A multi-field joint detection method for force path change of a deeply bent member

Abstract

The application discloses a kind of multi-field joint detection methods for the force transmission path change of deep bending member, it is related to technical field, for solving the problem of structure local bearing capacity reduction, the uncertainty of force transmission path increases, by laser scanner identification and mark deep bending member crack location, collect crack width, concrete spalling thickness and area, calculate section loss coefficient, and determine the bearing width of compression bar in combination with crack width, after screening target position, analyze crack density index, judge whether to generate path migration signal.After generating signal, strain data is collected using fiber grating sensor, analyze force transmission path characteristics and detect vibration acceleration, fusion both to evaluate path reconstruction index, judge whether force transmission path changes.The method effectively improves the accuracy and response speed of deep bending member monitoring, avoids potential failure, and ensures structure safety.

Description

Technical Field

[0001] This invention relates to the field of data prediction and updating, and more specifically, to a multi-field joint detection method for force transmission path changes in heavily bent components. Background Technology

[0002] Bend members often exhibit significant shear-compression combined effects, non-uniform crack development, and localized concentration of damage zones under complex loads. This makes them prone to significant force transmission path reconstruction. Existing structural health monitoring technologies mostly rely on single-type sensors such as strain gauges, displacement gauges, and accelerometers, or invert the structural state through a limited number of physical quantity acquisition points. They lack the ability to systematically identify the continuous damage process from crack development to cross-sectional degradation to path change.

[0003] The existing technology has the following shortcomings:

[0004] Currently, most crack identification methods rely on manual inspection or image processing. The judgment of changes in structural force transmission path is mostly based on overall deformation characteristics or simplified model deduction, which makes it difficult to provide effective judgment in the early stage of local damage. Especially in the presence of micro-cracks and local concrete spalling, the local bearing capacity of the structure is reduced and the uncertainty of the force transmission path is increased, which seriously affects the accuracy of damage identification and the reliability of structural safety assessment. Therefore, a multi-field joint detection method for force transmission path changes in deeply bent members is proposed.

[0005] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a multi-field joint detection method for force transmission path changes in deeply bent members. This method utilizes a multi-physics field coupling detection mechanism that combines laser scanning identification, cross-sectional degradation assessment, fiber optic strain monitoring, and vibration characteristic analysis to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a multi-field joint detection method for force transmission path variations in deeply bent members, comprising the following steps:

[0008] Step S1: Identify and mark the crack locations of the heavily bent members using a laser scanner, collect the crack width, concrete spalling thickness, and spalling area at the marked locations, and calculate the section loss coefficient using the concrete spalling thickness and spalling area.

[0009] Step S2: Calculate the load-bearing width of the compression member at the marked location by combining the crack width at the marked location with the section loss coefficient. Filter the target locations based on the load-bearing width of the compression member, detect the distance between each target location, analyze the crack density index of the bending member, and determine whether a path migration signal is generated.

[0010] Step S3: After generating the path migration signal, strain data at each target location is collected based on the fiber optic grating sensor. The force transmission path characteristics at the target location are analyzed based on the strain data, and the vibration acceleration at each target location is detected.

[0011] Step S4: After processing the vibration acceleration and force transmission path characteristics of each target, evaluate the path reconstruction index of the bending member, and determine whether the force transmission path has changed based on the path reconstruction index.

[0012] In a preferred embodiment, in step S1, the heavily bent member is scanned by a laser scanner, and the timestamps of laser emission and reception are recorded;

[0013] The distance from the laser scanner to the surface of the deeply bent component is calculated based on the timestamps of laser emission and reception.

[0014] The point cloud coordinates of each point on the surface of the deeply bent member are obtained by calculating the distance from the laser scanner to the surface of the deeply bent member.

[0015] The point cloud coordinates of each point on the surface of the bending member are taken as the target points in sequence, and a spatial neighborhood is constructed with the target points as the center and according to the preset radius. The average Z-axis height of all point cloud coordinates in the spatial neighborhood is calculated.

[0016] The difference between the Z-axis height of the target point and the average Z-axis height of all point cloud coordinate points in the spatial domain is used as the crack feature value.

