High-temperature-resistant anti-biting composite sensing optical cable and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant and anti-biting composite sensing optical cable and a preparation method thereof. The optical cable comprises a sensing optical fiber unit, a stress decoupling buffer layer, a composite tensile enhancement layer, a bionic synergistic protection layer and a weather-resistant outer sheath from inside to outside, the outer surface of the sensing optical fiber unit is provided with micro-bulge structures which are regularly distributed, and the micro-bulge structures are embedded into the stress decoupling buffer layer to form a three-dimensional discrete supporting interface; the bionic synergistic protection layer comprises an inner barrier layer, a function release layer and an outer restraint layer which are sequentially arranged from inside to outside; the function release layer is a composite material layer with internal and external functional gradients; and the outer restraint layer is a tubular grid formed by weaving shape memory alloy wires. The optical cable provided by the invention can simultaneously meet the strict requirements of a high-voltage transmission line on long-term operation in an ultra-wide temperature range, triple bionic cooperative active bite prevention, high-precision sensing signal stability and ultra-long environmental life, and realizes long-term reliability and accuracy of distributed monitoring in an extremely complex environment.

Description

Technical Field

[0001] This invention relates to the field of special optical fiber and cable technology, and in particular to a high-temperature resistant and anti-biting composite sensing optical cable and its preparation method. Background Technology

[0002] Distributed temperature, strain, and vibration monitoring of high-voltage transmission lines is crucial for ensuring power grid safety. This type of monitoring relies on sensing optical cables attached to conductors or independently installed. However, existing sensing optical cables still have systemic shortcomings when dealing with long-term short-circuit faults, complex mechanical stresses, wild animal bites, and harsh climatic environments, making it difficult to meet the monitoring requirements for high reliability and long lifespan. Specifically: Insufficient high-temperature resistance and long-term thermal stability: Traditional optical cables commonly use polyethylene, polyvinyl chloride, or ordinary aramid as sheathing or reinforcing materials, with long-term operating temperatures typically below 150℃. When the conductor experiences overload or short-circuit faults, the instantaneous high temperature can easily cause these materials to soften, melt, or even thermally decompose, resulting in permanent failure of the optical cable structure and monitoring interruption. While some solutions using glass fiber or stainless steel strip reinforcement provide some mechanical protection, their organic adhesives or supporting structural materials remain weak points when facing sustained high temperatures, raising concerns about long-term thermal aging performance.

[0003] Anti-gnawing mechanisms are simplistic and have limited effectiveness: To resist the gnawing of animals such as rats and ants, existing technologies mostly rely on passive physical protection such as increasing the rigidity of the sheath or adding metal armor. These solutions often lead to a significant increase in the weight of the optical cable and a decrease in its flexibility, making construction and installation difficult. More importantly, this kind of static protection is easily breached by continuous gnawing by organisms, and once the sheath is damaged, the protection becomes ineffective, lacking proactive and long-term defense and repair capabilities.

[0004] Sensing signals are susceptible to interference and suffer from poor long-term stability: The accuracy and stability of distributed fiber optic sensing are highly dependent on the uniformity and predictability of the stress on the fiber. In traditional stranded or central tube optical cable structures, the fiber and the buffer layer are often tightly coupled in a "surface contact" manner. Under the complex alternating mechanical stress generated by temperature cycling, wind galloping, icing, etc., such structures are prone to uneven stress transmission, leading to increased microbending loss in the fiber and nonlinear drift of the sensing signal, which seriously restricts the long-term reliability and accuracy of monitoring data.

[0005] The overall environmental durability faces challenges: high-voltage transmission corridors operate in harsh environments, constantly exposed to strong ultraviolet radiation, rain, snow, salt spray, and drastic temperature changes. Ordinary polyolefin sheathing materials are prone to photo-oxidative aging, leading to embrittlement, cracking, and loss of protection for the internal structure.

[0006] Existing solutions often focus on improving a single performance aspect, making it difficult to achieve an effective balance between multiple demanding requirements such as high temperature resistance, bite resistance, mechanical flexibility, environmental tolerance, and signal stability.

