A method and system for detecting and locating crack damage in concrete slabs

Abstract

This invention provides a method and system for detecting and locating crack damage in concrete slabs, relating to the field of structural health monitoring technology in civil engineering. The method involves collecting guided wave signals using a ring-shaped sensor array. First, the flight time of the scattered waves is extracted, and a flight time delay factor is calculated to construct a probabilistic damage spatial distribution function reflecting the geometric location of the damage. Next, a signal difference characteristic factor characterizing the signal waveform differences is used to collaboratively correct and weight the above distribution. Finally, by optimizing the damage probabilities of all detection paths through pairwise multiplication and summation, the signal-to-noise ratio and spatial resolution of the imaging signal are significantly enhanced. This invention effectively solves the problem of missed detection of damage in the array edge region caused by the limited number of effective signal paths in traditional ring-array-based probabilistic detection methods, achieving high-precision location and visualization imaging of crack damage in concrete slabs, especially damage at the array edge.

Description

Technical Field

[0001] This invention relates to the field of structural health monitoring technology in civil engineering, and in particular to a method and system for detecting and locating crack damage in concrete slabs. Background Technology

[0002] Concrete structures are widely used in various construction projects due to their advantages such as good durability, high strength, and strong plasticity. However, under the long-term influence of the environment and loads, crack damage is inevitable. Severe damage can reduce the residual strength of the material and the load-bearing capacity of the structure, thus posing serious safety hazards and seriously threatening the integrity and safety of the building structure. Therefore, developing an efficient and accurate crack damage detection and location method is crucial for timely health assessment and maintenance of structures.

[0003] Among numerous nondestructive testing (NDT) techniques, active detection technology based on Lamb waves has shown significant potential in structural health monitoring due to its advantages such as long propagation distance, high sensitivity, fast response speed, low attenuation, and strong anti-interference ability. In recent years, Lamb wave damage detection methods combining probabilistic models and time-of-flight analysis have received widespread attention. This method detects and locates damage by analyzing signal characteristics. However, existing methods often employ ring sensor arrays combined with traditional probabilistic damage detection reconstruction algorithms (such as the RAPID algorithm). While these methods can effectively detect damage within the sensor array's internal region, their detection capability heavily depends on the number of effective detection paths. For crack damage located at or near the edge of the sensor array, the significantly reduced number of available signal paths and insufficient signal feature information prevent the algorithm from reliably detecting and locating damage at that location, resulting in a high risk of missed detections. Summary of the Invention

[0004] To address the high risk of missed detection in existing probabilistic detection methods based on ring arrays due to the limited number of effective signal paths in the array edge region, this invention proposes a concrete slab crack damage detection and localization method and system that integrates signal difference characteristics and time-of-flight features. By constructing a novel probabilistic damage spatial distribution function and introducing a signal difference characteristic factor for collaborative correction, the imaging resolution and localization accuracy are significantly improved through probability multiplication and optimization. In particular, it effectively achieves reliable detection of crack damage at the edge of the sensor array.

[0005] To achieve the above objectives, a first aspect of the present invention provides a method for detecting and locating crack damage in a concrete slab, comprising: The guided wave signals collected by the ring sensor array arranged on the surface of the concrete slab are acquired, including non-destructive signals and lossy signals. The non-destructive signals are the signals received by the receiver after the exciter emits Lamb waves in the healthy concrete slab, and the lossy signals are the signals received by the receiver after the exciter emits Lamb waves in the cracked concrete slab. Based on the lossless and lossy signals, the scattered signal of each detection path is calculated, and the envelope of the scattered signal is extracted to obtain the flight time of the scattered wave. Based on the flight time of the scattered wave, calculate the flight time delay factor of each pixel for each detection path; Based on the time-of-flight delay factor, a probabilistic damage spatial distribution function is constructed, and combined with the signal difference characteristic factor, the damage probability of each pixel for each detection path is calculated. The final damage probability distribution of a pixel is obtained by multiplying the damage probabilities of each pixel under different detection paths in pairs and then summing them. Damage imaging is performed based on the final damage probability distribution, and the location information of the crack damage is output.

