A method and device for decomposing Lamb wave response packets under multi-mode conditions

Abstract

The present invention discloses a method and device for decomposing a wave packet of a Lamb wave mode under multi-mode conditions. The method comprises: obtaining a Lamb wave response signal; decomposing the wave packet of the response signal using a pre-constructed reference signal to obtain a residual signal and a decomposed reference wave packet, repeating the above process until the absolute maximum value of the residual signal is less than a set threshold to complete the decomposition of the response signal; and reconstructing a new response signal using a narrow pulse based on the decomposed reference wave packet. The multi-modal response signal can be processed, decomposed into multiple wave packets and reconstructed, solving the problem of wave packet deformation or even aliasing due to frequency dispersion, thereby improving the accuracy and stability of damage imaging monitoring.

Description

Technical Field

[0001] The invention belongs to the technical field of Lamb wave response signal processing, and relates to a method and device for decomposing a Lamb wave response packet under multi-mode conditions, which is a method for decomposing a response signal having multiple modes. Background Art

[0002] Variable thickness materials are often used in aerospace, wind power generation and other fields. In the field of aerospace, aircraft are often affected by airflow during their flight in the atmosphere, and the most important part of the aircraft is the wing, which is a typical variable thickness structure; in the field of aviation, spacecraft may be hit by space debris when sailing in the universe. If the hull material is not monitored and repaired in time, the spacecraft may disintegrate in outer space, seriously threatening the life safety of astronauts; in the field of wind power generation, wind power generation devices may be placed in some harsh areas, and they are often impacted by some unidentified objects during operation. If the impact point is not located and the health status of the material is not monitored, the device is likely to have an accident. In summary, effective and timely monitoring of the health status of these variable thickness materials is an indispensable part. Effective and timely health monitoring of them helps reduce the probability of accidents and save costs, and can also promote the development of aerospace and wind power generation in turn.

[0003] At present, there are many schemes that can be used in non-destructive testing of structural objects. For example, the main methods are: infrared detection, ultrasonic detection, X-ray detection, magnetic particle detection and eddy current detection, etc. However, these detection schemes have their limitations, mainly reflected in the fact that the detection results may be affected by environmental factors, or the complexity of the structure makes the detection conditions complicated, which ultimately makes real-time online monitoring difficult. For example, in infrared detection technology, any object will actively radiate infrared rays. Its detection principle is to use this point to evaluate the health of the structure by measuring the different thermal conductivity parameters of the structure before and after damage. However, its detection results are only more accurate in the ideal environment of a laboratory with strictly controlled conditions. These structures are often used in complex outdoor environments, and the infrared rays radiated by the structure are also affected, so its detection results are likely to be very unreliable; while X-ray detection technology is subject to the high cost and large volume of the detection instrument, and the real-time detection is not strong, so it is difficult to achieve online monitoring. After comparison, ultrasonic detection is a cost-effective and commonly used solution. Excitation points and response receiving points are installed on the structure. The excitation points are used to excite ultrasonic signals, and the receiving points receive the response signals. The signal spectrum is analyzed to determine whether there is damage on the structure, and then its health status is evaluated. However, the propagation of Lamb waves (a special type of ultrasonic wave, often used as an excitation signal for structural health monitoring) in the structure is a complex process, especially in materials with variable thickness, the propagation process of Lamb waves often suffers from severe frequency dispersion.

[0004] There are multiple modes in the process of Lamb wave propagation. Summary of the invention

[0005] If a narrowband signal in the time domain, i.e. a broadband signal in the frequency domain, is used, it will inevitably cause complex signal dispersion and mode aliasing, making it impossible to determine the signal mode and difficult to extract features from the most important signal. On the contrary, if a broadband signal in the time domain, i.e. a narrowband signal in the frequency domain, is used, although the signal mode can be kept in a relatively single state and will not cause serious dispersion, its response signal is very prone to wave packet aliasing, which has a serious impact on correct monitoring.

[0006] Therefore, in order to overcome the wave packet aliasing of low-frequency signals and prevent the occurrence of multimodal signals with a wider frequency domain during propagation, this paper proposes a method to decompose the response signal from an energy perspective and then use a narrower wave packet to reconstruct the original response signal, thereby solving the problem of wave packet aliasing and improving the accuracy and stability of damage imaging monitoring.

[0007] The innovation of the present invention is that it can process multi-modal response signals, decompose them into multiple wave packets and reconstruct them, thus solving the problem of wave packet deformation or even aliasing caused by frequency dispersion.

