Intelligent screw and inhaul cable force intelligent monitoring method

Abstract

The invention relates to an intelligent screw and an intelligent inhaul cable force monitoring method, the intelligent screw comprises a screw body, the screw body comprises a polished rod section and two threaded sections, the two threaded sections are arranged at the two ends of the polished rod section respectively, one end is used for being connected with an inhaul cable anchorage device, and the other end is used for being connected with an inhaul cable; the plurality of vibrating wire type sensors are uniformly distributed on the periphery of the polished rod section along the axial direction of the screw rod body and are used for converting axial strain generated by the cable force of the stay cable on the screw rod body into a frequency signal of a steel wire and outputting the frequency signal; the resistance type temperature detection assembly is fixedly installed on the surface of the polished rod section and used for measuring the temperature change of the screw body in real time and converting the temperature change into a resistance signal to be output; and the data acquisition and processing device is in signal connection with the plurality of vibrating wire sensors and the resistance-type temperature detection assembly. Real-time sensing and compensation of temperature change are achieved through the integrated resistance type temperature detection assembly, interference of temperature fluctuation on a measurement result can be accurately eliminated, and therefore accurate measurement of the cable force in the service process of the inhaul cable is achieved.

Description

Technical Field

[0001] This invention relates to the field of cable structure safety monitoring technology, specifically to a smart screw and a smart method for monitoring cable force. Background Technology

[0002] Cable-stayed structures are widely used in infrastructure such as bridges, large public stadiums, and port terminals. The stability and safety of their cable forces directly affect the load-bearing capacity and service life of the entire structure. Currently, cable force monitoring mainly uses external monitoring devices, where sensors are independently installed on the outside of the cable or anchorage. However, this traditional monitoring method has many drawbacks: First, installation is complex, requiring additional support structures, which compromises the integrity of the original cable structure and is costly. Second, the force transmission path is not direct, with force transmission losses between the sensor and the cable, resulting in measurement data that cannot accurately reflect the actual cable force. Third, it has poor anti-interference capabilities; humidity, dust, electromagnetic interference, and temperature changes in outdoor environments can easily affect the stability of the sensors and reduce measurement accuracy.

[0003] Therefore, under this background, without changing the original function of the connecting screw, there is an urgent need to develop a smart screw that can monitor cable force. This connecting screw can be widely used in bridges, public venues, ports and docks, etc., to solve the problems of complex installation, inaccurate measurement and insufficient protection of existing cable force monitoring devices, and fill the technological gap of integrated and highly reliable cable force monitoring equipment. Summary of the Invention

[0004] To address the shortcomings of existing cable tension monitoring devices, this invention provides a smart screw and a smart cable tension monitoring method, which integrates the design of the sensing structure and the screw bearing structure, simplifies the installation process, improves measurement accuracy and environmental adaptability, and ensures the reliability and stability of cable structure safety monitoring.

[0005] The technical solution of the present invention is as follows:

[0006] This invention proposes a smart screw, comprising:

[0007] The screw body includes a smooth section and two threaded sections. The two threaded sections are respectively located at both ends of the smooth section, and one threaded section is used to connect to the cable anchor, while the other threaded section is used to connect to the cable.

[0008] Multiple vibrating wire sensors are evenly distributed along the axial direction of the screw body on the outer periphery of the polished rod section, used to convert the axial strain of the screw body caused by the cable force into the frequency signal output of the steel wire;

[0009] A resistance temperature detection component is fixedly installed on the surface of the optical rod section, used to measure the temperature change of the screw body in real time and convert it into a resistance signal output.

[0010] The data acquisition and processing device is connected to multiple vibrating wire sensors and resistive temperature detection components to synchronously acquire the frequency signal and resistance signal, and to perform temperature compensation correction on the strain corresponding to the frequency signal based on the resistance signal, and to calculate the actual value of the cable force through the corrected strain.

[0011] In some embodiments, the smooth section of the screw body and the two threaded sections are coaxially arranged and integrally connected to form a cylindrical structure.

[0012] In some embodiments, the number of vibrating wire sensors is four, and the four vibrating wire sensors are distributed at 90° intervals in the circumferential direction of the optical rod section, and the extension direction of the steel wire of the vibrating wire sensor is parallel to the axis of the screw body.

[0013] In some embodiments, a radially penetrating elongated mounting hole is provided on the optical rod segment, and the vibrating wire sensor is doubly fixed in the mounting hole by structural adhesive and positioning screws.

[0014] In some embodiments, the smart screw further includes a sleeve, which is fitted and fixed to the outside of the optical rod segment for covering the plurality of the vibrating wire sensors and the resistive temperature detection assembly.

[0015] In some embodiments, the smart screw further includes an output end aviation plug, which is mounted on the sleeve and connected to multiple vibrating wire sensors and the resistive temperature detection component via wires, for centralized transmission of frequency signals output by multiple vibrating wire sensors and resistance signals output by the resistive temperature detection component.

