Non-pressure-resistant shell main structure of unmanned underwater vehicle and machining method

Abstract

The invention discloses a non-pressure-resistant shell main structure of an unmanned underwater vehicle and a machining method, and relates to the technical field of underwater vehicles. The device comprises a lower shell and frameworks, the lower shell and the frameworks are fixedly connected in an up-and-down buckling mode, a transverse framework and a longitudinal framework are fixedly connected in a mutually perpendicular mode, and metal embedded parts are bonded to the positions, where equipment and a floating material body are installed, of the transverse framework and the longitudinal framework; the shell and the framework are both made of carbon fiber composite materials, a buoyancy material is arranged in the space formed by the shell and the framework, the buoyancy material, the shell and the framework form an integral revolving body streamline structure, and during processing, a modified epoxy gel coat is adopted, so that the performance of the shell is improved by means of blocking of nano-montmorillonite, wear resistance of silicon carbide and toughening of polyurethane microspheres. Water-resistant, wear-resistant and impact-resistant surface protection is provided for the shell, and underwater erosion and collision are resisted; the wettability and binding force with the carbon fiber cloth are improved by adopting the modified epoxy resin, and the mechanical bearing capacity of the composite material is enhanced.

Description

Technical Field

[0001] This invention relates to the field of underwater vehicle technology, specifically to a non-pressure-resistant hull main structure and processing method for an unmanned underwater vehicle. Background Technology

[0002] Unmanned underwater vehicles (UUVs) are important robots used for underwater exploration and precision detection equipment. They are self-propelled underwater vehicles that can perform a variety of tasks by carrying sensors and different mission modules. The non-pressure-resistant hull is an important part of the external main structure of the UUV, providing installation space for internal equipment systems.

[0003] Most existing underwater vehicles employ a closed-structure design for their non-pressure-resistant hulls, meaning the outer shell is a sealed pressure chamber. Because the outer shell is completely sealed, seawater cannot infiltrate the interior, simplifying the internal layout. However, this closed-structure design has several technical drawbacks in practical use: the sealed pressure chamber must withstand a significant pressure difference between the inside and outside, making the selection of outer shell materials difficult, and requiring a considerable thickness, which greatly increases the weight of the closed-structure underwater vehicle. When the underwater vehicle is heavy, not only does the balance become more difficult, but the added balance weight further increases the overall weight. Furthermore, underwater vehicles carry limited energy; a heavier vehicle requires a larger power source, resulting in higher energy consumption and consequently, shorter endurance for existing closed-structure underwater vehicles.

[0004] Currently, some underwater vehicles still have a main structure in the form of an integral metal pressure chamber, a segmented pressure chamber, or a metal frame structure. The main frame structure has a significant impact on the reliability and performance of underwater vehicles. At present, the main frame structure cannot meet the requirements for the operation of unmanned underwater vehicles. It has problems such as the main structure accounting for a high proportion of the overall weight of the vehicle when bearing the same total weight of the vehicle, the load-bearing ratio not meeting the requirements, long manufacturing cycle, and inconvenience for modification.

[0005] Traditionally, when using ordinary epoxy gelcoat and epoxy resin, the epoxy gelcoat's water resistance and corrosion resistance are insufficient. Long-term underwater immersion easily leads to water absorption and penetration, causing aging of the internal carbon fiber composite material. Furthermore, its surface abrasion resistance is poor, and it is easily worn away and exposed by water flow and silt. Epoxy resin is brittle and has weak impact resistance, making it prone to cracking under underwater impact. At the same time, its interfacial bonding with the carbon fiber cloth is poor, easily leading to delamination and affecting the structural load-bearing stability. The two materials do not work well together, and the interface is prone to stress due to differences in water absorption rates or mismatches in thermal expansion and contraction coefficients, causing the gelcoat to fall off and the resin to crack. Ultimately, this significantly reduces the overall protective and load-bearing performance of the shell, making it difficult to meet the requirements of long-term underwater service for unmanned underwater vehicles. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of existing underwater vehicles whose main structure is a skeleton form of integral metal pressure hull, segmented pressure hull, or metal frame structure. Under the same total weight of the vehicle, the main structure accounts for a high proportion of the overall weight of the vehicle, the load-bearing ratio does not meet the requirements, and the manufacturing cycle is long. Therefore, this invention provides a non-pressure hull main structure for unmanned underwater vehicles.

[0007] The technical solution adopted by the present invention to solve the above problems is: a non-pressure-resistant hull main structure for an unmanned underwater vehicle, including a lower hull and a frame, wherein the lower hull and the frame are fixedly connected, and the frame includes a longitudinal frame and a transverse frame; metal embedded parts are provided on both the longitudinal frame and the transverse frame; the material of both the lower hull and the frame is carbon fiber composite material.

[0008] The longitudinal frame is provided with a first latch, and the transverse frame is provided with a second latch, the first latch and the second latch engaging with each other; the longitudinal frame and the transverse frame are arranged perpendicular to each other and are bonded together.

[0009] A transverse rib is provided between the transverse frames, a longitudinal frame slot is provided on the longitudinal frame, and a rib block is provided on the transverse rib. The longitudinal frame slot and the rib block are engaged and matched. The longitudinal frame and the transverse rib are arranged perpendicular to each other and are bonded together.

[0010] Multiple sets of frame angle irons are installed around the connection points of the longitudinal and transverse frames. The frame angle irons are connected to the longitudinal and transverse frames by frame bolts. Each set of frame angle irons includes four frame angle irons, which are respectively set at the four corners of the frame connection point.

[0011] Furthermore, the transverse frame is installed at the bow and stern of the aircraft, dividing the aircraft hull formed by the non-pressure hull main structure into a bow section, a midship section, and a stern section; a spreader seat is respectively installed at the top of the transverse frame at the bow and stern, the transverse frame is provided with a third latch, the spreader seat is provided with a spreader seat latch, the third latch and the spreader seat latch are engaged; the spreader seat is fixed to the transverse frame around its perimeter by spreader seat angle irons.

[0012] Furthermore, the metal embedded part has a top-bottom circular structure, including a square embedded part and a circular embedded part. The circular embedded part is provided with a connecting hole, and the frame is provided with a corresponding top-bottom circular embedded hole. The metal embedded part is installed in the embedded hole and fixedly connected to the frame.

[0013] Another technical solution adopted by the present invention to solve the above problems is: a method for processing a non-pressure-resistant hull of an unmanned underwater vehicle, comprising the following steps:

[0014] Step 1 S100: Make the male mold of the shell; Step 2 S200: Make the female mold of the shell; Step 3 S300: Make the shell; Step 4 S400: Make the skeleton;

[0015] Step 5 S500: Assemble the shell and frame into a non-pressure-resistant shell main structure, including the following steps:

[0016] S510. Cut carbon fiber cloth according to the size parameters of the shell and frame, then bond and assemble the shell and frame and set the embedded parts to assemble the main shell structure.

[0017] S520. Grinding of the main shell structure: Use 240-grit sandpaper to grind the shell and frame of the main shell structure as a whole.

[0018] S530: Spray epoxy primer onto the sanded main structure of the shell, cure for 8-24 hours, and then sand with 240-grit sandpaper; repeat step S530 twice.

[0019] S540. Apply topcoat to the sanded main structure of the shell.

[0020] Further, step one S100, which involves fabricating the male mold for the shell, includes the following steps:

[0021] S110. Based on the shell dimensions of 20mm, arrange the engraving machine drawings from head to tail in sequence.

[0022] S120. Input the layout drawing into the engraving machine and process the 20mm PVC foam board in sequence;

[0023] S130. The processed PVC foam boards are glued together in sequence to form a positive mold.

[0024] S140. Use a grinder and 80-grit, 240-grit, and 400-grit sandpaper to grind the bonded positive mold in sequence, and re-measure the positive mold according to the size requirements.

[0025] S150 mixed body filler is applied to the entire surface of the positive mold by scraping and coating with body filler.

[0026] S160. Use a sander and 80-grit, 240-grit, and 400-grit sandpaper to sand the putty in sequence.

[0027] S170. Spray epoxy primer onto the positive mold after it has been sanded and coated with putty.

