accurately controlled to perform ultrasonic detection of the target area of ​​the inner liner on the surface of the outer liner, thereby realizing the accuracy and reliability of the detection position.

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

[0157] The control unit 801 is used to move the ultrasonic probe from the first step window to the second step window based on a preset detection path; the ultrasonic probe is an air-coupled ultrasonic detection probe;

[0158] The detection unit 802 is used to perform 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; 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;

[0159] The processing unit 803 is 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.

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

[0161] 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;

[0162] 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;

[0163] Based on the positions of the plurality of second grids, a detection path is configured.

[0164] In one embodiment, 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 transmitted ultrasonic pulses; the detection unit 802 can be specifically used to:

[0165] In each detection cycle, after emitting an ultrasonic pulse, the outer liner echo data and the inner liner echo data returned based on the ultrasonic pulse are received in sequence; the outer liner echo data includes data of a first true echo signal reflected by the outer liner, and the inner liner echo data includes data of a second true echo signal reflected by the inner liner;

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

[0167] Based on all the inner tube echo data in the detection data, the state information of the second detection window is determined.

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

[0169] Based on all the inner tank echo data, determining the amplitude of the second true echo signal;

[0170] 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;

[0171] Determining an ideal reflection coefficient of the second detection window based on a difference in acoustic impedance between the inner liner and air;

[0172] 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;

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

[0174] In one embodiment, the processing unit 803 may be specifically configured to:

[0175] 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;

[0176] An ideal reflection coefficient is determined based on a ratio of the acoustic impedance difference and the acoustic impedance sum.

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

[0178] 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;

[0179] 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;

[0180] 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.

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

[0182] 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.

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

[0184] 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;

[0185] Based on the feature information, a defect type of the second detection window is determined.

[0186] In one embodiment, the detection unit 802 may also be used to:

[0187] 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;

[0188] 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.

[0189] It should be noted that: the double-layer hydrogen storage bottle liner defect detection device provided in the above embodiment only uses the division of the above program modules as an example when performing double-layer hydrogen storage bottle liner defect detection. In actual applications, the above processing can be assigned to different program modules as needed, that is, the internal structure of the device is divided into different program modules to complete all or part of the processing described above. In addition, the double-layer hydrogen storage bottle liner 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. The specific implementation process is detailed in the method embodiment and will not be repeated here.

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

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

[0192] The above description 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, state information of the second detection window is determined; the state information indicates whether the second detection window has a defect.

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 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, the outer liner echo data and the inner liner echo data returned based on the ultrasonic pulse are received in sequence; the outer liner echo data includes data of a first true echo signal reflected by the outer liner, and the inner liner echo data includes data of a second true echo signal reflected by the inner liner; The determining, based on the detection data, the state information of the second detection window includes: Based on all the inner tube echo data in the detection data, the state information of the second detection window is determined.

4. The method according to claim 3, 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.

5. The method according to claim 4, 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.

6. The method according to claim 4, 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.

7. The method according to claim 6, 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.

8. The method according to claim 7, 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.

9. The method according to any one of claims 1 to 8, 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.

10. 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 is used 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.

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