Concrete damage identifying and positioning method and system based on piezoelectric sensor

Abstract

According to the piezoelectric sensor-based concrete damage identification and positioning method and system provided by the invention, the appearance characteristics of the concrete structure are identified through non-contact detection, so that the piezoelectric sensor arrangement state information of the concrete structure is determined, and the piezoelectric sensors are accurately arranged according to the appearance characteristics of different areas in the concrete structure; it is guaranteed that the concrete structure is comprehensively detected under the condition that few piezoelectric sensors are used; based on signal detection characteristics of a plurality of piezoelectric sensor pairs arranged on the concrete structure, a damage position point in the concrete structure is determined, so that form information of a damage area in the concrete structure is estimated, and accurate positioning of the damage area is realized; and based on the form information of the damage area, the damage change trend is predicted so as to carry out safety early warning notification of the concrete structure and comprehensively predict the evolution of the damage range in the concrete structure, so that damage detection can be continuously carried out on the concrete structure for a long time, and the concrete damage identification and positioning continuity and accuracy are improved.

Description

Technical Field

[0001] The present invention relates to the field of concrete damage detection, and particularly to a method and system for identifying and locating concrete damage based on piezoelectric sensors. Background Art

[0002] As an important material for modern buildings, concrete is widely used in buildings such as bridges and buildings. The shrinkage rate and shrinkage uniformity of concrete are easily affected by factors such as the external environmental temperature and humidity during the pouring process. If the concrete shrinkage rate is too high or the shrinkage is uneven, it will cause uneven stress distribution inside the concrete. When the internal stress of the concrete is in an uneven distribution state for a long time, structural damages such as cracks will be formed inside the concrete. These structural damages will continuously expand in shape, causing irreversible damage to the concrete structure and seriously threatening the safety of the concrete structure. Existing technologies can use means such as X-ray flaw detection to detect the inside of the concrete structure, but the detection coverage of this means is limited, and it is impossible to perform continuous and automated flaw detection on the concrete structure, and it is impossible to dynamically locate and identify the damage evolution state inside the concrete structure, reducing the continuity and accuracy of concrete structure damage detection and identification. Summary of the Invention

[0003] The purpose of the present invention is to provide a method and system for identifying and locating concrete damage based on piezoelectric sensors, which non-contact detects and identifies the external shape characteristics of the concrete structure, thereby determining the piezoelectric sensor arrangement state information of the concrete structure, accurately arranging piezoelectric sensors according to the external shape characteristics of different regions inside the concrete structure, ensuring comprehensive detection of the concrete structure with fewer piezoelectric sensors; based on the signal detection characteristics of several pairs of piezoelectric sensors arranged on the concrete structure, determining the damage position points inside the concrete structure, thereby estimating the morphological information of the damage area inside the concrete structure, realizing precise positioning of the damage area; and then based on the morphological information of the damage area, predicting the damage change trend, thereby sending a safety warning notice for the concrete structure, comprehensively predicting the evolution of the damage range inside the concrete structure, being able to continuously detect the damage of the concrete structure for a long time, and improving the continuity and accuracy of concrete damage identification and location.

[0004] The present invention is realized through the following technical solutions:

[0005] A method for identifying and locating concrete damage based on piezoelectric sensors, comprising:

[0006] Non-contact detecting and identifying the concrete structure to obtain the external shape characteristics of the concrete structure; based on the external shape characteristics, determining the piezoelectric sensor arrangement state information of the concrete structure;

[0007] Based on the signal detection characteristics of several piezoelectric sensors arranged in the concrete structure, determine the damage position points corresponding to each piezoelectric sensor pair detected inside the concrete structure; based on all the damage position points, estimate the morphological information of the damage area inside the concrete structure;

[0008] Based on the morphological information of the damage area, predict the damage change trend inside the concrete structure; based on the damage change trend, issue a safety warning notice for the concrete structure.

[0009] Optionally, perform non-contact detection and identification on the concrete structure to obtain the external shape characteristics of the concrete structure; based on the external shape characteristics, determine the piezoelectric sensor arrangement state information for the concrete structure, including:

[0010] Perform binocular shooting on the concrete structure to obtain the binocular image of the concrete structure; based on the binocular disparity of the binocular image, generate the three-dimensional image of the concrete structure; perform contour recognition on the three-dimensional image to obtain the three-dimensional contour characteristics of the concrete structure; based on the three-dimensional contour characteristics, determine the external shape deformation characteristics of the concrete structure; wherein, the external shape deformation characteristics include the distribution characteristics of the external shape deformation amplitude in the global range of the concrete structure;

[0011] Based on the external shape deformation characteristics, determine all load abnormal sub-regions within the global range of the concrete structure; based on the spatial position and spatial area of the load abnormal sub-regions, determine the piezoelectric sensor arrangement state information for the load abnormal sub-regions; wherein, the piezoelectric sensor arrangement information includes the position and quantity of piezoelectric sensors arranged within the load abnormal sub-regions.

[0012] Optionally, based on the signal detection characteristics of several piezoelectric sensors arranged in the concrete structure, determine the damage position points corresponding to each piezoelectric sensor pair detected inside the concrete structure; based on all the damage position points, estimate the morphological information of the damage area inside the concrete structure, including:

[0013] Obtain the starting time of the excitation signal and the starting time of the scattered signal for each piezoelectric sensor pair arranged in the concrete structure, based on the time difference between the starting time of the excitation signal and the starting time of the scattered signal; based on the transmission azimuth characteristics of the excitation signal of each piezoelectric sensor pair and the time difference, determine the damage position points corresponding to each piezoelectric sensor pair detected inside the concrete structure;

[0014] Based on the position information of all damage location points corresponding to all piezoelectric sensors detected inside the concrete structure, perform boundary fitting estimation on the damage area inside the concrete structure to obtain the morphological information of the damage area inside the concrete structure; wherein, the morphological information of the damage area includes the boundary contour information of the damage area.

[0015] Optionally, based on the morphological information of the damage area, predict the damage change trend inside the concrete structure; based on the damage change trend, conduct safety early warning notification for the concrete structure, including:

[0016] Conduct time-evolution analysis on the boundary contour information of the damage area included in the morphological information of the damage area to predict the change trend of the coverage space range of the damage area inside the concrete structure;

[0017] Based on the change trends of the coverage space ranges of all damage areas, obtain the increase rate of the continuous damage area space range inside the concrete structure within a preset future time; based on the increase rate of the continuous damage area space range, generate and send a safety early warning message for the concrete structure.

[0018] Optionally, considering that the piezoelectric sensor is fixed inside the concrete structure and cannot move, and the structural changes of the concrete structure itself and the changes in the surrounding temperature and humidity will cause deviations in the readings of the piezoelectric sensor, it is necessary to correct the readings of the piezoelectric sensor, specifically including:

[0019] Using the following formula (1), according to the reading result value of the piezoelectric sensor, obtain the damage index of the concrete in the detection area of the piezoelectric sensor,

[0020]

[0021] In the above formula (1), D(t) represents the damage index of the concrete in the detection area of the piezoelectric sensor at time t, and 0 ≤ D ≤ 2; Y(t) represents the piezoelectric admittance value read by the piezoelectric sensor at time t; Y0 represents the piezoelectric admittance value read at a preset reference; α represents the strength of the concrete self-healing effect, and 0 ≤ α ≤ 1. When the self-healing ability of the concrete is stronger, the value of α is larger; β represents the self-healing rate of the concrete; e -βt represents the self-healing effect correction factor, which simulates the damage weakening phenomenon caused by concrete self-healing or microcrack closure in the form of an exponent; γ represents the temperature change rate on the concrete of the damage gain coefficient; represents the temperature change rate on the concrete; ln(1 + ) is introduced to prevent interference from negative temperature change rate values; e represents the natural constant;

[0022] Using the following formula (2), the output drift of the piezoelectric sensor is determined according to the damage index of the concrete in the detection area of the piezoelectric sensor and the humidity change around the piezoelectric sensor.

