A high-precision monitoring system for cable stress during stable lifting of box beams

Abstract

The present application relates to the field of stress monitoring technology, and specifically to a high-precision monitoring system for steel cable stress during the stable lifting of a box girder, the system comprising: collecting stress data and tilt angle data of each steel cable used to lift the box girder at each collection moment; dividing each axisymmetric steel cable; obtaining stress interference factors at each collection moment; obtaining external force interference moments based on stress interference factors; obtaining weight coefficients and power coefficients of tilt angle data at each external force interference moment; obtaining real stress data at each collection moment; obtaining stress clutter factors at each collection moment, and performing high-precision monitoring of steel cable stress during the stable lifting of a box girder. The present application improves the accuracy of steel cable stress monitoring during the stable lifting of a box girder.

Description

Technical Field

[0001] The present application relates to the technical field of stress monitoring, and in particular to a high-precision monitoring system for steel cable stress during the stable lifting of a box girder. Background Art

[0002] When building a bridge, the box girder needs to be hoisted to the main cable by a cable-mounted crane. During the hoisting process, the stress state of the steel cable, as the main load-bearing component, is directly related to the safety and stability of the hoisting operation. By monitoring the stress changes of the steel cable in real time, potential stress concentration, overload or fatigue damage can be discovered in time, thereby avoiding serious accidents such as steel cable breakage and ensuring the safety of the hoisting operation.

[0003] Common stress monitoring methods include vibration frequency method, resistance strain gauge measurement method, optical fiber strain gauge measurement method and piezoelectric sensor measurement method. Although these methods can monitor the stress of steel cables, their measurement accuracy is limited. When measuring the stress of each steel cable during the box girder hoisting process, the box girder will inevitably be disturbed by external forces, resulting in the stress measurement results of the steel cables not reflecting the true state of the steel cables, which in turn affects the stress monitoring accuracy of the steel cables. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a high-precision monitoring system for cable stress during the stable lifting of box beams. The technical solutions adopted are as follows:

[0005] The present application proposes a high-precision monitoring system for cable stress during stable lifting of a box girder, the system comprising:

[0006] The data acquisition module is used to collect stress data and inclination angle data of each steel cable used to hoist the box girder at each acquisition time;

[0007] A stress clutter factor acquisition module is used to divide each pair of axisymmetric steel cables; based on the difference between the stress data and the mean value of the stress data and the discreteness of the stress data of the axisymmetric steel cables, the stress interference factor at each acquisition moment is acquired; based on the stress interference factor, the external force interference moment is acquired; based on the difference between the stress data and the tilt angle data, the weight coefficient and power coefficient of the tilt angle data at each external force interference moment are acquired; based on the stress data, the tilt angle data and the weight coefficient and power coefficient of the tilt angle data, the real stress data of each steel cable at each acquisition moment is acquired; based on the discreteness of the real stress data and the difference between the real stress data at adjacent acquisition moments, the stress clutter factor at each acquisition moment is acquired;

[0008] The steel cable stress monitoring module is used to monitor the steel cable stress during the stable lifting process of the box girder based on the stress complexity factor.

[0009] Furthermore, the axisymmetric steel cables are two steel cables that are symmetrical with respect to the center of the box girder.

[0010] Furthermore, the method for obtaining the stress interference factor is:

[0011] Calculate the stress and value at each acquisition moment;

[0012] Obtaining axisymmetric stress data of each pair of axisymmetric steel cables based on the stress data;

[0013] The calculation formula of the stress interference factor is: ; In the formula, is the stress interference factor at the i-th acquisition moment; is the sum of stress data of all cables at the i-th acquisition moment, is the mean of the stress and value at the ith acquisition moment and all previous acquisition moments, is the variance of the axisymmetric stress data of all axisymmetric cables at the i-th acquisition moment.

[0014] Furthermore, the method for obtaining the stress sum value is: at each collection moment, the sum of the stress data of all the steel cables is calculated as the stress sum value at each collection moment.

[0015] Furthermore, the method for obtaining the axisymmetric stress data is:

[0016] For each acquisition moment, the sum of the stress data of each pair of axisymmetric steel cables on the box girder is calculated as the axisymmetric stress data of each pair of axisymmetric steel cables at each acquisition moment.

[0017] Furthermore, the method for acquiring the external force interference moment is: taking the collection moment when the stress interference factor is greater than the value 0 as the external force interference moment.