[0006] Furthermore, the acquisition of the guided wave signal includes: The sensors in the ring sensor array are used sequentially as exciters to emit Lamb wave signals, and the remaining sensors are used as receivers to receive the signals. Collect non-destructive signals in a healthy state and destructive signals in a state containing crack damage; The sensor array consists of multiple piezoelectric sensors evenly arranged on a ring array.

[0007] Furthermore, the calculation of the flight time of the scattered wave includes: subtracting the response signal in the damaged structure from the baseline signal in the healthy structure to obtain the scattered signal; Perform a Hilbert transform on the scattered signal to extract its envelope; The time corresponding to the first peak point of the envelope is taken as the flight time of the scattered wave.

[0008] Furthermore, the formula for calculating the flight time delay factor is as follows: ; in, This represents the theoretical flight time for the pixel corresponding to the current detection path. This represents the flight time of the scattered wave along the current detection path.

[0009] Furthermore, the formula for calculating the signal difference characteristic factor is as follows: ; in, For the first The detection path contains a non-destructive signal. For the first The lossy signal of the detection path, where Cov represents the covariance and σ represents the standard deviation.

[0010] Furthermore, the formula for calculating the final damage probability distribution is as follows: ; in, For pixels For the first The probability value of damage along the detection path. This represents the total number of detection paths.

[0011] A second aspect of the present invention provides a concrete slab crack damage detection and localization system, comprising: The sensor array module is used to arrange a ring sensor array on the surface of a concrete slab to excite Lamb wave signals and receive the propagated signals. The signal acquisition module is used to control the excitation and signal acquisition of the sensor array to obtain lossless signals and lossy signals; the lossless signal is the signal received by the receiver after the exciter emits a Lamb wave in a healthy concrete slab, and the lossy signal is the signal received by the receiver after the exciter emits a Lamb wave in a concrete slab with crack damage. The signal processing module is used to calculate the scattered signal of each detection path based on the lossless signal and the lossy signal, extract the envelope of the scattered signal, and obtain the flight time of the scattered wave; based on the flight time of the scattered wave, calculate the flight time delay factor of each pixel for each detection path; based on the flight time delay factor, construct a probability damage spatial distribution function, and combine it with the signal difference characteristic factor to calculate the damage probability of each pixel for each detection path; multiply the damage probabilities of each pixel under different detection paths pairwise and then sum them to obtain the final damage probability distribution of the pixel. The imaging module is used to perform damage imaging based on the final damage probability distribution and output the location information of the crack damage. The display module is used to display the imaging results of crack damage.

[0012] A third aspect of the present invention provides an electronic device including a memory, a processor, and a program stored in the memory and running on the processor, wherein the processor executes the program to implement the steps in the concrete slab crack damage detection and localization method as described in the first aspect of the present invention.

[0013] A fourth aspect of the present invention provides a computer-readable storage medium having a program stored thereon that, when executed by a processor, implements the steps in the concrete slab crack damage detection and localization method as described in the first aspect of the present invention.

[0014] A fifth aspect of the present invention provides a computer program product comprising software code, wherein the program in the software code performs the steps of the concrete slab crack damage detection and localization method as described in the first aspect of the present invention.

[0015] Compared with the prior art, the concrete slab crack damage detection and location method and system provided by the present invention have the following beneficial effects: (1) This invention integrates and synergistically drives time-of-flight delay information and signal waveform difference information by constructing a probabilistic damage spatial distribution function, combining it with a signal difference characteristic factor, and summing the damage probabilities pairwise. The probabilistic damage spatial distribution function is constructed based on the time-of-flight delay factor, which can initially reflect the spatial distribution of damage probability; the signal difference characteristic factor weights the detection results of each path from the perspective of waveform correlation. The combination of the two makes the information provided by each path richer and more reliable, even when there are fewer effective paths in the edge region. The subsequent probability multiplication and summation operation (summing the pairwise multiplication) further amplifies the signal characteristics that consistently point to the true damage location in all detection paths, while suppressing noise and false alarms, thereby significantly enhancing the signal-to-noise ratio and positioning accuracy of edge damage detection under limited path conditions, and realizing the effective detection of array edge crack damage.

[0016] (2) This invention calculates the flight time of the scattered wave and its delay factor, accurately extracts the arrival time of the scattered wave, and calculates its deviation from the theoretical flight time, thereby realizing the geometric constraint on the damage location. The damage location problem is transformed into a spatial search problem based on the difference in signal arrival time. The flight time delay factor quantifies the proximity of each pixel point to the real damage point, providing an accurate physical basis for subsequent probability distribution calculation, thus improving the robustness and accuracy of the entire location method.

