Data-fidelity in-service distributed optical fiber sensor repairing device and method

Abstract

The invention discloses a data-fidelity in-service distributed optical fiber sensor repairing device and method, and relates to the technical field of structural health monitoring. The device comprises a fixed support, a supporting arm, a scaleplate with scales and a slidable optical fiber clamping piece, the fixed support is installed on the surface of a structure to provide a stable base, and the ruler is connected with the supporting arm and used for finely adjusting the distance between the optical fiber clamping pieces and controlling optical fiber tension. The method comprises the steps of positioning and cleaning a breakpoint, installing a device, clamping an optical fiber, welding and repairing, adjusting the distance of a clamping piece so as to accurately match the initial strain value of the optical fiber before repairing, and finally packaging and curing by adopting the thickness of epoxy resin which is theoretically designed so as to ensure that the strain transfer characteristic of a repaired section is consistent with that of an original sensor. According to the method, the problem that the data quality cannot be guaranteed due to the fact that only an optical path is restored in a traditional restoration mode is solved, continuity and accuracy of monitored data of a restoration section are achieved through a special device and a quantification process, and the reliability of long-term operation of an in-service distributed optical fiber sensing system is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of structural health monitoring technology, specifically a distributed optical fiber sensor repair technology, and a data-fidelity in-service distributed optical fiber sensor repair device and method. Background Technology

[0002] Distributed fiber optic sensors, with their unique advantages such as distributed measurement, resistance to electromagnetic interference, and high durability, have been widely used in the field of structural health monitoring in civil engineering, especially in the long-term service performance and safety monitoring of large infrastructure. They can achieve continuous spatial and synchronous temporal sensing of multiple parameters such as strain and temperature along the fiber optic path, providing an irreplaceable technical means for assessing the overall and local conditions of a structure. However, in long-term, complex, and harsh service environments, pre-embedded or surface-mounted distributed fiber optic sensors are highly susceptible to accidental damage or breakage. Such damage leads to interruptions in monitoring data, creating monitoring blind spots and severely weakening the integrity and reliability of the health monitoring system. Currently, on-site repair of broken distributed fibers typically employs simple fiber optic splicing and temporary fixation with tape. While these methods can restore the physical connectivity of the optical path, they have significant drawbacks: First, the initial strain state of the optical fiber is difficult to control precisely during the repair process, resulting in inconsistencies between the initial strain value of the sensor in the repaired section and that before the breakage, thus disrupting the historical continuity of the monitoring data. Second, the temporary fixing method cannot guarantee a stable and reliable strain transfer interface between the sensor in the repaired section and the structure, and its strain transfer characteristics often differ from those of the original sensor section, causing the strain value measured in the repaired section to fail to accurately reflect the structural deformation, resulting in data distortion.

[0003] Therefore, existing technologies lack a standardized repair process and device that can be implemented on-site to ensure that the repaired distributed fiber optic sensor not only restores signal transmission but also inherits the structural deformation data from before the repair, maintaining the consistency of the sensor's deformation transmission characteristics—that is, achieving data-fidelity repair. This problem limits the full realization of the potential of distributed fiber optic monitoring technology in long-lifecycle infrastructure health monitoring. While numerous fiber optic sensor repair technologies have been published, no in-service distributed fiber optic sensor repair devices or methods claiming to provide data fidelity have been found. Some publicly available related solutions are listed below:

[0004] Chinese Patent CN121049289A discloses an integrated monitoring and repair fiber optic sensing system and its usage method. Based on data from the integrated monitoring and repair module and analysis from the repair evaluation module, it achieves closed-loop control from crack detection and repair to effect evaluation. Chinese Patent CN106998226B discloses an intelligent health monitoring and self-repair system and method for fiber optic grating sensor networks. It uses surviving fiber optic grating sensors near the damaged area as a basis to compensate for the function of failed sensors. Chinese Patent CN116086533A discloses a self-repairing concrete structure health monitoring system and method. It uses a BIM structural model to more intuitively display the damage to structural parts and the repair effect in a self-repairing state. Chinese Patent CN116683985A discloses a fault detection and repair method for a fiber optic sensor network based on a star-ring topology. It can detect and locate sensor faults when there is no link failure in the fiber optic sensor network, and can also achieve network self-repair after a fiber optic link failure. However, most of the aforementioned technologies do not address the issue of data fidelity after fiber optic sensor repair, nor do they propose that data fidelity involves not only strain data inheritance but also the consistency of strain transfer characteristics. Therefore, there is an urgent need for an in-service distributed fiber optic sensor repair device and method that ensures data fidelity, enabling standardized on-site repair throughout the entire process, from fixture fine-tuning and resetting, initial strain value matching to encapsulation interface reconstruction, thus guaranteeing the continuity, consistency, and long-term reliability of monitoring data. Summary of the Invention