[0008] In order to achieve the above objectives, the technical solutions adopted are:

[0009] In a first aspect, a method for decomposing a Lamb wave response wave packet is provided, comprising:

[0010] Get Lamb wave response signal;

[0011] Decompose the wave packet of the response signal using the pre-constructed reference signal:

[0012] Determine the peak position t of the maximum wave packet of the response signal i and amplitude a i Based on a pre-constructed reference signal, wherein the reference signal has an amplitude of a i The excitation signal is set to the same peak moment of the reference signal as the peak moment of the maximum wave packet of the response signal, and the reference signal amplitude is adjusted to be the same as the peak value of the maximum wave packet. The adjusted reference signal is subtracted from the response signal to achieve the decomposition of the maximum wave packet, and the residual signal and the decomposed reference wave packet (t di ,a i ), t di is the time axis position of the reference wave packet decomposed for the i-th time; repeat the above process until the maximum absolute value of the residual signal is less than the set threshold to complete the decomposition of the response signal;

[0013] According to the decomposed reference wave packet (t di ,a i ), and use the narrow pulse to reconstruct the new response signal. The reconstructed response signal is Σa i ×v l (tt di ), where v l (tt di ) represents the narrow pulse constructed at the original time location of the reference wave packet decomposed for the i-th time.

[0014] In some embodiments, the excitation signal is expressed as:

[0015]

[0016] Where: Heaviside is a step signal; t is a time variable; N is the number of cycles, f c is the center frequency of the signal, and A is the signal amplitude.

[0017] In some embodiments, decomposing the wave packet of the response signal using the pre-constructed reference signal includes:

[0018] Take the absolute value of the response signal v(t) to obtain |v(t)|;

[0019] Find the maximum value point of the absolute value signal and determine the coordinates of the maximum value point (t i ,y i ), where t i The horizontal axis is time, y i is the vertical axis amplitude, y i =a i , i is a positive integer; i is the number of decompositions;

[0020] Based on the excitation signal v a (t) Construct the reference signal of the decomposed response signal, the unit excitation signal v a (t) / A, where A is the amplitude of the excitation signal; the unit excitation signal is time-shifted to t on the time axis. i The amplitude adjustment is performed at the same time, and the amplitude adjustment coefficient is a i , the reference signal expression is: v ai (t) = a i ×v a (tt i ) / A, i is a positive integer;

[0021] Reference signal position fine-tuning Set the reference signal v ai (t) time shift 1 / (4f c ), so the total time shift is t di =t i +1 / (4f c )-N / (2f c ), the expression of the reference signal after position fine-tuning is adjusted to v ai (t) = a i ×v a (tt di ) / A, i is a positive integer;

[0022] When the coordinate of the absolute maximum value is above the zero axis before taking the absolute value, the phase of the reference signal and the local response signal are aligned, and the residual response v is obtained by difference. i+1 (t) = v i (t)-v ai (t), complete a signal decomposition iteration; when the coordinate of the absolute maximum value is below the zero axis before taking the absolute value, the phase of the reference signal and the local response signal is completely opposite, then for v ai (t) is negative and then subtracted to obtain the residual response v i+1 (t) = v i (t)+v ai (t), one signal decomposition iteration is completed.

[0023] The method for decomposing the Lamb wave response wave packet is as follows: the first signal decomposition is for the initial response signal, and the signal decomposition after the first decomposition is for the residual response v after the previous decomposition. i+1 (t).

[0024] In some embodiments, the threshold is set to a1 / 4, where a1 is the maximum amplitude of the absolute value of the initial response signal.

[0025] In some embodiments, the narrow pulse is constructed using a unit Gaussian function, and the pulse width of the narrow pulse is ≤ 1 / 2 of the pulse width of the excitation signal.

[0026] In some embodiments, a method for simulating a Lamb wave response signal includes:

[0027] For a thin plate structure object, a coordinate system is established with the center of the plate as the origin, and at least two piezoelectric transducers are attached to the thin plate structure as actuators or sensors, and the spacing between any adjacent piezoelectric transducers is greater than the length of a single pulse of the excitation signal;

[0028] Select one of the piezoelectric transducers as the exciter and the other piezoelectric transducers as the response sensor; load the narrowband excitation signal v on the exciter a (t), and collect the response signal on the sensor.

[0029] In some embodiments, the number of cycles N of the excitation signal is 5; the center frequency f c Take 100KHz and amplitude A as 5.