[0028] S180. After painting, the positive mold is polished with 240-grit and 400-grit sandpaper in sequence.

[0029] Furthermore, step two S200, which involves creating the shell female mold, includes the following steps:

[0030] S210. Cut fiberglass cloth according to the size of the positive mold and the thickness of the negative mold.

[0031] S220: Apply release wax to the surface of the male mold, and polish it with a cotton cloth after 10-20 minutes; repeat S220 three times.

[0032] S230 After the release wax process is completed, apply release agent to the surface of the male mold. After the release agent has dried, apply a second release agent.

[0033] S240. After the release agent surface is air-dried, mix the epoxy gel coat and apply the epoxy gel coat to the male mold for the first time. After the epoxy gel coat surface is air-dried, apply the epoxy gel coat for the second time.

[0034] The epoxy gel coat undergoes modification treatment, and the preparation steps are as follows:

[0035] Step 1: Take 3 parts of nano-montmorillonite, add 0.5 parts of KH-560 coupling agent dissolved in 10 parts of anhydrous ethanol, stir at 300 rpm for 30 min in a 50℃ water bath to allow the ethoxy-OC2H5 of the coupling agent to react with the hydroxyl-OH on the surface of montmorillonite; then dry in an 80℃ oven for 2 h to remove ethanol and obtain coupling agent modified montmorillonite; take 10 parts of silicon carbide micro powder, add 1.5 parts of KH-560 coupling agent dissolved in 20 parts of anhydrous ethanol, ultrasonically disperse at 300W power for 15 min, then filter, and dry in an 80℃ oven for 1 h to coat the surface of silicon carbide with coupling agent molecules;

[0036] Step 2: Pour 100 parts of epoxy gel coat resin into a mixing tank, preheat in a 40°C water bath for 10 minutes, and stir at 500 rpm. Add the coupling agent-modified montmorillonite to the epoxy gel coat resin, increase the stirring speed to 1500 rpm, and shear and disperse for 20 minutes. Add 10 parts of pretreated silicon carbide micro powder, continue stirring and shearing at 1500 rpm for 15 minutes, then add 6 parts of polyurethane microspheres, reduce the speed to 1000 rpm, and stir for 10 minutes.

[0037] Step 3: Add 0.2 parts of polyether modified silane leveling agent and 0.1 parts of organosilicon defoamer to the mixture, and stir at 800 rpm for 5 minutes to ensure uniform dispersion of the additives.

[0038] Step 4: Mix the epoxy gel coat resin and T31 modified curing agent at a weight ratio of 100:15, and stir at 500 rpm for 3 minutes to obtain the modified epoxy gel coat.

[0039] S250. After the epoxy gel coat surface has dried, mix epoxy resin, curing agent and toughening agent; first lay a 0.2mm glass fiber cloth, then scrape a layer of mixed epoxy resin; then lay a 0.4mm glass fiber cloth and scrape a layer of mixed epoxy resin in sequence; achieve the thickness of the female mold according to the size requirements of the female mold, and cure after the female mold is pasted;

[0040] The epoxy resin undergoes modification treatment, and the preparation steps are as follows:

[0041] Step 1: Add 5 parts of nano silica to 2 parts of KH-560 coupling agent dissolved in 10 parts of anhydrous ethanol, stir at 400 rpm for 30 min in a 60℃ water bath to allow the ethoxy-OC2H5 of the coupling agent to react with the hydroxyl-OH on the surface of the nano silica, dry in an 80℃ oven for 2 h to remove ethanol, and obtain KH-560 modified nano silica.

[0042] Step 2: Heat 100 parts of epoxy resin to 60°C, add 8 parts of carboxyl liquid nitrile rubber, stir at 800 rpm for 20 minutes, then heat to 80°C and stir for 30 minutes to obtain epoxy resin-carboxyl liquid nitrile rubber system.

[0043] Step 3: Add the modified nano-silica to the epoxy resin-carboxylated liquid nitrile rubber system, increase the rotation speed to 1500 rpm, shear and disperse for 20 min, add 2 parts of KH-560 coupling agent, reduce the rotation speed to 800 rpm and stir for 10 min.

[0044] Step 4: Add 5 parts of benzyl glycidyl ether reactive diluent, stir for 10 minutes and adjust the viscosity to 5000 mPa·s. Mix the epoxy resin and T31 modified amine curing agent at a weight ratio of 100:15 and stir at 500 rpm for 3 minutes to complete the modification of the epoxy resin.

[0045] S260. After the female mold has cured for the time specified in step five, punch holes in the female mold and use an air pump to pressurize and demold the female mold from the male mold. Then, measure the female mold again according to the size requirements.

[0046] S270. After demolding, the surface of the female mold is treated with 240-grit wet sandpaper, and then treated with 400-grit wet sandpaper.

[0047] Furthermore, step three S300, which involves manufacturing the housing, includes the following steps:

[0048] S310. Cut carbon fiber cloth and vacuum bags according to the size of the female mold;

[0049] S320: Apply release wax to the surface of the female mold, and polish it with a cotton cloth after 10-20 minutes; repeat S320 three times.

[0050] S330 After the release wax process is completed, apply release agent to the surface of the female mold. After the release agent has dried, apply a second release agent.

[0051] S340. After the release agent surface is air-dried, mix the epoxy gel coat and apply the epoxy gel coat to the female mold for the first time. After the epoxy gel coat surface is air-dried, apply the epoxy gel coat for the second time.

[0052] S350. After the epoxy gel coat surface has dried, mix epoxy resin, curing agent and toughening agent. First, lay a 0.2mm carbon fiber cloth, then scrape a layer of mixed epoxy resin. Then lay a 0.4mm carbon fiber cloth, then scrape a layer of mixed epoxy resin, to achieve the shell thickness according to the shell size.

[0053] Then, first lay a layer of release cloth on the surface of the pasted carbon fiber cloth, then lay a layer of absorbent cotton, seal the female mold with vacuum bags and sealing strips, leave an air vent, and use a vacuum pump to vacuum-press and solidify the female mold.

[0054] S360. After curing, drill holes in the female mold, use an air pump to pressurize and demold the shell, and cut the excess part of the shell according to the size requirements using an angle grinder.

[0055] S370. Finally, the surface of the casing is treated with 240-grit sandpaper and wet sanding.

[0056] Furthermore, step four, S400, of fabricating the skeleton includes the following steps:

[0057] S410. Process carbon fiber sheets for the skeleton using vacuum bag compression molding process according to the skeleton size.

[0058] S420: Arrange multiple skeleton components into a single carbon fiber sheet, and then use a carving machine to process the carbon fiber sheet into multiple skeleton components.

[0059] S430, Finally, assemble the processed carbon fiber plate skeleton components into a skeleton, and then grind them.

[0060] Furthermore, in step five of the process of making the shell female mold, the mold paste is cured after completion, and the curing time is 24-48 hours.

[0061] Furthermore, in step five of the shell fabrication process, a vacuum pump is used to vacuum bag press-fit the female mold, with the vacuum bag pressing and holding time ranging from 3 to 10 hours and the curing time from 24 to 48 hours.

[0062] The present invention has the following beneficial technical effects:

[0063] The main structure of this underwater vehicle uses a shell and frame made of carbon fiber composite material. The shell and frame form an open structure, providing ample space for placing equipment. The shell and frame design facilitates manufacturing. The carbon fiber composite material is corrosion-resistant in seawater and maintenance-free. It also allows for the embedding of metal parts, facilitating the installation and fixing of equipment and buoyancy. The open upper space formed by the splicing of the lower shell and frame allows for the installation of buoyancy within the rib spacing. The buoyancy is completely covered with carbon fiber composite material for protection. Embedded parts are installed on the frame in a square shape with a rounded top and a rounded bottom, which prevents the embedded parts from falling out due to the weakening of the adhesive over time. The square head is larger than the round head, securing it within the frame and preventing the embedded parts from falling out of the round holes.

[0064] The non-pressure-resistant main structure of the underwater navigator of this invention, including the shell and frame, is made of carbon fiber using a vacuum bag pressing process. Compared to other metal shells, it is lighter and does not corrode in seawater. This invention uses vacuum bag pressing to manufacture the shell and frame, reducing the weight of the non-pressure-resistant shell and minimizing subsequent machining processes.