[0023]

[0024] In the above formula (2), ΔS(t) represents the output drift of the piezoelectric sensor at time t; λ represents the basic aging rate of the piezoelectric sensor; H(t) represents the humidity detection value of the humidity sensor inside the piezoelectric sensor at time t; H ref represents the reference humidity value suitable for the operation of the piezoelectric sensor; μ represents the dynamic sensitivity coefficient of the piezoelectric sensor to the damage of the concrete; represents the second derivative of the piezoelectric admittance value read by the piezoelectric sensor, which is used to characterize the damage mutation of the concrete;

[0025] Using the following formula (3), the calibration mechanism of the piezoelectric sensor is controlled according to the damage index of the concrete in the detection area of the piezoelectric sensor and the output drift of the piezoelectric sensor.

[0026]

[0027] In the above formula (3), C(t) represents the calibration control signal for controlling the piezoelectric sensor; S max represents the preset drift threshold;

[0028] If C(t) = -1, it means that the damage of the concrete in the detection area of the piezoelectric sensor is over-limit and the drift amount exceeds the threshold, and the piezoelectric sensor is automatically restarted and reset;

[0029] If C(t) = 1, dynamic calibration is performed on the piezoelectric sensor, that is, the real-time reading result value of the piezoelectric sensor is subtracted by ΔS(t)×e -vt , where v represents the compensation attenuation coefficient of the piezoelectric sensor;

[0030] If C(t) = 0, the piezoelectric sensor is not calibrated and only the real-time reading result value is recorded.

[0031] A concrete damage identification and location system based on a piezoelectric sensor includes:

[0032] A concrete structure shape recognition module for non-contact detection and recognition of the concrete structure to obtain the shape characteristics of the concrete structure;

[0033] A sensor arrangement state determination module for determining the piezoelectric sensor arrangement state information of the concrete structure based on the shape characteristics;

[0034] The damage location point determination module is used to determine the damage location points corresponding to the detection inside the concrete structure for each pair of piezoelectric sensors based on the signal detection characteristics of a number of piezoelectric sensors arranged on the concrete structure;

[0035] The damage area morphology determination module is used to estimate the damage area morphology information inside the concrete structure based on all the damage location points;

[0036] The damage change trend prediction module is used to predict the damage change trend inside the concrete structure based on the damage area morphology information;

[0037] The early warning notification module is used to conduct safety early warning notifications for the concrete structure based on the damage change trend.

[0038] Optionally, the concrete structure shape recognition module is used to perform non-contact detection and recognition on the concrete structure to obtain the shape characteristics of the concrete structure, including:

[0039] Performing binocular shooting on the concrete structure to obtain the binocular image of the concrete structure; generating a three-dimensional image of the concrete structure based on the binocular disparity of the binocular image; performing contour recognition on the three-dimensional image to obtain the three-dimensional contour characteristics of the concrete structure; determining the shape deformation characteristics of the concrete structure based on the three-dimensional contour characteristics; wherein, the shape deformation characteristics include the distribution characteristics of the shape deformation amplitude in the global range of the concrete structure;

[0040] The sensor arrangement state determination module is used to determine the piezoelectric sensor arrangement state information for the concrete structure based on the shape characteristics, including:

[0041] Determining all load abnormal sub-regions in the global range of the concrete structure based on the shape deformation characteristics; determining the piezoelectric sensor arrangement state information for the load abnormal sub-regions based on the spatial positions and spatial areas of the load abnormal sub-regions; wherein, the piezoelectric sensor arrangement information includes the positions and quantities of piezoelectric sensors arranged in the load abnormal sub-regions.

[0042] Optionally, the damage location point determination module is used to determine the damage location points corresponding to the detection inside the concrete structure for each pair of piezoelectric sensors based on the signal detection characteristics of a number of piezoelectric sensors arranged on the concrete structure, including:

[0043] Obtain the starting time of the excitation signal and the starting time of the scattered signal for each pair of piezoelectric sensors arranged in the concrete structure, based on the time difference between the starting time of the excitation signal and the starting time of the scattered signal; based on the transmission azimuth characteristics of the excitation signal of each pair of piezoelectric sensors and the time difference, determine the damage location points corresponding to the detection inside the concrete structure for each pair of piezoelectric sensors;

[0044] The damage area morphology determination module is used to estimate the damage area morphology information inside the concrete structure based on all the damage location points, including:

[0045] Based on the position information of all the damage location points corresponding to the detection inside the concrete structure by all pairs of piezoelectric sensors, perform boundary fitting estimation on the damage area inside the concrete structure to obtain the damage area morphology information inside the concrete structure; wherein, the damage area morphology information includes damage area boundary contour information.

[0046] Optionally, the damage change trend prediction module is used to predict the damage change trend inside the concrete structure based on the damage area morphology information, including:

[0047] Perform time-evolution analysis on the damage area boundary contour information included in the damage area morphology information to predict the change trend of the covered space range of the damage area inside the concrete structure;

[0048] The early warning notification module is used to perform safety early warning notification for the concrete structure based on the damage change trend, including:

[0049] Based on the change trend of the covered space range of all damage areas, obtain the continuous damage area space range increase rate inside the concrete structure within a preset future time; based on the continuous damage area space range increase rate, generate and send a safety early warning message for the concrete structure.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The concrete damage identification and location method and system based on piezoelectric sensors provided by this application non - contact detect and identify the external shape characteristics of the concrete structure, so as to determine the layout state information of the piezoelectric sensors of the concrete structure, accurately layout the piezoelectric sensors according to the external shape characteristics of different regions inside the concrete structure, and ensure the comprehensive detection of the concrete structure with fewer piezoelectric sensors; based on the signal detection characteristics of several pairs of piezoelectric sensors arranged in the concrete structure, determine the damage position points inside the concrete structure, so as to estimate the morphological information of the damage area inside the concrete structure and achieve the precise location of the damage area; then based on the morphological information of the damage area, predict the damage change trend, so as to issue a safety warning notice for the concrete structure, comprehensively predict the evolution of the damage range inside the concrete structure, be able to continuously detect the damage of the concrete structure for a long time, and improve the continuity and accuracy of concrete damage identification and location. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0053] Figure 1 It is a schematic flow chart of the concrete damage identification and location method based on piezoelectric sensors provided by the present invention.

[0054] Figure 2 It is a schematic principle diagram of using piezoelectric sensor pairs to detect damage position points in the concrete damage identification and location method based on piezoelectric sensors provided by the present invention.

[0055] Figure 3 It is a schematic principle diagram of using multiple pairs of piezoelectric sensors to determine the editing contour of the damage area in the concrete damage identification and location method based on piezoelectric sensors provided by the present invention.

[0056] Figure 4 It is a schematic structural diagram of the concrete damage identification and location system based on piezoelectric sensors provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings. It can be understood that the specific embodiments described herein are only for explaining the present application and not for limiting the present application. Additionally, it should be noted that for the convenience of description, only the parts related to the present application rather than all the structures are shown in the drawings. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present application.