[0007] Therefore, there is an urgent need for a high-performance special sensing optical cable that can systematically solve the above problems and maintain long-term stable operation under ultra-wide temperature range, mechanical stress, biological attack and harsh climate. Summary of the Invention

[0008] To address the aforementioned technical problems, the present invention aims to provide a high-temperature resistant and anti-gnawing composite sensing optical cable. The optical cable provided by this invention simultaneously meets the stringent requirements of high-voltage transmission lines for long-term operation over an ultra-wide temperature range, triple biomimetic collaborative active anti-gnawing, high-precision sensing signal stability, and ultra-long environmental lifespan, achieving long-term reliability and accuracy for distributed monitoring in extremely complex environments.

[0009] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution: The present invention provides a high-temperature resistant and anti-biting composite sensing optical cable, which includes, from the inside out: a sensing optical fiber unit, a stress decoupling buffer layer, a composite tensile reinforcement layer, a biomimetic synergistic protection layer, and a weather-resistant outer sheath; The outer surface of the sensing fiber unit is provided with regularly distributed micro-protrusion structures, which are embedded in the stress decoupling buffer layer to form a three-dimensional discrete support interface. The biomimetic synergistic protective layer comprises an inner barrier layer, a functional release layer, and an outer constraint layer arranged sequentially from the inside out. The functional release layer is a composite material layer with internal and external functional gradients. Its inner layer is a mechanically reinforcing layer with high modulus and high thermal conductivity, and its outer layer is a chemically functional layer with repellent microcapsules as the functional body. The outer constraint layer is a tubular mesh woven from shape memory alloy wires.

[0010] Furthermore, the sensing fiber unit includes at least one optical fiber with a polyimide / nano-ceramic composite coating, the optical fiber being encapsulated in a thin-walled Invar alloy tube, the outer surface of which is provided with the micro-protrusion structure; the thin-walled Invar alloy tube is filled with thixotropic high-temperature resistant silicone grease.

[0011] Furthermore, the stress decoupling buffer layer has a double-layer co-extruded structure: the inner layer is open-cell foamed silicone rubber, and the outer layer is solid fluorosilicone rubber.

[0012] Furthermore, in the functional release layer, the high modulus and high thermal conductivity of the mechanical reinforcement layer are achieved by adding reinforcing materials, which include at least one of silicon carbide whiskers, boron nitride nanosheets, or carbon nanotubes; in the chemical functional layer, the repellent microcapsules are capsaicin-cinnamaldehyde composite microcapsules.

[0013] Further, by weight, the mechanical reinforcement layer comprises the following components: 100 parts of PEEK resin, 10-15 parts of perfluoropolyether, and 18-25 parts of silicon carbide whiskers. The chemical functional layer comprises the following components: 100 parts of PEEK resin, 8-10 parts of perfluoropolyether, 6-10 parts of repellent microcapsules, and 5-10 parts of silicon carbide whiskers.

[0014] Furthermore, the austenitic phase transformation end temperature Af of the shape memory alloy wire in the outer constraint layer is 45℃~55℃.

[0015] Furthermore, the inner barrier layer is a micro-perforated titanium alloy foil strip.

[0016] Furthermore, the composite tensile reinforcement layer is formed by spirally winding composite reinforcement yarn in opposite twisting directions. The composite reinforcement yarn is a blended yarn of poly(p-phenylenebenzodioxazole) fiber and basalt fiber.

[0017] Furthermore, the weather-resistant outer sheath is a blend of polyvinylidene fluoride and polyamide-imide, and its surface is provided with anti-slip texture.

[0018] Another aspect of the present invention provides a method for preparing a high-temperature resistant and bite-resistant composite sensing optical cable, comprising the following steps: Fabrication of sensing fiber unit: Regularly distributed micro-protrusion structures are formed on the outer surface of the sensing fiber unit; Forming a stress decoupling buffer layer: A buffer layer material is extruded onto the outside of the sensing fiber unit, so that the micro-protrusion structure is embedded therein, forming a three-dimensional discrete support interface; Constructing a composite tensile reinforcement layer: outside the stress decoupling buffer layer, composite reinforcing yarns are twisted or woven; Constructing a biomimetic collaborative protection layer: an inner barrier layer, a functional release layer, and an outer constraint layer are formed sequentially; wherein, the functional release layer is formed with an internal and external functional gradient through twin-screw co-extrusion and electrostatic spraying processes; Extruded weather-resistant outer sheath; The sensing performance of the finished optical cable is calibrated.