[0016] In some embodiments, the data acquisition and processing device includes a signal acquisition module and a data processing module, wherein the signal acquisition module is used to synchronously acquire the frequency signal and the resistance signal, and the data processing module has a built-in cable force calculation model, which is used to calculate the actual value of the cable force based on the strain corresponding to the frequency signal after temperature compensation correction according to the resistance signal.

[0017] In some embodiments, the corrected strain is calculated as follows:

[0018]

[0019] In the formula, ε represents the actual strain of the screw body after temperature correction caused by the cable force, K represents the calibration coefficient of the vibrating wire sensor, and f iThis represents the frequency of the steel wire output by each vibrating wire sensor under the action of cable force; f0 represents the initial reference frequency of each vibrating wire sensor; n represents the number of vibrating wire sensors; and K represents the frequency of the steel wire. T R represents the temperature correction factor. T R0 represents the initial resistance of the resistive temperature sensing component under the action of cable force, and α represents the equivalent temperature coefficient of the resistive temperature sensing component.

[0020] In some embodiments, the actual value of the cable force is calculated as follows:

[0021]

[0022] In the formula, F represents the actual value of the cable force, E represents the elastic modulus of the screw body, r represents the radius of the smooth section, K represents the calibration coefficient of the vibrating wire sensor, and f i This represents the frequency of the steel wire output by each vibrating wire sensor under the action of cable force; f0 represents the initial reference frequency of each vibrating wire sensor; n represents the number of vibrating wire sensors; and K represents the frequency of the steel wire. T R represents the temperature correction factor. T R0 represents the initial resistance of the resistive temperature sensing component under the action of cable force, and α represents the equivalent temperature coefficient of the resistive temperature sensing component.

[0023] This invention also proposes a method for intelligent monitoring of cable force based on the above-mentioned intelligent screw, comprising the following steps:

[0024] Install the smart screw: Tightly connect the threaded sections at both ends of the screw body to the corresponding cable anchor and cable;

[0025] Reference parameter calibration: Before the cable force is applied, the data acquisition and processing device acquires and stores the initial reference frequency f0 of each vibrating wire sensor and the initial resistance value R0 of the resistive temperature detection component through the signal acquisition module.

[0026] Real-time signal acquisition: After the cable force is applied, the data acquisition and processing device synchronously acquires the steel wire frequency f output by each vibrating wire sensor under the cable force through the signal acquisition module. i And the resistance value R output by the resistance temperature sensing component under the action of cable force. T ;

[0027] Cable Force Calculation Output: The data acquisition and processing device automatically calculates the actual cable force using the cable force calculation model built into the data processing module. .

[0028] The advantages of this invention compared to existing technologies are as follows: This invention provides a smart screw and a smart cable force monitoring method. This smart screw achieves high-precision, anti-interference, and long-term stable cable force monitoring through multiple vibrating wire sensors, a resistance temperature detection component, and a data acquisition and processing device. Specifically, it has at least the following practical effects:

[0029] In this invention, the smart screw integrates multiple vibrating wire sensors and resistive temperature detection components with the screw body, eliminating the need for additional monitoring brackets. This makes installation convenient and does not disrupt the original cable force transmission path, reducing construction difficulty and cost.

[0030] In this invention, the smart screw is completely identical to the ordinary screw in terms of geometric dimensions, connection method, and load-bearing path. It can be directly replaced without affecting the original structural construction process and load-bearing function, thus realizing the "seamless integration" of monitoring functions into building components.

[0031] In this invention, multiple vibrating wire sensors are arranged on the outside of the screw body. The steel wire material of the vibrating wire sensor has stable properties and is not prone to creep and relaxation, making it suitable for long-term monitoring.

[0032] In this invention, a multi-directional vibrating wire sensor is used to collect strain signals. The frequency signal output by the sensor has the advantages of accurate measurement and strong anti-interference ability, which can reduce errors in the signal transmission process. At the same time, combined with the temperature compensation of the resistive temperature detection component, the influence of temperature change on the measurement results can be effectively eliminated. Combined with the elimination of errors caused by uneven local stress, the accuracy of cable force measurement is significantly improved.

[0033] In this invention, the sleeve can effectively protect the screw body, vibrating wire sensor, and resistive temperature detection component from interference from external environments such as mechanical impact, moisture, and corrosion. It can be adapted to complex and harsh outdoor environments, ensuring long-term stable operation of the device.

[0034] In this invention, the output aviation plug can effectively transmit monitoring data to the data acquisition and processing device.

[0035] In this invention, the data acquisition and processing device achieves automated acquisition, calculation and output without manual intervention, thus reducing operation and maintenance costs.