[0058] The terms "including" and "having" and any variations thereof in the present application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0059] Referring to the embodiments herein means that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears at various positions in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0060] Please refer to Figure 1 As shown, a concrete damage identification and location method based on piezoelectric sensors provided by an embodiment of the present application. The concrete damage identification and location method based on piezoelectric sensors includes:

[0061] Performing non-contact detection and identification on the concrete structure to obtain the external shape characteristics of the concrete structure; based on the external shape characteristics, determining the piezoelectric sensor arrangement state information of the concrete structure;

[0062] Based on the signal detection characteristics of several piezoelectric sensors arranged on the concrete structure, determining the damage location points corresponding to each piezoelectric sensor pair detected inside the concrete structure; based on all the damage location points, estimating the damage area shape information inside the concrete structure;

[0063] Based on the damage area shape information, predicting the damage change trend inside the concrete structure; based on the damage change trend, issuing a safety warning notice for the concrete structure.

[0064] Beneficial effects of the above embodiments. The method for identifying and locating concrete damage based on piezoelectric sensors non-contact detects and identifies the external shape features of the concrete structure, thereby determining the layout state information of the piezoelectric sensors of the concrete structure. The piezoelectric sensors are accurately arranged according to the external shape features of different regions inside the concrete structure, ensuring comprehensive detection of the concrete structure with fewer piezoelectric sensors; based on the signal detection features of several pairs of piezoelectric sensors arranged in the concrete structure, the damage location points inside the concrete structure are determined, and based on this, the morphological information of the damage area inside the concrete structure is estimated to achieve precise positioning of the damage area; then, based on the morphological information of the damage area, the damage change trend is predicted, and based on this, a safety warning notice for the concrete structure is issued, comprehensively predicting the evolution of the damage range inside the concrete structure, and being able to continuously detect the damage of the concrete structure for a long time, improving the continuity and accuracy of concrete damage identification and location.

[0065] In another embodiment, non-contact detection and identification of the concrete structure is performed to obtain the external shape features of the concrete structure; based on the external shape features, the layout state information of the piezoelectric sensors for the concrete structure is determined, including:

[0066] Binocular shooting of the concrete structure is performed to obtain the binocular image of the concrete structure; based on the binocular disparity of the binocular image, a three-dimensional image of the concrete structure is generated; contour recognition is performed on the three-dimensional image to obtain the three-dimensional contour features of the concrete structure; based on the three-dimensional contour features, the external shape deformation features of the concrete structure are determined; wherein, the external shape deformation features include the external shape deformation amplitude distribution features in the global range of the concrete structure.

[0067] Based on the external shape deformation features, all load abnormal sub-regions within the global range of the concrete structure are determined; based on the spatial position and spatial area of the load abnormal sub-regions, the layout state information of the piezoelectric sensors for the load abnormal sub-regions is determined; wherein, the piezoelectric sensor layout information includes the positions and quantities of the piezoelectric sensors arranged within the load abnormal sub-regions.

[0068] Beneficial effects of the above embodiments: During the pouring process of the concrete structure, due to the influence of the external environmental temperature, the internal solidification shrinkage is inconsistent, resulting in uneven internal stress distribution. This uneven internal stress distribution will cause the mechanical strength of the concrete in a certain direction to be low, and it is easy to generate damages such as cracks. The cracks inside the concrete structure do not form during the pouring process. Usually, when the concrete structure bears a large weight load, it is formed under the action of external loads, especially uneven load effects. When the weight of the load borne by a certain area of the concrete structure itself is greater, the unevenness of the stress distribution inside the concrete structure in the corresponding area will be aggravated, resulting in a large deformation of the concrete structure in the corresponding area, thereby increasing the probability of generating damages such as cracks in the corresponding area inside the concrete structure. Through the above analysis, it can be seen that the quantity and scope of damages such as cracks generated inside the concrete structure are related to the load state of the concrete structure itself. And when damages such as cracks are generated inside the concrete structure under the action of external loads, local deformation will occur in the concrete structure. Therefore, by observing the shape deformation state of the concrete structure, it is possible to estimate the abnormal load sub-areas inside the concrete structure, and it is also possible to determine that the damages such as cracks inside the concrete structure are roughly distributed inside or in the adjacent range of the abnormal load sub-areas, which is convenient for subsequently determining the position and quantity of piezoelectric sensors arranged inside the concrete structure based on the abnormal load sub-areas, so as to conduct a comprehensive and accurate piezoelectric detection of the concrete structure with fewer piezoelectric sensors, improve the detection accuracy of the concrete structure, and reduce the workload of arranging piezoelectric sensors for the concrete structure.

[0069] Specifically, in order to accurately and comprehensively identify the shape deformation of a concrete structure, binocular vision recognition is first performed on the concrete structure to obtain the three-dimensional contour features of the concrete structure. The three-dimensional contour features can be, but are not limited to, the three-dimensional contour shape and three-dimensional contour position of the outer surface of the concrete structure. Time evolution analysis is performed on the three-dimensional contour features to obtain the shape deformation amplitude distribution features in the global range of the concrete structure. The shape deformation amplitude distribution features can be, but are not limited to, the shape deformation amplitude values of all sub-regions under the global range of the concrete structure. The larger the shape deformation amplitude value of a certain sub-region under the global range of the concrete structure, the more uneven the stress distribution within the above-mentioned sub-region of the concrete structure, and it is easier for cracks and other damages to form within the above-mentioned sub-region or the number of existing cracks and other damages within the above-mentioned sub-region is also larger. That is, the above-mentioned sub-region corresponds to the load abnormal sub-region of the concrete structure. By comparing the shape deformation amplitude values of all sub-regions under the global range of the concrete structure with a threshold, if the shape deformation amplitude value is greater than the preset amplitude threshold, the corresponding sub-region is determined as the load abnormal sub-region. Then, based on the spatial position and spatial area of the load abnormal sub-region, the position and number of piezoelectric sensors arranged in the load abnormal sub-region are determined. Generally speaking, the piezoelectric sensors can be evenly arranged inside and / or on the boundary of the load abnormal sub-region. The larger the area of the load abnormal sub-region, the more piezoelectric sensors are arranged in the load abnormal sub-region. Among them, each piezoelectric sensor includes both an excitation signal generation component and an excitation signal reception component. The excitation signal generation component is used to emit excitation signals such as sound waves to the concrete structure, and the excitation signal reception component is used to receive the excitation signals such as sound waves transmitted inside the concrete structure. When the sound wave reaches the excitation signal reception component, it will generate an impact pressure on the excitation signal reception component, and the excitation signal reception component will convert the impact pressure into a corresponding voltage signal. Further, different piezoelectric sensors are arranged at different positions inside the concrete structure. The excitation signal generation component of one piezoelectric sensor emits sound waves into the concrete structure. These sound waves are transmitted inside the concrete structure. When the sound waves reach the damage position point inside the concrete structure, the sound waves will be scattered due to the damage structure at the damage position point. The scattered sound waves will change the transmission direction and be received by the excitation signal reception component of another piezoelectric sensor to generate a corresponding voltage signal. The position corresponding to the damage position point can be calculated and determined by analyzing the voltage signal later. The detection process of the above-mentioned damage position point will be explained in detail later.

