Carbon fiber full-winding method for patch reinforcement at bottle shoulder of gas cylinder liner

Abstract

The invention discloses a carbon fiber full winding method for patch reinforcement at bottle shoulders of a gas cylinder liner, the gas cylinder liner comprises a cylinder body and two bottle shoulders, the curvature at the bottle shoulders suddenly changes to generate stress concentration, patch reinforcement layers are arranged at the bottle shoulders, an annular winding layer is arranged at the cylinder body, and the annular winding layer and the patch reinforcement layers are seamlessly connected. A spiral winding layer is arranged outside the annular winding layer and the patch reinforcing layer, and the annular winding layer and the spiral winding layer jointly form a carbon fiber composite material winding layer; the method comprises the following steps: step 1, pretreating a gas cylinder liner; 2, analyzing the stress of the gas cylinder; step 3, gas cylinder patch planning; fourthly, the gas cylinder inner container is clamped; step 5, cutting the prepreg sheet; step 6, locally paving the prepreg sheet; and seventhly, the gas cylinder inner container is wound in the annular direction. According to the method, waste of carbon fiber materials is reduced, the weak area of the cylinder shoulder is accurately reinforced, the bearing capacity of the gas cylinder is improved, and meanwhile the thickness and weight of the gas cylinder are reduced.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, specifically to a method for fully wrapping carbon fiber with a patch reinforcement at the shoulder of a gas cylinder liner. Background Technology

[0002] Plastic-lined carbon fiber fully wound composite gas cylinders are widely used in high-pressure gas storage and transportation due to their advantages such as lightweight design, excellent corrosion resistance, and prevention of hydrogen embrittlement. The cylinder shoulder, as a critical load-bearing component, withstands the complex stresses brought by high-pressure gases, and its reinforcement directly determines the cylinder's load-bearing capacity and safety performance. Therefore, shoulder reinforcement is a core aspect of the manufacturing of this type of gas cylinder.

[0003] Existing manufacturing technologies related to cylinder shoulder reinforcement have many technical problems: Traditional winding processes achieve reinforcement through alternating spiral and annular winding, which can meet the basic pressure requirements, but cylinder shoulder reinforcement relies on a large number of winding layers, resulting in serious material waste and insufficient reinforcement precision; the independent reinforcement sheet process requires winding, curing, and cutting with independent molds before bonding to the cylinder shoulder, which is not only complex and inefficient, but the secondary bonding interface is also prone to becoming a weak point, affecting the cylinder's fatigue life and airtightness; the layup optimization process improves the overall performance of the cylinder by adjusting the overall layup sequence and angle, but it does not design localized and precise reinforcement schemes for stress concentration areas on the cylinder shoulder, still relying on global spiral winding layer reinforcement, resulting in poor material utilization and reinforcement targeting; the existing full winding process focuses on the overall layup matching of the cylinder body and end cap, and the cylinder shoulder still uses the traditional spiral winding reinforcement mode, which does not adequately alleviate stress concentration, and does not achieve seamless connection between local reinforcement and overall winding, thus limiting efficiency improvement.

[0004] In summary, existing technologies have failed to effectively solve the core technical problems of excessive carbon fiber waste, insufficient reinforcement precision, and poor load-bearing capacity and weight balance in the bottle shoulder reinforcement process. They are insufficient to meet the application requirements of lightweight, high safety, and low cost of gas cylinders. There is an urgent need to innovate a precise, efficient, and energy-saving bottle shoulder reinforcement process. Summary of the Invention

