A strain-adaptive transmission tower tie plate system and method of use

Abstract

This invention relates to a strain-adaptive transmission tower connecting plate system and its control method. The system includes: a connecting plate structure comprising a plate-shaped substrate and grooves disposed on the plate-shaped substrate, wherein multiple adjustable screws are installed on two opposite groove walls; a mesh structure formed by shape memory alloy wires interlaced above the grooves via rings at the top of multiple adjustable screws; a stress sensing module for real-time acquisition of dynamic strain data of the grooves; a temperature control module for adjusting the current and voltage of the shape memory alloy wires to control their temperature; and a control module, connected to both the stress sensing module and the temperature control module, for adjusting the operating temperature of the shape memory alloy based on the received dynamic strain data to generate corresponding expansion and contraction deformation, thereby counteracting the dynamic strain experienced by the connecting plate structure. This invention can control fatigue cracks in the connecting plates caused by wind-induced vibration of transmission towers at specific locations and enables rapid replacement of intelligent metal materials.

Description

Technical Field

[0001] This invention relates to the field of transmission tower operation and maintenance technology, specifically to a strain-adaptive transmission tower connecting plate system and a method for replacing related components. Background Technology

[0002] As a core connecting component in the transmission tower structure, the connecting plate can efficiently bear various external loads borne by the tower—including wind loads and icing loads caused by the natural environment, tension generated by conductor operation, and the self-weight of the component itself. Through optimized structural design, these loads are smoothly transferred from a single load-bearing component to multiple connected tower components, achieving reasonable guidance and even distribution of force flow, and effectively avoiding overload of local components. At the same time, through precise dimensional matching and rigid connection design, the connecting plate firmly fixes the relative spatial position and connection angle of the various components of the tower, constructing and maintaining the geometric invariant system of the entire tower, ensuring the stability and integrity of the complex spatial structure. It is an indispensable key connecting element in the complex spatial structure of transmission towers.

[0003] However, during long-term service, the connecting plates must continuously withstand dynamic alternating loads caused by wind vibration and conductor galloping, which easily leads to cumulative fatigue damage. In addition, stress concentration phenomena that are difficult to completely avoid during the design phase, microscopic defects in materials that may remain from the manufacturing process (such as microcracks and inclusions), and the corrosive effects of harsh outdoor operating environments (such as high humidity, salt spray, and industrial corrosive media) all contribute to the gradual decline in the mechanical properties of the connecting plate material. Furthermore, initial microcracks are prone to develop in stress concentration areas. These microcracks continue to expand with prolonged service time and cyclic loading, ultimately causing a significant decrease in the load-bearing capacity of the connecting plate, seriously threatening the overall structural safety of the transmission tower, and potentially even leading to major safety accidents such as tower instability and collapse. Therefore, timely detection, identification, and replacement of cracked connecting plates is a necessary and crucial measure to eliminate safety hazards at the source, ensure the structural integrity of transmission line towers, and ultimately maintain the safe and stable operation of the power grid.

[0004] Existing technologies for replacing transmission tower connectors have three major drawbacks: First, they pose high safety risks, as workers face significant physical exertion from prolonged high-altitude work, increasing the risk of falls. Second, they are technically challenging, with the conductor load transfer process being complex and requiring extremely high precision, heavily reliant on skilled personnel and specialized tools. Third, they are costly, involving substantial manpower and specialized equipment, and are severely constrained by weather and terrain conditions; power outages result in power loss, while live-line work carries even higher risks and costs. These factors collectively limit the efficiency and safety of replacement operations. Summary of the Invention

[0005] To address the safety hazards such as structural instability of transmission towers caused by cracks in the connecting plates, this invention proposes a strain-adaptive transmission tower connecting plate system and its control method. This system makes the occurrence of cracks in the connecting plates precisely controllable and allows for timely intervention, thereby ensuring the safe operation of the transmission tower.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: According to a first aspect of the present invention, a strain-adaptive transmission tower coupling system is provided. The strain-adaptive transmission tower coupling system includes: A connecting plate structure includes a plate-shaped base and a groove provided on the plate-shaped base, wherein multiple adjustable screws are installed on two opposite groove walls of the groove; The mesh structure is formed by shape memory alloy wires being interlaced and connected above the grooves through the nail rings at the top of the plurality of adjustable screws; A stress sensing module is used to collect dynamic strain data of the groove in real time; A temperature control module is used to adjust the current and voltage of the shape memory alloy wire to control its temperature. The control module, connected to the stress sensing module and the temperature control module respectively, is used to adjust the working temperature of the shape memory alloy based on the received dynamic strain data to generate corresponding expansion and contraction deformation, so as to counteract the dynamic strain on the connecting plate structure.

[0007] Furthermore, the shape memory alloy exhibits the characteristic of a reversible phase transformation between martensite and austenite phases.

[0008] Furthermore, a heat insulation layer is laid above the groove of the connecting plate structure to reduce the interference of the external ambient temperature on the working temperature of the shape memory alloy.

[0009] Furthermore, the stress sensing module includes multiple distributed strain sensors deployed at the bottom of the groove.

[0010] According to a second aspect of the present invention, a control method for a strain-adaptive transmission tower coupling system according to the first aspect of the present invention is provided. The method includes the following steps: Based on the dynamic strain data, the effective fatigue strain components are obtained; Determine the safety threshold, warning threshold, and limit threshold; The effective fatigue strain component is compared with the safety threshold, warning threshold, and limit threshold. Based on the comparison results, a temperature control command is sent to the temperature control module.

