An acoustic emission sensing device and its preparation method

Abstract

This invention discloses an acoustic emission sensing device, comprising: a reflection module, which is constructed as an arc-shaped paraboloid with its concave surface facing the object to be monitored, for reflecting 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; and a sensing module, which is disposed within the focal range of the reflection module, for acquiring the acoustic wave signal formed by the acoustic emission waves propagating through the gas-liquid medium. The focal range is the optimal installation position within the effective detection range corresponding to the sensing module acquiring acoustic wave signals formed by acoustic emission waves emitted from different locations on the object to be monitored. This invention is applicable to the acquisition of acoustic wave signals propagating through gas and liquid media, increasing the range and intensity of the acquired signal, enhancing the acquisition effect of weak acoustic signals, and featuring high sensitivity and signal-to-noise ratio, thereby improving the coverage and reliability of immersion acoustic emission detection.

Description

Technical Field

[0001] This invention relates to the field of acoustics and materials science, and in particular to an acoustic emission sensing device and its fabrication method. Background Technology

[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. Additionally, events unrelated to deformation and fracture mechanisms, such as fluid leakage, friction, impact, and combustion, also produce AE. Generally, AE signals are very weak and inaudible to the human ear, requiring sensitive electronic instruments for detection. The frequency range of AE signals varies widely across different materials, from infrasound (a few hertz), acoustic frequencies (20 Hz–20 kHz), to ultrasonic frequencies (several MHz); furthermore, the amplitude of AE signals varies greatly, from microscopic dislocation movements of 10 m to seismic waves on the order of 1 m. Effective detection and recording of AE signals using sensitive electronic instruments are essential for inferring the AE source and assessing the material's condition. Examples include using instruments to detect, record, and analyze AE signals and inferring the AE source. Therefore, sensors are crucial for the effective and efficient acquisition of AE signals.

[0003] Current acoustic emission monitoring technology utilizes piezoelectric ceramic sensors coupled to the test piece. Upon receiving the acoustic emission signal, the weak mechanical vibration of the sound wave induces a weak vibration on the ceramic surface. The piezoelectric crystal converts this weak mechanical vibration into an electrical signal, which is amplified by a preamplifier, filtered to remove mechanical noise, and then further amplified by a main amplifier for signal processing. Piezoelectric ceramic sensors are reasonably effective at monitoring acoustic emission signals propagating through solids; the sound wave signal must cross a detection threshold to be recorded, requiring multi-channel localization. However, acoustic emission waves propagating through gases or liquids attenuate significantly, making it difficult to induce micro-vibrations in the ceramic crystal and effectively capture the acoustic emission signal. These sound sources are characterized by their weakness and multidirectional nature. Furthermore, traditional piezoelectric sensors have only one sensing interface, easily losing sound wave signals propagating in other directions. In summary, using traditional piezoelectric ceramic sensors makes it difficult to comprehensively acquire sound source signals, leading to the loss of sound source information and inaccurate identification and localization of the sound source, resulting in inaccurate evaluation of the material's structural state.

[0004] Therefore, the prior art needs to provide an acoustic emission sensing device that can be used for propagation in gaseous and liquid media, and that can achieve high sensitivity and high sound intensity gain in signal acquisition in both gaseous and liquid environments. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an acoustic emission sensing device. The device includes: a reflection module configured as an arc-shaped paraboloid, with its concave surface facing the object to be monitored, used to reflect acoustic emission waves emitted by the object, so that the acoustic emission waves fall within the detection range of the sensing module; and a sensing module disposed within the focal range of the reflection module, used to collect acoustic wave signals formed by acoustic emission waves propagating through a gas-liquid medium. The focal range is the optimal installation position within the effective detection range corresponding to the sensing module's collection of acoustic wave signals formed by acoustic emission waves emitted from different locations on the object to be monitored.

[0006] Preferably, the reflection module is constructed as a circular parabolic structure.

