Temporary shape memory alloy suspension bridge sling reinforcing device based on strain detection

Abstract

The shape memory alloy suspension bridge sling temporary reinforcing device based on strain detection comprises a columnar connecting frame and a control unit, the columnar connecting frame is installed between a sling and a lower end crack, and the columnar connecting frame comprises an upper anchor cup installed on the sling and a lower anchor cup installed on the lower end crack; the lower anchor cup is mounted at the lower part of the lower end crack; the shape memory alloy reinforcing rib is arranged on the outer side of the sling, and two ends of the shape memory alloy reinforcing rib in the length direction extend to the outer sides of the upper anchor cup and the lower anchor cup in parallel and are fixed through anchoring rings; the control unit is connected with the shape memory alloy reinforcing rib and used for detecting the strain of the shape memory alloy reinforcing rib and controlling the shape memory alloy reinforcing rib. The strain condition of the sling is monitored in real time, the shape memory alloy reinforcing rib is rapidly heated when the strain reaches a critical value, rapid temporary repair after the end of the sling is cracked is achieved, and the problems that in the prior art, the wire breakage and fracture risk of the sling cannot be detected, the damaged sling cannot be rapidly reinforced, and a reinforcing device and the sling cannot be cooperatively stressed are solved.

Description

Technical Field

[0001] The invention relates to the technical field of sling reinforcement, and in particular to a temporary reinforcement device for slings of a shape memory alloy suspension bridge based on strain detection. Background Art

[0002] As vital transportation infrastructure, long-span suspension bridges are widely used across multiple regions. Suspension cables are key load-bearing components of suspension bridge structures, primarily connecting the bridge's main beams and cables and carrying the load. Their safety directly impacts the stability and service life of the bridge structure. As bridges age, the cables are subjected to long-term, complex loads, and their internal steel wires break due to fatigue damage. Especially under extreme loads, wire breakage can cause sudden breakage of the suspension cables, triggering a chain reaction of breakage in other cables, leading to structural failure and a serious threat to bridge safety.

[0003] Shape memory alloys (SMAs) are versatile alloys with shape memory, enabling deformation through temperature control. They are commonly used in engineering for reinforcement and repair. Currently, they are primarily used to enhance mechanical properties before assembly. For example, SMAs can be used to pre-tension slings before installation to reduce prestress loss.

[0004] Bridge cables are prone to breakage due to service life and design flaws, necessitating regular inspection and maintenance. Analysis of fracture data reveals that these breakages typically occur in the same location. To address this issue and reduce the cost of regular inspections, existing technology employs remote monitoring. However, as cable wire breakage is often a hidden process, remote monitoring cannot effectively guarantee safety.

[0005] Therefore, how to effectively monitor the condition of the suspension cables, promptly detect broken wires, and implement temporary and rapid repair measures to prevent broken wires from triggering a chain reaction has become a key issue in the safety management of suspension bridges. Furthermore, traditional passive reinforcement devices cannot coordinate with the suspension cables in terms of force, resulting in limited reinforcement effectiveness. Summary of the Invention

[0006] The purpose of the present invention is to provide a temporary reinforcement device for shape memory alloy suspension bridge cables based on strain detection in order to solve the above problems, so as to solve the problems that the existing technology cannot detect the risk of broken wires and breakage of cables, cannot quickly reinforce damaged cables, and the reinforcement device cannot cooperate with the cables to bear force.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a temporary reinforcement device for a shape memory alloy suspension bridge cable based on strain detection, comprising a columnar connecting frame and a control unit, wherein the columnar connecting frame is installed between the cable and the lower end crack, and the columnar connecting frame includes:

[0008] upper anchor cup, mounted on the sling;

[0009] The lower anchor cup is installed at the lower part of the lower end crack; the upper anchor cup and the lower anchor cup are made of low-carbon steel material, and are designed as a hollow structure so that the sling can pass through it. The anchor position is designed to fix it on the sling, and the shape and size are set according to the installation sling.

[0010] The upper anchor cup and the lower anchor cup are opened around the center ring for installing shape memory alloy reinforcement bars. The shape memory alloy reinforcement bars are arranged on the outside of the sling, and the two ends in the length direction extend parallel to the outside of the upper anchor cup and the lower anchor cup and are fixed by anchor rings; the diameter of the shape memory alloy reinforcement bars is greater than 10mm, and the number is set to 8-20.

