Forming method of heat-proof layer with special-shaped structure

Abstract

The invention discloses a special-shaped structure heat-proof layer forming method, and belongs to the technical field of composite material forming. The forming method of the heat-proof layer with the special-shaped structure comprises the following steps: preparing an edge heat-proof layer blank body; prepreg is prepared, and the prepreg is laid on a sewing tool layer by layer; a plurality of layers of the prepreg close to the outer molded surface are sewn in a penetrating mode and jointed, the jointed follows the hole position of the penetrating sewing, and a large-area heat-proof layer laying layer set is obtained; embedding the edge heat-proof layer blank into the large-area heat-proof layer laying layer group to obtain a heat-proof layer blank; and carrying out pre-pressing and curing treatment on the heat-proof layer blank body to obtain the heat-proof layer with the special-shaped structure.

Description

Technical Field

[0001] The present application belongs to the technical field of composite material molding, and in particular relates to a molding method for a special-shaped heat-resistant layer. Background Art

[0002] Most traditional aircraft are regular cylindrical or conical structures. To meet aerodynamic requirements, high-speed aircraft are designed with special-shaped structures to maintain a high lift-to-drag ratio. Since their flight environment needs to go through a rarefied gas layer and a dense atmosphere, aerodynamic loads and aerodynamic heating are extremely harsh. In a long-term hovering environment, high-temperature erosion causes resin ablation and carbonization inside the heat protection layer. At the same time, under the condition of internal and external temperature changes, the difference in linear expansion between the load-bearing body and the heat protection layer causes internal stress changes, which poses a great challenge to the interlayer strength of the heat protection layer. In order to better adapt to the harsh flight environment, its thermal protection structure is required to have the characteristics of high temperature resistance, ablation resistance, and high interlayer bonding strength.

[0003] In the related art, aircraft with special structures may experience the problem of thermal layer stratification failure under thermal conditions in harsh thermal environments. Summary of the invention

[0004] The present application aims to at least to some extent solve the technical problem of thermal barrier layer delamination failure in the related art. To this end, the present application provides a method for forming a thermal barrier layer with a special-shaped structure.

[0005] The present application provides a method for forming a heat-resistant layer with a special-shaped structure, comprising:

[0006] Prepare the edge heat protection layer embryo;

[0007] Preparing prepreg and laying the prepreg layer by layer on the sewing tool;

[0008] Through-stitching and grouting several layers of the prepreg close to the outer surface, wherein the grouting follows the hole positions of the through-stitching, to obtain a large-area heat-proof layer laying layer group;

[0009] The edge heat protection layer embryo is embedded in the large-area heat protection layer laying layer group to obtain the heat protection layer embryo;

[0010] The heat protection layer embryo is subjected to pre-pressing and curing treatment to obtain the heat protection layer with special structure.

[0011] In some embodiments, the pre-pressing and curing the heat protection layer embryo to obtain the heat protection layer with a special-shaped structure comprises:

[0012] Performing a first pre-compression treatment on the heat protection layer embryo body to obtain a pre-compacted heat protection layer embryo body;

[0013] Transfer the pre-compacted heat protection layer embryo to the curing tooling;

[0014] Laying a technical skin on the outer surface of the pre-compacted heat protection layer embryo body and sewing the technical skin and the pre-compacted heat protection layer embryo body together to obtain the pre-compacted heat protection layer embryo body assembly;

[0015] Performing a second pre-compression treatment on the pre-compacted heat protection layer embryo body component to obtain a secondary pre-compacted heat protection layer embryo body component;

[0016] The secondary pre-compacted heat protection layer embryonic body assembly is cured and the process skin is cleaned to obtain a special-shaped heat protection layer.

[0017] In some embodiments, transferring the pre-compacted heat protection layer embryo to the curing tool comprises:

[0018] Sleeve the transfer tooling onto the pre-compacted heat-proof layer embryo body;

[0019] Fixedly connecting the transfer tool to the suturing tool;

[0020] Sewing the pre-compacted heat protection layer embryo onto the transfer tool by means of the sewing tool;

[0021] Transferring the suturing tool to a disassembly platform, and disassembling the suturing tool;

[0022] Transferring the transfer tool so that the pre-compacted heat protection layer embryo body is mounted on the curing tool;

[0023] Disassemble the transfer tooling.

