A multi-layer shielded fiber optic composite aerospace cable and method of making the same

Abstract

The application relates to the technical field of cables, solves the problems of insufficient vibration fatigue resistance and high-energy radiation performance of existing aerospace cables, and specifically discloses a multi-layer shielded optical fiber composite aerospace cable and a preparation method thereof, which comprises, from inside to outside, an insulation layer, an inner shielding layer, a buffer bonding layer and an outer shielding layer; the insulation layer is internally provided with a conductor core and an optical fiber bundle, and the insulation layer comprises, from inside to outside, a bonding transition layer, a core insulation layer and an anti-radiation protection layer; the inner shielding layer comprises a nano-silver conductive film and a silicone rubber elastic layer, and the nano-silver conductive film is arranged on the inner side of the silicone rubber elastic layer; the outer shielding layer is provided with a nickel-copper alloy wire mesh; and the buffer bonding layer is provided with a modified polyimide glue layer. The application is used for an optical fiber composite aerospace cable and a preparation process thereof, the inner shielding layer, the buffer bonding layer and related preparation parameter control are adopted, the cable shielding, buffering and interlayer bonding performance are guaranteed, and the application requirements of aerospace are met.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to a multi-layer shielded optical fiber composite aerospace cable and its manufacturing method. Background Technology

[0002] In the aerospace field, cables, as critical "electrical lifelines," must withstand multiple stringent tests, including temperature variations, severe vibrations, high-energy radiation, and vacuum venting. Current conventional aerospace cables suffer from the following drawbacks: Firstly, it is difficult to simultaneously achieve both vibration and radiation resistance; conventional shielding layers have limitations at around 10... 6 -10 9 After several vibration cycles, fatigue fracture is likely to occur, leading to failure of electromagnetic interference protection; secondly, the separate design of power transmission and high-speed data transmission requires separate laying of power cables and communication optical cables, which occupies a large amount of cabin space, and the increased number of joints leads to an increase in the number of failure points.

[0003] To address these issues, existing cable technologies attempt to improve flexibility using multi-strand stranded conductors and enhance protection with metallic shielding layers. However, further improvements in protection require multi-layer shielding technology. Nevertheless, multi-layer shielded cables generally suffer from bottlenecks such as poor interlayer bonding and complex manufacturing processes. Therefore, there is an urgent need to develop a high-efficiency transmission cable integrating multiple shielding functions to meet the demands of specialized applications in aerospace. Summary of the Invention

[0004] To address the problems of insufficient vibration fatigue resistance and high-energy radiation performance of existing aerospace cables, this invention provides a multi-layer shielded optical fiber composite aerospace cable and its preparation method.

[0005] The technical solution adopted in this invention is:

[0006] A multi-layer shielded fiber optic composite aerospace cable includes, from the inside out, an insulation layer, an inner shielding layer, a buffer bonding layer, and an outer shielding layer.

[0007] The insulating layer contains a conductor core and an optical fiber bundle, and includes an adhesive transition layer, a core insulating layer, and a radiation protection layer from the inside out.

[0008] The inner shielding layer includes a nano-silver conductive film and a silicone rubber elastic layer. The nano-silver conductive film is disposed on the inner side of the silicone rubber elastic layer. The inner shielding layer is used to shield electromagnetic signals and buffer vibration.

[0009] The outer shielding layer is provided with a nickel-copper alloy wire mesh, which works in conjunction with the inner shielding layer to provide an electromagnetic barrier and chemical corrosion protection.

[0010] The buffer adhesive layer is provided with a modified polyimide adhesive layer, which is modified by introducing flexible groups and is used to bond the inner shielding layer and the outer shielding layer.

[0011] Furthermore, the bonding transition layer is composed of modified polyimide resin, and the bonding transition layer is provided with a recessed groove structure for constraining the internal conductor core and the optical fiber bundle.

[0012] The core insulation layer is composed of perfluorinated polyether modified polytetrafluoroethylene composite material, and the inner surface of the core insulation layer is provided with a spiral groove texture.

[0013] The radiation protection layer is composed of phenyl silicone rubber modified polyether ether ketone resin, and annular ribs are integrally formed on the outer surface along the circumferential direction, with the annular ribs being distributed at equal intervals.

[0014] Furthermore, the conductor core is hollow and is formed by layering multiple strands of ultra-fine aluminum-magnesium alloy wires. The optical fiber bundle includes polyimide-coated single-mode optical fiber. The optical fiber bundle is evenly distributed along the circumference of the hollow conductor core and is attached to the conductor core. The arc shape of the contact surface between the optical fiber bundle and the conductor core is consistent with the outer surface of the conductor core.

[0015] Furthermore, the total thickness of the inner shielding layer is 0.08mm-0.12mm, wherein the thickness of the nano-silver film is 0.05mm-0.07mm, the thickness of the silicone rubber layer is 0.03-0.05mm, the nano-silver particles have a particle size of 20nm-50nm, and the radiation resistance dose is ≥10. 8 Rad.

[0016] Furthermore, the thickness of the buffer adhesive layer is 0.03mm-0.05mm, the adhesive strength is ≥1.5N / mm, the elongation at break is ≥20%, and the temperature resistance range is -200℃ to +260℃.