[0011] The control unit is connected to the shape memory alloy reinforcement bar and is used to detect strain in the shape memory alloy reinforcement bar and control the shape memory alloy reinforcement bar. The control unit is used to provide power, detect strain, determine the current risk status of the sling, and control the shape memory alloy reinforcement bar to heat up and achieve contraction.

[0012] Preferably, ordinary metal reinforcement bars are also included, arranged alongside shape-memory alloy reinforcement bars between the upper and lower anchor cups. This arrangement, where the shape-memory alloy reinforcement bars and ordinary metal reinforcement bars are interlaced between the upper and lower anchor rings, can reduce costs while ensuring effectiveness. It should be noted that a middle anchor cup can also be provided, with shape-memory alloy reinforcement bars installed between the upper and middle anchor cups, and ordinary metal reinforcement bars installed between the middle and lower anchor cups. These overlapping installations can reduce the length of the shape-memory alloy reinforcement bars and lower material costs.

[0013] Preferably, the control unit includes a direct power supply heating module or an indirect power supply heating module. The direct power supply heating module is installed at both ends of the shape memory alloy reinforcement bar to heat the shape memory alloy reinforcement bar by applying electricity; the indirect power supply heating module is arranged around the shape memory alloy reinforcement bar. Some existing shape memory alloys have the effect of heating by applying electricity, achieving heat and contraction through direct application of electricity. However, the material cost is relatively high. Therefore, the shape memory alloy reinforcement bar can be heated by installing a heating wire around the periphery of the shape memory alloy reinforcement bar.

[0014] Preferably, a buffer pad is further included, which is sleeved on the shape memory alloy reinforcement bar and is respectively arranged between the shape memory alloy reinforcement bar and the upper anchor cup and the lower anchor cup. The buffer pad has a thickness of ≥3mm and is an elastic gasket with insulation capability that can be used to isolate the contact between the reinforcement bar and the anchor cup. The elastic gasket is arranged between the anchor ring and the anchor cup to offset the deformation caused by the broken wire of the sling. When the sling wire breaks, the strain of the sling increases. Since the reinforcement bar has been anchored to the sling through the anchor ring and the anchor cup at this time, if the reinforcement bar is subjected to the sling force too early, it may lead to yielding or failure. At the same time, due to the lack of pre-tensioning force, the reinforcement bar is unevenly stressed, resulting in reduced reinforcement capacity. Therefore, an elastic gasket is arranged between the anchor ring and the anchor cup. When the strain of the sling increases, the anchor cup increases with the deformation spacing of the sling, thereby squeezing the elastic gasket. The elastic gasket is compressed, offsetting the deformation at the end anchorage, and preventing the reinforcement bar from bearing the axial force. Assuming that the radius of the anchor ring is r2 and the radius of the elastic gasket is area r3, the anchor ring needs to be covered, which is determined according to the radius of the reinforcement bar and is set to r3 = 1.5r2.

[0015] The elastic gasket is made of epoxy resin with a high percentage of glass fiber. The elastic modulus E3 of the elastic gasket is set as follows: Referring to the iron-based shape memory alloy used for the reinforcement, assuming the elastic modulus of the shape memory alloy is E2, the elastic gasket material is optimized through multi-layer composite structure, and the overall modulus E3 is set to (0.1-0.2)E2. Assuming the yield strength of the elastic gasket material is σ2, σ2 ≤ 0.1σ1. To ensure that the gasket thickness is sufficient to offset the deformation of the sling, a calculation principle for the sling gasket thickness is proposed: referring to the steel parallel wire sling under normal load conditions, the sling strain δ1 typically ranges from 0.1% to 0.4%. When the sling wire breaks to the limit, the strain δ2 = 1.5δ1 ≤ 0.6%. Assuming the reinforcement length is l1 and the elastic gasket thickness is l2, l2 is set to be greater than 0.001l1. The iron-based shape memory alloy used in the reinforcement typically experiences a contraction strain between 4% and 6% during heating and phase transformation. Therefore, l2 is set to < 0.04l1. In actual design, to mitigate the effects of manufacturing errors and unique stress conditions, the elastic gasket thickness l2 is set within a range of 0.01l1 ≤ l2 ≤ 0.02l1.

