A composite material reinforced pressure-resistant shell core mold design and shell integral molding method

Abstract

A composite material reinforced pressure shell mandrel design and integrated shell molding method are disclosed, belonging to the field of submersible pressure shells. The method includes the following steps: mandrel material selection; mandrel structure design; the mandrel is assembled from multiple arc-shaped segments arranged sequentially along the circumference, each segment consisting of multiple preferred and multiple non-preferred arc-shaped segments, alternating circumferentially, with the deflection angle between the contact surfaces of the preferred and non-preferred segments being 30°–45°; the mandrel is assembled sequentially from one end to the other on the outer circumference of a steel shaft; integrated molding of the reinforced pressure shell; yarn is wound into the annular space between each pair of adjacent mandrels to match the outer contour of the reinforcing rib with that of the mandrel; then, a skin is wound around the outer circumference of the reinforcing rib and the mandrel, and cured; the mandrel is demolded. The assembly and demolding methods of this invention are simple and easy to operate.

Description

Technical Field

[0001] This invention belongs to the field of submersible pressure hulls, specifically relating to a composite material reinforced pressure hull core mold design and an integral molding method for the hull. Background Technology

[0002] Fiber-reinforced composite materials possess excellent properties such as high specific strength, high specific stiffness, good corrosion resistance, and strong design flexibility, and are gradually being widely used in the field of marine engineering. In recent years, underwater vehicles have developed rapidly, and the pressure hull, as the core of the structure, is increasingly being made of fiber-reinforced composite materials to achieve weight reduction under load conditions, thereby increasing effective payload and improving endurance.

[0003] In shallow sea areas, a common problem faced by pressure hulls is insufficient stability. While increasing wall thickness can solve this problem, it also results in an extremely high safety factor for strength, leading to a significant increase in weight and cost, which is counterproductive. Reinforcement, as a common method to improve the stability of pressure hulls, can control the utilization rate of material properties and the increase in weight and cost as much as possible.

[0004] Pressure shell molding mainly includes two methods: prepreg laying and yarn winding. Compared with cylindrical shells of equal wall thickness, stiffened shell molding is more complex. Since composite materials are not suitable for machining, they can usually only be prepared by staged curing (curing the reinforcing ribs first and then laying the skin for curing). This molding method has shortcomings in the bonding between the ribs and the skin (laying the skin on the cured ribs cannot completely guarantee that the circumferential section of the ribs is perpendicular to the skin). In addition, some one-piece molded pressure shell core molds use steel core molds, which are not only heavy, but also have a more complex logical sequence for assembly and demolding, making the process more complicated and difficult to operate (for core mold designers, strict calculation and simulation are required to ensure the accuracy of the core mold segment structure dimensions; and for the manufacturing staff, a certain amount of time is also required to master the process). Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the background art by providing a composite material reinforced pressure-resistant shell core mold design and a shell integral molding method.

[0006] This invention uses an integral molding process to prepare the shell. After the ribs are wound, the fibers are in a variable state (because they are not cured) when the skin is wound, which allows the ribs to fit better with the core mold. Meanwhile, the resin is in a fluid state, which can effectively fill the gaps in some joints where there are many or large pores.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A composite material reinforced pressure-resistant shell core mold design and a method for integrally molding the shell, the method comprising the following steps:

[0009] Step 1: Selection of core mold material; Foam or plastic is used as the core mold material;

[0010] Step 2, core mold structure design; The core mold is assembled by arranging multiple arc-shaped segments sequentially along the circumference. The multiple arc-shaped segments consist of multiple preferred arc-shaped segments and multiple non-preferred arc-shaped segments. The multiple preferred arc-shaped segments and multiple non-preferred arc-shaped segments are arranged alternately along the circumference. The contact surfaces between the preferred arc-shaped segments and the non-preferred arc-shaped segments are all inclined surfaces. The deflection angle α of the inclined surface of the preferred arc-shaped segments is 30°-45°.

