A building structure mechanics detection method and system

Abstract

The application provides a building structure mechanics detection method and system, marks the concrete structure of the fabricated building as a plurality of detection units, extracts the drift characteristics of the reflected echo propagation in the concrete medium from the time domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and then maps the drift characteristics to the grouting saturation of the concrete structure in the fabricated building; based on the grouting saturation, a multi-stage cyclic load is applied at the connection node of the fabricated building, and the displacement information at the connection node under the multi-stage cyclic load is read, and then the inflection point of the hysteresis curve of the load at the connection node of the fabricated building is extracted from the displacement information; according to the inflection point of the hysteresis curve of the load and the grouting saturation, the mechanical stability of the connection node component of the fabricated building is fused and evaluated, and the stability grade of the structure mechanics of the fabricated building is obtained. Based on the above scheme, multi-dimensional fusion evaluation of the mechanical stability of the fabricated building can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acoustic wave monitoring, and more particularly to a building structure mechanics detection method and system. BACKGROUND

[0002] In prefabricated buildings, structural mechanics research focuses on the fine analysis of joint connection performance. Through acoustic emission monitoring, digital image correlation technology and other means, real-time perception of the mechanical behavior of prefabricated components is achieved. Intelligent construction technology promotes the deep integration of structural mechanics, BIM and the Internet of Things. Based on finite element simulation and machine learning algorithms, a digital twin model of the structure's health state is established.

[0003] Traditional prefabricated building detection methods have significant evaluation one-sidedness problems. Cyclic loading tests can only obtain macroscopic deformation data and cannot detect internal material defects (e.g., insufficient grouting), and usually only apply a load of up to 80% of the design load, resulting in about 23% of the dangerous nodes being misjudged as safe. Visual inspection is completely limited to surface defect observation. Both methods analyze material performance and structural response separately, which cannot capture the stress redistribution effect caused by grouting defects and lack time-domain monitoring of the damage accumulation process, making it difficult to meet the needs of modern prefabricated building life cycle fine management. Therefore, how to realize multi-dimensional fusion evaluation of mechanical stability in prefabricated buildings has become a difficult problem in the industry. SUMMARY

[0004] The present application provides a building structure mechanics detection method and system, which can realize multi-dimensional fusion evaluation of mechanical stability in prefabricated buildings.

[0005] In a first aspect, the present application provides a building structure mechanics detection method, wherein acoustic wave sensors are pre-installed on the surface of the connecting node components of the prefabricated building, and a transient shock wave is excited on the building surface. The shock wave propagates in the concrete medium of the prefabricated building and is reflected into the acoustic wave sensor. The method comprises:

[0006] Collecting the time-domain waveform of the reflected echo in the acoustic wave sensor;

[0007] Marking the concrete structure of the prefabricated building as a plurality of detection units, and then extracting the drift feature of the reflected echo propagating in the concrete medium from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and mapping the drift feature to the grouting saturation of the concrete structure in the prefabricated building according to the mapping relationship between the wave speed of the reflected echo and the grouting state;

[0008] applying a multi-stage cyclic load of non-destructive testing at the fabricated building connection node based on the grouting saturation, reading displacement information at the connection node under the multi-stage cyclic load, and then extracting a hysteresis curve inflection point of the load at the fabricated building connection node from the displacement information;

[0009] fusing the hysteresis curve inflection point of the load and the grouting saturation to evaluate the mechanical stability of the fabricated building connection node component, and obtaining a stability level of the mechanical stability of the fabricated building structure.

[0010] In some embodiments, marking the concrete structure of the fabricated building as a plurality of detection units specifically includes:

[0011] obtaining a topological relationship of an array of acoustic wave sensors in the fabricated building;

[0012] marking the concrete structure of the fabricated building as a plurality of detection units based on the topological relationship.

[0013] In some embodiments, extracting a drift feature of the reflected echo propagating in the concrete medium from the time-domain waveform through a time delay characteristic of the stress wave propagation path in each detection unit specifically includes:

[0014] obtaining a first wave time point of each detection unit from the time-domain waveform, and then determining a stress wave propagation time delay between adjacent detection units;

[0015] determining the drift feature of the reflected echo propagating in the concrete medium through all stress wave propagation time delays.

[0016] In some embodiments, mapping the drift feature to a grouting saturation of the concrete structure in the fabricated building according to a mapping relationship between the wave speed of the reflected echo and the grouting state specifically includes:

[0017] preparing concrete test pieces of different grouting saturations, then measuring the wave speed of the reflected echo in different concrete test pieces, and establishing a mapping relationship between the wave speed of the reflected echo and the grouting state;

[0018] calculating a propagation speed of the reflected echo in each detection unit of the concrete medium through the drift feature;

[0019] determining the grouting saturation of the concrete structure in the fabricated building according to the grouting state of each propagation speed in the mapping relationship.