[0011] Furthermore, determine the safety threshold, warning threshold, and limit threshold, including: Determine the corresponding initial values ​​for the safety threshold, warning threshold, and limit threshold; The real-time current and voltage data of the shape memory alloy wire are obtained through the temperature control module, thereby obtaining the real-time relative resistance change rate of the shape memory alloy wire. Based on the relative rate of change of resistance and the preset resistance-stiffness mapping coefficient, the equivalent elastic modulus attenuation coefficient of the shape memory alloy wire is obtained. Record temperature control commands, obtain the cumulative number of thermal cycles of the shape memory alloy wire based on the recorded historical temperature control commands, and obtain the cumulative damage degree based on the cumulative number of thermal cycles and the preset design phase change cycle life. Based on the equivalent elastic modulus attenuation coefficient and the cumulative damage degree, a threshold correction factor is obtained; Based on the threshold correction factor and the corresponding initial values ​​of the safety threshold, warning threshold, and limit threshold, the real-time corrected safety threshold, warning threshold, and limit threshold are obtained.

[0012] Furthermore, based on the recorded historical temperature control commands, the cumulative number of thermal cycles of the shape memory alloy wire is obtained, including: When the historical temperature control command indicates that the temperature of the shape memory alloy is heated from below the austenite transformation initiation temperature As to above the austenite transformation initiation temperature As, and then cooled to below the austenite transformation initiation temperature As, a complete thermal cycle unit is obtained. The cumulative number of thermal cycles is obtained based on the cumulative number of the thermal cycle units.

[0013] Furthermore, the threshold correction factor is obtained by the following formula: c ( t ) = 1 - m 1· α ( t ) - m 2· l ( t ) in, c ( t )for t Threshold correction factor at time, α ( t )for t The equivalent elastic modulus attenuation coefficient at time t. l ( t )for t Cumulative damage over time, m 1 represents the stiffness attenuation weighting coefficient. m 2 is the cyclic damage weighting coefficient, and m 1+ m 2≤0.8.

[0014] Furthermore, the real-time corrected safety threshold, warning threshold, and limit threshold are obtained using the following formula: e safe ( t )= max { e safe0 ( t ), e safe_min} e warning ( t )= max { e warning0 c ( t ), e warning_min} e limit ( t )= max { e limit0 c ( t ), e limit_min} in, e safe ( t ), e warning ( t )and e limit ( t ) are respectively t Safety thresholds, warning thresholds, and limit thresholds at any given time; e safe0 , e warning0 and e limit0 These are the initial values ​​for the safety threshold, warning threshold, and limit threshold, respectively. e safe_min , e warning_min and e limit_min These are the lower limit of the safety threshold, the lower limit of the warning threshold, and the lower limit of the extreme threshold, respectively.

[0015] Furthermore, based on the comparison results, a temperature control command is sent to the temperature control module, including: When the effective fatigue strain component does not exceed the safety threshold, the temperature control command instructs the temperature control module to maintain the current state, so that the shape memory alloy wire maintains the current austenitic phase working temperature; When the effective fatigue strain component is greater than the safety threshold but does not exceed the warning threshold, the temperature control command instructs the temperature control module to output a first power less than full power; When the effective fatigue strain component is greater than the warning threshold but not more than the limit threshold, the temperature control command instructs the temperature control module to output a second power that is greater than the first power but less than the full power. When the effective fatigue strain component exceeds the limit threshold, the temperature control quality indicator tells the temperature control module to output at full power and simultaneously triggers an audible and visual alarm.

[0016] Furthermore, the method also includes: performing failure analysis on the shape memory alloy wire, and when failure is determined, sending a replacement prompt instruction to replace the shape memory alloy wire; The shape memory alloy wire is determined to be faulty when at least one of the following conditions is met: The equivalent elastic modulus attenuation coefficient exceeds a preset aging threshold. The cumulative damage level reaches a preset lifespan threshold; When a temperature control command is sent to the temperature control module based on the comparison results, the change in the peak value of the effective fatigue strain component within the preset monitoring period is less than the preset safety threshold. The morphology of the surface of shape memory alloy components indicates irreversible plastic deformation.

[0017] Furthermore, the replacement of the shape memory alloy wire includes: Based on the loosening operation of the adjustable screw, the constraint of the pin ring of the adjustable screw on the failed shape memory alloy wire is released, and the failed shape memory alloy wire is disassembled. Replace with a standard-compliant shape memory alloy wire and tighten the adjustable screw to the preset torque. The stress sensing module is used to obtain the strain data of the replaced shape memory alloy wire and obtain the effective fatigue strain component after replacement. Based on the comparison results between the replaced effective fatigue strain component and the safety threshold, warning threshold, and limit threshold, a corresponding temperature control command is sent to the temperature control module; when the corresponding temperature control command is issued, if the change range of the peak value of the effective fatigue strain component within the preset monitoring period is greater than or equal to the preset safety threshold, it indicates that the replacement was successful.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following advantages: (1) By coordinating the design of the grooved connecting plate body and the SMA mesh structure, passive crack resistance is transformed into controllable failure. The groove structure can actively optimize the stress distribution path, so that fatigue cracks preferentially initiate in the pre-set controllable area at the bottom of the groove; the SMA wires are interwoven into a mesh by adjustable screws and rings, and generate real-time expansion and contraction deformation under the drive of the control module, which adaptively offsets the dynamic strain caused by wind-induced vibration and effectively suppresses the disorderly expansion of cracks. At the same time, the adjustable screws and rings allow the mesh structure formed by the SMA wires to be quickly replaced without disassembling the connecting plate body, which significantly reduces the risk of high-altitude operations and power outage losses. The closed-loop control system composed of the stress sensing module and the temperature control module realizes real-time monitoring and precise control of the stress state of the connecting plate, providing a smart solution for transmission towers that combines structural safety and operation and maintenance economy.

