CN114112921B - Damage detection method, system, medium and equipment based on litz transformation - Google Patents
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Abstract
Compared with the prior art, the damage detection method based on the litz transformation provided by the invention utilizes rich information contained in a guided wave place represented by an analysis signal to reflect damage information. The resolved signals derived from the litz transformation are used to obtain the spatial orientation, phase and amplitude of the reconstructed guided wave field. And spatially deriving the phase from the two coordinates to obtain a spatial wavenumber vector. The magnitude of the spatial wave number vector obtained by the litz transformation represents the spatial wave number value pointing in the propagation direction at each point of the control. The method can be used for relatively complex geometric structures by analyzing the phase information of the signal through the wave field, and evaluating the morphology and the position of the damage by combining the advantages of an algorithm and Lamb waves so as to obtain accurate damage depth information.
Description
Technical Field
The invention relates to the technical field of structure detection, in particular to a damage detection method based on litz transformation.
Background
Corrosion is a common damage in civilian petrochemical, nuclear, and aerospace structures, the presence of which can affect the integrity and safety of the structure and can lead to catastrophic failure. In the maintenance of aircraft, the corrosion damage accumulated by the aircraft during its service life is also a potential threat to flight safety, and the corrosion damage occurring to the fuselage has always been a major concern and requires more frequent inspection and maintenance. Thus, for example, it is of great importance to identify corrosion-type damage occurring in aircraft structures.
In conventional non-destructive inspection methods, ultrasonic inspection is often used to detect corrosion damage that may occur in aircraft, but the couplant used in conventional ultrasonic inspection may have an effect on the inspected material. The laser ultrasonic detection technology is used as an emerging nondestructive detection technology, and the principle is that ultrasonic waves are excited and received by utilizing laser, so that damage in materials and structures is detected, and a couplant is not needed in the detection process, so that the laser ultrasonic detection technology has the characteristic of non-contact compared with the traditional ultrasonic detection mode. In addition, the pulse laser beam can be obliquely incident to the surface of the structure in a longer distance and a larger angle range for excitation and reception of ultrasonic waves, and the automatic detection of a complex profile structure is easy to realize. The hidden corrosion is visualized and quantified through advanced nondestructive evaluation, and the method is important for detecting the corrosion position, quantifying the corrosion size and depth, ensuring the structural safety and reducing the service life cost.
In addition, lamb wave (Lamb wave) -based detection techniques have long been an important technique for detecting, locating and identifying lesions in structures. As Lamb waves can interact with the damaged part of the material in the propagation process to contain rich information, and no obvious dissipation exists, the Lamb waves can carry damage information to propagate a long distance, and the detection of a large-area test piece is facilitated. The time-space wave field data in the whole scanning area can be obtained by scanning and receiving Lamb wave signals in space with a certain step length by using laser. The interaction process between Lamb waves and structural features or damage at different moments can be intuitively seen through the frame-by-frame playback of the guided wave field, wave field signals are further analyzed through a damage imaging technology, and quantitative detection of damage in a structure can be achieved. In recent years, various damage imaging methods have been developed, but most of the research has focused on planar localization and morphology recognition of damage, for example, a Lamb wave damage detection method considering crack orientation disclosed in chinese patent publication No. CN109632958A (publication date is 16 of 2019), and less research has been conducted in the prior art on depth recognition of damage.
In conclusion, quantitative information of the damage in the depth direction has important significance for damage evaluation and later maintenance, and detection and analysis means for the damage in the depth direction are lacking in the prior art.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides a damage detection method, a system, a medium and equipment based on the litz transformation, wherein the damage detection method based on the litz transformation comprises the following steps:
s10: converting an original wave field signal containing damage information into a frequency domain wave field signal, and selecting a Shan Pinpin domain wave field signal corresponding to a main frequency;
s20: obtaining a complex domain wave field analysis signal corresponding to the Shan Pinpin domain wave field signal by performing litz transformation on the Shan Pinpin domain wave field signal;
s30: obtaining original spatial phase information of the Shan Pinpin domain wave field signal by performing a phase solution on the complex domain wave field analytic signal;
s40: the original spatial phase information is subjected to phase unwrapping to obtain a real spatial phase;
s50: obtaining space wave number information by carrying out bias derivative solution in the orthogonal direction on the real space phase;
s60: comparing the space wave number information with a dispersion curve of a corresponding material and frequency to obtain effective plate thickness information corresponding to the space wave number information;
s70: and obtaining readable information of the damage information according to the effective plate thickness information, wherein the readable information comprises damage depth information.