[0011] Step 3: Mandrel Assembly; Assemble multiple mandrels sequentially from one end to the other on the outer surface of the steel shaft. Specifically: First, assemble the first mandrel on the outer surface of one end of the steel shaft. The first mandrel is bonded to the steel shaft. Then, clamp a positioning block with the same width as the rib to be wound onto the outer surface of the steel shaft. This positioning block is set close to the first mandrel. Next, assemble the second mandrel on the outer surface of the steel shaft. The second mandrel is set close to the positioning block and bonded to the steel shaft. Then, remove the positioning block between the first and second mandrels. Next, clamp and fix a positioning block with the same width as the rib to be wound onto the outer surface of the steel shaft. This positioning block is set close to the second mandrel. Next, assemble the third mandrel on the outer surface of the steel shaft. The third mandrel is set close to the positioning block and bonded to the steel shaft. Then, remove the positioning block between the second and third mandrels. Continue in this manner until the last mandrel is assembled and bonded to the steel shaft. Finally, remove the positioning block adjacent to the last mandrel.

[0012] Step 4: Integral molding of reinforced pressure-resistant shell; Yarn is wound in the annular space between each pair of adjacent core molds. When the yarn is wound to be roughly the same as the outer diameter of the core mold, a rib is formed. The outer diameter of the rib is adjusted so that the outer contour of the rib matches the outer contour of the core mold. Then, a skin is wound on the outer circumference of the rib and the core mold. When the wound skin reaches the designed thickness, it is cured and molded to produce a reinforced pressure-resistant shell molded body.

[0013] Step 5: Core mold demolding; First, pull out the steel shaft of the reinforced pressure shell molding body, and then remove all the arc surface segments of the core mold to make a composite material reinforced pressure shell; The disassembly sequence of all the arc surface segments of the core mold is: first disassemble the priority arc surface segments, and then disassemble the non-priority arc surface segments.

[0014] Furthermore, in step one, the plastic is one of polytetrafluoroethylene, nylon, polyoxymethylene, PVC, or a combination of at least two materials; the foam is one of PMI foam, high-strength polyurethane foam, polystyrene foam, acrylate foam, polyvinyl chloride foam, or a combination of at least two materials.

[0015] Furthermore, in step two, the number of segments on the multiple arc surfaces of the core mold is 6, 8, or 10.

[0016] Compared with the prior art, the beneficial effects of the present invention are: the method of the present invention has a wide range of applications. It can not only prepare unidirectional rib pressure shells such as ring ribs and longitudinal ribs (the longitudinal ribs refer to ribs with angles other than 90° ring ribs, with a ply angle of less than 90°, and a ply tooling is required at the end of the steel shaft during specific laying, which is already available in the field of composite material winding), but also prepare more complex grid ribs with different angles (similar to...). Figure 15 The core mold is a pressure-resistant shell with a specific shape. In selecting the core mold material, this invention focuses on lightweight materials with high hardness and machinability. These materials are advantageous because they are easy to operate and not easily limited by workspace. Further considerations include curing temperature (different materials have different curing temperatures, which is the current process), frequency of use (i.e., the number of pressure-resistant shells prepared, which determines the number of times the core mold is used and the time interval between uses; the core mold needs to maintain structural stability within the number of uses to prevent significant deformation due to repeated winding and demolding), etc., to select a suitable core mold material. The method of this invention is easy to master, the preparation process is short, and the assembly and demolding logic using this method is simple and easy to understand, reducing the workload of design and preparation personnel. Attached Figure Description

[0017] Figure 1 This is a front sectional view of a composite material reinforced pressure shell prepared using the method of the present invention;

[0018] Figure 2 This is an isometric view of a composite material ring-ribbed pressure-resistant shell prepared using the method of the present invention;

[0019] Figure 3 This is a schematic diagram of the core mold assembly;

[0020] Figure 4 It is an isometric drawing of the mandrel;

[0021] Figure 5 This is a schematic diagram of the cross-section of the core mold;

[0022] Figure 6 A schematic diagram showing the deflection angle α of the contact surface of the preferred arc-shaped segment;

[0023] Figure 7 This is a force diagram of the core mold; in the diagram: F represents the tensile force when removing the core mold; N represents the resistance of the non-priority arc surface segmentation; f represents the frictional force, i.e., resistance, when removing the core mold;

[0024] Figure 8 The preferred option is the isometric drawing of the arc-shaped surface with segments.

[0025] Figure 9 The preferred option is the front view of the arc-shaped surface divided into segments;

[0026] Figure 10 Is it a non-priority option for the isometric projection of a segmented arc surface?

[0027] Figure 11 Is it a non-priority item for the lobed front view of the arc surface?