[0017] Furthermore, the outer shielding layer has a nickel-copper alloy wire diameter of 0.1mm-0.15mm, a braiding angle of 30°-45°, a braiding density of ≥95%, a shielding attenuation of ≥85dB, and a tensile strength of ≥500MPa.

[0018] A method for preparing the above-mentioned multi-layer shielded optical fiber composite aerospace cable includes the following steps:

[0019] S100, Prepare hollow conductor core and complete the bonding and layout of optical fiber bundle;

[0020] S200: An insulating layer is formed by sequentially forming a bonding transition layer, a core insulation layer, and a radiation protection layer on the outside of the conductor core and the optical fiber bundle.

[0021] S300. An inner shielding layer is prepared on the outside of the insulating layer and a buffer adhesive layer is coated thereon.

[0022] S400, the outer shielding layer is woven and formed on the outside of the buffer adhesive layer and then post-processed.

[0023] Furthermore, S100 also includes:

[0024] S101. Select multiple strands of ultra-fine aluminum-magnesium alloy wire and use a layered stranding process to form a hollow conductor core. During the stranding process, control the stranding pitch to be 8-12 times the outer diameter of the conductor core.

[0025] S102. Select polyimide-coated single-mode optical fiber, cut and arrange it to form an optical fiber bundle, so that the arc shape of the bonding surface between the optical fiber bundle and the conductor core is consistent with the outer surface of the conductor core.

[0026] S103. The optical fiber bundle is evenly distributed and fixed along the circumference of the hollow conductor core. During the fixing process, a temporary adhesive is used for positioning. After the fixing is completed, the temporary adhesive is removed by pyrolysis.

[0027] Furthermore, S200 also includes:

[0028] S201. An extrusion molding process is used to prepare a bonding transition layer on the outside of the conductor core and the optical fiber bundle. During the molding process, the system integrates an online thickness monitoring sensor and an extrusion speed closed-loop control system to collect the thickness data of the bonding transition layer in real time and compare it with a preset thickness threshold. When the monitored thickness deviates from the threshold, the system automatically adjusts the extruder speed. The adjustment range is linearly positively correlated with the thickness deviation. Simultaneously, a recessed groove structure is pressed. The size of the recessed groove structure matches the cross-sectional size of the conductor core and the optical fiber bundle to control the thickness deviation of the bonding transition layer.

[0029] S202. A core insulating layer is prepared on the outside of the bonding transition layer using a melt coating process. The temperature of the coating melt is monitored in real time by an infrared temperature sensor to control the temperature fluctuation of the coating melt. At the same time, the depth and pitch of the spiral groove texture on the inner side of the core insulating layer are monitored by a laser contour sensor. When the texture parameters deviate from the preset value, the spiral pattern parameters of the coating mold and the coating travel speed are automatically adjusted to control the pitch of the spiral groove texture on the inner side of the core insulating layer.

[0030] S203. An anti-radiation protective layer is prepared on the outside of the core insulation layer using injection molding. The system integrates a vision inspection system to identify the forming size and spacing of the annular ribs in real time. Combined with a pressure sensor to collect injection pressure data, when the size and spacing of the annular ribs deviate from the preset value, the system automatically adjusts the injection pressure of the injection molding machine and the mold opening and closing speed. The annular ribs are integrally formed during the molding process, and the forming size and spacing of the annular ribs are controlled.

[0031] Furthermore, S300 also includes:

[0032] S301. A nano-silver conductive film is deposited on the outside of the insulating layer using magnetron sputtering. The system integrates a plasma density monitoring sensor and a sputtering power closed-loop control system to monitor the plasma density in the sputtering area in real time. When the density deviates from the preset range, the sputtering power and argon flow rate are automatically adjusted to control the particle size of the nano-silver particles. The deposition thickness is monitored in real time by a quartz crystal microbalance. When the thickness reaches the preset value, the system automatically stops sputtering to control the deposition thickness of the nano-silver conductive film.

[0033] S302. A silicone rubber elastic layer is prepared on the outside of the nano-silver conductive film using a coating and curing process. The curing environment temperature is monitored in real time by a temperature sensor, and the temperature fluctuation of the curing environment is controlled to control the curing temperature, time, and thickness of the silicone rubber elastic layer.

[0034] S303. A modified polyimide adhesive layer is coated on the outside of the silicone rubber elastic layer using a spraying process. The system integrates a coating thickness sensor and a spraying pressure closed-loop control system, and collects coating thickness data in real time. When the thickness deviates from the preset range, the spraying pressure and the speed of the spray gun are automatically adjusted to control the coating thickness of the modified polyimide adhesive layer. The humidity of the coating environment is monitored by a humidity sensor. When the humidity deviates from the preset value, the system automatically starts the dehumidification device and adjusts the low-temperature curing time to control the humidity of the coating environment and the low-temperature curing time. After coating, a low-temperature curing treatment is performed to control the temperature and time of low-temperature curing.

