A tower crane safety monitoring method and system based on digital twinning

Abstract

The application belongs to the field of engineering safety monitoring, and provides a tower crane safety monitoring method and system based on digital twinning, comprising: constructing a geometric model of a tower crane by using modeling software; constructing a physical model of the tower crane based on the geometric model and physical properties of the tower crane; acquiring real-time operation data of the tower crane; calculating stress of a key position of the tower crane according to the operation data and the physical model, and organizing the stress into a stress time sequence; calculating cumulative fatigue of the key position according to the stress time sequence; and performing a safety warning if the cumulative fatigue of the key position exceeds a preset value. The above scheme efficiently performs tower crane safety monitoring.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of engineering safety monitoring, and specifically relates to a tower crane safety monitoring method and system based on digital twinning. BACKGROUND

[0002] A tower crane (referred to as a tower crane) is an important mechanical equipment used in construction, and its main function is to lift and transport heavy objects through vertical and horizontal movement. Since the tower crane usually operates at high altitudes and in complex working conditions, its structural safety is crucial. In order to ensure the safe operation of the tower crane, the traditional detection and maintenance method mainly relies on periodic manual inspection and maintenance.

[0003] At present, many tower cranes obtain monitoring data in real time by installing high-precision sensors. The data obtained by these sensors can help operators and engineers understand the operating status of the tower crane in real time and provide early warning for some sudden abnormal situations. However, such technology has significant limitations, that is, it can only monitor physical characteristic data and cannot directly obtain the fatigue condition of the tower crane. SUMMARY

[0004] In order to solve the problems in the prior art, the present application provides a tower crane safety monitoring method based on digital twinning, which comprises the following steps: constructing a geometric model of the tower crane using modeling software; constructing a physical model of the tower crane based on the geometric model and physical properties of the tower crane; obtaining real-time operating data of the tower crane; calculating the stress of the key position of the tower crane according to the operating data and the physical model, and organizing the stress into a stress time sequence; calculating the cumulative fatigue of the key position according to the stress time sequence; and performing a safety warning if the cumulative fatigue of the key position exceeds a preset value.

[0005] Another aspect of the present application also provides a tower crane safety monitoring system based on digital twinning, which comprises the following modules:

[0006] A geometric modeling module for constructing a geometric model of the tower crane using modeling software;

[0007] A physical modeling module for constructing a physical model of the tower crane based on the geometric model and physical properties of the tower crane;

[0008] A data acquisition module for obtaining real-time operating data of the tower crane;

[0009] A calculation module for calculating the stress of the key position of the tower crane according to the operating data and the physical model, and organizing the stress into a stress time sequence;

[0010] A counting module for calculating the cumulative fatigue of the key position according to the stress time sequence;

[0011] An early warning module is configured to issue a safety warning if the accumulated fatigue of the critical position exceeds a preset value.

[0012] The present application has the following beneficial effects:

[0013] Real-time monitoring and analysis of the tower crane through digital twin technology can significantly improve the safety and efficiency of the tower crane. The algorithm used in the present application can improve the accuracy of stress cycle recognition and fatigue life prediction, providing a scientific and reliable technical means for the structural health monitoring and maintenance of the tower crane. This not only helps to identify potential fatigue damage risks in advance, but also provides a scientific basis for maintenance and repair work, ensuring the safe operation of the tower crane under complex working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0014] 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 in the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0015] Figure 1 is a flowchart of the method of the present application. DETAILED DESCRIPTION

[0016] The preferred description of the present application will be made below in combination with the drawings and specific embodiments.

[0017] This embodiment solves the above technical problems by the following steps:

[0018] In one embodiment, with reference to Figure 1 The present application provides a tower crane safety monitoring method based on digital twin.

[0019] Constructing a geometric model of the tower crane is one of the basic steps of the application of digital twin technology. Through the accurate establishment of the geometric model, reliable data support can be provided for subsequent physical modeling, stress analysis and fatigue analysis.

[0020] First, obtain detailed design drawings and technical materials from the tower crane manufacturer or design team. These materials can include detailed information such as the size, shape, material, connection method, etc. of each component of the tower crane.

[0021] Select appropriate computer-aided design (CAD) software to construct the geometric model, such as SolidWorks, AutoCAD, CATIA, Creo, etc.