[0070] In another embodiment, based on the signal detection features of several piezoelectric sensors arranged on the concrete structure, the damage position points corresponding to each piezoelectric sensor detected inside the concrete structure are determined. Based on all the damage position points, the morphological information of the damage area inside the concrete structure is estimated, including:

[0071] Obtain the start time of the excitation signal and the start time of the scattered signal for each piezoelectric sensor pair arranged in the concrete structure, based on the time difference between the start time of the excitation signal and the start time of the scattered signal; based on the transmission azimuth characteristics of the excitation signal and this time difference of each piezoelectric sensor pair, determine the damage location points corresponding to the detection inside the concrete structure for each piezoelectric sensor pair;

[0072] Based on the position information of all the damage location points corresponding to the detection inside the concrete structure for all the piezoelectric sensor pairs, perform boundary fitting estimation on the damage area inside the concrete structure to obtain the morphological information of the damage area inside the concrete structure; wherein, the morphological information of the damage area includes the boundary contour information of the damage area.

[0073] The beneficial effects of the above embodiments Figure 2 is a schematic diagram of the principle for detecting damage location points using piezoelectric sensor pairs. After determining the positions and quantities of the piezoelectric sensors arranged in the load abnormal sub-region, piezoelectric sensors will be correspondingly arranged in the load abnormal sub-region of the concrete structure. Generally, all the arranged piezoelectric sensors are adjacent to the damage area. When the excitation signal generating component of one piezoelectric sensor (such as the left piezoelectric sensor) emits an excitation signal outward, the excitation signal will be transmitted to a damage location point on the boundary of the damage area. The damage location point will scatter the excitation signal to form a scattered signal, and the scattered signal will be transmitted along the corresponding direction and reach the excitation signal receiving component of another piezoelectric sensor (such as the right piezoelectric sensor). In this way, the excitation signal receiving component can convert the received scattered signal into a voltage signal, and the location of the damage location point can be determined by analyzing the voltage signal. Specifically, the signal transmission distance D corresponding to the process of the excitation signal emitted by the left piezoelectric sensor being converted into a scattered signal and transmitted to the right piezoelectric sensor is equal to the sum of the distance D1 between the left piezoelectric sensor and the damage location point and the distance D2 between the right piezoelectric sensor and the damage location point, that is, D = D1 + D2. In addition, in the concrete structure, both the excitation signal and the scattered signal are transmitted in the form of stress waves, and the transmission speed v of the stress wave in the concrete structure g is a constant, so the signal transmission distance D can be expressed as D = D1 + D2 = v g*Δt, where Δt is the transmission time of the stress wave inside the concrete structure. When the relative positions of the piezoelectric sensors on the left and right sides and the damage location point are determined, the transmission time Δt is also a constant. In this way, it can be determined that the signal transmission distance D is also a constant. The piezoelectric sensors on the left and right sides together form a pair of piezoelectric sensors. When the sum of the distance D1 from the piezoelectric sensor on the left side to the damage location point and the distance D2 from the piezoelectric sensor on the right side to the damage location point is a constant, based on the well-known common sense in the field of geometry, the damage location point is located on an ellipse with the positions of the piezoelectric sensors on the left and right sides as the foci, and the length of the major axis of the ellipse is D. Since the transmission speed v of the stress wave in the concrete structure g is a constant, the signal transmission distance D is the shortest distance for the excitation signal to be emitted from the piezoelectric sensor on the left side and scattered through the damage location point and then transmitted to the piezoelectric sensor on the right side. That is, the piezoelectric sensor on the right side is the first to receive the scattered signal formed after the excitation signal is scattered through the damage location point compared with piezoelectric sensors at other positions. According to the above analysis, by determining the time point t1 when the excitation signal is emitted from the piezoelectric sensor on the left side (i.e., the starting time of the excitation signal) and the time point t2 when the scattered signal is received by the piezoelectric sensor on the right side (i.e., the starting time of the scattered signal), the transmission time Δt of the stress wave inside the concrete structure can be determined (the time difference between the starting time of the excitation signal and the starting time of the scattered signal), that is, Δt = t2 - t1. Through the above analysis, first determine the time difference between the starting time of the excitation signal and the starting time of the scattered signal, and combine the excitation signal transmission azimuth characteristics (such as the excitation signal transmission azimuth angle) of each pair of piezoelectric sensors and the positions of the two piezoelectric sensors subordinate to each pair of piezoelectric sensors to determine the location of the damage location point corresponding to the detection inside the concrete structure for each pair of piezoelectric sensors.

[0074] Please refer to Figure 3 Fig. is a schematic diagram of the principle for using multiple pairs of piezoelectric sensors to determine the editing contour of the damage area. Through the above process, it can be seen that a damage location point on the boundary of the damage area can be determined by any pair of piezoelectric sensors composed of two piezoelectric sensors. The damage location point corresponds to the boundary contour point of the damage area. As long as the number of damage location points determined through the above process is sufficient, the boundary contour of the damage area can be determined. Therefore, based on the position information of all the damage location points corresponding to the detection inside the concrete structure for all pairs of piezoelectric sensors, boundary fitting estimation is performed on the damage area inside the concrete structure to obtain the morphological information of the damage area inside the concrete structure, thereby obtaining the boundary contour information of the damage area inside the concrete structure, accurately identifying and locating the range of the damage area inside the concrete structure, and providing a reliable basis for subsequent prediction of the change in the size of the coverage space range of the damage area inside the concrete structure.

[0075] In another embodiment, based on the morphological information of the damaged area, the damage change trend inside the concrete structure is predicted; based on the damage change trend, a safety warning notice for the concrete structure is carried out, including:

[0076] Perform a time-evolution analysis on the damaged area boundary contour information included in the morphological information of the damaged area to predict the change trend of the coverage space range of the damaged area inside the concrete structure;

[0077] Based on the change trends of the coverage space ranges of all damaged areas, obtain the increase rate of the continuous damaged area space range inside the concrete structure within a preset future time; based on the increase rate of the continuous damaged area space range, generate and send a safety warning message for the concrete structure.

[0078] The beneficial effects of the above embodiments are as follows. When there is a damaged area inside the concrete structure, the damaged area will gradually expand. As the space range of the damaged area expands, two originally unconnected damaged areas inside the concrete structure will become connected. The larger the space range of the connected damaged areas inside the concrete structure, the faster the mechanical strength degradation rate of the concrete structure. When the proportion of the space range of the connected damaged areas inside the concrete structure exceeds a preset proportion threshold, the concrete structure will have structural problems such as collapse. In order to accurately predict the change of the damage degree inside the concrete structure, perform a time-evolution analysis on the damaged area boundary contour information included in the morphological information of the damaged area to predict the change trend of the coverage space range of the damaged area inside the concrete structure, that is, predict the change trend of the coverage space range size of each damaged area inside the concrete structure. Then, based on the change trends of the coverage space ranges of all damaged areas, obtain the increase rate of the continuous damaged area space range inside the concrete structure within a preset future time, that is, the increase rate of the size of the space range of the damaged areas in a connected state within a preset future time; compare the increase rate of the continuous damaged area space range with a preset increase rate threshold. If the increase rate of the continuous damaged area space range exceeds the preset increase rate threshold, generate and send a safety warning message for the concrete structure in time to warn of the structural stability and safety of the concrete structure.