[0019] (2) Real-time adaptive correction of various thresholds related to the effective strain components of fatigue is achieved through resistance-stiffness mapping and thermal cycle accumulation tracking. The system reuses the existing voltage / current sampling loop of the temperature control module, obtains the equivalent elastic modulus attenuation coefficient based on the relative change rate of the real-time equivalent resistance of the shape memory alloy, and obtains the cumulative number of thermal cycles by recording historical temperature control commands and converting it into cumulative damage degree. Then, the safety, early warning and limit thresholds are dynamically adjusted by the dual-factor threshold correction factor. This scheme ensures that the thresholds are always dynamically matched with the material's actual load-bearing capacity and remaining life without increasing any hardware costs. It effectively avoids the failure risk of "not alarming when it should" after the material ages due to traditional fixed thresholds, transforms sudden failures into predictable planned maintenance, and significantly improves the safety and reliability of the active control system throughout its entire life cycle. Attached Figure Description

[0020] Figure 1 This is an overall schematic diagram of the strain-adaptive transmission tower connecting plate system of the present invention; Figure 2 This is a partially enlarged schematic diagram of the strain-adaptive transmission tower connecting plate system of the present invention; Figure 3 This is a schematic diagram illustrating the working principle of the strain-adaptive transmission tower connecting plate system of the present invention; Figure 4 This is a schematic diagram of the adjustable screw in the strain-adaptive transmission tower connecting plate system of the present invention; Figure 5 This is a flowchart of the control method for the strain-adaptive transmission tower connecting plate system of the present invention; Figure 6 This is a flowchart of the SMA filament failure analysis and replacement method of the present invention; In the diagram: 1 is a shape memory alloy wire; 2 is a distributed strain sensor; 3 is an adjustable screw; 4 is the shank of the adjustable screw; 5 is a control component; 6 is a calculation component; and 7 is an external power supply. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are in a very simplified form and are not precisely proportional, and are only used to facilitate and clearly illustrate the present invention. The examples described in this application are merely some embodiments of the present invention, and not all embodiments. Based on the spirit of the present invention, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of the present invention.

[0022] Example 1, See Figure 1-4 This invention discloses a strain-adaptive transmission tower connecting plate system, comprising: a connecting plate structure, a mesh structure, a stress sensing module, a temperature control module, and a control module.

[0023] The connecting plate structure, serving as the main load-bearing component, employs a grooved design to confine the crack-prone area within a preset, controllable range. The mesh structure, formed by shape memory alloy (SMA) wires interlaced with adjustable screw rings above the grooves, actively generates expansion and contraction deformation to offset or alleviate the dynamic strain on the connecting plate. The stress sensing module, temperature control module, and control module work together to monitor the strain state of the connecting plate in real time and perform closed-loop regulation of the SMA wire's operating temperature based on a preset control strategy, achieving adaptive adjustment of the stress state of the connecting plate.

[0024] like Figure 1 and 2 As shown, the connecting plate structure includes a plate-shaped base and grooves provided on the plate-shaped base. The plate-shaped base is made of high-strength steel and is rectangular in shape. Its geometric dimensions are designed to match the load rating and spatial position of the connected tower components.

[0025] The groove is located in the central region of the plate-like substrate, with its walls perpendicular to the main plane of the plate. The groove is not simply for weight reduction or process requirements, but rather the core structural basis of the "controllable damage" concept of this invention: by weakening the cross-section at the groove, the stress distribution path of the connecting plate is actively optimized, causing stress concentration and fatigue cracks generated under dynamic alternating loads such as wind-induced vibration and conductor galloping to preferentially initiate and propagate at the bottom of the groove. This strictly confines potential damage to this controllable area, preventing the disorderly spread of cracks to the critical load-bearing area connecting the connecting plate and the tower body.

[0026] Multiple screw holes are evenly spaced longitudinally on the two opposing groove walls of the groove, and an adjustable screw 3 is installed in each screw hole. The adjustable screw 3 has a threaded cylindrical structure with an adjustment head at its end for easy tool operation. The adjustable screw ring 4 is designed as a ring-shaped connector adapted to the screw, with a pre-drilled hole on the inner side to match the end of the SMA wire. The two form a detachable connection through threaded engagement: when the SMA wire needs to be replaced, the adjustable screw 3 is loosened with a tool to release the pressure between it and the ring 4, thus releasing the clamping fixation on the end of the SMA wire; after the new SMA wire is inserted into the ring along the preset path and adjusted into place, the screw is tightened in the opposite direction, and the threaded locking force makes the ring tightly engage with the alloy wire, achieving a firm fixation. This design allows the replacement of the SMA component without any modification to the main structure of the connecting plate, ensuring the convenience of the replacement process and the integrity of the connecting plate structure.

[0027] Furthermore, the connection between the adjustable screw 3 and the nail ring 4 is not a simple rigid fixation, but allows the SMA filament to produce small, controllable slippage and rotation during the phase change process, forming a mechanical rotational pair effect, thus avoiding secondary stress concentration at the end when the SMA contracts or relaxes.

[0028] Furthermore, an insulation layer is precisely laid above the groove and below or above the SMA mesh structure. This insulation layer is made of aerogel composite material or ceramic fiber, with a thermal conductivity of less than 0.03 W / (m·K). It is used to thermally isolate the external ambient temperature (such as low temperature in winter, high temperature in summer, solar radiation, etc.) from the working area of ​​the SMA filament, ensuring that the working temperature fluctuation range of the SMA is controlled within ±2℃, and avoiding misjudgment or inaccurate temperature control caused by external temperature interference.

