Acoustic emission signal monitoring method and system

Abstract

The present invention discloses a method for monitoring acoustic emission signals, comprising: directing the concave surface of a reflective portion within a sensor device toward a subject to be monitored; calculating the focal range of the reflective portion based on the frequency range of the acoustic emission wave output by the subject to be monitored, and setting a sensor module within the focal range; performing position matching between the sensor device and the subject to be monitored based on the effective detection range of the sensor device and the number of sensor devices configured; and locating the sound source based on the intensity of the acoustic wave signal obtained by each sensor device when the sensor module within the sensor device receives an acoustic wave signal formed by an acoustic emission wave propagated through a gas-liquid medium. The present invention is suitable for collecting acoustic wave signals propagated through gas and liquid, increasing the range and intensity of the collected signal, and enhancing the collection effect of weak sound signals. It has the characteristics of high sensitivity and signal-to-noise ratio, and improves the coverage and reliability of immersive acoustic emission detection.

Description

Technical Field

[0001] The present invention relates to the technical field of acoustic emission monitoring, and in particular to an acoustic emission signal monitoring method and system. Background Art

[0002] Acoustic emission (AE) technology is used to detect transient elastic waves generated by the rapid release of energy from localized sources of active defects in materials. Most materials exhibit AE during deformation and fracture. Furthermore, events unrelated to deformation and fracture mechanisms, such as fluid leakage, friction, impact, and combustion, can also produce AE. Generally, AE signals are too weak to be directly heard by the human ear and require the use of sensitive electronic instruments for detection. The frequency range of AE signals from various materials is wide, ranging from infrasound frequencies of a few hertz, acoustic frequencies of 20 Hz to 20 kHz, and ultrasonic frequencies of several megahertz. Furthermore, the amplitude of AE signals varies greatly, from microscopic dislocation motion of 10 meters to seismic waves of 1 meter. Effective detection and recording of AE signals requires sensitive electronic instruments to infer their sources and assess the material's condition. For example, instruments can be used to detect, record, and analyze AE signals, and to infer their sources. Therefore, sensors are crucial for the effective and efficient acquisition of AE signals.

[0003] Existing acoustic emission monitoring technology uses piezoelectric ceramic sensors, which are coupled to the test piece. After receiving the acoustic emission signal, the weak mechanical vibrations of the sound waves induce subtle vibrations on the ceramic surface. The piezoelectric crystal converts the weak mechanical vibrations into an electrical signal, which is amplified by a preamplifier. A filter removes mechanical noise, and the main amplifier further amplifies the signal for signal processing. Piezoelectric ceramic sensors are effective for monitoring solid-propagation acoustic emission signals. The acoustic wave signal must cross a detection threshold before it can be recorded and then located using multiple channels. However, it is difficult to effectively capture the acoustic emission signal by inducing micro-vibrations in the ceramic crystal when propagating through gas or solids. Furthermore, acoustic signals propagating through gas and liquid are significantly attenuated, and these sound source signals are weak and multidirectional. Furthermore, traditional piezoelectric sensors have only one sensing interface, which can easily miss acoustic wave signals propagating in other directions. In summary, using traditional piezoelectric ceramic sensors makes it difficult to fully capture the sound source signal, resulting in loss of sound source information, making it impossible to accurately identify and locate the sound source, and thus inaccurately assessing the material's structural condition.

[0004] Therefore, the prior art needs to provide an acoustic emission signal monitoring method that can be applied to gas and liquid media propagation. This method can have a signal acquisition effect with high sensitivity and sound intensity gain in gas and liquid environments, and can locate and identify the acoustic emission source. Summary of the Invention

[0005] In order to solve the above technical problems, an embodiment of the present invention provides an acoustic emission signal monitoring method, the method comprising: step 1, pointing the concave surface of the reflecting portion in the sensing device toward the object to be monitored; step 2, calculating the focal range of the reflecting portion according to the frequency range of the acoustic emission wave output by the object to be monitored, and setting the sensing module within the focal range, wherein the focal range is the optimal installation position within the effective detection range corresponding to the acoustic wave signal formed by the acoustic emission wave emitted at different positions of the object to be monitored by the sensing module; step 3, position matching the sensing device and the object to be monitored according to the effective detection range of the sensing device and the number of configured sensing devices; step 4, when the sensing module in the sensing device receives the acoustic wave signal formed by the acoustic emission wave propagated through the gas-liquid medium, the sound source is located according to the intensity of the acoustic wave signal obtained by each sensing device.

[0006] Preferably, the method further comprises: counting the number of times the sound wave signal is detected by the monitored area corresponding to each sensing device, and determining the sound source concentration using a preset time threshold.

[0007] Preferably, the method further includes: setting a sound source activity threshold value; determining different sound source damage level ranges based on the sound source activity threshold value; and determining the damage status corresponding to different areas to be monitored in the monitoring body using the different sound source damage level ranges based on the sound source concentration corresponding to different areas to be monitored.

[0008] Preferably, in the step four, it includes: determining the monitored area corresponding to the sensor device that receives the current sound wave signal as the sound source position, wherein when multiple sensor devices receive the current sound wave signal, the signal amplitudes of different monitored areas are compared, so as to determine the monitored area corresponding to the maximum amplitude as the sound source position.

[0009] Preferably, in step 2, the type of sensor module applicable to the current frequency range is determined based on the frequency range, and the sensor module types include narrowband sensors and broadband sensors; a spatial rectangular coordinate system is constructed with the vertex of the reflecting part as the origin and the depth direction of the reflecting part as the axis, and based on this, the focal range under the conditions of the corresponding sensor module type is calculated.

[0010] Preferably, when the current sensing module type is a narrowband sensor, the focal position is calculated according to the resonant frequency of the acoustic emission wave to be monitored; when the current sensing module type is a broadband sensor, the focal range is calculated according to the maximum frequency and minimum frequency of the acoustic emission wave to be monitored.