[0028] Figure 12 It is an isometric drawing of a tooling used for demolding with a spiral-shaped feed mechanism;

[0029] Figure 13 This is a schematic diagram of laying pre-embedded tape on the surface of the core mold;

[0030] Figure 14 It is an isometric view of the core mold surface with pre-embedded tape laid on it;

[0031] Figure 15 This is a schematic diagram of a mesh-reinforced pressure shell;

[0032] Figure 16 This is a side view of a mesh-reinforced pressure shell;

[0033] Figure 17 It is an isometric view of drilling threaded holes on the arc-shaped segments of the mandrel.

[0034] Figure 18 It is an isometric view of a bolt being screwed into a threaded hole on the arc-shaped segment of the mandrel.

[0035] Figure 19 It is an isometric drawing of the segmented arc surface of the mandrel, which uses auxiliary tools to connect bolts to the mandrel.

[0036] The component names and reference numerals in the above figures are as follows:

[0037] 1. Skin, 2. Ring rib, 3. Steel shaft, 4. Preferred arc surface segmentation, 5. Non-preferred arc surface segmentation, 6. Spiral screw-in tooling, 7. Embedded tape, 8. Mesh rib, 9. Bolt, 10. Auxiliary tools, 11. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] Specific Implementation Method 1: This implementation method discloses a composite material reinforced pressure-resistant shell core mold design and a method for integrally molding the shell, the method including the following steps:

[0040] Step 1: Material selection for core mold 4; Foam or plastic is used as the material for core mold 4;

[0041] Step 2, Core Mold 4 Structure Design; Core Mold 4 is assembled from multiple arc-shaped segments arranged sequentially along the circumference. These arc-shaped segments consist of multiple preferred arc-shaped segments 5 and multiple non-preferred arc-shaped segments 6. The preferred and non-preferred arc-shaped segments 5 and 6 are alternately arranged along the circumference. The contact surfaces between the preferred and non-preferred arc-shaped segments 5 and 6 are all inclined surfaces. The deflection angle α of the inclined surface of the preferred arc-shaped segment 5 is 30°-45° (e.g., ...). Figures 1-11 (as shown);

[0042] Different reinforced pressure shells correspond to different core mold structures. Note: For reinforcement schemes with unequal spacing, only the axial width needs to be changed. This method can be used not only to prepare traditional rectangular section reinforcements, but also trapezoidal section reinforcements, "T"-shaped section reinforcements, etc. (not limited to these types of sections).

[0043] The core of the core mold 4 structure design lies in determining the segmentation scheme, which mainly includes the number of segments and the structural dimensions of the segments.

[0044] Regarding the number of segments: On the one hand, ease of operation requires a slightly larger number of segments, as a slightly larger number results in smaller individual segments, making them easier for operators to handle (subsequently requiring the covering with adhesive release cloth). On the other hand, ensuring the precision of core mold 4 assembly requires a slightly smaller number of segments. Each segment has varying degrees of error in machining and subsequent assembly, which affects the precision of core mold 4 after assembly, thus impacting the forming precision of the ribs. Therefore, fewer segments have a smaller impact. In summary, it is recommended that the number of segments be 6 or 8 (not less than 6, but slightly more than 8 is permissible in special cases, such as when the circumferential dimension of core mold 4 is large after assembly).

[0045] Regarding the segmented structural design, the aim is to facilitate subsequent demolding of the core mold 4 after curing. The key lies in the contact surfaces between different segments, because the resistance during demolding comes from the adhesion between the outer surface and the skin, and the friction between the contact surfaces of the segments. The adhesive constraint on the outer surface can only be alleviated by the release cloth and release agent. Therefore, the focus is on adjusting the priority (the core mold 4 is assembled as a whole along the circumferential direction; during demolding, the segments need to move radially towards the axis to be removed. During this process, the segments are mutually constrained. Segments that reduce the friction between the contact surfaces under tension are removed first, and the remaining segments, no longer constrained, can be removed successively. The first part removed is called the priority). The deflection angle α of the contact surface (inclined surface) of the segments (i.e., the angle between the contact surface and the radius perpendicular to the chord of the segment's cross-section, such as...) is also important. Figure 6As shown, the deflection angle α is set to 30°-45°, so that the tangential friction force between the contact surfaces is biased towards the direction of the pulling force during demolding. In the segmented design, it is also necessary to ensure that the size of the segments is as close as possible (obviously, the size of segments of different structures cannot be completely consistent, in which case the preferred segment can be slightly smaller), and the preferred arc surface segment 5 should be evenly arranged alternately with other non-preferred arc surface segments 6.