[0020] In some embodiments, applying a multi-stage cyclic load of non-destructive testing at the fabricated building connection node based on the grouting saturation specifically includes:

[0021] grading the design load of the fabricated building through the grouting saturation to obtain a multi-stage test load of the loading device;

[0022] The multi-stage cyclic load for non-destructive testing is applied to the fabricated building connection joint using various test loads, and a displacement meter is arranged at the fabricated building connection joint to record the stable displacement under each stage of cyclic load.

[0023] In some embodiments, extracting the inflection point of the load hysteresis curve at the fabricated building connection joint from the displacement information specifically includes:

[0024] Generating a load-displacement curve through each stable displacement in the displacement information;

[0025] Identifying the sudden increase point in the load-displacement curve as the inflection point of the load hysteresis curve at the fabricated building connection joint.

[0026] In some embodiments, the mechanical stability of the fabricated building connection joint component is fused and evaluated according to the inflection point of the load hysteresis curve and the grouting saturation, to obtain the stability level of the mechanical stability of the fabricated building structure specifically includes:

[0027] Fusing the inflection point of the load hysteresis curve and the grouting saturation to obtain the mechanical stability index of the fabricated building connection joint component;

[0028] Dividing the stability level of the mechanical stability of the fabricated building structure through the mechanical stability index.

[0029] In a second aspect, the present application provides a building structure mechanical detection system, wherein a sound wave sensor is pre-installed on the surface of the fabricated building connection joint component, and a transient shock wave is excited on the building surface, the shock wave propagates in the concrete medium of the fabricated building and is reflected into the sound wave sensor, and the system includes:

[0030] The acquisition module is configured to acquire the time-domain waveform of the reflected echo in the sound wave sensor;

[0031] The processing module is configured to mark the concrete structure of the fabricated building as a plurality of detection units, and then extract the drift feature of the reflected echo propagating in the concrete medium from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and map the drift feature to the grouting saturation of the concrete structure in the fabricated building according to the mapping relationship between the wave speed of the reflected echo and the grouting state;

[0032] The processing module is further configured to apply a multi-stage cyclic load for non-destructive testing at the fabricated building connection joint based on the grouting saturation, and read the displacement information at the connection joint under the multi-stage cyclic load, and then extract the inflection point of the load hysteresis curve at the fabricated building connection joint from the displacement information;

[0033] The execution module is configured to perform fusion evaluation on the mechanical stability of the connecting joint component of the fabricated building according to the inflection point of the hysteresis curve of the load and the grouting saturation, and obtain the stability grade of the mechanical stability of the fabricated building structure.

[0034] In a third aspect, the present application provides a computer device, which comprises a memory and a processor, the memory is configured to store a computer program, and the processor is configured to call and run the computer program from the memory, so that the computer device executes the building structure mechanical detection method described above.

[0035] In a fourth aspect, the present application provides a computer readable storage medium, which stores instructions or codes, when the instructions or codes are run on a computer, the computer executes the building structure mechanical detection method described above.

[0036] The technical scheme provided by the embodiments of the present application has the following beneficial effects:

[0037] In the building structure mechanical detection method and system provided by the present application, the time-domain waveform of the reflected echo in the acoustic wave sensor is collected; the concrete structure of the fabricated building is marked as a plurality of detection units, and then the drift feature of the reflected echo propagating in the concrete medium is extracted from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and the drift feature is mapped to the grouting saturation of the concrete structure in the fabricated building according to the mapping relationship between the wave velocity of the reflected echo and the grouting state; the multi-stage cyclic load of nondestructive testing is applied at the connecting joint of the fabricated building based on the grouting saturation, and the displacement information at the connecting joint under the multi-stage cyclic load is read, and then the inflection point of the hysteresis curve of the load at the connecting joint of the fabricated building is extracted from the displacement information; the mechanical stability of the connecting joint component of the fabricated building is evaluated according to the inflection point of the hysteresis curve of the load and the grouting saturation, and the stability grade of the mechanical stability of the fabricated building structure is obtained.

[0038] Therefore, in the present application, the mechanical stability of the fabricated building connection joint component is fused and evaluated according to the inflection point of the load hysteresis curve and the grouting saturation, and the stability grade of the mechanical stability of the fabricated building structure is obtained; wherein, determining the grouting saturation provides key data support for multi-dimensional evaluation of the mechanical stability of the fabricated building, based on the wave speed-saturation mapping relationship calibrated in the laboratory, the system can convert the stress wave drift characteristics measured on site into accurate grouting saturation values, not only overcoming the error limit of ± 30% of the artificial knocking method, but also identifying the key quality threshold below 80%, and the grouting saturation as a material performance indicator provides a scientific basis for subsequent load classification of cyclic loading tests, when insufficient grouting of a node is detected (for example: grouting saturation < 80%), the system will automatically reduce the maximum test load and increase the loading number, which not only ensures the safety of detection, but also more finely captures the influence of material defects on structural performance; then, determining the inflection point of the hysteresis curve provides a key criterion for the structural response dimension of the mechanical stability evaluation of the fabricated building joint, the inflection point of the hysteresis curve extracted by the numerical differential algorithm not only contains the absolute bearing capacity index of the critical load, but also quantifies the ductility performance of the joint through the stiffness ratio before and after the inflection point, which can predict the joint yield trend far below the failure load (such as 60% P design), and distinguish between brittle failure caused by grouting defects and plastic failure caused by improper construction, thereby improving the forward-looking and reliability of stability evaluation; in summary, based on the above scheme, multi-dimensional fusion evaluation of the mechanical stability of the fabricated building can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0040] Figure 1 is an exemplary flowchart of a building structure mechanical detection method according to some embodiments of the present application;

