An ultrasonic phased-patch sensor and structural health monitoring system

Abstract

The application discloses an ultrasonic phased patch sensor and a structural health monitoring system, and relates to the technical field of structural health nondestructive testing.The ultrasonic phased patch sensor comprises a flexible circuit board, a piezoelectric sensing array, a positive electrode signal layer and a negative electrode shielding layer.The positive and negative electrodes of the array elements of the piezoelectric sensing unit are arranged on the same side of the flexible circuit board, the negative electrode shielding layer is formed into a multilayer circuit by penetrating through a through hole to extend to the other side of the flexible circuit board, and is separated from the positive electrode signal layer, so that the cost is low, the parasitic capacitance between the generated signal and the object to be measured and the electromagnetic interference between the signal lines are effectively reduced, and the electronic noise of the signal is reduced and the imaging signal-to-noise ratio is improved.The application solves the problems of large signal noise and many imaging noise points in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of structural health nondestructive testing, and more particularly to: 1. An ultrasonic phased patch sensor, which has the characteristics of low cost, flexibility and adhesion to curved structures; 2. A structural health monitoring system based on the ultrasonic phased patch sensor, which supports long-term continuous health monitoring of structures in service with defects. BACKGROUND

[0002] In the petrochemical and energy industries, many key pressure-bearing structures (such as pressure vessels, pipelines and reaction devices) continue to serve under the condition of defects if the remaining strength still meets the safety requirements after the serviceability evaluation. Such "wounded operation" structures still face the risks of stress, fatigue, corrosion, etc. during subsequent service. In order to realize the continuous safety monitoring of such structures, ultrasonic array technology that can be installed for a long time is considered as a promising solution.

[0003] In addition to petrochemical systems, similar long-term monitoring needs also exist in other key infrastructure fields, especially in scenarios where maintenance space is limited and downtime is costly. For example, in civil engineering, embedded permanently installed ultrasonic sensors have been applied to bridge girders and concrete bridge deck slabs to achieve long-term monitoring of stress redistribution, crack propagation and freeze-thaw damage through guided wave technology, verifying the feasibility of ultrasonic methods for structural health monitoring in complex outdoor environments. Similarly, in the renewable energy field, wind turbine generators (especially composite blades, towers and foundation structures) are subjected to long-term alternating loads, which are prone to interlaminar delamination, fatigue cracks and corrosion damage.

[0004] In summary, structural integrity management is shifting from periodic nondestructive testing to continuous structural health monitoring based on permanently installed sensor arrays. Unlike traditional periodic testing or online detectors, permanently installed ultrasonic arrays (including adhesive or clamped arrays) can exclude ultrasonic coupling interference, track and quantitatively evaluate the small development of defects in real time, thereby providing reliable data support for risk-based maintenance decisions and early warning.

[0005] However, sensor long-term service reliability, acoustic coupling stability and intelligent interpretation of multi-path signals are still key issues to be solved. Specifically, the inventors have found in actual use that the existing ultrasonic array sensors widely use negative square wave excitation method and cooperate with general ultrasonic array controllers for ultrasonic imaging monitoring, but this method has large signal noise, many imaging artifacts and long acquisition time, and cannot meet the requirements of acquisition efficiency and imaging quality. SUMMARY

[0006] Based on this, in view of the problems of large signal noise and many imaging artifacts in the existing acquisition mode, an ultrasonic phased patch sensor, a structural health monitoring system and method are provided.

[0007] The application adopts the following technical solutions:

[0008] In a first aspect, the application discloses an ultrasonic phased patch sensor, which comprises a flexible circuit board, a piezoelectric sensing array, a positive signal layer and a negative shielding layer.

[0009] The flexible circuit board is printed with N signal wires; one end of the flexible circuit board is provided with a through hole, and the other end is provided with a circuit connector for interaction.