[0024] In some embodiments, the technical skin includes a plurality of first technical skins and a plurality of second technical skins;

[0025] The step of laying the technical skin on the outer surface of the pre-compacted heat protection layer embryo includes: laying the first technical skin and leaving a gap of 30 mm to 40 mm between two adjacent first technical skins; and laying the second technical skin in the gap.

[0026] In some embodiments, the thickness of the first process skin is 1 mm to 3 mm, the number of the first process skins is 8 to 10, the thickness of the second process skin is 0.2 mm to 0.6 mm, and the width of the second process skin is 50 mm to 60 mm.

[0027] In some embodiments, the secondary pre-compacted heat protection layer embryo assembly includes the technical skin and the secondary pre-compacted heat protection layer embryo, and the molding method also includes: after the second pre-compacting treatment, removing the technical skin on the secondary pre-compacted heat protection layer embryo assembly, trimming the secondary pre-compacted heat protection layer embryo, and after trimming, laying the technical skin on the outer surface of the secondary pre-compacted heat protection layer embryo and sewing the technical skin and the secondary pre-compacted heat protection layer embryo together to form the secondary pre-compacted heat protection layer embryo assembly.

[0028] In some embodiments, the pre-pressing temperature of the first pre-pressing treatment is 30° C. to 80° C., and the pre-compacted heat-protection layer embryo body is further trimmed after the first pre-pressing treatment.

[0029] In some embodiments, the pre-pressing temperature of the second pre-pressing treatment is 50° C. to 80° C., and the pressure of the second pre-pressing treatment includes vacuum pressure and 0.1 MPa to 0.5 MPa external pressure.

[0030] In some embodiments, the row span of the through-stitching stitch length is 10 mm to 50 mm, and the column span is also 10 mm to 50 mm.

[0031] In some embodiments, the curing treatment is performed by step temperature, and when the curing temperature is 80° C. to 100° C., the temperature is kept for 6 h to 8 h, and when the curing temperature is 110° C. to 130° C., the temperature is kept for 3 h to 4 h.

[0032] The present invention has at least the following beneficial effects:

[0033] The forming method of the special-shaped structure heat-proof layer of the present invention performs through-stitching and grouting on several layers of prepreg close to the outer surface, and the grouting uses the hole positions of the through-stitching, thereby improving the interlayer connection effect of the heat-proof layer. The grouting uses the hole positions of the through-stitching, and no new hole positions are added, thereby reducing the damage to the fibers during the suturing process. It has been verified by experiments that after the through-stitching and grouting are added to the special-shaped structure heat-proof layer, the interlayer shear strength of the heat-proof layer is increased by about 60% at 300°C compared with that of the non-stitched layer. The interlayer connection performance of the special-shaped structure heat-proof layer processed by the forming method of the special-shaped structure heat-proof layer of the present invention is good, thereby reducing the risk of delamination failure of the heat-proof layer of the special-shaped structure under thermal conditions in a harsh thermal environment.

[0034] The special-shaped structure heat-proof layer includes two parts: a large-area heat-proof layer and an edge heat-proof layer. The thickness of each part of the large-area heat-proof layer is uniform, and the thickness of the edge heat-proof layer is uneven, presenting a form of thick end and thin end. The special-shaped structure heat-proof layer forming method of the present invention clarifies the processing sequence of the special-shaped structure heat-proof layer, firstly processes the edge heat-proof layer embryo, and then forms a large-area heat-proof layer laying layer group by laying prepreg, and buries the edge heat-proof layer embryo into the large-area heat-proof layer laying layer group, so that the large-area heat-proof layer laying layer group and the edge heat-proof layer embryo are synchronously cured to form a whole, and then the special-shaped structure heat-proof layer is obtained. According to the special-shaped structure heat-proof layer forming method provided by the present invention, the processing difficulty of the heat-proof layer can be simplified and the structural strength of the heat-proof layer can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic cross-sectional view of the first end and the second end of the special-shaped heat protection layer in one or more embodiments of the present application is shown.

[0037] Figure 2 A schematic diagram of the structure of a special-shaped heat protection layer in one or more embodiments of the present application is shown.

[0038] Figure 3 A flow chart of a method for forming a heat-resistant layer with a special-shaped structure in one or more embodiments of the present application is shown.