[0035] The beneficial effects of this invention are:

[0036] This invention integrates the conductor core and optical fiber bundle within the insulation layer of the cable, achieving integrated power transmission and high-speed data transmission. This eliminates the need for separate cabling of two types, effectively reducing space occupation and minimizing joint failure points. The radiation protection layer within the insulation directly resists high-energy radiation, forming a comprehensive protection system in conjunction with the dual electromagnetic shielding design of the inner and outer shielding layers. The silicone rubber elastic layer of the inner shielding layer provides elastic buffering capabilities, absorbing vibration energy in a vibrating environment and preventing fatigue fracture of the shielding structure due to vibration. The nano-silver conductive film enhances the electromagnetic shielding effect, while the outer nickel-copper alloy wire braid further strengthens the electromagnetic barrier and provides chemical corrosion protection. The modified polyimide adhesive layer of the buffer bonding layer improves interlayer adhesion by introducing flexible groups, overcoming the bottleneck of poor interlayer bonding in multi-layer shielding structures and ensuring stable and coordinated operation of each layer. Through the above structures and their synergistic effects, this invention effectively improves the cable's resistance to vibration fatigue and high-energy radiation, achieving multi-functional integration of electromagnetic shielding, chemical corrosion protection, and integrated transmission. It simplifies the manufacturing process of multi-layer shielded cables and meets the usage requirements of aerospace applications. Attached Figure Description

[0037] Figure 1This is a schematic diagram of the cable cross-section structure of the present invention;

[0038] Figure 2 This is a schematic diagram of the cable cross-sectional structure of the present invention;

[0039] Figure 3 This is a flowchart of the cable manufacturing method of the present invention.

[0040] Figure label:

[0041] 1-Insulation layer, 2-Inner shielding layer, 3-Buffer bonding layer, 4-Outer shielding layer, 5-Outer jacket layer, 6-Conductor core, 7-Fiber optic bundle, 8-Groove, 9-Annular rib. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0043] Example 1: The multi-layer shielded fiber optic composite aerospace cable of this example, such as... Figures 1-2 As shown, the insulation layer 1 consists of a bonding transition layer, a core insulation layer, and a radiation protection layer from the inside out. The bonding transition layer is made of modified polyimide resin, the core insulation layer is made of perfluorinated polyether modified polytetrafluoroethylene composite material, and the radiation protection layer is made of phenyl silicone rubber modified polyether ether ketone resin. The inner shielding layer 2 is composed of a nano-silver conductive film and a silicone rubber elastic layer. The outer shielding layer 4 is a nickel-copper alloy wire braided mesh, and the buffer bonding layer 3 is a modified polyimide adhesive layer with introduced flexible groups. The conductor core 6 is made of multiple strands of ultra-fine aluminum-magnesium alloy wires layered and twisted into a hollow shape. The fiber bundle 7 is a polyimide-coated single-mode fiber and is uniformly attached and laid along the circumference of the conductor core 6. The parameters for each layer can be selected as follows: the inner shielding layer 2 has a total thickness of 0.10 mm, including a nano-silver film thickness of 0.06 mm, a silicone rubber layer thickness of 0.04 mm, and nano-silver particles with a diameter of 35 nm; the buffer bonding layer 3 has a thickness of 0.04 mm; the outer shielding layer 4 has a nickel-copper alloy wire diameter of 0.12 mm, a braiding angle of 38°, and a braiding density of 97%. Based on this embodiment, the modified polyimide resin molecular chain contains strongly polar groups, which can form hydrogen bonds with the conductor core 6 and the surface of the optical fiber bundle 7. The recessed groove structure 8 further enhances the constraint stability; the perfluorinated polyether modified polytetrafluoroethylene, introduced through perfluorinated polyether segments, reduces intermolecular forces and improves the material's flexibility and resistance to high and low temperatures; in the phenyl silicone rubber modified polyether ether ketone resin, the phenyl group can capture free radicals generated by radiation, and the silicone rubber segments enhance the material's toughness. During operation, insulation layer 1 provides insulation protection between conductor core 6 and optical fiber bundle 7; radiation protection layer resists high-energy radiation; the nano-silver conductive film of inner shielding layer 2 forms the first electromagnetic shielding barrier; silicone rubber elastic layer absorbs vibration energy; outer shielding layer 4 works synergistically with inner layer to strengthen electromagnetic shielding and resist chemical corrosion; and buffer adhesive layer 3 ensures stable adhesion between shielding layers. This cable can withstand 10... 8It operates stably with radiation doses above rad and within a temperature range of -200℃ to +260℃, exhibiting an electromagnetic shielding attenuation of 88dB and a vibration cycle life of 10. 9 There was no subsequent shielding layer breakage, achieving integrated power and high-speed data transmission and significantly reducing the cabin space occupancy rate.