[0029] like Figure 2 As shown, the mesh structure is formed by multiple shape memory alloy wires 1 connected in an interlaced manner above the groove via the nail rings 4 at the top of the multiple adjustable screws 3. The SMA wires 1 are distributed in a mesh pattern above the groove, with the mesh segments interlacing to form a spatial mechanical coupling system.

[0030] The SMA wire 1 is made of a nickel-titanium based shape memory alloy with thermoelastic martensitic phase transformation properties. This alloy exhibits martensitic and austenitic phases at different temperatures, with a reversible phase transformation between the two phases. Specific phase transformation temperature parameters are as follows: Martensitic phase transformation initiation temperature Ms = 10℃; The complete martensitic transformation temperature Mf = 40℃; The austenitic phase transformation initiation temperature As = 40℃; The complete austenite transformation temperature Af = 70℃.

[0031] At low temperatures, the martensitic phase is soft and easily deformable, and can be easily bent or stretched; at high temperatures, the austenitic phase is hard and has high strength. When SMA wire is heated to above Af (70℃), the alloy crystal structure completely transforms from martensite to austenite and strongly recovers to its original "memory" shape, producing significant recovery stress and shrinkage deformation.

[0032] The target operating temperature range of this structure is: The operating temperature range is 10℃ to 80℃. Within this range, the control system maintains the SMA wire in the austenitic phase through the Joule heating effect (the typical operating temperature platform is set at 75℃ to 80℃), ensuring it maintains high stiffness and high load-bearing capacity. Regardless of whether the connecting plate is subjected to tensile or compressive stress, the SMA wire should remain in the austenitic phase, without involving the martensitic phase, to ensure the stable operation of its hyperelasticity and stress-induced regulation functions.

[0033] The layout parameters of the SMA mesh structure (including the cross-sectional area, pretension, and spatial coordinates of each mesh segment) are not empirically determined, but rather offline optimized using a multi-objective topology optimization algorithm (such as the NSGA-II genetic algorithm). The optimization objectives are: maximizing the strain uniformity at the bottom of the groove, minimizing the total mass of the SMA, and minimizing the phase transformation response time. The constraints are: the overall stiffness of the connecting plate is not less than 90% of the original design stiffness, and the stress of each SMA segment is always lower than its yield strength. The optimized non-uniform mesh layout forms a unique mechanical coupling with the groove-type connecting plate, enabling it to flexibly adapt to complex strains in multiple directions under wind-induced vibration, effectively improving the structural deformation coordination and load-bearing stability.

[0034] like Figure 2 and Figure 3 As shown, the stress sensing module includes multiple distributed strain sensors 2 deployed at the bottom of the groove. These distributed strain sensors 2 are precisely positioned in the critical stress areas at the bottom of the groove, employing high-sensitivity resistance strain gauges or fiber optic strain sensors. They acquire dynamic strain data at the groove in real time via reliable data transmission methods (such as shielded cables or wireless transmission modules), and efficiently transmit the complete data to the control module, providing accurate data for structural condition monitoring and closed-loop control.

[0035] like Figure 3 As shown, the temperature control module includes an external power supply 7. This external power supply 7 is a power device with wide voltage regulation, and its voltage output range can be flexibly set according to actual operating conditions. The output terminals of the external power supply 7 are precisely connected to both ends of the shape memory alloy wire 1, forming a closed heating circuit.

[0036] The temperature control module, based on the temperature control commands issued by the control module, precisely adjusts the output voltage to change the intensity of the current flowing through the SMA wire. The Joule heat generated when the current flows through the SMA wire increases or decreases regularly with the voltage change, thereby achieving precise and real-time control of the SMA wire temperature, ensuring that the alloy can quickly respond to the strain adjustment requirements of the connecting plate and maintain the preset operating temperature.

[0037] like Figure 3 As shown, the control module includes a calculation component 6 and a control component 5. The calculation component 6 is communicatively connected to the stress sensing module and receives its real-time acquired dynamic strain data; the control component 5 is communicatively connected to both the calculation component 6 and the temperature control module.

[0038] The calculation component 6 is mainly used to perform preprocessing such as filtering and noise reduction on the received strain data, and compare it with relevant thresholds to generate clear comparison results; the control component 5 sends corresponding temperature control commands to the temperature control module based on preset control logic and actual working conditions to ensure the controllability and operational safety of the connecting plate structure.

[0039] Example 2 This embodiment provides the control method for the transmission tower connecting plate structure of Embodiment 1.

[0040] like Figure 5 The control method mainly includes the following steps: S1: Based on the dynamic strain data, the effective strain components of fatigue are obtained.

[0041] The stress sensing module acquires dynamic strain data of the bottom of the groove in real time at a preset sampling frequency (e.g., 10 Hz). After receiving the dynamic strain data, the calculation component 6 performs preprocessing using a wavelet packet-empirical mode decomposition (WP-EMD) joint algorithm to extract the effective fatigue strain components. The specific steps are as follows: S11. Based on the dynamic strain data, perform three-level wavelet packet decomposition to obtain 8 sub-frequency band signals.

[0042] S12. Based on the characteristic frequency range of structural vibration, select target sub-bands containing mechanical responses from the obtained 8 sub-band signals.

[0043] Among them, the target sub-frequency band usually corresponds to the wind-induced vibration main frequency of 0.1~2 Hz and the conductor galloping frequency.

[0044] S13. Based on empirical mode decomposition, the target sub-band signal is adaptively decomposed to obtain multiple intrinsic mode function (IMF) components.

[0045] S14. Based on the sample entropy calculation, each IMF component is screened to obtain the retained IMF components.

[0046] The screening method is as follows: retain IMF components whose sample entropy is within a preset threshold range (such as 0.3~0.8), which corresponds to the true deformation information of the structure; and remove components whose sample entropy is too high (high frequency noise) or too low (extremely low frequency drift).