[0039] Reference numerals: 1 - first end, 2 - second end, 1.1 - upper part, 1.2 - lower part, 1.21 - first straight side, 1.22 - second straight side, 1.23 - curved side. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that all directional indications in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0044] Most traditional aircraft are relatively regular shapes such as cylindrical or conical structures. In order to meet aerodynamic requirements, the appearance of high-speed aircraft is designed as a special-shaped structure to maintain a high lift-to-drag ratio. Because its flight environment needs to go through a thin gas layer and a dense atmosphere, the aerodynamic load and aerodynamic heating are extremely harsh. In a long-term hovering environment, high-temperature erosion causes resin ablation and carbonization inside the heat protection layer. At the same time, under the condition of internal and external temperature changes, the difference in linear expansion between the load-bearing body and the heat protection layer causes internal stress changes, which poses a great test to the interlayer strength of the heat protection layer. In order to better adapt to the harsh flight environment, its thermal protection structure is required to have the characteristics of high temperature resistance, ablation resistance, and high interlayer bonding strength.

[0045] The inventors have analyzed and found that in the related art, aircraft with special structures may fail due to delamination of the heat protection layer under thermal conditions in a harsh thermal environment due to poor interlayer connection of the heat protection layer itself.

[0046] In the related art, the heat protection layer of aircraft with special structures has the technical problem of delamination failure under the thermal conditions of harsh thermal environment. The embodiment of the present application provides a method for forming a heat protection layer with special structures, which can at least solve the technical problem of delamination failure of the heat protection layer to a certain extent.

[0047] In some embodiments of the present application, the following special-shaped heat-proof layer is formed by the special-shaped heat-proof layer forming method:

[0048] like Figure 1 and Figure 2As shown, the special-shaped heat-proof layer comprises a first end 1 and a second end 2 opposite to each other, and the first end 1 and the second end 2 are connected by a variable cone surface. The cross section of the second end 2 of the special-shaped heat-proof layer is circular, the cross section of the upper part 1.1 of the first end 1 of the special-shaped heat-proof layer is in the shape of a Chinese character "J", and the cross section of the lower part 1.2 of the first end 1 comprises a first straight edge 1.21, a second straight edge 1.22 and a curved edge 1.23, one end of the first straight edge 1.21 and one end of the second straight edge 1.22 are respectively connected to the two ends of the Chinese character "J", and the first straight edge 1.21 and the second straight edge 1.22 are parallel to the center line of the Chinese character "J", and the other end of the first straight edge 1.21 and the other end of the second straight edge 1.22 are connected by the curved edge 1.23, and the curved edge 1.23 is arc-shaped, and the arc is arranged away from the middle of the Chinese character "J".

[0049] like Figure 2 As shown, the special-shaped heat protection layer consists of two edge heat protection layers ( Figure 2 The heat protection layer is composed of a large area heat protection layer (the area with the middle dashed line) and a large area heat protection layer (all areas except the edge heat protection layer are large area heat protection layers). The thickness of the large area heat protection layer is relatively uniform, the edge heat protection layer is arranged close to the first end, the thickness of the edge heat protection layer is uneven, one end is thick and the other end is thin, the maximum thickness of the edge heat protection layer is 40mm to 60mm, and the minimum thickness is only 0.5mm. The special-shaped heat protection layer has the characteristics of small acute angles, R angles, and bevels. The special-shaped heat protection layer is a thin-walled special-shaped structure with poor rigidity. The thickness of the special-shaped heat protection layer is not uniform at different places. Under the multi-interface structure, the rigidity of each part is inconsistent.

[0050] It should be noted that the method for forming a special-shaped heat-proof layer provided by the present invention can be used to form the above-mentioned special-shaped heat-proof layer, and of course it can also be used to form other special-shaped heat-proof layers, for example, the method can be used to form the special-shaped heat-proof layer disclosed in Patent Publication No. CN116372506A. Figure 1 The disclosed special-shaped structure may also be the one disclosed in patent publication number CN111196048B. Figure 2 The disclosed special-shaped structures and the like are not limited in this application.

[0051] The following introduces the forming method of special-shaped heat protection layer, such as Figure 3 As shown, the method for forming a special-shaped structure heat protection layer includes steps S100, S200, S300, S400 and S500.

[0052] S100, preparing the embryo of the edge heat protection layer.