[0010] The piezoelectric sensing array is arranged on the side of the flexible circuit board facing the object to be measured, and comprises N arrayed piezoelectric sensing units. Each piezoelectric sensing unit comprises one piezoelectric element, one element negative electrode and one element positive electrode. n In the first piezoelectric sensing unit: the first element positive electrode is covered on one side of the first piezoelectric element close to the flexible circuit board and is connected to the circuit connector through the first signal wire; and the first element negative electrode covers one side of the first piezoelectric element away from the flexible circuit board and is wound to the other side of the first piezoelectric element close to the flexible circuit board, and does not contact the first element positive electrode. n n n n n n n n ∈[1, N ]。

[0011] The positive signal layer comprises N positive signal elements; the first positive signal element is located between the first element positive electrode and the flexible circuit board and forms a stack. n n The negative shielding layer covers one side of the flexible circuit board away from the piezoelectric sensing array and extends from the through hole to one side of the flexible circuit board close to the piezoelectric sensing array and branches out

[0012] negative signal elements; the first negative signal element is located between the first element negative electrode and the flexible circuit board and forms a stack. N n n

[0013] The ultrasonic phased patch sensor realizes the method or process according to the embodiments of the present application.

[0014] ​​​​​​​​​​​In a second aspect, the application discloses a structural health monitoring system, comprising: a host computer, an ultrasonic array controller, and an ultrasonic phased patch sensor.

[0015] The host computer, the ultrasonic array controller, and the ultrasonic phased patch sensor are in communication connection. The ultrasonic array controller is designed with a multiplexing circuit and is used to control the ultrasonic phased patch sensor to collect ultrasonic array full-matrix data through a preset coding excitation mode and transmit echo data to the host computer; and the host computer is used to receive the echo data and process the echo data into an ultrasonic image.

[0016] Compared with the prior art, the application has the following beneficial effects:

[0017] 1. The application provides a flexible ultrasonic phased patch sensor, which sets positive and negative poles of a piezoelectric sensing unit on the same side of a flexible circuit board, forms a plurality of layers of circuits by passing through a through hole to extend to the other side of the flexible circuit board, and realizes separation from a positive pole signal layer, so that the cost is low, parasitic capacitance between generated signals and a to-be-measured object and electromagnetic interference between signal lines are effectively reduced, electronic noise of the signals is reduced, and the imaging signal-to-noise ratio is improved.

[0018] 2. The application provides a structural health monitoring system, which designs an ultrasonic array controller with a multiplexing circuit, effectively reduces the circuit volume, and leaves enough space for function expansion, so as to provide reasonable hardware support for ultrasonic array full-matrix data collection through a preset coding excitation mode, and improve the efficiency of full-matrix data collection while improving the imaging signal-to-noise ratio. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0020] Figure 1 A top view of the ultrasonic phased patch sensor provided in Embodiment 1 of the application;

[0021] Figure 2 A view after removing the piezoelectric sensing array; Figure 1 A view after removing the piezoelectric sensing array;

[0022] Figure 3 A bottom view of the ultrasonic phased patch sensor provided in Embodiment 1 of the application;

[0023] Figure 4This is a side view of the ultrasonic phased array patch sensor provided in Embodiment 1 of the present invention;

[0024] Figure 5 This is a simulation example of the piezoelectric sensing array provided in Embodiment 1 of the present invention;

[0025] Figure 6 This is a structural diagram of the structural health monitoring system provided in Embodiment 2 of the present invention;

[0026] Figure 7 This is a waveform diagram of the ultrasonic digital excitation pulse signal provided in Embodiment 2 of the present invention;

[0027] Figure 8 This is a comparison chart of experimental results provided in Embodiment 2 of the present invention;

[0028] The symbols in the attached diagram have the following meanings:

[0029] 1. Flexible circuit board; 2. Signal cable; 3. Circuit connector; 4. Piezoelectric sensing unit; 5. Negative shielding layer; 6. Through hole; 7. Positive signal element; 8. Negative signal element;