[0044] Example 2: This example focuses on improving radiation resistance. The cable structure is the same as in Example 1. The radiation protection layer uses phenyl silicone rubber modified polyetheretherketone resin, and the inner shielding layer 2 uses 50nm nano-silicone particles. The parameters of each layer can be adjusted as follows: the total thickness of the inner shielding layer 2 is 0.12mm, of which the nano-silicone film thickness is 0.07mm and the silicone rubber layer thickness is 0.05mm; the spacing of the annular ribs 9 on the outer surface of the radiation protection layer is twice the outer diameter of the radiation protection layer. Based on the cable of this example, when the nano-silicone particle size is increased to 50nm, a denser conductive network is formed between the particles, improving electromagnetic shielding performance. At the same time, the larger particle size makes it more difficult for lattice distortion to occur in the radiation environment. Combined with the free radical capture effect of phenyl silicone rubber modified polyetheretherketone resin, the radiation resistance is doubly improved; the reduced spacing of the annular ribs 9 can increase the structural stability of the radiation protection layer and reduce material shrinkage deformation caused by radiation. During operation, the dense nano-silver conductive film and the radiation-resistant protective layer work synergistically to effectively block high-energy radiation from damaging the internal conductor core 6 and fiber bundle 7. The annular ribs 9 disperse vibration stress, further improving the resistance to vibration fatigue. The radiation dose resistance of this invention is increased to 1.2 × 10⁻⁶. 8 Rad, in 10 9 After one vibration cycle, the shielding attenuation remains above 86dB, making it suitable for strong radiation and strong vibration environments such as deep space exploration. The structural stability is 20% higher than that of Example 1.

[0045] Example 3: This example focuses on lightweight design. The conductor core 6 is made of thinner multi-strand ultrafine aluminum-magnesium alloy wires layered and twisted, and the fiber bundle 7 is made of thin-diameter polyimide-coated single-mode fiber. The relevant parameters of the cable in this example can be selected and implemented as follows: the total thickness of the inner shielding layer 2 is 0.08mm, of which the thickness of the nano-silver film is 0.05mm and the thickness of the silicone rubber layer is 0.03mm; the thickness of the buffer bonding layer 3 is 0.03mm; the diameter of the nickel-copper alloy wire in the outer shielding layer 4 is 0.10mm, the braiding angle is 45°, and the braiding density is 95%. Based on the cable of this example, the aluminum-magnesium alloy itself has low density characteristics, and the hollow conductor core 6 formed by the stranding of thin-diameter alloy wires significantly reduces the weight while ensuring conductivity; the thinner inner shielding layer 2 and buffer bonding layer 3 are optimized through material formulation to ensure shielding performance and bonding strength while reducing thickness; although the nano-silver conductive film is thin, it can still achieve effective electromagnetic shielding due to its high conductivity; the modified polyimide adhesive layer is introduced with flexible groups, which maintain good bonding strength and elongation at break even in the thin coating state. During operation, the lightweight structure reduces the overall weight of the cable, facilitating lightweight assembly of aerospace equipment. The various structural layers work together to achieve basic electromagnetic shielding, radiation resistance, and vibration resistance. The cable of this invention has a 15% lower weight per unit length compared to Example 1, while maintaining a bonding strength of 1.6 N / mm, an elongation at break of 22%, and a shielding attenuation of 85 dB, meeting the lightweight requirements of conventional aerospace applications while reducing assembly difficulty and equipment energy consumption.

[0046] Example 4: This example focuses on high bonding strength and chemical resistance. The buffer bonding layer 3 uses a modified polyimide adhesive layer with a high content of flexible groups, and the braiding density of the nickel-copper alloy wire in the outer shielding layer 4 is increased to 98%. The relevant cable parameters in this example can be set as follows: the thickness of the buffer bonding layer 3 is 0.05 mm, and the bonding strength is ≥1.8 N / mm; the diameter of the nickel-copper alloy wire in the outer shielding layer 4 is 0.15 mm, and the braiding angle is 30°; the spacing of the annular ribs 9 in the radiation protection layer is 3 times the outer diameter of the radiation protection layer. Based on the cable of this example, the high content of flexible groups in the buffer bonding layer 3 can increase the mobility of the molecular chains, improve the interfacial bonding force between the adhesive layer and the inner shielding layer 2 and the outer shielding layer 4, and reduce the risk of interlayer delamination; the increased diameter and braiding density of the nickel-copper alloy wire form a denser protective network, which resists chemical corrosion while enhancing structural strength; the increased spacing of the annular ribs 9 can improve the flexibility of the radiation protection layer and avoid cracking during bending. During operation, the high-bonding-strength buffer adhesive layer 3 ensures the integrity of the multi-layer shielding structure, the dense outer shielding layer 4 effectively blocks chemically corrosive media, and the radiation-resistant protective layer adapts to the bending and assembly requirements of cables. The buffer adhesive layer 3 of this invention has a bonding strength of 1.9 N / mm and an elongation at break of 25%, allowing it to operate for extended periods in environments with strong chemical corrosion. The outer shielding layer 4 has a tensile strength of 520 MPa and a bending radius reduced to eight times the cable's outer diameter, making it suitable for use in complex assembly spaces.