[0016] Preferably, the control unit includes a signal transmission module for transmitting the risk level signal to the backend. The signal transmission module can realize remote management and facilitate the implementation of intelligent unmanned management.

[0017] Preferably, it also includes a flexible solar panel, a power storage unit and a power management unit, the flexible solar panel is connected to the power storage unit through the power management unit, the power management unit is connected to the strain detection and control module, the flexible solar panel is wrapped around the columnar connecting frame, and the power storage unit is arranged on the columnar connecting frame and is wrapped by the flexible solar panel.

[0018] Preferably, the shape memory alloy reinforcement rib is a solid cylindrical structure made of one or more alloys selected from the group consisting of Ti-Ni based, Cu-Al-Ti based, Ni-Al based, Fe based, and Cu based.

[0019] Preferably, the surface of the shape memory alloy reinforcement rib is sprayed with a polytetrafluoroethylene coating. The thickness of the polytetrafluoroethylene (PTFE) coating is ≥ 0.05 mm. The polytetrafluoroethylene (PTFE) coating is evenly sprayed onto the surface of the shape memory alloy reinforcement rib by a spraying device.

[0020] The present invention also discloses a temporary reinforcement method for shape memory alloy suspension bridge cables based on strain detection, comprising the following steps:

[0021] S1. Install the columnar connecting frame at both ends of the lower crack;

[0022] S2. Installing a strain gauge on the shape memory alloy reinforcement bar and connecting the strain gauge to a control unit to monitor the strain of the shape memory alloy reinforcement bar in real time;

[0023] S3. Convert the failure condition of the lower end crack into a strain value and define the risk level. The risk level signal is transmitted to the background through the signal transmission module. When the strain limit value is exceeded, the control unit controls the temperature of the shape memory alloy reinforcement bar to increase, and the shape memory alloy reinforcement bar actively contracts to achieve pre-tensioning.

[0024] Preferably, converting the lower end crack failure condition into a strain value and defining the risk level includes:

[0025] Set at least three levels of thresholds, defining levels including at least low risk, medium risk and high risk,

[0026] Regularly calculate the average strain value of multiple shape memory alloy reinforcement bars, compare the average strain value with the threshold value, and perform periodic judgment;

[0027] If the average strain values of adjacent cycles are all low risk, then the risk is considered low;

[0028] If the average strain values of adjacent cycles are not all low risk and only cross one threshold, then it is considered low risk;

[0029] If the average strain values of adjacent cycles are not all low risk and cross a threshold, it is considered to be medium risk;

[0030] If the average strain values of adjacent cycles are all medium risk, then it is considered to be medium risk;

[0031] If one of the average strain values of adjacent cycles is medium risk and the other is high risk, the risk is considered medium;

[0032] If the average strain values of adjacent cycles are all high risk, it is considered high risk;

[0033] If the risk is medium, the power storage unit should be kept fully charged at all times. If the risk is high, the power storage unit should be started to heat all shape memory alloy reinforcement bars.

[0034] The reinforcement device is installed in the broken wire area at the bottom of the sling. The reinforcement principle for the broken wire of the sling is: when the broken wire ratio of the steel wire inside the sling is ≥1 / 3, it is determined that the sling is at risk of breaking. The shape memory alloy reinforcement bar is heated to activate the contraction of the shape memory alloy reinforcement bar for reinforcement.