[0065] The skeleton of this invention employs two longitudinal skeletons and two transverse skeletons, which are perpendicular to each other to form a grid-like frame structure. The frame structure is bonded to the lower shell. The longitudinal skeletons and the two transverse skeletons are connected by snap-fit ​​joints and then bonded together. Multiple sets of angle irons are arranged around the connection points of the longitudinal and transverse skeletons, with each angle iron positioned at one of the four corners of the connection point and secured with bolts, effectively improving structural stability and load-bearing capacity. The lower shell and skeleton are made of carbon fiber, which reduces the weight of the main shell structure while effectively increasing the load-bearing capacity. The underwater vehicle has a compact structure, improving its reliability and submersible performance. The structural design and corresponding processing technology of this invention result in a main shell structure with a self-weight of less than 400 kg, a static working load capacity of 3 tons, and a total structural load capacity of not less than 6 tons under lifting conditions.

[0066] This invention employs a modified epoxy gelcoat. KH-560-modified nano-montmorillonite forms a labyrinthine water molecule barrier network within the gelcoat, combined with dense filling of silicon carbide micropowder, reducing the gelcoat's water absorption rate. When immersed in seawater for extended periods, its corrosion resistance is extended, effectively resisting underwater ion penetration and microbial erosion. The silicon carbide micropowder reduces surface wear, allowing it to withstand water flow and sediment erosion. The core-shell structure of the polyurethane microspheres absorbs impact energy through flexible core deformation, increasing the gelcoat's elongation at break and impact resistance, preventing cracks from underwater collisions. The KH-560 coupling agent achieves chemical bridging between the gelcoat and the subsequent epoxy resin matrix, improving interfacial peel strength. Leveling agents and defoamers ensure a smooth, bubble-free surface during gelcoat application, providing a uniform protective layer for the shell.

[0067] This invention utilizes modified epoxy resin, with carboxyl-based liquid nitrile rubber forming a block structure with the epoxy resin, thereby increasing the resin's elongation at break. KH-560 modified nano-silica forms nano-pinning points in the resin, enhancing and maintaining its tensile strength, achieving a balance of strong and tough mechanical properties. One end of the KH-560 coupling agent reacts with the epoxy resin, while the other end can bond with the coupling agent groups of the nanofillers in the modified epoxy gel coat, enhancing the interfacial bonding between the resin and the gel coat. The reactive diluent reduces the resin viscosity, improving the wettability of the carbon fiber cloth and increasing the pull-out strength of the carbon fiber monofilaments, ensuring the load-bearing capacity of the carbon fiber composite material. The hydrophobic network of nano-silica synergizes with the water-resistant system of the modified gel coat, resulting in low water absorption of the epoxy resin, consistent with the water resistance of the gel coat, preventing delamination failure due to interfacial water absorption in underwater environments. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the non-pressure-resistant main structure of the present invention;

[0069] Figure 2 This is a top view of the non-pressure-resistant main structure of the present invention;

[0070] Figure 3 This is a cross-sectional view of the underwater vehicle to which this invention applies;

[0071] Figure 4 This is an isometric view of an underwater vehicle to which this invention is applicable;

[0072] Figure 5 This is a structural schematic diagram of a metal embedded part;

[0073] Figure 6 This is a cross-sectional view of the connection structure of the metal embedded parts;

[0074] Figure 7 This is a partial structural diagram of the non-pressure-resistant main structure for installing buoyancy materials;

[0075] Figure 8 This is a partial structural diagram of the non-pressure-resistant main structure;

[0076] Figure 9 This is a structural diagram of the frame angle iron;

[0077] Figure 10 This is a structural schematic diagram of the angle iron frame connecting bolts;

[0078] Figure 11 yes Figure 10 A magnified view of a portion of the image;

[0079] Figure 12 This is an exploded structural diagram of the present invention;

[0080] Figure 13This is a schematic diagram of the male and female mold structures used in the shell processing of this invention;

[0081] Figure 14 This is a schematic diagram of the structure of the vacuum bag pressure shell female mold;

[0082] Figure 15 This is a structural schematic diagram of a carbon fiber skeleton plate;

[0083] In the diagram, 1. Upper hull; 11. Bow section upper hull; 12. Midship section upper hull; 13. Stern section upper hull; 14. Inspection hull cover; 2. Lower hull; 3. Skeleton; 31. Longitudinal skeleton; 32. Transverse skeleton; 33. Transverse rib; 34. Longitudinal skeleton slot; 35. Rib block; 36. First bayonet; 37. Second bayonet; 38. Third bayonet; 4. Main propeller hull; 5. Buoyancy material; 6. Metal embedded parts; 61. Square embedded part; 62. Circular embedded part; 63. Connecting hole; 7. Lifting gear seat; 71. Lifting gear seat bayonet; 8. Lifting gear seat angle iron; 9. Skeleton bolt; 91. First skeleton bolt; 92. Second skeleton bolt; 93. Third skeleton bolt; 94. Fourth skeleton bolt; 10. Skeleton angle iron. Detailed Implementation

[0084] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0085] Specific Implementation Method 1: The purpose of this invention is to solve the problems of existing underwater vehicles where the main structure is a single metal pressure tank, segmented pressure tanks, or a metal frame structure. These structures, using large-area thin-walled shells, suffer from the problem that the main structure accounts for a high proportion of the overall weight of the vehicle while bearing the same total weight. Furthermore, they are time-consuming, expensive, and difficult to modify. The invention addresses these issues by using a shell and frame made of carbon fiber composite materials with an open structure that provides ample space for equipment placement. The frame design facilitates fabrication, and the carbon fiber composite material is corrosion-resistant in seawater and maintenance-free. The carbon fiber composite material also allows for quick and easy fabrication and modification by embedding metal parts or drilling holes. The open upper space formed by the splicing of the lower shell and the frame facilitates the installation of the floating material within the rib spacing. The floating material itself is covered with carbon fiber composite material for protection. The embedded parts are bonded to the frame in a top-rounded shape, preventing them from falling out due to adhesive failure over time. The square head is larger than the round head, securing it within the frame and preventing it from falling out of the round hole, thus providing a reliable main structure for an unmanned underwater vehicle.

[0086] In this embodiment, the main structure of the underwater vehicle's non-pressure-resistant hull includes a lower hull 2 ​​and a frame 3. The lower hull 2 ​​and the frame 3 are fixed together by adhesive bonding. The transverse and longitudinal frames are fixed perpendicularly to each other. Metal embedded parts 6 are bonded to the transverse and longitudinal frames at the locations where equipment and buoyancy materials are installed. The shape of the metal embedded parts 6 is that of a square top and a round bottom, with a relatively small thickness at the square head. The thickness of the metal embedded parts 6 is the same as that of the transverse and longitudinal frames. The frame 3 has openings that are also round top and round bottom, with dimensions slightly larger than the corresponding square and round dimensions of the metal embedded parts 6, so that the metal embedded parts 6 can only be inserted through the square holes. The round embedded part 62 is oriented towards the direction of the fixing screw, and the metal embedded part 6 is fixed to the frame 3. Buoyancy material 5 is provided within the gap formed by the transverse frame 32 and the transverse ribs 33. The surface of the buoyancy material 5 is covered with carbon fiber composite material, and the buoyancy material 5 and the hull form an integral rotating streamlined structure with the frame.

[0087] Combination Figures 1 to 15 This embodiment describes a non-pressure-resistant hull main structure for an underwater vehicle, comprising a lower hull 2 ​​and a frame 3, wherein the lower hull 2 ​​and the frame 3 are fixedly connected, and the frame 3 comprises a longitudinal frame 31 and a transverse frame 32; metal embedded parts 6 are provided on both the longitudinal frame 31 and the transverse frame 32; both the lower hull 2 ​​and the frame 3 are made of carbon fiber composite material.

[0088] The longitudinal frame 31 is provided with a first latch 36, and the transverse frame 32 is provided with a second latch 37. The first latch 36 and the second latch 37 are engaged and matched. The longitudinal frame 31 and the transverse frame 32 are arranged perpendicular to each other and are bonded together.