[0019] The beneficial effects of this invention are as follows: The micro-protrusion structure of the sensing fiber unit in this invention incorporates a stress decoupling buffer layer, forming a "three-dimensional discrete support interface" that alters the mechanical transmission path. External mechanical loads (lateral pressure, bending) are concentrated and transmitted to the discrete protrusion apexes, where they are significantly absorbed, dissipated, and homogenized in the buffer material region between the protrusions. This structure effectively blocks the direct transmission of non-uniform, localized stress to the sensing fiber, transforming the lateral compressive force and localized micro-bending that easily cause signal drift into a homogenized load with minimal impact on the fiber, thus solving the long-term signal drift problem caused by stress coupling in traditional structures.

[0020] This invention fundamentally isolates the interference of external non-uniform mechanical stress on the sensing fiber by using a unique "three-dimensional discrete support interface" (composed of a micro-protrusion structure on the surface of the sensing fiber unit and a stress decoupling buffer layer) and a precise all-metal (thin-walled Invar alloy tube) encapsulation, thereby achieving long-term high stability and high accuracy of distributed temperature and strain sensing.

[0021] The biomimetic synergistic protective layer in this invention constructs a three-tiered sequential defense system from the outside to the inside, consisting of an outer shape memory alloy constraint grid, a gradient function release layer, and an inner barrier layer, which works in concert.

[0022] When an optical cable is attacked by external bites, the attack first acts on the outermost weather-resistant outer sheath. If the bite continues and penetrates the outer sheath, a step-by-step defense sequence of the biomimetic collaborative protection layer is initiated: the outermost shape memory alloy constraint mesh first provides mechanical resistance with its high-strength braided structure, and undergoes phase transformation hardening triggered by the frictional heat of the bite or high ambient temperature (such as summer sunlight), actively tightening and strengthening local rigidity, forming the first dynamic line of defense. If the attack further penetrates into the inner functional release layer, the repellent microcapsules in the outer chemical functional layer of this layer immediately rupture and release to repel the rodent. The internal mechanical reinforcement layer of this layer provides continuous skeletal support for the entire functional release layer, resisting crushing deformation. Finally, as the innermost high-hardness physical barrier of this protection system, the micro-perforated titanium alloy foil strip of the inner barrier layer constitutes the ultimate defense, effectively resisting and dispersing the remaining penetration stress, ensuring the safety of the internal sensing fiber unit. At the same time, thanks to the "three-dimensional discrete support interface" formed between the sensing fiber unit and the buffer layer, the internal fiber maintains a stress decoupling state, ensuring the long-term stability of the distributed sensing signal throughout the entire external mechanical intrusion process. This design achieves a sequential response and synergistic defense from the outside in, from "intelligent constraint" to "chemical repair" and then to "ultimate physical barrier".

[0023] This invention enables the optical cable to operate stably for a long time within an ultra-wide temperature range (e.g., -65℃ to +200℃) through the all-metal encapsulation of the sensing fiber unit, the use of high-temperature resistant materials in each functional layer, and the matching structural design, effectively coping with the extreme temperature difference environment of high-voltage power transmission corridors.

[0024] The mechanically reinforcing layer in this invention, with its high modulus and high thermal conductivity, can rapidly dissipate internal heat or homogenize external thermal shocks, preventing heat buildup that could damage the optical fiber, and synergistically triggers the shape memory alloy of the outer constraint layer. The entire optical cable can withstand short-circuit current thermal shocks of 300°C for short periods without structural failure.

[0025] The composite tensile reinforcement layer in this invention not only imparts ultra-high tensile strength to the optical cable, but also significantly reduces its weight and maintains excellent flexibility, solving the problem of traditional armored sensing optical cables being bulky and rigid, and facilitating construction and laying.

[0026] The weather-resistant outer sheath in this invention gives the optical cable excellent resistance to ultraviolet rays, high and low temperatures, chemical corrosion, and creep, enabling it to serve stably for a long time in harsh outdoor environments such as high-voltage power transmission corridors. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the high-temperature resistant and bite-resistant composite sensing optical cable of the present invention.

[0028] Figure 2 This is a schematic diagram of the structure of a single optical fiber in the sensing optical fiber unit of the present invention.

[0029] Figure 3 This is a schematic diagram of the structure of the biomimetic collaborative protective layer in this invention.

[0030] In the figure, 1: sensing fiber unit, 11: optical fiber, 12: thin-walled Invar alloy tube, 13: thixotropic high-temperature resistant silicone grease; 2: stress decoupling buffer layer; 3: composite tensile reinforcement layer; 4: biomimetic synergistic protection layer, 41: inner barrier layer, 42: function release layer, 43: outer constraint layer; 5: weather-resistant outer sheath. Detailed Implementation

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. 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.