[0035] Set the radius of the reinforcement bar to r1 and the number to n1. The radius of the reinforcement bar r1 is designed according to the cable tension. In general engineering applications, the safety factor is usually 5 to 6, that is, based on the design bearing capacity calculation, the actual load should not exceed one-fifth or one-sixth of its design bearing capacity. When some of the steel wires inside the sling are broken, the load of the sling will be dispersed to the remaining unbroken steel wires, resulting in an increase in the vertical strain of the sling. Although the bearing capacity of the sling is affected, it may still be able to continue working within a safe range. Under normal circumstances, when the number of broken steel wires exceeds 1 / 3 of the total, the sling will not be able to maintain its design bearing capacity, and there is a risk of possible fracture and failure, and reinforcement is required. Assuming that the cable tension in the service state is F, when 1 / 3 of the steel wires inside the sling are broken, the loss of the cable tension caused by these broken steel wires needs to be borne by the reinforcement bar. The safety factor is set to 5. Since the reinforcement bar with rigid gaskets is fully anchored to the sling after the reinforcement system is installed, it will accumulate damage or even yield under long-term load, resulting in performance degradation and difficulty in assessing its bearing capacity. Therefore, for safety reasons, the bearing capacity of the reinforcement bar with rigid gaskets is not considered when calculating the bearing capacity of the reinforcement bar. Assuming that the yield stress of the shape memory alloy material used in the reinforcement bar is σ1, and the bearing capacity of the rigid reinforcement bar is not considered, the reinforcement bar radius should meet the following requirements:

[0036] After the reinforcement device is installed on the sling, it is fully anchored to the sling through the anchor cup, and the reinforcement bar is anchored to the anchor cup through the anchor ring, thereby reinforcing the sling. If an elastic gasket is installed between the reinforcement bar and the anchor cup, the reinforcement bar and the anchor cup are elastically anchored. When the sling breaks and reinforcement is not initiated, the axial strain increment is offset by the deformation of the elastic gasket, and the reinforcement bar does not bear the vertical axial force from the sling. If a rigid gasket is installed between the reinforcement bar and the anchor cup, the reinforcement bar and the anchor cup are fully rigidly anchored. After the sling breaks, the reinforcement bar and the sling deform synchronously, with the strain being consistent. The rigid anchor reinforcement bar can be used to quantitatively measure the sling strain and determine the internal sling wire breakage.

[0037] A resistance strain gauge was used to measure the strain of rigid anchor reinforcement bars. When a wire breaks inside a cable, the vertical stress state of the cable remains unchanged, but the vertical strain increases. The relationship between the cable strain and the reinforcement strain increment is: assuming the strain before the cable breaks is Δδ1, the strain after the cable reaches failure is Δδ2, and the strain increment between the cable before and after the cable breaks is Δδ. The number of rigid anchor reinforcement bars is two, and their strains are assumed to be Δδ3 and Δδ4, respectively. The cable strain increment is the average of these two values. To reduce strain measurement error and enhance the accuracy of the results, Δδ = 0.5 × (Δδ3 + Δδ4). Compared to manually inspecting and replacing cables, using a resistance strain gauge to measure and determine cable breaks and automatically energize the cable to reinforce the broken wire allows for rapid repair of damaged cables, preventing cable breakage caused by inability to promptly reinforce broken wires, and potentially preventing multiple cables from breaking continuously and potentially leading to bridge failure.

[0038] According to the reinforcement criteria, when 1 / 3 of the steel wires inside the sling are broken, the sling is at risk of failure. Assuming that the elastic modulus of the sling in the initial state without broken wires is E1, the effective cross-section is A1, and the strain δ1=F / E1A1, when there is a risk of cracking, assuming that the effective cross-section of the steel wires inside the sling is A2, At this time, the strain of the sling is δ2, δ2=F / E1(A1-A2)=1.5δ1, and the strain increment before and after the sling is δ2-δ1=0.5δ1.

[0039] When a resistance strain gauge detects a strain increment Δδ ≥ 0.5δ1 in the reinforcement bar, the resistance wire is turned on to heat the reinforcement bar's shape memory alloy to 200°C-250°C, activating the shape memory alloy's memory effect and causing it to actively contract. The contraction strain exceeds the elastic deformation threshold of the spring washer, fully anchoring the reinforcement bar to the sling. Simultaneously, this contraction generates prestress, partially unloading the axial force of the sling onto the reinforcement bar, achieving synergistic force distribution. Conventional reinforcement methods typically involve directly installing reinforcement materials. In the event of a sling wire breakage, differences in stiffness and mechanical properties between the reinforcement material and the original sling result in uneven force distribution. This uneven force distribution can cause localized stress concentrations, increasing the risk of structural failure. Active contraction due to the reinforcement bar's memory effect creates pretension without human intervention, creating a tighter bond between the reinforcement bar and the sling. This allows for even force distribution when the reinforced structure is subjected to tensile loads, achieving synergistic force distribution. This helps enhance the load-bearing capacity and stability of the joint, thereby improving the overall performance of the structure.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] Quick response and temporary repair: The present invention can monitor the strain of the sling in real time. Once the risk of breakage of the sling is detected, the solar power supply module is immediately activated to store energy, and the shape memory alloy reinforcement bar is quickly heated when the strain reaches a critical value, thereby achieving quick temporary repair after the sling fails due to broken wire at the end of the sling, and effectively preventing continuous breakage of the sling caused by the failure of a single sling.