[0036] In this invention, the geometric parameters of the smart screw are adjustable, making it suitable for cables of different diameters. It can be widely used in safety monitoring scenarios for various cable structures such as bridges, large stadiums, and port terminals.

[0037] It should be understood that the description in the Summary of the Invention is not intended to limit the key or essential features of the embodiments of the present invention, nor is it intended to restrict the scope of the invention. Other features of the invention will become readily apparent from the following description. Furthermore, implementation of any embodiment of the present invention does not imply the simultaneous possession or achievement of multiple or all of the aforementioned beneficial effects. Attached Figure Description

[0038] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0039] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0040] Figure 1 This is a schematic diagram of a smart screw structure capable of monitoring cable force according to some embodiments of the present invention;

[0041] Figure 2 This is a simplified installation diagram of four vibrating wire sensors according to a specific embodiment of the present invention.

[0042] Marked in the image:

[0043] 1-Screw body; 101-Smooth section; 102-Threaded section;

[0044] 2-Vibrating wire sensor;

[0045] 3-Resistance temperature sensing component;

[0046] 4-Sleeve;

[0047] 5-Output terminal aviation connector.

[0048] The same or corresponding marks in the diagram indicate the same or corresponding parts. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] It should be understood that the terms "comprising / including," "consisting of," or any other variations are intended to cover non-exclusive inclusion, such that a product, apparatus, process, or method that comprises a list of elements includes not only those elements but may also include, where necessary, other elements not expressly listed, or elements inherent to such a product, apparatus, process, or method. Without further limitation, an element defined by the phrases "comprising / including," "consisting of," does not exclude the presence of additional identical elements in the product, apparatus, process, or method that includes said element.

[0052] It should also be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device, component or structure referred to must have a specific orientation, be constructed or operated in a specific orientation, and should not be construed as a limitation of the present invention.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0054] The implementation of the present invention will be described in detail below with reference to preferred embodiments.

[0055] like Figures 1 to 2 As shown, the present invention proposes a smart screw that can monitor the cable force. The smart screw includes a screw body 1, a vibrating wire sensor 2, a resistance temperature detection component 3, and a data acquisition and processing device.

[0056] The screw body 1 includes a smooth section 101 and two threaded sections 102, wherein the two threaded sections 102 are respectively provided at both ends of the smooth section 101, and the threaded section 102 at one end of the smooth section 101 is used to connect the cable anchor, and the threaded section 102 at the other end of the smooth section 101 is used to connect the cable.

[0057] In some embodiments, the smooth rod section 101 and the two threaded sections 102 of the screw body 1 are coaxially arranged and integrally connected cylindrical structures to provide space for sensor installation without weakening the load-bearing capacity.

[0058] In this invention, the integrally molded screw body structure has strong integrity and high mechanical strength, which can adapt to the working conditions of long-term cable bearing and extend the service life of the smart screw.

[0059] In this invention, the screw body 1 can be made of Q355b steel or other structural steel with good elastic modulus stability.

[0060] In this invention, to achieve accurate identification of the axial strain of the screw due to the cable axial force, multiple vibrating wire sensors 2 are provided, which are evenly distributed along the axial direction of the screw body 1 on the outer periphery of the smooth section 101. When the smart screw is subjected to force, the screw body 1 experiences axial strain, which in turn causes the steel wires in the multiple vibrating wire sensors 2 to experience axial strain. This is used to measure the change in the frequency of the steel wires, thereby converting the axial strain of the screw body 1 caused by the cable force into a frequency signal output from the steel wires.

[0061] In this invention, the number of vibrating wire sensors 2 can be flexibly selected as two, three, four or more according to the actual monitoring accuracy requirements, and the specific number is not limited.

[0062] In this invention, the advantage of setting multiple vibrating wire sensors 2 is that a redundant monitoring structure can be formed, which has excellent fault tolerance and robustness. Even if individual sensors fail or even malfunction due to long-term fatigue, external force damage or environmental corrosion, the other normally functioning sensors can still continuously collect the axial strain data of the screw, ensuring that the cable force monitoring system is uninterrupted and does not fail.

[0063] See Figure 2 The number of vibrating wire sensors 2 is preferably four. The four vibrating wire sensors 2 are distributed at 90° intervals in the circumferential direction of the smooth rod section 101, and the extension direction of the steel wire of each vibrating wire sensor 2 is parallel to the axis of the screw body 1.

[0064] In this embodiment, the 90° equally spaced circular distribution pattern enables full circumferential strain coverage of the smooth rod segment 101, allowing for simultaneous acquisition of axial strain data from different orientations of the screw body 1. This effectively avoids biased strain acquisition caused by localized stress concentration or force offset in the screw, ensuring that the data accurately reflects the overall stress state of the screw. Simultaneously, the extension direction of the steel string is parallel to the screw axis, guaranteeing that the strain direction of the steel string is completely consistent with the axial strain direction of the screw. This avoids strain transmission losses caused by angular deviations and ensures a precise correspondence between the steel string frequency change and the screw's axial strain.