[0079] In another embodiment, considering that the piezoelectric sensor is fixed inside the concrete structure and cannot move, and the structural changes of the concrete structure itself and the changes in the surrounding temperature and humidity will cause deviations in the readings of the piezoelectric sensor, it is necessary to correct the readings of the piezoelectric sensor, specifically including:

[0080] Using the following formula (1), according to the reading result value of the piezoelectric sensor, obtain the damage index of the concrete in the detection area of the piezoelectric sensor,

[0081]

[0082] In the above formula (1), D(t) represents the damage index of the concrete in the detection area of the piezoelectric sensor at time t, and 0 ≤ D ≤ 2; Y(t) represents the piezoelectric admittance value read by the piezoelectric sensor at time t; Y0 represents the piezoelectric admittance value read based on a preset reference; α represents the strength of the concrete self-healing effect, and 0 ≤ α ≤ 1. The greater the self-healing ability of the concrete, the larger the value of α; β represents the self-healing rate of the concrete; e -βt represents the self-healing effect correction factor, which simulates the damage weakening phenomenon caused by concrete self-healing or microcrack closure in the form of an exponent; γ represents the temperature change rate on the concrete of the damage gain coefficient; represents the temperature change rate on the concrete; ln(1 + ) is introduced to prevent the negative value of the temperature change rate from interfering; e represents the natural constant;

[0083] Using the following formula (2), according to the damage index of the concrete in the detection area of the piezoelectric sensor and the humidity change around the piezoelectric sensor, the output drift of the piezoelectric sensor is determined.

[0084]

[0085] In the above formula (2), ΔS(t) represents the output drift of the piezoelectric sensor at time t; λ represents the basic aging rate of the piezoelectric sensor; H(t) represents the humidity detection value of the humidity sensor inside the piezoelectric sensor at time t; H ref represents the reference humidity value for the proper operation of the piezoelectric sensor; μ represents the dynamic sensitivity coefficient of the piezoelectric sensor to the damage of the concrete; represents the second derivative of the piezoelectric admittance value read by the piezoelectric sensor, which is used to characterize the damage mutation of the concrete;

[0086] Using the following formula (3), according to the damage index of the concrete in the detection area of the piezoelectric sensor and the output drift of the piezoelectric sensor, the calibration mechanism of the piezoelectric sensor is controlled.

[0087]

[0088] In the above formula (3), C(t) represents the calibration control signal for controlling the piezoelectric sensor; S max represents the preset drift threshold;

[0089] If C(t) = -1, it means that the damage of the concrete in the detection area of the piezoelectric sensor exceeds the limit and the drift amount exceeds the threshold, and the piezoelectric sensor is automatically restarted and reset;

[0090] If C(t) = 1, dynamic calibration of the piezoelectric sensor is performed, that is, the real-time reading result value of the piezoelectric sensor is subtracted by ΔS(t) × e -vt , where v represents the compensation attenuation coefficient of the piezoelectric sensor;

[0091] If C(t) = 0, the piezoelectric sensor is not calibrated and only the real-time reading result value is recorded.

[0092] The beneficial effects of the above embodiments are as follows. Using the above formula (1), based on the reading result value of the piezoelectric sensor, the damage index of the concrete in the detection area of the piezoelectric sensor is obtained. By jointly modeling the piezoelectric admittance attenuation (where the piezoelectric admittance attenuation is caused by cracks) and the temperature change rate (i.e., thermal expansion and contraction exacerbate damage), it is closer to the actual working conditions of the concrete. The introduction of the exponential term e -βt quantifies the weakening of damage by concrete self-healing and is more accurate than traditional static damage models. Then, using the above formula (2), based on the damage index of the concrete in the detection area of the piezoelectric sensor and the humidity change around the piezoelectric sensor, the output drift of the piezoelectric sensor is determined. By decomposing the drift into a linear term of "aging + humidity" and a non-linear term of "damage dynamics", it is convenient for targeted calibration. And by introducing the second derivative of admittance to capture the sudden expansion event of concrete cracks, the sensor can be calibrated more accurately. Then, using the above formula (3), based on the damage index of the concrete in the detection area of the piezoelectric sensor and the output drift of the piezoelectric sensor, the calibration mechanism of the piezoelectric sensor is controlled. Considering that the calibration trigger condition depends on both the damage index and the drift, environmental interference misjudgment is avoided, and the compensation amount e -vt is added during compensation correction to balance short-term fluctuations and long-term trends.

[0093] Please refer to Figure 4 shown in the figure. A concrete damage identification and location system based on a piezoelectric sensor provided by an embodiment of the present application. The concrete damage identification and location system based on a piezoelectric sensor includes:

[0094] A concrete structure shape recognition module for non-contact detection and recognition of the concrete structure to obtain the shape characteristics of the concrete structure;

[0095] A sensor layout state determination module for determining the piezoelectric sensor layout state information of the concrete structure based on the shape characteristics;

[0096] A damage location point determination module for determining the damage location points corresponding to the internal detection of each piezoelectric sensor pair in the concrete structure based on the signal detection characteristics of a plurality of piezoelectric sensors arranged on the concrete structure;

[0097] A damage area shape determination module for estimating the damage area shape information inside the concrete structure based on all damage location points;

[0098] The damage trend prediction module is used to predict the damage change trend inside the concrete structure based on the morphological information of the damaged area;

[0099] The early warning notification module is used to perform safety early warning notification of the concrete structure based on the damage change trend.

[0100] The beneficial effects of the above embodiments are as follows: The concrete damage identification and location system based on piezoelectric sensors non-contact detects and identifies the external shape characteristics of the concrete structure, thereby determining the layout state information of the piezoelectric sensors of the concrete structure. The piezoelectric sensors are accurately arranged according to the external shape characteristics of different regions inside the concrete structure, ensuring comprehensive detection of the concrete structure with fewer piezoelectric sensors; Based on the signal detection characteristics of several pairs of piezoelectric sensors arranged in the concrete structure, the damage position points inside the concrete structure are determined, and the morphological information of the damaged area inside the concrete structure is estimated, realizing the precise location of the damaged area; Then, based on the morphological information of the damaged area, the damage change trend is predicted, and the safety early warning notification of the concrete structure is carried out, comprehensively predicting the evolution of the damage range inside the concrete structure, and being able to continuously detect the damage of the concrete structure for a long time, improving the continuity and accuracy of concrete damage identification and location.

[0101] In another embodiment, the concrete structure shape recognition module is used to non-contact detect and identify the concrete structure to obtain the external shape characteristics of the concrete structure, including:

[0102] Perform binocular shooting on the concrete structure to obtain the binocular image of the concrete structure; Generate the three-dimensional image of the concrete structure based on the binocular disparity of the binocular image; Perform contour recognition on the three-dimensional image to obtain the three-dimensional contour characteristics of the concrete structure; Determine the external shape deformation characteristics of the concrete structure based on the three-dimensional contour characteristics; Among them, the external shape deformation characteristics include the distribution characteristics of the external shape deformation amplitude in the global range of the concrete structure;

[0103] The sensor layout state determination module is used to determine the layout state information of the piezoelectric sensors for the concrete structure based on the external shape characteristics, including:

[0104] Determine all load abnormal sub-regions in the global range of the concrete structure based on the external shape deformation characteristics; Determine the layout state information of the piezoelectric sensors for the load abnormal sub-regions based on the spatial position and spatial area of the load abnormal sub-regions; Among them, the piezoelectric sensor layout information includes the position and quantity of piezoelectric sensors arranged in the load abnormal sub-regions.