[0042] Automated reinforcement process: Through the strain detection module and control system, the present invention realizes the automation of the reinforcement process. The entire process from detection to reinforcement can be completed without human intervention, greatly improving the reinforcement efficiency and safety.

[0043] Effective synergy: The shape memory alloy reinforcement is securely connected to the sling via anchor cups and rings, allowing it to deform synchronously with the sling, maintaining consistent strain. After reinforcement, the shape memory alloy reinforcement works synergistically with the sling to share the load, effectively improving the overall performance and stability of the sling.

[0044] Efficient solar energy utilization: This invention uses a solar power module to provide electricity for the shape memory alloy reinforcement, achieving green and sustainable energy utilization. Simultaneously, battery energy storage ensures that sufficient electricity is quickly provided for heating when the strain reaches a critical value.

[0045] Preventing current leakage: Insulating gaskets are set at both ends of the shape memory alloy reinforcement bar to effectively prevent the current from flowing from the shape memory alloy to other components when heating, thereby enhancing the current utilization efficiency and ensuring the stability and safety of the reinforcement process.

[0046] In summary, the solar shape memory alloy suspension bridge cable temporary rapid reinforcement system based on strain detection drive of the present invention has multiple beneficial effects such as rapid response, automated reinforcement, and good collaborative working effect. It solves the problems that the existing technology cannot detect the risk of broken wires and breakage of cables, cannot quickly reinforce damaged cables, and the reinforcement device cannot cooperate with the cables to bear force. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0048] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0049] Figure 2 It is a schematic diagram of the local structure of the present invention;

[0050] Figure 3 This is a schematic structural diagram of a columnar connecting frame according to embodiment 2 of the present invention;

[0051] Figure 4 This is a schematic structural diagram of a columnar connecting frame according to embodiment 3 of the present invention;

[0052] Figure 5 It is a schematic structural diagram of a columnar connecting frame according to embodiment 4 of the present invention.

[0053] The description of the accompanying drawings is as follows: 1. sling; 2. lower end crack; 3. upper anchor cup; 4. lower anchor cup; 5. shape memory alloy reinforcement rib; 6. anchor ring; 7. buffer pad; 8. conductive wire; 9. ordinary metal reinforcement rib. DETAILED DESCRIPTION

[0054] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be described in detail below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other implementations obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0055] like Figure 1 and Figure 2 As shown, the temporary reinforcement device for the shape memory alloy suspension bridge sling based on strain detection in this embodiment includes a columnar connecting frame and a control unit. The columnar connecting frame is installed between the sling 1 and the lower end crack 2, and the columnar connecting frame includes:

[0056] Upper anchor cup 3, installed on sling 1;

[0057] The lower anchor cup 4 is installed below the lower end crack 2;

[0058] The shape-memory alloy reinforcement bar 5 is installed on the outside of the sling, with its ends extending parallel to the outside of the upper and lower anchor cups 3 and 4. It is secured by anchor rings 6. The shape-memory alloy reinforcement bar 5 is a solid cylindrical structure made of one or more alloys: Ti-Ni, Cu-Al-Ti, Ni-Al, Fe, or Cu. The surface of the shape-memory alloy reinforcement bar 5 is spray-coated with a polytetrafluoroethylene (PTFE) coating. The PTFE coating has an insulating effect and is applied with a thickness greater than 0.05 mm to extend the service life of the material.

[0059] The control unit is connected to the shape memory alloy reinforcement 5 and is used to detect the strain of the shape memory alloy reinforcement 5 and control the shape memory alloy reinforcement 5. The control unit is connected to the shape memory alloy reinforcement 5 via a conductive wire 8. The control unit includes a signal transmission module for transmitting the risk level signal to the backend.

