A repairing method for R angle defect of composite material engine shell heat insulation structure

Abstract

The application discloses a kind of composite material engine shell heat insulation structure R angle defect repair methods, comprising the following steps S1, using mould pressing mode to prepare two R angle preforms;S2, the two R angle preforms obtained in S1 are cut and polished;S3, the R angle preform after cutting and polishing is tried on with the R angle defect position to be repaired;S4, the R angle preform used for repair and the shell to be repaired are dried;S5, using adhesive R angle preform is bonded in the R angle defect position to be repaired;S6, the composite material engine shell with R angle preform is bonded is transferred to hot pressing jar and is heated and pressurized curing.The composite material engine shell heat insulation structure R angle defect repair method disclosed in the application is repaired by using mould pressing preform, reduces the bonding interface involved in the repair process, reduces the bonding risk, reduces the number of hot-pressing curing, greatly shortens the pressurized curing time in the shell repair process.

Description

Technical Field

[0001] This invention belongs to the field of repair technology for defects in the thermal insulation structure of aerospace composite engine casings, specifically relating to a method for repairing R-angle defects in the thermal insulation structure of composite engine casings. Background Technology

[0002] With the rapid development of aerospace technology, composite material engine casings have gradually become an important research direction for aerospace launch vehicle technology and strategic and tactical missile power plants. The heat insulation structure of composite material engine casings is a structure used to insulate, prevent ablation, and protect against erosion of composite material engine casings. It is an important component of composite material engine casings.

[0003] As shown in the attached diagram of the instruction manual. Figure 4 It is known that the common composite material engine casing insulation structure generally consists of several parts: front end heat insulation layer 1, rear end heat insulation layer 2, and cylindrical section heat insulation layer 3. During the molding and curing process of the insulation structure along with the composite material engine casing, defects often appear at the opening R-corner of the front end heat insulation layer 1 or the rear end heat insulation layer 2. When defects appear at the opening R-corner of the end in the insulation structure, it will affect the normal operation of the engine casing. In order to ensure the protective effect of the insulation structure, it is necessary to repair the opening R-corner of the end in the insulation structure.

[0004] In existing technologies, the method of applying an insulation layer and applying vacuum bag pressure is commonly used to repair the R-angle of the end cap opening of the insulation structure of the composite engine housing. When this method is used to repair the R-angle of the insulation structure, bridging and debonding defects will occur in the insulation structure at the repaired R-angle, and the end cap opening R-angle of the composite engine housing insulation structure cannot be effectively repaired.

[0005] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to provide a method for repairing R-corner defects in the thermal insulation structure of a composite engine casing, which can efficiently repair R-corner defects in the thermal insulation structure of a composite engine casing.

[0007] To achieve the above objectives, the technical solution provided by a specific embodiment of the present invention is as follows: A method for repairing R-corner defects in the thermal insulation structure of a composite engine casing includes the following steps: S1. Two R-angle preforms are prepared by molding. S2. Cut and grind the two R-angle prefabricated parts obtained in S1. S3. Test fit the pre-made R-corner component after cutting and grinding with the R-corner defect location to be repaired; S4. Dry the precast R-angle parts used for repair and the shell to be repaired; S5. Use adhesive to bond the R-corner prefabricated part to the R-corner defect to be repaired; S6. Transfer the composite engine housing with the R-angle prefabricated parts bonded to the autoclave for heating and pressurization curing; S7. Grind the repaired area to create a smooth transition and then conduct a quality inspection.

[0008] In one or more embodiments of the present invention, the molding method in S1 includes the following steps: S11. Mold cleaning: Use solvent to clean the surface of the molding die and spray a Teflon coating on the mold surface. S12, Filler: Cut the uncured heat insulation rubber sheet into the required size and lay the cut heat insulation rubber sheet into the molding die in sequence. S13. Compression molding: The compression mold is closed, and a thermocouple is installed inside the compression mold. The closed compression mold is then transferred to a press for heating and pressurization vulcanization molding. S14. Demolding inspection: Demold the R-angle preform after vulcanization and perform appearance, dimensional and damage inspection.

