Airplane composite heat insulation plate based on welding forming, flap lower wall plate and assembling method

Abstract

The invention provides an aircraft composite heat insulation plate based on welding forming, a flap lower wall plate and an assembling method, and the aircraft composite heat insulation plate based on welding forming comprises an upper frame and a lower frame which are sequentially stacked to form a frame assembly; the outer edge of the outer skin and the frame assembly are aligned and stacked, the lower surface of the outer skin abuts against the lower frame, and the upper frame, the lower frame and the outer skin are formed at a time in a welding mode; the aerogel layer is arranged on the lower surface of the outer skin and located in the frame assembly. The invention has the beneficial effects that the nano porous structure of the aerogel limits the motion of gas molecules and reduces convective heat transfer, and the complex nano skeleton increases the heat conduction path, improves the heat radiation absorption, reduces the solid heat conduction and radiative heat transfer, and can tolerate the high temperature of 650 DEG C in the jet flow area of an engine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aeronautical thermal protection and lightweight structure, and particularly relates to a composite heat insulation plate of an airplane based on welding forming, a flap lower wall plate and an assembling method. BACKGROUND

[0002] Generally, the engine outer flame temperature can reach 1200-1500 DEG C, the flap lower wall plate needs to bear periodic thermal shock because of being close to the engine inlet, and the flap interacts with the engine airflow when moving. Therefore, the heat insulation plate needs to have the ability to resist the aerodynamic load.

[0003] However, the traditional wing heat insulation plate has the following problems: 1. Complex welding process: titanium alloy welding is prone to errors, and the compatibility of multiple grades of titanium alloy welding is poor; 2. Insufficient bearing capacity: single aerogel strength is insufficient and cannot bear excessive aerodynamic load; 3. Weak connection reliability: the traditional fastener connection method is prone to looseness. SUMMARY

[0004] Therefore, the present application provides a composite heat insulation plate of an airplane based on welding forming, a flap lower wall plate and an assembling method to solve the above problems.

[0005] The present application provides the following technical scheme: a composite heat insulation plate of an airplane based on welding forming, comprising: an upper frame and a lower frame, which are sequentially stacked and form a frame assembly; an outer skin, the outer edge of which is aligned with the frame assembly and is stacked, the lower surface of the outer skin abuts against the lower frame, and the upper frame, the lower frame and the outer skin are integrally formed by welding; an aerogel layer, which is arranged on the lower surface of the outer skin and located inside the frame assembly.

[0006] A flap lower wall plate comprises the above-mentioned composite heat insulation plate of an airplane based on welding forming.

[0007] An assembling method for assembling the flap lower wall plate comprises the following steps: sequentially stacking the upper frame, the lower frame and the outer skin and integrally forming by laser beam welding; pasting the aerogel layer on the lower surface of the outer skin by high-temperature-resistant organic silicone sealant; welding the gasket on the upper surface of the outer skin, perforating the aerogel layer at the position of the gasket, and placing the gasket in the perforation and welding with the lower surface of the outer skin, thereby forming the composite heat insulation plate of an airplane based on welding forming; fixing the composite heat insulation plate of an airplane based on welding forming at the honeycomb recessed nut by bolts.

[0008] Compared with the prior art, the at least one technical scheme adopted by the application can achieve the beneficial effects at least including: 1. Lightweight: The combination of TC1 outer skin and TC4 frame reduces the weight of the shell by 40% compared with traditional metal structures.

[0009] 2. High thermal insulation: The nanoscale porous structure of aerogel limits the movement of gas molecules, reduces convective heat transfer, increases the heat conduction path of the complex nanoskeleton, and improves heat radiation absorption, reducing solid heat conduction and radiation heat transfer, and can withstand high temperature of 650℃ in the engine jet area.

[0010] 3. High bearing and anti-deformation: The tensile strength of TC4 frame combined with the design of honeycomb nut improves the connection stiffness.

[0011] 4. Anti-loose design: The bolt uses a cross groove 100° countersunk titanium alloy bolt, and the nut uses a self-locking nut embedded in a blind hole of a honeycomb structure, which cooperates with the pre-tightening force control to improve the anti-loose ability in high temperature environment, and uses wet assembly.