[0005] The purpose of this invention is to provide a method for reinforcing the shoulder of a gas cylinder with a patch, thereby solving the technical problems of excessive carbon fiber waste, insufficient reinforcement precision, and poor load-bearing capacity and weight balance in the existing technology of reinforcing the shoulder of a gas cylinder with fully wound carbon fiber composite materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for fully wound carbon fiber reinforcement at the shoulder of a gas cylinder liner, wherein the gas cylinder liner includes a cylinder body and two shoulders, where stress concentration occurs due to a sudden change in curvature at the shoulders, a patch reinforcement layer is provided at the shoulders, an annular winding layer is provided at the cylinder body of the gas cylinder liner, the annular winding layer and the patch reinforcement layer are seamlessly connected, and a spiral winding layer is provided outside the annular winding layer and the patch reinforcement layer, the annular winding layer and the spiral winding layer together constitute a carbon fiber composite winding layer; The method includes the following steps: Step 1: Pre-treatment of the gas cylinder liner: The gas cylinder liner is treated using a plasma treatment process; Step 2, Cylinder Stress Analysis: Based on the cylinder design load and the three-dimensional model of the cylinder liner, stress simulation analysis is performed using ANSYS finite element analysis software to solve for the cylinder stress distribution and determine the location of the prepreg sheet to be laid locally at the cylinder shoulder. Step 3, Gas Cylinder Patch Planning: Based on the stress distribution results, use CAD-CAM software to plan the application location, size, shape, layup angle, and number of layers of the prepreg sheets; Step 4: Gas cylinder liner installation: Position and install the pre-treated gas cylinder liner onto the six-axis robot patching equipment; Step 5, Prepreg Sheet Cutting: Connect the carbon fiber and epoxy resin prepreg unidirectional tape to the six-axis robot patching equipment, cut the required prepreg sheets according to the planned prepreg sheet size and shape, and perform rapid visual positioning and weight detection on the cut prepreg sheets. Step 6: Partial Prepreg Laying: The six-axis robot laying equipment picks up qualified prepreg sheets and lays multiple prepreg sheets in sequence according to the planned position and angle. During the laying process, heated pressure rollers are used to compact the sheets to form a patch reinforcement layer. Step 7: Circumferential winding of the cylinder liner: The cylinder liner with the completed local reinforcement layer is transferred to the winding machine for multi-layer circumferential winding of the cylinder body area to form a ring winding layer; Step 8, Spiral winding of the gas cylinder liner: Low-angle spiral winding is performed outside the annular winding layer and the patch reinforcement layer to form a spiral winding layer; Step 9, Heating and Curing: Place the cylinder liner with the completed spiral winding layer in a curing oven and heat and cure it according to the set pre-curing-curing curve; Step 10, Testing: Conduct a water pressure test and airtightness test on the composite material gas cylinder liner after heat curing.

[0007] Preferably, in step one, the plasma power is set to 300-400W, the processing time is set to 3-5min, the processing distance is controlled at 8-12mm, and the surface roughness of the gas cylinder inner liner is controlled at 0.8-1.2μm.

[0008] Preferably, in step three, for high-stress areas (i.e., areas with stress values ​​not less than 80% of the design allowable stress), 4 to 6 layers of prepreg are planned to be laid; for medium-stress areas (i.e., areas with stress values ​​of 50% to 80% of the design allowable stress), 2 to 3 layers of prepreg are planned to be laid; for low-stress areas (i.e., areas with stress values ​​not greater than 50% of the design allowable stress), 1 to 2 layers of prepreg are planned to be laid; the prepreg is fan-shaped or trapezoidal in shape, with a length ranging from 180 to 250 mm and a width ranging from 35 to 60 mm; the layup angle of the prepreg includes 0° and ±45°.

[0009] Preferably, in step four, the six-axis robot patching equipment integrates carbon fiber tape unwinding, laser cutting, vision positioning, weight detection, and patching functions. The laser cutting function is completed by the laser cutting module, the vision positioning function is completed by the camera, and the weight detection function is completed by the electronic scale. The unwinding speed of the six-axis robot patching equipment is set within the range of 0.2 to 0.5 m / min, the laser cutting power is set within the range of 50 to 80 W, the cutting accuracy is controlled within ±0.1 mm, the positioning accuracy of the vision positioning system is ±0.05 mm, and the movement speed of the robotic arm is set within the range of 0.3 to 0.8 m / s.