[0046] Step 3: Assemble the core mold 4; Assemble multiple core molds 4 sequentially from one end to the other on the outer surface of the steel shaft 3, specifically as follows:

[0047] First, assemble the first mandrel 4 on the outer circumference of one end of the steel shaft 3. The first mandrel 4 is bonded to the steel shaft 3. Then, clamp a positioning block (consisting of two semi-circular positioning blocks, clamped together on the outer circumference of the steel shaft 3) with the width of the rib to be wound. This positioning block is close to the first mandrel. Next, assemble the second mandrel on the outer circumference of the steel shaft 3. The second mandrel is close to the positioning block and bonded to the steel shaft 3. Finally, remove the first mandrel and... The positioning block between the second core mold is then clamped and fixed on the outer circular surface of the steel shaft 3. The positioning block is the same width as the rib to be wound. This positioning block is set close to the second core mold. Then, the third core mold is assembled on the outer circular surface of the steel shaft 3. The third core mold is set close to the positioning block and is bonded to the steel shaft 3. Then, the positioning block between the second and third core molds is removed. This process is repeated until the last core mold 4 is assembled and bonded to the steel shaft 3. Finally, the positioning block adjacent to the last core mold 4 is removed.

[0048] The simplicity of assembling the core mold 4 is an advantage of this method. The core mold 4 is divided into segments with only two alternating structures along the circumferential direction. Furthermore, it only needs to be fixed to the steel shaft according to the stiffening parameters (stiffening width and stiffening spacing). The stiffening width (i.e., the width required between two adjacent core molds 4) is positioned using positioning blocks to ensure the accuracy of the stiffening width. The stiffening spacing, i.e., the width of the core mold 4, only requires fixing the corresponding width core mold 4 according to the stiffening spacing at different positions. Since the steel shaft 3 is a smooth shaft, the core mold 4 cannot be fixed by mechanical connection. This method chooses adhesive fixing (or a soft film can be used to wrap the outer circumference of the core mold 4). For the adhesive, the requirements are firstly that it can be used to bond the steel shaft 3 to the corresponding core mold 4 material. More importantly, it is necessary to find an adhesive that fails or degrades at the curing temperature, that is, to ensure stable bonding when wound at room temperature, and to fail after curing so as to facilitate the removal of the steel shaft 3. The core mold 4 is bonded to the steel shaft 3 (spot bonding is sufficient, it is recommended to use 2-4 adhesive dots to bond each arc surface segment to the steel shaft 3). The outer circumferential surface of the core mold 4 is in contact with the pressure-resistant shell skin 1. The porous material core mold 4 can be covered with adhesive release cloth (the adhesive release cloth is fixed on the outer circumferential surface of the core mold), while the dense material core mold 4 can be coated with release agent.

[0049] Step 4: Integral molding of the reinforced pressure-resistant shell; Yarn is wound into the annular space between each pair of adjacent core molds 4. When the yarn is wound to be roughly the same as the outer diameter of the core mold 4, a rib is formed. The outer diameter of the rib is trimmed (simple manual trimming) so that the outer contour of the rib matches the outer contour of the core mold 4 (the diameter is consistent). Then, a skin 1 is wound around the outer circumference of the rib and the core mold 4. When the wound skin 1 reaches the designed thickness, it is cured and molded (the curing and molding process is the existing process) to produce the reinforced pressure-resistant shell molded body.

[0050] This method differs from common staged molding (in staged molding, the ribs are first wound and cured, then prepreg is laid; if prepreg is used entirely to prepare the skin, it can be formed after secondary curing; if the winding process is used to prepare the skin, yarn needs to be wound on the surface after the prepreg is laid and cured twice, followed by a third curing, which is obviously more complicated). In this method, the ribs and skin 1 are wound in sequence in one go, and then cured to form the shell. The integrated molding process of the pressure-resistant shell is simpler, the bonding between the ribs and skin 1 is better, and the resin penetrates the gap between the ribs and skin 1, reducing internal damage.