[0060] When used, the following steps are included:

[0061] S1. Install the columnar connecting frame at both ends of the lower end crack 2;

[0062] S2. Install a strain gauge on the shape memory alloy reinforcement rib 5 and connect the strain gauge to a control unit to monitor the strain of the shape memory alloy reinforcement rib 5 in real time;

[0063] S3. Convert the failure condition of the lower end crack 2 into a strain value and assign a risk level. The risk level signal is transmitted to the backend through the signal transmission module. When the strain limit is exceeded, the control unit controls the temperature of the shape memory alloy reinforcement rib 5 to increase, and the shape memory alloy reinforcement rib 5 actively contracts to achieve pre-tensioning. Determining the risk level includes:

[0064] Set at least three levels of thresholds, and define the levels as at least low risk, medium risk and high risk. Usually three levels are sufficient to meet the use requirements, and the risks can be further subdivided according to the specific requirements of the construction.

[0065] The average strain value of multiple shape memory alloy reinforcement bars 5 is regularly obtained, the average strain value is compared with the threshold value, and a periodic judgment is performed; since there are many external factors causing the strain, effective judgment is required to ensure that it is opened in a timely and accurate manner.

[0066] If the average strain values of adjacent cycles are all low risk, then the risk is considered low;

[0067] If the average strain values of adjacent cycles are not all low risk and only cross one threshold, then it is considered low risk;

[0068] If the average strain values of adjacent cycles are not all low risk and cross a threshold, it is considered to be medium risk;

[0069] If the average strain values of adjacent cycles are all medium risk, then it is considered to be medium risk;

[0070] If one of the average strain values of adjacent cycles is medium risk and the other is high risk, the risk is considered medium;

[0071] If the average strain values of adjacent cycles are all high risk, it is considered high risk;

[0072] If the risk is medium, the power storage unit should be kept fully charged at all times. If the risk is high, the power storage unit should be activated to heat all shape memory alloy reinforcement bars 5. For specific classification levels, please refer to Table 1. Low-risk situations are mainly caused by deformation of the sling itself or strain fluctuations caused by strong winds. Medium-risk situations occur when part of the steel rope in the sling breaks, causing the reinforcement bar to be pulled and strain to be generated. High-risk situations are considered to have reached the limit value and require reinforcement and maintenance of the sling. The average strain threshold can be set to 0.03% for low risk, 0.09% for medium risk, and 0.12% for high risk.

[0073] Table 1 Comparison of risk level judgments

[0074] Previous average risk The latter average risk situation Sling risk level Low risk Low risk Low risk Low risk Medium risk Low risk Low risk High risk Medium risk Medium risk Medium risk Medium risk Medium risk High risk Medium risk Medium risk Low risk Low risk High risk Low risk Medium risk High risk Medium risk Medium risk High risk High risk High risk

[0075] Example 1

[0076] like Figure 1 and 2 As shown, in this embodiment, all the reinforcing ribs are made of shape memory alloy reinforcing ribs 5, and the control unit includes a direct power supply heating module, which is arranged at both ends of the shape memory alloy reinforcing ribs 5. Heating and temperature rise are achieved by energizing the shape memory alloy reinforcing ribs 5, and reinforcement is achieved through shrinkage and deformation.

[0077] Example 2

[0078] like Figure 3 As shown, in this embodiment, there are two types of reinforcement bars, namely ordinary metal reinforcement bars 9 and shape memory alloy reinforcement bars 5, which are arranged crosswise between the upper anchor cup 3 and the lower anchor cup 4. This arrangement can reduce the use of shape memory alloy while ensuring the use effect and reducing costs.

[0079] Example 3

[0080] like Figure 4 As shown, in this embodiment, the sling is also equipped with a middle anchor cup. Specifically, a shape memory alloy reinforcement bar 5 is installed between the upper and middle anchor cups, and a conventional metal reinforcement bar 9 is installed between the middle and lower anchor cups. The shape memory alloy reinforcement bar 5 and the conventional metal reinforcement bar 9 are installed in a stacked manner. Since cracks may be longer in size, the cost of using long memory alloys is high. Therefore, a combination of conventional reinforcement bars and shape memory alloys can be used to ensure effective use and reduce costs.

