A sandwich-insulated composite material launch box rubber base limiting cover and its preparation method

Abstract

This invention provides a sandwich-type thermally insulated composite material launch box rubber base limiting cover and its preparation method. The limiting cover includes a sidewall and a separation body. The sidewall includes an inner sidewall skin, a sidewall core material, and an outer sidewall skin. The sidewall core material has a composite material layer near the end of the separation body, and multiple metal sheets are arranged circumferentially along the upper edge of the composite material layer near the end of the separation body. The separation body includes an inner separation body skin, a separation body core material, and an outer separation body skin. The core material of the separation body has a release cloth layer near the end of the sidewall. The composite material layer is connected to the release cloth layer. A gap is provided between the inner sidewall skin and the inner separation body skin, and the gap is filled with resin. A gap is provided between the outer sidewall skin and the outer separation body skin, and the gap is filled with a heat-resistant coating. This limiting cover meets the requirements of load-bearing capacity, high and low temperature deformation, tensile separation, and thermal insulation. It does not break under a tensile force of 40kN under storage conditions. During operation, under the expansion of the rubber base, the separation body can break under a tensile force not exceeding 120kN.

Description

Technical Field

[0001] This invention belongs to the field of box-type launch and protection technology, specifically relating to a sandwich-insulated composite material launch box rubber base limiting cover and its preparation method. Background Technology

[0002] The rubber base retaining cover of the launch box, as one of the main components of the box-type launch assembly, is installed on the front and rear flanges of the launch box. During routine storage, it provides sealing and airtight protection for the launch box. During operation, under the combined action of the relatively small breaking force of the launch vehicle and the exhaust gas flow, the front retaining cover breaks into several segments along the pre-designed stress concentration groove and is ejected in all directions, clearing a path for the launch vehicle to exit the box smoothly. The rear retaining cover separates along the pre-designed separation zone, opening a path for exhaust gas flow. Compared with traditional mechanical opening and explosive bolt opening methods, the composite rubber base retaining cover has advantages such as shorter opening speed, lighter separation mass, and stronger environmental adaptability, and is increasingly being used in the field of box-type launch vehicles.

[0003] To enable the composite fragile cover to crack along pre-designed stress concentration grooves, researchers both domestically and internationally have primarily employed methods such as designing different types of stress concentration grooves on the limiting cover, or cutting the entire separation body along the separation point and then bonding it back together with adhesive along the original cut lines, followed by local reinforcement in the cut area to meet the requirements of different separation conditions. However, under long-term storage conditions, the product experiences cyclical changes in air pressure load and environmental temperature and humidity, which can cause fatigue creep at the stress concentration points or debonding at the adhesive points, leading to fatigue creep damage. This severely affects the long-term airtight reliability of the launch box, posing a potential safety challenge to the long-term reliability of the composite fragile cover. Furthermore, the product manufacturing process is complex, involves many manual processes, and has significant product quality variability.

[0004] Patent CN 103913098 A discloses a multi-lobed composite material launch box cover and its manufacturing method. A 45° stress concentration groove is prepared between each cut, separated sub-lobes and between the sub-lobes and the frame. These are then bonded together with AB adhesive, and fiber strips are used for local reinforcement between the sub-lobes. Patent CN 104913692 A discloses a fragile cover with a shell shaped like a regular square truncated pyramid. Stress grooves, arranged in an integral cross shape, are provided at the four corners of its inner wall. The centers of these cross-shaped stress grooves and the annular stress grooves coincide to meet separation requirements. The aforementioned fragile cover is made by preparing a stress concentration groove or a combination of stress concentration groove and adhesive bonding to prepare the launch box rubber base limiting cover. This method is mostly used for thin film limiting covers with a relatively thin separation zone, and rarely used for limiting covers with a thicker separation zone or for the separation zone of composite material sandwich layers. In addition, the stress groove of the product is a stress concentration area, which is prone to periodic fatigue damage under long-term load and temperature coupling. Furthermore, the adhesive bonding process and the preparation process of the local reinforcement layer are not easy to control and are greatly affected by the operation of personnel during the preparation process. This makes the long-term airtightness of the product unreliable, the quality unstable, and the production process complex and difficult to control. Therefore, it is particularly important to design a new type of launch box rubber base limiting cover with a new separation method. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a sandwich-insulated composite material launch box rubber base limiting cover and its preparation method. By designing the product's pressure-bearing structure, the product meets the requirements of load bearing, high and low temperature deformation, tensile separation and heat preservation, effectively limiting the expansion deformation of the internal rubber base. At the same time, during operation, under the expansion of the rubber base, the bottom separation body of the composite material launch box rubber base limiting cover can be pulled apart along the pre-designed position.