[0089] A transverse rib plate 33 is also provided between the transverse skeletons 32. A longitudinal skeleton slot 34 is provided on the longitudinal skeleton 31. A rib plate block 35 is provided on the transverse rib plate 33. The longitudinal skeleton slot 34 and the rib plate block 35 are engaged and cooperated. The longitudinal skeleton 31 and the transverse rib plate 33 are arranged perpendicular to each other and are bonded together.

[0090] Multiple sets of frame angle irons 10 are provided around the connection point of the longitudinal frame 31 and the transverse frame 32. The frame angle irons 10 are connected to the longitudinal frame 31 and the transverse frame 32 by frame bolts 9. Each set of frame angle irons 10 includes four frame angle irons 10, which are respectively set at the four corners of the connection point of the frame 3.

[0091] In this embodiment, the frame 3 includes two longitudinal frames 31 and two transverse frames 32, which are perpendicular to each other. The two longitudinal frames 31 are arranged in parallel, and the two transverse frames 32 are arranged in parallel and fixedly connected to the longitudinal frames 31 respectively, forming a grid-shaped frame structure. The frame structure is then bonded to the lower shell 2. The longitudinal frames 31 and the two transverse frames 32 are also bonded together after being installed by snap-fit. Multiple sets of frame angle irons 10 are arranged around the connection point of the longitudinal frames 31 and the transverse frames 32 and connected by frame bolts 9. Each set of frame angle irons 10 includes four frame angle irons 10, which are respectively set at the four corners of the connection point of the frame 3. The frame bolts 9 on the frame angle irons 10 lock the frame 3 in four directions. The frame bolts 9 used to connect the frame angle irons 10 to the frame are the first frame bolt 91, the second frame bolt 92, the third frame bolt 93, and the fourth frame bolt 94, which lock the longitudinal frames 31 and the transverse frames 32 from four directions respectively.

[0092] In this embodiment, the overall self-weight of the main shell structure is less than 400KG. After installing equipment and buoyancy materials, the static working load reaches 3T. The total load-bearing capacity of the structure under lifting conditions is not less than 6T. After being lifted and landed, the maximum overall deformation in the free state is less than 2mm. After the crane lifts a 6t load, the structure stabilizes after staying in the air for 5 minutes, and there are no abnormalities in the threaded holes.

[0093] In a preferred embodiment, the transverse frame 32 is disposed at the bow and stern of the aircraft, and the transverse frame 32 divides the aircraft hull formed by the non-pressure hull main structure into a bow section, a midship section and a stern section; a spreader seat 7 is respectively disposed at the top of the transverse frame 32 at the bow and stern, the transverse frame 32 is provided with a third latch 38, the spreader seat 7 is provided with a spreader seat latch 71, the third latch 38 and the spreader seat latch 71 are engaged; the spreader seat 7 is fixed to the transverse frame 32 around its perimeter by spreader seat angle irons 8.

[0094] In a preferred embodiment, the metal embedded part 6 has a top-bottom circular structure, including a square embedded part 61 and a circular embedded part 62. The circular embedded part 62 is provided with a connecting hole 63, and the skeleton 3 is provided with a corresponding top-bottom circular embedded hole. The metal embedded part 6 is installed in the embedded hole and fixedly connected to the skeleton 3.

[0095] In a preferred embodiment, the metal embedded part 6 has a top-bottom circular structure, including a square embedded part 61 and a circular embedded part 62. The circular embedded part 62 has a connecting hole 63. The thickness of the metal embedded part 6 is the same as that of the skeleton 3. The skeleton 3 has corresponding top-bottom circular embedded holes, and the metal embedded part 6 and the skeleton 3 are fixedly connected. The side length of the square embedded part 61 is larger than the diameter of the circular embedded part 62. The connecting hole 63 is a screw hole for installing electronic equipment, sealing chambers, and buoyancy materials. The directional terms "top" and "bottom" in "top-bottom circular" are only for the convenience of describing the metal embedded part 6 and do not indicate a specific orientation that the device or structure must have.

[0096] The main structure of the unmanned underwater vehicle's non-pressure hull also includes an upper hull 1, which is a multi-section, unsealed open structure, and a lower hull 2, which is a three-section, unsealed open structure. The main thruster hull 4 is fixedly connected to the tail of the lower hull 2. The upper hull 1 and the lower hull 2 ​​are fixedly connected to the frame 3 via an upper-lower interlocking mechanism. The non-pressure hull of this underwater vehicle is designed with a streamlined shape to minimize drag.

[0097] The main structure of the underwater vehicle of this invention includes an upper shell 1, with a frame 3 serving as the main load-bearing component. The upper shell 1 and lower shell 2 are respectively fixedly connected to the frame 3. The shell is used to provide a streamlined shape and reduce resistance during underwater navigation. The non-pressure-resistant outer shell of this invention is an open structure with segmented upper shell 1. The upper shell 1 is sequentially connected and fixedly connected to the frame 3. The upper shell 1 is a non-load-bearing structure that protects the internal equipment of the vehicle. The outer shell is not sealed, and the vehicle's cabin is flooded. Only critical components inside the cabin are encased in a pressure-resistant shell.

[0098] Specific Implementation Method Two: Combining Figures 1 to 15 This embodiment describes a frame 3 comprising two longitudinal frames 31 and two transverse frames 32, which are perpendicular to each other. The two longitudinal frames 31 are arranged in parallel, and the two transverse frames 32 are arranged in parallel and fixedly connected to the longitudinal frames 31 respectively, forming a grid-shaped frame structure and creating a three-section cabin: front, middle, and rear.

[0099] In a preferred embodiment, the upper shell 1 comprises the bow section shell, midship section shell, and stern section shell, corresponding to the bow section, midship section, and stern section, respectively. The bow section shell is composed of multiple bow section upper shells 11 and bow section lower shells 2 joined together vertically. The midship section shell is composed of multiple midship section upper shells 12 and midship section lower shells 2 joined together vertically. The stern section shell is composed of multiple stern section upper shells 13 and stern section lower shells 2 joined together vertically. One of the multiple bow upper shells 11 is a maintenance shell cover 14. Multiple transverse ribs 33 are spaced apart inside the bow section, midship section, and stern section to increase the overall load-bearing capacity of the frame 3.

[0100] The frame 3 of this invention serves as the main load-bearing structure, and the instruments, equipment, and various pressure-resistant sealed compartments inside the underwater vehicle are all fixed to the frame 3. In this embodiment, a main thruster housing 4 is also installed at the tail of the lower hull 2. The main thruster housing 4 is made of carbon fiber through a machining process.

[0101] This embodiment of the underwater vehicle adopts an open structure design for its non-pressure-resistant outer shell, which balances the internal and external pressures of the outer shell, reduces the shell thickness and material selection difficulty, lowers the weight of the underwater vehicle, reduces the difficulty of test balancing, and increases endurance. The upper and lower shells of this invention are fixed to the frame using an interlocking mechanism, ensuring reliable connection, high volume utilization, convenient assembly and disassembly, good adaptability, easy replacement and modification, and low maintenance costs.

[0102] The other components and connections are the same as in Specific Implementation Method 1.

[0103] Specific implementation method three: Combining Figures 1 to 15 This embodiment describes a method for processing a non-pressure-resistant hull for an unmanned underwater vehicle, comprising the following steps:

[0104] Step 1 (S100): Fabricate the male mold of the shell; Step 2 (S200): Fabricate the female mold of the shell; Step 3 (S300): Fabricate the shell; Step 4 (S400): Fabricate the frame; Step 5 (S500): Assemble the shell and frame into the main structure of the non-pressure-resistant shell, including the following steps:

[0105] S510. Cut carbon fiber cloth according to the size parameters of the shell and frame, then bond and assemble the shell and frame and set the embedded parts to assemble the main shell structure.

[0106] S520. The shell and frame of the main shell structure are sanded as a whole, using 240-grit sandpaper.

[0107] S530. Spray epoxy primer onto the sanded main structure of the shell, cure for more than 8 hours, and then sand with 240-grit sandpaper; repeat step S530 twice.