[0010] Preferably, in step six, the overlap width of two adjacent prepreg sheets is 10-15 mm, and the overlaps are staggered to avoid stress concentration.

[0011] Preferably, in step seven, a CNC fiber winding machine is used to perform multi-layer circumferential winding on the gas cylinder liner that has completed the local reinforcement layer. Before the winding operation, the winding tension is set to 8-10N, the winding speed is 1.2-2m / s, the winding nozzle moving speed is 60-100r / min, the thickness of a single layer of the annular winding layer is 0.5-0.6mm, and the number of layers is 8-12.

[0012] Preferably, the circumferential winding layer directly covers and presses the local reinforcing layer, and the carbon fibers are evenly distributed during the winding process without crossing or overlapping, covering the entire gas cylinder.

[0013] Preferably, in step eight, the spiral winding angle of the low-angle spiral winding is set between 10 and 15° or -15 to -10°, the winding tension is set between 5 and 8 N, the winding speed is set between 1.0 and 1.2 m / s, the thickness of a single spiral winding layer is set between 0.5 and 0.6 mm, and the number of layers is set between 5 and 25.

[0014] Preferably, in step nine, the pre-curing-curing curve is as follows: the temperature is increased from room temperature to between 80 and 90°C at a heating rate of 20-30°C / h, and held at that temperature for 3-5 hours. After the holding period, the temperature is increased from 80-90°C to between 120-130°C at a heating rate of 50-60°C / h, and then allowed to cool naturally to room temperature.

[0015] Preferably, in step ten, the water pressure test pressure is 1.5 times the design working pressure, the pressure holding time is at least 30 seconds, the gas cylinder body should not leak or be obviously deformed, and the leakage of the airtightness test should not be greater than 6 ml / (h*L).

[0016] This invention proposes a novel process for reinforcing the shoulder of gas cylinders, involving automated local patching, winding integration, and integrated curing. The cylinder shoulder reinforcement is formed by winding and pressing uncured prepreg sheets together, and then curing them synchronously with the main structure. There is no secondary bonding interface between the reinforcement and the inner liner or the winding layer, achieving structural integrity. By replacing the global spiral winding with local patching, the core design uses reinforcement material only in the shoulder area where reinforcement is most needed, avoiding fiber redundancy in the middle section of the cylinder. Compared with the traditional spiral winding of more than 30 layers and the layup optimization scheme of CN115355439A, the amount of carbon fiber used can be reduced by 10% to 20%, directly resulting in a significant reduction in raw material costs and a lighter cylinder weight.

[0017] The prepreg sheet is directly applied in an uncured state and then pressed together with a subsequent annular winding layer, ultimately achieving a one-time overall curing. This completely eliminates the weak interfaces caused by independent curing and secondary bonding, ensuring a tight bond between the cylinder shoulder reinforcement layer and the main winding layer. This solves the interface problems associated with technologies such as CN120363445A, and greatly improves the cylinder's fatigue life, impact resistance, and long-term airtight reliability.

[0018] The six-axis robot patch placement equipment is an integrated patch placement device that realizes full-process automation from cutting to placement. It is seamlessly connected with the winding process, which simplifies the production process and eliminates many complex processes such as independent mold making, reinforcing sheet winding, independent curing, and cutting. Compared with the full winding process of CN115164089A, the production cycle is faster and the consistency is better.

[0019] Based on stress cloud diagrams, CAD drawings of plastic inner liners with valve seats, and winding process parameters of gas cylinders, prepreg sheets of different sizes, shapes, and layup sequences can be freely designed to achieve on-demand reinforcement and optimize material distribution. This is something that traditional uniform spiral winding and the overall layup optimization and fixed-shape independent reinforcing sheets of CN115355439A cannot achieve.

[0020] The innovation in the process of attaching the gas cylinder shoulder at the front end allows for the continued use of existing winding machines and curing ovens at the back end, making it easy to modify and integrate into existing Type IV gas cylinder production lines, thus minimizing obstacles to industrialization.