[0053] The maximum thickness of the edge heat protection layer is 40mm to 60mm, and the minimum thickness is only 0.5mm. Its structure has the characteristics of small acute angles, R angles, bevels, etc. In order to ensure the appearance quality, the edge heat protection layer embryo can be prepared by a molding process. The prepreg of the edge heat protection layer embryo includes mixed fibers, air-energy fillers and resins. The mixed fibers include two or three of quartz fibers, carbon fibers or high-silica fibers, the air-energy fillers are one or two of hollow microbeads or boron carbides, and the resin includes one or more of barium phenolic formaldehyde, aminophenolic formaldehyde or modified phenolic formaldehyde. Specifically, the prepreg of the edge heat protection layer embryo is added to a mold with the same shape and size as the edge heat protection layer, and then the mold is pre-pressed and demolded to obtain the edge heat protection layer embryo.

[0054] S200, prepare prepreg and lay the prepreg layer by layer on the sewing tooling.

[0055] The prepreg is used to form a large area heat protection layer. The thickness of the prepreg is 0.5mm to 2.5mm. The prepreg is a 2.5D woven fabric prepreg. The fiber of the prepreg is quartz fiber. The type of quartz fiber can be B type, C type or D type. The resin of the prepreg is barium phenolic resin or boron phenolic resin.

[0056] The outer profile of the sewing tool is the same as the inner profile of the heat protection layer. The sewing tool can automatically sew the prepreg. The shape of the sewing tool is related to the shape of the heat protection layer. The structure of the sewing tool is diverse and is not limited in this application. Before using the sewing tool, the sewing tool can be cleaned with alcohol or acetone, and the surface of the sewing tool can be covered with anti-sticking cloth for protection to prevent the prepreg from adhering to the surface of the sewing tool.

[0057] S300, several layers of prepreg close to the outer surface are sewn through and pointed, and the points are pointed along the holes of the sewn through to obtain a large-area heat-proof layer laying layer group.

[0058] It should be noted that the large-area heat protection layer laying layer group includes multiple prepreg laying layers, and each layer of the large-area heat protection layer laying layer group is formed by splicing multiple prepregs. Through stitching is to sew together several layers of prepreg laying layers close to the outer surface, so that the connection of several layers of prepreg laying layers close to the outer surface is strengthened. Pointing is to sew two adjacent prepregs in the same prepreg laying layer together, so that multiple prepregs in the same prepreg laying layer form a whole through pointing, so that the connection of multiple prepregs in the same prepreg laying layer is strengthened. Both through stitching and pointing can be achieved by sewing tooling.

[0059] The layers close to the outer surface can be the first layer and the second layer from the outside to the inside, or the first layer, the second layer and the third layer from the outside to the inside, or the first layer, the second layer, the third layer and the fourth layer from the outside to the inside. The specific number of layers is related to the total number of layers of the large-area heat-proof layer laying layer group, and can be designed according to the adaptability of the user. In some embodiments, the first layer and the second layer from the outside to the inside are through-stitched, and the first layer and the second layer are both pointed.

[0060] It has been verified through experiments that the row span of the stitch length for through-sewing is preferably 10 mm to 50 mm, and the column span is also preferably 10 mm to 50 mm.

[0061] In harsh thermal environment conditions, after the resin is carbonized and decomposed at high temperature, the interlayer adhesion of the heat-proof layer itself is weakened, and there is a risk of delamination. The molding method of the special-shaped heat-proof layer of the present invention performs through-stitching and grouting on several layers of prepreg close to the outer surface, and the grouting uses the holes of the through-stitching, which improves the interlayer connection effect of the heat-proof layer. The grouting uses the holes of the through-stitching and no new holes are added, which reduces the damage to the fibers during the suturing process. It has been verified by experiments that after the heat-proof layer is added with through-stitching and grouting, the shear strength between the layers of the heat-proof layer is increased by about 60% at 300°C compared with that of the unstitched layer.

[0062] S400, burying the edge heat protection layer embryo body in the large-area heat protection layer laying layer group to obtain the heat protection layer embryo body.

[0063] At least the edge portion of the edge heat protection layer embryo body is buried between two adjacent prepreg laying layers to obtain the heat protection layer embryo body. It should be noted that the edge heat protection layer embryo body can be buried in the large-area heat protection layer laying layer group during the production process of the large-area heat protection layer laying layer group, and can also be buried in the large-area heat protection layer laying layer group after the large-area heat protection layer laying layer group is completed.