[0012] 5. Thin thickness: Only 3mm more than the theoretical wing shape, little effect on the aerodynamic shape of the wing.

[0013] 6. Strong corrosion resistance: Titanium alloy is less affected by environmental corrosion than other aluminum alloys. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0015] Figure 1 is a schematic view of the heat insulation plate from below; Figure 2 is a welding diagram of the upper and lower frames and the outer skin; Figure 3 is a schematic view of the shell structure and aerogel assembly; Figure 4 is a schematic view of the outer skin, pad, gasket, and aerogel assembly; Figure 5 is a schematic view of the bolt connection of the heat insulation plate at the composite honeycomb sandwich wallboard.

[0016] In the drawings, the reference signs are as follows: 1, outer skin; 2, upper frame; 3, lower frame; 4, pad; 5, aerogel layer; 51, aerogel body; 52, adhesive layer; 53, glass cloth plate; 6, gasket; 71, upper composite wallboard; 72, lower composite wallboard; 73, honeycomb recessed nut; 74, honeycomb structure. DETAILED DESCRIPTION

[0017] The embodiments of the present application will be described in detail below with reference to the drawings.

[0018] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0019] As shown in Figures 1 to 4 The present application provides a composite heat insulation plate for an aircraft, the core bearing frame of which is composed of an outer skin 1, an upper edge frame 2 and a lower edge frame 3, and the integrated design of the three provides core guarantee for the structural strength and heat insulation sealing performance of the heat insulation plate. As shown in Figure 2 The upper edge frame 2 and the lower edge frame 3 are preferably made of 6061-T6 aluminum alloy or TC4 titanium alloy material. The aluminum alloy has the advantages of low density and excellent processing performance, and the titanium alloy has more excellent high-temperature resistance and oxidation resistance. The temperature resistance can be more flexibly selected according to the specific installation scene of the heat insulation plate, such as the high-temperature area of the engine compartment. Both materials are processed by precise numerical control milling to ensure that the flatness error of the edge frame is controlled within 0.05 mm. Then, the upper edge frame 2 is stacked on the lower edge frame 3 in order, to form an edge frame assembly with a thickness of 3-5 mm. The outer contour size tolerance of the edge frame assembly is strictly controlled within ±0.1 mm. The outer skin 1 is made of a high-temperature alloy sheet with a thickness of 1-2 mm. The material can maintain stable mechanical properties in a high-temperature environment of 650°C. The outer edge thereof is accurately aligned with the outer contour of the edge frame assembly, and the lower surface thereof is closely attached to the upper surface of the lower edge frame 3 after leveling with a dial gauge. The fitting gap is controlled to be within 0.03 mm. The upper edge frame 2, the lower edge frame 3 and the outer skin 1 are formed by fiber laser welding process at one time. Argon protection treatment is performed on the lap joint area before welding. The laser power is accurately controlled to be 800-1200 W, the welding speed is 5-10 mm / s, and the defocusing amount is 2-3 mm during the welding process. The continuous pulse welding mode is adopted to ensure that the weld width is uniformly controlled within 2-3 mm. The overall structure formed after welding is verified by tension test, and the lap joint strength can reach more than 90% of the base material strength. The welding seam air tightness test result meets the aviation level standard requirement, and there is no leakage phenomenon.

[0020] The aerogel layer 5 as the core heat insulation unit is closely arranged on the lower surface of the outer skin 1, and the coverage range thereof completely matches the effective area inside the edge frame assembly, so that there is no heat insulation blind area. As shown in Figure 3 The aerogel layer 5 adopts a composite structure design of core layer + double-sided reinforcing layer, and the specific composition is as follows: Aerogel body 51: The core selects nanoscale SiO2 aerogel material. The material is the first choice for thermal insulation materials in the aviation field due to its extremely low solid-phase and gas-phase conduction characteristics. The porosity is ≥ 90%, the pore size distribution is concentrated in 20-50 nm, the thermal conductivity is ≤ 0.02 W / (m·K), and the thickness is designed to be 2-5 mm according to the actual thermal insulation requirements, which can effectively block the heat conduction path in the high-temperature environment.