[0105] Beneficial effects of the above embodiments: During the pouring process of a concrete structure, due to the influence of the external environmental temperature, the internal solidification shrinkage of the concrete structure is inconsistent with itself, resulting in uneven internal stress distribution. This uneven internal stress distribution will cause the mechanical strength of the concrete in a certain direction to be low, and it is easy to generate damages such as cracks. The cracks inside the concrete structure do not form during the pouring process. Usually, when the concrete structure bears a large weight load, it is formed under the action of external loads, especially uneven load effects. When the weight of the load borne by a certain area of the concrete structure itself is greater, the unevenness of the stress distribution inside the concrete structure in the corresponding area will be aggravated, resulting in a large deformation of the concrete structure in the corresponding area, thereby increasing the probability of generating damages such as cracks in the corresponding area inside the concrete structure. Through the above analysis, it can be seen that the quantity and scope of damages such as cracks generated inside the concrete structure are related to the load state of the concrete structure itself. And when damages such as cracks are generated inside the concrete structure under the action of external loads, the local area of the concrete structure will deform. Therefore, by observing the shape deformation state of the concrete structure, the abnormal load sub-areas inside the concrete structure can be estimated, and it can also be determined that the damages such as cracks inside the concrete structure are roughly distributed inside or in the adjacent range of the abnormal load sub-areas, which is convenient for subsequently determining the position and quantity of piezoelectric sensors arranged inside the concrete structure based on the abnormal load sub-areas, so as to conduct a comprehensive and accurate piezoelectric detection of the concrete structure with fewer piezoelectric sensors, improve the detection accuracy of the concrete structure, and reduce the workload of arranging piezoelectric sensors on the concrete structure.

[0106] Specifically, in order to accurately and comprehensively identify the shape deformation of a concrete structure, binocular vision recognition is first performed on the concrete structure to obtain the three-dimensional contour features of the concrete structure. The three-dimensional contour features can be, but are not limited to, the three-dimensional contour shape and three-dimensional contour position of the outer surface of the concrete structure. Time evolution analysis is performed on the three-dimensional contour features to obtain the shape deformation amplitude distribution features in the global range of the concrete structure. The shape deformation amplitude distribution features can be, but are not limited to, the shape deformation amplitude values of all sub-regions under the global range of the concrete structure. The larger the shape deformation amplitude value of a certain sub-region under the global range of the concrete structure, the more uneven the stress distribution within the above-mentioned sub-region of the concrete structure, and it is easier for cracks and other damages to form within the above-mentioned sub-region or the number of cracks and other damages already formed within the above-mentioned sub-region is also larger, that is, the above-mentioned sub-region corresponds to the load abnormal sub-region of the concrete structure. By comparing the shape deformation amplitude values of all sub-regions under the global range of the concrete structure with a threshold, if the shape deformation amplitude value is greater than the preset amplitude threshold, the corresponding sub-region is determined as the load abnormal sub-region. Then, based on the spatial position and spatial area of the load abnormal sub-region, the position and number of piezoelectric sensors arranged in the load abnormal sub-region are determined. Generally speaking, the piezoelectric sensors can be evenly arranged inside and / or on the boundary of the load abnormal sub-region. The larger the area of the load abnormal sub-region, the more piezoelectric sensors are arranged in the load abnormal sub-region. Among them, each piezoelectric sensor includes both an excitation signal generation component and an excitation signal receiving component. The excitation signal generation component is used to emit excitation signals such as sound waves to the concrete structure, and the excitation signal receiving component is used to receive the excitation signals such as sound waves transmitted inside the concrete structure. When the sound wave reaches the excitation signal receiving component, it will generate an impact pressure on the excitation signal receiving component, and the excitation signal receiving component will convert the impact pressure into a corresponding voltage signal. Further, different piezoelectric sensors are arranged at different positions inside the concrete structure. The excitation signal generation component of one piezoelectric sensor emits sound waves into the concrete structure. These sound waves are transmitted inside the concrete structure. When the sound waves reach the damage position point inside the concrete structure, the sound waves will be scattered due to the damage structure at the damage position point. The scattered sound waves will change the transmission direction and be received by the excitation signal receiving component of another piezoelectric sensor to generate a corresponding voltage signal. The position corresponding to the damage position point can be calculated and determined by analyzing the voltage signal subsequently. The detection process of the above-mentioned damage position point will be explained in detail later.

[0107] In another embodiment, the damage position point determination module is configured to determine the damage position point corresponding to each piezoelectric sensor detected inside the concrete structure based on the signal detection features of a plurality of piezoelectric sensors arranged on the concrete structure, including:

[0108] Obtain the starting time of the excitation signal and the starting time of the scattered signal for each pair of piezoelectric sensors arranged in the concrete structure, based on the time difference between the starting time of the excitation signal and the starting time of the scattered signal; based on the transmission azimuth feature of the excitation signal and the time difference for each pair of piezoelectric sensors, determine the damage location points corresponding to the detection inside the concrete structure for each pair of piezoelectric sensors.

[0109] The damage area shape determination module is used to estimate the damage area shape information inside the concrete structure based on all the damage location points, including:

[0110] Based on the position information of all the damage location points corresponding to the detection inside the concrete structure for all pairs of piezoelectric sensors, perform boundary fitting estimation on the damage area inside the concrete structure to obtain the damage area shape information inside the concrete structure; wherein, the damage area shape information includes the boundary contour information of the damage area.

[0111] The beneficial effects of the above embodiments Figure 2 is a schematic diagram of the principle for detecting damage location points using pairs of piezoelectric sensors. After determining the positions and quantities of the piezoelectric sensors arranged in the load abnormal sub-region, piezoelectric sensors will be correspondingly arranged in the load abnormal sub-region of the concrete structure. Generally, all the arranged piezoelectric sensors are adjacent to the damage area. When the excitation signal generating component of one piezoelectric sensor (such as the left piezoelectric sensor) emits an excitation signal outward, the excitation signal will be transmitted to a damage location point on the boundary of the damage area. The damage location point will scatter the excitation signal to form a scattered signal, and the scattered signal will be transmitted along the corresponding direction and reach the excitation signal receiving component of another piezoelectric sensor (such as the right piezoelectric sensor). In this way, the excitation signal receiving component can convert the received scattered signal into a voltage signal, and the location of the damage location point can be determined by analyzing the voltage signal. Specifically, the signal transmission distance D corresponding to the process of the excitation signal emitted by the left piezoelectric sensor being converted into a scattered signal and transmitted to the right piezoelectric sensor is equal to the sum of the distance D1 between the left piezoelectric sensor and the damage location point and the distance D2 between the right piezoelectric sensor and the damage location point, that is, D = D1 + D2. In addition, both the excitation signal and the scattered signal are transmitted in the form of stress waves in the concrete structure, and the transmission speed v of the stress wave in the concrete structure g is a constant, so the signal transmission distance D can be expressed as D = D1 + D2 = v g*Δt, where Δt is the transmission time of the stress wave inside the concrete structure. When the relative positions of the piezoelectric sensors on the left and right sides and the damage location point are determined, the transmission time Δt is also a constant. In this way, it can be determined that the signal transmission distance D is also a constant, where the piezoelectric sensors on the left and right sides together form a pair of piezoelectric sensors. When the sum of the distance D1 from the piezoelectric sensor on the left side to the damage location point and the distance D2 from the piezoelectric sensor on the right side to the damage location point is a constant, based on the well-known common sense in the field of geometry, the damage location point is located on an ellipse with the positions of the piezoelectric sensors on the left and right sides as the foci, and the length of the major axis of the ellipse is D. Since the transmission speed v of the stress wave in the concrete structure g is a constant, the signal transmission distance D is the shortest distance for the excitation signal to be emitted from the piezoelectric sensor on the left side, scattered through the damage location point, and transmitted to the piezoelectric sensor on the right side. That is, the piezoelectric sensor on the right side is the first to receive the scattered signal formed after the excitation signal is scattered through the damage location point compared to piezoelectric sensors at other positions. According to the above analysis, by determining the time point t1 when the excitation signal is emitted from the piezoelectric sensor on the left side (i.e., the starting time of the excitation signal) and the time point t2 when the scattered signal is received by the piezoelectric sensor on the right side (i.e., the starting time of the scattered signal), the transmission time Δt of the stress wave inside the concrete structure can be determined (the time difference between the starting time of the excitation signal and the starting time of the scattered signal), that is, Δt = t2 - t1. Through the above analysis, first determine the time difference between the starting time of the excitation signal and the starting time of the scattered signal, and combine the excitation signal transmission azimuth characteristics (such as the excitation signal transmission azimuth angle) of each pair of piezoelectric sensors and the positions of the two piezoelectric sensors under each pair of piezoelectric sensors to determine the location of the damage location point corresponding to the detection inside the concrete structure for each pair of piezoelectric sensors.