[0051] Taking a ring-rib pressure-resistant shell as an example, the winding of the rib is carried out by first calculating the theoretical number of turns of the yarn to be wound based on the cross-sectional area of ​​the rib and the number and surface density of the yarn. Then, according to the laying angle of the rib in the pressure-resistant shell structure (the laying angle of the rib is 90°), the winding angle of the yarn in the winding machine is set. After the outer diameter of the rib is wound to be roughly consistent with the outer diameter of the core mold 4, the outer diameter of the rib is then appropriately adjusted so that the outer contour of the rib matches the outer contour of the core mold 4 better. The next step is to wind the skin 1.

[0052] The skin 1 is wound layer by layer according to the designed layup scheme (including the thickness of skin 1, different layup angles, proportions and distributions). Finally, the ends of the pressure shell are repaired by winding, and then the entire skin is wound for the last time, leaving room for subsequent machining.

[0053] Step 5: Demolding of core mold 4; First, remove the steel shaft 3 of the reinforced pressure shell molding body, and then remove all the arc surface segments of core mold 4 to make a composite material reinforced pressure shell; The disassembly sequence of all the arc surface segments of core mold 4 is: first disassemble the priority arc surface segment 5, and then disassemble the non-priority arc surface segment 6.

[0054] Based on factors such as the performance requirements of the pressure shell, the material of the core mold 4, the operating space, and the structure of the core mold 4, different demolding schemes can be selected, such as direct mechanical or manual destruction, chemical or physical dissolution, spiral-shaped screw-in tool 7 (during the spiral-shaped screw-in tool 7's screw-in process, the top of the spiral-shaped screw-in tool 7 will push against the inner side of the skin 1; at this time, if the spiral-shaped screw-in tool 7 continues to rotate, the spiral-shaped screw-in tool 7 will not advance further, but will cause the core mold 4 to be pulled out by the spiral-shaped screw-in tool 7), pre-embedded adhesive tape 8 (in order to pull the pre-embedded adhesive tape 8 to release the core mold 4 during demolding, for example, "I" or "+" shaped pre-embedded adhesive tapes are placed in the middle position of the outer circumference of the core mold 4, and double rows of parallel adhesive tapes are pre-embedded at equal intervals; based on this function, the pre-embedded material does not have to be adhesive tape, as long as it is strip-shaped, and it has no substitution relationship with the adhesive demolding cloth and the adhesive fixing the core mold 4 to the steel shaft 3), pull-out (such as... Figure 13 and Figure 14 The diagram shows a double-row tape arrangement. Other arrangements include single-row, cross-shaped, and star-shaped tape arrangements. Some materials of the core mold 4 (such as polytetrafluoroethylene, nylon, and polyoxymethylene) can also have pre-drilled threaded holes on the arc-shaped surface segments, which can be pushed out by bolts 10 or pulled out by auxiliary tools 11. The above arrangements can be selected, but are not limited to them.

[0055] For reinforced pressure shells with limited operating space, the core mold 4 can be made of a lower-priced material (such as polystyrene foam, polyurethane foam, or acrylate), which can be mechanically destroyed after molding. Alternatively, a material that is easily dissolved by certain solutions (acid or alkali solutions, etc.) can be selected and dissolved directly without affecting or minimally affecting the pressure shell, followed by rinsing the pressure shell with clean water.

[0056] For applications with a large operating space and where the core mold 4 needs to be used a limited number of times in a short period of time, the core mold 4 can be made of a relatively stable material, such as PMI foam, and the specific model can be determined based on the tension (considering hardness). For porous materials such as foam, an adhesive release cloth can be wrapped around it and the release cloth can be replaced after each demolding. Demolding solutions can include pre-embedded tape 8 with different laying patterns, spiral screw-in tooling 7, etc.

[0057] Pre-embedded adhesive tape 8 is laid between the adhesive release cloth and the core mold 4. Except for the portion embedded in the surface of the core mold 4, the ends of the pre-embedded adhesive tape 8 are reserved for appropriate lengths to ensure easy pulling down during demolding. A groove is cut into the inner arc surface of the core mold 4, with the groove direction consistent with the laying direction of the pre-embedded adhesive tape 8. The groove depth should be within 3mm. The purpose of the groove is to embed the reserved lengths of pre-embedded adhesive tape 8 inside the groove. After the steel shaft 3 is removed, the reserved portion of the pre-embedded adhesive tape 8 embedded in the groove is taken out for subsequent pulling during demolding of the core mold 4. The reserved portion of the pre-embedded adhesive tape 8 is embedded in the groove to avoid gaps between the core mold 4 and the steel shaft 3, which could cause resin to flow in and affect demolding and the accuracy of the reinforcing ribs.