[0047] S15. Reconstruct the signal based on the retained IMF components to obtain the current time. t Fatigue effective strain component e f ( t ) .

[0048] By using the above-mentioned WP-EMD combined denoising, the signal-to-noise ratio can be improved by more than 15 dB, avoiding the controller's false response to instantaneous gust peaks or electromagnetic interference, and ensuring that subsequent comparisons and temperature control decisions are based on real and effective structural fatigue information.

[0049] S2. Determine the safety threshold, warning threshold, and limit threshold.

[0050] In this embodiment, the safety threshold, warning threshold, and ultimate threshold are determined using a real-time threshold correction mechanism based on the aging state of SMA materials. This mechanism fully reuses the existing voltage / current sampling function of the temperature control module, requiring no additional sensors. Specifically, it includes the following sub-steps: S21: Determine the corresponding initial values ​​for the safety threshold, warning threshold, and limit threshold.

[0051] In this embodiment, the initial value of the security threshold e safe0 =800 with The initial value of the warning threshold e warning0 =1200 with The initial value of the limit threshold e limit0 =1600 with In other embodiments, the initial values ​​of the safety threshold, warning threshold, and limit threshold can be set to other values ​​based on expert experience or other means.

[0052] S22. Obtain the real-time current and real-time voltage of the shape memory alloy wire to obtain the real-time relative resistance change rate of the shape memory alloy wire.

[0053] The temperature control module, while outputting Joule heat power to the SMA filament, can also sample the real-time voltage across the SMA filament. U ( t ) and real-time currentI ( t Based on real-time voltage U ( t ) and real-time current I ( t The real-time equivalent resistance of the SMA wire is obtained as follows: R ( t )= I ( t ) U ( t Based on real-time equivalent resistance... R ( t The initial equivalent resistance of the SMA wire as specified at the factory. R 0, yielding the relative rate of change of resistance: Δ R ( t )= ( R ( t ) R 0) / R 0 In the formula, R 0 represents the initial resistance value of the SMA wire in its brand-new condition, measured at a reference temperature (e.g., 20°C) and under zero stress. This value is pre-stored in the system through factory electrical parameter calibration.

[0054] Due to the increased dislocation density and finer martensite laths within the SMA after long-term thermal cycling, its electrical resistance monotonically increases, therefore Δ R ( t It can directly characterize the degree of degradation of the internal microstructure of a material.

[0055] S23. Based on the relative rate of change of resistance and the preset resistance-stiffness mapping coefficient, the equivalent elastic modulus attenuation coefficient of the shape memory alloy wire is obtained.

[0056] Specifically, if the resistance-stiffness mapping coefficient preset in the offline calibration test is denoted as... k E Then, the equivalent elastic modulus attenuation coefficient of SMA wire can be obtained as: α ( t )= k E Δ R ( t ) In the formula, k E This is a dimensionless calibration coefficient, characterizing the relative decrease in elastic modulus corresponding to a unit increase in resistance, pre-determined by batches of SMA wire in standard fatigue tests. For example, when measured... α (t When )=0.10, it indicates that the equivalent elastic modulus of SMA has decreased by 10%, and its stress-strain response slope decreases accordingly, weakening its active control capability.

[0057] S24. Record temperature control commands. Based on the recorded historical temperature control commands, obtain the cumulative number of thermal cycles of the shape memory alloy wire. Based on the cumulative number of thermal cycles and the preset design phase change cycle life, obtain the cumulative damage degree.

[0058] Specifically, the calculation component 6 can count the historical temperature control commands of the control component 5. When it detects that a historical temperature control command indicates the temperature of the SMA filament has fallen below the austenitic phase transformation initiation temperature... As Heated to above (40℃) As and then cooled to below As When the time is equal to 1, it is recorded as a complete thermal cycle unit.

[0059] Based on the cumulative number of thermal cycle units, we can obtain t Cumulative number of thermal cycles at any given time N ( t Furthermore, based on the cumulative number of thermal cycles... N ( t The maximum permissible phase change cycle life of the SMA filament under the preset design conditions. N max The cumulative damage can be obtained. l ( t ): l ( t )= N ( t ) / N max In the formula, l ( t ) is a normalized Miner type damage index, when l ( t When the value reaches 1, it indicates that the SMA has entered the critical state of fatigue failure.

[0060] S25. Based on the equivalent elastic modulus attenuation coefficient and cumulative damage degree, the threshold correction factor is obtained.

[0061] Specifically, the equivalent elastic modulus attenuation coefficient is denoted as... α ( t The cumulative damage is recorded as... l ( t Then the threshold correction factor can be obtained. c ( t ): c ( t)=1 m 1 α ( t ) m 2 l ( t ) In the formula, m 1 represents the stiffness attenuation weighting coefficient, with a value ranging from 0.15. 0.30; m 2 represents the cyclic damage weighting coefficient, with a value ranging from 0.20. 0.40; and satisfies m 1+ m 2≤0.8, to ensure that the correction factor is always positive and to avoid excessively lowering the threshold.

[0062] Correction factor c ( t The degradation rate decreases monotonically as SMA yarn ages. When SMA yarn is brand new, α ( t )=0、 l ( t ) = 0, therefore c ( t )=1, the threshold remains at its initial value; as service time increases, c ( t Linear reduction enables adaptive threshold reduction, preventing the safety hazard of not triggering an alarm when it occurs.

[0063] S26. Based on the initial values ​​of the threshold correction factor and the corresponding safety threshold, warning threshold and limit threshold, obtain the real-time corrected safety threshold, warning threshold and limit threshold.