[0021] This invention reduces carbon fiber material waste, precisely reinforces weak areas on the cylinder shoulder, improves the cylinder's load-bearing capacity, and simultaneously reduces the cylinder's thickness and weight. It balances airtightness, interfacial bonding, and fatigue life, solving the technical problems of excessive carbon fiber waste, insufficient reinforcement precision, and poor balance between load-bearing capacity and weight in the reinforcement of the cylinder shoulder of carbon fiber fully wound composite gas cylinders in the prior art. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the carbon fiber fully wound gas cylinder of the present invention; Figure 2 This is a partially enlarged schematic diagram of the shoulder area of ​​the bottle of the present invention; Figure 3 This is a magnified schematic diagram of a portion of the enhanced patch area of ​​the present invention; In the diagram: 1. Valve seat; 2. Gas cylinder liner; 3. Patch reinforcement layer; 4. Annular winding layer; 5. Spiral winding layer; 20. Cylinder body; 21. Cylinder shoulder. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings: like Figures 1-3 The invention illustrates a method for fully wound carbon fiber reinforcement at the shoulder of a gas cylinder liner. The gas cylinder liner 2 includes a cylinder body 20 and two shoulders 21. Stress concentration occurs due to abrupt curvature changes at the shoulders 21. A patch reinforcement layer 3 is provided at the shoulders 21, and an annular winding layer 4 is provided at the cylinder body 20. The annular winding layer 4 and the patch reinforcement layer 3 are seamlessly connected. A spiral winding layer 5 is provided outside the annular winding layer 4 and the patch reinforcement layer 3. The annular winding layer 4 and the spiral winding layer 5 together constitute a carbon fiber composite winding layer.

[0024] The method includes the following steps: Step 1: Pretreatment of the gas cylinder liner 2: The gas cylinder liner 2 is treated with plasma treatment technology. In this example, the plasma power is set to 300-400W, the treatment time is set to 3-5min, the treatment distance is controlled at 8-12mm, and the surface roughness of the gas cylinder liner 2 is controlled at 0.8-1.2μm. This removes surface oil and impurities, improves surface activity, and enhances the bonding force with the subsequent prepreg sheet and winding layer.

[0025] Step 2, Cylinder Stress Analysis: Based on the cylinder design load and the three-dimensional model of the cylinder liner 2, stress simulation analysis is performed using ANSYS finite element analysis software to obtain the cylinder stress distribution and determine the location of the prepreg sheet to be laid locally at the cylinder shoulder 21.

[0026] Step 3: Cylinder Patch Planning: Based on the stress distribution results, combined with the cylinder liner 2 model with valve seat 1 and winding process parameters such as the number of winding layers, winding direction, and winding speed, the CAM of the patch system is used for simulation and modeling to plan the application position, prepreg size, layup angle, and number of layers of prepreg at the cylinder shoulder 21. For high-stress areas, i.e., areas with stress values ​​not less than 80% of the design allowable stress, 4 to 6 layers of prepreg are planned; for medium-stress areas, i.e., areas with stress values ​​of 50% to 80% of the design allowable stress, 2 to 3 layers of prepreg are planned; for low-stress areas, i.e., areas with stress values ​​not greater than 50% of the design allowable stress, 1 to 2 layers of prepreg are planned. The prepreg shape is fan-shaped or trapezoidal, with a length range of 180 to 250 mm and a width range of 35 to 60 mm; the layup angle of the prepreg includes 0° and ±45°. 0° layup is used to withstand axial stress, and ±45° layup is used to withstand shear stress.