[0017] (3) The sensor array is arranged in a ring array, and the signal acquisition and processing adopt a specific excitation and reception mode, which can systematically acquire the guided wave response signal of the entire structure area, providing a complete data foundation for subsequent probability multiplication and optimization and high-precision positioning. Attached Figure Description

[0018] The accompanying drawings, which form part of this disclosure, are used to provide a further understanding of this disclosure. The illustrative embodiments of this disclosure and their descriptions are used to explain this disclosure and do not constitute an undue limitation of this disclosure.

[0019] Figure 1 This is a flowchart of the concrete slab crack damage detection and positioning method provided in Embodiment 1 of the present invention; Figure 2This is a schematic diagram of the overall architecture of the concrete slab crack damage detection and positioning method provided in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the sensor array arrangement provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the principle of the crack damage imaging and localization algorithm based on the coordinated driving of signal difference characteristics and time of flight provided in Embodiment 1 of the present invention; Figure 5 This is an image showing the crack damage detection imaging and localization results in simulation, provided in Embodiment 1 of the present invention. Figure 6 This is an architecture diagram of the concrete slab crack damage detection and positioning system provided in Embodiment 2 of the present invention. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0023] All data acquisition in this embodiment is carried out in accordance with laws and regulations and with user consent, and the data is used legally.

[0024] Example 1 like Figure 1 This embodiment provides a method for detecting and locating crack damage in concrete slabs, including: The guided wave signals collected by the ring sensor array arranged on the surface of the concrete slab are acquired, including non-destructive signals and lossy signals. The non-destructive signals are the signals received by the receiver after the exciter emits Lamb waves in the healthy concrete slab, and the lossy signals are the signals received by the receiver after the exciter emits Lamb waves in the cracked concrete slab. Based on the lossless and lossy signals, the scattered signal of each detection path is calculated, and the envelope of the scattered signal is extracted to obtain the flight time of the scattered wave. Based on the flight time of the scattered wave, calculate the flight time delay factor of each pixel for each detection path; Based on the time-of-flight delay factor, a probabilistic damage spatial distribution function is constructed, and combined with the signal difference characteristic factor, the damage probability of each pixel for each detection path is calculated. The final damage probability distribution of a pixel is obtained by multiplying the damage probabilities of each pixel under different detection paths in pairs and then summing them. Damage imaging is performed based on the final damage probability distribution, and the location information of the crack damage is output.

[0025] The core of this method lies in the synergistic utilization of the signal's time-of-flight characteristics and waveform difference characteristics, and the enhancement of detection capability through probability multiplication and optimization. Existing methods (such as the RAPID algorithm) mainly rely on signal differences, resulting in insufficient information at array edges due to the limited number of paths. This invention introduces a probabilistic damage spatial distribution function based on the time-of-flight delay factor, providing each pixel with geometric constraint information from the signal propagation time. This is equivalent to adding a new, independent dimension for measuring the damage probability of each detection path. Subsequently, this distribution is multiplied by the traditional signal difference characteristic factor (SDC), achieving the fusion and mutual correction of time-domain and waveform-domain features. Finally, instead of a simple summation, the damage probabilities of each path are multiplied pairwise and then summed: only the positions commonly pointed to by most paths have their probability products amplified, while the contributions of noisy or highly random paths are relatively suppressed. This series of operations works synergistically to significantly improve the utilization efficiency of limited path information, thereby effectively overcoming the detection challenge caused by the reduced number of paths at array edges.

[0026] Specifically, acquiring the guided wave signal includes: The sensors in the ring sensor array are used sequentially as exciters to emit Lamb wave signals, and the remaining sensors are used as receivers to receive the signals. Collect non-destructive signals in a healthy state and destructive signals in a state containing crack damage; The sensor array consists of multiple piezoelectric sensors evenly arranged on a ring array.