[0018] Furthermore, the weight coefficient and power coefficient of the tilt angle data at each external force interference moment are obtained, including:

[0019] For each external force interference moment, a set of two-variable linear equations of mechanical equilibrium is constructed, and the formula is: ; In the formula, , , are the stress data of the first, second and nth cables at each external force interference moment, , and are the inclination angle data of the i-th, 2-th and n-th cables at each external force interference moment, is the mean of the stress and value at each external force interference moment and all previous acquisition moments, , are the stress data of the axisymmetric cables of the first and second cables at each external force interference moment, , are the inclination angle data of the first and second axisymmetric steel cables at each external force interference moment, a is the weight coefficient of the inclination angle data at each external force interference moment, and b is the power coefficient of the inclination angle data at each external force interference moment;

[0020] The mechanical equilibrium linear equations of two variables are solved together to obtain the weight coefficients and power coefficients of the tilt angle data at each external force interference moment.

[0021] Furthermore, the method for obtaining the real stress data is:

[0022] For each steel cable at each external force interference moment, a calculation result of an exponential function with the tilt angle data as the base and the power coefficient of the tilt angle data as the exponent is calculated, the product of the calculation result and the weight coefficient of the tilt angle data is calculated, and the difference between the stress data and the product is used as the true stress data of each steel cable at each external force interference moment;

[0023] The stress data of the steel cable when the collection time is not disturbed by external forces is taken as the real stress data.

[0024] Furthermore, the calculation formula of the stress disorder factor is: ; is the stress clutter factor at the i-th acquisition moment; is the variance of the true stress data of all cables at the i-th acquisition moment; is the real stress data of the k-th steel cable at the i-th acquisition time; is the true stress data of the kth steel cable at the i-1th moment, and n is the total number of steel cables used to hoist the box girder.

[0025] Furthermore, the high-precision monitoring of the stress of the steel cables during the stable lifting of the box girder includes:

[0026] For the stress chaos factor at each collection moment, when the stress chaos factor is greater than the preset safety threshold, the stress of the steel cable is abnormal during the stable lifting of the box girder; otherwise, the stress of the steel cable is normal during the stable lifting of the box girder.

[0027] This application has at least the following beneficial effects:

[0028] This application aims at the problem that during the box girder hoisting process, the stress data of each steel cable measured by the piezoelectric sensor is interfered by external forces, resulting in inaccurate measurement results, and then inaccurate stress monitoring. A high-precision monitoring system for steel cable stress during the stable hoisting of the box girder is proposed. First, according to whether the stress data of each steel cable conforms to mechanical equilibrium, a stress interference factor is constructed to determine whether the measured stress data is interfered by external forces. When interfered by external forces, each stress data is corrected so that the obtained stress data can more truly reflect the stress state of the steel cable, thereby improving the accuracy of the stress monitoring of the steel cable. Then, not only according to the degree of stress difference between each steel cable, but also according to the change of the stress of each steel cable relative to the previous moment, a stress chaos factor is constructed to monitor whether there is potential danger in the stress state of each steel cable, so that the stress monitoring result of the steel cable is more accurate, thereby improving the accuracy of the stress monitoring of the steel cable during the stable hoisting of the box girder. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A flow chart of a high-precision monitoring system for cable stress during stable lifting of a box girder provided in this application;

[0031] Figure 2 Obtain a flow chart for the stress clutter factor. DETAILED DESCRIPTION

[0032] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation method, structure, features and effects of a high-precision monitoring system for cable stress during the stable lifting of a box girder proposed in the present application are described in detail below in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0033] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0034] The specific scheme of the high-precision monitoring system for cable stress during the stable lifting of a box girder provided by the present application is described in detail below with reference to the accompanying drawings.

[0035] See also Figure 1 , which shows a flow chart of a high-precision monitoring system for steel cable stress during the stable lifting of a box girder provided by an embodiment of the present application. The system includes: a data acquisition module 101, a stress clutter factor acquisition module 102, and a steel cable stress monitoring module 103.

[0036] The data acquisition module 101 collects stress data and tilt angle data of each steel cable used to hoist the box girder at each acquisition time.

[0037] During the hoisting process of the box girder, piezoelectric sensors and inclination sensors are installed on all the steel cables used for hoisting the box girder to obtain the stress data and inclination angle data of each steel cable at each collection time; among them, the collection frequency of the piezoelectric sensor and the inclination sensor is 3Hz, and the implementer can select other values ​​according to the actual situation.