[0030] 401, piezoelectric element; 402, positive electrode of element; 403, negative electrode of element. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be noted that when a component is said to be "installed on" another component, it can be directly on the other component or it may be in a component that is centered on it. When a component is said to be "set on" another component, it can be directly set on the other component or it may also be in a component that is centered on it. When a component is said to be "fixed to" another component, it can be directly fixed to the other component or it may also be in a component that is centered on it.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0034] First, it should be noted that, as mentioned in the background section, existing acquisition methods suffer from problems such as high signal noise, numerous imaging noise points, and long acquisition times. Analysis revealed two main reasons for this:

[0035] 1. The existing ultrasonic array sensor structure design is unreasonable, and it is easily affected by parasitic capacitance and electromagnetic interference between signal lines during data acquisition.

[0036] 2. Existing general-purpose ultrasonic array controllers are based on a single-channel design and have a large circuit size. Due to the size of the components, it is difficult to expand the functionality of existing general-purpose ultrasonic array controllers. They can only be used with simple negative square wave excitation. As a result, multiple averaging is required to suppress noise when achieving full matrix acquisition, but the acquisition effect is still poor and the acquisition time is indirectly prolonged.

[0037] Based on this, the present invention first proposes a structurally optimized ultrasonic phased array patch sensor, then proposes an ultrasonic array controller in combination with the ultrasonic phased array patch sensor, and constructs a structural health monitoring system.

[0038] Example 1

[0039] See Figures 1-4 This is a multi-angle view of the ultrasonic phased array patch sensor provided in Embodiment 1. It is a flexible ultrasonic array patch sensor that can be adapted to flat or curved objects.

[0040] like Figures 1-4 As shown, the ultrasonic phased array patch sensor includes: a flexible circuit board, a piezoelectric sensing array, a positive signal layer, and a negative shielding layer.

[0041] First, a flexible printed circuit (FPC) is used as the circuit substrate. The flexible printed circuit board has printed circuitry... N Road signal cable ( N ≥1) – It serves as a signal transmission line. One end of the flexible circuit board has a through-hole, and the other end has a circuit connector for interaction – it connects with… N Connect the signal cable.

[0042] In this embodiment 1, to facilitate printing and assembly, it is recommended to connect the circuit connector with... N Connect the end of the signal cable. See below. Figure 3 ,by Figure 3 Taking the center direction as an example, the through-hole is located near the left end of the flexible circuit board, and the circuit connector is located near the right end of the flexible circuit board. It should be noted that the flexible circuit board can be made of any of the following materials: polyimide, polyester, or polytetrafluoroethylene, which can provide sufficient flexible support.

[0043] It should be noted that, N Theoretically, there is no upper limit; but considering that it will be used with the ultrasonic array controller later, and the ultrasonic array controller currently supports at most 128 channels, the upper limit of N is set to 128.

[0044] Next, looking at the piezoelectric sensing array, which is arranged on the side of the flexible circuit board facing the object to be measured, as the active end of the ultrasonic phased patch sensor. Referring to Figure 4 , the piezoelectric sensing array includes: an array of N piezoelectric sensing units. Each piezoelectric sensing unit includes: 1 piezoelectric element, 1 element negative electrode, 1 element positive electrode. Then, taking the first n piezoelectric sensing unit as an example: in the first n piezoelectric sensing unit, the first n element positive electrode covers one side of the first n piezoelectric element close to the flexible circuit board, and is connected to the circuit connector through the first n signal cable (in this embodiment 1, it is recommended to be connected to the head end of the first n signal cable); the first n element negative electrode covers the other side of the first n piezoelectric element away from the flexible circuit board, and is wound to the side (see Figure 4 , it is recommended to be wound from the side away from the circuit connector) of the first n piezoelectric element close to the flexible circuit board, and does not contact the first n element positive electrode; n ∈[1, N ].