[0065] As is easy to understand, the vibrating wire sensor 2 is a conventional vibrating wire strain sensing structure, mainly composed of a steel wire, exciter, vibration pickup and signal conditioning unit. All components are existing mature technologies, and the function of converting strain to frequency signals can be realized without additional modifications.

[0066] In some embodiments, a radially penetrating elongated mounting hole (not shown in the figure) is provided on the optical rod section 101. The hole diameter is determined according to the external dimensions of the vibrating wire sensor 2 used. The hole wall is polished and surface treated to avoid stress concentration interfering with strain transmission.

[0067] The vibrating wire sensor 2 is fixed in the mounting hole by both structural adhesive and positioning screws. During installation, the direction of the steel wire of the vibrating wire sensor 2 must be strictly parallel to the axis of the screw body 1 to ensure that the axial strain energy generated under stress is transmitted to the steel wire without attenuation.

[0068] In this invention, a dual fixing method using structural adhesive and positioning screws is adopted, which can achieve a tight fit between the vibrating wire sensor 2 and the wall of the mounting hole. This not only prevents the sensor from loosening due to vibration and impact, but also ensures that the axial strain of the screw body 1 is transmitted to the sensor steel wire without loss. This is the preferred fixing method of this invention.

[0069] In addition, the vibrating wire sensor 2 can also be fixed in other equivalent ways that are easily conceived by those skilled in the art, such as fixing by welding, clamping, threaded fastener locking, or magnetic attraction. The core design concept of all the above-mentioned fixing methods is to achieve a firm connection between the vibrating wire sensor 2 and the screw body 1, ensuring that the axial strain of the screw can be stably transmitted to the sensor steel wire. These equivalent fixing methods all fall within the protection scope of this invention.

[0070] In addition, after installation, the steel wire of each vibrating wire sensor 2 needs to be subjected to initial tension to reach the initial reference frequency f0 specified by the manufacturer. After installation, calibration data is collected using a data acquisition and processing device to establish a database of initial reference frequencies f0 for multiple vibrating wire sensors 2.

[0071] The resistance temperature detection component 3 is fixedly installed on the surface of the smooth rod section 101. Its function is to eliminate the interference of temperature fluctuation on the measurement accuracy during the real-time measurement of cable force by the vibrating wire sensor 2 on the screw body 1.

[0072] Specifically, the resistance temperature detection component 3 is used to collect the temperature change of the screw body 1 in real time and convert the temperature change into a corresponding resistance value signal output, providing accurate temperature data support for subsequent temperature compensation and correction.

[0073] In some embodiments, the resistance temperature sensing component 3 is fixed to the outer surface of the guide rod section 101 with structural adhesive to accurately reflect the temperature of the screw body 1. The selection of the resistance temperature sensing component 3 meets the requirements of high sensitivity, low hysteresis, and long-term stability.

[0074] In addition, the resistive temperature sensing component 3 can also be fixed in other equivalent ways that are easy for those skilled in the art to conceive of, such as welding, as long as the resistive temperature sensing component 3 can be tightly attached to the outer surface of the optical rod section 101 to ensure the stable and accurate transmission of the temperature signal.

[0075] It should be noted that the resistive temperature sensing component 3 used in this invention is a conventional temperature-sensitive element. Its specific structure includes, but is not limited to, temperature sensing elements known to those skilled in the art, such as thermistors, platinum resistance thermometers, and metal film resistance temperature sensors. The structure of the resistive temperature sensing component 3 and the temperature-resistance signal conversion principle are existing mature technologies, and no additional structural modifications are required to meet the temperature acquisition requirements of this invention.

[0076] The data acquisition and processing device is connected to multiple vibrating wire sensors 2 and resistive temperature detection components 3 to synchronously acquire the frequency signals output by the vibrating wire sensors 2 and the resistance signals output by the resistive temperature detection components 3. The data acquisition and processing device can perform temperature compensation correction on the strain corresponding to the frequency signal based on the resistance signal, and calculate the actual value of the cable force using the corrected strain.

[0077] In some embodiments, the data acquisition and processing device includes a signal acquisition module and a data processing module. The signal acquisition module is used to synchronously acquire the frequency signal output by the vibrating wire sensor 2 and the resistance signal output by the resistive temperature detection component 3. The data processing module has a built-in cable force calculation model. It is used to receive the frequency signal output by the vibrating wire sensor 2 and the resistance signal output by the resistive temperature detection component 3 transmitted by the signal acquisition module, and to perform temperature compensation correction on the strain corresponding to the frequency signal output by the vibrating wire sensor 2 according to the resistance signal output by the resistive temperature detection component 3, and to calculate the actual value of the cable force through the corrected strain.