[0011] Preferably, the sensing module includes a plurality of sensor channels, the sensor channels include a plurality of piezoelectric crystals, and the piezoelectric crystals are configured as circular paraboloids.

[0012] Preferably, the effective detection range of the sensing device is calculated according to the following process: different experimental radii required for the attenuation test are set; with the sensing device as the origin, the propagation rays required for the test are drawn in the radial direction, and multiple test points are marked on the propagation rays based on the different experimental radii; standard sound waves are emitted at different test points respectively, and the corresponding signal amplitudes are recorded at the origin position, thereby drawing a signal amplitude curve that changes with the experimental radius; based on the signal amplitude curve and the preset signal amplitude threshold, the farthest distance at which the amplitude of the sound wave signal exceeds the signal amplitude threshold is determined; based on the farthest distance, the effective detection range is determined.

[0013] Preferably, the focal range is constructed as a cylindrical structure, the reflecting portion is constructed as a circular parabola, the base of the reflecting portion is made of thermoplastic resin material, and a metal tungsten film is deposited on the inner surface of the reflecting portion.

[0014] On the other hand, the present invention also provides an acoustic emission signal monitoring system, which is implemented using the method described above. The acoustic emission signal monitoring system is configured with one or more sensing devices, each sensing device comprising: a reflecting portion, which is constructed as a curved parabola, the concave surface of the curved parabola facing the object to be monitored, for reflecting the acoustic emission waves emitted by the object to be monitored so that the acoustic emission waves fall within the detection range of the sensing module; a sensing module, which is arranged within the focal range of the reflecting portion, for collecting the acoustic wave signals formed by the acoustic emission waves currently propagating through the gas-liquid medium, wherein the focal range is the optimal installation position within the effective detection range corresponding to the sensing module when collecting the acoustic wave signals formed by the acoustic emission waves emitted at different positions of the object to be monitored.

[0015] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0016] The present invention proposes an invasive acoustic focusing acoustic emission signal monitoring method. This method can determine the size of the reflector and the structure of the sensor module (sensor array structure) with better focusing effect according to the characteristic frequencies of different monitoring objects, wherein the reflector has the effects of ultra-small attenuation and high reflectivity. The immersion acoustic emission signal monitoring method proposed in the present invention can more effectively collect the sound wave signals propagated by gas and liquid, increase the collection signal range and enhance the signal strength, strengthen the collection effect of weak sound signals, and has the advantages of high sensitivity and signal-to-noise ratio, thereby improving the coverage of immersion acoustic emission detection and the reliability of the detection results. In addition, the present invention identifies and locates the sound source, narrows the sound source tracing range, and facilitates the judgment of the concentration of the acoustic emission source.

[0017] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0019] Figure 1 This is a step diagram of the acoustic emission signal monitoring method according to an embodiment of the present application.

[0020] Figure 2 This is a side view of the reflector in the acoustic emission signal monitoring method according to an embodiment of the present application.

[0021] Figure 3 Schematic diagram of the distribution effect of each sensor device in the acoustic emission signal monitoring method of an embodiment of the present application.

[0022] Figure 4 This is a schematic diagram of the principles of an example of the sound source localization process in the acoustic emission signal monitoring method of an embodiment of the present application.

[0023] Figure 5 This is a side view of the corresponding sensing device when the current sensing module type is a broadband sensor in the acoustic emission signal monitoring method of an embodiment of the present application.

[0024] Figure 6 This is a side view of the corresponding sensing device when the current sensing module type is a narrowband sensor in the acoustic emission signal monitoring method of an embodiment of the present application.

[0025] Figure 7 This is a schematic diagram of the overall structure of the acoustic emission sensor device according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings and examples, so that the present invention can fully understand how to apply technical means to solve technical problems and achieve technical effects, and thus implement the invention accordingly. It should be noted that, as long as no conflict exists, the various embodiments of the present invention and the various features of the embodiments can be combined with each other, and the resulting technical solutions are all within the scope of protection of the present invention.

[0027] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions. Also, although a logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in a different order than here.

[0028] Acoustic emission (AE) technology is used to detect transient elastic waves generated by the rapid release of energy from localized sources of active defects in materials. Most materials exhibit AE during deformation and fracture. Furthermore, events unrelated to deformation and fracture mechanisms, such as fluid leakage, friction, impact, and combustion, can also produce AE. Generally, AE signals are too weak to be directly heard by the human ear and require the use of sensitive electronic instruments for detection. The frequency range of AE signals from various materials is wide, ranging from infrasound frequencies of a few hertz, acoustic frequencies of 20 Hz to 20 kHz, and ultrasonic frequencies of several megahertz. Furthermore, the amplitude of AE signals varies greatly, from microscopic dislocation motion of 10 meters to seismic waves of 1 meter. Effective detection and recording of AE signals requires sensitive electronic instruments to infer their sources and assess the material's condition. For example, instruments can be used to detect, record, and analyze AE signals, and to infer their sources. Therefore, sensors are crucial for the effective and efficient acquisition of AE signals.

[0029] Existing acoustic emission monitoring technology uses piezoelectric ceramic sensors, which are coupled to the test piece. After receiving the acoustic emission signal, the weak mechanical vibrations of the sound waves induce subtle vibrations on the ceramic surface. The piezoelectric crystal converts the weak mechanical vibrations into an electrical signal, which is amplified by a preamplifier. A filter removes mechanical noise, and the main amplifier further amplifies the signal for signal processing. Piezoelectric ceramic sensors are effective for monitoring solid-propagation acoustic emission signals. The acoustic wave signal must cross a detection threshold before it can be recorded and then located using multiple channels. However, it is difficult to effectively capture the acoustic emission signal by inducing micro-vibrations in the ceramic crystal when propagating through gas or solids. Furthermore, acoustic signals propagating through gas and liquid are significantly attenuated, and these sound source signals are weak and multidirectional. Furthermore, traditional piezoelectric sensors have only one sensing interface, which can easily miss acoustic wave signals propagating in other directions. In summary, using traditional piezoelectric ceramic sensors makes it difficult to fully capture the sound source signal, resulting in loss of sound source information, making it impossible to accurately identify and locate the sound source, and thus inaccurately assessing the material's structural condition.