[0032] like Figure 1As shown, this invention provides a high-temperature resistant and bite-resistant composite sensing optical cable, which systematically solves the comprehensive problems of signal stability, active protection, mechanical performance, and environmental durability in high-voltage transmission line monitoring through an innovative layered composite structure. The optical cable, exemplarily comprising from the inside out,: a sensing fiber unit 1, a stress decoupling buffer layer 2, a composite tensile reinforcement layer 3, a biomimetic synergistic protection layer 4, and a weather-resistant outer sheath 5.

[0033] The sensing fiber unit 1 is the core of the optical cable's monitoring function. Exemplarily, this unit includes at least one optical fiber 11 with a high-temperature resistant coating. The coating is a composite coating of polyimide and nano-ceramics (such as nano-zirconia, with an example particle size of 20-40 nm), with an example coating thickness of 35-45 μm. Figure 2 As shown, to provide better stress isolation and protection, the optical fiber 11 can be encapsulated in a thin-walled Invar alloy tube 12 and filled with thixotropic high-temperature resistant silicone grease 13. The silicone grease may contain thermally conductive fillers such as boron nitride and alumina to improve its thermal conductivity and thermal management performance. The filling degree is required to be ≥97% for example.

[0034] The outer surface of the sensing fiber unit 1 (particularly the Invar alloy tube 12 outside it) is provided with regularly distributed micro-protrusion structures. These structures can be integrally formed, for example, by processes such as laser etching or precision rolling, and can appear as a dot matrix or spiral ridges. In subsequent processes, when the stress decoupling buffer layer material is applied to the outside of the sensing fiber unit 1, these micro-protrusion structures will embed into the buffer layer material, thereby collectively forming a three-dimensional discrete support interface.

[0035] The material and structure of the stress decoupling buffer layer 2 can be further optimized. For example, a double-layer co-extruded structure can be adopted: the inner layer is open-cell foamed silicone rubber with an example open-cell ratio of 35%-45% and an example Shore A hardness of 18-22; the outer layer is solid fluorosilicone rubber with an example Shore A hardness of 40-50.

[0036] The stress decoupling buffer layer 2 is extruded and coated on the outside of the sensing fiber unit 1. Its internal shape is adapted to the outer contour of the sensing fiber unit 1 array and forms a three-dimensional discrete contact with the micro-protrusion structure on the surface of the thin-walled Invar alloy tube 12. The buffer layer material fills part of the gap between each tube.

[0037] Outside the stress decoupling buffer layer 2, a composite tensile reinforcement layer 3 is provided. Exemplarily, this layer is formed by spirally winding a blend of poly(p-phenylenebenzodioxazole) fibers and basalt fibers in opposite twisting directions. The mass ratio of the two fibers in the blended yarn is, for example, 4:1 to 5:1. During twisting, two opposite directions are used, exemplarily S-direction and Z-direction, where the S-direction twisting pitch is, for example, 200-220 mm, and the Z-direction twisting pitch is, for example, 180-200 mm. This bidirectional balanced twisting design effectively suppresses torsion while imparting ultra-high breaking strength to the optical cable.

[0038] like Figure 3 As shown, the biomimetic collaborative protection layer 4 exemplarily includes an inner barrier layer 41, a function release layer 42, and an outer constraint layer 43 arranged sequentially from the inside to the outside. When the optical cable is subjected to external damage, each layer responds sequentially from the outside to the inside, jointly constructing a triple defense system of "intelligent constraint - chemical repair / mechanical support - physical barrier".

[0039] The outer constraint layer 43 is exemplarily a tubular mesh woven from shape memory alloy wires (such as nickel-titanium alloy wires). The austenitic phase transformation end temperature (Af point) of the shape memory alloy wires is exemplarily set between 45°C and 55°C, and the braiding angle is 54.7°±2°. This layer not only provides high-strength mechanical constraint itself, but also undergoes phase transformation hardening triggered by biting frictional heat or high ambient temperatures (such as line overload or summer sunlight), actively tightening and significantly improving local rigidity.