[0078] In this embodiment, the corrected strain is calculated as follows:

[0079]

[0080] In the formula, ε represents the actual strain of the screw body after temperature correction caused by the cable force, K represents the calibration coefficient of the vibrating wire sensor 2, and f i The frequency of the steel wire output by each vibrating wire sensor 2 under the action of cable force is represented by f0, the initial reference frequency of each vibrating wire sensor 2 is represented by n, and the number of vibrating wire sensors 2 is represented by K. T R represents the temperature correction factor. T R0 represents the initial resistance of the resistance temperature sensing component 3 under the action of the cable force, and α represents the equivalent temperature coefficient of the resistance temperature sensing component 3.

[0081] In this embodiment, the actual value of the cable force is calculated as follows:

[0082]

[0083] In the formula, F represents the actual value of the cable force, E represents the elastic modulus of the screw body, r represents the radius of the smooth section, K represents the calibration coefficient of the vibrating wire sensor 2, and f i The frequency of the steel wire output by each vibrating wire sensor 2 under the action of cable force is represented by f0, the initial reference frequency of each vibrating wire sensor 2 is represented by n, and the number of vibrating wire sensors 2 is represented by K. T R represents the temperature correction factor. T R0 represents the initial resistance of the resistance temperature sensing component 3 under the action of the cable force, and α represents the equivalent temperature coefficient of the resistance temperature sensing component 3.

[0084] In this invention, the cable force calculation model built into the data processing module corresponds precisely to the calculation formula for the actual value of the cable force mentioned above. After the data acquisition and processing device synchronously acquires the frequency output of the vibrating wire sensor 2 and the resistance value output of the resistive temperature detection component 3, it calculates the cable force based on the built-in structural parameters, such as the initial reference frequency f0 of each vibrating wire sensor 2, the initial resistance value R0 of the resistive temperature detection component 3, the elastic modulus E of the screw body, the radius r of the smooth section, the calibration coefficient K of the vibrating wire sensor 2, the number n of the vibrating wire sensors 2, and the temperature correction coefficient K. T The equivalent temperature coefficient α of the resistance temperature sensing component 3 can be directly obtained from this built-in formula (the actual value of the cable force). The calculation formula is automatically output, and the actual value of the cable force is automatically generated without the need for additional manual calculation, thus realizing the automation and intelligence of cable force monitoring.

[0085] It should be noted that the data acquisition and processing device has excellent fault tolerance performance. When any one or more of the multiple vibrating wire sensors 2 are damaged and cannot output effective frequency signals, the device can automatically identify and discard the invalid signals of the failed sensors, and only collect the frequency change signals output by the remaining normal sensors. Then, following the same temperature compensation correction and cable force calculation process as described above, the actual value of the cable force can be accurately calculated, realizing the function that the damage of a single or partial sensor does not affect the overall cable force monitoring and calculation.

[0086] In this invention, the derivation of the above-mentioned modified strain calculation and the actual value of the cable force calculation is as follows:

[0087] A conventional vibrating wire sensor 2 mainly consists of a steel wire, an excitation coil, and a pickup coil, and is arranged as a whole on the smooth section 101 of the screw body 1. When the screw body 1 is not subjected to cable force and does not produce strain, that is, when the structure is undeformed, the steel wire of the vibrating wire sensor 2 is in a specific initial tension state, corresponding to an initial reference frequency f0. When the smart screw is subjected to cable force and produces strain, the overall structure deforms, causing the tension of the steel wire inside the vibrating wire sensor to change.

[0088] According to the vibration formula of transverse waves in a steel string, the natural frequency of the steel string, that is, the frequency of the steel string under the action of cable force for the vibrating wire sensor 2, is calculated by the following formula:

[0089]

[0090] In the formula, f N The value represents the frequency of the steel string of each vibrating wire sensor 2 under the action of cable force, without considering temperature changes. N represents the tension in the steel string of the vibrating wire sensor 2 under the action of cable force. L represents the effective length of the steel string. ρ represents the linear density of the steel string. A represents the cross-sectional area of ​​the steel string.

[0091] Transforming the above formula yields:

[0092]

[0093] In the formula, f0 represents the initial reference frequency of each vibrating wire sensor 2, that is, the initial frequency of the steel wire output by the vibrating wire sensor 2 before the cable force is applied, and N0 represents the initial tension in the steel wire, that is, the initial tension in the steel wire before the cable force is applied by the vibrating wire sensor 2. f represents the magnitude of the change in tension within the steel string of the vibrating wire sensor 2 under the action of cable force. N This represents the frequency of the steel string of each vibrating wire sensor 2 under the action of cable force, without considering temperature changes.