[0064] Specifically, the real-time corrected safety threshold, warning threshold, and limit threshold are obtained using the following formula: e safe ( t )= max { e safe0 ( t ), e safe_min} e warning ( t )= max { e warning0 c ( t ), e warning_min} e limit ( t )= max { e limit0 c ( t ), e limit_min} in, e safe ( t ), e warning ( t )and e limit ( t ) are respectively t Safety thresholds, warning thresholds, and limit thresholds at any given time; e safe0 , e warning0 and e limit0 These are the initial values ​​for the safety threshold, warning threshold, and limit threshold, respectively. e safe_min , e warning_min and e limit_min These are the lower limits of the safety threshold, the warning threshold, and the extreme threshold, respectively. As an example, in this embodiment, we take... e safe0 =800 with , e warning0 = 1200 with , e limit0 = 1600 με, and take e safe_min =600 with , e warning_min =900 me, eh limit_min =1200 with .

[0065] By setting lower limits for safety thresholds, warning thresholds, and extreme thresholds, we can prevent excessive downward pressure on thresholds under extreme operating conditions, which could lead to frequent false alarms in the system and ensure basic operational safety margins.

[0066] It should be noted that in other embodiments, fixed safety thresholds, warning thresholds, and limit thresholds can also be used. However, compared to fixed thresholds, by making real-time corrections to the safety thresholds, warning thresholds, and limit thresholds, the actual state of the shape memory alloy material can be more closely approximated, thereby allowing for better control of the temperature and stress of the shape memory alloy wire.

[0067] S3. Compare the effective fatigue strain component with the safety threshold, warning threshold and limit threshold.

[0068] Specifically, the comparison can be performed in the computational component, including determining the magnitude of the effective fatigue strain component relative to the safety threshold, warning threshold, and ultimate threshold.

[0069] S4. Based on the comparison results, send a temperature control command to the temperature control module.

[0070] Specifically, control component 5 in the control module executes a hierarchical response strategy based on the comparison results, with the specific correspondence as follows: When the comparison results indicate the effective strain component of fatigue e f ( t (Does not exceed the real-time security threshold) e safe ( t The control component 5 sends a temperature control command to the temperature control module to activate the maintenance mode. Specifically, the temperature control module maintains the SMA wire at the current austenitic phase operating temperature (e.g., 75°C). (80℃), while performing periodic sampling and threshold comparison without additional heating.

[0071] When the comparison results indicate the effective strain component of fatigue e f ( t (greater than the real-time security threshold) e safe ( t And not exceeding the real-time warning threshold. e warning ( t The control component 5 sends a temperature control command to the temperature control module to activate the low-power heating mode. Specifically, the temperature control module activates the low-power heating mode at a first power level (e.g., 30% of the rated power). The heating output is 50%, causing the SMA wire temperature to slowly rise above Af (e.g., 70°C). Utilizing the restoring stress and shrinkage deformation generated by the austenitic phase transformation, a reverse constraint force is formed in the groove area of ​​the connecting plate, actively counteracting the peak tensile strain caused by wind-induced vibration, thus entering an adaptive control state. The control module internally marks the state as "yellow warning," records the event timescale and strain amplitude, but does not trigger external audible and visual alarms.

[0072] When fatigue effective strain component εf ( t () Greater than the real-time warning threshold e warning ( t And not exceeding the real-time limit threshold. e limit ( t The control component 5 sends a temperature control command to the temperature control module to activate the medium-power heating mode. Specifically, the temperature control module operates at a second power (e.g., 60% of the rated power). Heating output is performed at 80%. This second power, between the first and full power, is used to shorten the phase change response time of the SMA filament and prevent temperature control overshoot from causing the SMA to enter the irreversible aging zone. The control module internally marks an "orange warning" state, records the event time stamp and strain amplitude, but does not trigger external audible and visual alarms.

[0073] When fatigue effective strain component e f ( t () greater than the real-time limit threshold e limit ( t The control component 5 sends a temperature control command to the temperature control module to instruct it to execute a preset destructive action. Specifically, the temperature control module immediately outputs full power (100% rated power), causing the SMA wire to complete the austenitic phase transformation in a very short time (usually <5s), generating maximum recovery force, strongly contracting and pulling the local deformation of the connecting plate back to the controllable range. At the same time, an audible and visual alarm is triggered, and a "controllable destructive start" signal is sent to the power transmission operation and maintenance monitoring platform.

[0074] The technical essence of the "preset destructive action" here is the active safety release at the structural level: when the external wind load exceeds the adaptive adjustment capability of the SMA, the system no longer pursues complete suppression of strain, but instead uses the maximum restoring force of the SMA coupled with the geometric stress concentration effect of the grooved connecting plate to forcibly lock the plastic deformation and crack initiation in the preset sacrificial zone at the bottom of the groove, so as to ensure that the crack does not spread outward as much as possible.

[0075] S5. Perform failure analysis on the shape memory alloy wire. When failure is determined, send a replacement prompt command to replace the shape memory alloy wire.

[0076] The SMA wire is determined to be faulty when at least one of the following conditions is met, and the control module sends a replacement prompt command to replace the SMA wire: Scenario 1: The equivalent elastic modulus attenuation coefficient exceeds the preset aging threshold. For example, if the equivalent elastic modulus attenuation coefficient α ( t Exceeding the preset aging threshold αth =0.10 indicates that the internal microstructure of SMA has been severely degraded and the active control capability has been irreversibly reduced, confirming the failure of SMA filament.

[0077] Scenario 2: The cumulative damage reaches the preset lifespan threshold. For example, cumulative damage l ( t Reaching the preset lifespan threshold l th =0.85 indicates that the thermal cycle life is about to be exhausted, the active control capability is irreversibly reduced, and the SMA filament has failed.