[0030] Therefore, in order to solve the above technical problems, the present invention proposes a method for monitoring acoustic emission signals. This method uses a focusing reflection structure to reflect acoustic emission waves propagating through different paths, thereby reducing the adsorption attenuation of acoustic wave signals propagating through air and liquid, and enhancing the acoustic wave reflection effect; then, a sensor array formed in an array manner is set at the focal position of the focusing reflection structure, and each sensor device is configured at a different monitoring area position in the monitored object (test piece to be tested), thereby enhancing the collection effect of the focused signal of the reflected sound wave; finally, the sound source of the acoustic emission wave after the focusing enhancement processing is positioned based on the principle that the emission position of the sound source falls into the corresponding sensor monitoring area. Therefore, the present invention locates the acoustic emission source based on the acoustic wave signal formed by the detected focused enhanced acoustic emission wave, and realizes more accurate detection and evaluation of the damage and fault conditions of the monitored object, thereby providing an acoustic focusing acoustic emission monitoring scheme suitable for gas-liquid medium transmission.

[0031] Example 1

[0032] The embodiment of the present invention first describes the structure of the acoustic emission signal monitoring system. The acoustic emission signal monitoring system is implemented using the following acoustic emission signal monitoring method. Specifically, the acoustic emission signal monitoring system includes multiple (acoustic emission) sensor devices with the same structure.

[0033] Figure 7 This is a schematic diagram of the overall structure of the acoustic emission sensor device according to the embodiment of the present application. Figure 7 The structure of the sensor device is described below. Figure 7 As shown, the acoustic emission sensor device includes a reflector and a sensor module. The reflector is constructed as a curved parabola, with the concave surface of the curved parabola facing the object to be monitored. The reflector is used to reflect the acoustic emission waves emitted by the object to be monitored so that the acoustic emission waves fall within the detection range of the sensor module. The sensor module is arranged within the focal range of the reflector and is used to collect the acoustic wave signals generated by the acoustic emission waves currently propagating through the gas-liquid medium. The focal range is the optimal installation position within the effective detection range corresponding to the sensor module when collecting the acoustic wave signals generated by the acoustic emission waves emitted at different positions of the object to be monitored.

[0034] Example 2

[0035] Based on the acoustic emission signal monitoring system described in the first embodiment above, the present invention further proposes an acoustic emission signal monitoring method. Figure 1 This is a step diagram of the acoustic emission signal monitoring method of the embodiment of the present application. Figure 1 The acoustic emission signal monitoring method of the present invention is described.

[0036] Step S110 directs the concave surface of the reflective portion within the sensor device toward the monitored object. To provide an acoustic emission signal monitoring method applicable to gas-liquid environments, the monitored object described in embodiments of the present invention is capable of emitting corresponding acoustic emission waves in different directions, which propagate through air and / or liquid media. In embodiments of the present invention, each monitored area within the monitored object must be exposed or partially exposed to the air and / or liquid environment.

[0037] Figure 2 FIG. 1 is a side view of the reflector in the acoustic emission signal monitoring method according to an embodiment of the present application. In step S110, (refer to Figure 2 ) The reflecting part in the sensing device has an acoustic focusing reflection function, which is used to reflect the acoustic emission waves transmitted through different paths so that the acoustic emission waves fall within the detection range of the sensing module, that is, the reflected sound waves are detected by the sensing module 20 set at the trigger focus.

[0038] Furthermore, in an embodiment of the present invention, the reflecting portion is a curved parabola structure. Preferably, the reflecting portion is a circular parabola. Figure 2 As shown, the dimensional design parameters of the reflector include at least: the radius of the circular opening of the parabola, the depth of the parabola, and the radius of the sphere to which the parabola of the reflector belongs. The aforementioned dimensional design parameters can be determined based on the size of the emission space of the object to be monitored, and each parameter must meet the following constraints:

[0039] R=(4h 2 +4a 2 ) / 8h (1)

[0040] Among them, R represents the radius of the sphere to which the reflecting part belongs, a represents the aperture of the parabola (i.e. half of the diameter of the circular opening), and h represents the depth of the parabola (i.e. the distance from the circular opening point to the vertex of the parabola).

[0041] Furthermore, the reflector base is made of a thermoplastic resin material, and a thin film of metal tungsten is deposited on the inner surface of the reflector. Specifically, the reflector base is made of a thermoplastic resin material such as polyvinyl chloride, polyethylene, polypropylene, or polyamide; and the thin film of metal tungsten ions is deposited on the inner surface of the reflector to reduce the material's absorption and attenuation of sound waves, thereby enhancing the sound wave reflection effect.

[0042] The preparation process of the reflective portion of the present invention is described below:

[0043] In step S101 (not shown), a resin arc-shaped shell is prepared by using a resin injection molding process and a pre-designed arc-shaped shell mold, thereby forming a reflective portion substrate.

[0044] Step S102 (not shown) uses a low-temperature plasma flow treatment process, using oxygen or air plasma technology to treat the inner surface of the curved resin shell obtained in step S101. In step S102, the oxygen or air plasma technology is set to a power range of 5 to 200 W, a treatment time of 1 to 30 minutes, a temperature range of -10 to 50°C, and a relative humidity of less than 93%, so that the tension of the inner surface of the curved resin shell after plasma treatment reaches a range of 68 to 72 dynes / cm. In this way, step S102 can increase the surface roughness and polarity of the resin material, making the deposited coating in the following steps more durable.