[0007] Preferably, the sensing module is mounted on the focal area via a bracket, wherein the first end of the bracket is connected to the vertex of the reflection module, the second end of the bracket extends along the axial direction of the reflection module, and the sensing module includes a plurality of sensor channels arranged sequentially along the axial direction.

[0008] Preferably, the sensing module is selected from narrowband sensors and broadband sensors, wherein the type of sensing module is determined according to the frequency range of the acoustic emission wave emitted by the acoustic emission source of the current monitored object.

[0009] Preferably, when the current sensing module type is a narrowband sensor, the focal position is calculated based on the resonant frequency of the sound wave to be monitored; when the current sensing module type is a wideband sensor, the focal range is calculated based on the maximum and minimum frequencies of the sound wave to be monitored.

[0010] Preferably, the substrate of the reflective module is made of thermoplastic resin material, and a tungsten thin film is deposited on the inner surface of the reflective module.

[0011] Preferably, the sensor channel includes a plurality of piezoelectric crystals, which are arranged at preset intervals around the bracket in the circumferential direction.

[0012] Preferably, when the current sensing module type is a narrowband sensor, the narrowband sensor is configured as a single sensor channel; when the current sensing module type is a wideband sensor, the wideband sensor is configured as multiple sensor channels.

[0013] On the other hand, the present invention also provides a preparation method for preparing the acoustic emission sensing device as described above. The preparation method includes the following steps: preparing a reflective module with an arc-shaped parabolic structure and facing the concave surface of the reflective module toward the object to be monitored; setting the sensing module within the focal range of the reflective module to collect the acoustic wave signal formed by the acoustic emission wave 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 from different positions of the object to be monitored.

[0014] Preferably, the step of preparing the reflective module with the arc-shaped parabolic structure includes: preparing a resin arc-shaped shell using a resin injection molding process; treating the inner surface of the resin arc-shaped shell using oxygen or air medium plasma technology; and depositing a thin film of tungsten metal on the inner surface of the resin arc-shaped shell using metal vapor vacuum arc source technology, thereby forming the reflective module.

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

[0016] This invention proposes an acoustic emission sensing device and its fabrication method. The device is applied to gas-liquid propagating acoustic signals, such as gas leaks and corrosion leaks from tank bottom plates. It allows for the determination of reflective module size and sensing module structure (sensor array structure) with better focusing effect based on the characteristic frequencies of different monitored objects. The reflective part exhibits ultra-low attenuation and high reflectivity. The immersion acoustic emission signal monitoring method proposed in this invention can more effectively acquire gas-liquid propagating acoustic signals, increase the acoustic signal acquisition range and enhance signal strength, improve the acquisition effect of weak acoustic signals, and has the advantages of high sensitivity and signal-to-noise ratio, thereby improving the coverage and reliability of immersion acoustic emission detection results.

[0017] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a schematic diagram of the overall structure of the acoustic emission sensing device according to an embodiment of this application.

[0020] Figure 2 This is a side view of the reflection module 10 in the acoustic emission sensing device according to an embodiment of this application.

[0021] Figure 3 This is a side view of the acoustic emission sensing device in an embodiment of this application when the current sensing module type is a broadband sensor.

[0022] Figure 4 This is a side view of the acoustic emission sensing device in an embodiment of this application when the current sensing module type is a narrowband sensor.

[0023] Figure 5 This is a step diagram illustrating the fabrication method of the acoustic emission sensing device according to an embodiment of this application. Detailed Implementation

[0024] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0025] Furthermore, the steps illustrated in the flowcharts 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 flowcharts, in some cases the steps shown or described may be performed in a different order than that shown here.