[0040] The functional release layer 42 is located inside the outer constraint layer 43 and is a composite material layer with internal and external functional gradients. It is integrally formed by twin-screw co-extrusion combined with electrostatic spraying and other processes, exemplarily. During preparation, the melt temperature can be exemplarily controlled at 380℃~400℃, the electrostatic spraying voltage can be exemplarily controlled at 55~65kV, and water quenching can be performed immediately after spraying at a cooling rate of >100℃ / s.

[0041] The outer layer (chemical functional layer) of the functional release layer 42 focuses on an immediate and active response after structural damage. This layer can be composed of repellent microcapsules dispersed within a polymer matrix. Exemplarily, the repellent microcapsules may be capsaicin-cinnamaldehyde composite microcapsules. The microcapsules have an average particle size of 10-20 μm and a wall material of gelatin-gum arabic composite cohesive layer. By weight, the chemical functional layer exemplarily comprises: 100 parts PEEK resin, 8-10 parts perfluoropolyether, 6-10 parts repellent microcapsules, and 5-10 parts silicon carbide whiskers. When the attack breaches the outer restraint layer 43, causing damage to this outer layer, the repellent microcapsules immediately rupture to release the repellent and repel the organism.

[0042] The inner layer (mechanical reinforcement layer) of the functional release layer 42 focuses on providing continuous skeletal support and thermal management for the entire functional release layer 42. This layer can be achieved by adding a high-modulus, high-thermal-conductivity reinforcing material to a high-performance polymer matrix (such as polyetheretherketone, PEEK), wherein the reinforcing material exemplary comprises at least one of silicon carbide whiskers, boron nitride nanosheets, or carbon nanotubes. The mechanical reinforcement layer, by weight, exemplary comprises: 100 parts PEEK resin, 10-15 parts perfluoropolyether, and 18-25 parts silicon carbide whiskers. This layer provides mechanical support against crushing deformation while responding to the chemical functional layer, and conducts heat inward or outward.

[0043] Inner Barrier Layer 41: As the innermost and ultimate physical barrier of the biomimetic protection system, it is exemplarily made of microperforated titanium alloy (such as TC4) foil strip with an example thickness of 0.08-0.12 mm. The pore size of the microperforations is 80-120 μm, and the pore density is 250-350 pores / cm². 2 After the penetration function release layer 42 is damaged, this high-hardness layer will provide a final resistance and dispersion to the remaining penetration stress, protecting the internal sensing unit.

[0044] The weather-resistant outer sheath 5 constitutes the first overall barrier against environmental factors for the optical cable. Exemplarily, its material is a blend of polyvinylidene fluoride (PVDF) and polyamide-imide, wherein the mass percentage of PVDF is, for example, 60%–70%, and a UV-shielding agent composed of nano-titanium dioxide and carbon black may be added, for example, at a level of 2%–5%. In addition, an appropriate amount of weather-resistant color masterbatch (e.g., to give it a warning orange-red color) may be added for easy identification during outdoor inspections. The sheath thickness is, for example, 1.8 ± 0.2 mm, and its surface may be provided with anti-slip textures, for example, at a depth of 0.3–0.5 mm.

[0045] The above-mentioned method for manufacturing optical cables may, by way of example, include the following steps: S1. Fabrication of sensing fiber unit 1: An optical fiber 11 with a polyimide / nano-ceramic coating is inserted into a thin-walled Invar alloy tube 12 under a vacuum degree ≤10. -2 Thixotropic high-temperature resistant silicone grease 13, preheated to 85±5℃, is injected under Pa conditions and cooled to set. Subsequently, a micro-protrusion structure is formed on the outer surface of the thin-walled Invar alloy tube 12. S2. Forming stress decoupling buffer layer 2: Outside the sensing fiber unit 1, a foamed silicone rubber inner layer and a fluorosilicone rubber outer layer are extruded sequentially using a dual-head co-extrusion die, embedding the micro-protrusion structure therein to form a three-dimensional discrete support interface. Subsequently, pre-crosslinking can be performed via electron irradiation, with an example irradiation dose of 14-16 kGy. S3. Constructing a composite tensile reinforcement layer 3: Outside the stress decoupling buffer layer 2, the PBO and basalt fiber blended yarn is bidirectionally balanced twisted with the example S-direction and Z-direction pitches; S4. Constructing the biomimetic collaborative protective layer 4: Perform the following operations in sequence: a. A longitudinally wrapped micro-perforated titanium alloy foil strip is used as an inner barrier layer 41.