[0045] In step S103 (not shown), a layer of metal tungsten film is deposited on the inner surface of the resin arc-shaped shell whose inner surface has been roughened in step S102 by using metal vapor vacuum arc source technology. In actual application, in order to eliminate the contamination of the sample by large particles generated by the magnetic filtering arc source, it is necessary to install a magnetic filtering pipe and a focusing magnetic field that can be deflected 90° at the outlet of the MEVVA ion source in the magnetic filtering arc source plasma deposition system, so that the filtered ion beam can be injected or deposited onto the sample surface of the target chamber. In the magnetic filtering arc source plasma deposition system, metal tungsten is first used as the cathode, and the surface of the PET substrate is sputtered and cleaned with a voltage of 12kV and low-energy tungsten ions are implanted to improve the density of the film, and then the film is deposited. In order to make the deposited film have good adhesion, a negative voltage of 120V is applied to the PET substrate. In the embodiment of the present invention, in order to reduce the influence of the PET substrate on the film, the deposition thickness needs to be greater than 60nm.

[0046] In this way, after the arrangement of the reflector is completed, the process proceeds to step S120. Figure 1 As shown, step S120 calculates the focal range of the reflector based on the frequency range of the acoustic emission waves emitted by the monitored object, and places the sensor module within the focal range. The focal range is the optimal installation position within the effective detection range corresponding to the sensor module when collecting acoustic wave signals generated by the acoustic emission waves emitted at different locations of the monitored object.

[0047] In an embodiment of the present invention, the object to be monitored can be regarded as a collection (body) of sound source points at different locations inside. Since the reflector plays the role of reflecting sound waves and is constructed as a circular parabola structure, no matter at what angle the sound emission wave is emitted to the inner surface of the reflector, it can fall within the detection range of the sensor module corresponding to the focal range space of the reflector. Thus, in an embodiment of the present invention, it is necessary to calculate the installation position of the sensor module in the sensor device, that is, the focal range. Furthermore, since, in an embodiment of the present invention, the sensor module is used to receive and detect the sound wave signals formed by the sound emission waves transmitted from different paths, the spatial position in which the sensor module is to be arranged should be able to receive and detect the sound wave signals formed by the sound emission waves transmitted from different directions. In other words, in order to be able to receive the sound emission waves transmitted from different directions, the sensor module in the embodiment of the present invention is arranged within the focal range space of the reflector. Moreover, the focal range is the optimal installation position within the effective detection range corresponding to the sound wave signals formed by the sound emission waves emitted from different locations of the object to be monitored when the sensor module collects the sound wave signals formed by the sound emission waves emitted from different locations of the object to be monitored. In this way, it is ensured that the sensing part collects the full frequency band of the acoustic wave signal formed by the acoustic emission wave. Preferably, the focal space range is constructed as a cylindrical structure.

[0048] Furthermore, in order to target the application scenarios of sensing devices with different sound wave frequency ranges, in an embodiment of the present invention, the sensing module has two types, including: a narrowband sensor and a broadband sensor. When calculating the focal range, the installation position (focal range) of the sensing module using different sensor module types will be calculated based on the size of the frequency range of the sound emission wave output by the monitored object. Specifically, first, the type of sensing module applicable to the current frequency range is determined based on the frequency range of the sound emission wave output by the monitored object. In an embodiment of the present invention, if the difference between the maximum and minimum values ​​of the frequency range of the sound emission wave output by the monitored object is less than or equal to 10kHz, the current sensing module adopts a narrowband acoustic sensor. In addition, if the difference between the maximum and minimum values ​​of the frequency range of the sound emission signal output by the monitored object is greater than 10kHz, that is, the frequency fluctuation range of the sound wave signal is large, the current sensing module adopts a broadband acoustic sensor.

[0049] Then, after determining the sensor module type, it is necessary to construct a spatial rectangular coordinate system with the vertex of the reflector as the origin and the depth direction of the reflector as the axis. Based on this, the focal space range under the conditions of the corresponding sensor module type is calculated according to the intensity range and frequency range of the acoustic wave signal generated by the acoustic emission wave output by the monitored object. Figure 2In the current rectangular coordinate system ROZ, the origin is the vertex of the circular parabola reflector, the horizontal plane of the coordinate system is parallel to the plane of the reflector opening, and the Z axis of the coordinate system is the direction of the reflector's depth. Specifically, the geometric center point of the reflector's focal spatial range is located in the direction of the reflector's depth.

[0050] The following expression is used to calculate the corresponding focal space range under different sensor module types:

[0051]

[0052]

[0053]

[0054] Among them, z max Represents the distance between the focus and the vertex of the parabola of the reflecting part, f represents the frequency of the acoustic emission signal output by the monitored object, λ represents the wavelength of the acoustic wave corresponding to the current acoustic emission signal frequency, and c represents the wave velocity in the propagation medium. Among them, when the current sensing module type is a narrowband sensor, the current focus position is calculated based on the resonant frequency of the acoustic emission signal output by the monitored object. In other words, the resonant frequency of the acoustic emission signal output by the monitored object is used as the frequency of the acoustic emission wave output by the current monitored object, and is substituted into the above expressions (2) to (4), and the distance z between the geometric center point of the current focus space range and the vertex of the current reflective part parabola can be calculated. max , thereby determining the position of the focal space range under the current sensing module type conditions.

[0055] When the current sensor module type is a broadband sensor, the current focal range is calculated based on the maximum and minimum frequencies of the acoustic emission waves output by the monitored object. In other words, the maximum and minimum frequencies within the frequency range of the acoustic emission waves output by the monitored object are sequentially used as the frequencies of the acoustic emission waves output by the monitored object and substituted into the above expressions (2) to (4). The maximum and minimum focal positions corresponding to the corresponding maximum frequencies can be calculated, thereby forming the focal spatial range (length range) under the conditions of the current sensor module type.