[0041] Figure 2 is a workflow diagram of the impact echo method according to some embodiments of the present application;

[0042] Figure 3 is a flowchart of determining the time delay distribution entropy according to some embodiments of the present application;

[0043] Figure 4 is a structural diagram of a building structure mechanical detection system according to some embodiments of the present application;

[0044] Figure 5 FIG. 1 is a structural schematic diagram of a computer device for implementing a building structure mechanics detection method according to some embodiments of the present application. DETAILED DESCRIPTION

[0045] In order to better understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with the drawings of the specification and specific embodiments.

[0046] Reference Figure 1 The figure is an exemplary flowchart of a building structure mechanics detection method according to some embodiments of the present application, wherein a sound wave sensor is pre-installed on the surface of a fabricated building connecting node component, and a transient impact wave is excited on the building surface, the impact wave propagates in the concrete medium of the fabricated building and is reflected into the sound wave sensor, the building structure mechanics detection method mainly includes the following steps:

[0047] In step 101, the time domain waveform of the reflected echo in the sound wave sensor is collected.

[0048] It should be noted that in the present application, the time domain waveform represents the propagation process of the impact wave in the concrete medium; the sound wave sensor is a magnetic attraction type sound wave sensor; in the specific implementation, in the detection of the fabricated building connecting node component, first, a flat area is selected on the node surface (avoiding the steel bar dense area and the grouting hole), a magnetic attraction type sound wave sensor (frequency range 20 kHz-100 kHz) is arranged, and the sensor is ensured to be in close contact with the concrete surface through coupling agent; then, a standard impact hammer (hammer head material is nylon or steel, weight 500 g-1 kg) is used to vertically knock the node surface (knocking point is 10-20 cm away from the sensor), the knocking force is controlled (peak force is about 100 N, which can be calibrated through a force sensor) to excite a transient impact wave; the impact wave propagates in the concrete medium and is reflected, and the reflected echo signal is received by the sound wave sensor, the time domain waveform (time length 10-20 ms) is recorded by a multi-channel data acquisition instrument (such as a NI PXI system, sampling frequency ≥200 kHz), and synchronous triggering collection is performed to ensure time zero alignment; finally, the collected time domain waveform is preprocessed (such as band-pass filtering 10 kHz-80 kHz, wavelet denoising db4 base), the first wave arrival time (TOF) and amplitude characteristics are extracted, and a high-quality data basis is provided for subsequent analysis, which combines the impact echo method and the sound wave sensing technology in the existing non-destructive detection technology, and ensures data reliability and repeatability through standardized operation.

[0049] In some embodiments, reference Figure 2The figure is a workflow diagram of the impact echo method according to some embodiments of the present application. First, a transient impact is applied to the surface of the structure by an impact sensor (such as a force hammer), and a displacement sensor is triggered synchronously to record the time-domain waveform. Then, the original waveform signal is transmitted to the analysis system by the data acquisition system, and the frequency spectrum is obtained by fast Fourier transform (FFT) processing, realizing the signal feature analysis from the time domain (displacement-time relationship) to the frequency domain (amplitude-frequency relationship). The system can accurately extract the stress wave propagation characteristics (such as the first wave arrival time and the main frequency shift) through waveform morphology analysis and frequency spectrum peak identification, and provide quantitative basis for internal defect detection of the structure.

[0050] In step 102, the concrete structure of the fabricated building is marked as a plurality of detection units, and then the drift characteristics of the reflected echo propagating in the concrete medium are extracted from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and the drift characteristics are mapped to the grouting saturation of the concrete structure in the fabricated building according to the mapping relationship between the wave velocity of the reflected echo and the grouting state.

[0051] In some embodiments, marking the concrete structure of the fabricated building as a plurality of detection units can be achieved by the following steps:

[0052] Obtain the topological relationship of the acoustic sensor array in the fabricated building;

[0053] Mark the concrete structure of the fabricated building as a plurality of detection units based on the topological relationship.

[0054] It should be noted that in the present application, the detection unit; when implemented, first, the topological relationship of the acoustic sensor array in the fabricated building can be obtained by the following method, that is: in the detection of the fabricated building, the topological relationship network of the sensor array is established by the pre-arranged acoustic sensor coordinates of the three-dimensional laser scanning (with a GPS positioning accuracy of ±1mm); then, the concrete structure of the fabricated building can be marked as a plurality of detection units based on the topological relationship, that is: the concrete structure is divided into continuous detection units (unit size 20cm×20cm) by using the triangulation algorithm (for example: Delaunay algorithm), each detection unit is composed of 3-4 adjacent sensors to form a detection sub-region, and the corresponding relationship between the unit number and the sensor group is established by topological mapping, the detection unit is virtually marked by using the finite element mesh generation technology (for example: ANSYS Meshing), to ensure that the unit boundary is aligned with the structure characteristics, and the material attribute parameters (such as elastic modulus and density) of each detection unit are recorded, so as to obtain a plurality of detection units.