[0006] To address the aforementioned problems, a first aspect of the present invention provides a rubber base limiting cover for a sandwich-insulated composite material launch box, comprising an annular sidewall and a separable body connected to the bottom of the sidewall; the sidewall comprises an inner sidewall skin, a sidewall core material, and an outer sidewall skin arranged and connected sequentially from the inside to the outside, wherein an annular composite material layer is disposed and connected to one end of the sidewall core material near the separable body, and a plurality of metal sheets are spaced circumferentially along the end of the composite material layer near the separable body; the separable body comprises an inner separable body skin, a separable body core material, and an outer separable body skin arranged and connected sequentially from the inside to the outside, wherein an annular release fabric layer is disposed and connected to one end of the separable body core material near the sidewall, the adhesive surface of the release fabric layer facing the separable body core material; the composite material layer is connected to the release fabric layer; a first annular gap is provided between the inner sidewall skin and the inner separable body skin, the first annular gap being filled with resin; a second annular gap is provided between the outer sidewall skin and the outer separable body skin, the second annular gap being filled with a heat-resistant coating.

[0007] Preferably, the plurality of metal sheets are arranged at equal intervals in the circumferential direction of the composite material layer.

[0008] Preferably, the angle between the line connecting the adjacent metal sheet and the center of the composite material layer is 45°.

[0009] Preferably, the core material of the separator has multiple composite material reinforcing ribs on the side near the outer skin of the separator.

[0010] Preferably, the inner sidewall skin and the inner separator skin are made of carbon fiber reinforced resin matrix composite material; the outer sidewall skin and the outer separator skin are made of glass fiber reinforced resin matrix composite material; and the sidewall core material and the separator core material are polyurethane foam.

[0011] Preferably, the thickness of the inner sidewall skin and the inner separator skin is 1.7-2.3 mm; the thickness of the outer sidewall skin and the outer separator skin is 2.7-3.3 mm; and the thickness of the sidewall core material and the separator core material is 28-32 mm.

[0012] Preferably, the metal sheet has a length of 40-60 mm, a width of 25-30 mm, and a thickness of 0.1-0.5 mm.

[0013] Preferably, the plurality of composite material reinforcing ribs are arranged in a grid pattern; each reinforcing rib has a width of 40 mm and a thickness of 8.3-31 mm.

[0014] A second aspect of the present invention provides a method for preparing a rubber base limiting cover for a sandwich-insulated composite material launch box, the rubber base limiting cover for the sandwich-insulated composite material launch box comprising an annular sidewall and a separate body connected to the bottom of the sidewall; the preparation method comprises the following steps:

[0015] S1. A first reinforcing material layer is integrally provided on the surface of the male mold used for molding the rubber base limiting cover of the composite material launch box, and the first reinforcing material layer is impregnated with resin.

[0016] S2. The core material and sidewall core material of the separated body are placed on the first reinforcing material layer impregnated with resin;

[0017] S3. The first reinforcing material layer is cut at the junction of the sidewall and the separated body, leaving a gap, to divide it into an inner skin of the sidewall and an inner skin of the separated body; an annular release cloth layer, multiple metal sheets, and an annular second reinforcing material layer are arranged sequentially in the area between the core material of the separated body and the core material of the sidewall, and the second reinforcing material layer is impregnated with resin; the release cloth layer is located on the outside of the inner skin of the separated body and is bonded to the core material of the separated body; the second reinforcing material layer is located on the outside of the inner skin of the sidewall, and multiple metal sheets are arranged at intervals along the circumferential direction of the reinforcing material layer;

[0018] S4. A third reinforcing material layer of the outer skin of the launch box rubber base limiting cover is provided on the outside of the core material of the separated body and the side wall core material, and the third reinforcing material layer is impregnated with resin;

[0019] S5. The male mold and female mold are joined together and then cured. The outer skin of the launch box rubber base limiting cover is then processed and broken at the junction of the side wall and the separate body, dividing it into the side wall outer skin and the separate body outer skin. A heat-resistant coating is filled between the side wall outer skin and the separate body outer skin. After curing, the sandwich thermal insulation composite material launch box rubber base limiting cover is obtained.