[0108] S540. Apply topcoat to the sanded main structure of the shell.

[0109] In this embodiment, the carbon fiber non-pressure resistant shell is manufactured using a vacuum bag pressing process. Vacuum bag pressing refers to placing the part inside a vacuum bag and using a vacuum method to solidify it under vacuum pressure. The vacuum bag is made of a high-strength, ductile material, with an adhesive sealing strip bonded to the mold. The part attached to the mold is wrapped inside the bag, and a gas-guiding felt is placed inside the bag to ensure unobstructed vacuum pathways. The bag is equipped with a vacuum nozzle that can be connected to a vacuum pump via a conduit.

[0110] Specific implementation method four: Combination Figures 1 to 15 This embodiment describes step one (S100) of fabricating the male mold for the shell, which includes the following steps:

[0111] S110. Based on the shell dimensions of 20mm, arrange the engraving machine drawings from head to tail in sequence.

[0112] S120. Input the layout drawing into the engraving machine and process the 20mm PVC foam board in sequence;

[0113] S130. The processed PVC foam boards are glued together in sequence to form a positive mold.

[0114] S140. Use a grinder and 80-grit, 240-grit, and 400-grit sandpaper to grind the bonded positive mold in sequence, and re-measure the positive mold according to the size requirements.

[0115] S150, mix the body filler according to the ratio, and apply the body filler to the entire surface of the positive mold.

[0116] S160. Use a grinder and 80-grit, 240-grit, and 400-grit sandpaper to sequentially treat the putty with water-sand.

[0117] S170. Spray epoxy primer onto the positive mold after it has been treated with putty and water sand.

[0118] S180. After painting, the positive mold is polished with 240-grit and 400-grit sandpaper in sequence.

[0119] In this embodiment, the male mold of the shell is made of PVC foam board, also known as PVC foam board or Andy board. It is made primarily of polyvinyl chloride, with added foaming agents, flame retardants, and anti-aging agents, and is extruded using specialized equipment. PVC foam board has special properties such as not deforming, not cracking, and not requiring painting, while low-foaming boards can be welded, printed with ink, and machined using methods such as sawing, drilling, and milling.

[0120] The other components and connections are the same as in Specific Implementation Method 3.

[0121] Specific Implementation Method Five: Combining Figures 1 to 15 This embodiment describes step two, S200, of fabricating the shell female mold, which includes the following steps:

[0122] S210. Cut fiberglass cloth according to the size of the positive mold and the thickness of the negative mold.

[0123] S220: Apply release wax to the surface of the male mold, and polish it with a cotton cloth after 10-20 minutes; repeat S220 three times.

[0124] S230 After the release wax process is completed, apply release agent to the surface of the male mold. After the release agent has dried, apply a second release agent.

[0125] S240. After the release agent surface is air-dried, mix the epoxy gel coat according to the ratio, and use a scraper to apply the epoxy gel coat to the male mold for the first time. After the epoxy gel coat surface is air-dried, apply the epoxy gel coat for the second time.

[0126] The epoxy gel coat undergoes modification treatment, and the preparation steps are as follows:

[0127] Step 1: Take 3 parts of nano-montmorillonite, add 0.5 parts of KH-560 coupling agent dissolved in 10 parts of anhydrous ethanol, stir at 300 rpm for 30 min in a 50℃ water bath to allow the ethoxy-OC2H5 of the coupling agent to react with the hydroxyl-OH on the surface of montmorillonite; then dry in an 80℃ oven for 2 h to remove ethanol and obtain coupling agent modified montmorillonite; take 10 parts of silicon carbide micro powder, add 1.5 parts of KH-560 coupling agent dissolved in 20 parts of anhydrous ethanol, ultrasonically disperse at 300W power for 15 min, then filter, and dry in an 80℃ oven for 1 h to coat the surface of silicon carbide with coupling agent molecules;

[0128] Step 2: Pour 100 parts of epoxy gel coat resin into a mixing tank, preheat in a 40°C water bath for 10 minutes, and stir at 500 rpm. Add the coupling agent-modified montmorillonite to the epoxy gel coat resin, increase the stirring speed to 1500 rpm, and shear and disperse for 20 minutes. Add 10 parts of pretreated silicon carbide micro powder, continue stirring and shearing at 1500 rpm for 15 minutes, then add 6 parts of polyurethane microspheres, reduce the speed to 1000 rpm, and stir for 10 minutes.

[0129] Step 3: Add 0.2 parts of polyether modified silane leveling agent and 0.1 parts of organosilicon defoamer to the mixture, and stir at 800 rpm for 5 minutes to ensure uniform dispersion of the additives.

[0130] Step 4: Mix the epoxy gel coat resin and T31 modified curing agent at a weight ratio of 100:15, and stir at 500 rpm for 3 minutes to obtain the modified epoxy gel coat.

[0131] S250. After the epoxy gel coat surface has dried, mix the epoxy resin, curing agent, and toughening agent according to the ratio. Use a scraper and brush to apply the mixture to the positive mold. First, lay a layer of 0.2mm fiberglass cloth, then apply a layer of the mixed epoxy resin. Then, lay a layer of 0.4mm fiberglass cloth and apply a layer of the mixed epoxy resin. Achieve the required thickness for the negative mold according to the size requirements. After the negative mold is pasted, it will cure.

[0132] The epoxy resin undergoes modification treatment, and the preparation steps are as follows:

[0133] Step 1: Add 5 parts of nano silica to 2 parts of KH-560 coupling agent dissolved in 10 parts of anhydrous ethanol, stir at 400 rpm for 30 min in a 60℃ water bath to allow the ethoxy-OC2H5 of the coupling agent to react with the hydroxyl-OH on the surface of the nano silica, dry in an 80℃ oven for 2 h to remove ethanol, and obtain KH-560 modified nano silica.

[0134] Step 2: Heat 100 parts of epoxy resin to 60°C, add 8 parts of carboxyl liquid nitrile rubber, stir at 800 rpm for 20 minutes, then heat to 80°C and stir for 30 minutes to obtain epoxy resin-carboxyl liquid nitrile rubber system.

[0135] Step 3: Add the modified nano-silica to the epoxy resin-carboxylated liquid nitrile rubber system, increase the rotation speed to 1500 rpm, shear and disperse for 20 min, add 2 parts of KH-560 coupling agent, reduce the rotation speed to 800 rpm and stir for 10 min.

[0136] Step 4: Add 5 parts of benzyl glycidyl ether reactive diluent, stir for 10 minutes and adjust the viscosity to 5000 mPa·s. Mix the epoxy resin and T31 modified amine curing agent at a weight ratio of 100:15 and stir at 500 rpm for 3 minutes to complete the modification of the epoxy resin.

[0137] S260. After the female mold has cured for the time specified in step five, punch holes in the female mold and use an air pump to pressurize and demold the female mold onto the male mold. Then, measure the female mold again according to the size requirements of the female mold.

[0138] S270. After demolding, the surface of the female mold is treated with 240-grit wet sandpaper, and then treated with 400-grit wet sandpaper to smooth the female mold.

[0139] In this embodiment, fiberglass cloth is used in the shell mold making process. Fiberglass woven fabric is a plain weave fabric made of untwisted roving. Fiberglass cloth is mostly used in hand lay-up processes. Fiberglass cloth is made by drawing glass into extremely fine glass fibers, which at this point have excellent flexibility. The glass fibers are spun into yarn, and then woven into fiberglass cloth using a loom.

[0140] The modified epoxy resin exhibits high wettability to carbon fibers. Combined with the surface protection of the gel coat, this enhances the interlaminar shear strength of the carbon fiber composite material, resulting in more stable overall mechanical properties. The abrasion-resistant protection of the modified epoxy gel coat reduces direct water erosion of the carbon fibers, extending the shell's service life. As a surface coating for the mold, the modified epoxy gel coat's smooth surface, in conjunction with the release agent, ensures high surface precision after demolding. The gel coat's abrasion resistance also reduces the mold's wear rate, extending its lifespan. The high interfacial bonding force between the modified epoxy resin and the modified epoxy gel coat strengthens the bond between the metal embedded parts, the carbon fiber matrix, and the epoxy gel coat protective layer, increasing pull-out force and preventing the embedded parts from loosening or falling off in underwater conditions.