[0022] In the modeling software, according to the design drawings and technical data, gradually build the geometric model of the tower crane. According to the design drawings of the tower crane, first create the basic shape of each component of the tower crane. Including:

[0023] Tower body: usually composed of steel structure high tower, can be generated by stretching and rotating the basic shape.

[0024] Jib: usually long strip-shaped steel structure, can be generated by stretching and Boolean operation.

[0025] Slewing bearing: usually disc-shaped support structure, can be generated by rotating.

[0026] After creating the basic shape, add detailed features such as connecting holes, stiffeners, welds, etc. Combine each component together to form a complete tower crane model.

[0027] Further, simplify the geometric shape without affecting the analysis accuracy, reduce the amount of calculation.

[0028] Building a physical model of the tower crane is a key step in structural analysis and dynamic monitoring. The physical model combines the geometric shape and material properties of the tower crane, which can accurately simulate the mechanical behavior of the tower crane under various loads and working conditions.

[0029] First, collect the physical properties and material parameters of each component of the tower crane. These parameters usually include the density, elastic modulus, Poisson's ratio, yield strength, etc. of the material.

[0030] Import the tower crane geometric model built in the previous step into the finite element analysis software (such as ANSYS, Abaqus). The geometric model contains each component of the tower crane and its connection relationship.

[0031] In order to carry out finite element analysis, the geometric model needs to be meshed. Meshing is to discretize the continuous geometric model into a finite number of elements for numerical calculation.

[0032] According to the structural characteristics of the tower crane, select the appropriate mesh type. For example, you can choose tetrahedral elements or hexahedral elements for meshing.

[0033] Set the size and density of the mesh to ensure calculation accuracy and efficiency. Generally, key parts such as connecting holes and stress concentration areas require finer mesh, while non-critical areas can use coarser mesh.

[0034] In the finite element analysis software, according to the physical properties and material parameters collected in the previous step, assign the corresponding material properties to each component of the geometric model.

[0035] Create a material library in the finite element analysis software and input the density, elastic modulus, Poisson's ratio and yield strength parameters of the material.

[0036] Assign material properties from the material library to individual components of the geometric model. For example, assign steel material properties to the tower body and the jib.

[0037] Further, to simulate the mechanical behavior of the tower crane under actual working conditions, loads and boundary conditions need to be applied in the physical model.

[0038] Define the static loads of the tower crane during operation, such as self-weight, hoisted load, etc. These loads can be realized by applying gravity and concentrated forces.

[0039] Define the dynamic loads of the tower crane under dynamic working conditions, such as wind load, seismic load, etc. These loads can be realized by applying periodic forces and transient forces.

[0040] Define the boundary conditions of the tower crane, such as the fixed support at the bottom of the tower. These boundary conditions can be realized by constraining displacement and rotation.

[0041] Based on the geometric model and physical properties of the tower crane, a physical model is constructed, providing a reliable data foundation for subsequent stress analysis and fatigue analysis. The accuracy and completeness of the physical model directly affect the application effect of digital twin technology, ensuring the comprehensiveness and reliability of the tower crane safety monitoring.

[0042] Real-time acquisition of tower crane operation data is a key step to ensure dynamic updating of the tower crane digital twin model and accurate reflection of actual working conditions. Through high-precision sensors and advanced communication technology, various operating parameters of the tower crane can be monitored in real time, and these data can be transmitted to the central system for processing and analysis.

[0043] Operating data includes:

[0044] Self-weight load: the impact of the tower crane's own weight on the structure.

[0045] Hoisting load: the load borne by the tower crane when hoisting heavy objects.

[0046] Swing arm displacement: swing and displacement of the jib.

[0047] Tower body inclination displacement: inclination and displacement of the tower body due to load and wind force, etc.

[0048] Rotary displacement: rotational displacement of the rotary support part of the tower crane.

[0049] Wind speed and direction: the impact of wind speed and direction on the tower crane structure.

[0050] In the structural analysis and safety monitoring of the tower crane, the stress of the key positions refers to those parts of the tower crane structure that are prone to stress concentration, deformation or damage. The stress state of these key positions is directly related to the safety and operational stability of the tower crane.