[0081] Example 4

[0082] like Figure 5 As shown, in this embodiment, a heating wire 10 is arranged outside the shape memory alloy reinforcement rib 5, and the heating wire 10 is spirally wound outside the shape memory alloy reinforcement rib 5. The cost of using electric heating of shape memory alloy is relatively high, so an external heating wire 10 is used to heat the shape memory alloy.

[0083] When the reinforcement bar in the above embodiment is installed, a buffer pad 7 should be included. The buffer pad 7 is sleeved on the reinforcement bar and supported between the anchor ring 6 and the anchor cup. The buffer pad 7 can be used for both buffering and insulating functions.

[0084] Example 5

[0085] In the prior art, the control unit is primarily powered by wiring, combined with battery power. For ease of use, some installation areas utilize solar panels for charging, reducing wiring. However, when installed within bridge cables, the required wind resistance is high, and conventional solar panels cannot guarantee safe use. Therefore, in this embodiment, a solar power module is used for power supply. The solar power module includes a flexible solar panel, a power storage unit, and a power management unit. The flexible solar panel is connected to the power storage unit via the power management unit, which is in turn connected to the strain detection and control module. The flexible solar panel is wrapped around a columnar connecting frame, and the power storage unit is mounted on the columnar connecting frame and enclosed by the flexible solar panel. Because the contraction of the reinforcement bar can cause the anchor cup to move, the fixed method between them cannot ensure effective installation of the solar panel. A redundant structure (here, the redundant structure means that the solar panel should move with the contraction of the reinforcement bar to avoid hard impact) is required to ensure that the flexible solar panel is not damaged by the movement of the anchor cup. The flexible solar panel is made of resin-encapsulated amorphous silicon as the main photovoltaic layer, laid flat on a flexible base plate. Its characteristics are: bendability and foldability. The solar panel can be wrapped around the outside of the columnar connecting frame, and the battery can be installed inside the columnar connecting frame. On the one hand, it can block sunlight and prevent direct sunlight from hitting the battery, ensuring the safety of battery use. On the other hand, the columnar solar receiver can receive solar energy from multiple directions without adding extra volume, effectively ensuring safety of use.

[0086] When the sling level reaches medium risk, ensure that the battery is fully charged and stop all other power supplies to ensure sufficient heating of the reinforcement. When the risk reaches high risk, heating is immediately started. For ease of use, a temperature sensor should be installed to stop heating when the temperature reaches the set point.

[0087] The present invention anchors the shape memory alloy reinforcement bar to the sling through an anchor cup and an anchor ring, utilizes the strain of the shape memory alloy reinforcement bar to detect broken wires inside the sling, utilizes a solar power supply module to energize the shape memory alloy reinforcement bar, utilizes the shape memory characteristics of the shape memory alloy to realize active contraction when energized and heated to reinforce the broken wire sling, and arranges insulating gaskets at the upper and lower ends to prevent the current from flowing from the shape memory alloy to other components when the shape memory alloy is energized and heated, thereby enhancing the current utilization efficiency. On the one hand, the present invention realizes rapid temporary repair of cracks at the end of the sling, and on the other hand, the reinforcement process is automatically completed, and the sling works well in coordination with the reinforcement.

[0088] Within the technical scope disclosed by the present invention, any changes or substitutions that can be easily imagined should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A temporary reinforcement device for shape memory alloy suspension bridge cables based on strain detection, characterized in that: The invention comprises a columnar connecting frame and a control unit, wherein the columnar connecting frame is installed between the sling (1) and the lower end crack (2), and the columnar connecting frame comprises: an upper anchor cup (3) mounted on the sling (1); A lower anchor cup (4) is installed below the lower end crack (2); A shape memory alloy reinforcing rib (5) is arranged on the outside of the sling, with both ends in the length direction extending parallel to the outside of the upper anchor cup (3) and the lower anchor cup (4), and is fixed by an anchor ring (6); The control unit is connected to the shape memory alloy reinforcement rib (5) and is used for detecting the strain of the shape memory alloy reinforcement rib (5) and controlling the shape memory alloy reinforcement rib (5).