[0017] In a preferred embodiment, in step S1, the crack feature value is compared with a preset crack feature threshold to determine the crack location:

[0018] If the crack feature value is less than 0 and the absolute value of the crack feature value is greater than the crack feature value threshold, then the target point is determined to be the crack location.

[0019] Conversely, if the target point is not located at the crack, then it is determined that the target point is not the location of the crack.

[0020] Crack locations are determined by filtering candidate crack points through spatial domain analysis, and all the selected candidate crack points are used to form marked locations.

[0021] The distance between each pair of adjacent points is calculated using the point cloud coordinates on both sides of the marked location, and the maximum distance between adjacent points is taken as the crack width at the marked location.

[0022] In a preferred embodiment, in step S2, only the point cloud coordinates of the marked location are retained. shaft and Axis coordinates and projected onto On a plane;

[0023] The convex hull algorithm is used to obtain the bounding wall. The smallest convex hull polygon containing all points on a plane;

[0024] The concrete spalling area at the marked location is calculated using the vertex coordinates of the minimum convex hull polygon.

[0025] According to the marked position The maximum absolute value of the axis and the coordinates of all point cloud points at unmarked locations The absolute value of the difference between the axis mean values ​​is taken as the concrete spalling thickness at the marked location;

[0026] The cross-sectional loss coefficient is calculated by combining the concrete spalling thickness and concrete spalling area at the marked locations.

[0027] In a preferred embodiment, in step S2, the bearing capacity of the compression bar at the marked location is calculated by combining the crack width at the marked location with the section loss coefficient;

[0028] If the load-bearing width of the compression bar at the marked position is greater than the preset load-bearing width threshold, then the marked position is determined to meet the load-bearing width requirement.

[0029] Conversely, if the marking position does not meet the load-bearing width requirements, it is determined that the marking position does not meet the requirements.

[0030] Record the marked position that meets the load-bearing width requirement as the target position;

[0031] The distance between each target location is calculated based on the point cloud coordinates of the target location, and the crack density index is calculated based on the distance between each target location.

[0032] If the crack density index is greater than or equal to the preset crack density index threshold, a path migration signal is generated.

[0033] Conversely, no path migration signal is generated.

[0034] In a preferred embodiment, in step S3, the strain data at the target location includes the peak strain at the target location and the strain amplitude at the target location.

[0035] The center wavelength reflected by the fiber optic grating is recorded by a fiber optic grating sensor at a preset acquisition period.

[0036] Within the acquisition period, the difference between the center wavelength acquired at each acquisition moment and the center wavelength at the first acquisition moment is taken as the change in the center wavelength at the corresponding acquisition moment.

[0037] Calculate the strain value at the target location based on the change in the center wavelength;

[0038] The difference between the maximum and minimum strain values ​​at the target location is divided by 2 to obtain the strain amplitude at the target location.

[0039] In a preferred embodiment, in step S3, the force transmission path characteristics are obtained by weighted calculation of the strain peak value and strain amplitude at the target location.

[0040] Vibration signals at the target location are collected by vibration sensors and converted into electrical signals. The electrical signals are then recorded by a vibration analyzer and converted into vibration acceleration at the target location.

[0041] In a preferred embodiment, in step S4, the path reconstruction index is calculated after normalizing the vibration acceleration and force transmission path characteristics at each target location.

[0042] In a preferred embodiment, in step S4, if the path reconstruction index is greater than or equal to a preset path reconstruction index threshold, the force transmission path changes.

[0043] If the path reconstruction index is less than the preset path reconstruction index threshold, the force transmission path remains unchanged.

[0044] The technical effects and advantages of this invention are as follows:

[0045] This invention identifies and marks the location of cracks in heavily bent structural members using a laser scanner, collects crack width, concrete spalling thickness, and spalling area, calculates the section loss coefficient using the spalling thickness and area, and calculates the bearing width of the compression member by combining the crack width and the section loss coefficient. It then filters target locations and analyzes the crack density index to determine if a path migration signal has been generated. After the path migration signal is generated, it uses a fiber optic grating sensor to collect strain data, analyzes the force transmission path characteristics, and detects vibration acceleration. Through comprehensive processing of vibration acceleration and force transmission path characteristics, it evaluates the path reconstruction index and further determines whether the force transmission path has changed. This effectively improves the accuracy and response speed of monitoring heavily bent structural members, avoids potential faults, ensures structural safety, and enables dynamic tracking and early warning of the component damage evolution process. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating the implementation of a multi-field joint detection method for force transmission path changes in deeply bent components according to the present invention.