[0094] From the above formula, it can be seen that the tension within the steel wire is proportional to the square of the frequency of the steel wire in the vibrating wire sensor 2. Since the vibrating wire sensor 2 is installed on the smooth rod section 101, that is, the steel wire is fixed to the screw body 1, when the screw body 1 is subjected to the cable force and generates strain, the overall structure deforms, and the tension within the steel wire changes accordingly. According to the principles of mechanics of materials, the tension within the steel wire is proportional to the strain, therefore the following relationship can be obtained:

[0095]

[0096] In the formula, The value represents the strain caused by the change in cable force at the location of each vibrating wire sensor 2 on the optical rod segment 101. K represents the calibration coefficient of the vibrating wire sensor 2, which is determined by pre-calibration or testing before leaving the factory.

[0097] Due to the different materials of the steel wire and the screw body in the vibrating wire sensor 2, they have different coefficients of thermal expansion, resulting in inconsistent deformation when the temperature changes. Therefore, it is necessary to introduce additional temperature strain. The actual strain after temperature correction at the location of each vibrating wire sensor 2 on the screw body 1 is as follows:

[0098]

[0099] In the formula, Δ(f T 2 f represents the squared change in the frequency of the steel string of each vibrating wire sensor 2 caused by temperature. i This indicates the magnitude of the steel string frequency output by each vibrating wire sensor 2 under the action of cable force (i.e., the measured frequency of the steel string of each vibrating wire sensor 2 under the action of cable force, taking into account temperature changes).

[0100] Since the temperature change is proportional to the square of the frequency change of the steel string, that is... Where β represents the influence coefficient of temperature on the square of frequency. The true strain after temperature correction at the location of each vibrating wire sensor 2 on the screw body 1 is as follows:

[0101] .

[0102] Since the screw body 1 is equipped with multiple vibrating wire sensors 2, the actual strain of the smart screw after temperature correction caused by the cable force can be transformed into:

[0103]

[0104] make Then the above formula can be written as:

[0105]

[0106] In the formula, ε represents the actual strain of the screw body 1 after temperature correction caused by the cable force, K represents the calibration coefficient of the vibrating wire sensor 2, and f i The frequency of the steel wire output by each vibrating wire sensor 2 under the action of cable force is represented by f0, the initial reference frequency of each vibrating wire sensor 2 is represented by n, and the number of vibrating wire sensors 2 is represented by K. T The temperature correction coefficient is determined by pre-calibration or testing before the vibrating wire sensor 2 leaves the factory. T represents the temperature of the screw body 1 when the frequency of the steel wire is read after the cable applies the cable force, and T0 represents the temperature of the screw body 1 before the cable applies the cable force.

[0107] Unlike ordinary resistance strain gauges, the resistance change of the resistance-type temperature sensing component 3 is primarily driven by temperature changes. Its response to the mechanical strain generated by the coordinated deformation of the structure is significantly lower than its corresponding temperature response. Therefore, it can serve as a reliable temperature input for the temperature correction term of the vibrating wire sensor 2. The relationship between its resistance and temperature is as follows:

[0108]

[0109] In the formula, R T R0 represents the resistance value of the resistance temperature detection component read after the cable is subjected to cable force, that is, the resistance value output by the resistance temperature detection component 3 under the action of cable force. R0 represents the resistance value of the resistance temperature detection component read before the cable is subjected to cable force, that is, the initial resistance value of the resistance temperature detection component 3. α represents the equivalent temperature coefficient of the resistance temperature detection component 3, which is determined by pre-calibration before leaving the factory.

[0110] Therefore, the calculation of the true strain of the screw body 1 after temperature correction caused by the cable force is as follows:

[0111]

[0112] Furthermore, according to the principles of mechanics of materials, the intelligent screw under the action of cable force F has the following relationship with strain:

[0113]

[0114] In the formula, ε represents the axial strain of the smart screw, i.e., the screw body 1, caused by the cable force, E represents the elastic modulus of the screw body material, and r represents the radius of the smooth section 101 of the screw body 1.

[0115] Since the resistance temperature sensing component 3 is used to measure the actual temperature change of the screw body 1, the measured temperature is converted and used as the uniform input for the temperature correction term of the vibrating wire sensor 2. This temperature correction term is used to eliminate the equivalent additional strain caused by the thermal expansion mismatch between the vibrating wire and its base and the screw body.

[0116] Therefore, the actual value F of the cable force is calculated as follows:

[0117]

[0118] Compared to traditional external cable force monitoring devices, the intelligent screw of this invention integrates a vibrating wire sensor, a resistance temperature detection component, and the screw body into a single unit. This retains the screw's inherent force transmission and connection function while allowing the vibrating wire sensor to directly capture the axial strain of the screw body caused by the cable force and convert it into a steel wire frequency signal output. Simultaneously, the resistance temperature detection component measures the temperature change of the screw body in real time and converts it into a resistance value signal output. The data acquisition and processing device simultaneously acquires the aforementioned frequency and resistance signals, and performs temperature compensation correction on the strain corresponding to the frequency signal based on the resistance value signal. This effectively eliminates the interference of environmental temperature fluctuations on the measurement, ultimately achieving long-term accurate monitoring of cable force during cable service.