[0055] It should be noted that the above implementation fuses modern surveying and mapping technology, computational geometry method and engineering simulation means, which not only guarantees the accuracy of the detection unit division, but also has engineering practicability; the detection unit refers to an independent space unit for stress wave propagation characteristic analysis; the topological relationship is a mathematical model for describing the spatial connection relationship between sensors in the acoustic sensor array.

[0056] In some embodiments, the step of extracting the drift feature of the reflected echo propagating in the concrete medium from the time-domain waveform by the time delay characteristic of the stress wave propagation path in each detection unit can be implemented as follows:

[0057] Obtaining the first wave time point of each detection unit from the time-domain waveform, and then determining the stress wave propagation time delay between adjacent detection units;

[0058] Determining the drift feature of the reflected echo propagating in the concrete medium by all stress wave propagation time delays.

[0059] It should be noted that in this application, the drift feature refers to the variation of the waveform characteristic parameter caused by the material inhomogeneity (such as grouting defects, cracks, etc.) during the propagation of the stress wave in the concrete medium; the stress wave propagation time delay represents the time difference of the stress wave propagation between adjacent detection units.

[0060] In specific implementation, firstly, the step of obtaining the first wave time point of each detection unit from the time-domain waveform, and then determining the stress wave propagation time delay between adjacent detection units can be implemented as follows: pre-processing the time-domain waveform corresponding to each detection unit, performing noise reduction processing by wavelet transform (for example: db4 wavelet basis), and accurately identifying the first wave arrival time point by adaptive threshold method (set to 3 times the standard deviation of background noise), so as to take the time difference between the first wave arrival time points in adjacent detection units as the stress wave propagation time delay, and thus obtain the stress wave propagation time delay between adjacent detection units; then, the step of determining the drift feature of the reflected echo propagating in the concrete medium by all stress wave propagation time delays can be implemented as follows: for each group of adjacent detection units, measuring the distance between adjacent detection units, taking the ratio of the distance to the stress wave propagation time delay of adjacent detection units as the propagation speed of stress wave between adjacent detection units, and thus taking the difference between the propagation speed and the standard propagation speed of stress wave in the concrete medium as the speed drift value of the reflected echo propagating between adjacent detection units, and then obtaining the speed drift value of the reflected echo propagating between each group of adjacent detection units, and thus taking the set of all speed drift values as the drift feature of the reflected echo propagating in the concrete medium.

[0061] In some embodiments, the step of mapping the drift feature to the grouting saturation of the concrete structure in the fabricated building according to the mapping relationship between the wave speed of the reflected echo and the grouting state can be implemented as follows:

[0062] Preform different grouting saturation of concrete test piece, and then measure the wave speed of the reflected echo in different concrete test pieces, and establish a mapping relationship between the wave speed of the reflected echo and the grouting state;

[0063] Calculate the propagation speed of the reflected echo of the reflected echo in each detection unit of the concrete medium through the drift feature;

[0064] According to the grouting state of each propagation speed in the mapping relationship, the grouting saturation of the concrete structure in the fabricated building is determined.

[0065] It should be noted that in the present application, the grouting saturation represents a quantitative index of the filling and compactness of the grouting material in the fabricated building joint; the propagation speed represents the travel rate of the stress wave in the concrete medium; and the mapping relationship represents a model of the corresponding relationship between the wave speed and the saturation.

[0066] In a specific implementation, first, concrete specimens with different grouting saturations are prepared, then the wave velocities of the reflected echoes in different concrete specimens are measured, and a mapping relationship between the wave velocities of the reflected echoes and the grouting state is established. The mapping relationship can be established in the following manner: in the laboratory calibration stage, a group of grouting saturation gradient samples (30%, 50%, 70%, 90%, and 100%) are prepared, and the samples are cured for 28 days under standard curing conditions (temperature 20±2℃, relative humidity ≥95%). The longitudinal wave velocity of each sample is measured by the ultrasonic pulse velocity method (UPV) (transmission frequency 54 kHz, sampling interval 0.1 microseconds), and the average value of 5 measurements in different directions is obtained. A wave velocity-saturation database is established, and a quantitative relationship model between the wave velocity and the saturation is obtained by fitting the wave velocity and the saturation in the wave velocity-saturation database by the least squares method (v=a*S+b, where v is the wave velocity, S is the saturation, and a and b are material constants). The determination coefficient in the least squares fitting is greater than or equal to 0.95, so that the quantitative relationship model can be used as the mapping relationship between the wave velocity and the grouting state (saturation in this application) in actual detection. In actual detection, the time-domain waveform data collected on site is used to calculate the first wave arrival time difference of each detection unit by the cross-correlation algorithm, and the actual wave velocity is obtained by combining the unit spacing (actual wave velocity=unit spacing / first wave arrival time difference). Then, the actual wave velocity is substituted into the calibration model to obtain the saturation (saturation=(actual wave velocity-b) / a), and the saturation distribution cloud map of the node region is generated by spatial interpolation. Then, the propagation velocity of the reflected echo in each detection unit of the concrete medium can be calculated in the following manner: for each detection unit, all the propagation velocities between the detection unit and the adjacent detection units are obtained from the drift feature, and the average value of all the propagation velocities is used as the propagation velocity of the reflected echo in the detection unit of the concrete medium. In this way, the propagation velocity of the reflected echo in each detection unit of the concrete medium can be obtained. Finally, the grouting saturation of the concrete structure in the fabricated building can be determined in the following manner: for each detection unit, the saturation in the grouting state corresponding to the propagation velocity of the detection unit in the mapping relationship is used as the grouting saturation value of the detection unit. In this way, the grouting saturation values of all the detection units can be obtained, and the average value of all the grouting saturation values is used as the grouting saturation of the concrete structure in the fabricated building.