[0026] 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. Additionally, events unrelated to deformation and fracture mechanisms, such as fluid leakage, friction, impact, and combustion, also produce AE. Generally, AE signals are very weak and inaudible to the human ear, requiring sensitive electronic instruments for detection. The frequency range of AE signals varies widely across different materials, from infrasound (a few hertz), acoustic frequencies (20 Hz–20 kHz), to ultrasonic frequencies (several MHz); furthermore, the amplitude of AE signals varies greatly, from microscopic dislocation movements of 10 m to seismic waves on the order of 1 m. Effective detection and recording of AE signals using sensitive electronic instruments are essential for inferring the AE source and assessing the material's condition. Examples include using instruments to detect, record, and analyze AE signals and inferring the AE source. Therefore, sensors are crucial for the effective and efficient acquisition of AE signals.

[0027] Current acoustic emission monitoring technology utilizes piezoelectric ceramic sensors coupled to the test piece. Upon receiving the acoustic emission signal, the weak mechanical vibration of the sound wave induces a weak vibration on the ceramic surface. The piezoelectric crystal converts this weak mechanical vibration into an electrical signal, which is amplified by a preamplifier, filtered to remove mechanical noise, and then further amplified by a main amplifier for signal processing. Piezoelectric ceramic sensors are reasonably effective at monitoring acoustic emission signals propagating through solids; the sound wave signal must cross a detection threshold to be recorded, requiring multi-channel localization. However, acoustic emission waves propagating through gases or liquids attenuate significantly, making it difficult to induce micro-vibrations in the ceramic crystal and effectively capture the acoustic emission signal. These sound sources are characterized by their weakness and multidirectional nature. Furthermore, traditional piezoelectric sensors have only one sensing interface, easily losing sound wave signals propagating in other directions. In summary, using traditional piezoelectric ceramic sensors makes it difficult to comprehensively acquire sound source signals, leading to the loss of sound source information and inaccurate identification and localization of the sound source, resulting in inaccurate evaluation of the material's structural state.

[0028] Therefore, to solve the above-mentioned technical problems, this invention proposes an acoustic emission sensing device and its preparation method. This device employs a focusing reflection structure to reflect acoustic emission waves propagating along different paths, thereby reducing the adsorption attenuation of acoustic emission waves propagating through air and liquid, and enhancing the sound wave reflection effect. Then, a sensor array is arranged in an array at the focal point of the focusing reflection structure, with each sensor positioned at a different monitoring point in the gas or liquid within the object to be monitored (test piece), thereby enhancing the acquisition effect of the focused signal of the reflected sound wave. Thus, the acoustic emission sensing device of this invention can achieve high sensitivity and high sound intensity gain signal acquisition in gaseous and liquid environments.

[0029] Example 1

[0030] Figure 1 This is a schematic diagram of the overall structure of the acoustic emission sensing device according to an embodiment of this application. The following is in conjunction with... Figure 1 The acoustic emission sensing device described in this invention will be explained. For example... Figure 1 As shown, the acoustic emission sensing device includes a reflection module 10 and a sensing module 20.

[0031] In this embodiment of the invention, the reflection module 10 is constructed as an arc-shaped parabola, with the concave surface of the arc-shaped parabola facing the object to be monitored. The reflection module 10 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 sensing module 20. Figure 2This is a side view of the reflection module 10 in the acoustic emission sensing device according to an embodiment of this application. The reflection module 10 has an acoustic focusing and reflection function, which is used to reflect acoustic emission waves that have traveled through different paths, so that the reflected sound waves are superimposed on the sensing module 20 set at the trigger focus and detected.

[0032] Furthermore, to provide an acoustic emission sensing device suitable for gaseous and liquid media environments, the object to be monitored in the embodiments of the present invention can emit corresponding acoustic emission waves in different directions, and these acoustic emission waves propagate through air and / or liquid media. In the embodiments of the present invention, the parts of the object to be monitored that need to be detected need to be exposed or partially exposed to air and / or liquid media environments.