[0009] In one or more embodiments of the present invention, the heat-insulating rubber sheet is a nitrile rubber sheet, and the weight of the nitrile rubber sheet is 10% to 15% more than the theoretical weight of the R-angle preform.

[0010] In one or more embodiments of the present invention, the temperature of the thermocouple in S13 is ≤150°C, the heating and cooling rate of the thermocouple does not exceed 2°C / min, and the pressure of the press is ≤150 tons.

[0011] In one or more embodiments of the present invention, step S2 specifically includes the following steps: S21. Cut a whole circular R-corner precast part into two halves along a 30° angle, and number them 1# and 2# respectively. At the same time, cut another whole circular R-corner precast part into a R-corner precast part with a length of not less than 150mm along a 30° angle, and number it 3#. S22. Grind the cutting positions of #1 and #2 so that the cutting positions of the R-angle precast parts of #1 and #2 can overlap by 15~20mm.

[0012] In one or more embodiments of the present invention, step S3 specifically includes the following steps: S31. Roughen the bonding surfaces of the No. 1, No. 2 and No. 3 R-angle preforms, the bonding surfaces of the 0.5mm calcined rubber sheet, and the defective locations of the shell insulation structure by grinding, and clean the grinding surfaces with solvent. S32. Fix a 0.5mm thick sheet of unadhesive rubber to the defect location of the shell insulation structure, and mark the position of the rubber sheet by drawing a line at the defect location of the shell insulation structure. S33. Place the #1 R corner preform at the defect location of the shell insulation structure where the rubber sheet has been applied for trial fitting, and observe the fit between the #1 R corner preform and the defect location of the shell insulation structure from the side. Mark the trial fitting position of the #1 R corner preform at the defect location of the shell insulation structure. S34. Similarly, trial fitting of the 2#R corner prefabricated component is carried out, and the trial fitting position of the 2#R corner prefabricated component is marked by drawing a line at the defect location of the shell insulation structure. S35. Trial fitting of the 3#R-angle precast component. During the trial fitting process, fix the 1#R-angle precast component and the 2#R-angle precast component at the defect position of the shell insulation structure, and grind both ends of the 3#R-angle precast component so that the cut of the 3#R-angle precast component can overlap with the 1#R-angle precast component and the 2#R-angle precast component by 15~20mm, so that the 1#R-angle precast component, the 2#R-angle precast component and the 3#R-angle precast component can be spliced ​​into a spliced ​​whole round R-angle precast component; S36. After the trial fitting is completed, mark the trial fitting position of the spliced ​​round R-corner prefabricated part at the defect location of the shell insulation structure.

[0013] In one or more embodiments of the present invention, step S4 specifically includes the following steps: S41. Clean the prefabricated 1#, 2#, and 3# R-angle components, 0.5mm calcined rubber sheet, and the defective areas of the shell insulation structure. S42. Place the cleaned #1, #2, and #3 R-angle preforms, 0.5mm calcined rubber sheets, and the defective locations of the shell insulation structure into an oven and pre-dry them at 80°C.

[0014] In one or more embodiments of the present invention, step S5 specifically includes the following steps: S51. Prepare the adhesive according to the adhesive mixing ratio; S52. Lay a 0.5mm thick sheet of calcined rubber around the defect in the insulation structure of the shell, and apply adhesive to the calcined rubber sheet and the defect in the insulation structure of the shell. S53. Use a vacuum bag to cold press the calcined rubber sheet. After cold pressing, grind the edges of the calcined rubber sheet to transition. S54. Place the #1 R corner preform again at the defect location of the shell insulation structure where the cured rubber sheet has been laid, and observe the fit between the #1 R corner preform and the defect location of the shell insulation structure to determine if the #1 R corner preform is suitable for trial fitting. S55. Trial fit the precast components of R-angle 2# and 3# again using the above method, and confirm that the cuts of the precast components of R-angle 1#, 2# and 3# can overlap each other by 15~20mm, and that the precast components of R-angle 1#, 2# and 3# can be spliced ​​into a complete circle. S56. Lay the #1, #2, and #3 R-angle prefabricated parts sequentially to the marked positions of the defects in the shell insulation structure. Apply adhesive to the bonding surfaces of the #1, #2, and #3 R-angle prefabricated parts during the laying process. S57. Lay a 0.5mm thick sheet of calcined rubber over the entire repair area. The area covered by the sheet should be 10-15mm larger than the surrounding area of ​​the repair area. Apply adhesive to the bonding surface of the calcined rubber sheet during the laying process. S58. Vacuum bags are used to pressurize the repair area.