[0027] Step 4: Installing the gas cylinder inner liner 2: Position and install the pre-treated gas cylinder inner liner 2 onto the six-axis robot patch mounting equipment; The six-axis robotic patching equipment integrates carbon fiber tape unwinding, laser cutting, vision positioning, weight detection, and patching functions. The laser cutting function is completed by the laser cutting module, the vision positioning function is completed by the camera, and the weight detection function is completed by the electronic scale. The unwinding speed of the six-axis robotic patching equipment is set within the range of 0.2 to 0.5 m / min, the laser cutting power is set within the range of 50 to 80 W, the cutting accuracy is controlled within ±0.1 mm, the positioning accuracy of the vision positioning system is ±0.05 mm, and the robotic arm movement speed is set within the range of 0.3 to 0.8 m / s.

[0028] Step 5: Prepreg Sheet Cutting: The carbon fiber and epoxy resin prepreg unidirectional tapes are connected to a six-axis robotic patch panel. Based on the planned prepreg sheet size and shape, the required prepreg sheets are precisely cut online using a laser cutting module. Nitrogen protection is used during the cutting process. The cut prepreg sheets are then quickly positioned visually and their weight is measured. The nitrogen flow rate is 5–8 L / min to prevent resin scorching at the edges of the prepreg sheets. Weight deviation must be controlled within ±3%.

[0029] Step Six: Partial Prepreg Sheet Laying: The six-axis robotic patch-laying equipment establishes a coordinate system by visually identifying the reference marks on the bottle shoulder 21. It then controls a vacuum suction cup to precisely pick up qualified prepreg sheets and lays them sequentially according to the planned positions and angles. During the laying process, heated pressure rollers are used to compact the sheets, forming the patch reinforcement layer 3. The overlap width between adjacent prepreg layers is 10–15 mm, and the overlaps are staggered to avoid stress concentration. The pressure roller temperature is set to 40–60℃, the pressure to 0.2–0.4 MPa, and the roller speed to 5–10 r / min, ensuring a tight fit between the prepreg sheets and the inner liner curved surface, without bubbles, wrinkles, or curling edges.

[0030] Step 7: Circumferential Winding of Cylinder Inner Liner 2: The cylinder inner liner 2 with the completed local reinforcement layer is transferred to a winding machine for multi-layer circumferential winding of the cylinder body 20 area, forming an annular winding layer 4. Specifically, a CNC fiber winding machine is used to perform multi-layer circumferential winding of the cylinder inner liner 2 with the completed local reinforcement layer. Before winding, the winding tension is set to 8-10N, the winding speed to 1.2-2m / s, the winding nozzle moving speed to 60-100r / min, and the thickness of a single layer of the annular winding layer 4 to be 0.5-0.6mm. The number of layers is 8-12, determined according to the cylinder's wall thickness and load-bearing requirements. The circumferential winding layer directly covers and presses the local reinforcement layer. During the winding process, the carbon fibers are evenly distributed without crossing or overlapping, covering the entire cylinder.

[0031] Step 8: Spiral Winding of the Cylinder Inner Liner 2: A low-angle spiral winding is performed outside the annular winding layer 4 and the patch reinforcement layer 3 to balance some of the axial stress, forming a spiral winding layer 5. The spiral winding angle is set between 10 and 15° or -15 to -10°, the winding tension is set between 5 and 8 N, the winding speed is set between 1.0 and 1.2 m / s, the thickness of a single spiral winding layer 5 is set between 0.5 and 0.6 mm, and the number of layers is set between 5 and 25. During the winding process, the winding angle and pitch are precisely controlled by the CNC system of the winding machine to ensure that the fibers are evenly distributed in the cylinder body 20 and the shoulder area 21.

[0032] Step 9, Heating and Curing: Place the gas cylinder inner liner 2 with the spiral wound layer 5 completed in the curing oven and heat and cure it according to the set pre-curing-curing curve; heat from room temperature to 80-90℃ at a heating rate of 20-30℃ / h and keep it at that temperature for 3-5 hours. After the heat preservation is completed, heat from 80-90℃ to 120-130℃ at a heating rate of 50-60℃ / h and keep it at that temperature for 3-5 hours, and then let it cool naturally to room temperature.