[0141] The other components and connections are the same as in Specific Implementation Method 3.

[0142] Specific Implementation Method Six: Combination Figures 1 to 15 This embodiment describes step three (S300) of fabricating the housing, which includes the following steps:

[0143] S310. Cut carbon fiber cloth and vacuum bags according to the size of the female mold;

[0144] S320: Apply release wax to the surface of the female mold, and polish it with a cotton cloth after 10-20 minutes; repeat S320 three times.

[0145] S330 After the release wax process is completed, apply release agent to the surface of the female mold. After the release agent has dried, apply a second release agent.

[0146] S340. After the release agent surface is air-dried, mix the epoxy gel coat according to the ratio, and use a scraper to apply the epoxy gel coat to the female mold for the first time. After the epoxy gel coat surface is air-dried, apply the epoxy gel coat for the second time.

[0147] S350. After the epoxy gel coat surface has dried, mix epoxy resin, curing agent and toughening agent according to the ratio. Use a scraper and brush to apply it to the negative mold. First, lay a layer of 0.2mm carbon fiber cloth, then scrape and apply a layer of mixed epoxy resin. Then lay a layer of 0.4mm carbon fiber cloth, then scrape and apply a layer of mixed epoxy resin. The thickness of the shell is achieved according to the shell size.

[0148] Then, first lay a layer of release cloth on the surface of the pasted carbon fiber cloth, then lay a layer of absorbent cotton, seal the female mold with vacuum bags and sealing strips, leave an air vent, and use a vacuum pump to vacuum-press and solidify the female mold.

[0149] S360. After curing, drill holes in the female mold, use an air pump to pressurize and demold the shell, and use an angle grinder to cut off the excess part of the shell according to the size requirements.

[0150] S370. Finally, the surface of the casing is treated with 240-grit sandpaper and wet sanding.

[0151] In this embodiment, the carbon fiber non-pressure resistant shell is manufactured using a vacuum bag pressing process. Vacuum bag pressing refers to a method in which the part is placed inside a vacuum bag and cured under vacuum pressure by drawing a vacuum. The vacuum bag is made of a high-strength, highly ductile material such as nylon film, and is bonded to the mold with an adhesive sealing strip. The part attached to the mold is then wrapped inside the bag, which contains a gas-guiding felt to ensure unobstructed vacuum pathways. The bag is equipped with a vacuum nozzle that can be connected to a vacuum pump via a conduit.

[0152] The other components and connections are the same as in Specific Implementation Method 3.

[0153] Specific implementation method seven: Combining Figures 1 to 15 This embodiment describes step four (S400) of creating the skeleton, which includes the following steps:

[0154] S410. Process carbon fiber sheets for the skeleton using vacuum bag compression molding process according to the skeleton size.

[0155] S420: Arrange multiple skeleton components into a single carbon fiber sheet, and then use a carving machine to process the carbon fiber sheet into multiple skeleton components.

[0156] S430, Finally, assemble the processed carbon fiber plate skeleton components into a skeleton, and then grind them.

[0157] In this embodiment, the carbon fiber skeleton is manufactured using a vacuum bag compression molding process. Vacuum bag molding refers to a method in which the part is placed inside a vacuum bag and cured under vacuum pressure by drawing a vacuum. The vacuum bag is made of a high-strength, ductile material and is bonded to the mold with an adhesive sealing strip. The part attached to the mold is wrapped inside the bag, and a gas-guiding felt is placed inside the bag to ensure unobstructed vacuum passages. The bag is equipped with a vacuum nozzle that can be connected to a vacuum pump via a conduit.

[0158] The other components and connections are the same as in Specific Implementation Method 3.

[0159] Specific implementation method eight: Combination Figures 1 to 15 This embodiment describes a process in which the ambient temperature is maintained at 21°C throughout the entire process of manufacturing the male mold and the female mold of the housing. 。 C-28 。 C.

[0160] In a preferred embodiment, the humidity range is maintained between 40% and 60% throughout the entire process of manufacturing the male mold and the female mold for the housing.

[0161] In a preferred embodiment, after the fifth step of making the shell female mold is completed, the curing time is more than 24 hours.

[0162] In a preferred embodiment, step five of the shell fabrication process involves using a vacuum pump to vacuum bag press-fit the female mold, with the vacuum bag pressing and holding time ranging from 3 to 5 hours and the curing time exceeding 24 hours.

[0163] The other components and connections are the same as in Specific Implementation Method 3.

[0164] Specific Implementation Method Nine: Combining Figures 1 to 15 In this embodiment, after the female mold is pasted in step five of making the shell mold, the curing time is 24-48 hours; in step five of making the shell, the female mold is vacuum bagged and molded using a vacuum pump, the vacuum bag pressing time is 3-10 hours, and the curing time is 24-48 hours.

[0165] In a preferred embodiment, after the female mold is pasted in step five of making the shell mold, the curing time is 24 hours; in step five of making the shell, the female mold is vacuum bagged and molded using a vacuum pump, the vacuum bag is pressed for 3 hours, and the curing time is 24 hours.

[0166] In a preferred embodiment, after the female mold is pasted in step five of making the shell mold, the curing time is 48 hours; in step five of making the shell, the female mold is vacuum bagged and molded using a vacuum pump, the vacuum bag is pressed for 10 hours, and the curing time is 48 hours.

[0167] The other components and connections are the same as in Specific Implementation Method 3.

[0168] Specific Implementation Method Ten: Combining Figures 1 to 15 This embodiment describes a method for processing the non-pressure hull of an unmanned underwater vehicle. The method involves processing the main structure of the non-pressure hull of the vehicle, maintaining an ambient temperature of 21-28°C and a humidity range of 40%-60% throughout the entire process of manufacturing the male and female molds of the hull. The method includes the following steps:

[0169] Step 1: Making the male mold for the shell:

[0170] 1. Using 20mm as a reference, lay out the engraving machine software drawings from head to tail in sequence for the shell drawing;

[0171] 2. Input the layout drawings into the engraving machine, and process the 20mm thick PVC foam board according to the drawings;

[0172] 3. After processing, the PVC foam boards are glued and fixed together in sequence with 502 glue according to the drawings to form a preliminary positive mold;

[0173] 4. Use a sander and sandpaper of 80 grit, 240 grit and 400 grit to sand the bonded positive mold according to the drawing requirements. Then measure the positive mold again according to the drawing.

[0174] 5. Mix the body filler according to the ratio, and use a scraper to apply the body filler to the entire surface of the positive mold, filling the pits, holes and uneven areas on the surface of the positive mold.

[0175] 6. Use a sander and wet sandpaper of 80 grit, 240 grit and 400 grit to treat the applied putty layer in sequence;

[0176] 7. Spray paint the treated male mold with epoxy primer;

[0177] 8. After painting, the positive mold should be sanded with 240-grit and 400-grit sandpaper in sequence.

[0178] Step 2: Making the shell female mold:

[0179] 1. Cut the fiberglass cloth according to the size of the positive mold and the thickness of the mold. The fiberglass cloth is available in two thicknesses: 0.2mm and 0.4mm.

[0180] 2. Apply release wax to the surface of the male mold, wait 10 minutes, then polish the release wax layer with a cotton cloth; repeat the above steps three times.

[0181] 3. After the release wax process is completed, apply release agent to the positive mold. After the release agent surface is no longer sticky, apply a second release agent.

[0182] 4. After the release agent has dried, mix the epoxy gel coat according to the ratio, and use a scraper to apply the epoxy gel coat to the male mold for the first time. When the epoxy gel coat is no longer sticky to the touch, apply the epoxy gel coat for the second time.

[0183] 5. After the epoxy gel coat is no longer sticky, mix the epoxy resin, hardener and toughening agent according to the ratio, and apply it to the mold with a scraper and brush. First, lay a layer of 0.2mm glass fiber cloth that has been cut, and then apply a layer of mixed epoxy resin. Only one layer of 0.2mm glass fiber cloth is needed.