In one embodiment, the step S10 includes the following steps:
s11: the original wave field information comprises a space-time wave field signal w (x, y, t), and the frequency domain wave field signal w (x, y, f) is obtained by performing one-dimensional Fourier transform on the space-time wave field signal w (x, y, t);
s12: selecting a dominant frequency f from the frequency domain wave field signal w (x, y, f) 0 Corresponding Shan Pinpin domain wave field signal w (x, y, f 0 )。
In one embodiment, the step S20 includes: for the Shan Pinpin domain wave field signal w (x, y, f 0 ) Performing a litz transformation to solve the Shan Pinpin domain wave field signal w (x, y, f) 0 ) Constituent part w of the corresponding complex domain wavefield parsing signal m (x,y,t)＝[w(x,t,f 0 ),w x (x,y,f 0 ),w y (x,y,f 0 )]；
The first transformation kernel of the litz transformation comprises
The second transformation kernel of the litz transformation comprises
In an embodiment, said original spatial phase information in said step S30 is defined by vectorization of said complex domain wave field resolution signalIn which
In one embodiment, the step S40 includes the steps of:
s41: a reliability matrix R is constructed which,
wherein
wherein ,
wherein The phase value representing the coordinate position, and the function gamma (x) is used for obtaining the remainder of the variables x and 2 pi;
s42: solving reliability parameters of boundaries of coordinate points of a space according to the reliability matrix, wherein the value of the reliability parameters is the sum of reliability values of the coordinate points at two sides of the boundary;
s43: and performing phase unwrapping according to paths from large to small of the reliability parameters of the boundaries of the coordinate points.
In an embodiment, the step S40 further includes, after the step S43
Step S44: phase supplementing the blurred phase in the inverse trigonometric function to obtain the real phase in space
In one embodiment, the spatial wavenumber information in the step S50 includes a modulus value of a wavenumber vector of each coordinate point in space;
the wave number vector wherein kx ,k y Respectively the spatial true phases +.>Deviation from two orthogonal directions, i.e. +.>
The invention also provides a damage detection system based on the litz transformation, which comprises
The conversion module is used for converting the original wave field signal containing the damage information into a frequency domain wave field signal and selecting a Shan Pinpin domain wave field signal corresponding to the main frequency;
the litz transformation module is used for carrying out litz transformation on the Shan Pinpin domain wave field signal so as to obtain a complex domain wave field analysis signal corresponding to the Shan Pinpin domain wave field signal;
the phase solving module is used for carrying out phase solving on the complex domain wave field analysis signals to obtain original spatial phase information of the Shan Pinpin domain wave field signals;
the phase unwrapping module is used for unwrapping the phase of the original spatial phase information to obtain a real spatial phase;
the wave number solving module is used for carrying out bias guide solving in the orthogonal direction on the real space phase to obtain space wave number information;
the plate thickness information acquisition module is used for comparing the space wave number information with a dispersion curve of a corresponding material and frequency to acquire effective plate thickness information corresponding to the space wave number information;
and the readable information acquisition module obtains readable information of the damage information through the effective plate thickness information, wherein the readable information comprises damage depth information.
The present invention also provides a computer readable storage medium storing computer instructions which, when executed by a processor, implement the litz transformation-based impairment detection method as set forth in any one of the above.
The present invention also provides a computer device comprising at least one processor, and a memory communicatively coupled to the processor, wherein the memory stores instructions executable by the at least one processor to cause the processor to perform the litz transformation-based impairment detection method as set forth in any one of the above.
Based on the above, compared with the prior art, the damage detection method based on the litz transformation provided by the invention utilizes the abundant information contained in the guided wave place represented by the analysis signal to embody damage information. The resolved signals derived from the litz transformation are used to obtain the spatial orientation, phase and amplitude of the reconstructed guided wave field. And spatially deriving the phase from the two coordinates to obtain a spatial wavenumber vector. The magnitude of the spatial wave number vector obtained by the litz transformation represents the spatial wave number value pointing in the propagation direction at each point of the control. The method can be used for relatively complex geometric structures by analyzing the phase information of the signal through the wave field, and evaluating the morphology and the position of the damage by combining the advantages of an algorithm and Lamb waves so as to obtain accurate damage depth information.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
For a clearer description of embodiments of the invention or of the solutions of the prior art, the drawings that are needed in the description of the embodiments or of the prior art will be briefly described, it being obvious that the drawings in the description below are some embodiments of the invention, and that other drawings can be obtained from them without inventive effort for a person skilled in the art; the positional relationships described in the drawings in the following description are based on the orientation of the elements shown in the drawings unless otherwise specified.