[0119] See also Figure 1 The smart screw also includes a sleeve 4, which is fitted and fixed to the outside of the smooth rod section 101 to cover multiple vibrating wire sensors 2 and resistance temperature detection components 3.

[0120] The sleeve 4 is made of corrosion-resistant alloy steel or stainless steel, with enough space inside to accommodate multiple vibrating wire sensors 2 and resistance temperature detection components 3.

[0121] In some embodiments, the sleeve 4 is welded or threaded to the outside of the polished rod section 101.

[0122] Furthermore, the smart screw also includes an output end aviation plug 5, which is mounted on the sleeve 4 and connected to multiple vibrating wire sensors 2 and resistive temperature detection components 3 via wires. This is used to centrally transmit the frequency output by the multiple vibrating wire sensors 2 and the resistance value output by the resistive temperature detection components 3.

[0123] In one embodiment, the resistive temperature sensing component 3 and four vibrating wire sensors 2 are connected to the output terminal aviation plug 5 to form a complete temperature-strain coupling measurement system.

[0124] More specifically, an output aviation plug 5 is provided on the outside of the sleeve 4. The output aviation plug 5 is fixed by a sealing insulating ring and has IP67 protection performance, which can withstand the effects of humid, dusty, and rainy environments. The vibrating wire sensor 2 and the resistance temperature detection component 3 are connected to the output aviation plug 5 through shielded wires to enhance anti-interference capability.

[0125] The data acquisition and processing device is connected to the screw body 1 via the output aviation plug 5. It can collect the frequency output of each vibrating wire sensor 2 and the resistance value output of the resistive temperature detection component 3 in real time, so as to realize the automatic conversion and calculation of cable force.

[0126] This invention also proposes a method for intelligent monitoring of cable force based on the above-mentioned intelligent screw, comprising the following steps:

[0127] Install the smart screw and fasten the threaded sections 102 at both ends of the screw body 1 to the corresponding cable anchor and cable respectively;

[0128] Before applying cable force, the data acquisition and processing device collects and stores the initial reference frequency f0 of each vibrating wire sensor 2 and the initial resistance value R0 of the resistive temperature detection component 3 through the signal acquisition module, as the reference parameters for subsequent cable force calculation.

[0129] Real-time signal acquisition: After the cable force is applied, the data acquisition and processing device synchronously acquires the steel string frequency f output by each vibrating wire sensor 2 under the action of the cable force through the signal acquisition module. i And the resistance R output by the resistive temperature sensing component 3 under the action of the cable force. T ;

[0130] The cable force calculation output shows that the data acquisition and processing device automatically calculates the actual value of the cable force through the cable force calculation model built into the data processing module.

[0131] As is easily understood, the cable force calculation model here is the same as the formula used to calculate the actual value of the cable force mentioned above. The data processing module can directly call this built-in formula and automatically output the actual value of the cable force without additional manual intervention, thus realizing the automation and intelligence of cable force monitoring.

[0132] In one specific embodiment, taking a smart screw equipped with four vibrating wire sensors 2 as an example, the smart cable force monitoring method using this smart screw is as follows:

[0133] First, replace the original screw in the cable structure with the screw body 1. That is, fasten the screw body 1 to the cable and anchor respectively through the threaded sections 102 at both ends of the screw body 1, so that the force transmission mode of the original structure is not changed in the force path. Then connect the output aviation plug 5 to the external data acquisition and processing device.

[0134] Before the cable is subjected to force, the signal acquisition module of the data acquisition and processing device acquires the initial reference frequency f0 of the four vibrating wire sensors 2 and the initial resistance value R0 of the resistive temperature detection component 3. The data is automatically used for measurement formula calibration.

[0135] After the cable force is applied, the signal acquisition module of the data acquisition and processing device acquires the steel wire frequencies f1, f2, f3, and f4 output by the vibrating wire sensor 2 under the cable force, as well as the resistance value R of the resistance temperature detection component 3. T .

[0136] The data acquisition and processing device automatically calculates the actual value of the cable force using the cable force calculation model built into the data processing module, i.e., the following formula:

[0137]

[0138] The intelligent screw of this invention achieves real-time sensing and compensation of temperature changes by integrating a vibrating wire sensor and a resistive temperature detection component. This accurately eliminates the interference of temperature fluctuations on measurement results, thereby enabling precise determination of cable force during cable service. Furthermore, the intelligent screw of this invention offers advantages such as convenient installation, strong anti-interference capabilities, and good environmental adaptability, making it widely applicable to safety monitoring scenarios for various cable structures, including bridges, public venues, and port terminals.