[0033] Furthermore, in this embodiment of the invention, the reflection module 10 is constructed as a circular parabolic surface. For example... Figure 2 As shown, the dimensional design parameters of the reflective module 10 include at least: the radius of the parabolic circular opening, the depth of the parabola, and the radius of the sphere to which the parabolic surface of the reflective module belongs. These dimensional design parameters can be determined based on the size of the emission space of the object to be monitored, and each parameter needs to satisfy the following constraints:

[0034] R = (4h) 2 +4a 2 ) / 8h (1)

[0035] Where R represents the radius of the sphere to which the reflector module belongs, a represents the diameter of the parabolic opening (i.e., half the diameter of the circular opening), and h represents the depth of the parabolic surface (i.e., the distance from the point of the circular opening to the vertex of the parabolic surface).

[0036] Furthermore, the substrate of the aforementioned reflective module 10 is made of thermoplastic resin material, and a tungsten metal thin film is deposited on the inner surface of the reflective module 10. Specifically, the substrate of the reflective module 10 is made of thermoplastic resin materials such as polyvinyl chloride, polyethylene, polypropylene, and polyamide; the inner surface of the reflective module 10 is made of a tungsten metal ion thin film deposited to reduce the adsorption and attenuation of sound waves by the material and enhance the sound wave reflection effect.

[0037] In addition, the sensing module 20 is located within the focal range of the reflection module 10 and is used to collect the acoustic emission signal formed by the acoustic emission wave propagating through the gas-liquid medium after the reflection module 10 reflects the acoustic emission wave emitted by the object to be monitored.

[0038] In this embodiment of the invention, the object to be monitored can be considered as a collection (body) of sound source points at different internal locations. Since the reflective module 10 plays the role of sound wave reflection and is constructed as a circular parabolic structure, regardless of the angle at which the sound emission wave is emitted towards the inner surface of the reflective module 10, it can fall within the detection range of the sensing module 20 corresponding to the focal range space of the reflective module 10. Thus, in this embodiment of the invention, it is necessary to calculate the installation position of the sensing module 20 within the sensing device, i.e., the focal range. Furthermore, since in this embodiment of the invention, the sensing module 20 is used to receive and detect the sound wave signals formed by sound emission waves transmitted from different paths, the spatial position required for the sensing module 20 should be able to receive and detect the sound wave signals formed by sound emission waves transmitted from different directions. That is to say, in order to receive sound emission waves transmitted from different directions, the sensing module 20 in this embodiment of the invention is located within the focal range space of the reflective module 10. Furthermore, the focal range is the optimal installation position within the effective detection range corresponding to the acoustic wave signals formed by the acoustic emission waves emitted from different locations on the monitored object when the sensing module 10 is collecting them. This ensures that the sensing module 20 can collect the acoustic wave signals formed by the acoustic emission waves across the entire frequency band. Preferably, the focal space is constructed as a cylindrical structure.

[0039] Furthermore, in order to address application scenarios of sensing devices with different sound wave frequency ranges, the embodiments of the present invention provide two types of sensing modules: narrowband sensors and broadband sensors. When calculating the focal range, the installation location range (focal range) of the sensing modules using different sensor module types is calculated based on the frequency range of the sound emission waves emitted by the sound emission source to be monitored.

[0040] Specifically, firstly, based on the frequency range of the acoustic emission wave emitted by the acoustic emission source to be monitored, the type of sensing module suitable for the current frequency range is determined. In this embodiment of the invention, if the difference between the maximum and minimum values ​​of the frequency range of the acoustic emission wave emitted by the acoustic emission source to be monitored is less than or equal to 10 kHz, then the current sensing module uses a narrowband acoustic sensor. Conversely, if the difference between the maximum and minimum values ​​of the frequency range of the acoustic emission wave emitted by the acoustic emission source to be monitored is greater than 10 kHz, i.e., the frequency fluctuation range of the acoustic signal is large, then the current sensing module uses a broadband acoustic sensor.