[0051] Specifically includes:

[0052] Tower bottom stress, the tower bottom is the main position of the tower crane to bear the dead weight and lifting load. Due to the height and gravity position of the tower crane, the tower bottom often bears the maximum compressive stress and shear stress. Specifically:

[0053] Compressive stress: due to the dead weight of the tower and the weight of the lifting load, the tower bottom bears a large axial compressive stress. Divide the total load by the cross-sectional area of the tower bottom to get the compressive stress of the tower bottom.

[0054] Shear stress: wind load and lateral force caused by rotation will produce shear stress at the tower bottom. The wind load and lateral force caused by rotation can be calculated, and the lateral force is divided by the cross-sectional area of the tower bottom to get the shear stress of the tower bottom.

[0055] Jib root stress, the jib root connects the tower and the jib, and is the force transmission point of the jib swing and lifting load, which is prone to stress concentration and fatigue failure. Specifically:

[0056] Bending stress: due to the dead weight of the jib and the lifting load, the jib root bears a large bending stress. Calculate the bending moment of the jib dead weight and lifting load at the jib root, and divide the bending moment by the cross-sectional modulus to get the bending stress of the jib root.

[0057] Shear stress: lateral force caused by swing and rotation will produce shear stress at the jib root. Calculate the lateral force caused by swing and rotation, and divide the lateral force by the cross-sectional area to get the shear stress of the jib root.

[0058] Rotary bearing stress, rotary bearing is the key component of the rotating part of the tower crane, bearing the weight of the upper structure of the tower crane and the dynamic load during rotation. Specifically:

[0059] Contact stress: due to the weight and rotation load borne by the rotary bearing, high contact stress will be generated. Calculate the total load borne by the rotary bearing, including the weight of the upper structure of the tower crane and the rotation load, and get the contact area of the rotary bearing through the geometric model, and divide the total load by the contact area to get the contact stress of the rotary bearing.

[0060] Bending stress and shear stress: due to the rotary motion and lateral force, bending stress and shear stress will be generated in the rotary bearing. Calculate the bending moment generated by the rotary motion and the shear force caused by the lateral force, and get the cross-sectional modulus and cross-sectional area of the rotary bearing through the geometric model, and divide the bending moment by the cross-sectional modulus to get the bending stress, and divide the shear force by the cross-sectional area to get the shear stress.

[0061] Hook and sling connection stress, the hook and sling connection is the connection point of the tower crane and the lifting load, bearing the total weight of the load and the dynamic impact load. Specifically:

[0062] Tensile stress: due to the weight of the hoisted object, the hook and the sling connection are subjected to tensile stress. Calculate the total weight of the hoisted object, obtain the cross-sectional area of the hook and sling connection through the geometric model, divide the load by the cross-sectional area to obtain the tensile stress of the hook and sling connection.

[0063] Impact stress: dynamic load and impact force during hoisting can cause impact stress at the connection.

[0064] Support leg and foundation stress, support leg and foundation are important guarantee of tower crane stability, bear the overall weight of the tower crane and external load. Specifically:

[0065] Compression stress and shear stress: due to the weight of the tower crane and external load, the support leg and foundation will produce compression stress and shear stress.

[0066] Bending stress: lateral force caused by wind load and seismic load will produce bending stress in the support leg and foundation. Calculate the lateral force caused by wind load and seismic load. Calculate the bending moment produced by the lateral force acting on the support leg and foundation. Divide the bending moment by the cross-sectional modulus to obtain the bending stress.

[0067] During the operation of the twin model, by periodically obtaining the operation data of the tower crane, and combining these data with the physical model, the stress of each key position can be calculated in real time, and then the stress time series data of these key positions can be obtained.

[0068] In the previous step, the stress time series data of the key positions were obtained, and in this step, the stress cycles were further identified and the cumulative fatigue was calculated.

[0069] For each key position, obtain its stress time series data, which records the stress values at different time points.

[0070] σ(t)={σ(t1),σ(t2),...,σ(t n )}

[0071] Where σ(t i ) represents the stress value at time t i .