[0047] Figure 2 This is a schematic diagram illustrating the steps of a multi-field joint detection method for force transmission path changes in deeply bent members according to the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention identifies and marks the location of cracks in heavily bent structural members using a laser scanner, collects crack width, concrete spalling thickness, and spalling area, calculates the section loss coefficient using the spalling thickness and area, and calculates the bearing width of the compression member by combining the crack width and the section loss coefficient. It then filters target locations and analyzes the crack density index to determine if a path migration signal has been generated. After the path migration signal is generated, it uses a fiber optic grating sensor to collect strain data, analyzes the force transmission path characteristics, and detects vibration acceleration. Through comprehensive processing of vibration acceleration and force transmission path characteristics, it evaluates the path reconstruction index and further determines whether the force transmission path has changed. This effectively improves the accuracy and response speed of monitoring heavily bent structural members, avoids potential faults, and ensures structural safety.

[0050] Example 1: A multi-field joint detection method for force transmission path variations in deeply bent members, such as... Figures 1 to 2 As shown, it includes the following steps:

[0051] Step S1: Identify and mark the crack locations of the heavily bent members using a laser scanner, collect the crack width, concrete spalling thickness, and spalling area at the marked locations, and calculate the section loss coefficient using the concrete spalling thickness and spalling area.

[0052] Step S2: Calculate the load-bearing width of the compression member at the marked location by combining the crack width at the marked location with the section loss coefficient. Filter the target locations based on the load-bearing width of the compression member, detect the distance between each target location, analyze the crack density index of the bending member, and determine whether a path migration signal is generated.

[0053] Step S3: After generating the path migration signal, strain data at each target location is collected based on the fiber optic grating sensor. The force transmission path characteristics at the target location are analyzed based on the strain data, and the vibration acceleration at each target location is detected.

[0054] Step S4: After processing the vibration acceleration and force transmission path characteristics of each target, evaluate the path reconstruction index of the bending member, and determine whether the force transmission path has changed based on the path reconstruction index.

[0055] The specific implementation is as follows:

[0056] In step S1, the heavily bent component is fully scanned by a laser scanner, and the timestamps of each laser emission and reception are recorded by the internal clock unit of the laser scanner.

[0057] The absolute value of the difference between the timestamps of laser emission and reception is divided by 2 to obtain the one-way propagation time. The product of the one-way propagation time and the laser emission speed of the laser scanner is the distance from the laser scanner to the surface of the heavily bent component.

[0058] By combining the pre-set laser scanner installation information and the distance of the laser scanner to the surface of the deeply bent component, the point cloud coordinates of each point on the surface of the deeply bent component are calculated using trigonometric functions.

[0059] It needs to be explained that a laser scanner is a device that uses laser technology to acquire three-dimensional spatial data, used for comprehensive scanning of deeply bent components; the internal clock unit of the laser scanner is responsible for precise time measurement to ensure time synchronization and accuracy during measurement, and is used to record the timestamps of each laser emission and reception; the preset laser scanner installation information refers to the installation position, angle, direction and other installation-related parameters of the laser scanner in the system, which are set by professionals according to the on-site implementation conditions; trigonometric functions are used to describe the relationship between angles and right triangles. The sine function is used to calculate the distance from the laser scanner to the object surface and the vertical scanning angle of the laser scanner to obtain the z-axis coordinate of the object surface. The cosine function is used to calculate the distance from the laser scanner to the object surface, the vertical scanning angle of the laser scanner and the horizontal scanning angle of the millimeter-wave radar to obtain the x-axis and y-axis coordinates of the object surface, forming a point cloud coordinate set of the surface of the deeply bent component.

[0060] The point cloud coordinates of each point on the surface of the bending member are taken as target points in sequence. A spatial neighborhood is constructed with the target points as the center and a preset radius. The average Z-axis height of all point cloud coordinates in the spatial neighborhood is calculated.