[0184] Then, lay down a layer of 0.4mm cut fiberglass cloth, and then apply a layer of mixed epoxy resin; achieve the required thickness of the negative mold; after the negative mold is pasted, cure for more than 24 hours.

[0185] 6. After the female mold has cured for the specified time, holes are drilled in the female mold, and the mold is demolded by applying pressure with an air pump. The female mold is then re-measured according to the drawings.

[0186] 7. After demolding, treat the surface of the female mold with 240-grit wet sandpaper, and then with 400-grit wet sandpaper to make the mold surface smooth.

[0187] Step 3: Shell Fabrication

[0188] 1. Cut carbon fiber cloth and vacuum bags according to the size of the negative mold. The carbon fiber cloth is available in two thicknesses: 0.2mm and 0.4mm. The vacuum bag should be cut to a size that is a certain amount larger than the mold.

[0189] 2. Apply release wax to the surface of the female mold, wait 10 minutes, then polish with a cotton cloth; repeat the above steps three times.

[0190] 3. After the release wax process is completed, apply release agent to the female mold. After the release agent surface is no longer sticky, apply a second release agent.

[0191] 4. After the release agent has dried, mix the epoxy gel coat according to the ratio, and apply the epoxy gel coat to the mold for the first time with a scraper. When the epoxy gel coat is no longer sticky to the touch, apply the epoxy gel coat for the second time.

[0192] 5. After the epoxy gel coat is no longer sticky, mix the epoxy resin, curing agent and toughening agent according to the ratio; use a scraper and brush to apply it to the mold. First, lay a layer of 0.2mm carbon fiber cloth that has been cut, and then scrape a layer of mixed epoxy resin. Only one layer of 0.2mm carbon fiber cloth is needed.

[0193] Then, lay a layer of 0.4mm carbon fiber cloth, followed by a layer of mixed epoxy resin, to achieve the required mold thickness. Finally, lay a release cloth on the surface of the carbon fiber cloth, followed by a layer of absorbent cotton. Seal the female mold with a vacuum bag and sealing strip, leaving an air vent. Use a vacuum pump to evacuate the female mold and perform vacuum bag pressing. Vacuum pressing lasts for 3-5 hours, followed by curing for at least 24 hours.

[0194] 6. After curing, drill holes in the female mold, use an air pump to pressurize and demold the shell, and cut off the excess part of the shell with an angle grinder according to the drawing requirements;

[0195] 7. The surface of the shell product is treated with 240-grit sandpaper and wet sanding, and the shell is then machined to form the finished product.

[0196] Step 4: Skeleton Construction

[0197] 1. Process carbon fiber sheets using vacuum bag compression molding process according to the dimensions in the drawings. The skeleton is a flat structure. The negative mold used for vacuum bag compression molding does not require special processing. Arrange multiple skeleton components into a whole carbon fiber sheet.

[0198] 2. Based on the drawings, use a CNC engraving machine to process the carbon fiber sheet into multiple skeleton components;

[0199] 3. According to the drawings, assemble the processed carbon fiber plate skeleton components into a skeleton, and then grind and process them.

[0200] Step 5: Assembly of the shell and frame:

[0201] 1. Assemble the shell and frame according to the drawing requirements and check the dimensions. Cut the carbon fiber cloth, bond the whole assembly and strengthen the bonding of the embedded parts.

[0202] 2. The shell and frame are treated as a whole, and sanded with 240-grit sandpaper.

[0203] 3. Spray epoxy primer onto the sanded non-pressure resistant shell main structure, cure for more than 8 hours, and then sand with 240-grit sandpaper. Repeat the above steps twice.

[0204] 4. Apply topcoat to the non-pressure-resistant main structure of the shell after sanding the epoxy primer.

[0205] Workshop environment: Before mold manufacturing, dust removal and cleaning of the manufacturing area should be carried out;

[0206] Raw material selection: Select suitable raw materials and resins according to the requirements of the shell product manufacturing;

[0207] Tools and raw material preparation: Tools include a flat engraving machine, industrial vacuum cleaner, air pump, vacuum pump, angle grinder cutting discs and grinding discs, electronic scale, and grinder; for making molds and shell product platforms, electric drill, drill bits, scraper, tape measure, calipers, right angle ruler, height gauge, ruler, board brush, glue basin, release wax, release agent, release cloth, glue absorbent, sandpaper of 80 grit, 240 grit and 400 grit, spray gun, epoxy primer, epoxy topcoat, carbon fiber cloth in 0.2mm and 0.4mm thicknesses, fiberglass cloth in 0.2mm and 0.4mm thicknesses, epoxy resin, curing agent, toughening agent, and 20mm thick PVC foam board.

[0208] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A non-pressure-resistant hull main structure for an unmanned underwater vehicle, characterized in that: It includes a lower shell (2) and a frame (3), the lower shell (2) and the frame (3) are fixedly connected, the frame (3) includes a longitudinal frame (31) and a transverse frame (32); metal embedded parts (6) are provided on both the longitudinal frame (31) and the transverse frame (32); the materials of the lower shell (2) and the frame (3) are both carbon fiber composite materials; The longitudinal frame (31) is provided with a first snap-fit ​​(36), and the transverse frame (32) is provided with a second snap-fit ​​(37). The first snap-fit ​​(36) and the second snap-fit ​​(37) are engaged and fitted together. The longitudinal frame (31) and the transverse frame (32) are arranged perpendicularly to each other and are bonded together. A transverse rib (33) is also provided between the transverse skeletons (32), a longitudinal skeleton slot (34) is provided on the longitudinal skeleton (31), and a rib plate block (35) is provided on the transverse rib (33). The longitudinal skeleton slot (34) and the rib plate block (35) are engaged and matched. The longitudinal skeleton (31) and the transverse rib (33) are arranged perpendicular to each other and are bonded together. Multiple sets of frame angle irons (10) are provided around the connection point of the longitudinal frame (31) and the transverse frame (32). The frame angle irons (10) are connected to the longitudinal frame (31) and the transverse frame (32) by frame bolts (9). Each set of frame angle irons (10) includes four frame angle irons (10), which are respectively set at the four corners of the connection point of the frame (3).

2. The non-pressure-resistant hull main structure of the unmanned underwater vehicle according to claim 1, characterized in that: The transverse frame (32) is installed at the bow and stern of the aircraft, and the transverse frame (32) divides the aircraft cabin formed by the non-pressure hull main structure into the bow section, the midship section and the stern section. A spreader seat (7) is provided on the top of the transverse frame (32) at the bow and stern respectively. A third bayonet (38) is provided on the transverse frame (32), and a spreader seat bayonet (71) is provided on the spreader seat (7). The third bayonet (38) and the spreader seat bayonet (71) are engaged. The spreader seat (7) is fixed to the transverse frame (32) around its perimeter by spreader seat angle iron (8).

3. The non-pressure-resistant hull main structure of the unmanned underwater vehicle according to claim 1, characterized in that: The metal embedded part (6) has a top-bottom circular structure and includes a square embedded part (61) and a circular embedded part (62). The circular embedded part (62) is provided with a connecting hole (63), and the skeleton (3) is provided with a corresponding top-bottom circular embedded hole. The metal embedded part (6) is installed in the embedded hole and fixedly connected to the skeleton (3).

4. A method for processing a non-pressure-resistant hull of an unmanned underwater vehicle, used for processing the main structure of the non-pressure-resistant hull as described in any one of claims 1-3, characterized in that: Includes the following steps: Step 1 S100: Make the male mold of the shell; Step 2 S200: Make the female mold of the shell; Step 3 S300: Make the shell; Step 4 S400: Make the skeleton; Step 5 S500: Assemble the shell and frame into a non-pressure-resistant shell main structure, including the following steps: S510. Cut carbon fiber cloth according to the size parameters of the shell and frame, then bond and assemble the shell and frame and set the embedded parts to assemble the main shell structure. S520. Grinding of the main shell structure: Use 240-grit sandpaper to grind the shell and frame of the main shell structure as a whole. S530: Spray epoxy primer onto the sanded main structure of the shell, cure for 8-24 hours, and then sand with 240-grit sandpaper; repeat step S530 twice. S540. Apply topcoat to the sanded main structure of the shell.