[0072] In order to extract the main features of the stress signal and reduce the influence of noise, wavelet transform is used to perform multi-scale analysis on the stress time series, specifically:

[0073] Select the mother wavelet function (Morlet wavelet or Daubechies wavelet can be used),

[0074] Perform wavelet transform to obtain the representation of the stress signal at different scales:

[0075]

[0076] where W σ (a,b) are the wavelet transform coefficients of the stress σ(t) at scale and location, φ(a,b) is the mother wavelet function.

[0077] To consider the dynamic characteristics of stress changes, the stress amplitude is dynamically adjusted to more accurately reflect the stress changes under actual working conditions. The dynamic stress range adjustment is:

[0078] σ a,adj = σ a ·(1+α·Δt)

[0079] where σ a,adj is the adjusted stress amplitude, σ a is the original stress amplitude (which can be calculated by half of the maximum and minimum amplitude of each stress cycle), α is the adjustment coefficient, and Δt is the adjustment time interval (which can be determined according to actual data experiments).

[0080] According to the statistical characteristics of the stress time series, the counting threshold is dynamically adjusted:

[0081] σ threshold = μ+k·σ

[0082] where μ is the mean of the stress time series, σ is the standard deviation, and k is the adjustment coefficient.

[0083] Using the dynamically adjusted stress amplitude and threshold, stress cycles are identified and counted:

[0084] a. Initial screening: Extract all local extrema (peaks and valleys) from the stress time series.

[0085] b. Threshold application: Filter out significant stress ranges according to the dynamic threshold value, excluding changes less than the threshold value.

[0086] c. Cycle pairing: Apply the rainflow counting method rule to pair the peak-valley pairs that meet the standard into stress cycles.

[0087] d. Counting record: Record the amplitude and occurrence frequency of each cycle.

[0088] Combined with the fatigue characteristics of the material and the actual working conditions, the stress-life (S-N) curve is corrected, and the fatigue life of each stress amplitude is calculated:

[0089]

[0090] where N i is the fatigue life corresponding to the i-th stress amplitude, σ′ f is the fatigue strength coefficient of the material, B is the fatigue strength index, and σa,adj,i is the adjusted stress amplitude, and f(T, H) is a correction function for environmental factors such as temperature and humidity.

[0091] Using the Miner linear cumulative damage theory, the total damage is calculated, and the cumulative damage is the sum of the damage of all stress cycles, that is, the cumulative fatigue

[0092]

[0093] where n i is the number of cycles of the i-th stress amplitude, N i is the fatigue life corresponding to the i-th stress amplitude, and k is the total number of stress amplitudes.

[0094] According to the design standards, use specifications and relevant industry standards of the tower crane, the safety threshold of cumulative fatigue damage is determined. Generally, when the cumulative fatigue damage reaches or exceeds 1, it indicates that the structure may be damaged by fatigue, and maintenance or replacement is required. The twin model monitors the key positions with cumulative fatigue values close to the safety threshold in real time and takes timely maintenance measures.

[0095] Through detailed cumulative fatigue calculation and evaluation methods, the safety of each key position and the whole of the tower crane can be scientifically evaluated. This not only helps to discover potential fatigue damage risks in advance, but also provides a scientific basis for maintenance and repair work, ensuring the safe operation of the tower crane under complex working conditions.

[0096] On the other hand, the present application also provides a tower crane safety monitoring system based on digital twinning, comprising:

[0097] A geometric modeling module for constructing a geometric model of the tower crane using modeling software;

[0098] A physical modeling module for constructing a physical model of the tower crane based on the geometric model and physical properties of the tower crane;

[0099] A data acquisition module for acquiring real-time operation data of the tower crane;

[0100] A calculation module for calculating the stress of the key position of the tower crane according to the operation data and the physical model, and organizing the stress into a stress time sequence;

[0101] A counting module for calculating the cumulative fatigue of the key position according to the stress time sequence;

[0102] An early warning module for performing safety warning if the cumulative fatigue of the key position exceeds a preset value.

[0103] Further, the specific implementation method of the tower crane safety monitoring system based on digital twinning is the same as the tower crane safety monitoring method based on digital twinning, and all the further technical solutions in the tower crane safety monitoring method based on digital twinning are completely introduced into the tower crane safety monitoring system based on digital twinning.