[0030] In a second aspect, a device for decomposing a Lamb wave response wave packet is provided, comprising a processor and a storage medium;

[0031] The storage medium is used to store instructions;

[0032] The processor is configured to operate according to the instructions to execute the steps according to the method.

[0033] According to a third aspect, a storage medium is provided, on which a computer program is stored, and the computer program implements the steps of the method when executed by a processor.

[0034] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects: a method and device for decomposing Lamb wave response packets under multi-mode conditions provided by the present invention can process multi-modal response signals, decompose them into multiple wave packets and reconstruct them, thereby solving the problem of wave packet deformation or even aliasing of signals due to frequency dispersion, thereby improving the accuracy and stability of damage imaging monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is the arrangement of the excitation points and receiving points of the present invention.

[0036] Figure 2 It is a time domain diagram of the excitation signal of the present invention.

[0037] Figure 3 It is to take the absolute value of the response signal.

[0038] Figure 4 The operation is to find the maximum value point.

[0039] Figure 5 is the constructed decomposition sub-signal.

[0040] Figure 6 Demonstrated is the alignment of the phase of the sub-signal with the phase of the local response signal.

[0041] Figure 7 It is shown that the phase of the sub-signal is opposite to the phase of the local response signal.

[0042] Figure 8 It is demonstrated that the constructed sub-signal is negated and the phase is aligned with the local response signal.

[0043] Fig. 9 is the remaining signal after one decomposition.

[0044] Fig.10 Construct a new wave packet signal (contour) at the location of the decomposed signal.

[0045] Fig.11 In order to reconstruct the constructed signal wave packet, a narrower signal wave packet is used for reconstruction.

[0046] Fig.12 is the response signal collected during the test.

[0047] Fig.13 is the contour diagram of the response signal.

[0048] Fig.14 This is the distribution diagram of the decomposed wave packet on the time axis.

[0049] Fig.15 Reconstruct the signal wave packet.

[0050] Fig.16 Sum the reconstructed wave packets. Specific implementation methods

[0051] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be interpreted as limiting the present invention.

[0052] In the description of the present invention, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0053] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0054] A method for decomposing a Lamb wave response wave packet, comprising:

[0055] Get Lamb wave response signal;

[0056] Decompose the wave packet of the response signal using the pre-constructed reference signal:

[0057] Determine the peak position t of the maximum wave packet of the response signal i and amplitude a i Based on a pre-constructed reference signal, wherein the reference signal has an amplitude of a i The excitation signal is set to the same peak moment of the reference signal as the peak moment of the maximum wave packet of the response signal, and the reference signal amplitude is adjusted to be the same as the peak value of the maximum wave packet. The adjusted reference signal is subtracted from the response signal to achieve the decomposition of the maximum wave packet, and the residual signal and the decomposed reference wave packet (t di ,a i ), t di is the time axis position of the reference wave packet decomposed for the i-th time; repeat the above process until the maximum absolute value of the residual signal is less than the set threshold to complete the decomposition of the response signal;

[0058] According to the decomposed reference wave packet (t di ,a i ), using narrow pulse v l (t) Reconstruct a new response signal. The reconstructed response signal is Σa i ×v li (tt di ), where v l (tt di) represents the narrow pulse constructed at the original time location of the reference wave packet decomposed for the i-th time.

[0059] In some embodiments, a method for decomposing a Lamb wave response wave packet under multimode conditions comprises the following steps:

[0060] Step 1: For thin plate structure objects, in this experiment, a thin aluminum plate is selected as the research object, and the size of the aluminum plate is 1000mm×1000mm×3mm. Take the center of the plate as the origin, establish a coordinate system, and paste piezoelectric transducers on the structure as exciters and sensors. The distance between the two is greater than the length of a single pulse of the excitation signal. The coordinates of transducer 1 are (0,250), the coordinates of transducer 2 are (0,-250), the coordinates of transducer 3 are (-250,0), and the coordinates of transducer 4 are (250,0). Figure 1 .

[0061] Step 2: Select one of the piezoelectric transducers as the excitation point and the other piezoelectric transducers as the response sensors. Load the narrowband excitation signal v on the exciter. a (t), and collect the response signal on the sensor. The excitation signal expression is as follows, and the signal waveform is as follows Figure 2 .

[0062]

[0063] Where: Heaviside is a step signal; t is a time variable;

[0064] N is the number of cycles, and in this embodiment, N is 5.

[0065] f c is the center frequency of the signal. In this embodiment, the center frequency is 100 KHz.

[0066] A is the signal amplitude, which is 5 in this embodiment.