FIG. 1 is a schematic flow chart of a damage detection method based on the litz transformation provided by the invention;
FIG. 2 is a schematic flow chart of step S10 and step S40 according to the embodiment of the present invention;
FIG. 3 is a schematic diagram of spatial phase unwrapping;
FIG. 4 is a graph showing a plate dispersion curve according to an embodiment;
FIG. 5 is a waveform diagram of a flaw detection in a simulation embodiment;
FIG. 6 is a schematic diagram of the effective plate thickness of the simulation embodiment.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention; the technical features designed in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that all terms used in the present invention (including technical terms and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs and are not to be construed as limiting the present invention; it will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The following is a description of specific examples.
The invention provides a damage detection method based on litz transformation, which refers to fig. 1 and comprises the following steps:
s10: converting an original wave field signal containing damage information into a frequency domain wave field signal, and selecting a Shan Pinpin domain wave field signal corresponding to a main frequency;
s20: obtaining a complex domain wave field analysis signal corresponding to the Shan Pinpin domain wave field signal by performing litz transformation on the Shan Pinpin domain wave field signal;
s30: obtaining original spatial phase information of the Shan Pinpin domain wave field signal by performing a phase solution on the complex domain wave field analytic signal;
s40: the original spatial phase information is subjected to phase unwrapping to obtain a real spatial phase;
s50: obtaining space wave number information by carrying out bias derivative solution in the orthogonal direction on the real space phase;
s60: comparing the space wave number information with a dispersion curve of a corresponding material and frequency to obtain effective plate thickness information corresponding to the space wave number information;
s70: and obtaining readable information of the damage information according to the effective plate thickness information, wherein the readable information comprises damage depth information.
Preferably, the readable information further includes lesion location and morphology information.
Specifically, for example, after obtaining a wave field original signal containing damage information by Lamb wave, processing by several main steps is required in order to analyze depth information of a defect by a time-space domain signal. As shown in fig. 2, first, step S10 includes the following steps:
s11: the original wave field information comprises a space-time wave field signal w (x, y, t), and the frequency domain wave field signal w (x, y, f) is obtained by performing one-dimensional Fourier transform on the space-time wave field signal w (x, y, t);
s12: selecting a dominant frequency f from the frequency domain wave field signal w (x, y, f) 0 Corresponding Shan Pinpin domain wave field informationNumber w (x, y, f) 0 ) Preferably, the dominant frequency f 0 Is the excitation frequency.
Then S20, the selected Shan Pinpin domain wave field signal w (x, y, f 0 ) Performing litz transformation and constructing an analytic signal R [ w (x, y, f) corresponding to the single-frequency wave field 0 )]. For single frequency domain wave field signals w (x, y, f 0 ) The first transformation kernel of the litz transformation in the space-time domain isThe second transformation kernel of the litz transformation comprises +.>W (x, y, f) can be solved by the litz transformation 0 ) Component w of corresponding complex domain wavefield resolution signal m (x,y,t)＝[w(x,y,f 0 ),w x (x,y,f 0 ),w y (x,t,f 0 )]。
From the vectorized definition of the resolved signal, the vertex angle is knownThe phase representing the local is the structural information description of the image, the vertex angle which can be defined by vectorization of the complex domain wave field resolved signal +.>Is representative of the original spatial phase information. Step S30 thus solves the original spatial phase information of the single frequency wavefield by,
next, in step S40, since the phase is solved by the wave field analysis signal, and the complex-to-phase expression has periodicity, the phase range of the litz transformation is between 0 and pi when the phase is solved, the value is taken by taking 2pi as a mode, and the difference between the true value and the calculated value exists due to the phase stacking. Obtaining an accurate phase is a key step in achieving detection, so that unwrapping reduction is required for the phase, and the unwrapped phase is shown in fig. 3 (a). There are two main problems in unwrapping, the selection of the reliability function and the design of the phase unwrapped path, and in order to select a reasonable unwrapped path, the reliability function is first defined.