[0027] By employing a ring-shaped sensor array and implementing a full-path excitation-reception strategy, the guided wave response of all possible regions of the structure (including the center and edges) can be systematically acquired. The uniformly arranged sensors ensure the coverage uniformity of the detection network, while the sequential excitation and subsequent reception mode can acquire the propagation signals between all sensor pairs (a total of N*(N-1) / 2 paths), providing the maximum amount of raw data for subsequent processing and laying the data foundation for achieving high-precision, full-coverage detection.

[0028] Specifically, the calculation of the flight time of the scattered wave includes: subtracting the response signal in the damaged structure from the baseline signal in the healthy structure to obtain the scattered signal; Perform a Hilbert transform on the scattered signal to extract its envelope; The time corresponding to the first peak point of the envelope is taken as the flight time of the scattered wave.

[0029] Signal subtraction aims to separate the scattered wave component caused by damage, removing the background response of the healthy structure. Hilbert transform extraction of the envelope effectively overcomes the distortion caused by the dispersion characteristics of Lamb waves, clarifying the arrival time of the wave packet. The time corresponding to the first peak point of the envelope is selected as the time of flight of the scattered wave because this point usually corresponds to the strongest and most directly propagating scattered wavefront, best reflecting the geometric relationship between the damage point and the sensor. Based on this step, the physical quantity directly related to the damage location—time delay—is accurately extracted from the complex original signal, providing accurate input for the subsequent construction of the probabilistic damage spatial distribution function.

[0030] Specifically, the formula for calculating the flight time delay factor is as follows: ; in, This represents the theoretical flight time for the pixel corresponding to the current detection path. This represents the flight time of the scattered wave along the current detection path.

[0031] Flight time delay factor It is the core bridge connecting geometric position and measurement time. Based on pixels The theoretical flight time is calculated based on the positions of the exciter and receiver (assuming the signal passes through that point). This is the time-of-flight of the scattered wave extracted from the actual signal. Theoretically, when the pixel happens to be the actual damage point, it should have... ,but . therefore, The smaller the absolute value, the closer the pixel matches the damage location reflected by the current detection path. This calculation formula cleverly transforms the damage localization problem into an optimization problem of minimizing time error, quantitatively expressing the probability of each pixel being a damage location (based on time matching degree), and providing a quantitative basis for constructing the probability distribution function.

[0032] Specifically, the formula for calculating the signal difference characteristic factor is as follows: ; in, For the first The detection path contains a non-destructive signal. For the first The lossy signal of the detection path, where Cov represents the covariance and σ represents the standard deviation.

[0033] Signal difference characteristic factor It retains the sensitivity to signal waveform changes found in traditional probabilistic detection methods. Its essence is to calculate health signals. With damage signals The correlation coefficient in the direct wave portion is calculated, and this correlation coefficient is subtracted from 1. When the signal changes significantly due to damage, the correlation coefficient decreases. A correlation coefficient approaching 1 indicates a high degree of confidence that the path "passes through damage"; when the signal remains unchanged, the correlation coefficient is close to 1. Approaching 0. This step pre-weights the effectiveness or contribution of each detection path from the perspective of signal similarity, which can initially screen out paths that are significantly affected by damage and reduce the weight of paths that are not affected by damage or are severely affected by noise in subsequent calculations, thereby improving the overall method's anti-interference ability.

[0034] Specifically, the formula for calculating the final damage probability distribution is as follows: ; in, For pixels For the first The probability value of damage along the detection path. This represents the total number of detection paths.

[0035] Probability multiplication and optimization is a key step in achieving high-resolution, high-contrast imaging. Traditional methods often simply sum the probabilities of multiple paths, which easily leads to a diffuse probability distribution and obscured damage areas. This invention employs a strategy of multiplying the probability values ​​of each pair of paths before summing them. Multiplication has a nonlinear amplification effect: for the true damage point, the probability of most paths multiplying... The values ​​are all relatively high, and their product will result in a very large number; however, for non-damaged points, as long as there is a path... When the value is low, the product will be small. The summation operation aggregates the consensus of all path combinations. This multiplication and summation operation is equivalent to finding the location supported by the most independent evidence (detection paths), which greatly enhances the signal-to-noise ratio and spatial resolution of the damaged image. It can clearly highlight the core location of the damage from the probability distribution map, which is especially helpful for identifying edge damage indicated by a few key paths in a probabilistic background.