[0015] Preferably, the adhesive is a room-temperature vulcanizing adhesive.

[0016] Preferably, the cold pressing conditions in S53 are a vacuum degree of not more than -90 kPa and a cold pressing time of not less than 2 hours.

[0017] In one or more embodiments of the present invention, step S6 specifically includes the following steps: S61. Transfer the bonded shell into the autoclave. S62. Check the airtightness of the vacuum bag; S63. The bonded shell is cured by heating and pressurizing.

[0018] Preferably, the airtightness requirement of S62 is a vacuum degree not greater than -95 kPa.

[0019] In one or more embodiments of the present invention, step S7 specifically includes the following steps: S71. After curing, remove the vacuum bag-like auxiliary materials from the shell repair area; S72. Smooth the repaired area on the casing; S73. Perform dimensional, visual, and non-destructive testing on the repaired area of ​​the casing.

[0020] Compared with the prior art, the method for repairing R-corner defects in the thermal insulation structure of composite engine casing disclosed in this invention ensures the bonding quality at the repair site by using a hot autoclave pressurization process, and avoids defects such as bridging and debonding during the repair process. By using heat-insulating rubber PVC sheets for repair, the shell does not need to be locally reinforced with high-temperature vulcanized raw material sheets, thus avoiding the adverse effects of localized high temperatures on the shell. By using molded prefabricated parts for repair, the number of bonding interfaces involved in the repair process is reduced, the bonding risk is lowered, the number of hot-press curing cycles is reduced, and the pressure curing time in the shell repair process is greatly shortened. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is an overall flowchart of a method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to an embodiment of the present invention; Figure 2 This is a partial flowchart of a method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to an embodiment of the present invention; Figure 3 This is another part of the flowchart of the method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to one embodiment of the present invention; Figure 4 This is a schematic diagram of the thermal insulation structure of a composite material engine casing in the prior art; Figure 5 for Figure 4 Schematic diagram of the structure at point A in the middle; Figure 6 This is a schematic diagram of the cutting position port of the R-angle prefabricated component in one embodiment of the present invention; Figure 7 This is a schematic diagram of the splicing state of the R-corner prefabricated component in one embodiment of the present invention.

[0023] Explanation of key figure labels: 1-Front end heat insulation layer, 2-Rear end heat insulation layer, 3-Cylindrical section heat insulation layer, 4-Spliced ​​precast component with rounded corner. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0025] like Figures 1 to 7 As shown, a method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to an embodiment of the present invention includes the following steps: preparing two R-angle preforms by molding.

[0026] like Figure 2 As shown, the molding process includes the following steps: S11, mold cleaning: clean the surface of the molding mold with solvent and spray a Teflon coating on the mold surface; S12, filling: cut the uncured insulating rubber sheet to the required size and lay the cut insulating rubber sheet into the molding mold in sequence; S13, molding: close the molding mold and install a thermocouple in the molding mold. Transfer the closed molding mold to a press for heating and pressurizing vulcanization. The temperature of the thermocouple is ≤150℃, the heating and cooling rate of the thermocouple does not exceed 2℃ / min, and the pressure of the press is ≤150 tons. Depressurization and venting operations are required during the pressurization process; S14, demolding and inspection: demold the R-angle preform after vulcanization and perform appearance, dimensional, and damage inspection.