[0056] Furthermore, after determining the position of the focal spatial range, it is necessary to further determine the arrangement of each sensor channel. In an embodiment of the present invention, the sensing module includes a plurality of sensor channels, and each sensor channel is arranged in sequence along the axial direction of the reflection module within the focal range. The sensing module is installed at the focal range through a bracket. The first end of the bracket is connected to the vertex of the reflection module, and the second end of the bracket extends along the axial direction of the reflection module. In an embodiment of the present invention, each (acoustic) sensor includes a plurality of piezoelectric crystals, and the plurality of piezoelectric crystals are arranged around the bracket in a circumferential direction at a preset interval, thereby forming an annular structure, further so that each sensor channel 21 is formed into a piezoelectric crystal array. Each piezoelectric crystal is constructed as a circular parabola structure, and the concave surface of the circular parabola faces the gas or liquid propagation medium side, so that the acoustic emission wave is focused again after receiving the corresponding acoustic emission wave.

[0057] Furthermore, when the current sensing module type is a narrowband resonant sensor, the thickness of each piezoelectric film is determined according to the resonant frequency of the acoustic emission wave emitted by the acoustic emission source of the monitored object. In the embodiment of the present invention, the piezoelectric crystal array in the narrowband resonant sensor is a single ring. That is, the narrowband resonant sensor is constructed to have one sensor channel, which is installed at the focal position of its reflection module (reference Figure 6 The shaded area in FIG is a side view of the sensing module composed of a narrow-band resonant sensor).

[0058] Furthermore, when the current sensor module type is a broadband sensor, the length of the entire sensor module is determined according to the length of the focal range under the conditions of the corresponding sensor module type. In the embodiment of the present invention, the piezoelectric crystal array in the broadband sensor is multi-ring. In other words, the broadband resonant sensor is constructed to have multiple sensor channels, which are arranged in sequence along the axial direction within the focal range of its reflection module (refer to Figure 5 The shaded area in FIG. 1 is a side view of a sensing module composed of broadband sensors, each of which is constructed as a three-layer ring-shaped piezoelectric crystal array).

[0059] Therefore, after the determination of the sensor module type, focus position and range is completed, the process proceeds to step S130. Figure 1 In step S130, the sensor device is matched with the object to be monitored according to the effective detection range of the sensor device and the number of the sensor devices configured.

[0060] When the monitoring area of ​​a monitored object is relatively large, the acoustic emission signal monitoring method of the present invention is difficult to detect acoustic emission waves from the entire object. Instead, it can only detect acoustic emission waves emitted from a portion of the object. In this case, to detect acoustic emission events for the entire object, it is necessary to configure multiple acoustic emission sensor devices for the object.

[0061] In step S130, the number of sensor devices to be deployed and the location of each sensor device must be determined. Specifically, the effective detection range of the sensor devices is calculated to ensure that the distances between adjacent sensor devices are consistent. Since each sensor device corresponds to a specific monitored area, all deployed sensor devices can monitor acoustic emission events across the entire monitored area in real time.

[0062] Therefore, in order to facilitate the implementation of subsequent sound source positioning, in an embodiment of the present invention, it is first necessary to determine the effective detection range of an acoustic emission sensor device; then, based on the current effective detection range, the number of acoustic emission sensor devices that need to be configured for the monitored object is determined; finally, with reference to the effective detection range and the number of configured sensor devices, the position matching of each acoustic emission sensor device with the monitored object is completed, thereby dividing the monitored object into multiple sound source areas. In this way, the present invention utilizes the position matching processing between the acoustic emission sensor device and the monitored object to achieve the configuration of an acoustic emission sensor device for each monitored area (sound source area) in the monitored object, so that no matter which sound source position in the monitored object emits the sound emission wave, it can be detected by one or more configured acoustic emission sensor devices.

[0063] The following is an explanation of the calculation process of the spacing between each sensor in the embodiment of the present invention. Step S1301 (not shown) sets the different experimental radii required for the attenuation test. In the embodiment of the present invention, the experimental results of the attenuation experiment are used to assist in calculating the effective detection range of the sensing device required for the current application scenario. In step S1301, it is necessary to set multiple experimental radii, such as: 0.5m, 1.0m, 1.5m, 2.0m, 3.0m, 4.0m, 6.0m, 9.0m, 12.0m and every 3.0m thereafter (15.0m, 18.0m, 21.0m...), etc. Then, step S1302 (not shown) takes a certain sensing device as the origin, draws the propagation ray required for the test in the radial direction, and marks multiple test points on the propagation ray based on the different experimental radii set in step S1301. Specifically, in step S1302, a ray is drawn along the radial direction with the origin sensing device as the starting point, and the ray is used as the signal propagation line required for the current test. Then, using each experimental radius data set in step S1301, based on the current starting point, the corresponding test point for each experimental radius data is marked on the propagation ray, thereby entering step 1303 (not shown).

[0064] Step 1303 (not shown) emits a standard sound wave at different test points and records the corresponding sound wave signal amplitude at the origin position, thereby drawing a signal amplitude curve that changes with the experimental radius. In step S1303, multiple standard signal emission experiments are implemented at each test point (emit multiple standard sound waves), and the signal amplitude results for different standard signal emission experiments collected at the origin are averaged, so that the average value is used as the amplitude of the sound wave signal for the current test point. For example: at each test point, an analog signal generator is used to excite a standard sound wave for measurement at regular intervals, and the excitation is continuous three times. The sound wave signal amplitudes collected at the origin position for these three times are recorded and the average value is calculated, and the average value is used as the sound wave signal amplitude of the current test point.

[0065] In step S1303, after obtaining the acoustic wave signal amplitude data corresponding to different test points, a signal amplitude characteristic curve that varies with the experimental radius is fitted based on these data, thereby entering step 1304 (not shown).