[0067] Step 3: Response signal decomposition. Construct a reference signal. The initial construction method of the reference signal is an excitation signal with an amplitude of 1. Calculate the peak position t of the maximum wave packet of the response signal to be decomposed i and amplitude a i , shift the reference signal in time so that its peak moment is the same as the peak moment of the maximum wave packet, and adjust the reference signal amplitude to be the same as the peak value of the maximum wave packet, and make a difference between the adjusted reference signal and the response signal to achieve the decomposition of the maximum wave packet. Repeat the above process until the decomposition of the response signal is completed.

[0068] Step 4: According to the decomposed reference wave packet (t di ,a i ), using narrow pulse v l(t) Reconstruct the original response signal, and the reconstructed response is Σa i ×v l (tt di ), where v l (tt di ) represents the narrow pulse constructed at the original time of the reference wave packet decomposed for the ith time; t di =t i +1 / (4f c )-N / (2f c ), t di The calculation of is introduced in the specific process of step 3.

[0069] As a preferred solution of the present invention, the specific process of step 3 is:

[0070] Step 31: Collect the response signal v(t) on the sensor and take the absolute value |v(t)|, such as Figure 3 .

[0071] Step 32: Figure 4 , find the maximum point of the absolute value signal and calculate its coordinates (t i ,y i ), where a i =y i , i is a positive integer; i is the number of decompositions; y i is the maximum amplitude of the absolute value of the signal.

[0072] Step 33: Construct the reference signal of the decomposed response signal. First, construct the unit excitation signal, whose expression is v a (t) / A; shift the unit excitation signal to t on the time axis i The amplitude adjustment is performed at the same time, and the amplitude adjustment coefficient is a i , the reference signal is constructed, and its expression is: ai (t) = a i ×v a (tt i ) / A, i is a positive integer.

[0073] Step 34: Figure 5 If the time-shifted reference signal does not completely coincide with the local response signal, the reference signal position is fine-tuned. ai (t) time shift 1 / (4f c ). Therefore, the total time shift is t di =t i +1 / (4f c )-N / (2f c ). The expression of the reference signal is adjusted to v ai (t) = ai ×v a (tt di ) / A, i is a positive integer.

[0074] Step 35: Figure 6 , when the coordinate of the absolute maximum value is above the zero axis before taking the absolute value, the phase of the reference signal and the local response signal are aligned, and the difference is made at this time, that is, v i (t)-v ai (t), and obtain the residual response v i+1 (t), the first signal decomposition iteration is completed; Figure 7 , when the coordinate of the absolute maximum value is below the zero axis before taking the absolute value, the phases of the reference signal and the local response signal are completely opposite, then for v ai (t) Take the negative and make the difference, such as Figure 8 , the above process can also be expressed by summation, that is, v i (t)+v ai (t), and the residual response v is obtained i+1 (t), completing one signal decomposition iteration. The residual response is as follows Fig. 9 .

[0075] Step 36: Fig.10 and Fig.11 , at the original time point of the decomposition, a new narrower wave packet is used for reconstruction. One signal decomposition iteration is completed.

[0076] Step 37: Repeat the above steps until the absolute maximum value of the residual signal is less than a threshold. In this experiment, the threshold is a1 / 4.

[0077] As a preferred solution of the present invention, the narrow pulse v in step 4 l (t) is constructed using a unit Gaussian function, and its pulse width is ≤ 1 / 2 of the excitation signal pulse width. In this experiment, the pulse width of the constructed Gaussian pulse is one fifth of the original excitation signal pulse width.

[0078] Next, an example of signal processing is used to illustrate the advantages of the present invention. Fig.12 is the response signal collected during the test, such as Fig.13 is the contour diagram of the response signal, such as Fig.14 This is the distribution diagram of the decomposed wave packet on the time axis, such as Fig.15 Reconstruct the signal wave packet, such as Fig.16 Sum the reconstructed wave packet. As shown in the figure, the original signal and the wave packet are seriously aliased. After the signal decomposition iteration, the reconstructed wave packet has no aliasing problem.

[0079] Example 2

[0080] In a second aspect, the present embodiment provides a device for decomposing a Lamb wave response wave packet, including a processor and a storage medium;

[0081] The storage medium is used to store instructions;

[0082] The processor is used to operate according to the instructions to execute the steps of the method according to embodiment 1.

[0083] Example 3

[0084] In a third aspect, this embodiment provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in Example 1 are implemented.