[0058] For applications requiring high precision and long-term use of the core mold 4, materials such as polytetrafluoroethylene, nylon, or other plastics can be selected. These materials offer better machinability, more stable structures, and are less prone to deformation. For demolding, threaded holes can be pre-drilled in the core mold 4, and the core mold 4 can be ejected by screwing in the bolt 10 or pulled out by the auxiliary tool 11. Unlike foam materials, which cannot be perforated and thus leave irreparable small holes, this method avoids such issues.

[0059] Specific Implementation Method Two: This implementation method is a further explanation of Specific Implementation Method One. In step one, the plastic is one of polytetrafluoroethylene, nylon, polyoxymethylene, and PVC, or a combination of at least two materials; the foam is one of PMI foam, high-strength polyurethane foam, polystyrene foam, acrylate foam, and polyvinyl chloride foam, or a combination of at least two materials.

[0060] Focusing on plastic materials, this method suggests selecting either a single material or a combination of two or more materials (Note: As seen in the ribbed pressure shell, the circumferential regions between the ribs are independent; multiple material combinations refer to selecting different materials for different circumferential regions). Firstly, the selected materials are all lightweight. Secondly, considering key factors in the pressure shell manufacturing process, including yarn winding tension and curing temperature, the core mold 4 is selected from materials with different hardness and temperature resistance, such as PMI foam, high-strength polyurethane foam, polytetrafluoroethylene, and nylon. Secondary factors include the structural dimensions of the pressure shell (inner diameter, rib height, rib spacing, and length).

[0061] Furthermore, the yarn winding tension requirement for mandrel 4 dictates that its hardness must ensure structural stability, preventing localized dents and overall deformation under the action of the yarn. The curing temperature requirement dictates that the selected material's temperature resistance must be above the curing temperature (it is recommended that the material's temperature resistance be 15%–20% higher than the curing temperature). The dimensions of the pressure shell structure affect the demolding operation space, especially for the length of the pressure shell. Obviously, the working depth of manual operation is limited. For different pressure shell lengths, different demolding methods may be required for the central area (including manual removal, manual destruction removal, and mechanical destruction removal). To address this, different materials can be used in the central area and on both sides of the pressure shell (for example, it is recommended to choose a material with lower hardness, such as polyurethane foam or polystyrene foam, to ensure that it can be destroyed by ordinary tools; in addition, since the material is used only once, cost also needs to be considered).

[0062] Specific Implementation Method 3: This implementation method is a further explanation of Specific Implementation Method 1 or 2. In step 2, the number of segments of the multiple arc surfaces of the core mold 4 is 6, 8 or 10.

[0063] Example 1:

[0064] This embodiment describes a composite material ring-ribbed pressure-resistant shell core mold design and shell integral molding method (pressure-resistant shell structural parameters: length approximately 1700mm, inner diameter approximately 300mm, number of ribs 7, with varying rib widths and spacings; rib widths from left to right are 20, 15, 15, 20, 15, 15, 20mm; rib height 16mm; rib spacing 180, 160, 155, 155, 160, 180mm, etc.). Figure 1 (As shown), the specific steps are as follows:

[0065] Step 1, Core mold material selection:

[0066] Compared to the complex assembly and demolding sequence of traditional steel core molds, this embodiment selects PMI foam as the core mold material. Its advantages are simple assembly, easy to master and operate, quick structural design and short processing cycle. This foam material has a low density, which greatly reduces the core mold segmentation and overall weight. It can prepare larger pressure-resistant shell structures within the load-bearing range of the winding machine. In addition, the pretreatment, assembly and transportation work is also reduced. Furthermore, there are many types of foam materials, and the same type has many models (corresponding to different hardness), which can adapt to different winding tensions.

[0067] Step 2, Core mold 4 structure design:

[0068] Considering the segment size and assembly accuracy of the core mold, it is divided into 8 arc-shaped segments in the circumferential direction, such as... Figure 4 , Figure 5 As shown. The segmented structure is divided into two types, each accounting for 50% (the preferred type, the arc-shaped surface segment 5, has 4 segments). The sizes of the two segments are similar (the preferred type, the arc-shaped surface segment 5, is slightly smaller), and they are distributed alternately. The deflection angle α of the inclined surface (contact surface) of the preferred type, the arc-shaped surface segment 5, is approximately 30°.