[0027] Preferably, the insulating rubber sheet is a nitrile rubber sheet, and the weight of the nitrile rubber sheet is 10% to 15% more than the theoretical weight of the R-angle preform.

[0028] like Figure 1 As shown, the two R-angle preforms obtained in S1 are cut and polished.

[0029] like Figure 2 As shown, the specific steps include: S21, cutting a whole round R-corner precast part into two halves along a 30° angle, numbering them 1# and 2# respectively; at the same time, cutting another whole round R-corner precast part into a R-corner precast part with a length of not less than 150mm along a 30° angle, and numbering it 3#; S22, grinding the cut positions of 1# and 2# so that the cut positions of 1# and 2# R-corner precast parts can overlap by 15~20mm.

[0030] like Figure 1 As shown, the prefabricated R-corner component after cutting and grinding is tested against the R-corner defect location to be repaired.

[0031] like Figure 2As shown, the specific steps include: S31, roughening the bonding surfaces of the #1, #2, and #3 R-angle preforms, the bonding surfaces of the 0.5mm PVC-U rubber sheet, and the defect locations of the shell insulation structure by sanding, and cleaning the sanded surfaces with solvent; S32, fixing a layer of 0.5mm PVC-U rubber sheet without adhesive to the defect location of the shell insulation structure, and marking the position of the PVC-U rubber sheet at the defect location of the shell insulation structure; S33, placing the #1 R-angle preform on the defect location of the shell insulation structure with the PVC-U rubber sheet attached for trial fitting, and observing the fit between the #1 R-angle preform and the defect location of the shell insulation structure from the side, and marking the trial fitting position of the #1 R-angle preform at the defect location of the shell insulation structure. S34. Similarly, perform a trial fit on the 2#R-angle precast component and mark the trial fit position of the 2#R-angle precast component at the location of the defect in the shell insulation structure. S35. Perform a trial fit on the 3#R-angle precast component. During the trial fit, fix the 1#R-angle precast component and the 2#R-angle precast component at the location of the defect in the shell insulation structure, and grind both ends of the 3#R-angle precast component so that the cut edges of the 3#R-angle precast component can overlap by 15~20mm with the 1#R-angle precast component and the 2#R-angle precast component, so that the 1#R-angle precast component, the 2#R-angle precast component and the 3#R-angle precast component can be spliced ​​into a spliced ​​whole round R-angle precast component 4. S36. After the trial fit is completed, mark the trial fit position of the spliced ​​whole round R-angle precast component 4 at the location of the defect in the shell insulation structure.

[0032] like Figure 1 As shown, the R-angle prefabricated part used for repair and the shell to be repaired are dried.

[0033] like Figure 2 As shown, the specific steps include: S41, cleaning the pre-fitted #1, #2, and #3 R-angle preforms, 0.5mm calcined rubber sheet, and the defective areas of the shell insulation structure; S42, placing the cleaned #1, #2, and #3 R-angle preforms, 0.5mm calcined rubber sheet, and the defective areas of the shell insulation structure into an oven and pre-drying at 80℃ for 2 hours.

[0034] like Figure 1 As shown, the R-corner prefabricated part is bonded to the R-corner defect to be repaired using adhesive.

[0035] like Figure 3As shown, the specific steps include: S51, preparing the adhesive according to the adhesive ratio; S52, laying a 0.5mm thick sheet of calcined rubber around the entire perimeter of the shell insulation structure defect, and applying adhesive to the calcined rubber sheet and the shell insulation structure defect; S53, cold-pressing the calcined rubber sheet using a vacuum bag, and after cold pressing, sanding the edges of the laid calcined rubber sheet for transition. The cold pressing conditions are a vacuum degree not exceeding -90KPa and a cold pressing time of not less than 2 hours; S54, placing the #1 R-angle precast component again on the shell insulation structure defect where the calcined rubber sheet has been laid for trial fitting, observing the fit between the #1 R-angle precast component and the shell insulation structure defect, and confirming that the #1 R-angle precast component is suitable for trial fitting; S5 5. Trial fit the #2 and #3 R-angle prefabricated parts again using the above method, and confirm that the cut edges of the #1, #2, and #3 R-angle prefabricated parts can overlap by 15-20mm, and that the #1, #2, and #3 R-angle prefabricated parts can be spliced ​​into a complete circle; S56. Lay the #1, #2, and #3 R-angle prefabricated parts sequentially to the marked positions of the defects in the shell insulation structure, and apply adhesive to the bonding surfaces of the #1, #2, and #3 R-angle prefabricated parts during the laying process; S57. Lay a layer of 0.5mm thick PVC-U rubber sheet to cover the entire repair area, with the laying area being 10-15mm larger than the overall perimeter of the repair area, and apply adhesive to the bonding surfaces of the PVC-U rubber sheet during the laying process; S58. Make a vacuum bag and use the vacuum bag to pressurize the repair area.