[0061] The difference between the Z-axis height value of the target point and the average Z-axis height value of all point cloud coordinate points in the spatial domain is used as the crack feature value;

[0062] Crack eigenvalues ​​refer to the height deviation of a target point relative to its spatial coordinates in the point cloud, reflecting whether the target point has a concave tendency in the Z-axis direction.

[0063] The location of the crack is determined by comparing the crack feature value with a preset crack feature threshold.

[0064] If the crack feature value is less than 0 and the absolute value of the crack feature value is greater than the crack feature value threshold, then the target point is determined to be the crack location.

[0065] Conversely, if the target point is not located at the crack, it is determined that the target point is not the location of the crack.

[0066] Starting from the crack location, a spatial neighborhood is constructed with a preset radius. Crack locations within the spatial neighborhood are selected as candidate crack points. Then, with each candidate crack point as a new starting point, the above spatial neighborhood construction and selection operations are repeated until there are no crack locations within the spatial neighborhood of the candidate crack points. All candidate crack points constitute the marked locations.

[0067] It should be explained that the preset scale radius refers to the maximum recognition distance extending outward from the current crack location. When the spatial distance between two crack locations is less than or equal to the scale radius, it indicates that there is connectivity. The specific value of the scale radius is set by professionals.

[0068] Extract the point cloud coordinates on both sides of the marked location through domain search;

[0069] The distance between each pair of adjacent points is calculated using the point cloud coordinates on both sides of the marked location. The calculation formula is as follows: , in, , and Let be the point cloud coordinates on one side of the crack. and The coordinates of the point cloud on the other side of the crack. The distance between a pair of adjacent points;

[0070] The maximum distance between adjacent points is used as the crack width at the marked location;

[0071] Filter the point cloud coordinates by traversing the marked locations. Find the point cloud coordinates with the largest absolute value of the axis coordinates, and calculate the coordinates of all point cloud coordinates at unmarked locations by traversing the point cloud coordinates at unmarked locations. Axis mean, the coordinates of the point cloud at the marked location. The point cloud coordinates with the largest absolute value of the axis coordinates Axis coordinate values ​​and coordinates of all point cloud points at unmarked locations The absolute value of the difference between the axis mean values ​​is taken as the concrete spalling thickness at the marked location;

[0072] Only retain the point cloud coordinates of the marked locations. shaft and Axis coordinates and projected onto On a plane, the bounding box is obtained using the convex hull algorithm. The smallest convex hull polygon containing all points on a plane;

[0073] The concrete spalling area is calculated using the vertex coordinates of the minimum convex hull polygon. The formula is as follows: ,in, and The first convex hull polygon The coordinates of each vertex and the coordinates of its adjacent vertices. Let be the number of vertices of the convex hull polygon. The area of ​​concrete spalling at the marked location;

[0074] The point cloud coordinates of various points on the surface of the bending member. The absolute values ​​of the maximum and minimum values ​​of the axis coordinates are added together to obtain the thickness of the member subjected to bending.

[0075] The area of ​​the member subjected to bending is calculated using the convex hull algorithm described above.

[0076] The section loss coefficient is calculated by combining the concrete spalling thickness and area at the marked locations with the thickness and area of ​​the heavily flexural member. The formula is as follows: ,in, and The thickness and area of ​​concrete spalling at the marked locations. and The thickness and area of ​​the bending member are considered. This is the cross-sectional loss coefficient;

[0077] It should be explained that the preset radius is used to fix the area of ​​the point cloud position, which is convenient for determining whether the point is the target point. It is set by professionals. The domain search refers to data querying in a specific domain or range to extract the point cloud coordinates on both sides of the crack. The preset crack feature threshold is an important parameter used to determine whether the target point is the marked position. It is set by professionals. The convex hull algorithm is used to find the convex hull of a set of two-dimensional points and calculate the concrete spalling area and the area of ​​the deeply bent member.

[0078] In step S2, the bearing capacity of the compression bar at the marked location is calculated by combining the crack width at the marked location with the section loss coefficient. The calculation formula is as follows: ,in, The width of the crack at the marked location. This is the cross-sectional loss coefficient. The bearing width of the compression bar at the marked location;

[0079] The load-bearing width of the pressure bar at the marked location is compared with the preset load-bearing width threshold for determination:

[0080] If the load-bearing width of the compression bar at the marked position is greater than the preset load-bearing width threshold, then the marked position is determined to meet the load-bearing width requirement.