[0005] The purpose of this invention is to provide a data-fidelity-preserving in-service distributed optical fiber sensor repair device and method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A data-fidelity in-service distributed fiber optic sensor repair device is characterized by comprising a fixed support and a support arm, wherein the fixed support is connected to a structural surface for fixing the fiber optic sensor repair device on the structural surface.

[0008] Preferably, the bottom of the fixed support is provided with a magnetic adsorption layer or a vacuum suction cup, which is suitable for metal or smooth non-metallic structural surfaces, enabling quick and non-destructive installation and disassembly.

[0009] Preferably, the fixed support is permanently connected to the structural surface by chemical anchors or high-strength adhesives, suitable for rough concrete or masonry surfaces, ensuring stability during the repair process.

[0010] Preferably, the support arm is a multi-section telescopic sleeve structure or a hinged robotic arm structure, which can achieve flexible adjustment of length and angle with multiple degrees of freedom to adapt to repair operations in different spatial positions.

[0011] Furthermore, the support arm is connected to a scale, on which a sliding fiber optic clip is provided to clamp both ends of the fiber optic sensor to be repaired. The scale is provided with graduations to fine-tune the distance between adjacent fiber optic clips and to adjust the tension of the fiber optic cable.

[0012] Preferably, the scale is a high-precision scale and is equipped with a digital reading display, which can improve the displacement adjustment accuracy of the fiber optic clip to the level of 0.1 mm.

[0013] Preferably, the scale is coated with fluorescent or luminescent material and has physical positioning slots at key distance positions to facilitate quick and accurate coarse and fine adjustments in low-light environments.

[0014] A method for repairing an in-service distributed fiber optic sensor with data fidelity, characterized in that the method includes:

[0015] S1. Based on the effective sensing distance of the fiber optic sensing device, locate the break point of the distributed fiber optic cable and remove any residual adhesive from the distributed fiber optic sensor at the break point.

[0016] S2. Fix the fixed support to the structural surface near the fiber break point, and adjust the direction of the support arm to be consistent with the cabling direction of the distributed fiber.

[0017] S3. Secure the two ends of the broken optical fiber with optical fiber clips and repair the broken optical fiber with new optical fiber.

[0018] S4. After the fiber optic cable has been repaired, reconnect the fiber optic sensing device and adjust the distance of the fiber optic clips to make the initial strain value of the fiber optic sensor consistent with that before the fiber optic cable was disconnected.

[0019] S5. Distributed fiber optic sensor repaired by fixing with epoxy resin.

[0020] Preferably, in step S1, a low-temperature spray can be applied to the residual adhesive to make it brittle before gently scraping it off, so as to avoid thermal or mechanical damage to the surface of the structural substrate and the intact optical fiber coating nearby.

[0021] Preferably, in step S1, a special solvent that matches the composition of the adhesive is used for local impregnation and softening, followed by wiping with a lint-free cloth to remove it. This method has minimal impact on the substrate surface.

[0022] Preferably, in step S3, the repair is performed using a fiber optic fusion splicer, with the splice point located at the center between the two fiber clips. After splicing, the splice point needs to be reinforced with heat shrink tubing for protection.

[0023] Preferably, in step S3, when fusion splicing is not possible on-site, the repair is performed using a high-performance fiber optic mechanical connector, which must have low insertion loss and good tensile strength.

[0024] Preferably, in step S3, before splicing or connecting, the two end faces of the disconnected fiber are inspected and cleaned using a fiber end face inspection instrument to ensure that the end face quality meets the requirements, thereby reducing connection loss.

[0025] Preferably, in step S4, before adjusting the distance between the fiber clips, the real-time strain value of at least 1 meter of intact fiber optic segment near the repair point is read by a distributed fiber optic sensing device, and its average value is used as the initial target strain value for matching and adjustment.