[0021] Binder layer 52: In order to ensure the long-term reliable bonding of the aerogel layer and the adjacent structure, a high-temperature resistant organic silicone sealant with a temperature resistance range of -60°C to 400°C is selected. The sealant is uniformly coated on both sides of the aerogel body 51 by a doctor blade. The coating thickness is strictly controlled within 0.1-0.3 mm to avoid the overflow of the binder due to excessive coating or the poor bonding caused by the too thin coating.

[0022] Glass cloth plate 53: An alkali-free glass fiber cloth treated with a surface coupling agent is pressed to form a glass cloth plate. The areal density of the glass cloth plate is 200-300 g / m², and the thickness is 0.5-1 mm. The glass cloth plate is tightly combined with the aerogel body 51 through the binder layer 52. This design can increase the shear strength of the aerogel layer to more than 1.5 MPa, effectively solving the problem of poor mechanical properties of pure aerogel materials. During assembly, the outer edge of the aerogel layer 5 is positioned with the inner wall of the frame assembly by a special tool to ensure tight abutment without gaps. The outer surface of the aerogel layer 5 is flush with the lower surface of the upper frame 2. This flush design can avoid the formation of thermal bridges at the structure junction, further improving the overall thermal insulation effect.

[0023] In order to realize reliable connection of the composite thermal insulation plate and the flap lower wall plate, and avoid the formation of local thermal bridges at the connection part, a gasket 6 and a pad 4 are arranged on the upper and lower surfaces of the outer skin 1, respectively. Both the gasket 6 and the pad 4 are made of high-temperature alloy materials consistent with the outer skin 1, ensuring that the thermal expansion coefficients are matched and reducing temperature stress. The rectangular gasket 6 welded on the upper surface of the outer skin 1 has a size of 15 mm×10 mm×2 mm, and a through hole with a diameter matching the connecting bolt is arranged at the center of the gasket 6. The gasket 6 increases the contact area between the bolt and the outer skin, avoiding deformation of the outer skin due to excessive local pressure when tightening the bolt. The cylindrical pad 4 welded on the lower surface of the outer skin 1 has a diameter of 5-10 mm, and the height is matched with the thickness of the aerogel layer 5 to ensure that the top of the pad is flush with the lower surface of the aerogel layer 5. Figure 4As shown, the aerogel layer 5 requires precise through-holes at the corresponding positions of the pad 4. The diameter of the through-hole is 0.2-0.3 mm larger than the diameter of the pad. This gap design facilitates the smooth insertion of the pad while preventing excessive heat leakage due to excessive gap. After the pad 4 is inserted into the through-hole, it is fixed to the lower surface of the outer skin 1 using resistance spot welding. The welding parameters are set to a welding current of 800-1000A, a welding time of 50-80ms, and a weld spacing of 5-8mm, forming a uniformly distributed ring of weld points. After welding, the weld points need to be ground to ensure a smooth surface without protrusions. At the same time, welding spatter and oxides are cleaned to avoid damage to the aerogel layer. This design ensures that the connection strength between the pad and the outer skin is ≥5kN, while minimizing the impact on the overall thermal insulation performance of the aerogel layer.

[0024] like Figure 5 As shown, the lower flap panel, as a key load-bearing component of the aircraft flap system, must simultaneously meet the requirements of lightweight, high strength, and structural stability. Its main structure consists of an upper composite panel 71, a lower composite panel 72, and an intermediate support structure. Both the upper composite panel 71 and the lower composite panel 72 adopt a sandwich structure of "carbon fiber reinforced resin matrix composite (CFRP) + aluminum alloy sheet." The CFRP layer is made of T800 grade carbon fiber and epoxy resin, with a thickness of 3-4 mm. The aluminum alloy sheet is 1 mm thick. Integrated composite construction is achieved through autoclave molding. The specific strength of this structure can reach 200 MPa·kg⁻¹·m³, far exceeding that of traditional metal materials. The two panels are arranged parallel to each other with a spacing of 20-30 mm as designed. The spacing is precisely controlled by dedicated positioning posts to ensure a parallelism error ≤0.1 mm / m. Figure 5 As shown, to achieve a reliable connection with the composite insulation panel and improve the overall rigidity of the wall panel, honeycomb recessed nuts 73 are uniformly embedded between the two wall panels. The nuts are made of high-strength titanium alloy with a thread precision of 5H grade to ensure a good fit with the bolts. The outer periphery of the honeycomb recessed nuts 73 tightly wraps the honeycomb structure 74. The honeycomb structure is made of aramid paper or aluminum alloy foil with a thickness of 0.03-0.05mm. The side length of the honeycomb core is designed as a regular hexagonal structure of 3-5mm. This structure can provide maximum support rigidity with minimal weight. Tests have shown that the surface compressive strength of the honeycomb structure can reach more than 5MPa, effectively improving the overall load-bearing capacity of the wall panel under the flap.