[0064] like Figure 1 and Figure 2 The first end 1 of the special-shaped heat-proof layer shown is the small end, and the second end 2 is the large end. If in step S300 and step S400, the first end 1 is at the top and the second end 2 is at the bottom, that is, the edge heat-proof layer embryo is located at the upper end of the sewing tool, it will cause the edge heat-proof layer embryo to lack support after being buried in the large-area heat-proof layer laying layer group, and it is easy to cause the edge heat-proof layer embryo to slide downward and be misplaced. The outer surface of the sewing tool is consistent with the inner surface of the special-shaped heat-proof layer. Therefore, if the present application is used to prepare Figure 1 and Figure 2 In the case of the special-shaped structure shown, in step S300 and step S400, the small end of the sewing tool is at the bottom and the large end is at the top, so that the edge heat protection layer embryo is located at the lower end of the sewing tool. The lower end of the sewing tool can support the edge heat protection layer embryo to avoid dislocation of the edge heat protection layer embryo to a certain extent.

[0065] S500, pre-pressing and curing the heat protection layer embryo to obtain a heat protection layer with a special structure.

[0066] The heat protection layer embryo is first pre-pressed and then cured. The pre-pressing process helps to compact the prepreg in the mold, so that the resin can be more evenly distributed between the fibers and improve the impregnation effect. After this design, in the subsequent curing process, the resin can more fully infiltrate the fibers and form a stronger interface bonding force.

[0067] Step S500 may include steps S510 , S520 , S530 , S540 , S550 , and S560 .

[0068] S510, performing a first pre-compression treatment on the heat protection layer embryo body to obtain a pre-compacted heat protection layer embryo body.

[0069] The heat protection layer embryo is subjected to the first pre-pressing treatment. Specifically, the heat protection layer embryo can be sealed by a vacuum bag and pre-pressed by vacuum pressure. The pre-pressing temperature of the first pre-pressing is 30℃~80℃. After the pre-pressing is completed, the vacuum bag is opened to trim the wrinkles and depressions on the surface of the pre-pressed heat protection layer embryo.

[0070] S520, transferring the pre-compacted heat protection layer embryo to a curing tool.

[0071] The pre-compacted heat protection layer embryo is transferred to the curing tooling for subsequent curing treatment by the curing tooling.

[0072] Step S520 may include steps S521 , S522 , S523 , S524 , S525 , and S526 .

[0073] S521, set the transfer tooling set outside the pre-compacted heat protection layer embryo body.

[0074] The inner surface of the transfer jig is the same as the outer surface of the heat protection layer, the shape of the transfer jig is related to the shape of the heat protection layer, and the structure of the transfer jig is diverse, which is not limited in this application. Before using the transfer jig, the transfer jig can be cleaned with alcohol or acetone, and an anti-sticking cloth can be laid on the inner surface of the transfer jig for protection to prevent the prepreg from adhering to the inner surface of the transfer jig.

[0075] S522, the transfer tooling is fixedly connected to the suturing tooling.

[0076] After the transfer tool is sleeved on the pre-compacted heat-proof layer embryo body, the transfer tool and the sewing tool are fixed to facilitate step S523. The fixation can be performed by bolt connection or clamping.

[0077] S523, sewing the pre-compacted heat protection layer embryo onto the transfer tool through a sewing tool.

[0078] The pre-compacted heat-proof layer embryo is fixed on the transfer tooling by sewing, so that the pre-compacted heat-proof layer embryo is tied and fixed to the transfer tooling, and the sewing between the pre-compacted heat-proof layer embryo and the transfer tooling is achieved by sewing the tooling. The sewing here can be through-sewing, and the sewing density is 20% to 40% of the through-sewing density in the above step S300, reducing the damage to the strength of the heat-proof layer caused by over-dense sewing, and can meet the fixed connection function.

[0079] S524, transferring the suturing tool to the disassembly platform, and disassembling the suturing tool.

[0080] After the stitching is completed, the stitching tool, the transfer tool and the pre-compacted heat protection layer embryo formed by the transfer tool can be transferred to the disassembly platform, and then the stitching tool is disassembled to separate the stitching tool from the transfer tool.

[0081] S525, transferring the transfer tooling to fit the pre-compacted heat protection layer embryo onto the curing tooling.

[0082] The transfer tooling is used to set the pre-compacted heat-resistant layer embryo body fixed on the transfer tooling outside the curing tooling. Specifically, after the pre-compacted heat-resistant layer embryo body is set on the curing tooling, the transfer tooling can also be fixedly connected with the curing tooling by bolt connection. The downward pressure formed during the tightening of the bolts exerts a certain pressure on the pre-compacted heat-resistant layer embryo body, so that the pre-compacted heat-resistant layer embryo body is set downward in place.