[0036] like Figure 1 As shown, the composite engine housing with R-angle prefabricated parts bonded together is transferred to an autoclave for heating and pressurization curing.

[0037] like Figure 3 As shown, the specific steps include: S61, transferring the bonded shell into an autoclave; S62, checking the airtightness of the vacuum bag, the airtightness requirement is that the vacuum degree is not greater than -95KPa, and the pressure drop within 2 minutes after the vacuum connection is turned off does not exceed 5KPa; S63, heating and pressurizing the bonded shell for curing.

[0038] like Figure 1 As shown, the repaired area is sanded to create a smooth transition, and then a quality inspection is performed.

[0039] like Figure 3 As shown, the specific steps include: S71, after curing, remove the vacuum bag-like auxiliary material at the shell repair location; S72, smooth the shell repair location; S73, perform size, appearance, and non-destructive testing on the shell repair location.

[0040] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0041] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for repairing R-corner defects in the thermal insulation structure of a composite engine casing, characterized in that, The method for repairing R-angle defects includes the following steps: S1. Two R-angle preforms are prepared by molding. S2. Cut and grind the two R-angle prefabricated parts obtained in S1. S21. Cut a whole circular R-corner precast part into two halves along a 30° angle, and number them 1# and 2# respectively. At the same time, cut another whole circular R-corner precast part into a R-corner precast part with a length of not less than 150mm along a 30° angle, and number it 3#. S22. Grind the cutting positions of #1 and #2 so that the cutting positions of the R-angle precast parts of #1 and #2 can overlap by 15~20mm; S3. Test fit the pre-made R-corner component after cutting and grinding with the R-corner defect location to be repaired; S31. Roughen the bonding surfaces of the No. 1, No. 2 and No. 3 R-angle preforms, the bonding surfaces of the 0.5mm calcined rubber sheet, and the defective locations of the shell insulation structure by grinding, and clean the grinding surfaces with solvent. S32. Fix a 0.5mm thick sheet of unadhesive rubber to the defect location of the shell insulation structure, and mark the position of the rubber sheet by drawing a line at the defect location of the shell insulation structure. S33. Place the #1 R corner preform at the defect location of the shell insulation structure where the rubber sheet has been applied for trial fitting, and observe the fit between the #1 R corner preform and the defect location of the shell insulation structure from the side. Mark the trial fitting position of the #1 R corner preform at the defect location of the shell insulation structure. S34. Similarly, trial fitting of the 2#R corner prefabricated component is carried out, and the trial fitting position of the 2#R corner prefabricated component is marked by drawing a line at the defect location of the shell insulation structure. S35. Trial fitting of the 3#R-angle precast component. During the trial fitting process, fix the 1#R-angle precast component and the 2#R-angle precast component at the defect position of the shell insulation structure, and grind both ends of the 3#R-angle precast component so that the cut of the 3#R-angle precast component can overlap with the 1#R-angle precast component and the 2#R-angle precast component by 15~20mm, so that the 1#R-angle precast component, the 2#R-angle precast component and the 3#R-angle precast component can be spliced ​​into a spliced ​​whole round R-angle precast component; S36. After the trial fitting is completed, mark the trial fitting position of the spliced ​​round R-corner prefabricated parts at the defect location of the shell insulation structure; S4. Dry the precast R-angle parts used for repair and the shell to be repaired; S5. Use adhesive to bond the R-corner prefabricated part to the R-corner defect to be repaired; S6. Transfer the composite engine housing with the R-angle prefabricated parts bonded to the autoclave for heating and pressurization curing; S7. Grind the repaired area to create a smooth transition and then perform a quality inspection.

2. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 1, characterized in that, The molding method in S1 includes the following steps: S11. Mold cleaning: Use solvent to clean the surface of the molding die and spray a Teflon coating on the mold surface. S12, Filler: Cut the uncured heat insulation rubber sheet into the required size and lay the cut heat insulation rubber sheet into the molding die in sequence. S13. Compression molding: The compression mold is closed, and a thermocouple is installed inside the compression mold. The closed compression mold is then transferred to a press for heating and pressurization vulcanization molding. S14. Demolding inspection: Demold the R-angle preform after vulcanization and perform appearance, dimensional and damage inspection.

3. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 2, characterized in that, The insulating rubber sheet is a nitrile rubber sheet, and the weight of the nitrile rubber sheet is 10% to 15% more than the theoretical weight of the R-angle preform.

4. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 2, characterized in that, The temperature of the thermocouple in S13 is ≤150℃, the heating and cooling rate of the thermocouple does not exceed 2℃ / min, and the pressure of the press is ≤150 tons.

5. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 4, characterized in that, S4 specifically includes the following steps: S41. Clean the prefabricated 1#, 2#, and 3# R-angle components, 0.5mm calcined rubber sheet, and the defective areas of the shell insulation structure. S42. Place the cleaned #1, #2, and #3 R-angle preforms, 0.5mm calcined rubber sheets, and the defective locations of the shell insulation structure into an oven and pre-dry them at 80°C.

6. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 5, characterized in that, S5 specifically includes the following steps: S51. Prepare the adhesive according to the adhesive mixing ratio; S52. Lay a 0.5mm thick sheet of calcined rubber around the defect in the insulation structure of the shell, and apply adhesive to the calcined rubber sheet and the defect in the insulation structure of the shell. S53. Use a vacuum bag to cold press the molten rubber sheet. After cold pressing, grind the edges of the molten rubber sheet to transition. S54. Place the #1 R corner preform again at the defect location of the shell insulation structure where the cured rubber sheet has been laid, and observe the fit between the #1 R corner preform and the defect location of the shell insulation structure to determine if the #1 R corner preform is suitable for trial fitting. S55. Trial fit the precast components of R-angle 2# and 3# again using the above method, and confirm that the cuts of the precast components of R-angle 1#, 2# and 3# can overlap each other by 15~20mm, and that the precast components of R-angle 1#, 2# and 3# can be spliced ​​into a complete circle. S56. Lay the #1, #2, and #3 R-angle prefabricated parts sequentially to the marked positions of the defects in the shell insulation structure. Apply adhesive to the bonding surfaces of the #1, #2, and #3 R-angle prefabricated parts during the laying process. S57. Lay a 0.5mm thick sheet of calcined rubber over the entire repair area. The area covered by the sheet should be 10-15mm larger than the surrounding area of ​​the repair area. Apply adhesive to the bonding surface of the calcined rubber sheet during the laying process. S58. Vacuum bags are used to pressurize the repair area.

7. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 1, characterized in that, S6 specifically includes the following steps: S61. Transfer the bonded shell into the autoclave. S62. Check the airtightness of the vacuum bag; S63. The bonded shell is cured by heating and pressurizing.

8. The method for repairing R-angle defects in the thermal insulation structure of a composite engine casing according to claim 1, characterized in that, S7 specifically includes the following steps: S71. After curing, remove the vacuum bag-like auxiliary materials from the shell repair area; S72. Smooth the repaired area on the casing; S73. Perform dimensional, visual, and non-destructive testing on the repaired area of ​​the casing.

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