[0036] In one specific embodiment, the method is implemented based on simulation experiments, such as... Figure 2 ,include: Signal acquisition: Build an experimental system, design a sensor array, collect sensor coordinate information, and obtain Lamb wave response signals from healthy and damaged structures as input.

[0037] Scattered wave flight time calculation: Calculate the residual signal of the signal received by each detection path, identify it as the scattered signal, and take the time corresponding to the first peak point of the scattered signal envelope as the flight time of the scattered wave.

[0038] Pixel-level damage probability distribution calculation (driven by signal difference characteristics and time-of-flight features): Calculate the damage probability of each pixel for each detection path.

[0039] Probability multiplication and detection imaging: The damage probability of each pixel for each detection path is multiplied in pairs and then summed to calculate the damage probability of each pixel. Based on this, damage imaging is performed, and the coordinates of the locked damage points are read.

[0040] The following is a detailed description of the method for detecting and locating cracks in concrete slabs, using specific embodiments, and includes the following steps: 1. Concrete slab model construction: The concrete slab model was constructed using the explicit time-integration finite element method, and the dynamic display module of the Explicit solver in ABAQUS simulation software was selected for simulation analysis. Considering both material properties and the computational speed of the finite element simulation, the concrete slab dimensions were set to 600mm × 600mm × 20mm. The model was constructed based on its material properties (mass density, elastic modulus, Poisson's ratio, mass damping coefficient, and stiffness damping coefficient). Examples of material parameters are shown in the table below. Table 1. Material Parameters of Concrete Slabs

[0041] Concrete slab models in both healthy and cracked states were constructed. A coordinate system was established with the lower left corner of the concrete slab as the origin. The coordinates of the crack damage center were (445.061mm, 340mm), the crack length was 30mm, the width was 1mm, and the crack was parallel to the y-axis.

[0042] 2. Sensor array arrangement: A ring-shaped sensor array is arranged on the surface of the concrete slab to form a relatively dense detection network. The sensor array consists of multiple sensors used to excite Lamb wave signals and receive the propagated signals. In a specific embodiment, the sensor array consists of 12 piezoelectric sensors with a diameter of 300 mm, uniformly attached to the surface of the concrete slab, arranged as follows: Figure 3 As shown.

[0043] 3. Signal data acquisition: The sparse triangulation acquisition method is used, where one sensor sequentially acts as an exciter to release a Lamb wave signal, and subsequent numbered sensors act as receivers to receive the signal propagated through the concrete slab, acquiring both lossless and lossy signals. In a specific embodiment, a sensor sequentially acts as an exciter to release a Lamb wave signal with a center frequency of 50kHz, and subsequent numbered sensors act as receivers to receive the signal, thereby acquiring signals from a total of 66 detection paths.

[0044] 4. Calculation of the time-of-flight delay of scattered waves: For each detection path, the damage signal is obtained by subtracting the baseline signal in the healthy structure from the response signal in the damaged structure: ; in, This represents the response signal in the damaged structure. This represents the baseline signal in a healthy structure. The signal is a scattered signal. Calculate the envelope of the scattered signal: ; The above describes the extraction of the envelope signal using the Hilbert transform. The Hilbert transform can be considered as the expression of the original function and the function... The convolution of the function, assuming the function obtained after Hilbert transform is... ,set up The real part is represented as The imaginary part is represented as The extracted envelope signal is .

[0045] 5. Calculation of the probabilistic damage spatial distribution function based on the time-of-flight delay factor: The time corresponding to the first peak point of the envelope signal of each detection path is extracted as the flight time ts of the scattered wave, such as in... Figure 4 middle, This represents the actual location of the damage point. Let be any pixel. For isotropic materials, for a given pixel... The actual propagation time of the signal wave passing through this point is the ratio of the sum of the distance from the excitation sensor location to this point and the distance from this point to the receiving sensor to the propagation speed. Therefore, the actual flight time of this point in a healthy state can be calculated. ; in, This corresponds to the actual flight time at point M. Let be the coordinates of a certain excitation sensor. Let be the coordinates of a certain receiving sensor. Group velocity.

[0046] The probability damage spatial distribution function is defined as follows: ; ; in, and These are scaling parameters that collectively control the size and distribution characteristics of the distribution area. It is usually set to 0.5. The flight time delay factor is defined as follows: ; in, The flight time of a certain point x on a certain detection path; This corresponds to the flight time of the scattered signal along the detection path. At that time, the two were close. The smaller the value, the closer the actual damage point is to the reference point M, and the greater the probability of damage occurring at point M. The larger the value, the less likely damage will occur at point M.