[0045] As shown in Figure 1 , adjacent piezoelectric sensing units are not in contact; in addition, referring to Figure 4 , the element negative electrode and the element positive electrode are separated, but they are located on the same side of the flexible circuit board, which facilitates processing and assembly.

[0046] It should be noted that the material of the piezoelectric element is any one of the single-element system (such as barium titanate) piezoelectric ceramic, binary system (such as lead zirconate titanate) piezoelectric ceramic, ternary system (such as niobium-magnesium-zirconium-lead titanate, sodium-potassium-lithium niobate) piezoelectric ceramic. The material of the element negative electrode is any one of silver and gold. The material of the element positive electrode is any one of silver and gold. Among them, the element negative electrode and the element positive electrode are recommended to use the same material.

[0047] In addition, for the piezoelectric sensing array, the configuration parameters include: the total number of elements sn , element width sw , element spacing spThe optimal combination of these three parameters will change depending on the object under test. Therefore, considering the acquisition effect, the piezoelectric sensing array is the optimal parameter array determined by simulation optimization based on the object under test to reduce imaging artifacts.

[0048] Specifically, methods for determining the optimal parameter array through simulation optimization include:

[0049] S1. A two-dimensional sound wave propagation simulation model is constructed based on the spherical wave assumption of Huygens' principle and the Rayleigh-Sommerfeld integral formula—the formula is as follows:

[0050] ;

[0051] In the formula, ( x , z ) represents a pixel in the spatial domain; x express x Axial dimension; z express z Axial dimension; h ( x , z )express( x , z The wave field intensity (i.e., pressure or strain). h' ( s x , s z ) represents the excitation point in the spatial domain. s The acoustic excitation intensity (i.e., pressure, strain, or voltage); s x , s z ) represents the excitation point in the spatial domain. s of x Axis coordinates z Axis coordinates; r Indicates incentive points s To pixel ( x , z The distance; k Indicates wave number; λ Indicates wavelength.

[0052] S2, using the Full Matrix Capture (FMC) method, constructs an ultrasound full-focusing imaging model based on a two-dimensional sound wave propagation simulation model—its formula is as follows:

[0053] ;

[0054] In the formula, i (x , z ) represents the pixel amplitude of the analog imaging region; x , z ) represents the pixel amplitude of the analog imaging region; h ( t ) tn,rn represents the first tn ultrasound echo signal excited and received by the first rn array element according to the full-matrix acquisition rule h at the corresponding time domain t ; v l represents the longitudinal wave speed of the acoustic wave in the analog medium v l which can be replaced by other ultrasonic wave vibration modal wave speeds according to the imaging needs, such as the transverse wave speed v t , the surface wave speed v s , etc.); represents the tn axis coordinate of the first x array element; represents the tn axis coordinate of the first z array element; represents the rn axis coordinate of the first x array element; represents the rn axis coordinate of the first z array element.

[0055] S3, adjust the values of sn , sw , sp so that sn is as small as possible and i ( x , z ) is as large as possible.

[0056] For the convenience of understanding, this embodiment 1 gives a simulation example-configuration of three different configuration parameters in the 50mm thick carbon steel medium to simulate and compare the imaging performance of the 25mm deep, 0.1mm diameter measurement hole defect, and the results are shown in Figure 5 .

[0057] Among them, Figure 5 the (a) area shows the ultrasonic full-focus imaging result of 28 array elements, 1.0mm array element spacing, and 0.8mm array element width; Figure 5 the (b) area shows the ultrasonic full-focus imaging result of 22 array elements, 1.2mm array element spacing, and 1.0mm array element width;Figure 5 Region (c) shows the ultrasound full-focus imaging results with 14 array elements, an element spacing of 2.0 mm, and an element width of 1.8 mm. It can be seen that... Figure 5 The imaging effect in region (c) is the best (i.e., the imaging artifact effect is the smallest) and the total number of array elements is the smallest, indicating that its corresponding configuration parameters are the optimal parameters.