[0083] The outer surface of the curing tooling is the same as the inner surface of the heat protection layer, the shape of the curing tooling is related to the shape of the heat protection layer, and the structure of the curing tooling is diverse, which is not limited in this application.

[0084] like Figure 1 and Figure 2 The first end 1 of the special-shaped heat-proof layer shown is a small end, and the second end 2 is a large end. Figure 1 and Figure 2 When the special-shaped structure shown is shown, when performing step S525, the small end of the curing tool and the transfer tool is at the top and the large end is at the bottom, so as to ensure that the pre-compacted heat-proof layer embryo can be smoothly mounted on the curing tool. Specifically, the transfer tool can be transferred by lifting with a sling. When transferring the transfer tool, that is, when performing step S525, the hook of the sling lifts the small end of the transfer tool so that the large end of the pre-compacted heat-proof layer embryo is at the bottom and the small end is at the top, so that the pre-compacted heat-proof layer embryo can be smoothly mounted on the curing tool.

[0085] S526, dismantle the transfer tooling.

[0086] After the pre-compacted heat-proof layer embryo body is in place, the transfer tooling can be disassembled. Specifically, the suture line between the transfer tooling and the pre-compacted heat-proof layer embryo body is cut to separate the transfer tooling from the pre-compacted heat-proof layer embryo body.

[0087] S530, laying the technical skin on the outer surface of the pre-compacted heat protection layer and sewing the technical skin and the pre-compacted heat protection layer embryo body together to obtain the pre-compacted heat protection layer embryo body assembly.

[0088] The process skin needs to be made in advance. The process skin can be formed by using a prepreg with a thickness of 0.2mm to 0.4mm in a rigid mold with the same outer surface as the special-shaped structure heat protection layer. Considering that the skin still needs a certain rigidity during the pressurization of the heat protection layer to ensure the overall appearance of the heat protection layer, poor rigidity will cause problems such as local overhead and skin breakage. The thickness of the skin is preferably 1mm to 3mm. The pre-compacted heat protection layer embryo assembly includes a pre-compacted heat protection layer embryo and a process skin sewn on the pre-compacted heat protection layer embryo.

[0089] In order to ensure that the skin is more closely fitted to the pre-compacted heat protection layer embryo, the process skin includes multiple first process skins and second process skins. When laying the process skin, the first process skin is laid first, and a gap of 30mm to 40mm is reserved between two adjacent first process skins, and then the second process skin is laid in the gap. The thickness of the first process skin is 1mm to 3mm, the number of first process skins is 8 to 10 pieces, the thickness of the second process skin is 0.2mm to 0.6mm, and the width of the second process skin is 50mm to 60mm. Considering the difference in linear expansion coefficient of metal molds during high temperature process during splicing, the skin at the splicing position will be misaligned and squeezed, which will cause wrinkles and depressions on the surface of the special-shaped heat protection layer. According to the curing temperature difference and the thermal expansion coefficient of the product, it is best to reserve a gap of 30mm to 40mm at the splicing position. However, the contact position between the edge of the first process skin with a larger thickness and the special-shaped heat protection layer will still cause depressions on the surface of the heat protection layer. Therefore, the second process skin with a thickness specification of 0.2mm to 0.6mm is prepared, cut into rectangular strips with a width of 50mm to 60mm, and the second process skin is padded in the reserved gap position of the splicing to ensure the surface quality of the special-shaped heat protection layer. After this design, the maximum apparent convexity or depression of the special-shaped heat protection layer is ≤0.6mm, and the external surface quality is good.

[0090] In the following steps S540 and S550, vacuum pressure and external pressure will be applied to the process skin, and the skin is at risk of movement and displacement. If this problem occurs, it will cause large extrusion wrinkles or indentations on the surface of the special-shaped structure heat protection layer. Through research, it is found that by punching holes (hole diameter Φ≤2mm) at the upper and lower ends of the skin, and then using sutures (which can be organic fiber sutures), and by sewing the skin locally to the pre-compacted heat protection layer embryo by hooking, the stability of the subsequent skin position can be guaranteed, and the external surface quality of the special-shaped structure heat protection layer can be guaranteed.