[0104] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced by the equivalent, without departing from the spirit and scope of the present application, any modification or equivalent replacement should be covered within the protection scope of the claims of the present application.

[0105] The part of the module structure of the present application is not particularly clear, and the content of the prior art is used as the standard. The prior art mentioned in the foregoing background section and the specific embodiment section of the present application can be used as a part of the present application to understand the meaning of some technical features or parameters. The protection scope of the present application is subject to the content actually recorded in the claims.

Claims

1. A tower crane safety monitoring method based on digital twinning, characterized by The method comprises the following steps: constructing a geometric model of the tower crane using modeling software; constructing a physical model of the tower crane based on the geometric model and physical properties of the tower crane; obtaining real-time operation data of the tower crane; calculating stress at key positions of the tower crane according to the operation data and the physical model, and organizing the stress into a stress time series; the key positions include a tower bottom, a boom root, a slewing bearing, a hook and sling connection, a support leg, and a foundation; calculating cumulative fatigue of the key positions according to the stress time series; if the cumulative fatigue of the key positions exceeds a preset value, performing a safety warning; calculating cumulative fatigue of the key positions according to the stress time series comprises: for each key position, obtaining its stress time series data; performing multi-scale analysis on the stress time series using wavelet transform, performing wavelet transform to obtain representations of the stress signal at different scales: wherein is the stress at the scale and position of the wavelet transform coefficient, is the mother wavelet function; dynamically adjusting the stress amplitude and adjusting the dynamic stress range: wherein is the adjusted stress amplitude, is the original stress amplitude, a is the adjustment factor, and Δt is the adjustment time interval. dynamically adjusting the counting threshold according to the statistical characteristics of the stress time series: ； wherein μ is the mean of the stress time series, σ is the standard deviation, and k is the adjustment coefficient; using the dynamically adjusted stress amplitude and threshold to identify stress cycles and count: extracting all local extrema from the stress time series; filtering out significant stress ranges according to the dynamic threshold value, excluding changes less than the threshold value; applying rainflow counting rules to pair peak-valley pairs that meet the standard into stress cycles; recording the amplitude and occurrence frequency of each cycle; combining the fatigue characteristics of the material and the actual working conditions to correct the stress-life curve and calculate the fatigue life of each stress amplitude: wherein, N is the fatigue life of the material, is the fatigue strength coefficient of the material, and B is the fatigue strength exponent, is the adjusted stress amplitude, is a correction function for temperature and humidity environmental factors; using the Miner linear cumulative damage theory to calculate the cumulative fatigue.

2. The tower crane safety monitoring method based on digital twinning according to claim 1, characterized in that The operation data of the tower crane at least includes self-weight load, hoisting load, swing arm displacement, tower body inclination displacement, slewing displacement, wind speed, and wind direction.

3. A tower crane safety monitoring system based on digital twinning, the system implementing the method of claim 1, characterized in that The system comprises the following modules: a geometric modeling module for constructing a geometric model of the tower crane using modeling software; a physical modeling module for constructing a physical model of the tower crane based on the geometric model and physical properties of the tower crane; a data acquisition module for obtaining real-time operation data of the tower crane; a calculation module for calculating stress at key positions of the tower crane according to the operation data and the physical model, and organizing the stress into a stress time series; a counting module for calculating cumulative fatigue of the key positions according to the stress time series; the key positions include a tower bottom, a boom root, a slewing bearing, a hook and sling connection, a support leg, and a foundation; a warning module for performing a safety warning if the cumulative fatigue of the key positions exceeds a preset value.

4. The tower crane safety monitoring system based on digital twinning of claim 3, wherein The operation data of the tower crane at least includes self-weight load, hoisting load, swing arm displacement, tower body inclination displacement, slewing displacement, wind speed, and wind direction.

5. The tower crane safety monitoring system based on digital twinning of claim 4, wherein According to the use of the dynamically adjusted stress amplitude and threshold to identify stress cycles and perform rainflow counting, it comprises: a. extracting all local extrema from the stress time series; b. filtering out significant stress ranges according to the dynamic threshold value, excluding changes less than the threshold value; c. Apply the rainflow counting rule to pair the peak-valley pairs that meet the criteria into stress cycles; d. Record the amplitude and occurrence number of each cycle.

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