Specifically, steps S41-S43 shown in FIG. 2 are included, and in S41, the phase values of each point are converted into corresponding reliability parameters to form a reliability matrix as shown in the following formulaWherein D is defined by the formula
Wherein each part is respectively
wherein The phase value representing the coordinate position, the function gamma (x) is used to find the remainder of the variables x and 2pi.
Then, in S42, the reliability parameters of the boundary of each coordinate point in the space are solved according to the reliability matrix, and the value of the reliability parameters is the sum of the reliability values of the coordinate points at two sides of the boundary.
Then, in S43, phase unwrapping is performed according to the paths from large to small of the reliability parameters of the boundaries of the coordinate points.
Preferably, in an embodiment, as shown in fig. 2, step S40 further includes step S44 of phase supplementing the phase blurred in the inverse trigonometric function to obtain the spatially real phaseFig. 3 (b) shows the phase after disentanglement reduction.
From the phase point of view, the wave number is then understood to be the rate of change of phase with distance. Therefore, the unwrapped phase is biased in the orthogonal direction, the wave number value of each position of the space wave field can be obtained, and the wave number change characteristic of the guided wave in the propagation process is reflected.
Specifically, the spatial wave number information in step S50 includes the modulus value of the wave number vector of each coordinate point in space;
the wave number vector wherein kx ,k y Respectively the spatial true phases +.>Deviation from two orthogonal directions, i.e. +.>
Thus, spatial wavenumber information
When Lamb waves propagate in plates of different thicknesses and different materials, the frequency dispersion curve reveals the relation between wave numbers and frequencies, and as the frequency dispersion curve of Lamb waves is only related to the frequency-thickness product of the materials, the frequency-wave number corresponding relation changes along with the plate thickness, so that the thickness of the corroded residual plate can be determined by utilizing the solved relation between the space wave numbers and the plate thickness, and further the corrosion depth is obtained, and the quantification of corrosion damage in the depth direction is realized. Taking the delamination damage as an example, at the delamination position, the subplate (one consisting of the plate at the upper part of the delamination and the plate at the lower part of the delamination) supports the propagating Lamb wave, and the effective thickness of the detection is the thickness of each subplate. In other words, the effective thickness is the thickness detected by the wave field information, which corresponds to the thickness of the plate for an original plate without damage; if stratification is present, the effective thickness fed through the wavefield is equal to the thickness between the stratification interface and the sweep interface. As shown in FIG. 4, the dispersion curve of the aluminum plate with the thickness of 2mm is shown, and the relationship between the plate thickness and the wave number at different frequencies can be obtained according to the dispersion of the aluminum plates with different thicknesses in the step S60.
Preferably, step S70 may reveal readable information of the damage to the sheet material based on the effective sheet thickness information of the sheet material, wherein the readable information includes damage depth information, azimuth and morphology information.
The invention also provides simulation verification of the method, and the verification uses abaqus software to simulate the propagation process of the guided wave. The length, width and height dimensions of the set simulation aluminum plate are respectively 400mm, 400mm and 2mm, the damage form is a square corrosion damage of 20mm, the square corrosion damage is specifically realized in a way that the area with the dimension of 20mm, the depth of 1mm is set as the break of a finite element node, and the defect represents the lack of fusion of stacking of a certain area in the aluminum plate. The lower left corner end point of the sensing area is set as the origin of coordinates, and the sensing area covers a rectangular area passing from the origin of coordinates in the figure to coordinates (80, 80). The center point coordinates of the corrosion defect are set to (45, 40). The time step of the simulation model was set to 1us and the grid size was set to 1 x 1mm. The material properties of the aluminum used for modeling are shown in table 1, where E is young's modulus, v represents poisson's ratio, and ρ represents material density. Lamb wave excitation was performed using a five-peak signal of 100khz as the dominant frequency, and as can be seen in fig. 5, lamb wave interacts with the lesion as it passes through the lesion area. The damage image after the algorithm identification is shown in fig. 5, and it can be seen that the wave number value in the square damage area is obviously larger than that in the non-damage area, so that the position and the form of the damage are accurately represented. And the effective thickness is displayed, as shown in fig. 6, the effective thickness of the damaged area is identified as 1mm, and the effective thickness of the non-damaged area is identified as 2mm, namely the effective thickness is basically coincident with the damage depth and the plate thickness preset by simulation.