[0033] Step 10, Testing: Conduct a hydrostatic test and airtightness test on the heat-cured composite material gas cylinder liner 2. The hydrostatic test pressure is 1.5 times the design working pressure, and the pressure holding time is at least 30 seconds. The gas cylinder body should not leak or show obvious deformation. The leakage rate in the airtightness test should not exceed 6 ml / (h*L).

[0034] Example 1: Manufacturing a 35MPa-390L Type IV gas cylinder for hydrogen storage The HDPE inner liner was subjected to plasma treatment with a plasma power of 350W, a treatment time of 4 minutes, and a treatment distance of 10mm, achieving a surface roughness of Ra1.0μm. The load boundary conditions were: working pressure 35MPa, allowable pressure 43.75MPa, hydrostatic test pressure 52.5MPa, and minimum burst pressure 78.75MPa. Through ANSYS finite element analysis, it was determined that four layers of T700 carbon fiber / epoxy resin pre-impregnated unidirectional tape (area density 180g / m², resin content 40%) were required to be laid on each of the left and right shoulders 21 of the inner liner 2. Two of these layers were larger sheets (230mm × 55mm) with ±45° layups to cover the main stress areas; the other two layers were smaller sheets (180mm × 35mm) with 0° layups for localized reinforcement. The inner liner of the gas cylinder 2 is fixed to a six-axis robotic patching device. The unwinding speed is set to 0.3 m / min, the laser cutting power to 60 W, the visual positioning accuracy to ±0.05 mm, and the robotic arm movement speed to 0.5 m / s. The device pulls out a 300 mm wide prepreg tape from the roll, laser-cuts it into sheets of the corresponding shape, and after passing visual and weight inspections, picks it up by the suction cup (18 mm diameter, vacuum degree -0.07 MPa) at the end of the six-axis robotic patching device. Under visual guidance, it is precisely laid on the shoulder of the inner liner of the gas cylinder 2 and compacted using a heated pressure roller (temperature 50℃, pressure 0.3 MPa, rotation speed 8 r / min). This process is repeated until all eight layers (four layers on each of the two cylinder shoulders 21) are laid, with an overlap width of 12 mm between adjacent layers, taking 32 minutes. The inner liner 2 of the gas cylinder is transferred to a winding machine. First, ten layers of circumferential winding (T700-24K carbon fiber / epoxy resin wet winding, resin content 30%) are performed with a winding tension of 9N, a winding speed of 1.0m / s (1.2~2m / s), and a threading nozzle movement speed of 72r / min. The single-layer thickness of the circumferential winding layer 4 is 0.6mm, completely covering the cylinder body 20. Subsequently, eight layers of low-angle spiral winding are performed at an angle of ±12°, with a winding tension of 8N and a winding speed of 1.2m / s (1.0-1.2m / s). The single-layer thickness of the spiral winding layer 5 is 0.8mm (0.5~0.6mm), covering the entire area of ​​the inner liner 2. The inner liner 2 is then placed in a curing oven and cured according to the pre-curing-curing curve: the temperature is increased from room temperature to 75℃ at 20℃ / h and held for 3h; then increased to 120℃ at 60℃ / h and held for 4h; finally, it is allowed to cool naturally to room temperature (cooling rate ≤25℃ / h). Then, a water pressure test was conducted at a pressure of 52.5 MPa (35 MPa × 1.5) for 1 minute. After that, an air tightness test was conducted: the leakage rate was ≤6 ml / (h*L), and the test was passed.

[0035] Compared to the benchmark product using traditional sixteen-layer spiral winding + thirteen-layer circumferential winding, Example 1 reduces the total amount of carbon fiber used in the gas cylinder by approximately 18% and the finished product weight by approximately 10%. Hydrostatic burst tests and fatigue tests (cyclic at 78.75 MPa pressure) show that the burst pressure meets the standard (≥87.5 MPa), and the fatigue life is improved by more than 20%.