[0081] If the load-bearing width of the compression bar at the marked position is less than or equal to the preset load-bearing width threshold, then the marked position is determined to not meet the load-bearing width requirement.

[0082] Record the marked position that meets the load-bearing width requirement as the target position;

[0083] The distance to each target location is calculated using the following formula: ,in, and For the first Point cloud coordinates of each target location. and For the first Point cloud coordinates of each target location. The distance between the two target locations;

[0084] The crack density index is calculated based on the distance to each target location. The calculation formula is as follows: ,in, The distance between the two target locations. For the area of ​​the bending member, The crack density index;

[0085] The crack density index is compared with a preset crack density index threshold for determination.

[0086] If the crack density index is greater than or equal to the preset crack density index threshold, a path migration signal is generated.

[0087] If the crack density index is less than the preset crack density index threshold, no path migration signal will be generated.

[0088] It should be explained that the preset strut bearing width threshold is a key parameter used to determine the maximum width that the strut can bear under specific conditions, and it is set by professionals; the preset crack density index threshold is a standard value used to assess the crack density of an object, and it is set by professionals.

[0089] In step S3, the strain data at the target location typically refers to the strain measured around the crack or at the location of the crack itself. The strain data reflects the deformation of the material or structure under stress, including the peak strain at the target location and the strain amplitude at the target location.

[0090] The preset acquisition period is used to record the center wavelength of the fiber optic grating reflection at each acquisition moment using a fiber optic grating sensor.

[0091] Within the acquisition period, the difference between the center wavelength acquired at each acquisition moment and the center wavelength at the first acquisition moment is taken as the change in the center wavelength at the corresponding acquisition moment.

[0092] The strain value at the target location is calculated based on the change in the center wavelength. The calculation formula is as follows: ,in, It is the change in the center wavelength of the fiber optic grating reflection. It is the original center wavelength of the grating reflection. It is the refractive index of the fiber grating. It is the strain value at the target location;

[0093] The strain values ​​at different acquisition times at the target location are compared to obtain the maximum strain value at the acquisition time at the target location, which is taken as the strain peak value at the target location.

[0094] Divide the difference between the maximum and minimum strain values ​​at the target location by 2 to obtain the strain amplitude at the target location;

[0095] The force transmission path characteristics are calculated by combining the peak strain and strain amplitude at the target location. The calculation formula is as follows: ,in, The peak strain at the target location. The maximum value of the strain peak at all target locations. The strain amplitude at the target location. and To preset the weighting coefficients, Characteristics of the force transmission path;

[0096] It should be noted that the preset weighting coefficients are used to adjust the influence of the peak strain and strain amplitude at the target location on the force transmission path characteristics, and should be set by professionals.

[0097] The larger the strain amplitude and peak strain at the target location, the greater the force transmission fluctuation at the target location, the more uneven the force transmission, and the greater the force transmission path characteristics.

[0098] The smaller the strain amplitude and peak strain at the target location, the smaller the force transmission fluctuation at the target location, the smoother the force transmission, and the smaller the force transmission path characteristics.

[0099] Vibration signals at the target location are collected by vibration sensors and converted into electrical signals. The electrical signals are recorded by a vibration analyzer and converted into vibration accelerations by analog-to-digital conversion.

[0100] It needs to be explained that the preset acquisition period refers to the time interval set in advance during the data acquisition process, used to determine the frequency of data collection; a fiber optic grating sensor is a sensor based on the principle of grating reflection in optical fiber, used to record the center wavelength of the reflected fiber optic grating; a vibration sensor is a device for monitoring the vibration of an object, used to collect vibration signals at the target location and convert them into electrical signals; a vibration analyzer is a device specifically used to measure, analyze, and diagnose the vibration state of an object, used to record electrical signals and obtain vibration acceleration; analog-to-digital conversion is the process of converting analog signals into digital signals, used to convert electrical signals into vibration acceleration.