[0041] Then, after determining the sensor module type, a spatial rectangular coordinate system needs to be constructed with the vertex of the reflection module 10 as the origin and the depth direction (axial direction) of the reflection module 10 as the axis. Based on this, the focal spatial range under the corresponding sensor module type condition is calculated according to the intensity range and frequency range of the acoustic emission wave emitted by the acoustic emission source to be monitored. (Reference) Figure 2In the current Cartesian coordinate system ROZ, the origin is the vertex of the circular parabolic reflective module 10. The horizontal plane of the coordinate system is parallel to the plane containing the opening of the reflective module 10, and the Z-axis of the coordinate system is the direction of the depth of the reflective module 10. Furthermore, the geometric center of the focal space of the reflective module 10 is located in the depth direction of the reflective module 10.

[0042] The focal space range for different sensor module types is calculated using the following expression:

[0043]

[0044]

[0045]

[0046] Among them, z max Let f represent the distance between the focal point and the vertex of the parabolic surface of the reflector, f represent the frequency of the acoustic emission wave emitted by the acoustic emission source to be monitored, λ represent the wavelength of the current acoustic emission wave, and c represent the wave velocity in the propagation medium. When the current sensing module type is a narrowband sensor, the current focal point position is calculated based on the resonant frequency of the acoustic emission wave emitted by the acoustic emission source to be monitored. That is, by taking the resonant frequency of the acoustic emission wave emitted by the acoustic emission source to be monitored as the frequency of the current acoustic emission wave emitted by the acoustic emission source to be monitored, and substituting it into the above expressions (2) to (4), the distance z between the geometric center point of the current focal point spatial range and the vertex of the parabolic surface of the current reflecting module 10 can be calculated. max This determines the location of the focal space range under the current sensor module type.

[0047] When the current sensing module type is a broadband sensor, the current focal range is calculated based on the maximum and minimum frequencies of the acoustic emission waves emitted by the acoustic emission source to be monitored. That is, by substituting the maximum and minimum frequencies of the frequency range of the acoustic emission waves emitted by the acoustic emission source to be monitored into the above expressions (2) to (4), the maximum and minimum focal positions corresponding to the corresponding extreme frequencies can be calculated, thus forming the focal space range (length range) under the current sensing module type conditions.

[0048] Furthermore, after determining the location of the focal space, it is necessary to determine the arrangement of each sensor channel. The sensing module 20 includes several sensors 21, each constructed as a cylinder. Since the sensing module 20 includes several sensor channels 21, these channels are arranged sequentially along the axial direction of the reflecting module 10 within the focal space. The sensing module 20 is mounted at the focal space via a bracket. The first end of the bracket is connected to the vertex of the reflecting module 10, and the second end of the bracket extends along the axial direction of the reflecting module 10.

[0049] Furthermore, in this embodiment of the invention, each (acoustic) sensor channel 21 includes multiple piezoelectric crystals. These piezoelectric crystals are mounted at predetermined intervals around a support in the circumferential direction, forming a ring structure. This further ensures that each sensor channel 21 is formed as a piezoelectric crystal array. Each piezoelectric crystal is constructed as a circular parabolic structure, with the concave surface of the parabolic surface facing the gas or liquid propagation medium, thereby refocusing the acoustic wave after receiving it.

[0050] 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 to be monitored. In this embodiment of the invention, the piezoelectric crystal array within the narrowband resonant sensor is a single ring. That is, the narrowband resonant sensor is constructed to have a sensor channel 21, which is mounted at the focal position of its reflection module 10. Figure 4 This is a side view of the acoustic emission sensing device according to an embodiment of this application, when the current sensing module type is a narrowband sensor. Figure 4 As shown, Figure 4 The shaded area in the image shows a side view of the sensing module 20, which consists of a narrowband resonant sensor.

[0051] Furthermore, when the current sensing module type is a broadband sensor, the length of the entire sensing module 20 is determined according to the length of the focal range under the corresponding sensing module type conditions. In this embodiment of the invention, the piezoelectric crystal array within the broadband sensor is multi-ringed. That is, the broadband resonant sensor is constructed to have multiple sensor channels 21, which are arranged sequentially along the axial direction within the focal range of its reflection module 10. Figure 3 This is a side view of the acoustic emission sensing device according to an embodiment of this application, when the current sensing module type is a broadband sensor. Figure 3 As shown, Figure 3 The shaded area shows a side view of the sensing module 20, which consists of broadband sensors. Each broadband sensor in the current sensing module 20 is constructed as a three-layer ring-shaped piezoelectric crystal array.