[0026] Preferably, during the adjustment process, the strain change curve of the repair section displayed by the distributed optical fiber sensing device is monitored in real time, and the curve is shifted to a position level with the strain baseline of the adjacent intact section by fine-tuning the distance between the optical fiber clips.

[0027] Furthermore, the data fidelity specifically refers to the fact that the repaired distributed optical fiber inherits the structural deformation data before repair and maintains consistency with the sensor deformation transmission characteristics.

[0028] Preferably, the data fidelity also includes the consistency of temperature sensing characteristics, that is, the temperature sensing coefficient of the repaired fiber should be consistent with that of the original fiber, or corrected by a calibration formula, to ensure the accuracy of temperature compensation.

[0029] Furthermore, the distributed optical fiber inherits the structural deformation data before repair, specifically the average strain of the repaired segment L. Average strain of the corresponding segment before repair Consistency, that is .

[0030] Preferably, the average strain of the corresponding segment before repair is... The calculated value is taken from the corresponding position L segment in the last set of valid distributed strain data before the fiber optic cable breaks.

[0031] Preferably, if historical strain data is unavailable or unreliable, the current average strain of a corresponding length segment of another intact optical fiber located in the same stress region and symmetrical to the repaired segment is measured and calculated as [the average strain]. Alternative reference values.

[0032] Preferably, when the structure is under complex stress, the theoretical average strain of the repair segment L under load conditions at the fracture moment can be simulated and calculated using a finite element model, as... The engineering estimate is used for matching.

[0033] Furthermore, the consistency of the deformation transfer characteristics of the distributed optical fiber sensors specifically refers to the average strain transmissibility of the optical fiber sensors in the repaired segment L. Compared to before repair Consistency, that is .

[0034] Preferably, when the repair fiber is the same type as the original fiber, the change in the deformation transmission characteristics of the distributed fiber optic sensor can be ignored. However, if the type, ratio, or curing process of the epoxy resin used during repair differs from the original process, further adjustments are still required. Conduct actual measurements or evaluations.

[0035] As a preferred option, after the repair section is sealed and cured, a local micro-strain loading device is used for on-site calibration testing to directly measure its actual strain transfer rate and compare it with the design value as the final acceptance step.

[0036] Furthermore, when reinforced or armored optical fibers are used to strengthen weak points, the average strain transmissibility of the fiber optic sensor in the repair area should be calculated using shear hysteresis theory. While ensuring consistent average strain transmissibility, the thickness of the epoxy resin should be redesigned, establishing the following equation:

[0037]

[0038] in, and It is the shear hysteresis coefficient of the fiber optic sensor before and after repair, used to measure the strain transfer characteristics of the sensor. and This refers to the shear modulus of the epoxy resin before and after the repair of the fiber optic sensor. and This refers to the elastic modulus of the epoxy resin before and after the repair of the fiber optic sensor. and This refers to the thickness of the epoxy resin before and after the repair of the fiber optic sensor. and It refers to the radius of the optical fiber before and after the repair of the optical fiber sensor.

[0039] Furthermore, ensuring the consistency of deformation transmission characteristics of the distributed optical fiber sensor specifically refers to using shear hysteresis theory to back-calculate the required epoxy resin thickness.

[0040] Preferably, the back calculation process is an iterative optimization process, with the epoxy resin thickness as the variable and minimizing the error between the calculated ASTR^' and the target ASTR as the objective function, and the optimal thickness is solved by numerical methods.

[0041] Preferably, considering the shrinkage of epoxy resin during the curing process, the theoretical thickness obtained through back-calculation is... Based on this, a compensation margin is added according to the shrinkage rate of the resin, which is used as the actual construction thickness.

[0042] As a preferred approach, the back calculation not only considers the consistency of the average strain transfer rate, but also further considers the strain transfer efficiency at both ends of the repair section and the smooth transition with the intact section, and designs the epoxy resin thickness in a gradient manner.

[0043] Furthermore, when the length of the repair segment L is greater than 100mm, the equality relationship between the shear hysteresis coefficients can be directly established, as shown in the following equation:

[0044]

[0045] With other variables known, only One required quantity is the thickness of the epoxy resin to be applied after repair.