[0058] Continuing to examine the positive electrode signal layer, it includes: N The first positive signal element. n The positive signal element is located at the first n The positive electrode of each element is stacked between the positive electrode and the flexible circuit board. Generally, it is recommended that the positive signal layer be deposited on the flexible circuit board by electroplating or deposition, and it should be ensured that adjacent positive signal elements do not make contact. It should be noted that the material of the positive signal layer can be any of copper, silver, or gold.

[0059] Finally, let's look at the negative electrode shielding layer. It covers the side of the flexible circuit board away from the piezoelectric sensing array and extends from the through-hole to the side of the flexible circuit board closer to the piezoelectric sensing array, and then branches out... N The negative signal element. n The negative signal element is located at the first n Each array element's negative electrode is stacked between itself and the flexible circuit board. Similar to the positive signal layer, the negative electrode shielding layer (which also includes the negative signal elements) is recommended to be applied to the flexible circuit board by electroplating or deposition, ensuring that adjacent negative signal elements do not come into contact. It should be noted that the material of the negative electrode shielding layer (which also includes the negative signal elements) can be any of copper, silver, or gold.

[0060] Combination Figure 4 As can be seen, the negative electrode shielding layer forms a multi-layer circuit by passing through through-holes to extend to the other side of the flexible circuit board and is separated from the positive electrode signal layer. In this way, the negative electrode shielding layer can achieve grounded signal shielding, reduce electromagnetic interference of signal lines, reduce electronic noise of signals, and improve the signal-to-noise ratio of subsequent imaging.

[0061] In summary, it is recommended to use a coupling agent to enhance the connection between the piezoelectric sensing array and the object under test (DUT) to achieve stable acoustic contact and ensure efficient transmission of acoustic energy to the DUT. The ultrasonic phased array patch sensor supports full-matrix data acquisition—that is, selecting different piezoelectric array elements to emit plane waves with different incident angles towards the DUT under the action of an excitation signal. This achieves multi-angle acoustic field coverage of the DUT area with a small amount of excitation. When the sound waves propagate inside the DUT, they encounter discontinuous interfaces such as cracks, holes, or corrosion, resulting in reflections and characteristic echoes. Subsequent processing of the echoes from each array element enables focused imaging.

[0062] Example 2

[0063] Referring to Figure 6 Fig. 1 is a structural diagram of a structural health monitoring system provided in Embodiment 2, which serves as a complete monitoring system and supports high-fitting structural health detection of a to-be-detected object.

[0064] As Figure 6 shown, a structural health monitoring system comprises a host computer, an ultrasonic array controller, and an ultrasonic phased patch sensor disclosed in Embodiment 1. The host computer, the ultrasonic array controller, and the ultrasonic phased patch sensor are in communication connection.

[0065] 1. For the ultrasonic phased patch sensor, refer to Embodiment 1. It is necessary to supplement here that the circuit connection head of the ultrasonic phased patch sensor is generally connected with the ultrasonic array controller through a multi-channel conversion connector.

[0066] 2. For the ultrasonic array controller, it is designed in combination with the ultrasonic phased patch sensor, that is, a multiplexing circuit is adopted. In this way, the circuit volume can be effectively reduced, and sufficient space is left for function expansion, that is, coded excitation is introduced. In general, the ultrasonic array controller is used to control the ultrasonic phased patch sensor to perform ultrasonic array full-matrix data acquisition through a preset coded excitation mode, and transmit the echo data to the host computer.

[0067] Specifically, the ultrasonic array controller comprises a single-channel ultrasonic wave controller, a transmitting-end multiplexing module, a preamplification module, an overvoltage protection module, and a receiving-end multiplexing module.