[0038] The stress clutter factor acquisition module 102 divides each pair of axisymmetric steel cables; acquires the stress interference factor at each acquisition moment based on the difference between the stress data and the mean value of the stress data and the discreteness of the stress data of the axisymmetric steel cables; acquires the external force interference moment based on the stress interference factor; acquires the weight coefficient and power coefficient of the inclination angle data at each external force interference moment based on the difference between the stress data and the inclination angle data; acquires the real stress data of each steel cable at each acquisition moment based on the stress data, the inclination angle data and the weight coefficient and power coefficient of the inclination angle data; acquires the stress clutter factor at each acquisition moment based on the discreteness of the real stress data and the difference between the real stress data at adjacent acquisition moments.

[0039] The working principle of the piezoelectric sensor is that when the piezoelectric material is subjected to stress, it will generate charges of opposite signs on two opposite surfaces. The greater the stress, the greater the change in the charge. The change in charge can be used to obtain the change in stress of the steel cable.

[0040] During the box girder hoisting process, the stress state of the steel cable is monitored. When stress concentration and stress mutation are detected, the steel cable should be adjusted in time to ensure the safety of the construction. However, the box girder hoisting is usually located in an open environment and is inevitably disturbed by wind. The wind will cause the box girder to sway slightly. When the box girder sways and the inclination angle of the steel cable increases, the stress on the steel cable will increase, resulting in an increase in the stress measurement of the piezoelectric sensor. However, the stress change of the steel cable caused by the shaking of the box girder is not a problem of the steel cable itself, so in this case, there is no need to adjust the steel cable. In order to eliminate the influence of external interference on the stress data of the steel cable, the measurement results need to be corrected.

[0041] During the box girder hoisting process, the positions of the steel cables in the box girder plane are usually center-symmetrical, and the two steel cables that are center-symmetrical with the box girder are regarded as a stack of axisymmetric steel cables.

[0042] In the absence of external interference, the forces on each cable during the lifting process of the box girder are in a state of mechanical equilibrium. Regardless of whether it is tilted or not, the sum of the forces on each cable is constant; when the box girder is in a stable lifting process, the stresses on each cable are very close; when the box girder is tilted, the force on the cable above the box girder increases, and the force on the cable in the opposite direction decreases, then the stresses of the two centrally symmetrical cables will increase and decrease, and the sum of the stresses of each axisymmetric cable is very close. When the box girder shakes, the cause of the shaking may be the interference of wind force or the uneven force on the cable of the box girder itself. Therefore, it is necessary to judge the cause of the shaking of the box girder. When the box girder shakes due to wind force, the lifting process of the box girder is disturbed by external forces and is no longer in a state of mechanical equilibrium; when the shaking is caused by uneven stress of the cable, the lifting process of the box girder is not disturbed by external forces and is in a state of mechanical equilibrium.

[0043] According to the above analysis, for each acquisition moment, the sum of the stress data of all steel cables is calculated as the stress sum value at each acquisition moment, and the sum of the stress data of each pair of axisymmetric steel cables on the box girder is calculated as the axisymmetric stress data of each pair of axisymmetric steel cables at each acquisition moment. Furthermore, in order to reflect the degree of interference of the stress data by external forces, the stress interference factor at each acquisition moment is obtained based on the average situation of the stress sum value and the discrete degree of the axisymmetric stress data. The calculation formula is: ; In the formula, is the stress interference factor at the i-th acquisition moment; is the sum of stress data of all cables at the i-th acquisition moment, is the mean of the stress and value at the ith acquisition moment and all previous acquisition moments, is the variance of the axisymmetric stress data of all axisymmetric cables at the i-th acquisition moment.

[0044] It should be noted that when The larger the value of is, the greater the difference between the sum of stress at the i-th acquisition moment and the average value of the sum of stress at the previous i moments is, which further indicates that the piezoelectric sensor at the i-th acquisition moment is subjected to greater external force interference. The larger the value is, the greater the difference in the sum of the stresses of the axisymmetric steel cables at the i-th acquisition moment is, which further indicates that the piezoelectric sensor is subjected to greater external force interference at the i-th acquisition moment.

[0045] Furthermore, when the stress interference factor at the i-th acquisition moment is greater than the value 0, the i-th acquisition moment is regarded as the external force interference moment; when the stress interference factor at the i-th acquisition moment is equal to the value 0, it means that the i-th acquisition moment is not interfered by external forces.