[0046] b. Constructing the functional release layer 42: A one-time molding process combining twin-screw co-extrusion and electrostatic melt spraying is employed. The separately plasticized inner layer (mechanical reinforcement layer) and outer layer (chemical functional layer) materials are combined through a specially designed gradient distribution die to form a composite melt with continuously transitioning components. This melt is then sprayed onto the surface of the optical cable under an electrostatic voltage of 55–65 kV and water-quenched at a rate >100℃ / s to achieve a gradient composite layer that combines mechanical support, thermal conductivity, and chemical repellency. c. At temperatures below the Af point, shape memory alloy wires are woven into a tubular mesh as an outer constraint layer 43.

[0047] S5. Extruded weather-resistant outer sheath 5: The PVDF / PAI blend is extruded and coated at 290℃~310℃, and after water cooling, it is placed in a heat treatment furnace at 120±5℃ for 2 hours. For example, it can be carried out under nitrogen protection to eliminate internal stress. S6. Performance Calibration: Perform full-process temperature and strain calibration on the finished optical cable and establish a mapping database between sensor signals and actual physical quantities.

[0048] The present invention will be further described below through specific embodiments.

[0049] Example 1: Composite sensing optical cable for 500kV lines This embodiment 1 provides a high-temperature resistant and bite-resistant composite sensing optical cable for distributed temperature and strain monitoring of 500kV high-voltage transmission lines. Its specific structure and process parameters are as follows: Sensing fiber unit 1: comprises four polyimide / nanozirconia composite coated optical fibers 11, two of which are single-mode fibers and two are multimode fibers to provide redundancy and support multi-parameter sensing. The optical fibers 11 are encapsulated within a thin-walled Invar alloy tube 12 with an inner diameter (ID) of 1.5 mm, and the tube is vacuum-filled with Dow Corning SE-9187L thixotropic high-temperature resistant silicone grease 13, with a fill degree ≥97%.

[0050] Stress decoupling buffer layer 2: It is a double-layer co-extruded structure, directly covering the outside of the sensing unit. The inner layer is a foamed silicone rubber with an open porosity of 40% and a Shore A hardness of 20, with a thickness of 0.8mm; the outer layer is a solid fluorosilicone rubber with a Shore A hardness of 45, with a thickness of 0.5mm.

[0051] Composite tensile reinforcement layer 3: Composed of 24 reinforcing yarns spirally wound in opposite directions. Each yarn is a blend of PBO fiber (Zylon® HM type) and basalt fiber at a mass ratio of 4.5:1. The S-direction twist pitch is 210mm, and the Z-direction twist pitch is 190mm, forming a bidirectional balanced structure.

[0052] Bionic Synergistic Protective Layer 4: Inner barrier layer 41: Made of 0.10mm thick TC4 titanium alloy foil strip, formed by laser drilling to create pores with a diameter of 100μm and a pore density of 300 pores / cm. 2 The microporous structure is longitudinally wrapped with a coverage of 78%.

[0053] Functional release layer 42: This is a composite material layer with internal and external functional gradients, consisting of an inner mechanical reinforcement layer and an outer chemical functional layer. Its specific composition by weight is as follows: Inner layer (mechanical reinforcement layer): This layer focuses on providing high modulus support and thermal conductivity. Its composition is: 100 parts PEEK (Victrex® 450G), 11 parts perfluoropolyether (Solvay Fluorolink® E10H), and 18 parts silicon carbide whiskers (diameter 0.2-1.0μm, aspect ratio >20).

[0054] Outer layer (chemical functional layer): This layer focuses on active chemical protection and is composed of: 100 parts of PEEK (Victrex® 450G), 10 parts of perfluoropolyether (Solvay Fluorolink® E10H), 6 parts of capsaicin-cinnamaldehyde composite microcapsules, and 5 parts of silicon carbide whiskers (diameter 0.2-1.0μm, aspect ratio >20).

[0055] Outer constraint layer 43: made of nickel-titanium shape memory alloy wire with a diameter of 0.15 mm and an austenitic phase transformation point (Af) of 50 °C, woven into a tubular mesh (coverage ≥90%) at a braiding angle of 54.7° and covering the outside of the functional release layer 42.

[0056] Weather-resistant outer sheath 5: The material is a blend of polyvinylidene fluoride (PVDF, Solvay Solef® 6010) and polyamide-imide (PAI, Solvay Torlon® 4203) (mass ratio PVDF:PAI=65:35), with the addition of 3.5% nano-titanium dioxide (P25) and carbon black as a UV shielding agent. The sheath is 1.8mm thick, and the surface is embossed with a 0.4mm deep spiral anti-slip texture.