[0025] The connection between the composite insulation panel and the lower flap panel adopts a "bolt fastening + double positioning" method to ensure reliable connection and unaffected insulation performance. Specifically, aerospace-grade high-strength stainless steel bolts with a strength grade of 12.9 are used. The bolts pass sequentially through the washer 6 on the upper surface of the outer skin 1, the outer skin 1 body, and the pad 4 on the lower surface, finally achieving a precise threaded connection with the honeycomb recessed nut 73. For example... Figure 5As shown, the arrangement of bolts adopts the principle of "uniform symmetry", the pitch is designed to be 50-80 mm, and is uniformly distributed around the frame assembly and the middle stress area to ensure uniform load transmission. In order to avoid over-tightening or under-tightening during the tightening process of the bolts, a torque wrench is used to strictly control the tightening torque within the range of 8-12 N·m. After tightening, a line mark is used to ensure that the subsequent use process can be intuitively checked whether the bolts are loose. In terms of heat insulation performance, the gap between the gasket 4 and the aerogel layer 5 is strictly controlled to be ≤0.5 mm, and the gap is filled with high-temperature resistant sealant to further block the path of heat transmission through the gap; at the same time, the welding part of the gasket 6 and the outer skin 1 is brushed with heat insulation paint, the coating thickness is 0.5 mm, and the thermal conductivity is ≤0.03 W / (m·K). Through the above design, combined with the low thermal conductivity of the aerogel layer itself, the thermal bridge effect of the bolt connection part can be effectively blocked, and the integrity of the overall thermal insulation system can be ensured.

[0026] Assembly method implementation steps 1. After the upper frame 2, the lower frame 3 and the outer skin 1 are processed and formed, the size is rechecked according to the design drawing requirements, and after ensuring that the key size tolerance meets the requirements, acetone solution is used to ultrasonically clean the lap surfaces of each part, the cleaning time is 15 minutes, the surface oil, scale and impurities are removed, and then it is placed in a 120°C oven for drying for 30 minutes to ensure that the surface is dry and free of residues. After cleaning, the three are placed on a special welding tooling table, precise positioning is achieved through tooling clamps, the outer edge of the outer skin 1 is aligned with the outer edge of the frame assembly with a deviation of ≤0.1 mm, and the lower surface of the outer skin 1 is tightly attached to the upper surface of the lower frame 3 without gap; 2. A power-adjustable fiber laser welding machine is selected, and the welding parameters are set according to the material thickness: laser power 800-1200 W, welding speed 5-10 mm / s, pulse frequency 50-100 Hz, and spot diameter 0.3-0.5 mm. Pure argon with a purity of 99.99% is used as a protective gas during welding, the protective gas flow is 15-20 L / min, continuous welding is carried out along the lap edge of the frame and the outer skin, and a closed-loop continuous weld is formed. After welding, the assembly is placed in a 200°C aging furnace for 2 hours to eliminate welding stress, and then an industrial X-ray flaw detection device is used for 100% full coverage detection of the weld, the weld quality is judged according to the "Aviation and Space Welding Nondestructive Testing Standard HB / Z 65-2014", and defects such as pores, cracks and incomplete fusion are ensured to be free, and only after passing the test can it enter the next process.