[0112] Please refer to Figure 3 Figure for the principle of using multiple pairs of piezoelectric sensors to determine the editing contour of the damage area. Through the above process, it can be seen that a damage location point on the boundary of the damage area can be determined by any pair of piezoelectric sensors composed of two piezoelectric sensors. The damage location point corresponds to the boundary contour point of the damage area. As long as the number of damage location points determined through the above process is sufficient, the boundary contour of the damage area can be determined. For this reason, based on the position information of all damage location points corresponding to the detection inside the concrete structure by all pairs of piezoelectric sensors, boundary fitting estimation is performed on the damage area inside the concrete structure to obtain the morphological information of the damage area inside the concrete structure, thereby obtaining the boundary contour information of the damage area inside the concrete structure, accurately identifying and locating the range of the damage area inside the concrete structure, and providing a reliable basis for predicting the change in the size of the coverage space range of the damage area inside the concrete structure in the future.

[0113] In another embodiment, the damage change trend prediction module is used to predict the damage change trend inside the concrete structure based on the damage area morphology information, including:

[0114] Performing a time-evolution analysis on the damage area boundary contour information included in the damage area morphology information to predict the change trend of the covered space range of the damage area inside the concrete structure;

[0115] The early warning notification module is used to perform a safety early warning notification for the concrete structure based on the damage change trend, including:

[0116] Based on the change trend of the covered space range of all damage areas, obtaining the continuous damage area space range increase rate inside the concrete structure within a preset future time; generating and sending a concrete structure safety early warning message based on the continuous damage area space range increase rate.

[0117] The beneficial effects of the above embodiments are as follows: When there is a damage area inside the concrete structure, the damage area will gradually expand. As the space range of the damage area expands, two originally unconnected damage areas inside the concrete structure will become connected. The larger the space range of the connected damage area inside the concrete structure, the faster the mechanical strength degradation speed of the concrete structure. When the proportion of the space range of the connected damage area inside the concrete structure exceeds a preset proportion threshold, the concrete structure will have structural problems such as collapse. To accurately predict the change of the damage degree inside the concrete structure, a time-evolution analysis is performed on the damage area boundary contour information included in the damage area morphology information to predict the change trend of the covered space range of the damage area inside the concrete structure, that is, to predict the change trend of the covered space range size of each damage area inside the concrete structure. Then, based on the change trend of the covered space range of all damage areas, the continuous damage area space range increase rate inside the concrete structure within a preset future time is obtained, that is, the increase rate of the size of the space range of the damage area in a connected state within a preset future time; comparing the continuous damage area space range increase rate with a preset increase rate threshold, if the continuous damage area space range increase rate exceeds the preset increase rate threshold, then generate and send a concrete structure safety early warning message to timely warn of the structural stability and safety of the concrete structure.

[0118] Generally speaking, the piezoelectric sensor-based concrete damage identification and location method and system non-contact detect and identify the external shape characteristics of the concrete structure, so as to determine the layout state information of the piezoelectric sensors of the concrete structure, accurately layout the piezoelectric sensors according to the external shape characteristics of different regions inside the concrete structure, and ensure the comprehensive detection of the concrete structure with fewer piezoelectric sensors; based on the signal detection characteristics of several pairs of piezoelectric sensors arranged in the concrete structure, determine the damage location points inside the concrete structure, so as to estimate the morphological information of the damage area inside the concrete structure and achieve the precise location of the damage area; then based on the morphological information of the damage area, predict the damage change trend, so as to issue a safety warning notice for the concrete structure, comprehensively predict the evolution of the damage range inside the concrete structure, be able to continuously detect the damage of the concrete structure for a long time, and improve the continuity and accuracy of concrete damage identification and location.

[0119] The above is only a specific implementation manner of the present invention, and any improvement made on the premise of the present invention's concept is regarded as the protection scope of the present invention.

Claims

1. A concrete damage identification and positioning method based on a piezoelectric sensor, characterized in that: include: Performing non-contact detection and identification on the concrete structure to obtain the appearance characteristics of the concrete structure; Based on the shape feature, determining arrangement status information of the piezoelectric sensor for the concrete structure; Based on the respective signal detection characteristics of a plurality of piezoelectric sensor pairs arranged on the concrete structure, determining the corresponding damage location point detected by each piezoelectric sensor pair inside the concrete structure; Based on all damage location points, estimating the morphological information of the damaged area inside the concrete structure; Based on the morphological information of the damaged area, predicting the damage change trend inside the concrete structure; Based on the damage variation trend, a concrete structure safety early warning notification is issued.

2. The concrete damage identification and positioning method based on piezoelectric sensor according to claim 1 is characterized in that: Performing non-contact detection and identification on the concrete structure to obtain the appearance characteristics of the concrete structure; Based on the shape feature, determining the arrangement state information of the piezoelectric sensor of the concrete structure includes: Perform binocular photography on the concrete structure to obtain a binocular image of the concrete structure; generate a three-dimensional image of the concrete structure based on the binocular parallax of the binocular image; perform contour recognition on the three-dimensional image to obtain a three-dimensional contour feature of the concrete structure; determine the shape deformation feature of the concrete structure based on the three-dimensional contour feature; wherein the shape deformation feature includes a shape deformation amplitude distribution feature of the global range of the concrete structure; Based on the shape deformation characteristics, all load abnormality sub-areas within the global range of the concrete structure are determined; based on the spatial position and spatial area of ​​the load abnormality sub-area, the piezoelectric sensor layout status information for the load abnormality sub-area is determined; wherein the piezoelectric sensor layout information includes the position and number of piezoelectric sensors arranged in the load abnormality sub-area.

3. The concrete damage identification and positioning method based on piezoelectric sensor according to claim 1 is characterized in that: Based on the respective signal detection characteristics of a plurality of piezoelectric sensor pairs arranged on the concrete structure, determining the corresponding damage location point detected by each piezoelectric sensor pair inside the concrete structure; Based on all the damage location points, the morphological information of the damaged area inside the concrete structure is estimated, including: Acquire the excitation signal onset time and the scattering signal onset time of each piezoelectric sensor pair arranged on the concrete structure, and determine the damage location point corresponding to each piezoelectric sensor pair inside the concrete structure based on the time difference between the excitation signal onset time and the scattering signal onset time; and determine the damage location point corresponding to each piezoelectric sensor pair inside the concrete structure based on the excitation signal transmission azimuth feature of each piezoelectric sensor pair and the time difference. Based on the position information of all corresponding damage location points detected by all piezoelectric sensors inside the concrete structure, boundary fitting estimation is performed on the damaged area inside the concrete structure to obtain morphological information of the damaged area inside the concrete structure; wherein the morphological information of the damaged area includes boundary contour information of the damaged area.