[0036] Example 2: Simplified variant of Type IV gas cylinder with 20MPa stress level. Similar to the plasma treatment process in Example 1, finite element analysis was used to determine the plan for laying three layers of prepreg sheets (two ±45° layups and one 0° layup) in the bottle shoulder 21 area, with dimensions of 200mm × 45mm. Using the same equipment parameters as in Example 1, the three layers of prepreg sheets were laid, with an overlap of 10mm between adjacent layers. The spiral winding step was omitted, and only ten layers of circumferential winding were performed (parameters same as in Example 1). The strong clamping force generated by the circumferential winding firmly integrated the prepreg sheet area in the bottle shoulder 21 area. The curing process and post-treatment procedures were the same as in Example 1.

[0037] This method further simplifies the process and is suitable for applications where axial load requirements are not extremely stringent. Compared to the fully wound process of CN115164089A, the amount of carbon fiber used is reduced by about 15%, the weight of the finished product is reduced by about 8%, and the cost and efficiency advantages are more obvious. The burst pressure is ≥50MPa, and the fatigue life meets the relevant standard requirements.

[0038] The above embodiments are merely illustrative of the concept and implementation of the present invention and are not intended to limit it. Under the concept of the present invention, technical solutions without substantial changes are still within the scope of protection.

Claims

1. A method for fully wound carbon fiber reinforcement at the shoulder of a gas cylinder liner, wherein the gas cylinder liner includes a cylinder body and two shoulders, and stress concentration occurs due to abrupt curvature change at the shoulders, characterized in that: A patch reinforcement layer is provided at the shoulder of the bottle, and an annular winding layer is provided at the body of the cylinder. The annular winding layer and the patch reinforcement layer are seamlessly connected. A spiral winding layer is provided outside the annular winding layer and the patch reinforcement layer. The annular winding layer and the spiral winding layer together constitute a carbon fiber composite winding layer. The method includes the following steps: Step 1: Pre-treatment of the gas cylinder liner; Step 2, Cylinder Stress Analysis: Based on the cylinder design load and the three-dimensional model of the cylinder liner, stress simulation analysis is performed using ANSYS finite element analysis software to solve for the cylinder stress distribution and determine the location of the prepreg sheet to be laid locally at the cylinder shoulder. Step 3, Gas Cylinder Patch Planning: Based on the stress distribution results, use CAD-CAM software to plan the application location, size, shape, layup angle, and number of layers of the prepreg sheets; Step 4: Gas cylinder liner installation: Position and install the pre-treated gas cylinder liner onto the six-axis robot patching equipment; Step 5, Prepreg Sheet Cutting: Connect the carbon fiber and epoxy resin prepreg unidirectional tape to the six-axis robot patching equipment, cut the required prepreg sheets according to the planned prepreg sheet size and shape, and perform rapid visual positioning and weight detection on the cut prepreg sheets. Step 6: Partial Prepreg Laying: The six-axis robot laying equipment picks up qualified prepreg sheets and lays multiple prepreg sheets in sequence according to the planned position and angle. During the laying process, heated pressure rollers are used to compact the sheets to form a patch reinforcement layer. Step 7: Circumferential winding of the cylinder liner: The cylinder liner with the completed local reinforcement layer is transferred to the winding machine for multi-layer circumferential winding of the cylinder body area to form a ring winding layer; Step 8, Spiral winding of the gas cylinder liner: Low-angle spiral winding is performed outside the annular winding layer and the patch reinforcement layer to form a spiral winding layer; Step 9, Heating and Curing: Place the cylinder liner with the completed spiral winding layer into the curing oven and heat and cure it according to the set pre-curing-curing curve; Step 10, Testing: Conduct a water pressure test and airtightness test on the composite material gas cylinder liner after heat curing.

2. The method for fully winding carbon fiber reinforced with a patch at the shoulder of the gas cylinder liner according to claim 1, characterized in that: In step one, the plasma power is set to 300-400W, the processing time is set to 3-5min, the processing distance is controlled at 8-12mm, and the surface roughness of the gas cylinder liner is controlled at 0.8-1.2μm.