[0027] 3. The bonding of the aerogel layer needs to be carried out in a dry workshop with a cleanliness level of 1000, and the environmental temperature is controlled at 20-25°C and the relative humidity is ≤50%. First, the lower surface of the outer skin 1 after welding is cleaned with anhydrous ethanol, and after the surface is naturally dried, a scraper is used to uniformly coat a high-temperature resistant silicone sealant on the lower surface of the outer skin, with a coating thickness of 0.1-0.3 mm, and the coating range is consistent with the size of the aerogel layer 5. Then the prefabricated aerogel layer 5 is smoothly laid on the coated area, and a special pressing block is used to apply a uniform pressure of 0.1-0.2 MPa to tightly bond the aerogel layer with the outer skin, while extruding the air bubbles between the layers. Then the assembly is placed in a normal temperature environment for 2-4 hours for curing, and the position of the aerogel layer is checked regularly during the curing process to ensure the accuracy of the bonding position; 4. After the aerogel layer is completely cured, according to the design position of the gasket 6 and the pad 4, high-precision numerical control milling machine or ultraviolet laser cutting equipment is used for hole processing. Before processing, the hole position is calibrated by laser positioning instrument to ensure that the hole position accuracy is controlled within ±0.2 mm. During the hole processing, the speed of the numerical control milling machine is set to 5000 r / min, the feed speed is 50 mm / min, the power of the laser cutting is set to 50 W, to avoid the aerogel layer from cracking or delaminating due to improper processing parameters. After the hole is processed, compressed air is used to blow off the aerogel debris in the hole, and special sandpaper is used to round the edges of the hole with a rounding radius of 0.5 mm to avoid stress concentration or damage to the subsequent installed pad.

[0028] 5. Place the gasket 6 on the upper surface of the outer skin 1 at the pre-set position, and fix it with a positioning tool to ensure that the center of the gasket is aligned with the subsequent bolt hole position. Use TIG welding process to weld, with the welding parameters set as follows: welding current 50-80 A, arc voltage 10-12 V, argon protection flow rate 8-10 L / min, and welding trajectory along the four corners of the gasket for spot welding fixation, with the penetration depth of each welding spot controlled at 1-1.5 mm to ensure that the gasket is firmly connected with the outer skin without welding through phenomenon. After welding, use an angle grinder to slightly polish the welding points to make the surface of the gasket smooth; 6. The prefabricated cylindrical pad 4 is inserted into the opening of the aerogel layer one by one, ensuring that the upper surface of the pad is tightly attached to the lower surface of the outer skin 1, and is positioned by magnetic positioning tool from the upper surface of the outer skin to prevent displacement of the pad during welding. Resistance spot welding process is used for welding, copper alloy electrode with a diameter of 5 mm is selected as the welding electrode, and the welding parameters are set as follows: welding current 800-1000 A, welding time 50-100 ms, electrode pressure 0.3-0.5 MPa, 4 welding points with a diameter of 2-3 mm are evenly welded in the circumferential direction of the pad. Immediately after welding, cold water is used to cool the welding area to prevent high temperature conduction to the aerogel layer and cause damage, and then a steel wire brush is used to clean the surface oxides and welding spatters to complete the assembly of the composite thermal insulation plate.

[0029] 7. The assembled composite thermal insulation plate is transported to the assembly station of the flap lower wall plate, and according to the requirements of the assembly drawing, 2-3 positioning pins are used to preliminarily fix the composite thermal insulation plate at the predetermined position of the flap lower wall plate, the diameter accuracy of the positioning pins is h6 level, ensuring that the installation position deviation of the composite thermal insulation plate is ≤0.2 mm, and at the same time, the uniformity of the gap between the composite thermal insulation plate and the wall plate is checked to ensure that there is no obvious warping or deviation; 8. Automatic drilling and riveting machine is used to install the connecting bolts one by one, and aviation-grade anti-loosening glue is applied to the threaded part before the bolt installation, then the bolt is threaded through the gasket 6, the outer skin 1, the pad 4, and the honeycomb recessed nut 73 for threaded connection. Torque wrench is used to tighten according to the principle of "symmetrical distribution and step-by-step tightening", all bolts are pre-tightened to 5 N·m first, and then tightened to the specified torque of 8-12 N·m one by one, and after tightening, the bolt head and the gasket are marked with red paint. Finally, the sealing performance of the entire connecting part is detected, helium mass spectrometer is used, the leak detection pressure is 0.1 MPa, and the leakage rate requirement is ≤1×10⁻ 9 Pa·m³ / s, ensuring that there is no air leakage and heat leakage at the connection, and the assembly of the entire flap lower wall plate is completed.