[0020] Preferably, before step S4, a reinforcing rib groove is processed on the outer surface of the core material of the separated body, and a reinforcing rib reinforcement material is placed in the reinforcing rib groove and impregnated with resin.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The present invention relates to a sandwich-insulated composite material launch box rubber base limiting cover. The side wall of the rubber base limiting cover and the bottom separation body are connected by a release cloth, a metal sheet and a composite material layer. The release cloth, the metal sheet and the composite material layer form the separation area of ​​the rubber base limiting cover. The adhesive surface of the release cloth is bonded to the core material of the separation body. The smooth surface of the release cloth is bonded to the composite material layer by the resin in the composite material layer before curing. The metal sheet is spaced between the composite material layer and the release cloth layer and is bonded to the composite material layer by the resin in the composite material layer before curing. Because the smooth surface of the release fabric layer has a certain adhesive force with the resin in the composite material layer, this adhesive force ensures that the separator will not separate from the sidewall under the coupled changes of cyclical gas pressure load rise and fall and ambient temperature and humidity under long-term storage conditions, limiting the expansion and deformation of the rubber base under the stored gas. However, its connection strength is weaker than that of a complete composite material structure, and the adhesion strength between the metal sheet and the resin in the composite material layer is weak, which can form multiple connection defect areas between the release fabric layer and the composite material layer. Therefore, under the expansion of the rubber base during operation, the separator can separate from the sidewall under a certain tensile force, resulting in high reliability of the product during breakage. In addition, the rubber base limiting cover of this sandwich insulated composite material launch box has a sandwich structure with a core material between the inner and outer skins. The thermal insulation performance of the rubber base limiting cover of the launch box can be improved by selecting an appropriate core material.

[0023] The sandwich-insulated composite material launch box rubber base limiting cover of the present invention can limit the expansion and deformation of the rubber base under the stored gas. Under a tensile force of 40kN, the product separation area will not be damaged. During operation, under the expansion and deformation of the rubber base, the limiting cover can reliably separate under a specified tensile force not exceeding 120kN. During high and low temperature tests, its interior can withstand a tensile force of (15-20)kN without structural damage. At -40℃, after 8 hours of heat preservation, the maximum deformation at the center point and the lowest point of the structure is no greater than 5mm and 2mm, respectively. At 60℃, after 8 hours of heat preservation, the maximum deformation at the center point and the lowest point of the structure is no greater than 10mm and 5mm, respectively. Furthermore, the tensile force can be adjusted by further adjusting the width and length of the polytetrafluoroethylene release cloth and the copper sheet. Attached Figure Description

[0024] Figure 1 This is a cross-sectional view of the separation area of ​​the rubber base limiting cover of the sandwich-insulated composite material launch box according to an embodiment of the present invention;

[0025] Figure 2 This is a cross-sectional view of the rubber base limiting cover of the sandwich-insulated composite material launch box according to an embodiment of the present invention;

[0026] Figure 3 This is a front view of the rubber base limiting cover of the sandwich-insulated composite material launch box according to an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram showing the arrangement of copper sheets on the core material of the separator in the rubber base limiting cover of the sandwich thermal insulation composite material launch box according to an embodiment of the present invention.

[0028] Wherein: 1-Sidewall; 11-Inner skin of sidewall; 12-Core material of sidewall; 13-Outer skin of sidewall; 2-Separation body; 21-Inner skin of separation body; 22-Core material of separation body; 23-Outer skin of separation body; 3-Composite material layer; 4-Copper sheet; 5-Release cloth layer; 6-Silicone rubber heat-resistant coating; 7-Separation zone; 8-Reinforcing rib. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Currently, most existing launch box rubber base limiting covers use stress concentration grooves or a combination of stress concentration grooves and adhesive bonding. This method is suitable for thin film rubber base limiting covers with relatively thin separation zones, but rarely used for rubber base limiting covers with thicker separation zones or for the separation zones of sandwich structures. Furthermore, as stress concentration areas, stress grooves are prone to periodic fatigue damage under long-term load and temperature coupling, making the long-term airtightness of the product unreliable and the quality unstable.