[0069] Step 3, core mold 4 assembly:

[0070] PMI foam is a porous material, and liquid release agents cannot be applied. Therefore, firstly, adhesive release cloth is wrapped around each segment surface (the surfaces including the surfaces where the core mold 4 contacts the ribs and skin 1, and the contact surfaces between segments are all covered with adhesive release cloth), leaving only the inner surface of the core mold 4 in contact with the steel shaft 3. Then, the segments are successively bonded along the circumference of the steel shaft 3 (only the inner surfaces of the core mold segments are bonded to the steel shaft 3; the other surfaces do not need to be bonded). Figure 2 and Figure 3 As shown, a release agent is finally applied to the surface in contact with the composite material (the outer surface of the core mold 4) (mainly to ensure easy demolding as much as possible). After fixing it to the steel shaft 3, the release agent is applied three more times.

[0071] Step 4, integral molding of reinforced pressure-resistant shell:

[0072] The theoretical number of yarn winding turns is calculated based on the cross-sectional area of ​​the rib, the surface density of the yarn, and the volume fraction of the resin in the composite material. The loop rib 2 is wound, and when the outer contour of the loop rib 2 is close to the core mold 4, local adjustments are made. Next, the skin 1 is wound, with machining allowances reserved in length and outer diameter.

[0073] Step 5, Demolding solution for core mold 4:

[0074] First, the steel shaft 3 is removed using a hydraulic demolding machine. At this point, the inner side of the pressure shell is exposed, revealing the inner side of the ribs, while the space between the ribs is still filled by the core mold 4. The core mold 4 is then demolded. In this embodiment, a spiral-shaped screw-in tooling 7 is selected for demolding, such as... Figure 12 As shown. The reason for choosing this demolding solution is that the hardness of PMI foam is at a suitable level. The spiral-shaped screw-in tool 7 can be easily and smoothly screwed into the interior of PMI foam without breaking like ordinary foam, thus ensuring the integrity of the structure. After demolding, only small drill holes will be generated on the inner and outer surfaces of the core mold 4, which will not affect subsequent use (limited use).

[0075] Furthermore, when using the spiral-shaped screw-in tooling 7, it is recommended to first screw in the core mold 4 near the boundary of the rib, causing the part of the core mold 4 near the rib to lift up, and continue screwing in towards the center to completely eject the segments of the core mold 4. Alternatively, a screwdriver can be used to pry them out. First eject the preferred arc surface segment 5, and then eject the non-preferred arc surface segment 6.

[0076] Example 2:

[0077] This embodiment discloses a method for designing a composite material mesh-reinforced pressure shell mandrel and integrally molding the shell, the specific steps of which are as follows:

[0078] Step 1, Material selection for core mold 4:

[0079] This solution selects polytetrafluoroethylene (PTFE), which has greater hardness and more stable structure than foam materials, enabling long-term use and facilitating adjustments to the demolding process.

[0080] Step 2, Core mold 4 structure design:

[0081] The design standards are the same as step 2 in Example 1;

[0082] Furthermore, due to the high hardness of polytetrafluoroethylene (PTFE), it is feasible to machine it. Therefore, threaded holes are to be drilled. One through-thickness M8 threaded hole is drilled at the center of each segment of the mandrel 4. On both sides of this segment's threaded hole, along the long axis, one through-thickness M6 threaded hole is drilled near each end. Figure 17 As shown;

[0083] Step 3, core mold 4 assembly:

[0084] Unlike the porous nature of foam, polytetrafluoroethylene does not require covering with adhesive release cloth. The segments are directly bonded together one by one along the circumference of the steel shaft 3, and then release agent is applied to the remaining contact surfaces of the core mold 4.

[0085] Step 4, integral molding of reinforced pressure-resistant shell:

[0086] The process of winding the mesh reinforcement 9 is the same as step 4 in Example 1, except that the angle of the reinforcement can be adjusted in the parameter settings of the winding machine (e.g., ...). Figure 15 , Figure 16 (As shown).