[0047] Example 5: The cable manufacturing method of the present invention is as follows Figure 3 As shown, this embodiment focuses on the molding process of insulating layer 1 in step S200. The parameter ranges are set as follows: the thickness deviation control threshold for the bonding transition layer is ±0.005mm; the melt temperature fluctuation range for the core insulating layer is ≤±5℃; the pitch of the spiral groove texture on the inner side of the core insulating layer is 3-5 times the thickness of the core insulating layer; and the size deviation thresholds for the annular ribs 9 of the radiation protection layer are ≥0.01mm, the spacing deviation thresholds are ≥0.1mm, and the spacing is 2-3 times the outer diameter of the radiation protection layer. A preferred parameter combination is: the thickness deviation control threshold for the bonding transition layer is ±0.005mm; the melt temperature fluctuation range for the core insulating layer is ≤±3℃; the spiral groove texture pitch is 4 times the thickness of the core insulating layer; the size deviation thresholds for the annular ribs 9 are ≥0.01mm, the spacing deviation thresholds are ≥0.1mm, and the spacing is 2.5 times the outer diameter of the radiation protection layer. The sensor models used are: ZTMS08 for online thickness monitoring, OS137 for infrared temperature measurement, and Halcon 13 for the vision inspection system. Working Process and Principle: In S201, an online thickness monitoring sensor collects real-time data on the thickness of the bonding transition layer and compares it with a preset threshold. When the data deviates, the extruder speed is automatically adjusted to simultaneously press the recessed groove 8 structure. In S202, an infrared temperature sensor monitors the temperature of the coated melt to ensure temperature stability, and a laser contour sensor monitors the spiral groove texture parameters. When the data deviates, the mold parameters and travel speed are adjusted. In S203, a vision inspection system identifies the size and spacing of the annular ribs 9 and adjusts the injection molding parameters based on pressure sensor data. Reasons for Optimization: The core insulation layer melt temperature fluctuation is controlled within ±3℃, which is more accurate than ±5℃, avoiding uneven material properties caused by temperature fluctuations. The spiral groove texture pitch is selected as 4 times the median value, balancing the fit between the insulation layer 1 and the inner shielding layer 2 and the amount of material used. The spacing of the annular ribs 9 is 2.5 times, balancing structural stability and flexibility. The parameter selection tends to improve the molding accuracy and structural consistency of the insulation layer 1, ensuring the stability of the insulation and radiation resistance performance of the insulation layer 1. In this invention, the thickness deviation of each sublayer of the insulation layer 1 is controlled within ±0.003mm, the insulation resistance of the core insulation layer is increased by 10%, the radiation protection layer has good structural integrity, and there are no cracks or excessive dimensional deviations.

[0048] Example 6: This example focuses on the preparation process of the inner shielding layer 2 and the buffer bonding layer 3 in step S300. The parameter range is set to 2×10¹ plasma density in the sputtering region of the nano-silver conductive film. 5 -5×10¹ 5The parameters are: cm⁻³, nano-silver particle size 20nm-50nm, deposition thickness 0.05mm-0.07mm; silicone rubber elastic layer curing environment temperature fluctuation range ≤±3℃, curing temperature 120℃-150℃, curing time 30min-60min, thickness 0.03mm-0.05mm; modified polyimide adhesive layer coating thickness 0.03mm-0.05mm, spraying pressure 0.3MPa-0.5MPa; coating environment humidity control threshold >60%, curing time extended by 5-10min when humidity exceeds the standard; low-temperature curing temperature 80℃-100℃, time 40min-80min. Optimal parameter combination: plasma density 3.5×10¹ 5 The nano-silver particles have a diameter of 35 nm and a deposition thickness of 0.06 mm. The silicone rubber elastic layer has a curing temperature fluctuation range of ≤ ±2℃, a curing temperature of 135℃, a curing time of 45 min, and a thickness of 0.04 mm. The modified polyimide adhesive layer has a coating thickness of 0.04 mm, a spraying pressure of 0.4 MPa, a humidity control threshold of > 60%, a curing extension time of 8 min, a low-temperature curing temperature of 90℃, and a curing time of 60 min. The sensor models used are: HPR-600 plasma density monitoring sensor, QCM950 quartz crystal microbalance, CS-300 coating thickness sensor, and SHT30 humidity sensor. Working Process and Principle: In S301, the plasma density monitoring sensor monitors the density of the sputtering area. If it deviates from the preset value, the sputtering power and argon flow rate are adjusted. The quartz crystal microbalance monitors the deposition thickness, and sputtering stops when the preset value is reached. In S302, the temperature sensor monitors the curing environment temperature to ensure a stable curing process. In S303, the coating thickness sensor collects coating thickness data and adjusts the spraying pressure and travel speed. The humidity sensor monitors the ambient humidity; if it exceeds the standard, the dehumidification device is activated and the curing time is extended. Reason for Optimal Selection: The plasma density is selected as an intermediate value of 3.5 × 10¹. 5 The nanometer-diameter silver nanoparticles (35 nm in diameter) can be stably generated at a density of cm⁻³, ensuring the shielding performance of the conductive film. The silicone rubber elastic layer is cured at 135℃ for 45 minutes, balancing curing efficiency and material crosslinking degree. The modified polyimide adhesive layer is sprayed at a pressure of 0.4 MPa to form a uniform coating, and a low-temperature curing time of 60 minutes ensures full curing. The parameter selection prioritizes improving the conductivity and shielding performance of the inner shielding layer 2 and the bonding strength of the buffer adhesive layer 3. The nanometer-diameter silver conductive film of this invention achieves a conductivity of 5 × 10⁻⁶. 7 The elastic modulus of the silicone rubber elastic layer meets the design requirements (S / m), the bonding strength of the buffer adhesive layer 3 reaches 1.8 N / mm, and the interlayer peel force is reduced by 20%.