[0046] When the i-th acquisition moment is the moment of external force interference, the stress data measured at the i-th acquisition moment has external interference and cannot accurately reflect the actual stress of the steel cable, so the data needs to be corrected. When the piezoelectric sensor is tilted, the size of the stress data will change with the size of the inclination angle of the steel cable. The larger the inclination angle, the larger the stress data measured by the piezoelectric sensor. The error of the stress data caused by external force interference is positively correlated with the inclination angle. The stress data can be subtracted from the error of the stress data due to the external force interference factor to obtain the corrected stress data. At the same time, according to the mechanical equilibrium relationship, the stress data on each axisymmetric steel cable is the same.

[0047] Therefore, based on the above analysis, for each external force interference moment, a set of two-variable linear equations of mechanical equilibrium is constructed, and the formula is: ; In the formula, , , are the stress data of the first, second and nth cables at each external force interference moment, , and are the inclination angle data of the i-th, 2-th and n-th cables at each external force interference moment, is the mean of the stress and value at each external force interference moment and all previous acquisition moments, , are the stress data of the axisymmetric cables of the first and second cables at each external force interference moment, , They are the inclination angle data of the axially symmetrical steel cables of the first and second steel cables at each external force interference moment, a is the weight coefficient of the inclination angle data at each external force interference moment, and b is the power coefficient of the inclination angle data at each external force interference moment.

[0048] The mechanical equilibrium linear equations of two variables are solved together to calculate the weight coefficient and power coefficient of the tilt angle data at each external force interference moment.

[0049] It should be noted that for each external force interference moment, This represents the data after the stress data of the first piezoelectric sensor is corrected. Similarly, add up all the corrected stress data. Then, in the state of mechanical equilibrium, the sum of the stress data should be equal to the average value of the total stress at all acquisition times before the moment of external force interference, and the sum of the stress of the corrected axisymmetric steel cable should be equal to the sum of the stress of other corrected axisymmetric steel cables.

[0050] Furthermore, for each external force interference moment, based on the stress data, the tilt angle data and the weight coefficient and power coefficient of the tilt angle data, the real stress data of each steel cable at each external force interference moment is obtained, and the calculation formula is: ; In the formula, Indicates the real stress data of each steel cable at each external force interference moment; is the stress data of each steel cable at each external force interference moment; It represents the inclination angle data of each steel cable at each external force interference moment; a is the weight coefficient of the inclination angle data at each external force interference moment, and b is the power coefficient of the inclination angle data at each external force interference moment.

[0051] At this point, the real stress data of each steel cable at each external force interference moment is obtained.

[0052] When the acquisition time is not a time of external force interference, the stress data measured at the acquisition time is relatively accurate, so there is no need to correct the stress data, and the stress data at the acquisition time is taken as the real stress data.

[0053] At this point, the real stress data of each steel cable at all acquisition times are obtained.

[0054] Furthermore, in order to reflect the degree of inconsistency of stress of each steel cable during box girder hoisting, the stress chaos factor at each acquisition moment is obtained based on the discrete degree of the real stress data and the difference between the real stress data at adjacent acquisition moments. The calculation formula is: ; is the stress clutter factor at the i-th acquisition moment; is the variance of the true stress data of all cables at the i-th acquisition moment; is the real stress data of the k-th steel cable at the i-th acquisition time; is the true stress data of the kth steel cable at the i-1th moment, and n is the total number of steel cables used to hoist the box girder.

[0055] It should be noted that The larger the value of , the greater the difference in the true stress of each steel cable at the i-th acquisition moment, which further indicates that the degree of inconsistency of the stress of each steel cable is greater; The larger the value, the greater the difference between the real stress data of the kth steel cable at the i-th acquisition moment and the real stress data at the previous moment, which further indicates that the degree of inconsistency of the stress of each steel cable is greater. At this time, the value of the obtained stress chaos factor is larger; conversely, the value of the obtained stress chaos factor is smaller. Among them, the stress chaos factor acquisition flow chart is as follows Figure 2 shown.

[0056] At this point, the stress complexity factor at each acquisition moment is obtained.

[0057] The cable stress monitoring module 103 monitors the cable stress during the stable lifting of the box girder based on the stress chaos factor.

[0058] For the stress chaos factor at each collection moment, when the stress chaos factor is greater than the preset safety threshold, it means that the inconsistency of the stress of each steel cable at the current moment will threaten the construction safety. At this time, the stress of the steel cable is abnormal during the stable lifting of the box girder, and an alarm is issued to promptly remind the engineer to adjust the box girder lifting plan to ensure construction safety; on the contrary, the stress of the steel cable is normal during the stable lifting of the box girder. In this embodiment, the value of the preset safety threshold is 2, and the implementer can select other values ​​according to actual conditions.