2. The temporary reinforcement device for shape memory alloy suspension bridge cables based on strain detection according to claim 1 is characterized in that: It also includes ordinary metal reinforcement ribs (9) which are arranged together with the shape memory alloy reinforcement ribs (5) between the upper anchor cup (3) and the lower anchor cup (4).

3. The temporary reinforcement device for shape memory alloy suspension bridge cables based on strain detection according to claim 1 or 2, characterized in that: The control unit comprises a direct power supply heating module or an indirect power supply heating module, wherein the direct power supply heating module is arranged at both ends of the shape memory alloy reinforcement rib (5) and heats the shape memory alloy reinforcement rib (5) by energizing the module; and the indirect power supply heating module is arranged around the shape memory alloy reinforcement rib (5).

4. The temporary reinforcement device for shape memory alloy suspension bridge cables based on strain detection according to claim 3 is characterized in that: It also includes a buffer pad (7), which is sleeved on the shape memory alloy reinforcement rib (5) and is respectively arranged between the shape memory alloy reinforcement rib (5) and the upper anchor cup (3) and the lower anchor cup (4).

5. The temporary reinforcement device for suspension bridge cables of a shape memory alloy based on strain detection according to claim 4 is characterized in that: The control unit includes a signal transmission module for transmitting the risk level signal to the background.

6. The temporary reinforcement device for suspension bridge cables of a shape memory alloy based on strain detection according to claim 5 is characterized in that: It also includes a flexible solar panel, a power storage unit and a power management unit. The flexible solar panel is connected to the power storage unit through the power management unit. The power management unit is connected to the strain detection and control module. The flexible solar panel is wrapped around the columnar connecting frame. The power storage unit is arranged on the columnar connecting frame and is wrapped by the flexible solar panel.

7. The temporary reinforcement device for shape memory alloy suspension bridge cables based on strain detection according to claim 6 is characterized in that: The shape memory alloy reinforcement rib (5) is a solid cylindrical structure made of one or more alloys selected from the group consisting of Ti-Ni based, Cu-Al-Ti based, Ni-Al based, Fe based, and Cu based.

8. The temporary reinforcement device for suspension cables of a shape memory alloy suspension bridge based on strain detection according to claim 7 is characterized in that: The surface of the shape memory alloy reinforcement rib (5) is sprayed with a polytetrafluoroethylene coating.

9. A temporary reinforcement method for a shape memory alloy suspension bridge cable based on strain detection, based on the temporary reinforcement device for a shape memory alloy suspension bridge cable based on strain detection as claimed in claim 8, characterized in that: The following steps are involved: S1, installing the columnar connecting frame at both ends of the lower end crack (2); S2, installing a strain gauge on the shape memory alloy reinforcement bar (5), and connecting the strain gauge to a control unit to monitor the strain of the shape memory alloy reinforcement bar (5) in real time; S3. The failure condition of the lower end crack (2) is converted into a strain value, and a risk level is defined. The risk level signal is transmitted to the backend through the signal transmission module. When the strain limit value is exceeded, the control unit controls the shape memory alloy reinforcement bar (5) to heat up, and the shape memory alloy reinforcement bar (5) actively contracts to achieve pre-tensioning.

10. The temporary reinforcement method for shape memory alloy suspension bridge cables based on strain detection according to claim 9, characterized in that: The conversion of the failure condition of the lower end crack (2) into a strain value and the determination of the risk level include: Set at least three levels of thresholds, defining levels including at least low risk, medium risk and high risk, Regularly obtaining an average strain value of a plurality of shape memory alloy reinforcement bars (5), comparing the average strain value with a threshold value, and performing a periodic judgment; If the average strain values of adjacent cycles are all low risk, then the risk is considered low; If the average strain values of adjacent cycles are not all low risk and only cross one threshold, then it is considered low risk; If the average strain values of adjacent cycles are not all low risk and cross a threshold, it is considered to be medium risk; If the average strain values of adjacent cycles are all medium risk, then it is considered to be medium risk; If one of the average strain values of adjacent cycles is medium risk and the other is high risk, the risk is considered medium; If the average strain values of adjacent cycles are all high risk, it is considered high risk; If the risk is medium, the power storage unit should be kept in a fully charged state at all times. If the risk is high, the power storage unit should be started to heat all the shape memory alloy reinforcement bars (5).

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