[0078] Scenario 3: Phase transition response failure determination If, within a preset monitoring period (e.g., three consecutive sampling periods, or 0.3s) after sending a temperature control command to the temperature control module based on the comparison results, the peak value change of the effective fatigue strain component is less than a preset safety threshold (e.g., a decrease of <5%), a phase transformation response failure determination result is obtained. This indicates that the SMA failed to undergo the expected austenitic phase transformation or that the recovery stress generated by the phase transformation was insufficient to offset the external load, and the component failed due to functional loss.

[0079] Scenario 4: Morphological inspection of the surface of shape memory alloy components indicates irreversible plastic deformation. Based on the morphological inspection of the SMA filament surface (such as UAV visual inspection or visual inspection by maintenance personnel), the plastic deformation judgment result is obtained. When obvious irreversible plastic deformation (such as bending, torsion, surface cracking or filament breakage) is detected, the component is directly judged to have failed.

[0080] like Figure 6 As shown, the replacement of the SMA wire includes the following steps: S51, Disassembling the failed component Based on the loosening operation of the adjustable screw 3, the constraint of the pin ring 4 of the adjustable screw 3 on the failed SMA wire is released, and the failed SMA wire is disassembled.

[0081] S52, Install new components Replace with one that meets the standard (consistent with factory-calibrated parameters, including phase transition temperature and initial resistance). R 0. Select SMA wires (with cross-sectional dimensions and pretension) and tighten the adjustable screws 3 on both sides to a preset torque. The preset torque is determined based on the SMA pretension parameters output by the multi-objective topology optimization algorithm to ensure that the contact resistance and heat conduction efficiency between the replaced SMA wire and the connecting plate groove wall are within the design range.

[0082] S53, Replacement Effect Verification The stress sensing module acquires strain data of the replaced SMA wire to obtain the effective fatigue strain component after replacement. Based on the comparison between the effective fatigue strain component after replacement and the final output threshold, a corresponding temperature control command is sent to the temperature control module. If, after the corresponding temperature control command is issued, the peak value of the effective fatigue strain component changes by a factor greater than or equal to a preset safety threshold (e.g., a decrease of ≥15%) within a preset monitoring period, and the equivalent fatigue stress amplitude is lower than the real-time warning threshold, then the replacement is considered successful; otherwise, the disassembly and installation operations are repeated until the requirements are met.

[0083] In summary, compared with the prior art, the present invention has the following advantages: 1. Through the synergistic design of the grooved connecting plate body and the SMA mesh structure, passive crack resistance is transformed into controllable failure. The groove structure actively optimizes the stress distribution path, causing fatigue cracks to preferentially initiate in the pre-defined controllable area at the bottom of the groove. The SMA wires, interwoven with adjustable screws and rings, generate real-time expansion and contraction deformation under the drive of the control module, adaptively offsetting the dynamic strain caused by wind-induced vibration and effectively suppressing the disorderly propagation of cracks. Simultaneously, the adjustable screws and rings allow the mesh structure formed by the SMA wires to be quickly replaced without disassembling the connecting plate body, significantly reducing the risks of high-altitude operations and power outage losses. The closed-loop control system, composed of a stress sensing module and a temperature control module, enables real-time monitoring and precise control of the stress state of the connecting plate, providing a smart solution for transmission towers that combines structural safety and economical operation and maintenance.

[0084] 2. By employing resistance-stiffness mapping and thermal cycle accumulation tracking, real-time adaptive correction of thresholds related to effective strain components during fatigue is achieved. The system reuses the existing voltage / current sampling loop of the temperature control module, obtaining the equivalent elastic modulus attenuation coefficient based on the relative change rate of the real-time equivalent resistance of the shape memory alloy. Simultaneously, it obtains the cumulative number of thermal cycles by recording historical temperature control commands and converts it into cumulative damage. Then, a dual-factor threshold correction factor dynamically lowers the safety, warning, and ultimate thresholds. This scheme, without increasing any hardware costs, ensures that the thresholds are always dynamically matched with the material's actual load-bearing capacity and remaining lifespan. This effectively avoids the failure risk of traditional fixed thresholds failing to alarm when necessary after material aging, transforming sudden failures into predictable planned maintenance, and significantly improving the safety and reliability of the active control system throughout its entire lifecycle.

[0085] This disclosure can be a system, method, and / or computer program product. A computer program product may include a computer-readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of this disclosure.

[0086] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0087] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0088] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A strain-adapted transmission tower tie plate system, comprising: include: A connecting plate structure includes a plate-shaped base and a groove provided on the plate-shaped base, wherein multiple adjustable screws are installed on two opposite groove walls of the groove; The mesh structure is formed by shape memory alloy wires being interlaced and connected above the grooves through the nail rings at the top of the plurality of adjustable screws; A stress sensing module is used to collect dynamic strain data of the groove in real time; A temperature control module is used to adjust the current and voltage of the shape memory alloy wire to control its temperature. The control module, connected to the stress sensing module and the temperature control module respectively, is used to adjust the working temperature of the shape memory alloy based on the received dynamic strain data to generate corresponding expansion and contraction deformation, so as to counteract the dynamic strain on the connecting plate structure.

2. The strain-adapted transmission tower tie plate system of claim 1, wherein, The shape memory alloy exhibits the characteristic of reversible phase transformation between martensite and austenite phases.

3. The strain-adapted transmission tower tie plate system of claim 1, wherein, A heat insulation layer is also laid above the groove of the connecting plate structure to reduce the interference of the external ambient temperature on the working temperature of the shape memory alloy.