[0101] In step S4, through The normalization method processes the vibration acceleration and force transmission path characteristics at each target location to obtain normalized values ​​for the vibration acceleration and force transmission path characteristics of each target. The normalized values ​​are: ,in, and These represent the force transmission path characteristics and vibration acceleration at the target location, respectively. and These represent the force transmission path characteristics and the maximum and minimum values ​​of vibration acceleration for each target. and These represent the force transmission path characteristics and the normalized values ​​of vibration acceleration at each target location;

[0102] The path reconstruction index is calculated by combining the force transmission path characteristics at each target location with the normalized value of vibration acceleration. The path reconstruction index is: ,in, The number of target locations, For the first The normalized value of vibration acceleration at each target location For the first The normalized value of the force transmission path characteristics at each target location. For path reconstruction index;

[0103] The larger the force transmission path characteristics and the normalized value of vibration acceleration at the target location, the greater the dynamic change of force at the target location, the more significant the force transmission at the target location, and the larger the path reconstruction index.

[0104] The smaller the force transmission path characteristics and the normalized value of vibration acceleration at the target location, the smaller the dynamic change of the force at the target location, the smaller the change of the force transmission path, and the smaller the path reconstruction index.

[0105] It should be noted that, It indicates the intensity of the change in vibration acceleration. When the vibration acceleration increases, it indicates that the dynamic force at that location has changed significantly, and the impact on the force transmission path of the structure will also increase. This indicates the intensity of change in the force transmission path characteristics. If the force transmission path characteristics at a certain target location change significantly, it means that the force transmission method or path has changed significantly, implying that there is a problem with the structure or materials in that area. This reflects the interaction between vibration acceleration and force transmission path characteristics. If both vibration acceleration and force transmission path characteristics change significantly at the same time, it means that the change in the force transmission path is more complex or drastic.

[0106] The path reconstruction index is compared with a preset path reconstruction index threshold to determine whether the force transmission path has changed.

[0107] If the path reconstruction index is greater than or equal to the preset path reconstruction index threshold, the force transmission path will change.

[0108] If the path reconstruction index is less than the preset path reconstruction index threshold, the force transmission path remains unchanged.

[0109] It needs to be explained that, Normalization is a common numerical normalization technique used to normalize the vibration acceleration and force transmission path characteristics at each target location. The preset path reconstruction index threshold is an important parameter for determining whether the force transmission path has changed. It is set by professionals and will not be elaborated here.

[0110] Changes in the force transmission path reflect the evolution trend of the internal force mode of a bending member structure and are an important indicator of the structure's health status. By integrating vibration acceleration and force transmission path characteristics to construct a path reconstruction index, and judging whether the path has changed based on the path reconstruction index, we can achieve early identification of potential structural instability or local failure risks, and provide a scientific basis for structural safety assessment, operation and maintenance strategy formulation and fault prevention.