| Attributes of | Parameters (parameters) | Unit (B) |
| E | 70 | Gpa |
| v | 0.33 | |
| ρ | 2700 | kg·m -3 |
TABLE 1
The invention also provides a damage detection system based on the litz transformation, which comprises
The conversion module is used for converting the original wave field signal containing the damage information into a frequency domain wave field signal and selecting a Shan Pinpin domain wave field signal corresponding to the main frequency;
the litz transformation module is used for carrying out litz transformation on the Shan Pinpin domain wave field signal so as to obtain a complex domain wave field analysis signal corresponding to the Shan Pinpin domain wave field signal;
the phase solving module is used for carrying out phase solving on the complex domain wave field analysis signals to obtain original spatial phase information of the Shan Pinpin domain wave field signals;
the phase unwrapping module is used for unwrapping the phase of the original spatial phase information to obtain a real spatial phase;
the wave number solving module is used for carrying out bias guide solving in the orthogonal direction on the real space phase to obtain space wave number information;
the plate thickness information acquisition module is used for comparing the space wave number information with a dispersion curve of a corresponding material and frequency to acquire effective plate thickness information corresponding to the space wave number information;
and the readable information acquisition module obtains readable information of the damage information through the effective plate thickness information, wherein the readable information comprises damage depth information.
The present invention also provides a computer readable storage medium storing computer instructions which, when executed by a processor, implement the litz transformation-based impairment detection method as set forth in any one of the above.
In summary, compared with the prior art, the damage detection method based on the litz transformation provided by the invention utilizes the abundant information contained in the guided wave place represented by the analysis signal to represent damage information. The resolved signals derived from the litz transformation are used to obtain the spatial orientation, phase and amplitude of the reconstructed guided wave field. And spatially deriving the phase from the two coordinates to obtain a spatial wavenumber vector. The magnitude of the spatial wave number vector obtained by the litz transformation represents the spatial wave number value pointing in the propagation direction at each point of the control. The method can be used for relatively complex geometric structures by analyzing the phase information of the signal through the wave field, evaluating the morphology and the position of the damage by combining the advantages of an algorithm and Lamb waves, and relatively accurately obtaining the depth information of the damage.
In specific implementation, the computer readable storage medium is a magnetic Disk, an optical Disk, a Read-only Memory (ROM), a random access Memory (Random Access Memory, RAM), a Flash Memory (Flash Memory), a Hard Disk (HDD) or a Solid State Drive (SSD); the computer readable storage medium may also include a combination of the above types of memory.
The present invention also provides a computer device comprising at least one processor, and a memory communicatively coupled to the processor, wherein the memory stores instructions executable by the at least one processor to cause the processor to perform the litz transformation-based impairment detection method as set forth in any one of the above.
In particular, the number of processors may be one or more, and the processors may be central processing units (Central Processing Unit, CPU). The processor may also be any other general purpose processor, digital signal processor (Digital Signal Processor, DSP), application specific integrated circuit (Application Specific Integrated Circuit, ASIC), field programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The memory may be communicatively coupled to the processors via a bus or other means, the memory storing instructions executable by the at least one processor to cause the processor to perform the litz transformation-based impairment detection method as set forth in any one of the preceding claims.
In addition, it should be understood by those skilled in the art that although many problems exist in the prior art, each embodiment or technical solution of the present invention may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.
Although terms such as litz transformation, shan Pinpin domain wave field signals, raw spatial phase information, phase unwrapping, spatially true phase, spatial wavenumber information, effective plate thickness information, and readable information are more used herein, the possibility of using other terms is not precluded. These terms are used merely for convenience in describing and explaining the nature of the invention; they are to be interpreted as any additional limitation that is not inconsistent with the spirit of the present invention; the terms first, second, and the like in the description and in the claims of embodiments of the invention and in the above-described figures, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. The damage detection method based on the litz transformation is characterized by comprising the following steps of:
s10: obtaining an original wave field signal containing damage information through a Lamb wave signal on an acquisition board, wherein the original wave field signal contains a time-space domain signal, converting the time-space domain signal in the original wave field signal into a frequency domain wave field signal, and selecting a Shan Pinpin domain wave field signal corresponding to a main frequency;
s20: obtaining a complex domain wave field analysis signal corresponding to the Shan Pinpin domain wave field signal by performing litz transformation on the Shan Pinpin domain wave field signal;
s30: obtaining original spatial phase information of the Shan Pinpin domain wave field signal by performing a phase solution on the complex domain wave field analytic signal;
s40: the original spatial phase information is subjected to phase unwrapping to obtain a real spatial phase;
s50: obtaining space wave number information by carrying out bias derivative solution in the orthogonal direction on the real space phase;
s60: comparing the space wave number information with a dispersion curve of a corresponding material and frequency to obtain effective plate thickness information corresponding to the space wave number information;
s70: and obtaining readable information of the damage information according to the effective plate thickness information, wherein the readable information comprises damage depth information.