[0047] 6. The synergistic driving force of signal difference characteristic factors and probability impairment spatial distribution function: Calculate the value of a point with the number . Probabilistic damage spatial distribution of the detection path Next, the signal difference characteristic factor for each detection path signal needs to be calculated. This factor is then multiplied by the probability damage space distribution function, which includes the time-of-flight delay factor, to obtain the final damage probability for a given point. Simultaneously, the signal difference characteristic factor determines the reliability of the damage probability distribution and can eliminate interference from erroneous signals or noise in the scattered signal. Let the pixel-level damage probability of any reference point in the grid be... The signal difference characteristic factor of a certain path is Then it is defined as follows: ; Among them, the signal difference characteristic factor (SDC) is defined based on the degree of difference in the correlation coefficient of each pair of signals in the direct wave portion: ; 7. Probability multiplication and optimization of detection imaging: Based on the above formula, calculate each point Damage probability for each detection path The damage probability of this point for different detection paths is calculated by multiplying each pairwise, and then summing the results to obtain the final damage probability distribution of this point. The calculation formula is as follows: ; The final damage probability distribution is used for damage detection imaging, and the probability values ​​are converted into corresponding pixel color levels to intuitively display the location and extent of the damage.

[0048] Based on the above calculations, the imaging results of crack damage are as follows: Figure 5 As shown, the imaging result has positioning coordinates of (447.8 mm, 345.4 mm), with an error of (2.739 mm, 5.4 mm) compared to the actual crack damage center coordinates. The radial error is 6.05 mm, which is relatively small, indicating that the positioning method has high accuracy and reliability. Furthermore, the crack damage location set in this embodiment is at the edge of the circular sensor detection array, overcoming the limitation of traditional positioning methods that cannot detect damage at the array edge, and providing a novel technical solution for crack damage positioning and detection.

[0049] Example 2 like Figure 6 As shown, this embodiment provides a concrete slab crack damage detection and location system, including: The sensor array module is used to arrange a ring sensor array on the surface of a concrete slab to excite Lamb wave signals and receive the propagated signals. The signal acquisition module is used to control the excitation and signal acquisition of the sensor array to obtain lossless signals and lossy signals; the lossless signal is the signal received by the receiver after the exciter emits a Lamb wave in a healthy concrete slab, and the lossy signal is the signal received by the receiver after the exciter emits a Lamb wave in a concrete slab with crack damage. The signal processing module is used to calculate the scattered signal of each detection path based on the lossless signal and the lossy signal, extract the envelope of the scattered signal, and obtain the flight time of the scattered wave; based on the flight time of the scattered wave, calculate the flight time delay factor of each pixel for each detection path; based on the flight time delay factor, construct a probability damage spatial distribution function, and combine it with the signal difference characteristic factor to calculate the damage probability of each pixel for each detection path; multiply the damage probabilities of each pixel under different detection paths pairwise and then sum them to obtain the final damage probability distribution of the pixel. The imaging module is used to perform damage imaging based on the final damage probability distribution and output the location information of the crack damage. The display module is used to display the imaging results of crack damage.

[0050] Example 3 Embodiment 3 of the present invention provides an electronic device.

[0051] An electronic device includes a memory, a processor, and a program stored in the memory and running on the processor. When the processor executes the program, it implements the steps in the concrete slab crack damage detection and location method as described in Embodiment 1 of the present invention.

[0052] The detailed steps are the same as those of the concrete slab crack damage detection and location method provided in Example 1, and will not be repeated here.

[0053] Example 4 Embodiment 4 of the present invention provides a computer-readable storage medium.

[0054] A computer-readable storage medium having a program stored thereon, which, when executed by a processor, implements the steps in the concrete slab crack damage detection and localization method as described in Embodiment 1 of the present invention.

[0055] The detailed steps are the same as those of the concrete slab crack damage detection and location method provided in Example 1, and will not be repeated here.

[0056] Example 5 Embodiment 5 of the present invention provides a computer program product.