[0066] Step 1304 (not shown) determines the maximum distance at which the acoustic signal amplitude exceeds the threshold, i.e., the maximum radius corresponding to the signal peak at which the acoustic wave can be received, based on the signal amplitude curve obtained in step S1303 and a preset signal amplitude threshold, thereby proceeding to step S1305 (not shown). Step S1305 (not shown) determines the effective detection range of the sensing device based on the maximum distance (maximum radius) obtained in step S1304. Specifically, to enable acoustic emission waves of different frequencies to be detected by a smaller number of sensors and facilitate positioning, in this embodiment of the present invention, the spacing between adjacent sensing devices (effective detection distance) is 1.5 times the peak radius.

[0067] Furthermore, after obtaining the effective detection range of the aforementioned sensor devices, it is necessary to position-match each sensor device. Specifically, since the distance between adjacent sensor devices is equal, in this embodiment of the present invention, it is necessary to set the monitored area corresponding to each sensor device to be the same. The monitored area corresponding to each sensor device refers to the area within which the current sensor device can detect effective acoustic emission waves. Figure 3 Schematic diagram of the distribution effect of each sensor device in the acoustic emission signal monitoring method of the embodiment of the present application. Figure 3 As shown, the area to be monitored of each sensor device is a regular hexagon or the area to be monitored of each sensor device is a regular hexagon.

[0068] Thus, through the above steps S110 to S130, all preparations for entering the acoustic emission signal monitoring phase are completed, and the process proceeds to step S140. In step S140, when the sensing modules in the sensing devices receive the acoustic wave signals formed by the waves propagating through the gas-liquid medium, the sound source is located based on the intensity of the acoustic wave signals obtained by each sensing device.

[0069] In step S140, based on the positional relationship between each of the aforementioned sensing devices and the focal range, and the position matching results between each of the sensing devices and the monitoring area, after one or more sensing modules in the sensing device receive a sound wave signal formed by an acoustic emission wave emitted by a sound source in a certain monitoring area, the monitoring area corresponding to the sensing device that receives the current sound wave signal is directly determined as the area to which the sound source position belongs, that is, the sound source is within the monitoring area.

[0070] Furthermore, in step S140, referring to Figure 4The monitoring area corresponding to a single sensor device can be further divided into multiple sub-areas (for example, six). If multiple sensor devices receive the current acoustic signal, the amplitudes of the acoustic signals collected by the monitored areas corresponding to different sensor devices are compared pairwise. The sub-area within the monitoring area corresponding to the largest amplitude is then directly identified as the sound source location. This monitoring sub-area is then the location of the sound source. Figure 4 This is a schematic diagram of the principles of an example of the sound source localization process in the acoustic emission signal monitoring method of an embodiment of the present application. Figure 4 The principle of the sound source attribution process when two adjacent sensor devices receive the same sound wave signal is demonstrated. For example: when sensor device 1, sensor device 3 and sensor 4 receive the sound wave signal formed by the same acoustic emission wave, if the amplitude of the sound wave signal received by sensor device 3 is greater than the amplitude of the sound wave signal received by sensor device 1, and the amplitude of the sound wave signal received by sensor device 1 is greater than the amplitude of the sound wave signal received by sensor device 4, and the amplitude of the sound wave signal received by sensor device 3 is greater than the amplitude of the sound wave signal received by sensor device 4, then at this time, it is determined that the current sound source position is in the 3>1 sub-area within the monitoring area corresponding to sensor device 1; if the amplitude of the sound wave signal received by sensor device 4 is greater than the amplitude of the sound wave signal received by sensor device 3, and the amplitude of the sound wave signal received by sensor device 1 is greater than the amplitude of the sound wave signal received by sensor device 3, and the amplitude of the sound wave signal received by sensor device 1 is greater than the amplitude of the sound wave signal received by sensor device 4, then at this time, it is determined that the current sound source position is in the 1>4 sub-area within the monitoring area corresponding to sensor device 1.

[0071] Furthermore, once the present invention enters the formal acoustic emission signal monitoring process, it continuously evaluates the activity of each monitoring area within the monitored body according to the method described in step S140 above. Thus, the present invention amplifies and analyzes the sound sources at different monitoring points and calculates the number of acoustic wave signals detected by the sensor devices corresponding to different monitoring areas within a preset time period (H).

[0072] In this way, the present invention will count the number of times each sensor device records the detection of the sound wave signal in step S150 (not shown), and use the preset time period threshold to obtain the number of valid sound wave signals detected in each monitoring area within the preset time threshold, thereby obtaining the sound source concentration data of the monitoring body in different monitoring areas. In this embodiment of the present invention, when the current sensor device detects the sound source to which the sound wave signal belongs and the sound source happens to be in the monitoring area corresponding to the current sensor device, the sound wave signal emitted by the belonging area is a valid sound wave signal, and an event about the detection of the valid sound wave signal in the current monitoring area is recorded once. If the current sensor device detects the sound wave signal, but the current sound source is not in the monitoring area corresponding to the current sensor device, then there is no need to record the event about the detection of the valid sound wave signal in the current monitoring area.

[0073] It should be noted that the present invention does not specifically limit the value of the preset time period threshold, and those skilled in the art may set it based on actual needs. In the embodiment of the present invention, the preset time period threshold is 1 hour. Thus, the present invention calculates the number of valid acoustic emission signals H detected per hour within the monitoring areas of different sensors of the monitored object.

[0074] Furthermore, in order to amplify and analyze the above-mentioned sound source concentration data, the present invention performs a graded evaluation on the sound source concentration data corresponding to each sensor signal monitoring area in the monitoring body. Specifically, first, the present invention sets a sound source activity threshold value K. Then, based on the set sound source activity threshold value K, different sound source damage level ranges are determined. Finally, based on the sound source concentration data corresponding to different sensor signal monitoring areas (the number of effective acoustic emission signals H detected per hour), different sound source damage level ranges are used to determine the damage status corresponding to different monitored areas in the monitored body. Among them, the sound source damage level is divided into four levels: no activity (no damage has occurred in the monitoring area), low activity (minor damage is occurring in the monitoring area), medium activity (moderate damage is occurring in the monitoring area), and high activity (severe damage is occurring in the monitoring area). Table 1 shows the sound source concentration data ranges corresponding to different sound source damage levels.