[0052] Example 2

[0053] Based on the above embodiment one, after determining the sensor module type, focal position, and range, it is also necessary to perform position matching between the acoustic emission sensing device and the monitoring range corresponding to the object to be monitored. When the area to be monitored within the object to be monitored is large, the acoustic emission sensing device described in this invention is insufficient to detect the acoustic emission waves of the entire object; it can only detect the acoustic emission waves emitted from a portion of the object. In this case, to complete the detection of acoustic emission events for the entire object to be monitored, multiple acoustic emission sensing devices need to be configured for that object.

[0054] Therefore, to facilitate subsequent sound source localization, in this embodiment of the invention, the effective detection range of an acoustic emission sensor is first determined. Then, based on the current effective detection range, the number of acoustic emission sensors required for the monitored object is determined. Finally, referring to the effective detection range and the number of sensors, the positions of each acoustic emission sensor and the monitored object are matched to divide the monitored object into multiple sound source regions. In this way, by utilizing the position matching process between the acoustic emission sensor and the monitored object, this invention enables the configuration of one acoustic emission sensor for each monitored region (sound source region) within the monitored object. Regardless of which sound source location within the monitored object emits an acoustic emission wave, it can be detected by the configured acoustic emission sensors.

[0055] Thus, the acoustic emission sensing device of the present invention can improve the coverage and reliability of immersion acoustic emission detection.

[0056] Example 3

[0057] Based on the acoustic emission sensing device described in Embodiment 1 or Embodiment 2 above, the present invention also proposes a preparation method. This method is used to prepare the aforementioned acoustic emission sensing device. Figure 5 This is a step diagram illustrating the fabrication method of the acoustic emission sensing device according to an embodiment of this application.

[0058] like Figure 5 As shown, step S510 involves preparing a reflective module 10 with an arc-shaped parabolic structure, and aligning the concave surface of the reflective module 10 towards the object to be monitored. Then, step S520 involves placing the sensing module 20 within the focal range of the reflective module 10 to collect the acoustic wave signal formed by the acoustic emission wave propagating through the gas-liquid medium. The focal range is the optimal installation position within the effective detection range corresponding to the sensing module 20 when collecting acoustic wave signals formed by acoustic emission waves emitted from different locations on the object to be monitored.

[0059] The fabrication process of the reflective module 10 described in step S510 is explained below. Step S511 (not shown) involves fabricating a resin arc-shaped shell using resin injection molding. Then, step S512 uses oxygen or air-medium plasma technology to treat the inner surface of the resin arc-shaped shell. Finally, step S513 uses metal vapor vacuum arc source technology to deposit a thin tungsten film on the inner surface of the resin arc-shaped shell, thereby forming the reflective module 10.

[0060] For example: First, in step S511, a resin arc-shaped shell is prepared using a resin injection molding process and a pre-designed arc-shaped shell mold, thereby forming the substrate of the reflective module 10.

[0061] Step S512 involves using a low-temperature plasma flow treatment process, employing oxygen or air-medium plasma technology to treat the inner surface of the resin arc-shaped shell obtained in step S511. In step S512, the power of the oxygen or air-medium plasma technology is set to the range of 5–200W, the treatment time to 1–30 minutes, the temperature range to -10–50℃, and the relative humidity to <93%, so that the surface tension of the inner surface of the resin arc-shaped shell after plasma treatment reaches 68–72 dynes / cm. Thus, step S512 increases the surface roughness and polarity of the resin material, making the deposited coating in the following steps more robust.