[0031] To this end, a first aspect of the present invention provides a rubber base limiting cover for a sandwich-insulated composite material launch box, comprising an annular sidewall and a separable body connected to the bottom of the sidewall; the sidewall comprises an inner sidewall skin, a sidewall core material, and an outer sidewall skin arranged and connected sequentially from the inside to the outside, an annular composite material layer is provided and connected to one end of the sidewall core material near the separable body, and a plurality of metal sheets are spaced circumferentially along one end of the composite material layer near the separable body; the separable body comprises an inner separable body skin, a separable body core material, and an outer separable body skin arranged and connected sequentially from the inside to the outside, an annular release cloth layer is provided and connected to one end of the separable body core material near the sidewall, the adhesive surface of the release cloth layer facing the separable body core material; the composite material layer is connected to the release cloth layer; a first annular gap is provided between the inner sidewall skin and the inner separable body skin, the first annular gap being filled with resin; a second annular gap is provided between the outer sidewall skin and the outer separable body skin, the second annular gap being filled with a heat-resistant coating.

[0032] In this embodiment of the invention, the sidewall of the rubber base limiting cover of the sandwich-insulated composite material launch box is connected to the bottom separation body through a release cloth, a metal sheet, and a composite material layer. The release cloth, the metal sheet, and the composite material layer form the separation area of ​​the rubber base limiting cover. The adhesive surface of the release cloth is bonded to the core material of the separation body, and the smooth surface of the release cloth is bonded to the composite material layer through the resin in the composite material layer before curing. The metal sheet is spaced between the composite material layer and the release cloth layer and is bonded to the composite material layer through the resin in the composite material layer before curing. Because the smooth surface of the release fabric layer has a certain adhesive force with the resin in the composite material layer, this adhesive force ensures that the separator will not separate from the sidewall under the coupled changes of cyclical gas pressure load rise and fall and ambient temperature and humidity under long-term storage conditions, limiting the expansion and deformation of the rubber base under the stored gas. However, its connection strength is weaker than that of a complete composite material structure, and the adhesion strength between the metal sheet and the resin in the composite material layer is weak, which can form multiple connection defect areas between the release fabric layer and the composite material layer. Therefore, under the expansion of the rubber base during operation, the separator can separate from the sidewall under a certain tensile force, resulting in high reliability of the product during breakage. In addition, the rubber base limiting cover of this sandwich insulated composite material launch box has a sandwich structure with a core material between the inner and outer skins. The thermal insulation performance of the rubber base limiting cover of the launch box can be improved by selecting an appropriate core material.

[0033] In some embodiments, the thickness of the inner and outer skins of the sidewall and the separator, and the thickness of the core of the sidewall and the separator can be adjusted according to actual needs. Preferably, the thickness of the inner skin of the sidewall and the inner skin of the separator is 1.7-2.3 mm; the thickness of the outer skin of the sidewall and the outer skin of the separator is 2.7-3.3 mm; and the thickness of the core material of the sidewall and the core material of the separator is 28-32 mm.

[0034] In some embodiments, the materials of the inner and outer skins of the sidewalls and the separator can be different composite materials depending on the requirements for the product's strength, high-temperature resistance, and ablation resistance. Preferably, the inner skin of the sidewalls and the inner skin of the separator are made of carbon fiber reinforced resin matrix composite material; the outer skin of the sidewalls and the outer skin of the separator are made of glass fiber reinforced resin matrix composite material. Using carbon fiber reinforced composite material for the inner skin and glass fiber reinforced composite material for the outer skin, a hybrid composition of carbon fiber and glass fiber is employed, ensuring the product's load-bearing strength while minimizing its weight; furthermore, it reflects the cost-effectiveness requirements of the product design. The core material of the sidewalls and the core material of the separator can be selected from different materials depending on the requirements for thermal insulation performance. Preferably, the core material of the sidewalls and the core material of the separator are polyurethane foam. Polyurethane foam has good thermal insulation properties, enabling the launch box to have better thermal insulation effects.

[0035] In some embodiments, the arrangement of the metal sheets in the circumferential direction of the composite material layer can be adjusted; they can be arranged at equal intervals or at unequal intervals. Preferably, multiple metal sheets are arranged at equal intervals in the circumferential direction of the composite material layer, which can make the connection force defect area uniformly distributed and further improve the tensile strength reliability.