[0046] Furthermore, if the properties of the epoxy resin can be kept consistent, the quantitative relationship between the shear hysteresis coefficients can be simplified to the following equation:

[0047]

[0048] Furthermore, when using thinner optical fibers, or bare optical fibers, the quantitative relationship between the shear hysteresis coefficients can be further simplified to the following equation:

[0049]

[0050] Preferably, the 100mm threshold is a simplified engineering critical value obtained after extensive simulation analysis based on typical sensing fiber and epoxy resin parameters. For ultra-long repair sections (such as L>500mm), this simplified method has higher accuracy.

[0051] As a preferred option, for short repair segments less than 100mm in length, the complete ASTR equation must be used for accurate calculation and design, and the simplified condition of equal shear hysteresis coefficient λ cannot be used.

[0052] The technical effects and advantages of this invention are as follows:

[0053] 1. This invention proposes a complete set of data fidelity restoration theory and standardized field process, which ensures the historical continuity and long-term reliability of monitoring data in the restored section, and solves the problems of data distortion and reduced monitoring value caused by traditional simple restoration.

[0054] 2. The specialized repair device designed in this invention provides a stable and quantifiable operating platform for on-site repair through a combination of a fixed support, a graduated scale, and a sliding fiber optic clip. This device has a simple structure, is easy to carry, and can be quickly installed on various structural surfaces. It enables precise tensioning and displacement control of the optical fiber, providing crucial hardware support for accurately reproducing the initial strain value of the optical fiber and solving the problem of lacking precise adjustment methods on-site.

[0055] 3. The strain initial value matching method proposed in this invention, by combining the fine-tuning function of the repair device with the real-time feedback of the distributed sensing device, realizes the visualization and precise setting of the initial strain of the repair section, avoids the introduction of false strain or data jumps due to repair, and ensures the consistency of long-term monitoring data curves.

[0056] 4. This invention introduces a shear hysteresis theory model to guide the repair packaging design, especially for repair scenarios using different types of optical fibers. By establishing a mathematical model and back-calculating the required epoxy resin thickness, the strain transfer characteristics of the repair section can be actively designed and controlled to ensure its consistency with the original sensor section.

[0057] 5. The overall solution of this invention fully considers the convenience of on-site engineering implementation and provides differentiated solutions for different repair scenarios. The entire solution is highly tool-based and standardized, making it easy for on-site technicians to master and apply. Attached Figure Description

[0058] Figure 1 A schematic diagram of the in-service distributed optical fiber sensor repair device for data fidelity according to the present invention.

[0059] Figure 2 This is a schematic diagram of the repair device of the present invention attached to a broken fiber.

[0060] Figure 3 This is a schematic diagram of the repaired surface fiber optic sensor of the present invention.

[0061] Figure 4 This is a schematic diagram of the fiber optic sensor with its surface repaired and re-attached with epoxy resin according to the present invention.

[0062] Figure 5 A flowchart of the in-service distributed optical fiber sensor repair method for ensuring data fidelity according to the present invention.

[0063] In the diagram: 1. Fixed support; 2. Support arm; 3. Scale; 4. Fiber optic clip; 5. Disconnected fiber optic cable; 6. New fiber optic cable; 7. Epoxy resin. Detailed Implementation

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] It should be understood that the distributed optical fiber sensing technology and optical fiber fusion splicing technology used in this invention are based on principles, structures, and manufacturing methods that are common knowledge in the field. The optical fiber sensing technology involved in the embodiments of this invention is not the innovation of this invention, nor is it the content claimed in this patent.

[0066] First Embodiment

[0067] For scenarios with harsh environments and limited space, such as the interior of box girders of in-service long-span bridges, underwater structures, or highly corrosive industrial plants, this embodiment details an adaptive method and key operating parameters for repair using the device of the present invention.

[0068] (1) Before repair, use an endoscope to explore the inside of the box girder or enclosed space such as the pipe gallery to confirm the location of the break, the size of the space and the condition of the structural surface. If there is rust or laitance on the surface, use an angle grinder with a wire brush to clean it locally to expose the solid substrate.

[0069] (2) On damp or condensed steel structures, the magnetic adsorption function of the fixed support (1) should be used first. To ensure that there are no problems, after adsorption, an additional ring of quick-drying underwater epoxy glue can be applied to the edge of the support to assist in fixation. Adjust the length of the support arm (2) so that the axis of the scale (3) is strictly parallel to the original optical fiber direction for at least 0.5 meters on both sides of the break point, and the deviation is controlled within ±2°.