[0059] The various embodiments in the present application are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0060] It should be noted that, unless otherwise specified and limited, terms such as "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, an element defined by the sentence "including one..." does not exclude the existence of other identical elements in the article or device including the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items.

[0061] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not invented by the present application.

[0062] It should be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A high-precision monitoring system for cable stress during stable lifting of box beams, characterized in that: The system includes the following modules: The data acquisition module is used to collect stress data and inclination angle data of each steel cable used to hoist the box girder at each acquisition time; The stress clutter factor acquisition module is used to divide each pair of axisymmetric steel cables; based on the difference between the stress data and the mean value of the stress data and the discrete degree of the stress data of the axisymmetric steel cables, the stress interference factor at each acquisition moment is acquired; Obtain the external force interference moment based on the stress interference factor; obtain the weight coefficient and power coefficient of the tilt angle data at each external force interference moment based on the difference between the stress data and the tilt angle data; Based on the stress data, the tilt angle data and the weight coefficient and power coefficient of the tilt angle data, the real stress data of each steel cable at each acquisition time is obtained; Based on the discrete degree of the real stress data and the difference between the real stress data at adjacent acquisition moments, the stress clutter factor at each acquisition moment is obtained; The cable stress monitoring module is used to monitor the cable stress during the stable lifting of the box girder based on the stress chaos factor; The method for obtaining the stress interference factor is: Calculate the stress and value at each acquisition moment; Obtaining axisymmetric stress data of each pair of axisymmetric steel cables based on the stress data; The calculation formula of the stress interference factor is: ; In the formula, is the stress interference factor at the i-th acquisition moment; is the sum of stress data of all cables at the i-th acquisition moment, is the mean of the stress and value at the ith acquisition moment and all previous acquisition moments, is the variance of the axisymmetric stress data of all axisymmetric cables at the i-th acquisition moment; The calculation formula of the stress disorder factor is: ; is the stress clutter factor at the i-th acquisition moment; is the variance of the true stress data of all cables at the i-th acquisition moment; is the real stress data of the k-th steel cable at the i-th acquisition time; is the true stress data of the kth steel cable at the i-1th moment, and n is the total number of steel cables used to hoist the box girder.

2. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The axisymmetric steel cables are two steel cables that are symmetrical with the center of the box beam.

3. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The method for acquiring the stress sum value is: at each collection moment, the sum of the stress data of all the steel cables is calculated as the stress sum value at each collection moment.

4. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The method for obtaining the axisymmetric stress data is: For each acquisition moment, the sum of the stress data of each pair of axisymmetric steel cables on the box girder is calculated as the axisymmetric stress data of each pair of axisymmetric steel cables at each acquisition moment.

5. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The method for acquiring the external force interference moment is: taking the collection moment when the stress interference factor is greater than the value 0 as the external force interference moment.

6. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The weight coefficient and power coefficient of the tilt angle data at each external force interference moment are obtained, including: For each external force interference moment, a set of two-variable linear equations of mechanical equilibrium is constructed, and the formula is: ; In the formula, , , are the stress data of the first, second and nth cables at each external force interference moment, , and are the inclination angle data of the i-th, 2-th and n-th cables at each external force interference moment, is the mean of the stress and value at each external force interference moment and all previous acquisition moments, , are the stress data of the axisymmetric cables of the first and second cables at each external force interference moment, , are the inclination angle data of the first and second axisymmetric steel cables at each external force interference moment, a is the weight coefficient of the inclination angle data at each external force interference moment, and b is the power coefficient of the inclination angle data at each external force interference moment; The mechanical equilibrium linear equations of two variables are solved together to obtain the weight coefficients and power coefficients of the tilt angle data at each external force interference moment.

7. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The method for obtaining the real stress data is: For each steel cable at each external force interference moment, a calculation result of an exponential function with the tilt angle data as the base and the power coefficient of the tilt angle data as the exponent is calculated, the product of the calculation result and the weight coefficient of the tilt angle data is calculated, and the difference between the stress data and the product is used as the true stress data of each steel cable at each external force interference moment; The stress data of the steel cable when the collection time is not disturbed by external forces is taken as the real stress data.

8. A high-precision monitoring system for cable stress during stable lifting of a box girder as claimed in claim 1, characterized in that: The high-precision monitoring of the cable stress during the stable lifting of the box girder includes: For the stress chaos factor at each collection moment, when the stress chaos factor is greater than the preset safety threshold, the stress of the steel cable is abnormal during the stable lifting of the box girder; otherwise, the stress of the steel cable is normal during the stable lifting of the box girder.

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