[0091] S540, performing a second pre-compression treatment on the pre-compacted heat protection layer embryo body component to obtain a secondary pre-compacted heat protection layer embryo body component.

[0092] The pre-compacted heat protection layer embryo and the technical skin thereon are subjected to a second pre-compacting treatment together, and the skin can shape the whole pre-compacted heat protection layer embryo during the second pre-compacting treatment.

[0093] The pre-pressing temperature of the second pre-pressing is 50℃~80℃, and the pressure of the second pre-pressing treatment includes vacuum pressure and 0.1Mpa~0.5Mpa external pressure. That is to say, in addition to the vacuum pressure, the second pre-pressing also adds 0.1Mpa~0.5Mpa external pressure for pre-pressing.

[0094] The secondary pre-compacted heat protection layer embryo assembly includes a secondary pre-compacted heat protection layer embryo and a process skin sewn thereon. In some embodiments, step S550 is further included, after the second pre-compacting treatment (i.e., after step S540), the process skin on the secondary pre-compacted heat protection layer embryo assembly is removed, the secondary pre-compacted heat protection layer embryo is trimmed, and after the trimming, the process skin is laid on the outer surface of the secondary pre-compacted heat protection layer embryo and the process skin is sewn together with the secondary pre-compacted heat protection layer embryo to form a secondary pre-compacted heat protection layer embryo assembly.

[0095] That is to say, after step S540, the process skin is removed from the secondary pre-compacted heat protection layer embryonic body assembly so that the operator can separately clean the secondary pre-compacted heat protection layer embryonic body of the secondary pre-compacted heat protection layer embryonic body assembly to ensure the dimensional accuracy of the special-shaped structure heat protection layer after curing.

[0096] S560, curing the secondary pre-compacted heat protection layer embryonic body assembly and cleaning the process skin to obtain a special-shaped heat protection layer.

[0097] Specifically, a curing treatment is performed first, and then the skin is cleaned after the curing treatment is completed.

[0098] The curing treatment is carried out through a step temperature. When the curing temperature is 80°C ~ 100°C, the temperature is kept for 6h ~ 8h. When the curing temperature is 110°C ~ 130°C, the temperature is kept for 3h ~ 4h.

[0099] In some embodiments, when the curing treatment is performed by step temperature, the temperature of the secondary pre-compacted heat protection layer embryo assembly is gradually increased from room temperature to 80°C~100°C, and after increasing to 80°C~100°C, it is kept warm for 6h~8h; after keeping warm for 6h~8h, the temperature is gradually increased to 110°C~130°C, and increased to 110°C~130°C, and kept warm for 3h~4h; after keeping warm for 3h~4h, the temperature is increased to the set maximum curing temperature, and when the temperature reaches the maximum curing temperature, it is cooled so that the secondary pre-compacted heat protection layer embryo assembly is gradually cooled to room temperature.

[0100] In some embodiments, the maximum curing temperature is 180°C.

[0101] During the curing process, the secondary pre-compacted heat protection layer embryo assembly is also vacuumed, and an external pressure of 0.1Mpa to 0.5Mpa is applied to the secondary pre-compacted heat protection layer embryo assembly. After the curing treatment, the surface process skin, vacuum bag, etc. are removed to obtain a special-shaped structure heat protection layer.

[0102] After obtaining the special-shaped structure heat protection layer, the local glue accumulation of the special-shaped structure heat protection layer can be polished and other treatments can be performed to adjust the dimensional accuracy of the special-shaped structure heat protection layer.

[0103] After the special-shaped heat-proof layer is prepared, the special-shaped heat-proof layer can be installed on the load-bearing body according to the following steps:

[0104] S1000, the set glue is applied on the inner surface of the special-shaped heat-proof layer and the outer surface of the load-bearing body;

[0105] S2000, the special-shaped structure heat-proof layer is mounted outside the load-bearing body, so that the special-shaped structure heat-proof layer is bonded to the load-bearing body.

[0106] The special-shaped structure heat-proof layer is set outside the load-bearing body and left to cure for 72h to 96h. The time taken for the setting process is no more than 30min. The ambient temperature of the setting process is 20℃ to 30℃ and the humidity is 45%RH to 75%RH.