[0062] In step S512, a thin film of tungsten metal is deposited on the inner surface of the resin arc-shaped shell, which has undergone inner surface roughening treatment in step S512, using metal vapor vacuum arc source technology. In practical applications, to eliminate the contamination of the sample by large particles generated by the magnetically filtered arc source, a magnetically filtered channel capable of deflection by 90° and a focusing magnetic field need to be installed at the MEVVA ion source outlet within the magnetically filtered arc source plasma deposition system. This allows the filtered ion beam to be injected or deposited onto the sample surface in the target chamber. In the magnetically filtered arc source plasma deposition system, tungsten metal is first used as the cathode, and a 12kV voltage is used to sputter-clean and implant low-energy tungsten ions onto the PET substrate surface to improve the film's density. Then, film deposition is performed. To ensure good adhesion of the deposited film, a negative voltage of 120V is applied to the PET substrate. In this embodiment of the invention, to reduce the influence of the PET substrate on the film, the deposition thickness needs to be greater than 60nm.

[0063] The method for manufacturing an acoustic focusing sensor described in this invention can determine a sensor structure with better focusing effect for different characteristic frequencies of the monitored object, and the reflective structure has the effects of ultra-low attenuation and high reflectivity.

[0064] Example 4

[0065] The acoustic emission sensing device and its preparation method described in this invention are applied to a monitoring scenario for corrosion leakage of the bottom plate of a storage tank. The specific process is as follows:

[0066] First, based on the size of the acoustic emission space of the object to be monitored, the dimensions of the reflection module 10, suitable for the current application scenario, are determined. When the opening radius a = 120 mm, the chord height h = 60 mm, and the parabolic radius R = 75 mm.

[0067] Then, the reflective module is prepared according to the method described in steps S510 to S520 above. The substrate is a thermoplastic resin material such as polyvinyl chloride, polyethylene, polypropylene, or polyamide. The inner surface is deposited with a thin film of tungsten ions to reduce the adsorption and attenuation of sound waves by the material and enhance the sound wave reflection effect.

[0068] Tests showed that: First, at the same location 100mm away from the same acoustic sensor, an acoustic emission signal with a frequency of 30kHz and an intensity of 60dB, received after reflection by a focusing structure with a tungsten ion film coating on its inner surface, showed an 8dB increase in amplitude compared to a focusing structure without such a coating, indicating a significantly enhanced focusing effect. Second, at the same location 200mm away from the same acoustic sensor, an acoustic emission signal with a frequency of 60kHz and an intensity of 70dB, received after reflection by a focusing structure with a tungsten ion film coating on its inner surface, showed a 10dB increase in amplitude compared to a focusing structure without such a coating, indicating a significantly enhanced focusing effect. Third, at the same location 300mm away from the same acoustic sensor, an acoustic emission signal with a frequency of 150kHz and an intensity of 80dB, received after reflection by a focusing structure with a tungsten ion film coating on its inner surface, showed a 15dB increase in amplitude compared to a focusing structure without such a coating, indicating a significantly enhanced focusing effect.

[0069] Next, the sensor module type is determined based on the frequency range of the acoustic emission signal emitted by the current monitoring object.

[0070] Finally, a sensor array was installed on the bottom plate of the storage tank, and the positions of each sensor were matched with the monitoring points.

[0071] The acoustic emission sensing device described in this invention can be used to detect corrosion leaks in the bottom plate of storage tanks without shutting down production or opening the tank. This invention can comprehensively monitor acoustic emission signals of corrosion leaks in the bottom plate of storage tanks, and under the focusing effect of the sensor, obtain more and stronger acoustic emission signals, improving the accuracy of identifying the sound source of corrosion leaks and preventing accidents.