[0036] In some embodiments, the spacing between adjacent metal sheets, i.e., the angle between the line connecting adjacent metal sheets and the center of the composite material layer, can be adjusted according to the required tensile strength. For example, the angle can be 30° with 12 metal sheets, or the angle can be 60° with 6 metal sheets. The rubber base limiting cover of the sandwich insulation composite material launch box designed in this application needs to ensure that the product separation area will not be damaged under a tensile strength of 40KN and can be reliably separated under a tensile strength of no more than 120KN. Preferably, the angle between the line connecting adjacent metal sheets and the center of the composite material layer is 45°, i.e., 8 metal sheets are equally spaced, and the line connecting the 8 metal sheets and their center point forms a star shape, which can meet the above tensile strength requirements.

[0037] The length, width, and thickness of the metal sheet can be adjusted according to the required breaking force. Preferably, the length of the metal sheet is 40-60mm (50mm), the width is 25-30mm (28mm), and the thickness is 0.1-0.5mm; more preferably, the length of the metal sheet is 50mm and the width is 28mm.

[0038] The range of materials that can be selected for the metal sheet is relatively wide. For example, copper sheets or iron sheets can be used. Preferably, copper sheets are used because copper sheets have a higher shielding efficiency against magnetic fields.

[0039] To improve the load-bearing stiffness and deformation resistance of the product, in some embodiments, multiple composite material reinforcing ribs are provided on the side of the core material closest to the outer skin of the separator.

[0040] Preferably, the multiple composite material reinforcing ribs are arranged in a grid pattern; each reinforcing rib has a width of 40mm and a thickness of 8.3-31mm.

[0041] Preferably, the width of the first annular gap is 5-8 mm.

[0042] A second aspect of this invention provides a method for preparing a rubber base limiting cover for a sandwich-insulated composite material launch box. The rubber base limiting cover for the sandwich-insulated composite material launch box includes an annular sidewall and a separate body connected to the bottom of the sidewall. The preparation method includes the following steps:

[0043] S1. A first reinforcing material layer is integrally provided on the surface of the male mold used for molding the rubber base limiting cover of the composite material launch box, and the first reinforcing material layer is impregnated with resin.

[0044] S2. The core material and sidewall core material of the separated body are placed on the first reinforcing material layer impregnated with resin;

[0045] S3. The first reinforcing material layer is cut at the junction of the sidewall and the separator, leaving a gap, to divide it into the inner skin of the sidewall and the inner skin of the separator; in the area between the core material of the separator and the core material of the sidewall, an annular release cloth layer, multiple metal sheets, and an annular second reinforcing material layer are arranged in sequence, and the second reinforcing material layer is impregnated with resin; the release cloth layer is located on the outside of the inner skin of the separator and is bonded to the core material of the separator; the second reinforcing material layer is located on the outside of the inner skin of the sidewall, and multiple metal sheets are arranged at intervals along the circumferential direction of the reinforcing material layer;

[0046] S4. A third reinforcing material layer of the outer skin of the launch box rubber base limiting cover is provided on the outside of the core material of the separated body and the side wall core material, and the third reinforcing material layer is impregnated with resin;

[0047] S5. Join the male mold and female mold together and then cure them. Then, process and break the outer skin of the launch box rubber base limiting cover at the junction of the side wall and the separator, dividing it into the side wall outer skin and the separator outer skin. Fill the space between the side wall outer skin and the separator outer skin with a heat-resistant coating. After curing, the sandwich thermal insulation composite material launch box rubber base limiting cover is obtained.

[0048] In some embodiments, a release agent is applied to the surface of the male mold prior to step S1. Preferably, the release agent is applied three times.

[0049] In some implementations, the first reinforcing material layer in step S1 is a carbon fiber material layer.

[0050] In some embodiments, step S1 specifically includes: firstly, laying a layer of carbon fiber surface felt on the surface of the male mold used for molding the rubber base limiting cover of the composite material launch box, then laying the cut carbon fiber multiaxial cloth on the surface of the male mold in sequence, then laying a layer of aerogel felt and a layer of alkali-free untwisted fiber square cloth in sequence, and finally pasting carbon fiber fabric circumferentially on the side wall position and impregnating the above-mentioned fiber fabric with resin.