[0067] In step 103, a multi-stage cyclic load is applied to the fabricated building connection node based on the grouting saturation, and the displacement information of the connection node under the multi-stage cyclic load is read, and then the hysteresis curve inflection point of the load at the fabricated building connection node is extracted from the displacement information.

[0068] In some embodiments, the following steps can be taken to apply the multi-stage cyclic load of non-destructive testing at the fabricated building connection joint based on the grouting saturation degree:

[0069] The design load of the fabricated building is graded by the grouting saturation degree to obtain the multi-stage test load of the loading device;

[0070] The multi-stage cyclic load of non-destructive testing is applied at the fabricated building connection joint using each test load, and the stable displacement under each stage of cyclic load is recorded by arranging displacement meters at the fabricated building connection joint.

[0071] In specific implementation, first, the design load of the fabricated building is graded by the grouting saturation degree to obtain the multi-stage test load of the loading device, which can be implemented in the following manner: when the grouting saturation degree is ≥ 90%, the standard grading (0.2P_d, 0.4P_d, 0.6P_d, 0.8P_d, 1.0P_d, a total of 5 stages) is used, when 80% ≤ grouting saturation degree < 90%, the transition stage is increased to 7 stages (each stage increases by 0.15P_d), and when the grouting saturation degree is < 80%, the grading is increased (0.1P_d per stage, a total of 10 stages) and the maximum load limit is set to 0.7P_d, wherein P_d refers to the design load unit of the cyclic load test; then, the multi-stage cyclic load of non-destructive testing is applied at the fabricated building connection joint using each test load, and the stable displacement under each stage of cyclic load is recorded by arranging displacement meters at the fabricated building connection joint, which can be implemented in the following manner: the test uses a servo hydraulic loading system (precision ±1%FS), and the load is applied step by step through force control mode, each stage holds the load for 5 minutes and monitors the displacement change rate, when the displacement change rate is ≤ 0.01mm / min for 3 consecutive minutes, it is determined that the state is stable, 4-8 high-precision LVDT displacement meters (range ±50mm, resolution 0.001mm) are symmetrically arranged at the key parts of the node (e.g. beam end, column foot and joint), and a dynamic data acquisition instrument (sampling frequency 10Hz) is used to record the displacement of the displacement meter under each stage of cyclic load as the stable displacement, i.e. the stable displacement under each stage of cyclic load is obtained.

[0072] It should be noted that, in the implementation phase of the cyclic load test, the grading loading strategy can effectively evaluate the actual bearing capacity of nodes with different grouting quality, avoid structural damage caused by overloading, and provide reliable basis for subsequent stability evaluation; FS refers to the maximum value of the measurement range of the system, which is used to describe the range of the measuring device; the stable displacement is a displacement value reflecting the stable deformation response of the structure under each stage of load; the multi-stage test load is a loading sequence revealing the nonlinear mechanical behavior of the fabricated building structure.

[0073] In some embodiments, reading the displacement information at the connection node under multi-level cyclic loading can be achieved in the following manner: for each level of cyclic loading test, all stable displacement values and corresponding load values in the cyclic loading test are obtained, and the set of all stable displacement values and corresponding load values is taken as the displacement information of the cyclic loading test. In this way, the displacement information of each level of cyclic loading test can be obtained, and the displacement information at the connection node under multi-level cyclic loading can be obtained.

[0074] In some embodiments, extracting the inflection point of the hysteretic curve of the load at the prefabricated building connection node from the displacement information can be achieved in the following steps:

[0075] Generating a load-displacement curve from each stable displacement value in the displacement information;

[0076] Identifying the sudden increase point in the load-displacement curve as the inflection point of the hysteretic curve of the load at the prefabricated building connection node.

[0077] It should be noted that in this application, the inflection point of the hysteretic curve is a critical state point representing the initial bearing capacity of the structure when it transitions from the elastic stage to the plastic deformation stage; the load-displacement curve is a constitutive relationship curve describing the mechanical properties of prefabricated building structures.