[0075] Table 1 Sound source damage level evaluation table

[0076] Sound source concentration level Number of signals detected per hour in the monitoring area Damage status assessment level I H≤K No activity II K<H≤10K Low activity III 10K<H≤100K Medium activity IV H>100K High activity

[0077] In this way, the acoustic emission signal monitoring method based on acoustic focusing of the present invention can more effectively collect gas-liquid propagation sound wave signals and identify and locate the sound source, thereby narrowing the sound source tracing range and facilitating the judgment of the concentration of the acoustic emission source.

[0078] The following provides examples of applying the acoustic emission signal monitoring method of the present invention to different application scenarios.

[0079] Example 3

[0080] The acoustic emission signal monitoring method described in this invention is applied to the monitoring scenario of corrosion and leakage of storage tank bottom plates. The specific process is as follows:

[0081] 1. Scenario Analysis: Traditional tank floor acoustic emission detection is performed using piezoelectric sensors placed on the outer wall of the tank. However, as the size of storage tanks increases, this monitoring method is unable to detect corrosion leakage acoustic emission signals in the center of the tank bottom due to the weak intensity of the acoustic emission signal of corrosion leakage and the influence of attenuation. The acoustic emission signal monitoring method described in the present invention can be used to monitor corrosion leakage of tank floors. A sensing device including a reflector and a sensor module can be placed into the tank, and one or more sensor arrays can be used to form a sensing module. The sensing device and the sensors on the outer wall of the tank jointly monitor the corrosion leakage status of the tank floor. The acoustic wave signal generated by the corrosion leakage acoustic emission wave has an amplitude range of 33 to 70 dB and a wide frequency range. A broadband acoustic focusing acoustic emission sensor is used to form the sensing module.

[0082] Figure 5 This is a side view of the corresponding sensor device in the acoustic emission signal monitoring method of the embodiment of the present application when the current sensor module type is a broadband sensor. Figure 5 , illustrating the different stages of the acoustic emission signal monitoring method.

[0083] 2. Preparation stage of acoustic emission signal monitoring method:

[0084] The reflective portion is prepared according to the method described in steps S101 to S103 above, wherein the substrate is made of a thermoplastic resin material such as polyvinyl chloride, polyethylene, polypropylene, or polyamide, and a metal tungsten ion film is deposited on the inner surface to reduce the adsorption and attenuation of sound waves by the material and enhance the sound wave reflection effect.

[0085] Next, a sensor array is arranged on the bottom plate of the tank, and the monitoring area is divided by calculating the effective detection range of the sensor.

[0086] 3. Monitoring stage of acoustic emission signal monitoring method:

[0087] After the sensor device receives the acoustic signal formed by the acoustic emission wave, it locates the sound source. At the same time, the concentration of the sound source in each monitoring area is analyzed to determine the corrosion damage.

[0088] The acoustic emission signal monitoring method described in this invention allows for online assessment of corrosion and leakage detection on tank floors without requiring production halts or tank openings, offering unparalleled advantages over other technical methods. This method comprehensively monitors the acoustic emission signals generated by tank floor corrosion and leakage. Furthermore, the focused action of the sensor device generates more and stronger acoustic signals, improving the accuracy of identifying the source of corrosion and leakage, thereby preventing accidents.

[0089] Example 4

[0090] The acoustic emission signal monitoring method described in the present invention is applied to the monitoring scenario of a low-speed bearing system. The specific process is as follows:

[0091] 1. Scenario Analysis

[0092] Low-speed bearing systems are generally used for rotating equipment with a speed of 0 to 120 RPM. Since the fault frequency of the bearing is approximately 0 to 5 Hz, the vibration analyzer has a blind spot for analyzing vibration frequencies below 5 Hz. Even very high-end vibration analyzers have great difficulty analyzing vibrations below 2 Hz, and there is a blind spot. Therefore, the acoustic emission method described in the present invention can be used to monitor it. In a low-speed bearing system, for a ball / rolling element failure through an outer ring defect point, the monitoring frequency is 0.4 × the number of rolling elements × the shaft speed. Therefore, for the current monitoring scenario, the fault frequency that needs to be monitored is relatively fixed, and a narrow-band resonant sensor can be used to form a sensing module.

[0093] Figure 6 This is a side view of the corresponding sensor device in the acoustic emission signal monitoring method of the embodiment of the present application when the current sensor module type is a narrowband sensor. Figure 6 , illustrating the different stages of the acoustic emission signal monitoring method.

[0094] 2. Preparation stage of acoustic emission signal monitoring method:

[0095] The reflective portion is prepared according to the method described in steps S101 to S103 above, wherein the substrate is made of a thermoplastic resin material such as polyvinyl chloride, polyethylene, polypropylene, or polyamide, and a metal tungsten ion film is deposited on the inner surface to reduce the adsorption and attenuation of sound waves by the material and enhance the sound wave reflection effect.

[0096] Next, corresponding sensor devices are arranged at the machine pumps at different locations to form a sensor device array, and by calculating the effective monitoring range of the sensor device, the machine pumps at different locations are divided into monitoring areas of each sensor device according to the ownership of the sensor device.

[0097] 3. Monitoring stage of acoustic emission signal monitoring method:

[0098] After the sensor device receives the acoustic signal formed by the acoustic emission wave, it locates the sound source. At the same time, it conducts a concentration analysis of the pump sound source in each monitoring area to determine the operating status of the pump.