2. The litz transformation-based impairment detection method of claim 1, wherein: the step S10 comprises the following steps:
s11: the raw wave field information comprises a space-time wave field signalBy applying to the space-time wave field signalPerforming one-dimensional Fourier transform to obtain the frequency domain wave field signal +.>;
S12: from the frequency domain wave field signalThe main frequency is selected out>Corresponding Shan Pinpin domain wave field signal。
3. The litz transformation-based impairment detection method of claim 2, wherein: the step S20 includes: for the Shan Pinpin domain wave field signalSolving the Shan Pinpin domain wave field signal by performing a litz transformationConstituent parts of the corresponding complex domain wavefield resolution signal；
The first transformation kernel of the litz transformation comprises;
The second transformation kernel of the litz transformation comprises。
4. The litz transformation-based impairment detection method of claim 3, wherein: the original spatial phase information in the step S30 is defined by vectorization of the complex domain wave field analysis signal to define a vertex angleIn which
。
5. The litz transformation-based impairment detection method of claim 1, wherein: the step S40 includes the steps of:
s41: constructing a reliability matrix，
，
wherein ；
wherein ,
；
；
；
；
wherein Phase value representing the coordinate position, function->For determining the variable->And->Remainder of (2);
s41: solving reliability parameters of boundaries of coordinate points of a space according to the reliability matrix, wherein the value of the reliability parameters is the sum of reliability values of the coordinate points at two sides of the boundary;
s43: and performing phase unwrapping according to paths from large to small of the reliability parameters of the boundaries of the coordinate points.
6. The litz transformation-based impairment detection method of claim 5, wherein: the step S40 further comprises, after the step S43
Step S44: phase supplementing the blurred phase in the inverse trigonometric function to obtain the real phase in space。
7. The litz transformation-based impairment detection method of claim 6, wherein: the spatial wave number information in the step S50 includes a modulus value of a wave number vector of each coordinate point in space;
the wave number vector, wherein />Respectively the spatial true phases +.>Deviation from two orthogonal directions, i.e. +.>，/>。
8. A litz transformation-based damage detection system, characterized by: comprising
The conversion module is used for obtaining an original wave field signal containing damage information through Lamb wave signals on the acquisition board, the original wave field signal contains time-space domain signals, converting the time-space domain signals in the original wave field signal into frequency domain wave field signals through the conversion module, and selecting Shan Pinpin domain wave field signals corresponding to main frequencies;
the litz transformation module is used for carrying out litz transformation on the Shan Pinpin domain wave field signal so as to obtain a complex domain wave field analysis signal corresponding to the Shan Pinpin domain wave field signal;
the phase solving module is used for carrying out phase solving on the complex domain wave field analysis signals to obtain original spatial phase information of the Shan Pinpin domain wave field signals;
the phase unwrapping module is used for unwrapping the phase of the original spatial phase information to obtain a real spatial phase;
the wave number solving module is used for carrying out bias guide solving in the orthogonal direction on the real space phase to obtain space wave number information;
the plate thickness information acquisition module is used for comparing the space wave number information with a dispersion curve of a corresponding material and frequency to acquire effective plate thickness information corresponding to the space wave number information;
and the readable information acquisition module obtains readable information of the damage information through the effective plate thickness information, wherein the readable information comprises damage depth information.
9. A computer-readable storage medium, characterized by: the computer readable storage medium stores computer instructions which, when executed by a processor, implement the litz transformation based impairment detection method according to any one of claims 1-7.
10. A computer device, characterized by: comprising at least one processor, and a memory communicatively coupled to the processor, wherein the memory stores instructions executable by the at least one processor to cause the processor to perform the litz transformation-based impairment detection method according to any one of claims 1-7.
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