[0070] (3) Before fiber optic splicing, a new end face must be made on both sides of the break point using a special fiber optic cleaver and cleaned with high-purity anhydrous ethanol and lint-free paper. The splice point should be selected at the center of the two fiber clips (4) at equal distances. After splicing, immediately apply double protection to the splice point: the first layer is heat shrink tubing, and the second layer is a stainless steel reinforced armor tube, and press it with special hydraulic clamps to resist mechanical and chemical corrosion in harsh environments.

[0071] (4) Reconnect the distributed fiber optic sensing device. After the readings stabilize, observe the strain distribution curves within a 2-meter range upstream and downstream of the break point. By finely adjusting the sliders of the two fiber clips (4), change the tension of the repair section. The goal is to make the strain distribution curve of the repair section continuous with the upstream and downstream curves, without any steps or inflections. Record the displacement adjustment amount Δd displayed by the slider at this time. This Δd is the mechanical adjustment amount for achieving strain inheritance.

[0072] Second Embodiment

[0073] This embodiment focuses on steps S4 (strain initial value matching) and S5 (encapsulation design) of the method, and demonstrates in detail the complete quantitative process from data reading and theoretical calculation to encapsulation construction, especially the application of shear lag theory.

[0074] (1) Assume the design length of the repair section is L = 150 mm. Using a distributed sensing device, read and export the strain data ε of the 100 mm section from 50 mm upstream to 50 mm downstream of the repair location in the last set of valid data before the break point. i (i=1…n). Calculate their average value:

[0075]

[0076] The average reference strain before repair The strain of the repaired fiber optic access system initially exhibited as ε. init By adjusting the distance between the fiber optic clips, the average new strain of the repaired segment L can be displayed in real time by the sensing device. Approaching The criterion is:

[0077]

[0078] (2) Packaging design guided by shear hysteresis theory: Assume the original fiber is a standard 250μm coated fiber, and it is repaired to a reinforced 900μm tight-buffered armored fiber. Known parameters:

[0079] Before repair: E f =72GPa, r f =0.125mm, G p =1.2GPa, r p =1.25mm.

[0080] After repair: E f =72GPa, r f =0.45mm, G p =1.2GPa (using the same epoxy resin), repair section length L =150 mm > 100 mm.

[0081] Objective: To maintain consistent strain transfer characteristics, i.e. .

[0082] (3) Calculation process:

[0083] Substitute into the simplified formula:

[0084] because The formula simplifies to:

[0085]

[0086] Substituting the values, we get ≈0.5375mm

[0087] (4) Based on the calculation results, the thickness of the epoxy resin after repair should be approximately 0.54 mm. Therefore, a U-shaped silicone rubber mold was designed, with a groove width slightly larger than the diameter of the armored optical fiber. The strain-matched optical fiber segment was placed into the mold groove, and low-viscosity, high-toughness epoxy resin was injected using a syringe to ensure full filling. After curing, the mold was removed, forming a dimensionally controlled encapsulation.

[0088] Third Embodiment

[0089] This embodiment extends the method of the present invention to a preventive maintenance and proactive data inheritance scenario, namely, to pre-repair distributed optical fiber segments that have not yet completely broken but have already shown obvious damage or attenuation.

[0090] (1) By analyzing long-term monitoring data, it was found that the signal-to-noise ratio of a certain fiber optic segment continued to decline, local strain data showed abnormal jumps, or there were points of sudden increases in microbending loss. It was determined that the fiber optic segment had hidden damage and was at risk of breaking. Based on the importance of the structure, it was decided to carry out preventive repairs before the breakage.

[0091] (2) Since the optical fiber is not yet broken, the traditional clamping fusion splicing method is not applicable. A "bypass welding" scheme is adopted. First, using the device of this invention, a new optical fiber (6) is laid parallel to the damaged section. The two ends of the new optical fiber are temporarily fixed by optical fiber clips (4), and its tension is adjusted so that its average strain value is consistent with the current average strain value of the damaged section, thereby realizing "data inheritance pre-matching". Then, at both ends of the damaged section, optical fiber couplers or welding points are used to switch the signal from the old optical fiber (5) to the new optical fiber (6). After the switching is completed, the damaged section optical fiber is removed.