[0068] As Figure 6 shown, the communication end of the single-channel ultrasonic wave controller is in communication connection with the host computer (which can be wired communication or wireless communication), the signal transmitting end is connected with the transmitting-end multiplexing module, and the signal receiving end is sequentially connected with the preamplification module, the overvoltage protection module, and the receiving-end multiplexing module. The transmitting-end multiplexing module and the receiving-end multiplexing module each have N one channel signal output end; and the transmitting-end multiplexing module and the receiving-end multiplexing module are connected with the ultrasonic phased patch sensor in a parallel manner.

[0069] The following introduces each module:

[0070] ① The single-channel ultrasonic controller is used to: generate ultrasonic digital excitation pulse signals according to a preset coded excitation method, and convert them into analog excitation pulse signals to act on the transmitter multiplexing module; receive analog echo amplification signals from the preamplifier module, and convert them into digital echo amplification signals as echo data. In this embodiment 1, the single-channel ultrasonic controller can be TiePie's HS5, CodeAc's CA1, or Lecoeur Electronique's US-SPI. Of course, other models with the above functions can also be used instead.

[0071] It should be noted that the preset coding excitation method is frequency- or phase-modulated coding excitation, such as Chirp coding excitation, Barker coding excitation, and Golay coding excitation. In this embodiment 1, Chirp coding excitation is recommended, and its processing formula is as follows:

[0072] ;

[0073] In the formula, f s Indicates the start frequency of the Chirp-coded excitation signal; B This represents the bandwidth of the Chirp-coded excitation signal; w ( t ) indicates that the function is passed to the rectangle; λ Indicates wavelength; h' ( t ) represents the Chirp-coded excitation signal in the time domain.

[0074] The above-mentioned coding excitation method can achieve higher energy accumulation while keeping the transmission power constant, effectively improving the signal-to-noise ratio of the echo, thereby improving the detectability of weak defect signals during the propagation of ultrasonic body waves and significantly improving the ability to identify early minor damage to structures. This can also reduce the average number of times the same signal is acquired, thereby improving the acquisition efficiency of ultrasonic array data, which is particularly suitable for the application scenarios of this invention.

[0075] ② The transmitter multiplexing module is used to control the ultrasonic phased array patch sensor. N Each piezoelectric sensing unit switches excitation array elements according to a full matrix acquisition method.

[0076] The receiver multiplexing module is used to control the ultrasonic phased array patch sensor. N Each piezoelectric sensing unit switches the receiving array element according to the full matrix acquisition method.

[0077] Specifically, the signal input terminal of the transmitter multiplexing module is connected to the signal transmitter terminal of the single-channel ultrasonic controller. NThe channel signal output end is left for connecting with the ultrasonic phased patch sensor N The signal input end of the receiving end multiplexing module is connected with the over-voltage protection module, N The channel signal output end is left for connecting with the ultrasonic phased patch sensor N The array element receiving interface is connected with the over-voltage protection module. n The array element transmitting interface, the piezoelectric sensing unit and the array element receiving interface are connected in sequence. n n In this way, the array element transmitting interface, the piezoelectric sensing unit and the array element receiving interface form a series connection; but from the perspective of the angle,

[0078] In this way, the array element transmitting interface, the piezoelectric sensing unit and the array element receiving interface form a series connection; but from the perspective of the angle, n n In this way, the array element transmitting interface, the piezoelectric sensing unit and the array element receiving interface form a series connection; but from the perspective of the angle, n N In this way, the array element transmitting interface, the piezoelectric sensing unit and the array element receiving interface form a series connection; but from the perspective of the angle, N In this way, the array element transmitting interface, the piezoelectric sensing unit and the array element receiving interface form a series connection; but from the perspective of the angle,

[0079] In the embodiment 1, the transmitting end multiplexing module and the receiving end multiplexing module can adopt the same model, for example, the HV2801K6-G of Microchip. Of course, other models with the above functions can also be replaced.

[0080] ③ The over-voltage protection module is used to prevent the analog excitation pulse signal from directly entering the signal receiving end of the single-channel ultrasonic controller to protect the related components.