[0078] In specific implementation, first, generating a load-displacement curve from each stable displacement value in the displacement information can be achieved in the following manner: initializing a Cartesian coordinate system, with the horizontal coordinate being the stable displacement value and the vertical coordinate being the load value, mapping the stable displacement values and corresponding loads of each level of cyclic loading test to the coordinate system, and then using a cubic spline interpolation method to construct a continuous curve as the load-displacement curve; then, calculating the first derivative (stiffness K = dP / dL) and the second derivative (curvature = d²P / dL²) of the curve by numerical differentiation, where L is the stable displacement value and P is the load value. When a stiffness mutation (more than 3 times the standard deviation of the average value of the previous three levels) occurs and is accompanied by a K value drop of more than 15%, the point is determined to be the inflection point of the hysteretic curve. The inflection point position is marked by a visualization software, and the stiffness ratio = tangent line stiffness before inflection point / secant line stiffness after inflection point is calculated as a quantitative indicator of node plasticity development. In this way, the inflection point of the hysteretic curve of the load at the prefabricated building connection node can be obtained. In other embodiments, to eliminate the influence of measurement noise, the original displacement data can be smoothed by a Savitzky-Golay filter (window width 5 points, 2nd order polynomial) in advance, which is not limited here.

[0079] In step 104, the mechanical stability of the prefabricated building connection component is fused and evaluated according to the inflection point of the hysteretic curve of the load and the grouting saturation, and the stability grade of the prefabricated building structure mechanics is obtained.

[0080] In some embodiments, the mechanical stability of the prefabricated building connection joint component is fused and evaluated according to the inflection point of the hysteresis curve of the load and the grouting saturation, to obtain a stability level of the prefabricated building structure mechanics, and the stability level of the prefabricated building structure mechanics is determined according to the following formula: Figure 3 The figure is a flowchart for determining the delay distribution entropy in some embodiments of the present application. In the present embodiment, the delay distribution entropy can be determined by the following steps:

[0081] In step 1041, the mechanical stability index of the prefabricated building connection joint component is obtained by multi-parameter fusion of the inflection point of the hysteresis curve of the load and the grouting saturation.

[0082] In step 1042, the stability level of the prefabricated building structure mechanics is divided by the mechanical stability index.

[0083] It should be noted that in the present application, the stability level represents the level of the safety state at the prefabricated building connection joint; and the mechanical stability index is an index for quantifying the stability of the mechanical performance of the prefabricated building structure.

[0084] In specific implementation, first, the mechanical stability index of the prefabricated building connection joint component can be obtained by multi-parameter fusion of the inflection point of the hysteresis curve of the load and the grouting saturation in the following manner: the grouting saturation is converted into a relative value in the interval [0, 1], i.e., relative value = grouting saturation / 100%, the inflection point load is converted into a load retention rate, i.e., load retention rate = inflection point load / design load, and the stiffness ratio is directly used as a deterioration index; the weights of the parameters are determined based on the analytic hierarchy process (the weight of the relative value is 0.5, the weight of the load retention rate is 0.3, and the weight of the deterioration index is 0.2), so as to calculate the mechanical stability index of the prefabricated building connection joint component by using a nonlinear fusion function (mechanical stability index = 1-exp[-2.5(relative value^0.5x load retention rate^0.3x(2-deterioration index)^0.2)]); then, the stability level of the prefabricated building structure mechanics can be divided by the mechanical stability index in the following manner: the historical detection data are trained by using the K-means clustering algorithm (default: k = 3) to automatically divide the level threshold; when the mechanical stability index is greater than or equal to 0.82, it is level I (safe); when 0.65 is less than the mechanical stability index and is greater than or equal to 0.82, it is level II (warning); and when the mechanical stability index is less than 0.65, it is level III (dangerous).

[0085] In addition, another aspect of the present application provides a building structure mechanics detection system in some embodiments, which is determined according to the following formula: Figure 4Fig. 1 is a structural schematic diagram of a building structure mechanics detection system according to some embodiments of the present application, wherein a surface of a fabricated building connecting joint component is pre-installed with a sound wave sensor, and a transient shock wave is excited on the building surface, the shock wave propagates in the concrete medium of the fabricated building and is reflected into the sound wave sensor, the building structure mechanics detection system comprises a collection module 201, a processing module 202 and an execution module 203, which are described as follows:

[0086] The collection module 201 is mainly used for collecting the time-domain waveform of the reflected echo in the sound wave sensor in the present application;

[0087] The processing module 202 is used for marking the concrete structure of the fabricated building as a plurality of detection units in the present application, and then extracting the drift feature of the reflected echo propagating in the concrete medium from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and mapping the drift feature to the grouting saturation of the concrete structure in the fabricated building according to the mapping relationship between the wave velocity of the reflected echo and the grouting state;

[0088] It should be noted that the processing module 202 is also used for applying a multi-stage cyclic load for non-destructive testing at the connecting joint of the fabricated building based on the grouting saturation, and reading the displacement information at the connecting joint under the multi-stage cyclic load, and then extracting the hysteresis curve inflection point of the load at the connecting joint of the fabricated building from the displacement information;

[0089] The execution module 203 is mainly used for fused evaluation of the mechanical stability of the connecting joint component of the fabricated building according to the hysteresis curve inflection point of the load and the grouting saturation, to obtain the stability grade of the building structure mechanics.