[0107] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0108] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0109] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for forming a special-shaped heat-proof layer, characterized in that: include: Prepare the edge heat protection layer embryo; Preparing prepreg and laying the prepreg layer by layer on the sewing tool; Through-stitching and grouting several layers of the prepreg close to the outer surface, wherein the grouting follows the hole positions of the through-stitching, to obtain a large-area heat-proof layer laying layer group; The edge heat protection layer embryo is buried in the large-area heat protection layer laying layer group to obtain the heat protection layer embryo; The heat protection layer embryo is subjected to pre-pressing and curing treatment to obtain the heat protection layer with special structure.

2. The method for forming a special-shaped structure heat protection layer according to claim 1, characterized in that: The pre-pressing and curing treatment of the heat protection layer embryo to obtain the heat protection layer with a special-shaped structure comprises: Performing a first pre-compression treatment on the heat protection layer embryo body to obtain a pre-compacted heat protection layer embryo body; Transfer the pre-compacted heat protection layer embryo to the curing tooling; Laying a technical skin on the outer surface of the pre-compacted heat protection layer embryo body and sewing the technical skin and the pre-compacted heat protection layer embryo body together to obtain a pre-compacted heat protection layer embryo body assembly; Performing a second pre-compression treatment on the pre-compacted heat protection layer embryo body component to obtain a secondary pre-compacted heat protection layer embryo body component; The secondary pre-compacted heat protection layer embryonic body assembly is cured and the process skin is cleaned to obtain the special-shaped structure heat protection layer.

3. The method for forming a special-shaped structure heat protection layer according to claim 2, characterized in that: The step of transferring the pre-compacted heat-proof layer embryo to the curing tooling comprises: Sleeve the transfer tooling onto the pre-compacted heat-proof layer embryo body; Fixedly connecting the transfer tool to the suturing tool; Sewing the pre-compacted heat protection layer embryo onto the transfer tool by means of the sewing tool; Transferring the suturing tool to a disassembly platform, and disassembling the suturing tool; Transferring the transfer tool so that the pre-compacted heat protection layer embryo body is mounted on the curing tool; Disassemble the transfer tooling.

4. The method for forming a special-shaped structure heat protection layer according to claim 2, characterized in that: The technical skin includes a plurality of first technical skins and a plurality of second technical skins; The step of laying the technical skin on the outer surface of the pre-compacted heat protection layer embryo comprises: laying the first technical skin and leaving a gap of 30 mm to 40 mm between two adjacent pieces of the first technical skin; The second process skin is laid in the gap.

5. The special-shaped structure heat protection layer according to claim 4, characterized in that: The thickness of the first process skin is 1 mm to 3 mm, the number of the first process skins is 8 to 10, the thickness of the second process skin is 0.2 mm to 0.6 mm, and the width of the second process skin is 50 mm to 60 mm.

6. The method for forming a special-shaped heat-proof layer according to claim 2, characterized in that: The secondary pre-compacted heat protection layer embryo assembly includes the technical skin and the secondary pre-compacted heat protection layer embryo, and the molding method also includes: after the second pre-compacting treatment, removing the technical skin on the secondary pre-compacted heat protection layer embryo assembly, trimming the secondary pre-compacted heat protection layer embryo, laying the technical skin on the outer surface of the secondary pre-compacted heat protection layer embryo after trimming, and sewing the technical skin and the secondary pre-compacted heat protection layer embryo together to form the secondary pre-compacted heat protection layer embryo assembly.

7. The method for forming a special-shaped heat-proof layer according to any one of claims 2 to 6, characterized in that: The pre-pressing temperature of the first pre-pressing treatment is 30° C. to 80° C., and the pre-compacted heat-proof layer embryo body is further trimmed after the first pre-pressing treatment.

8. The method for forming a special-shaped structure heat protection layer according to any one of claims 2 to 6, characterized in that: The pre-pressing temperature of the second pre-pressing treatment is 50° C. to 80° C., and the pressure of the second pre-pressing treatment includes vacuum pressure and 0.1 MPa to 0.5 MPa external pressure.

9. The method for forming a special-shaped heat-proof layer according to any one of claims 1 to 6, characterized in that: The row span of the stitch length of the through-stitching is 10 mm to 50 mm, and the column span is also 10 mm to 50 mm.

10. The method for forming a special-shaped heat-proof layer according to any one of claims 1 to 6, characterized in that: The curing treatment is carried out by step temperature. When the curing temperature is 80° C. to 100° C., the temperature is kept for 6 h to 8 h. When the curing temperature is 110° C. to 130° C., the temperature is kept for 3 h to 4 h.

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