[0057] A computer program product includes software code, wherein the program in the software code performs the steps of the concrete slab crack damage detection and location method as described in Embodiment 1 of the present invention.

[0058] The detailed steps are the same as those of the concrete slab crack damage detection and location method provided in Example 1, and will not be repeated here.

[0059] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0060] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0061] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0062] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0063] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0064] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0065] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A method for detecting and locating crack damage in concrete slabs, characterized in that, include: The guided wave signals collected by the ring sensor array arranged on the surface of the concrete slab are acquired, including non-destructive signals and lossy signals. The non-destructive signals are the signals received by the receiver after the exciter emits Lamb waves in the healthy concrete slab, and the lossy signals are the signals received by the receiver after the exciter emits Lamb waves in the cracked concrete slab. Based on the lossless and lossy signals, the scattered signal of each detection path is calculated, and the envelope of the scattered signal is extracted to obtain the flight time of the scattered wave. Based on the flight time of the scattered wave, calculate the flight time delay factor of each pixel for each detection path; Based on the time-of-flight delay factor, a probabilistic damage spatial distribution function is constructed, and combined with the signal difference characteristic factor, the damage probability of each pixel for each detection path is calculated. The final damage probability distribution of a pixel is obtained by multiplying the damage probabilities of each pixel under different detection paths in pairs and then summing them. Damage imaging is performed based on the final damage probability distribution, and the location information of the crack damage is output.

2. The method as described in claim 1, characterized in that, The acquisition of the guided wave signal includes: The sensors in the ring sensor array are used sequentially as exciters to emit Lamb wave signals, and the remaining sensors are used as receivers to receive the signals. Collect non-destructive signals in a healthy state and destructive signals in a state containing crack damage; The sensor array consists of multiple piezoelectric sensors evenly arranged on a ring array.

3. The method as described in claim 1, characterized in that, The calculation of the flight time of the scattered wave includes: subtracting the response signal in the damaged structure from the baseline signal in the healthy structure to obtain the scattered signal; Perform a Hilbert transform on the scattered signal to extract its envelope; The time corresponding to the first peak point of the envelope is taken as the flight time of the scattered wave.

4. The method as described in claim 1, characterized in that, The formula for calculating the flight time delay factor is as follows: ； in, This represents the theoretical flight time for the pixel corresponding to the current detection path. This represents the flight time of the scattered wave along the current detection path.

5. The method as described in claim 1, characterized in that, The formula for calculating the signal difference characteristic factor is as follows: ； in, For the first The detection path contains a non-destructive signal. For the first The lossy signal of the detection path, where Cov represents the covariance and σ represents the standard deviation.

6. The method as described in claim 1, characterized in that, The formula for calculating the final damage probability distribution is: ； in, For pixels For the The probability value of damage along the detection path. This represents the total number of detection paths.

7. A concrete slab crack damage detection and positioning system, characterized in that, include: The sensor array module is used to arrange a ring sensor array on the surface of a concrete slab to excite Lamb wave signals and receive the propagated signals. The signal acquisition module is used to control the excitation and signal acquisition of the sensor array to obtain lossless signals and lossy signals; the lossless signal is the signal received by the receiver after the exciter emits a Lamb wave in a healthy concrete slab, and the lossy signal is the signal received by the receiver after the exciter emits a Lamb wave in a concrete slab with crack damage. The signal processing module is used to calculate the scattered signal of each detection path based on the lossless signal and the lossy signal, extract the envelope of the scattered signal, and obtain the flight time of the scattered wave; based on the flight time of the scattered wave, calculate the flight time delay factor of each pixel for each detection path; based on the flight time delay factor, construct a probability damage spatial distribution function, and combine it with the signal difference characteristic factor to calculate the damage probability of each pixel for each detection path; multiply the damage probabilities of each pixel under different detection paths pairwise and then sum them to obtain the final damage probability distribution of the pixel. The imaging module is used to perform damage imaging based on the final damage probability distribution and output the location information of the crack damage. The display module is used to display the imaging results of crack damage.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the program, it implements the steps of the concrete slab crack damage detection and location method as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the concrete slab crack damage detection and localization method as described in any one of claims 1 to 6.

10. A computer program product, comprising software code, characterized in that, The program in the software code performs the steps of the concrete slab crack damage detection and location method as described in any one of claims 1 to 6.

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