[0087] Step 5, Demolding solution for core mold 4:

[0088] First, use a demolding machine to remove the steel shaft 3. Then, screw the M6 ​​and M8 bolts 10 into their corresponding threaded holes until the bolts 10 are against the inside of the pressure-resistant shell skin 1. Alternately screw in each bolt 10 (at this point, all threaded holes have been screwed into the bolts 10, and all bolts 10 have contacted the skin 1; continue to screw in alternately. The purpose of continuing to screw in is that if the core mold 4 and the mesh reinforcement 9 are loosely constrained, the core mold 4 can be pulled out by the rotating thread, similar to the spiral screwing tool 7 used in PMI foam. When the bolts 10 are against the skin 1 and cannot move forward, continuing to rotate will obviously push the core mold 4 out in the opposite direction because the two have a mutual motion relationship). The purpose is to make the core mold 4 and the skin 1 bear force evenly, avoid damaging the threads and the skin 1, and allow the core mold 4 to be steadily pushed out. Figure 18 As shown;

[0089] Furthermore, to prevent the bolts 10 from excessively compressing the skin 1 due to the core mold 4 being too tightly fixed, the auxiliary tool 11 can be screwed onto the core mold 4 via the bolts 10 at an appropriate time, such as... Figure 19 As shown, tension is used to facilitate the ejection of the core mold 4.

[0090] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0091] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for integrally molding a composite material reinforced pressure-resistant shell, characterized in that: The method includes the following steps: Step 1, Selection of core mold (4) material; use foam or plastic as core mold (4) material; plastic is one of polytetrafluoroethylene, nylon, polyoxymethylene, PVC, or a combination of at least two materials; foam is one of PMI foam, high-strength polyurethane foam, polystyrene foam, acrylate foam, polyvinyl chloride foam, or a combination of at least two materials; Step 2, core mold (4) structure design; the core mold (4) is assembled by arranging multiple arc surface segments in sequence along the circumference. The multiple arc surface segments are composed of multiple preferred arc surface segments (5) and multiple non-preferred arc surface segments (6). The multiple preferred arc surface segments (5) and multiple non-preferred arc surface segments (6) are arranged alternately along the circumference. The contact surfaces of the preferred arc surface segments (5) and the non-preferred arc surface segments (6) are all inclined surfaces. The deflection angle α of the inclined surface of the preferred arc surface segment (5) is 30°-45°. Step 3: Assembly of the core mold (4); Multiple core molds (4) are assembled sequentially from one end to the other on the outer surface of the steel shaft (3). Specifically, the first core mold (4) is assembled on the outer surface of one end of the steel shaft (3), and the first core mold (4) is bonded to the steel shaft (3). Then, a positioning block with the same width as the rib to be wound is clamped on the outer surface of the steel shaft (3). The positioning block is set close to the first core mold. After that, the second core mold is assembled on the outer surface of the steel shaft (3). The second core mold is set close to the positioning block and bonded to the steel shaft (3). After that, the first core mold is removed. A positioning block between the first core mold and the second core mold is used. Then, a positioning block with the same width as the rib to be wound is clamped and fixed on the outer circle surface of the steel shaft (3). The positioning block is set close to the second core mold. Then, the third core mold is assembled on the outer circle surface of the steel shaft (3). The third core mold is set close to the positioning block and is bonded to the steel shaft (3). Then, the positioning block between the second core mold and the third core mold is removed. This process is repeated until the last core mold (4) is assembled and bonded to the steel shaft (3). Finally, the positioning block adjacent to the last core mold (4) is removed. Step 4: Integral molding of reinforced pressure-resistant shell; Wrap yarn in the annular space between each pair of adjacent core molds (4). When the yarn is wound to the same diameter as the outer diameter of the core mold (4), a rib is formed. The outer diameter of the rib is adjusted so that the outer contour of the rib matches the outer contour of the core mold (4). Then, wrap a skin (1) around the outer circumference of the rib and the core mold (4). When the wrapped skin (1) reaches the designed thickness, it is cured and molded to form a reinforced pressure-resistant shell. Step 5: Demolding of core mold (4); First, pull out the steel shaft (3) of the reinforced pressure shell molding body, and then remove all the arc surface segments of the core mold (4) to make a composite material reinforced pressure shell; The disassembly sequence of all the arc surface segments of the core mold (4) is: first disassemble the priority arc surface segments (5), and then disassemble the non-priority arc surface segments (6).

2. The method for integral molding of a composite material reinforced pressure-resistant shell according to claim 1, characterized in that: In step two, the number of segments of the multiple arc surfaces of the core mold (4) is 6, 8 or 10.

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