5. The method for processing the non-pressure-resistant hull of an unmanned underwater vehicle according to claim 4, characterized in that: Step one, S100, involves fabricating the male mold for the shell, and includes the following steps: S110. Based on the shell dimensions of 20mm, arrange the engraving machine drawings from head to tail in sequence. S120. Input the layout drawing into the engraving machine and process the 20mm PVC foam board in sequence; S130. The processed PVC foam boards are glued together in sequence to form a positive mold. S140. Use a grinder and 80-grit, 240-grit, and 400-grit sandpaper to grind the bonded positive mold in sequence, and re-measure the positive mold according to the size requirements. S150 mixed body filler is applied to the entire surface of the positive mold by scraping and coating with body filler. S160. Use a sander and 80-grit, 240-grit, and 400-grit sandpaper to sand the putty in sequence. S170. Spray epoxy primer onto the positive mold after it has been sanded and coated with putty. S180. After painting, the positive mold is polished with 240-grit and 400-grit sandpaper in sequence.

6. The method for processing the non-pressure-resistant hull of an unmanned underwater vehicle according to claim 4, characterized in that: Step two, S200, involves creating the shell female mold, including the following steps: S210. Cut fiberglass cloth according to the size of the positive mold and the thickness of the negative mold. S220. Apply release wax to the surface of the male mold and polish it with a cotton cloth after 10-20 minutes; repeat step S220 three times. S230 After the release wax process is completed, apply release agent to the surface of the male mold. After the release agent has dried, apply a second release agent. S240. After the release agent surface is air-dried, mix the epoxy gel coat and apply the epoxy gel coat to the male mold for the first time. After the epoxy gel coat surface is air-dried, apply the epoxy gel coat for the second time. The epoxy gel coat undergoes modification treatment, and the preparation steps are as follows: Step 1: Take 3 parts of nano-montmorillonite, add 0.5 parts of KH-560 coupling agent dissolved in 10 parts of anhydrous ethanol, stir at 300 rpm for 30 min in a 50℃ water bath to allow the ethoxy-OC2H5 of the coupling agent to react with the hydroxyl-OH on the surface of montmorillonite; then dry in an 80℃ oven for 2 h to remove ethanol and obtain coupling agent modified montmorillonite; take 10 parts of silicon carbide micro powder, add 1.5 parts of KH-560 coupling agent dissolved in 20 parts of anhydrous ethanol, ultrasonically disperse at 300W power for 15 min, then filter, and dry in an 80℃ oven for 1 h to coat the surface of silicon carbide with coupling agent molecules; Step 2: Pour 100 parts of epoxy gel coat resin into a mixing tank, preheat in a 40°C water bath for 10 minutes, and stir at 500 rpm. Add the coupling agent-modified montmorillonite to the epoxy gel coat resin, increase the stirring speed to 1500 rpm, and shear and disperse for 20 minutes. Add 10 parts of pretreated silicon carbide micro powder, continue stirring and shearing at 1500 rpm for 15 minutes, then add 6 parts of polyurethane microspheres, reduce the speed to 1000 rpm, and stir for 10 minutes. Step 3: Add 0.2 parts of polyether modified silane leveling agent and 0.1 parts of organosilicon defoamer to the mixture, and stir at 800 rpm for 5 minutes to ensure uniform dispersion of the additives. Step 4: Mix epoxy gel coat resin and T31 modified curing agent at a weight ratio of 100:15, and stir at 500 rpm for 3 minutes to obtain the modified epoxy gel coat. S250. After the epoxy gel coat surface has dried, mix epoxy resin, curing agent and toughening agent; first lay a 0.2mm glass fiber cloth, then scrape a layer of mixed epoxy resin; then lay a 0.4mm glass fiber cloth and scrape a layer of mixed epoxy resin in sequence; achieve the thickness of the female mold according to the size requirements of the female mold, and cure after the female mold is pasted; The epoxy resin undergoes modification treatment, and the preparation steps are as follows: Step 1: Add 5 parts of nano silica to 2 parts of KH-560 coupling agent dissolved in 10 parts of anhydrous ethanol, stir at 400 rpm for 30 min in a 60℃ water bath to allow the ethoxy-OC2H5 of the coupling agent to react with the hydroxyl-OH on the surface of the nano silica, dry in an 80℃ oven for 2 h to remove ethanol, and obtain KH-560 modified nano silica. Step 2: Heat 100 parts of epoxy resin to 60°C, add 8 parts of carboxyl liquid nitrile rubber, stir at 800 rpm for 20 minutes, then heat to 80°C and stir for 30 minutes to obtain epoxy resin-carboxyl liquid nitrile rubber system. Step 3: Add the modified nano-silica to the epoxy resin-carboxylated liquid nitrile rubber system, increase the rotation speed to 1500 rpm, shear and disperse for 20 min, add 2 parts of KH-560 coupling agent, reduce the rotation speed to 800 rpm and stir for 10 min. Step 4: Add 5 parts of benzyl glycidyl ether reactive diluent, stir for 10 minutes and adjust the viscosity to 5000 mPa·s. Mix the epoxy resin and T31 modified amine curing agent at a weight ratio of 100:15 and stir at 500 rpm for 3 minutes to obtain the modified epoxy resin. S260. After the female mold has cured for the time specified in step five, punch holes in the female mold and use an air pump to pressurize and demold the female mold from the male mold. Then, measure the female mold again according to the size requirements. S270. After demolding, the surface of the female mold is treated with 240-grit wet sandpaper, and then treated with 400-grit wet sandpaper.

7. The method for processing the non-pressure-resistant hull of an unmanned underwater vehicle according to claim 4, characterized in that: Step three, S300, involves fabricating the housing, including the following steps: S310. Cut carbon fiber cloth and vacuum bags according to the size of the female mold; S320. Apply release wax to the surface of the female mold and polish it with a cotton cloth after 10-20 minutes; repeat step S320 three times. S330 After the release wax process is completed, apply release agent to the surface of the female mold. After the release agent has dried, apply a second release agent. S340. After the release agent surface is air-dried, mix the epoxy gel coat and apply the epoxy gel coat to the female mold for the first time. After the epoxy gel coat surface is air-dried, apply the epoxy gel coat for the second time. S350. After the epoxy gel coat surface has dried, mix epoxy resin, curing agent and toughening agent. First, lay a 0.2mm carbon fiber cloth, then scrape a layer of mixed epoxy resin. Then lay a 0.4mm carbon fiber cloth, then scrape a layer of mixed epoxy resin, to achieve the shell thickness according to the shell size. Then, first lay a layer of release cloth on the surface of the pasted carbon fiber cloth, then lay a layer of absorbent cotton, seal the female mold with vacuum bags and sealing strips, leave an air vent, and use a vacuum pump to vacuum-press and solidify the female mold. S360. After curing, drill holes in the female mold, use an air pump to pressurize and demold the shell, and cut the excess part of the shell according to the size requirements using an angle grinder. S370. Finally, the surface of the casing is treated with 240-grit sandpaper and wet sanding.

8. The method for processing the non-pressure-resistant hull of an unmanned underwater vehicle according to claim 4, characterized in that: Step four, S400, involves fabricating the skeleton, including the following steps: S410. Process carbon fiber sheets for the skeleton using vacuum bag compression molding process according to the skeleton size. S420: Arrange multiple skeleton components into a single carbon fiber sheet, and then use a carving machine to process the carbon fiber sheet into multiple skeleton components. S430, Finally, assemble the processed carbon fiber plate skeleton components into a skeleton, and then grind them.

9. The method for processing the non-pressure-resistant hull of an unmanned underwater vehicle according to claim 7, characterized in that: In step S250 of making the shell female mold, the mold is cured after the paste is applied, and the curing time is 24-48 hours.

10. The method for processing the non-pressure-resistant hull of an unmanned underwater vehicle according to claim 8, characterized in that: In step S350 of the shell fabrication, a vacuum pump is used to vacuum bag press the female mold, with the vacuum bag pressing time ranging from 3 to 10 hours and the curing time from 24 to 48 hours.

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