[0085] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0086] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0087] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0088] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0089] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for decomposing a Lamb wave response packet, characterized in that: include: Get Lamb wave response signal; Decompose the wave packet of the response signal using the pre-constructed reference signal: Determine the peak position t of the maximum wave packet of the response signal i and amplitude a i Based on a pre-constructed reference signal, wherein the reference signal has an amplitude of a i The excitation signal is set to the same peak moment of the reference signal as the peak moment of the maximum wave packet of the response signal, and the reference signal amplitude is adjusted to be the same as the peak value of the maximum wave packet. The adjusted reference signal is subtracted from the response signal to achieve the decomposition of the maximum wave packet, and the residual signal and the decomposed reference wave packet (t di ,a i ), t di is the time axis position of the reference wave packet decomposed for the ith time; repeat the above process until the maximum absolute value of the residual signal is less than the set threshold to complete the decomposition of the response signal; According to the decomposed reference wave packet (t di ,a i ), and use the narrow pulse to reconstruct the new response signal. The reconstructed response signal is Σa i ×v l (tt di ), where v l (tt di ) represents the narrow pulse constructed at the original time location of the reference wave packet decomposed for the i-th time.

2. The method for decomposing Lamb wave response packets according to claim 1, characterized in that: The excitation signal is expressed as: Where: Heaviside is a step signal; t is a time variable; N is the number of cycles, f c is the center frequency of the signal, and A is the signal amplitude.

3. The method for decomposing Lamb wave response packets according to claim 1, characterized in that: The wave packet of the response signal is decomposed using the pre-constructed reference signal, including: Take the absolute value of the response signal v(t) to obtain |v(t)|; Find the maximum value point of the absolute value signal and determine the coordinates of the maximum value point (t i ,y i ), where t i The horizontal axis is time, y i is the vertical axis amplitude, y i =a i , i is a positive integer; i is the number of decompositions; Based on the excitation signal v a (t) Construct the reference signal of the decomposed response signal, the unit excitation signal v a (t) / A, where A is the amplitude of the excitation signal; the unit excitation signal is time-shifted to t on the time axis. i The amplitude adjustment is performed at the same time, and the amplitude adjustment coefficient is a i , the reference signal expression is: v ai (t) = a i ×v a (tt i ) / A, i is a positive integer; Reference signal position fine-tuning sets the reference signal v ai (t) time shift 1 / (4f c ), so the total time shift is t di =t i +1 / (4f c )-N / (2f c ), the expression of the reference signal after position fine-tuning is adjusted to v ai (t) = a i ×v a (tt di ) / A, i is a positive integer; When the coordinate of the absolute maximum value is above the zero axis before taking the absolute value, the phase of the reference signal and the local response signal are aligned, and the residual response v is obtained by difference. i+1 (t) = v i (t)-v ai (t), complete a signal decomposition iteration; when the coordinate of the absolute maximum value is below the zero axis before taking the absolute value, the phase of the reference signal and the local response signal is completely opposite, then for v ai (t) is negative and then subtracted to obtain the residual response v i+1 (t) = v i (t)+v ai (t), one signal decomposition iteration is completed.

4. The method for decomposing a Lamb wave response packet according to claim 3, characterized in that: The first signal decomposition is the initial response signal, and the signal decomposition after the first one is the residual response v after the previous decomposition. i+1 (t).

5. The method for decomposing a Lamb wave response packet according to claim 1, characterized in that: The threshold is set to a1 / 4, where a1 is the maximum amplitude of the absolute value of the initial response signal.

6. The method for decomposing a Lamb wave response packet according to claim 1, characterized in that: The narrow pulse v l (t) is constructed using a unit Gaussian function, and a narrow pulse v l The pulse width of (t) is ≤1 / 2 of the excitation signal pulse width.

7. The method for decomposing Lamb wave response packets according to any one of claims 1 to 6, characterized in that: The simulation method of Lamb wave response signal includes: For a thin plate structure object, a coordinate system is established with the center of the plate as the origin, and at least two piezoelectric transducers are attached to the thin plate structure as actuators or sensors, and the spacing between any adjacent piezoelectric transducers is greater than the length of a single pulse of the excitation signal; Select one of the piezoelectric transducers as the exciter and the other piezoelectric transducers as the response sensor; load the narrowband excitation signal v on the exciter a (t), and collect the response signal on the sensor.

8. The method for decomposing Lamb wave response packets according to claim 2, characterized in that: The number of cycles N of the excitation signal is 5; the center frequency f c Take 100KHz and amplitude A as 5.

9. A device for decomposing Lamb wave response packets, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 8.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

Images