[0139] It will be readily understood by those skilled in the art that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0140] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A smart screw, characterized in that, include: The screw body includes a smooth section and two threaded sections. The two threaded sections are respectively located at both ends of the smooth section, and one threaded section is used to connect to the cable anchor, while the other threaded section is used to connect to the cable. Multiple vibrating wire sensors are evenly distributed along the axial direction of the screw body on the outer periphery of the polished rod section, used to convert the axial strain of the screw body caused by the cable force into the frequency signal output of the steel wire; A resistance temperature detection component is fixedly installed on the surface of the optical rod section, used to measure the temperature change of the screw body in real time and convert it into a resistance signal output. The data acquisition and processing device is connected to multiple vibrating wire sensors and resistive temperature detection components to synchronously acquire the frequency signal and resistance signal, and to perform temperature compensation correction on the strain corresponding to the frequency signal based on the resistance signal, and to calculate the actual value of the cable force through the corrected strain.

2. The smart screw according to claim 1, characterized in that, The smooth section of the screw body and the two threaded sections are coaxially arranged and integrally connected to form a cylindrical structure.

3. The smart screw according to claim 1, characterized in that, The number of vibrating wire sensors is four, and the four vibrating wire sensors are distributed at 90° intervals in the circumferential direction of the optical rod section, and the extension direction of the steel wire of the vibrating wire sensor is parallel to the axis of the screw body.

4. The smart screw according to claim 1, characterized in that, The optical rod section has a radially penetrating elongated mounting hole, and the vibrating wire sensor is fixed in the mounting hole by both structural adhesive and positioning screws.

5. The smart screw according to claim 1, characterized in that, The smart screw also includes a sleeve, which is fitted and fixed to the outside of the smooth rod section to cover multiple vibrating wire sensors and the resistive temperature detection assembly.

6. The smart screw according to claim 5, characterized in that, The smart screw also includes an output end aviation plug, which is mounted on the sleeve and connected to multiple vibrating wire sensors and the resistive temperature detection component via wires, for centralized transmission of frequency signals output by multiple vibrating wire sensors and resistance signals output by the resistive temperature detection component.

7. The smart screw according to claim 1, characterized in that, The data acquisition and processing device includes a signal acquisition module and a data processing module. The signal acquisition module is used to simultaneously acquire the frequency signal and the resistance signal. The data processing module has a built-in cable force calculation model, which is used to calculate the actual value of the cable force based on the strain corresponding to the frequency signal after temperature compensation correction according to the resistance signal.

8. The smart screw according to claim 1, characterized in that, The corrected strain is calculated as follows: In the formula, ε represents the real strain of the screw body after temperature correction caused by the cable force, K represents the calibration coefficient of the vibrating wire sensor, f i represents the steel wire frequency output by each vibrating wire sensor under the action of the cable force, f0 represents the initial reference frequency of each vibrating wire sensor, n represents the number of vibrating wire sensors, K T represents the temperature correction coefficient, R T represents the resistance value output by the resistance temperature detection component under the action of the cable force, R0 represents the initial resistance value of the resistance temperature detection component, and α represents the equivalent temperature coefficient of the resistance temperature detection component.

9. The smart screw according to claim 8, characterized in that, The actual value of the cable force is calculated as follows: In the formula, F represents the actual value of the cable force, E represents the elastic modulus of the screw body, r represents the radius of the smooth section, K represents the calibration coefficient of the vibrating wire sensor, and f i This represents the frequency of the steel wire output by each vibrating wire sensor under the action of cable force; f0 represents the initial reference frequency of each vibrating wire sensor; n represents the number of vibrating wire sensors; and K represents the frequency of the steel wire. T R represents the temperature correction factor. T R0 represents the initial resistance of the resistive temperature sensing component under the action of cable force, and α represents the equivalent temperature coefficient of the resistive temperature sensing component.

10. A method for intelligent monitoring of cable force based on the intelligent screw according to any one of claims 1 to 9, characterized in that, Includes the following steps: Install the smart screw: Tightly connect the threaded sections at both ends of the screw body to the corresponding cable anchor and cable; Reference parameter calibration: Before the cable force is applied, the data acquisition and processing device acquires and stores the initial reference frequency f0 of each vibrating wire sensor and the initial resistance value R0 of the resistive temperature detection component through the signal acquisition module. Real-time signal acquisition: After the cable force is applied, the data acquisition and processing device synchronously acquires the steel wire frequency f output by each vibrating wire sensor under the cable force through the signal acquisition module. i And the resistance value R output by the resistance temperature sensing component under the action of cable force. T ; Cable Force Calculation Output: The data acquisition and processing device automatically calculates the actual cable force value through the cable force calculation model built into the data processing module. .

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