[0051] Preferably, the carbon fiber multiaxial fabric is laid in a cyclic pattern at an angle of [0 / 90 / 45 / -45]s.

[0052] In some implementations, to avoid air trapped between fiber layers during installation, a plastic scraper is used to press the carbon fiber fabric firmly while it is being installed.

[0053] In some embodiments, the specific arrangement of the release cloth layer, multiple metal sheets, and annular second reinforcing material layer can vary. One approach is to first attach the release cloth layer to one side of the core material, then place the second reinforcing material layer on one side of the sidewall core material, and finally place multiple metal sheets between the release cloth layer and the second reinforcing material layer. Another approach is to attach the release cloth layer to one side of the core material, then place the metal sheets on top of the release cloth layer at selected positions, and then insert the second reinforcing material layer. Yet another approach is to stack the release cloth layer, metal sheets, and second reinforcing material layer, and then insert the entire assembly between the core material and the sidewall core material.

[0054] In some embodiments, the method for setting the second reinforcing material layer specifically involves circumferentially wrapping multiple layers of seam-seam felt strips between the separated core material and the sidewall core material.

[0055] In some embodiments, before step S4, a reinforcing rib groove is processed on the outer surface of the core material of the separated body, and a reinforcing rib reinforcement material is placed in the reinforcing rib groove and impregnated with resin.

[0056] In some embodiments, step S4 specifically includes: laying multiple layers of glass fiber edge felt on the outer side of the core material and the sidewall core material of the separated body, then laying multiple layers of glass fiber edge felt on the sidewall, and finally laying a layer of glass fiber alkali-free untwisted fiber woven fabric, soaking the fabric layer with resin adhesive during laying.

[0057] In some embodiments, in step S5, the outer skin of the launch box rubber base limiting cover is cut off at a height of (205±2) mm at the junction of the side wall and the separation body.

[0058] In some implementations, step S5 is followed by spraying a primer onto the entire outer surface of the product.

[0059] Example 1

[0060] like Figure 3 As shown, the sandwich-insulated composite material launch box rubber base limiting cover of this embodiment has an outer diameter of 1428mm and a total height of 303mm. Figure 2 As shown, the sandwich-insulated composite material launch box rubber base limiting cover includes an annular sidewall 1 and a separation body 2 connected to the bottom of the sidewall 1. That is, the composite material launch box rubber base limiting cover is divided into the sidewall 1 and the separation body 2 by the separation area 7. The vertical distance between the position of the separation area 7 and the lowest point of the product is (90~110) mm.

[0061] like Figure 3As shown, sidewall 1 includes an inner sidewall skin 11, a sidewall core material 12, and an outer sidewall skin 13 arranged sequentially from the inside to the outside. Separator 2 includes an inner separator skin 21, a separator core material 22, and an outer separator skin 23 arranged sequentially from the inside to the outside. The inner sidewall skin 11 and the inner separator skin 21 are made of carbon fiber reinforced epoxy resin composite material with a thickness of 2 ± 0.3 mm. The outer sidewall skin 13 and the outer separator skin 23 are made of glass fiber reinforced epoxy resin composite material with a thickness of 3 mm ± 0.3 mm. The sidewall core material and the separator core material are polyurethane foam with a thickness of 30 mm ± 2 mm (since this product has unequal wall thickness, the core material thickness is a range value).

[0062] An annular composite material layer 3 is provided at one end of the sidewall core material 12 near the separated body 2. The composite material layer 3 is a carbon fiber reinforced epoxy resin-based composite material layer. Figure 4 As shown, eight copper sheets 4 are arranged circumferentially at intervals along the upper end of the composite material layer 3 near the separator 2. The copper sheets are 0.3 mm thick, 50 mm long, and 28 mm wide. The eight copper sheets are evenly spaced and arranged in a cross shape with their center points. An annular polytetrafluoroethylene release cloth layer 5 is provided at the end of the separator core material 22 near the side wall. The adhesive surface of the release cloth layer 5 faces the separator core material 22 and is bonded to the separator core material. The composite material layer 3 and the release cloth layer 5 are connected by resin in the composite material layer. Four composite material reinforcing ribs 8 are provided on the side of the separator core material 22 near the outer skin 23. Each reinforcing rib is 40 mm wide and 8.5 mm thick. The four composite material reinforcing ribs are arranged in a grid shape. An annular gap of 5-8 mm is provided between the inner skin 11 of the side wall and the inner skin 21 of the separation body, and the annular gap is filled with epoxy resin; an annular gap is provided between the outer skin 13 of the side wall and the outer skin 23 of the separation body, and the annular gap is filled with silicone rubber heat-resistant coating 6.