[0049] Example 7: This example represents a comprehensive optimization of the entire manufacturing process, covering parameters for steps S100, S200, S300, and S400. In step S100, the stranding pitch is 8-12 times the outer diameter of the conductor core 6. The parameters for S200 and S300 are the same as in Examples 5 and 6. Preferred parameter combinations: The stranding pitch for S100 is 10 times the outer diameter of the conductor core 6; the parameters for S200 are the same as the preferred combination in Example 5; the parameters for S300 are the same as the preferred combination in Example 6; and the braiding angle for the outer shielding layer 4 in S400 is 38°, and the braiding density is 97%. Sensor model used: In addition to the sensors used in Examples 5 and 6, the tension sensor used in step S100 is a ZNL-100. Working Process and Principle: In S100, multiple strands of ultra-fine aluminum-magnesium alloy wire are selected and layered and twisted. A tension sensor controls the twisting tension to ensure that the twisting pitch is stable at 10 times. S200 and S300 are carried out according to the processes of Examples 5 and 6. In S400, the outer shielding layer 4 is woven according to the preferred parameters, and the finished product is then processed. Reasons for Preferred Parameters: The twisting pitch of 10 times in S100 balances the flexibility and conductivity of the conductor core 6; the preferred parameters of S200 and S300 have been verified to improve the performance of the insulation layer 1, the shielding layer, and the bonding layer; the outer shielding layer 4 has a weaving angle of 38° and a density of 97%, balancing shielding performance and weaving efficiency. The parameter selection tends to optimize the entire process, ensuring that the parameters of each step are matched and improving the overall performance of the cable. The conductor core 6 of the cable prepared by this invention has stable conductivity, resistance deviation ≤2%, electromagnetic shielding attenuation up to 88dB, and excellent vibration fatigue resistance. 9 No structural damage was observed after one vibration cycle.

[0050] Example 8: This example focuses on the fabrication of cables adapted to extreme environments. The parameter ranges are the same as in Examples 5 and 6, with the preferred parameter combination being: a bonding transition layer thickness deviation control threshold of ±0.005mm, a core insulation layer melt coating melt temperature fluctuation range of ≤±2℃, and a spiral groove texture pitch that is 5 times the core insulation layer thickness; a plasma density of 5×10¹. 5 The nano-silver particles are 50nm in diameter and 0.07mm thick. The silicone rubber elastic layer is cured at 150℃ for 60min. The modified polyimide coating is 0.05mm thick, sprayed at 0.5MPa, with a humidity control threshold >60%, a curing time of 10min, and a low-temperature curing temperature of 100℃ for 80min. The sensors used are: ZTMS10 for online thickness monitoring, OS150 for infrared temperature measurement, HPR-800 for plasma density monitoring, and SHT31 for humidity. The working process and principle are similar to those in Examples 5 and 6, with a focus on enhancing parameter control accuracy and material curing degree. The optimal design features a core insulating layer with a spiral groove texture pitch 5 times greater, increasing the contact area with the inner shielding layer 2 and improving adhesion; a plasma density of 5×10¹.5 The 50nm diameter and 5cm³ silver nanoparticle size allow for the formation of a denser conductive film, enhancing shielding and radiation resistance. The silicone rubber elastic layer and modified polyimide adhesive layer utilize higher curing temperatures and longer curing times to ensure stable performance under extreme temperature conditions. Parameter selection prioritizes improving the cable's adaptability to extreme environments, particularly its radiation resistance and resistance to high and low temperatures. The cable prepared according to this invention can withstand 1.2 × 10⁻⁶ ppm. 8 The radiation dose is low, and the structure maintains good structural integrity and performance stability under extreme temperatures of -200℃ and +260℃. The electromagnetic shielding attenuation reaches 90dB, meeting the requirements for use in extreme environments such as deep space exploration.

[0051] Furthermore, in the cable manufacturing method of the present invention, step S400 further includes:

[0052] S401: The outer shielding layer is woven on the outside of the buffer bonding layer using a high-speed precision weaving process. Silver-plated copper alloy microfilaments are selected as the weaving material. Before weaving, the microfilaments undergo tension pre-adjustment treatment. The tension value of each microfilament is monitored in real time by a multi-channel tension sensor to ensure that the tension deviation of a single microfilament is controlled within ±5%. The system integrates a weaving density monitoring system and a weaving speed closed-loop control system. The porosity and weaving pitch data of the woven mesh are collected in real time by a laser scanning sensor. When the porosity deviates from the preset range of ≤3% or the weaving pitch deviates from the preset value of 6 to 8 times the outer diameter of the conductor core, the spindle speed of the weaving machine and the microfilament feeding speed are automatically adjusted. At the same time, the number of weaving layers is controlled to be 2-3 layers, and the weaving direction between layers is staggered at 90° to ensure the weaving density and interlayer adhesion of the outer shielding layer. Online dust removal is carried out simultaneously during the weaving process. A high-voltage electrostatic dust removal device is used to remove metal debris and dust generated during weaving to prevent impurities from embedding in the woven mesh and affecting the shielding performance.