[0072] This invention proposes an immersion-type acoustic focusing acoustic emission sensing device and its fabrication method. This device is applied to gas-liquid propagating acoustic signals, such as gas leaks and corrosion leaks from tank bottom plates. It allows for the determination of reflector size and sensing module structure (sensor array structure) for better focusing effects based on the characteristic frequencies of different monitored objects. The reflector exhibits ultra-low attenuation and high reflectivity. The immersion-type acoustic emission signal monitoring method proposed in this invention can more effectively acquire gas-liquid propagating acoustic signals, increasing the acquisition signal range and enhancing signal strength, improving the acquisition effect of weak acoustic signals. It has the advantages of high sensitivity and signal-to-noise ratio, thereby improving the coverage and reliability of immersion-type acoustic emission detection results.

[0073] 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 variations or substitutions that can be easily conceived by those 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 determined by the scope of the claims.

[0074] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0075] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0076] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An acoustic emission sensing device, characterized in that, The acoustic emission sensing device is applied to gas-liquid propagation acoustic signal applications such as gas leaks and corrosion leaks from tank bottom plates, including: The reflection module is constructed as an arc-shaped parabolic surface, with the concave surface facing the object to be monitored. It is used to reflect acoustic emission waves emitted from different locations in the object to be monitored and propagating through different paths, so that the acoustic emission waves fall into the detection range of the sensing module. The sensing module, positioned within the focal range of the reflecting module, is used to acquire the acoustic wave signal formed by the acoustic emission wave propagating through the gas-liquid medium. The focal range is the optimal installation position within the effective detection range corresponding to the sensing module's acquisition of acoustic wave signals formed by acoustic emission waves emitted from different locations on the monitored object. The sensing module is mounted at the focal point via a bracket. The first end of the bracket is connected to the vertex of the reflecting module, and the second end of the bracket extends along the axial direction of the reflecting module's diameter. The sensing module includes several sensor channels arranged sequentially along the axial direction of the bracket. Each sensor channel includes multiple piezoelectric crystals. Multiple piezoelectric crystals within the same sensor channel are arranged in a ring around the bracket at preset intervals, forming a circular structure. Each piezoelectric crystal is constructed as a circular parabolic structure, with the concave surface of the parabola facing the gas or liquid propagation medium, thereby refocusing the acoustic emission wave after receiving it. The appropriate sensor module type is determined based on the frequency range of the acoustic emission wave emitted by the acoustic emission source of the object to be monitored. The sensor module types include narrowband sensors and broadband sensors. When using a narrowband resonant sensor, the sensor module has one sensor channel. When using a broadband resonant sensor, the sensor module has multiple sensor channels. These sensor channels are arranged sequentially along the axial direction of the support within the focal range of the reflection module.

2. The apparatus according to claim 1, characterized in that, The reflection module is constructed as a circular parabolic structure.

3. The apparatus according to claim 1, characterized in that, When the current sensing module type is a narrowband sensor, the focal position is calculated based on the resonant frequency of the sound wave to be monitored; When the current sensing module type is a broadband sensor, the focal range is calculated based on the maximum and minimum frequencies of the sound wave to be monitored.

4. The apparatus according to claim 1 or 2, characterized in that, The substrate of the reflective module is made of thermoplastic resin material, and a tungsten thin film is deposited on the inner surface of the reflective module.

5. A preparation method, characterized in that, The preparation method is used to prepare the acoustic emission sensing device as described in any one of claims 1 to 4, and the preparation method includes the following steps: A reflective module with an arc-shaped parabolic structure is prepared, and the concave surface of the reflective module is oriented towards the object to be monitored; The sensing module is positioned within the focal range of the reflection module to collect the acoustic wave signal formed by the acoustic emission wave propagating through the gas-liquid medium. 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 from different positions of the monitored object.

6. The method according to claim 5, characterized in that, The steps in fabricating a reflective module with an arc-shaped parabolic structure include: A resin arc-shaped outer shell is prepared using resin injection molding. The inner surface of the resin arc-shaped shell is treated with oxygen or air-medium plasma technology; The reflective module is formed by depositing a thin film of tungsten metal on the inner surface of the resin arc-shaped shell using metal vapor vacuum arc source technology.

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