[0092] (3) During pre-repair, there is sufficient time to optimize the encapsulation design. For example, the original damaged section is located in a high-stress area, and the encapsulation layer already has microcracks. In the encapsulation design of the new optical fiber (6), in addition to ensuring ASTR consistency, epoxy resin with higher shear modulus and better toughness can be actively selected, and the encapsulation thickness can be appropriately increased to improve the durability of the repaired section in subsequent service. At the same time, theoretical calculations can be used to ensure .

Claims

1. A data-fidelity-preserving in-service distributed fiber optic sensor repair device, characterized in that, It includes a fixed support (1) and a support arm (2), wherein the fixed support (1) is connected to the surface of the structure and is used to fix the fiber optic sensor repair device on the surface of the structure; The support arm (2) is connected to the scale (3). A sliding fiber clip (4) is provided on the scale (3) to clamp the two ends of the fiber sensor to be repaired. The scale (3) is provided with a scale to finely adjust the distance between adjacent fiber clips (4) and adjust the tension of the fiber.

2. A method for repairing an in-service distributed optical fiber sensor with data fidelity, characterized in that, The method includes: S1. Based on the effective sensing distance of the fiber optic sensing device, locate the break point of the distributed fiber optic cable and remove any residual adhesive from the distributed fiber optic sensor at the break point. S2. Fix the fixed support (1) on the structural surface near the fiber break point, and adjust the direction of the support arm (2) to make it consistent with the wiring direction of the distributed fiber. S3. Secure the two ends of the broken optical fiber (5) with optical fiber clips (4) and repair the broken optical fiber (5) with new optical fiber (6); S4. After the disconnected optical fiber (5) is repaired, the optical fiber sensing device is reconnected. By adjusting the distance of the optical fiber clip (4), the initial strain value of the optical fiber sensor is made consistent with that before the optical fiber was disconnected. S5. The repaired distributed optical fiber sensor is fixed with epoxy resin (7).

3. The data-fidelity-preserving in-service distributed optical fiber sensor repair method according to claim 2, characterized in that, The data fidelity specifically refers to the fact that the repaired distributed optical fiber inherits the structural deformation data before repair and has consistent sensor deformation transmission characteristics. The distributed optical fiber inherits the structural deformation data before repair, specifically the average strain value of the repaired segment L. Average strain of the corresponding segment before repair Consistency, that is ; The consistency of the deformation transfer characteristics of the distributed optical fiber sensors specifically refers to the average strain transmissibility of the optical fiber sensors in the repaired segment L. Compared to before repair Consistency, that is .

4. The data-fidelity-preserving in-service distributed optical fiber sensor repair method according to claim 2, characterized in that, To ensure the consistency of the deformation transmission characteristics of the distributed optical fiber sensor, when the repair optical fiber is of the same type as the initial optical fiber, the change in the deformation transmission characteristics of the distributed optical fiber sensor can be ignored. When reinforced or armored optical fibers are used to strengthen weak points, the average strain transmissibility of the fiber optic sensor in the repair area should be calculated using shear hysteresis theory. While ensuring consistent average strain transmissibility, the thickness of the epoxy resin should be redesigned, and the following equation should be established: in, and It is the shear hysteresis coefficient of the fiber optic sensor before and after repair, used to measure the strain transfer characteristics of the sensor. and This refers to the shear modulus of the epoxy resin before and after the repair of the fiber optic sensor. and This refers to the elastic modulus of the epoxy resin before and after the repair of the fiber optic sensor. and This refers to the thickness of the epoxy resin before and after the repair of the fiber optic sensor. and It refers to the radius of the optical fiber before and after the repair of the optical fiber sensor.

5. The data-fidelity-preserving in-service distributed optical fiber sensor repair method according to claim 2, characterized in that, Ensuring the consistency of deformation transmission characteristics of distributed optical fiber sensors specifically refers to using shear hysteresis theory to back-calculate the required epoxy resin thickness.

6. The data-fidelity-preserving in-service distributed optical fiber sensor repair method according to claim 2, characterized in that, To ensure the consistency of deformation transmission characteristics of the distributed optical fiber sensor, when the length of the repair segment L is greater than 100mm, an equal relationship between the shear hysteresis coefficients can be directly established, as shown in the following equation: With other variables known, only One required quantity is the thickness of the epoxy resin to be applied after repair.

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