[0063] The preparation method of the rubber base limiting cover of the sandwich-insulated composite material launch box in this embodiment includes the following steps:

[0064] 1. Apply release agent three times to the surface of the male mold used for molding the rubber base limiting cover of the composite material launch box.

[0065] 2. First, lay a layer of carbon fiber surface felt on the entire surface of the male mold, then place the cut carbon fiber multiaxial fabric according to [0 / 90 / 45 / -45]. S The carbon fiber fabric is laid on the surface of the positive mold in sequence at the specified angles. When laying, a plastic scraper is used to press the carbon fiber fabric tightly while laying to avoid air being stored between the fiber layers. Then, a layer of aerogel felt and a layer of EWR200 alkali-free untwisted fiber square cloth are laid in sequence. Finally, two layers of carbon fiber fabric with a width of 300mm and four layers of carbon fiber fabric with a width of 90mm are pasted around the side wall, and the above fiber fabrics are impregnated with epoxy resin.

[0066] 3. Place the prepared polyurethane foam core material and sidewall polyurethane foam core material on the resin-impregnated inner skin fiber fabric.

[0067] 4. Using scissors, cut the inner skin's fibrous fabric along the bottom foam core and sidewall core at the junction of the sidewall and the separator, leaving a 5-8mm gap, thus dividing it into the sidewall inner skin and the separator inner skin. Apply a 30mm wide strip of PTFE release fabric around the side of the separator's urethane foam core. Then, wrap 32 layers of 15mm wide seam-edge felt strips circumferentially between the sidewall polyurethane foam core and the release fabric, placing 8 copper pieces at equal intervals between the seam-edge felt strips and the release fabric. Finally, impregnate the fabric with resin.

[0068] 5. Process reinforcing rib grooves on the outer surface of the core material of the separated body, and place reinforcing rib reinforcement material in the reinforcing rib grooves. Impregnate the reinforcing rib reinforcement material with epoxy resin. Lay three layers of 1270mm wide EMK300 / 600 edge felt on the outer side of the core material of the separated body and the side wall core material. Then, paste three layers of 220mm wide EMK300 / 600 edge felt on the side wall. Finally, lay a layer of EWR200 alkali-free untwisted fiber square cloth. When laying, use a brush to dip into the prepared epoxy resin to impregnate the cloth layer.

[0069] 6. Join the male and female molds together and cure at room temperature. At a height of (197±5) mm from the bottom of the separated body, cut the outer skin radially to a depth of 3-5 mm to ensure that the outer skin is completely cut off. Then fill the cut gap with silicone rubber heat-resistant coating. After the silicone rubber heat-resistant coating has cured, the rubber base limit cover of the sandwich thermal insulation composite material launch box is obtained.

[0070] Testing showed that the rubber base limiting cover of the sandwich-insulated composite material launch box obtained in this embodiment can limit the expansion and deformation of the rubber base under the stored gas. Under a tensile force of 40kN, the separation zone of the product will not be damaged. During operation, under the expansion and deformation of the rubber base, the limiting cover can reliably separate under a tensile force not exceeding 120kN. During high and low temperature tests, its interior can withstand a tensile force of (15-20)kN without structural damage. At -40℃, after 8 hours of insulation, the maximum deformation at the center point and the lowest point of the structure is no greater than 5mm and 2mm, respectively. At 60℃, after 8 hours of insulation, the maximum deformation at the center point and the lowest point of the structure is no greater than 10mm and 5mm, respectively.

[0071] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A sandwich-insulated composite material launch box rubber base limiting cover, characterized in that: The device includes an annular sidewall and a separate body connected to the bottom of the sidewall. The sidewall comprises an inner sidewall skin, a sidewall core material, and an outer sidewall skin arranged and connected sequentially from the inside to the outside. An annular composite material layer is provided and connected to one end of the sidewall core material near the separate body. Multiple metal sheets are spaced circumferentially along the upper end of the composite material layer near the separate body. The separate body comprises an inner separate body skin, a separate body core material, and an outer separate body skin arranged and connected sequentially from the inside to the outside. An annular release fabric layer is provided and connected to one end of the separate body core material near the sidewall, with the adhesive surface of the release fabric layer facing the separate body core material. The composite material layer is connected to the release fabric layer. A first annular gap is provided between the inner sidewall skin and the inner separate body skin, and the first annular gap is filled with resin. A second annular gap is provided between the outer sidewall skin and the outer separate body skin, and the second annular gap is filled with a heat-resistant coating.