[0099] The embodiment of the present invention proposes an invasive acoustic focusing acoustic emission signal monitoring method and system. The method and system can determine the size of the reflector and the structure of the sensor module (sensor array structure) with better focusing effect according to the characteristic frequencies of different monitoring objects, wherein the reflector has the effects of ultra-small attenuation and high reflectivity. The immersion acoustic emission signal monitoring method proposed in the present invention can more effectively collect the sound wave signals propagated by gas and liquid, increase the collection signal range and enhance the signal strength, strengthen the collection effect of weak sound signals, and has the advantages of high sensitivity and signal-to-noise ratio, thereby improving the coverage range of immersion acoustic emission detection and the reliability of the detection results. In addition, the present invention identifies and locates the sound source, narrows the sound source tracing range, and facilitates the judgment of the concentration of the acoustic emission source.

[0100] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by anyone skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

[0101] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should extend to equivalent substitutions of these features understood by those skilled in the relevant art. It should also be understood that the terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0102] References in this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment" or "an embodiment" in various places throughout this specification do not necessarily refer to the same embodiment.

[0103] Although the embodiments disclosed above are for facilitating understanding of the present invention, the contents described are merely embodiments adopted for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art of the present invention may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope of the present invention. However, the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. An acoustic emission signal monitoring method applied to an acoustic emission signal monitoring system, characterized in that: The acoustic emission signal monitoring system is configured with one or more sensing devices, each of which includes: a reflector configured as a curved parabola, with the concave surface of the curved parabola facing the object to be monitored, for reflecting the acoustic emission waves emitted by the object to be monitored so that the acoustic emission waves fall within the detection range of the sensor module; The sensing module is arranged within the focal range of the reflecting portion and is used to collect the acoustic wave signal formed by the acoustic emission wave currently propagating through the gas-liquid medium, wherein the focal range is the optimal installation position within the effective detection range corresponding to the sensing module when collecting the acoustic wave signal formed by the acoustic emission wave emitted at different positions of the monitored object, wherein, The sensing module is mounted at the focal range via a bracket, wherein a first end of the bracket is connected to the vertex of the reflecting portion, and a second end of the bracket extends along the axial direction of the bracket of the reflecting portion. The sensing module includes a plurality of sensor channels arranged in sequence along the axial direction of the bracket, wherein the sensor channel includes a plurality of piezoelectric crystals. The plurality of piezoelectric crystals in the same sensor channel surround the bracket in a circumferential direction at preset intervals to form an annular structure. Each piezoelectric crystal is constructed as a circular parabola structure, and the concave surface of the circular parabola faces the gas or liquid propagation medium side, thereby focusing the acoustic emission wave again after receiving the corresponding acoustic emission wave. The acoustic emission signal monitoring method includes: Step 1: Direct the concave surface of the reflective portion of the sensor device toward the object to be monitored; Step 2: Calculating the focal range of the reflector according to the frequency range of the acoustic emission waves output by the monitored object, and placing the sensor module within the focal range, which includes: determining the type of sensor module applicable to the current frequency range according to the frequency range, wherein the sensor module types include narrowband sensors and broadband sensors. When a narrowband resonant sensor is used, the sensor module has one sensor channel; when a broadband resonant sensor is used, the sensor module has multiple sensor channels, and these sensor channels are arranged sequentially along the axial direction of the bracket within the focal range of the reflector module; Step 3: Position matching between the sensor device and the object to be monitored based on the effective detection range of the sensor device and the number of sensor devices configured; Step 4: When the sensing modules in the sensing devices receive the acoustic wave signals formed by the acoustic emission waves propagating through the gas-liquid medium, the sound source is located according to the intensities of the acoustic wave signals obtained by each sensing device.

2. The method according to claim 1, characterized in that The method further comprises: The number of times the acoustic wave signal is detected by each sensing device in the monitored area is counted, and the sound source concentration is determined using a preset time threshold.

3. The method according to claim 2, characterized in that The method further comprises: Set the sound source activity threshold; Determining different sound source damage level ranges according to the sound source activity threshold value; According to the sound source concentration corresponding to different to-be-monitored areas, the damage states corresponding to different to-be-monitored areas in the to-be-monitored body are determined using the different sound source damage level ranges.

4. The method according to any one of claims 1 to 3, characterized in that In the step 4, it includes: The monitored area corresponding to the sensor device that receives the current sound wave signal is determined as the sound source position. When multiple sensor devices receive the current sound wave signal, the signal amplitudes of different monitored areas are compared, so that the monitored area corresponding to the maximum amplitude is determined as the sound source position.

5. The method according to any one of claims 1 to 4, characterized in that In the step 2, A spatial rectangular coordinate system is constructed with the vertex of the reflecting part as the origin and the depth direction of the reflecting part as the axis, based on which the focal range under the condition of the corresponding sensor module type is calculated.

6. The method according to claim 5, characterized in that When the current sensor module type is a narrowband sensor, the focus position is calculated according to the resonant frequency of the acoustic emission wave to be monitored; When the current sensor module type is a broadband sensor, the focal range is calculated according to the maximum frequency and the minimum frequency of the acoustic emission wave to be monitored.

7. The method according to any one of claims 1 to 6, characterized in that The sensing module includes a plurality of sensor channels, each of which includes a plurality of piezoelectric crystals. The piezoelectric crystals are configured as circular paraboloids.

8. The method according to any one of claims 1 to 7, characterized in that The effective detection range of the sensor device is calculated according to the following process: Set different experimental radii required for attenuation testing; Taking the sensing device as the origin, drawing a propagation ray required for the test along a radial direction, and marking a plurality of test points on the propagation ray based on the different experimental radii; Standard sound waves are emitted at different test points, and the corresponding signal amplitudes are recorded at the origin, thereby drawing a signal amplitude curve that changes with the experimental radius; Determining, based on the signal amplitude curve and a preset signal amplitude threshold, a maximum distance at which the amplitude of the acoustic wave signal exceeds the signal amplitude threshold; The effective detection range is determined according to the maximum distance.

9. The method according to any one of claims 1 to 8, characterized in that The focal range is constructed as a cylindrical structure, the reflecting part is constructed as a circular parabola, the base of the reflecting part is made of thermoplastic resin material, and a metal tungsten film is deposited on the inner surface of the reflecting part.

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