4. The strain-adapted transmission tower tie plate system of claim 1, wherein, The stress sensing module includes multiple distributed strain sensors deployed at the bottom of the groove.

5. A control method of the strain-adapted transmission tower tie plate system according to any one of claims 1 to 4, characterized by, Includes the following steps: Based on the dynamic strain data, the effective fatigue strain components are obtained; Determine the safety threshold, warning threshold, and limit threshold; The effective fatigue strain component is compared with the safety threshold, warning threshold, and limit threshold. Based on the comparison results, a temperature control command is sent to the temperature control module.

6. The control method according to claim 5, characterized by Determine the safety threshold, warning threshold, and limit threshold, including: Determine the corresponding initial values ​​for the safety threshold, warning threshold, and limit threshold; The real-time current and real-time voltage of the shape memory alloy wire are obtained to obtain the real-time relative rate of change of resistance of the shape memory alloy wire; Based on the relative rate of change of resistance and the preset resistance-stiffness mapping coefficient, the equivalent elastic modulus attenuation coefficient of the shape memory alloy wire is obtained. Record temperature control commands, obtain the cumulative number of thermal cycles of the shape memory alloy wire based on the recorded historical temperature control commands, and obtain the cumulative damage degree based on the cumulative number of thermal cycles and the preset design phase change cycle life. Based on the equivalent elastic modulus attenuation coefficient and the cumulative damage degree, a threshold correction factor is obtained; Based on the threshold correction factor and the corresponding initial values ​​of the safety threshold, warning threshold, and limit threshold, the real-time corrected safety threshold, warning threshold, and limit threshold are obtained.

7. The control method according to claim 6, characterized in that, Based on recorded historical temperature control commands, the cumulative number of thermal cycles of the shape memory alloy wire is obtained, including: When the historical temperature control command indicates that the temperature of the shape memory alloy is heated from below the austenite transformation initiation temperature As to above the austenite transformation initiation temperature As, and then cooled to below the austenite transformation initiation temperature As, a complete thermal cycle unit is obtained. The cumulative number of thermal cycles is obtained based on the cumulative number of the thermal cycle units.

8. The control method according to claim 6, characterized by, The threshold correction factor is obtained by the following formula: γ ( t ) = 1 - μ 1· α ( t ) - μ 2· λ ( t ) in, γ ( t )for t Threshold correction factor at time, α ( t )for t The equivalent elastic modulus attenuation coefficient at time t. λ ( t )for t Cumulative damage over time, μ 1 represents the stiffness attenuation weighting coefficient. μ 2 is the cyclic damage weighting coefficient, and μ 1+ μ 2≤0.

8.

9. The control method according to claim 8, characterized by, The real-time corrected safety threshold, warning threshold, and limit threshold are obtained by the following formula: ε safe ( t )= max { ε safe0 ( t ), ε safe_min} ε warning ( t )= max { ε warning0 γ ( t ), ε warning_min} ε limit ( t )= max { ε limit0 γ ( t ), ε limit_min} in, ε safe ( t ), ε warning ( t )and ε limit ( t ) are respectively t Safety thresholds, warning thresholds, and limit thresholds at any given time; ε safe0 , ε warning0 and ε limit0 These are the initial values ​​for the safety threshold, warning threshold, and limit threshold, respectively. ε safe_min , ε warning_min and ε limit_min These are the lower limit of the safety threshold, the lower limit of the warning threshold, and the lower limit of the extreme threshold, respectively.

10. The control method according to claim 5 or 6, characterized in that, Based on the comparison results, a temperature control command is sent to the temperature control module, including: When the effective fatigue strain component does not exceed the safety threshold, the temperature control command instructs the temperature control module to maintain the shape memory alloy wire at the current austenitic phase working temperature. When the effective fatigue strain component is greater than the safety threshold but does not exceed the warning threshold, the temperature control command instructs the temperature control module to output heating power at a first power less than full power; When the effective fatigue strain component is greater than the warning threshold but not more than the limit threshold, the temperature control command instructs the temperature control module to output heating power at a second power that is greater than the first power but less than the full power. When the effective fatigue strain component exceeds the limit threshold, the temperature control quality indicator tells the temperature control module to output heating at full power and simultaneously triggers an audible and visual alarm.

11. The control method according to claim 6, characterized by, The method further includes: Failure analysis is performed on the shape memory alloy wire, and when failure is determined, a replacement prompt command for replacing the shape memory alloy wire is sent. The shape memory alloy wire is determined to be faulty when at least one of the following conditions is met: The equivalent elastic modulus attenuation coefficient exceeds a preset aging threshold. The cumulative damage level reaches a preset lifespan threshold; When a temperature control command is sent to the temperature control module based on the comparison results, the change in the peak value of the effective fatigue strain component within the preset monitoring period is less than the preset safety threshold. The morphology of the surface of shape memory alloy components indicates irreversible plastic deformation.

12. The method of use of claim 11, wherein, The replacement of the shape memory alloy wire includes: Based on the loosening operation of the adjustable screw, the constraint of the pin ring of the adjustable screw on the failed shape memory alloy wire is released, and the failed shape memory alloy wire is disassembled. Replace with a standard-compliant shape memory alloy wire and tighten the adjustable screw to the preset torque. The stress sensing module is used to obtain the strain data of the replaced shape memory alloy wire and obtain the effective fatigue strain component after replacement. Based on the comparison results between the replaced effective fatigue strain component and the safety threshold, warning threshold and limit threshold, a corresponding temperature control command is sent to the temperature control module; when the corresponding temperature control command is issued, if the change range of the peak value of the effective fatigue strain component within the preset monitoring period is greater than or equal to the preset safety threshold, it indicates that the replacement was successful.

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