2. The sandwich-insulated composite material launch box rubber base limiting cover according to claim 1, characterized in that: Multiple metal sheets are arranged at equal intervals in the circumferential direction of the composite material layer.

3. The sandwich-insulated composite material launch box rubber base limiting cover according to claim 2, characterized in that: The angle between the line connecting the adjacent metal sheet and the center of the composite material layer is 45°.

4. The sandwich-insulated composite material launch box rubber base limiting cover according to claim 1, characterized in that: The core material of the separator has multiple composite material reinforcing ribs on the side near the outer skin of the separator.

5. The rubber base limiting cover for the sandwich-insulated composite material launch box according to claim 1, characterized in that: The inner skin of the sidewall and the inner skin of the separator are made of carbon fiber reinforced resin matrix composite material; the outer skin of the sidewall and the outer skin of the separator are made of glass fiber reinforced resin matrix composite material; the core material of the sidewall and the core material of the separator are polyurethane foam.

6. The sandwich-insulated composite material launch box rubber base limiting cover according to claim 1, characterized in that: The thickness of the inner skin of the sidewall and the inner skin of the separator is 1.7-2.3 mm; the thickness of the outer skin of the sidewall and the outer skin of the separator is 2.7-3.3 mm; and the thickness of the core material of the sidewall and the core material of the separator is 28-32 mm.

7. The sandwich-insulated composite material launch box rubber base limiting cover according to claim 5, characterized in that: The metal sheet has a length of 40-60mm, a width of 25-30mm, and a thickness of 0.1-0.5mm.

8. The sandwich-insulated composite material launch box rubber base limiting cover according to claim 3, characterized in that: The composite material reinforcing ribs are arranged in a grid pattern; each reinforcing rib has a width of 40 mm and a thickness of 8.3-31 mm.

9. A method for preparing a rubber base limiting cover for a sandwich-insulated composite material launch box as described in any one of claims 1-8, characterized in that, The sandwich-insulated composite material launch box rubber base limiting cover includes an annular sidewall and a separate body connected to the bottom of the sidewall; the preparation method includes the following steps: S1. A first reinforcing material layer is integrally provided on the surface of the male mold used for molding the rubber base limiting cover of the composite material launch box, and the first reinforcing material layer is impregnated with resin. S2. The core material and sidewall core material of the separated body are placed on the first reinforcing material layer impregnated with resin; S3. The first reinforcing material layer is cut at the junction of the sidewall and the separated body, leaving a gap, to divide it into an inner skin of the sidewall and an inner skin of the separated body; an annular release cloth layer, multiple metal sheets, and an annular second reinforcing material layer are arranged sequentially in the area between the core material of the separated body and the core material of the sidewall, and the second reinforcing material layer is impregnated with resin; the release cloth layer is located on the outside of the inner skin of the separated body and is bonded to the core material of the separated body; the second reinforcing material layer is located on the outside of the inner skin of the sidewall, and multiple metal sheets are arranged at intervals along the circumferential direction of the second reinforcing material layer; S4. A third reinforcing material layer of the outer skin of the launch box rubber base limiting cover is provided on the outside of the core material of the separated body and the side wall core material, and the third reinforcing material layer is impregnated with resin; S5. The male mold and female mold are joined together and then cured. The outer skin of the launch box rubber base limiting cover is then processed and broken at the junction of the side wall and the separate body, dividing it into the side wall outer skin and the separate body outer skin. A heat-resistant coating is filled between the side wall outer skin and the separate body outer skin. After curing, the sandwich thermal insulation composite material launch box rubber base limiting cover is obtained.

10. The preparation method according to claim 9, characterized in that: The method also includes, prior to step S4, machining a reinforcing rib groove on the outer surface of the core material of the separated body, placing reinforcing rib reinforcement material in the reinforcing rib groove, and impregnating the reinforcing rib reinforcement material with resin.

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