[0057] The preparation process is as follows: S1. Fabrication of sensing fiber unit 1: An optical fiber 11 with a polyimide / nano-ceramic coating is inserted into a thin-walled Invar alloy tube 12, at a temperature ≤10 -2Under vacuum, SE-9187L silicone grease preheated to 85℃ is injected, followed by cooling and shaping. S2. Stress decoupling buffer layer 2 co-extrusion and cross-linking: The inner layer of foamed silicone rubber and the outer layer of fluorosilicone rubber are co-extruded using a dual-head die, followed by electron irradiation pre-cross-linking with an irradiation dose of 15 kGy.

[0058] S3. Composite tensile reinforcement layer 3 twisting: PBO / basalt blended yarn is bidirectionally twisted at a pitch of 210mm in the S direction and 190mm in the Z direction.

[0059] S4. Construction of the biomimetic collaborative protective layer 4: a. Inner barrier layer 41: A micro-perforated titanium alloy foil strip (thickness 0.10 mm, pore size 100 μm, pore density 300 pores / cm²) 2 It is spirally wrapped around the outside of the composite tensile reinforcement layer 3 with a coverage of 78%; b. Preparation and coating of functional release layer 42: A process combining twin-screw co-extrusion and electrostatic spraying is used to form a functional release layer 42 with internal and external functional gradients; Material preparation: The mechanical reinforcement layer material and the chemical functional layer material are melt-plasticized in their respective twin-screw extruders.

[0060] Gradient co-extrusion and spraying: Two melts are combined and extruded through a specially designed gradient distribution die to form a composite melt flow with a continuous composition transition. Subsequently, this composite melt flow is electrostatically sprayed through an annular die under a high-voltage electrostatic field of 60±5kV, uniformly coating the outer surface of the inner barrier layer 41.

[0061] Rapid shaping: The coated layer is immediately subjected to water quenching with a cooling rate >100℃ / s to form a functional release layer 42 with a total thickness of 0.8mm and a continuous gradient from the inner layer (high silicon carbide whisker content) to the outer layer (high microcapsule content).

[0062] c. Braided outer constraint layer 43: After the functional release layer 42 is cured, in an environment below its austenitic phase transformation end temperature (Af point, 50℃), a 0.15mm diameter nickel-titanium shape memory alloy wire is braided into a tubular mesh at a braiding angle of 54.7° and covered outside the functional release layer 42, with a coverage rate of ≥90%.

[0063] S5. Weather-resistant outer sheath 5 Extrusion and post-treatment: The PVDF / PAI blend is extruded and coated at 300℃, then water-cooled and heat-treated in a nitrogen atmosphere at 120℃ for 2 hours.

[0064] S6. Performance Calibration: The finished optical cable is calibrated at a temperature of -65℃ to 200℃ and a strain of 0 to 2000µε throughout the entire range, and a signal mapping database is established.

[0065] Example 2: Optimized optical cable for multi-parameter monitoring Based on Example 1, this example is optimized in the following way to meet the requirements of simultaneous temperature, strain and vibration monitoring: Replace the single-mode fiber in sensing fiber unit 1 with a "bow tie" polarization-maintaining fiber with the same polyimide / nanozirconia coating.

[0066] The SE-9187L silicone grease filling the thin-walled Invar alloy tube 12 was replaced with the same type of silicone grease containing 30wt% boron nitride filler to improve axial thermal conductivity and optimize temperature sensing response consistency.

[0067] Weather-resistant color masterbatch 5 is added to the weather-resistant outer sheath to make it a warning orange-red color, which is convenient for outdoor inspection and identification.

[0068] The remaining structure, materials and process parameters are consistent with those in Example 1.

[0069] The high-temperature resistant and anti-biting composite sensing optical cable prepared in Example 1 above was subjected to systematic performance testing, and the test results are shown in Table 1.