[0081] In the embodiment 1, the over-voltage protection module can adopt the TX810 of Texas Instruments. Of course, other models with the above functions can also be replaced.

[0082] ④ The preamplification module is used to reduce noise and amplify the ultrasonic analog echo signal from the receiving end multiplexing module to obtain an analog echo amplified signal, which is then transmitted to the upper computer.

[0083] In the embodiment 1, the preamplification module can adopt the LT1222 of Analog Devices. Of course, other models with the above functions can also be replaced.

[0084] 3, The upper computer is used to receive echo data and process it into an ultrasonic image.

[0085] Specifically, the upper computer focuses the echo data after filtering and decoding processing according to the full-focus ultrasonic imaging method, that is, outputs an ultrasonic image.

[0086] ​​​To illustrate the effectiveness of the aforementioned structural health monitoring system, Example 2 provides an experimental comparison—the existing data acquisition method and the aforementioned structural health monitoring system were used to detect the test object sequentially. The results are shown below. Figure 7 : Figure 7 The middle (a) region shows ultrasound images obtained using existing acquisition methods; Figure 7 The middle (b) region shows the ultrasound images obtained by the above-mentioned structural health monitoring system.

[0087] The test object is a carbon steel block with a thickness of 50 mm. A 2 mm diameter side through hole defect is pre-placed at a depth of 25 mm inside the block to simulate the porosity damage present in the structure.

[0088] The existing acquisition method uses negative square wave excitation, applying a square wave excitation signal with a negative excitation voltage. The structural health monitoring system uses Chirp-coded excitation, applying a Chirp-coded excitation signal with a center frequency of 5MHz and a bandwidth of 2MHz. Figure 8 As shown: Figure 8 The middle region (a) shows the waveform of the Chirp-coded excitation signal in the time domain; Figure 8 The middle (b) region shows the waveform of the Chirp-coded excitation signal in the frequency domain.

[0089] Depend on Figure 7 It can be seen that, compared with existing acquisition methods, the ultrasonic images obtained by the structural health monitoring system have better noise suppression near defects, significantly reduced artifacts, and reduced the average amplitude of imaging noise by 4dB.

[0090] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An ultrasonic phased array patch sensor, characterized in that, It includes: Flexible circuit boards, which are printed with N Road signal cable; One end of the flexible circuit board has a through hole, and the other end has a circuit connector for interaction. A piezoelectric sensing array, disposed on the side of a flexible circuit board facing the object under test, includes: an array distribution... N Each piezoelectric sensing unit comprises: one piezoelectric element, one negative electrode of the element, and one positive electrode of the element; in the first... n In the piezoelectric sensing unit: the first n The positive electrode of the array element is covered in the first n A piezoelectric element is located near one side of the flexible circuit board, and through the first n The signal cable connector is connected to the circuit connector; n The negative electrode of the array element is covered with the first n Each piezoelectric element is located away from the side of the flexible circuit board and wraps around to the first side. n The piezoelectric element is located on the side of the flexible circuit board and is adjacent to the first piezoelectric element. n The positive terminals of the individual elements do not touch. n ∈[1, N ]; The positive signal layer includes: N The positive signal element; the first n The positive signal element is located at the first n The positive electrode of each element and the flexible circuit board are stacked together; and A negative electrode shielding layer covers the side of the flexible circuit board away from the piezoelectric sensing array and extends from the via to the side of the flexible circuit board closer to the piezoelectric sensing array, and is separated into... N The negative polarity signal element; the first n The negative signal element is located at the first n The negative electrode of each element and the flexible circuit board are stacked together.

2. The ultrasonic phased array patch sensor according to claim 1, characterized in that, The flexible circuit board is made of any one of polyimide, polyester, or polytetrafluoroethylene. Or / and, the material of the positive electrode signal layer is any one of copper, silver, and gold; Or / and, the material of the negative electrode shielding layer is any one of copper, silver, and gold; Or / and, the material of the piezoelectric array element is any one of the following: single-element piezoelectric ceramic, binary piezoelectric ceramic, and ternary piezoelectric ceramic; Or / and, the material of the negative electrode of the array element is either silver or gold; Or / and, the material of the positive electrode of the array element is either silver or gold.