3. The method for fully winding carbon fiber reinforced with a patch at the shoulder of the gas cylinder liner according to claim 1, characterized in that: In step three, for high-stress areas (i.e., areas with stress values ​​not less than 80% of the design allowable stress), 4 to 6 layers of prepreg are planned to be laid; for medium-stress areas (i.e., areas with stress values ​​of 50% to 80% of the design allowable stress), 2 to 3 layers of prepreg are planned to be laid; for low-stress areas (i.e., areas with stress values ​​not greater than 50% of the design allowable stress), 1 to 2 layers of prepreg are planned to be laid. The prepreg sheets are fan-shaped or trapezoidal in shape, with a length ranging from 180 to 250 mm and a width ranging from 35 to 60 mm. The layup angle of the prepreg sheets includes 0° and ±45°.

4. The method for fully winding carbon fiber reinforced with a patch at the shoulder of a gas cylinder liner according to claim 1, characterized in that: In step four, the six-axis robot patching equipment integrates carbon fiber tape unwinding, laser cutting, vision positioning, weight detection, and patching functions. The laser cutting function is completed by the laser cutting module, the vision positioning function is completed by the camera, and the weight detection function is completed by the electronic scale. The unwinding speed of the six-axis robot patching equipment is set within the range of 0.2 to 0.5 m / min, the laser cutting power is set within the range of 50 to 80 W, the cutting accuracy is controlled within ±0.1 mm, the positioning accuracy of the vision positioning system is ±0.05 mm, and the movement speed of the robotic arm is set within the range of 0.3 to 0.8 m / s.

5. The method for fully winding carbon fiber reinforced with a patch at the shoulder of the gas cylinder liner according to claim 1, characterized in that: In step six, the overlap width of two adjacent prepreg sheets is 10-15 mm, and the overlaps are staggered to avoid stress concentration.

6. The method for fully winding carbon fiber reinforced with a patch at the shoulder of the gas cylinder liner according to claim 1, characterized in that: In step seven, a CNC fiber winding machine is used to perform multi-layer circumferential winding on the gas cylinder liner that has completed the local reinforcement layer. Before the winding operation, the winding tension is set to 8-10N, the winding speed is 1.2-2m / s, the winding nozzle moving speed is 60-100r / min, the thickness of a single layer of the annular winding layer is 0.5-0.6mm, and the number of layers is 8-12.

7. The method for fully winding carbon fiber reinforced with a patch at the shoulder of a gas cylinder liner according to claim 6, characterized in that: The circumferential winding layer directly covers and compresses the local reinforcing layer. During the winding process, the carbon fibers are evenly distributed without crossing or overlapping, covering the entire gas cylinder.

8. The method for fully winding carbon fiber reinforced with a patch at the shoulder of a gas cylinder liner according to claim 1, characterized in that: In step eight, the spiral winding angle of the low-angle spiral winding is set between 10 and 15° or -15 to -10°, the winding tension is set between 5 and 8 N, the winding speed is set between 1.0 and 1.2 m / s, the thickness of a single spiral winding layer is set between 0.5 and 0.6 mm, and the number of layers is set between 5 and 25.

9. The method for fully winding carbon fiber reinforced with a patch at the shoulder of a gas cylinder liner according to claim 1, characterized in that: In step nine, the pre-curing-curing curve is specifically as follows: the temperature is increased from room temperature to 80-90°C at a heating rate of 20-30°C / h and held for 3-5 hours. After the holding period, the temperature is increased from 80-90°C to 120-130°C at a heating rate of 50-60°C / h and held for 3-5 hours, and then naturally cooled to room temperature.

10. The method for fully winding carbon fiber reinforced with a patch at the shoulder of a gas cylinder liner according to claim 1, characterized in that: In step ten, the water pressure test pressure is 1.5 times the design working pressure, the pressure holding time is at least 30 seconds, and the gas cylinder body should not leak or be obviously deformed; the leakage of the airtightness test should not be greater than 6 ml / (h*L).

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