[0053] S402. After weaving, the braided layer undergoes impregnation and curing treatment using a low-viscosity conductive epoxy resin impregnating agent. A vacuum impregnation process is employed to ensure the impregnating agent fully penetrates the pores of the braided layer. The impregnation system integrates a vacuum sensor and an impregnation timer module to monitor the vacuum level of the impregnation environment in real time and control it within the range of -0.08 to -0.1 MPa. When the vacuum level falls below this range, the system automatically starts the vacuum pump to replenish pressure. After impregnation, the layer is transferred to a constant-temperature curing chamber for segmented curing. A temperature gradient control system is used to achieve segmented control of heating, constant temperature, and cooling. The curing environment temperature is monitored in real time, and temperature fluctuations at each stage are controlled to be ≤±2℃. Simultaneously, a differential scanning calorimeter is used to monitor the curing reaction process in real time. When the reaction conversion rate reaches a preset value of ≥95%, curing is considered complete, ensuring the impregnating agent is fully cured and improving the structural stability and conductive continuity of the braided layer.

[0054] S403. Finished product appearance and dimensional accuracy inspection: Integrating a high-precision vision inspection system and a laser diameter gauge, it comprehensively inspects the outer diameter, roundness, and surface defects of the finished cable, such as scratches, dents, exposed braids, and coating peeling; the laser diameter gauge collects outer diameter data in real time, controlling the outer diameter deviation of the finished product to ≤ ±0.05mm and the roundness error to ≤0.03mm; the vision inspection system automatically identifies surface defects through multi-angle image acquisition and image recognition algorithms. When a defect is detected, the system automatically marks the defect location and issues an alarm signal.

[0055] S404. Comprehensive performance testing of finished products includes shielding effectiveness testing, optical fiber transmission performance testing, mechanical performance testing, and environmental resistance testing in sequence: ① Shielding effectiveness testing uses the coaxial transmission line method to measure shielding effectiveness within a frequency range of 10kHz to 1GHz, ensuring that the shielding effectiveness is not less than 80dB; ② Optical fiber transmission performance testing uses an optical time domain reflectometer to measure the insertion loss and return loss of the optical fiber, controlling the insertion loss to not exceed 0.5dB / km and the return loss to not less than 45dB; ③ Mechanical performance testing includes tensile strength testing, bending performance testing, and abrasion resistance testing. Among them, the tensile strength must reach ≥150MPa, the minimum bending radius must not exceed 10 times the outer diameter of the cable, and the abrasion resistance must be no less than 1000 times / 25mm; ④ Environmental performance tests include high and low temperature cycling tests, radiation resistance tests, and damp heat aging tests. The high and low temperature cycling test conditions are -60℃~150℃ and 10 cycles, the total dose of the radiation resistance test is 100kGy, and the damp heat aging test conditions are 40℃, relative humidity 95% and continuous for 1000h. During the test, the cable performance parameters are monitored in real time to ensure that all performance indicators meet the requirements of aerospace use.

[0056] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A multi-layer shielded optical fiber composite aerospace cable, characterized in that, It includes, from the inside out, an insulating layer, an inner shielding layer, a buffer adhesive layer, and an outer shielding layer; The insulating layer contains a conductor core and an optical fiber bundle, and includes an adhesive transition layer, a core insulating layer, and a radiation protection layer from the inside out. The inner shielding layer includes a nano-silver conductive film and a silicone rubber elastic layer. The nano-silver conductive film is disposed on the inner side of the silicone rubber elastic layer. The inner shielding layer is used to shield electromagnetic signals and buffer vibration. The outer shielding layer is provided with a nickel-copper alloy wire mesh, which works in conjunction with the inner shielding layer to provide an electromagnetic barrier and chemical corrosion protection. The buffer bonding layer is provided with a modified polyimide adhesive layer, which is modified by introducing flexible groups and is used to bond the inner shielding layer and the outer shielding layer. The bonding transition layer is composed of modified polyimide resin, and the bonding transition layer is provided with a recessed groove structure for constraining the internal conductor core and the optical fiber bundle. The core insulation layer is composed of perfluorinated polyether modified polytetrafluoroethylene composite material, and the inner surface of the core insulation layer is provided with a spiral groove texture. The radiation protection layer is composed of phenyl silicone rubber modified polyether ether ketone resin, and annular ribs are integrally formed on the outer surface along the circumferential direction. The annular ribs are distributed at equal intervals. The method for preparing the multi-layer shielded optical fiber composite aerospace cable includes the following steps: S100, Prepare hollow conductor core and complete the bonding and layout of optical fiber bundle; S200: An insulating layer is formed by sequentially forming a bonding transition layer, a core insulation layer, and a radiation protection layer on the outside of the conductor core and the optical fiber bundle. S300. An inner shielding layer is prepared on the outside of the insulating layer and a buffer adhesive layer is coated thereon. S400, The outer shielding layer is woven and formed on the outside of the buffer adhesive layer and then the finished product is processed; S200 includes: S201. An extrusion molding process is used to prepare a bonding transition layer on the outside of the conductor core and the optical fiber bundle. During the molding process, the system integrates an online thickness monitoring sensor and an extrusion speed closed-loop control system to collect the thickness data of the bonding transition layer in real time and compare it with a preset thickness threshold. When the monitored thickness deviates from the threshold, the system automatically adjusts the extruder speed. The adjustment range is linearly positively correlated with the thickness deviation. Simultaneously, a recessed groove structure is pressed. The size of the recessed groove structure matches the cross-sectional size of the conductor core and the optical fiber bundle to control the thickness deviation of the bonding transition layer. S202. A core insulating layer is prepared on the outside of the bonding transition layer using a melt coating process. The temperature of the coating melt is monitored in real time by an infrared temperature sensor to control the temperature fluctuation of the coating melt. At the same time, the depth and pitch of the spiral groove texture on the inner side of the core insulating layer are monitored by a laser contour sensor. When the texture parameters deviate from the preset value, the spiral pattern parameters of the coating mold and the coating travel speed are automatically adjusted to control the pitch of the spiral groove texture on the inner side of the core insulating layer. S203. An anti-radiation protective layer is prepared on the outside of the core insulation layer using injection molding. The system integrates a vision inspection system to identify the forming size and spacing of the annular ribs in real time. Combined with a pressure sensor to collect injection pressure data, when the size and spacing of the annular ribs deviate from the preset value, the system automatically adjusts the injection pressure of the injection molding machine and the mold opening and closing speed. The annular ribs are integrally formed during the molding process, and the forming size and spacing of the annular ribs are controlled.