[0090] The above describes the examples of the building structure mechanics detection method and system provided by the embodiments of the present application in detail. It can be understood that the corresponding device contains the hardware structure and / or software module corresponding to the execution of each function in order to realize the above functions. Those skilled in the art should easily realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the present application can be realized in the form of hardware or a combination of hardware and computer software. Whether a certain function is executed by hardware or computer software driven hardware depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0091] In some embodiments, the present application also provides a computer device, comprising a memory and a processor, the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that the computer device executes the building structure mechanics detection method described above.

[0092] In some embodiments, with reference to Figure 5 The dashed line in the figure indicates that the unit or the module is optional, and the figure is a structural schematic diagram of a computer device for implementing the building structure mechanics detection method according to the embodiments of the present application. The building structure mechanics detection method described in the above embodiments can be implemented by the computer device shown in the figure, which comprises at least one processor 301, a memory 302, and at least one communication unit 305, and the computer device can be a terminal device or a server or a chip. Figure 5

[0093] The processor 301 can be a general-purpose processor or a special-purpose processor. For example, the processor 301 can be a central processing unit (CPU), which can be used to control the computer device, execute the software program, and process the data of the software program. The computer device can also include a communication unit 305 to realize the input (reception) and output (transmission) of signals.

[0094] For example, the computer device can be a chip, and the communication unit 305 can be an input and / or output circuit of the chip, or the communication unit 305 can be a communication interface of the chip, and the chip can be a component of a terminal device or a network device or other devices.

[0095] For another example, the computer device can be a terminal device or a server, and the communication unit 305 can be a transceiver of the terminal device or the server, or the communication unit 305 can be a transceiver circuit of the terminal device or the server.

[0096] The computer device can include one or more memories 302, which have programs 304 stored thereon, and the programs 304 can be run by the processor 301 to generate instructions 303, so that the processor 301 executes the method described in the above method embodiments according to the instructions 303. Optionally, the memory 302 can also store data (such as a target audit model). Optionally, the processor 301 can also read the data stored in the memory 302, and the data can be stored in the same storage address as the program 304, or the data can be stored in a different storage address from the program 304.

[0097] ​The processor 301 and the memory 302 can be separately arranged or integrated together, for example, on a system on chip (SOC) of the terminal device.

[0098] It should be understood that each step of the above method embodiments can be completed by a logic circuit in the form of hardware or instructions in the form of software in the processor 301, and the processor 301 can be a CPU, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, for example, discrete gates or transistor logic devices, or discrete hardware components.

[0099] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage devices, etc.) containing computer-usable program code.

[0100] For example, in some embodiments, the present application also provides a computer-readable storage medium, which stores instructions or codes, when the instructions or codes are run on a computer, cause the computer to perform the above-mentioned building structure mechanics detection method.

[0101] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0102] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method of detecting structural mechanics of a building, wherein, The surface of the prefabricated building connecting node component is provided with a sound wave sensor in advance, and a transient shock wave is excited on the building surface, the shock wave propagates in the concrete medium of the prefabricated building and is reflected into the sound wave sensor, and the method comprises the following steps: Collecting the time-domain waveform of the reflected echo in the sound wave sensor; Marking the concrete structure of the prefabricated building as a plurality of detection units, and then extracting the drift characteristics of the reflected echo propagating in the concrete medium from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and mapping the drift characteristics to the grouting saturation of the concrete structure in the prefabricated building according to the mapping relationship between the wave velocity of the reflected echo and the grouting state; Based on the grouting saturation, a multi-stage cyclic load for non-destructive testing is applied at the connecting node of the prefabricated building, and the displacement information at the connecting node under the multi-stage cyclic load is read, and then the inflection point of the load of the connecting node of the prefabricated building is extracted from the displacement information, wherein the inflection point of the hysteresis curve is a critical state point representing the initial bearing capacity of the structure from the elastic stage to the plastic deformation; According to the inflection point of the load of the hysteresis curve and the grouting saturation, the mechanical stability of the prefabricated building connecting node component is fused and evaluated, and the stability grade of the prefabricated building structure mechanics is obtained, which comprises: Multi-parameter fusion of the inflection point of the load of the hysteresis curve and the grouting saturation is performed to obtain the mechanical stability index of the prefabricated building connecting node component, that is, the grouting saturation is converted into a relative value in the interval [0, 1], that is, the relative value = grouting saturation / 100%, the inflection point load is converted into a load retention rate, that is, the load retention rate = inflection point load / design load, and the stiffness ratio is directly used as a deterioration index, the weights of each parameter are determined based on the analytic hierarchy process, and a nonlinear fusion function is used, that is, the mechanical stability index = 1-exp[-2.5(relative value^0.5×load retention rate^0.3×(2-deterioration index)^0.2)], to calculate the mechanical stability index of the prefabricated building connecting node component; The stability grade of the prefabricated building structure mechanics is divided by the mechanical stability index.