[0070] Table 1

[0071] The above test results demonstrate that the optical cable of this invention has achieved significant breakthroughs in core performance: the sensing signal maintains ultra-high accuracy and stability under harsh working conditions (temperature standard deviation ±0.28℃, strain error ±2.5µε); it has active response and intelligent enhanced anti-biting capabilities; it can work for a long time in an ultra-wide temperature range of -65℃ to +200℃ and withstand short-term thermal shock of nearly 300℃; at the same time, while maintaining ultra-high mechanical strength (≥146kN), it achieves lightweight and excellent flexibility.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0073] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high temperature resistant, bite resistant, composite sensing optical cable, characterized by, From inside to outside, it comprises a sensing fiber unit, a stress decoupling buffer layer, a composite tensile reinforcing layer, a bionic synergistic protective layer and a weather-resistant outer sheath. The outer surface of the sensing fiber unit is provided with regularly distributed micro-protrusion structures embedded in the stress decoupling buffer layer to form a three-dimensional discrete support interface. The bionic synergistic protective layer comprises an inner barrier layer, a functional release layer and an outer constraint layer arranged in sequence from inside to outside; the functional release layer is a composite material layer with internal and external functional gradients, the inner layer is a mechanical strengthening layer with high modulus and high thermal conductivity, and the outer layer is a chemical functional layer with microcapsules of repellent as functional bodies; the outer constraint layer is a tubular grid woven by shape memory alloy wires.

2. The high temperature resistant, anti-chewing composite sensing optical cable of claim 1, wherein, The sensing fiber unit comprises at least one optical fiber with a polyimide / nano-ceramic composite coating, which is packaged in a thin-walled invar alloy tube, and the outer surface of the thin-walled invar alloy tube is provided with the micro-protrusion structure; the thin-walled invar alloy tube is filled with a thixotropic high-temperature-resistant silicone grease.

3. The high temperature resistant, anti-chewing composite sensing optical cable of claim 1, wherein, The stress decoupling buffer layer is a double-layer co-extrusion structure: the inner layer is an open-cell foamed silicone rubber, and the outer layer is a solid fluorosilicone rubber.

4. The high temperature resistant, anti-chewing composite sensing optical cable of claim 1, wherein, In the functional release layer, the high modulus and high thermal conductivity characteristics in the mechanical strengthening layer are achieved by adding reinforcing materials, which include at least one of silicon carbide whiskers, boron nitride nanosheets or carbon nanotubes; in the chemical functional layer, the repellent microcapsules are capsaicin-cinnamaldehyde composite microcapsules.

5. The high temperature resistant, anti-chewing composite sensing optical cable of claim 4, wherein, The mechanical strengthening layer comprises the following components by weight: PEEK resin 100 parts, perfluoropolyether 10-15 parts, silicon carbide whiskers 18-25 parts; The chemical functional layer comprises the following components: PEEK resin 100 parts, perfluoropolyether 8-10 parts, repellent microcapsules 6-10 parts, silicon carbide whiskers 5-10 parts.

6. The high temperature resistant, anti-chew composite sensing optical cable of claim 1, wherein, The austenite phase transformation end temperature Af point of the shape memory alloy wire in the outer constraint layer is 45-55℃.

7. The high temperature resistant, anti-chew composite sensing optical cable of claim 1, wherein, The inner barrier layer is a micro-perforated titanium alloy foil.

8. The high temperature resistant, anti-chew composite sensing optical cable of claim 1, wherein, The composite tensile reinforcing layer is spirally wound by composite reinforcing yarns in opposite twisting directions, and the composite reinforcing yarns are poly-p-phenylene benzobisoxazole fibers and basalt fiber mixed yarns.

9. The high temperature resistant, anti-chew composite sensing optical cable of claim 1, wherein, The weather-resistant outer sheath is a blend of polyvinylidene fluoride and polyamide imide, and the surface is provided with anti-slip lines.

10. A method of making a high temperature resistant, bite resistant composite sensing optical cable as claimed in any one of claims 1 to 9, characterized in that, The steps include: Preparation of a sensing fiber unit: regularly distributed micro-protrusion structures are formed on the outer surface of the sensing fiber unit; Forming a stress decoupling buffer layer: extruding a buffer layer material outside the sensing fiber unit, embedding the micro-protrusion structures therein to form a three-dimensional discrete support interface; Building a composite tensile reinforcing layer: twisting or weaving composite reinforcing yarns outside the stress decoupling buffer layer; Building a bionic synergistic protective layer: sequentially forming an inner barrier layer, a functional release layer and an outer constraint layer; wherein the functional release layer forms a structure with internal and external functional gradients through double-screw co-extrusion and electrostatic spraying process; Extruding a weather-resistant outer sheath; Calibrating the sensing performance of the finished optical cable.

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