2. The multi-layer shielded optical fiber composite aerospace cable according to claim 1, characterized in that, The conductor core is hollow and is formed by layering multiple strands of ultra-fine aluminum-magnesium alloy wires. The optical fiber bundle includes polyimide-coated single-mode optical fiber. The optical fiber bundle is evenly distributed along the circumference of the hollow conductor core and is attached to the conductor core. The arc shape of the contact surface between the optical fiber bundle and the conductor core is consistent with the outer surface of the conductor core.

3. The multi-layer shielded optical fiber composite aerospace cable according to claim 1, characterized in that, The total thickness of the inner shielding layer is 0.08mm-0.12mm, wherein the thickness of the nano-silver film is 0.05mm-0.07mm, the thickness of the silicone rubber layer is 0.03-0.05mm, the nano-silver particles have a particle size of 20nm-50nm, and the radiation resistance dose is ≥10. 8 Rad.

4. The multi-layer shielded optical fiber composite aerospace cable according to claim 1, characterized in that, The thickness of the buffer adhesive layer is 0.03mm-0.05mm, the adhesive strength is ≥1.5N / mm, the elongation at break is ≥20%, and the temperature resistance range is -200℃ to +260℃.

5. The multi-layer shielded optical fiber composite aerospace cable according to claim 1, characterized in that, The outer shielding layer has a nickel-copper alloy wire diameter of 0.1mm-0.15mm, a braiding angle of 30°-45°, a braiding density of ≥95%, a shielding attenuation of ≥85dB, and a tensile strength of ≥500MPa.

6. The multi-layer shielded optical fiber composite aerospace cable according to claim 1, characterized in that, The S100 further includes: S101. Select multiple strands of ultra-fine aluminum-magnesium alloy wire and use a layered stranding process to form a hollow conductor core. During the stranding process, control the stranding pitch to be 8-12 times the outer diameter of the conductor core. S102. Select polyimide-coated single-mode optical fiber, cut and arrange it to form an optical fiber bundle, so that the arc shape of the bonding surface between the optical fiber bundle and the conductor core is consistent with the outer surface of the conductor core. S103. The optical fiber bundle is evenly distributed and fixed along the circumference of the hollow conductor core. During the fixing process, a temporary adhesive is used for positioning. After the fixing is completed, the temporary adhesive is removed by pyrolysis.

7. The multi-layer shielded optical fiber composite aerospace cable according to claim 1, characterized in that, The S300 also includes: S301. A nano-silver conductive film is deposited on the outside of the insulating layer using magnetron sputtering. The system integrates a plasma density monitoring sensor and a sputtering power closed-loop control system to monitor the plasma density in the sputtering area in real time. When the density deviates from the preset range, the sputtering power and argon flow rate are automatically adjusted to control the particle size of the nano-silver particles. The deposition thickness is monitored in real time by a quartz crystal microbalance. When the thickness reaches the preset value, the system automatically stops sputtering to control the deposition thickness of the nano-silver conductive film. S302. A silicone rubber elastic layer is prepared on the outside of the nano-silver conductive film using a coating and curing process. The curing environment temperature is monitored in real time by a temperature sensor, and the temperature fluctuation of the curing environment is controlled to control the curing temperature, time, and thickness of the silicone rubber elastic layer. S303. A modified polyimide adhesive layer is coated on the outside of the silicone rubber elastic layer using a spraying process. The system integrates a coating thickness sensor and a spraying pressure closed-loop control system, and collects coating thickness data in real time. When the thickness deviates from the preset range, the spraying pressure and the speed of the spray gun are automatically adjusted to control the coating thickness of the modified polyimide adhesive layer. The humidity of the coating environment is monitored by a humidity sensor. When the humidity deviates from the preset value, the system automatically starts the dehumidification device and adjusts the low-temperature curing time to control the humidity of the coating environment and the low-temperature curing time. After coating, a low-temperature curing treatment is performed to control the temperature and time of low-temperature curing.

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