2. The method of claim 1, wherein, Marking the concrete structure of the prefabricated building as a plurality of detection units specifically comprises: Obtaining the topological relationship of the sound wave sensor array in the prefabricated building; Based on the topological relationship, the concrete structure of the prefabricated building is marked as a plurality of detection units.

3. The method of claim 1, wherein, Extracting the drift characteristics of the reflected echo propagating in the concrete medium from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit specifically comprises: Obtaining the first wave time point of each detection unit from the time-domain waveform, and then determining the stress wave propagation time delay between adjacent detection units; The drift characteristics of the reflected echo propagating in the concrete medium are determined through all the stress wave propagation time delays.

4. The method of claim 1, wherein, Mapping the drift characteristics to the grouting saturation of the concrete structure in the prefabricated building according to the mapping relationship between the wave velocity of the reflected echo and the grouting state specifically comprises: Preparing concrete specimens with different grouting saturations, and then measuring the wave velocity of the reflected echo in different concrete specimens, and establishing the mapping relationship between the wave velocity of the reflected echo and the grouting state; Calculate the propagation speed of the reflected echo in each detection unit of the concrete medium through the drift feature of the reflected echo; Determine the grouting saturation of the concrete structure in the prefabricated building according to the grouting state of each propagation speed in the mapping relationship.

5. The method of claim 1, wherein, Based on the grouting saturation, a multi-stage cyclic load for non-destructive testing is applied at the connecting joint of the prefabricated building, which specifically includes: Through the grouting saturation, the design load of the prefabricated building is graded to obtain a multi-stage test load of the loading device; Using each test load, a multi-stage cyclic load for non-destructive testing is applied at the connecting joint of the prefabricated building, and a displacement meter is arranged at the connecting joint of the prefabricated building to record the stable displacement under each stage of cyclic load.

6. The method of claim 1, wherein, From the displacement information, the inflection point of the hysteresis curve of the load at the connecting joint of the prefabricated building is extracted, which specifically includes: Generate a load-displacement curve through each stable displacement in the displacement information; Identify the sudden increase point in the load-displacement curve as the inflection point of the hysteresis curve of the load at the connecting joint of the prefabricated building.

7. A building structure mechanics detection system which adopts the method according to any one of claims 1 to 6 to detect building structure mechanics, characterized in that, Pre-installed acoustic sensors on the surface of the prefabricated building connecting joint component, and instant impact waves are excited on the surface of the building. The impact waves propagate in the concrete medium of the prefabricated building and are reflected into the acoustic sensors. The system includes: A collection module for collecting the time-domain waveform of the reflected echo in the acoustic sensor; A processing module for marking the concrete structure of the prefabricated building as a plurality of detection units, and then extracting the drift feature of the propagation of the reflected echo in the concrete medium from the time-domain waveform through the time delay characteristics of the stress wave propagation path in each detection unit, and mapping the drift feature to the grouting saturation of the concrete structure in the prefabricated building according to the mapping relationship between the wave speed of the reflected echo and the grouting state; The processing module is also used to apply a multi-stage cyclic load for non-destructive testing at the connecting joint of the prefabricated building based on the grouting saturation, and to read the displacement information at the connecting joint under the multi-stage cyclic load, and then to extract the inflection point of the hysteresis curve of the load at the connecting joint of the prefabricated building from the displacement information; An execution module for fusion evaluation of the mechanical stability of the connecting joint component of the prefabricated building according to the inflection point of the hysteresis curve of the load and the grouting saturation to obtain the stability grade of the prefabricated building structure mechanics, which specifically includes: Multi-parameter fusion of the inflection point of the hysteresis curve of the load and the grouting saturation to obtain the mechanical stability index of the connecting joint component of the prefabricated building, i.e. converting the grouting saturation to a relative value in the [0, 1] interval, i.e. relative value = grouting saturation / 100%, converting the inflection point load to load retention rate, i.e. load retention rate = inflection point load / design load, and directly using the stiffness ratio as the deterioration index. Based on the analytic hierarchy process, the weight of each parameter is determined, and a nonlinear fusion function is used, i.e. mechanical stability index = 1-exp[-2.5(relative value^0.5×load retention rate^0.3×(2-deterioration index)^0.2)], to calculate the mechanical stability index of the connecting joint component of the prefabricated building; Divide the stability grade of the prefabricated building structure mechanics through the mechanical stability index.

8. A computer device, comprising: The computer device comprises a memory for storing a computer program and a processor for calling and running the computer program from the memory, so that the computer device executes the building structure mechanics detection method in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores instructions or codes, and when the instructions or codes are run on the computer, the computer executes the building structure mechanics detection method in any one of claims 1 to 6.

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