3. The ultrasonic phased array patch sensor according to claim 1, characterized in that, The piezoelectric sensing array is an optimal parameter array determined by simulation optimization based on the object under test to reduce imaging artifact effects.

4. A structural health monitoring system, characterized in that, It includes: host computer An ultrasonic array controller and an ultrasonic phased array patch sensor as described in any one of claims 1-3; The host computer, ultrasonic array controller, and ultrasonic phased array patch sensor are connected in communication. The ultrasonic array controller adopts a multiplexed circuit design to control the ultrasonic phased array patch sensor to perform full matrix data acquisition of the ultrasonic array through preset coded excitation and transmit the echo data to the host computer. The host computer is used to receive the echo data and process it into an ultrasonic image.

5. The structural health monitoring system according to claim 4, characterized in that, The ultrasonic array controller includes: a single-channel ultrasonic controller, a transmitter multiplexing module, a preamplifier module, an overcurrent protection module, and a receiver multiplexing module; The single-channel ultrasonic controller's communication terminal is connected to a host computer. The signal transmitter is connected to a transmitter multiplexing module, and the signal receiver is sequentially connected to a preamplifier module, an overcurrent protection module, and a receiver multiplexing module. Both the transmitter and receiver multiplexing modules have... N Each channel has a signal output terminal; the transmitter multiplexer module and the receiver multiplexer module are connected in parallel to the ultrasonic phased array patch sensor; The single-channel ultrasonic controller is used to: generate ultrasonic digital excitation pulse signals according to a preset coded excitation method and convert them into analog excitation pulse signals to act on the transmitter multiplexing module; receive analog echo amplification signals from the preamplifier module and convert them into digital echo amplification signals as echo data; The transmitter multiplexing module is used to control the ultrasonic phased array patch sensor. N Each piezoelectric sensing unit switches excitation array elements according to a full matrix acquisition method; The receiver multiplexing module is used to control the ultrasonic phased array patch sensor. N Each piezoelectric sensing unit switches receiving array elements according to a full matrix acquisition method; The overcurrent protection module is used to prevent analog excitation pulse signals from directly entering the signal receiving end of the single-channel ultrasonic controller in order to protect related components. The preamplifier module is used to: reduce noise and amplify the ultrasonic analog echo signal from the multiplexing module at the receiving end to obtain the analog echo amplified signal, and then transmit it to the host computer.

6. The structural health monitoring system according to claim 5, characterized in that, The communication terminal of the single-channel ultrasonic controller communicates with the host computer via wired or wireless communication.

7. The structural health monitoring system according to claim 5, characterized in that, The signal input terminal of the transmitter multiplexing module is connected to the signal transmitter terminal of the single-channel ultrasonic controller. N The channel signal output terminal is reserved for connection with an ultrasonic phased array patch sensor. N Each array element's transmission interface; The signal input terminal of the receiver multiplexing module is connected to the overcurrent protection module. N The channel signal output terminal is reserved for connection with an ultrasonic phased array patch sensor. N Individual array element receiving interface; Among them, the n Each element's transmission interface, the first n The first piezoelectric induction unit, the first n The receiver interfaces of each array element are connected sequentially.

8. The structural health monitoring system according to claim 7, characterized in that, The circuit connector of the ultrasonic phased array patch sensor is connected to the ultrasonic array controller via a multi-channel adapter.

9. The structural health monitoring system according to claim 5, characterized in that, The preset coding excitation method is frequency- or phase-modulated coding excitation.

10. The structural health monitoring system according to claim 9, characterized in that, The preset coding incentive methods are: Chirp coding incentive, Barker coding incentive, or Golay coding incentive.

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