[0111] Finally, it should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0112] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0113] In this document, the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that terms such as “comprising / including” or “having” specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0114] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0115] The above description of the disclosed embodiments will enable those skilled in the art to make or use various modifications to these embodiments. It will be readily apparent to those skilled in the art that the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A multi-field joint detection method for force transmission path changes in deeply bent members, characterized in that: Includes the following steps: Step S1: Identify and mark the crack locations of the heavily bent members using a laser scanner, collect the crack width, concrete spalling thickness, and spalling area at the marked locations, and calculate the section loss coefficient using the concrete spalling thickness and spalling area. In step S1, the bending member is scanned by a laser scanner, and the timestamps of laser emission and reception are recorded; The distance from the laser scanner to the surface of the deeply bent component is calculated based on the timestamps of laser emission and reception. The point cloud coordinates of each point on the surface of the deeply bent member are obtained by calculating the distance from the laser scanner to the surface of the deeply bent member. The point cloud coordinates of each point on the surface of the bending member are taken as the target points in sequence, and a spatial neighborhood is constructed with the target points as the center and according to the preset radius. The average Z-axis height of all point cloud coordinates in the spatial neighborhood is calculated. The difference between the Z-axis height value of the target point and the average Z-axis height value of all point cloud coordinate points in the spatial domain is used as the crack feature value; In step S1, the crack feature value is compared with a preset crack feature threshold to determine the crack location: If the crack feature value is less than 0 and the absolute value of the crack feature value is greater than the crack feature value threshold, then the target point is determined to be the crack location. Conversely, if the target point is not located at the crack, then it is determined that the target point is not the location of the crack. Crack locations are determined by filtering candidate crack points through spatial domain analysis, and all the selected candidate crack points are used to form marked locations. The distance between each pair of adjacent points is calculated using the point cloud coordinates on both sides of the marked location, and the maximum distance between adjacent points is taken as the crack width at the marked location. Step S2: Calculate the load-bearing width of the compression member at the marked location by combining the crack width at the marked location with the section loss coefficient. Filter the target locations based on the load-bearing width of the compression member, detect the distance between each target location, analyze the crack density index of the bending member, and determine whether a path migration signal is generated. In step S2, only the point cloud coordinates of the marked locations are retained. shaft and Axis coordinates and projected onto On a plane; The convex hull algorithm is used to obtain the bounding wall. The smallest convex hull polygon containing all points on a plane; The concrete spalling area at the marked location is calculated using the vertex coordinates of the minimum convex hull polygon. According to the marked position The maximum absolute value of the axis and the coordinates of all point cloud points at unmarked locations The absolute value of the difference between the axis mean values ​​is taken as the concrete spalling thickness at the marked location; The cross-sectional loss coefficient is calculated by combining the concrete spalling thickness and concrete spalling area at the marked locations; Step S3: After generating the path migration signal, strain data at each target location is collected based on the fiber optic grating sensor. The force transmission path characteristics at the target location are analyzed based on the strain data, and the vibration acceleration at each target location is detected. Step S4: After processing the vibration acceleration and force transmission path characteristics of each target, evaluate the path reconstruction index of the bending member, and determine whether the force transmission path has changed based on the path reconstruction index.

2. The multi-field joint detection method for force transmission path changes in deeply bent members according to claim 1, characterized in that: In step S2, the bearing capacity of the compression bar at the marked location is calculated by combining the crack width at the marked location with the section loss coefficient; If the load-bearing width of the compression bar at the marked position is greater than the preset load-bearing width threshold, then the marked position is determined to meet the load-bearing width requirement. Conversely, if the marking position does not meet the load-bearing width requirements, it is determined that the marking position does not meet the requirements. Record the marked position that meets the load-bearing width requirement as the target position; The distance between each target location is calculated based on the point cloud coordinates of the target location, and the crack density index is calculated based on the distance between each target location. If the crack density index is greater than or equal to the preset crack density index threshold, a path migration signal is generated. Conversely, no path migration signal is generated.

3. The multi-field joint detection method for force transmission path changes in deeply bent members according to claim 1, characterized in that: In step S3, the strain data at the target location includes the peak strain at the target location and the strain amplitude at the target location; The center wavelength reflected by the fiber optic grating is recorded by a fiber optic grating sensor at a preset acquisition period. Within the acquisition period, the difference between the center wavelength acquired at each acquisition moment and the center wavelength at the first acquisition moment is taken as the change in the center wavelength at the corresponding acquisition moment. Calculate the strain value at the target location based on the change in the center wavelength; The difference between the maximum and minimum strain values ​​at the target location is divided by 2 to obtain the strain amplitude at the target location.

4. The multi-field joint detection method for force transmission path changes in deeply bent members according to claim 3, characterized in that: In step S3, the force transmission path characteristics are obtained by weighted calculation of the peak strain value and the strain amplitude at the target location. Vibration signals at the target location are collected by vibration sensors and converted into electrical signals. The electrical signals are then recorded by a vibration analyzer and converted into vibration acceleration at the target location.

5. A multi-field joint detection method for force transmission path changes in deeply bent members according to claim 4, characterized in that: In step S4, the path reconstruction index is calculated after normalizing the vibration acceleration and force transmission path characteristics at each target location.

6. A multi-field joint detection method for force transmission path changes in deeply bent members according to claim 5, characterized in that: In step S4, if the path reconstruction index is greater than or equal to the preset path reconstruction index threshold, the force transmission path changes. If the path reconstruction index is less than the preset path reconstruction index threshold, the force transmission path remains unchanged.

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