4. The concrete damage identification and positioning method based on piezoelectric sensor according to claim 1 is characterized in that: Based on the morphological information of the damaged area, predicting the damage change trend inside the concrete structure; Based on the damage change trend, a concrete structure safety early warning notification is issued, including: Performing time-evolution analysis on the damaged area boundary contour information included in the damaged area morphology information to predict the coverage space range change trend of the damaged area inside the concrete structure; Based on the coverage spatial range change trend of all damaged areas, the spatial range increase rate of continuous damaged areas inside the concrete structure within a preset time in the future is obtained; based on the spatial range increase rate of continuous damaged areas, a concrete structure safety warning message is generated and sent.

5. The concrete damage identification and positioning method based on piezoelectric sensor according to claim 1, characterized in that: Considering that the piezoelectric sensor is fixed in the concrete structure and cannot move, and the structural changes of the concrete structure itself and the changes in the surrounding temperature and humidity will cause the reading of the piezoelectric sensor to deviate, it is necessary to calibrate the reading of the piezoelectric sensor, specifically including: The damage index of the concrete in the detection area of ​​the piezoelectric sensor is obtained by using the following formula (1) according to the reading result of the piezoelectric sensor: In the above formula (1), D(t) represents the damage index of the concrete in the detection area of ​​the piezoelectric sensor at time t, and 0≤D≤2; Y(t) represents the piezoelectric admittance value read by the piezoelectric sensor at time t; Y0 represents the piezoelectric admittance value read by the preset reference; α represents the strength of the concrete self-healing effect, and 0≤α≤1. The stronger the self-healing ability of the concrete, the larger the value of α; β represents the concrete self-healing rate; e -βt represents the self-healing effect correction factor, which simulates the damage weakening phenomenon caused by concrete self-healing or microcrack closure in the form of an exponential; γ represents the temperature change rate on the concrete The damage gain coefficient of represents the rate of temperature change on concrete; ln(1+) indicates that the logarithm is introduced to prevent interference from negative values ​​of the temperature change rate; e represents a natural constant; The output drift of the piezoelectric sensor is determined by using the following formula (2) according to the damage index of the concrete in the detection area of ​​the piezoelectric sensor and the humidity change around the piezoelectric sensor: In the above formula (2), ΔS(t) represents the output drift of the piezoelectric sensor at time t; λ represents the basic aging rate of the piezoelectric sensor; H(t) represents the humidity detection value of the humidity sensor inside the piezoelectric sensor at time t; H ref represents the reference humidity value at which the piezoelectric sensor is suitable for operation; μ represents the dynamic sensitivity coefficient of the piezoelectric sensor to the damage of the concrete; The second-order derivative of the piezoelectric admittance value read by the piezoelectric sensor is used to characterize the damage mutation of the concrete; The following formula (3) is used to control the calibration mechanism of the piezoelectric sensor according to the damage index of the concrete in the detection area of ​​the piezoelectric sensor and the output drift of the piezoelectric sensor. In the above formula (3), C(t) represents the calibration control signal for controlling the piezoelectric sensor; S max Indicates the preset drift threshold; If C(t)=-1, it means that the damage of concrete in the detection area of ​​the piezoelectric sensor exceeds the limit and the drift exceeds the threshold, and the piezoelectric sensor is automatically restarted and reset; If C(t)=1, the piezoelectric sensor is dynamically calibrated, that is, the real-time reading value of the piezoelectric sensor is subtracted from ΔS(t)×e -vt , v represents the compensation attenuation coefficient of the piezoelectric sensor; If C(t)=0, the piezoelectric sensor is not calibrated and only the real-time reading result is recorded.

6. The concrete damage identification and positioning system based on piezoelectric sensor is characterized by: include: A concrete structure shape recognition module is used to perform non-contact detection and recognition on the concrete structure to obtain the shape characteristics of the concrete structure; A sensor arrangement state determination module, used to determine arrangement state information of the piezoelectric sensor for the concrete structure based on the shape feature; A damage location point determination module, used to determine the damage location point detected by each piezoelectric sensor pair inside the concrete structure based on respective signal detection characteristics of a plurality of piezoelectric sensor pairs arranged on the concrete structure; A damage area morphology determination module, used for estimating the damage area morphology information inside the concrete structure based on all damage location points; A damage change trend prediction module, used to predict the damage change trend inside the concrete structure based on the morphological information of the damaged area; The early warning notification module is used to provide early warning notification of concrete structure safety based on the damage change trend.

7. The concrete damage identification and positioning system based on piezoelectric sensors according to claim 6, characterized in that: The concrete structure appearance recognition module is used to perform non-contact detection and recognition on the concrete structure to obtain the appearance characteristics of the concrete structure, including: Perform binocular photography on the concrete structure to obtain a binocular image of the concrete structure; generate a three-dimensional image of the concrete structure based on the binocular parallax of the binocular image; perform contour recognition on the three-dimensional image to obtain a three-dimensional contour feature of the concrete structure; determine the shape deformation feature of the concrete structure based on the three-dimensional contour feature; wherein the shape deformation feature includes a shape deformation amplitude distribution feature of the global range of the concrete structure; The sensor arrangement state determination module is used to determine the arrangement state information of the piezoelectric sensor of the concrete structure based on the shape feature, including: Based on the shape deformation characteristics, all load abnormality sub-areas within the global range of the concrete structure are determined; based on the spatial position and spatial area of ​​the load abnormality sub-area, the piezoelectric sensor layout status information for the load abnormality sub-area is determined; wherein the piezoelectric sensor layout information includes the position and number of piezoelectric sensors arranged in the load abnormality sub-area.

8. The concrete damage identification and positioning system based on piezoelectric sensors according to claim 6, characterized in that: The damage location point determination module is used to determine the damage location point detected by each piezoelectric sensor pair inside the concrete structure based on the respective signal detection characteristics of the plurality of piezoelectric sensor pairs arranged on the concrete structure, and includes: Acquire the excitation signal onset time and the scattering signal onset time of each piezoelectric sensor pair arranged on the concrete structure, and determine the damage location point corresponding to each piezoelectric sensor pair inside the concrete structure based on the time difference between the excitation signal onset time and the scattering signal onset time; and determine the damage location point corresponding to each piezoelectric sensor pair inside the concrete structure based on the excitation signal transmission azimuth feature of each piezoelectric sensor pair and the time difference. The damage area morphology determination module is used to estimate the damage area morphology information inside the concrete structure based on all damage location points, including: Based on the position information of all corresponding damage location points detected by all piezoelectric sensors inside the concrete structure, boundary fitting estimation is performed on the damaged area inside the concrete structure to obtain morphological information of the damaged area inside the concrete structure; wherein the morphological information of the damaged area includes boundary contour information of the damaged area.

9. The concrete damage identification and positioning system based on piezoelectric sensors according to claim 6, characterized in that: The damage change trend prediction module is used to predict the damage change trend inside the concrete structure based on the damage area morphology information, including: Performing time-evolution analysis on the damaged area boundary contour information included in the damaged area morphology information to predict the coverage space range change trend of the damaged area inside the concrete structure; The early warning notification module is used to perform a safety early warning notification of the concrete structure based on the damage change trend, including: Based on the coverage spatial range change trend of all damaged areas, the spatial range increase rate of continuous damaged areas inside the concrete structure within a preset time in the future is obtained; based on the spatial range increase rate of continuous damaged areas, a concrete structure safety warning message is generated and sent.

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