[0030] The product of the embodiment achieves the aviation level use requirements in structural strength, heat insulation performance and light weight level through the synergistic application of multiple key technologies. Among them, the laser welding process realizes the integrated forming of the frame assembly and the outer skin. Compared with the traditional riveting process, not only the structure weight is reduced by more than 15%, but also the strength of the lap joint part is improved by 20%, and the air tightness of the weld effectively avoids the infiltration of external high temperature gas into the inside; The aerogel layer adopts the composite design of "core layer + double-sided reinforcing layer", which not only retains the low thermal conductivity advantage of SiO2 aerogel, but also solves the industry problem of easy fragmentation and poor shear resistance of pure aerogel material through the reinforcing effect of glass cloth plate, so that the service life of the aerogel layer is extended to more than 10 years; The connection structure of the honeycomb nut and the bolt realizes the reliable fixation of the composite heat insulation plate, and through the lightweight design of the honeycomb structure and the thermal bridge blocking design of the pad, the load bearing performance and the heat insulation performance are considered. After testing by an authoritative third-party testing institution, the composite heat insulation plate of the embodiment can stably control the cold face temperature rise to ≤50℃ under the working condition of 300℃ high temperature continuous heating for 2 hours, which is much better than the technical index of ≤80℃ specified in the aviation field; At the same time, the specific strength of the entire flap lower wall plate reaches 180MPa·kg⁻¹·m³, which meets the requirements of the aerodynamic load and vibration of the aircraft flap system during take-off and landing. The technical scheme of the embodiment is suitable for the heat insulation protection of high temperature areas such as flaps and tail wings of various civil aviation passenger planes and military aircraft, and has a broad application prospect.

[0031] The above is only a specific embodiment of the present application, which cannot limit the scope of the application. Therefore, the replacement of equivalent components or equivalent changes and modifications made within the scope of the present application should still be within the scope of the present patent. In addition, the technical features in the present application can be freely combined with each other, and the technical features can be freely combined with each other.

Claims

1. A composite thermal panel for an aircraft based on a welded form, characterized in that, The application relates to a composite heat insulation plate for an aircraft based on welding forming. The composite heat insulation plate for the aircraft based on welding forming comprises an upper frame (2) and a lower frame (3) which are sequentially stacked and form a frame assembly; an outer skin (1) which is aligned with the frame assembly and is stacked, and the lower surface of the outer skin (1) is in abutment with the lower frame (3), and the upper frame (2), the lower frame (3) and the outer skin (1) are integrally formed by welding; and an aerogel layer (5) which is arranged on the lower surface of the outer skin (1) and is located inside the frame assembly. The composite heat insulation plate for the aircraft based on welding forming further comprises a gasket (6) which is welded to the upper surface of the outer skin (1); and a cushion block (4) which is welded to the lower surface of the outer skin (1), and the aerogel layer (5) is perforated at the position of the cushion block (4), and the cushion block (4) is located in the perforation. The aerogel layer (5) comprises an aerogel body (51), an adhesive layer (52) arranged on the two side surfaces of the aerogel body (51), and a glass cloth plate (53) arranged on the two sides of the aerogel body (51), and the glass cloth plate (53) is attached to the aerogel body (51) through the adhesive layer (52).

2. The welded-form-based aircraft composite thermal panel of claim 1, wherein, The composite heat insulation plate for the aircraft based on welding forming is the composite heat insulation plate for the aircraft based on welding forming as claimed in any one of claims 1 to 3. The flap lower wall plate comprises an upper composite wall plate (71) and a lower composite wall plate (72) which are arranged at intervals, and a honeycomb recessed nut (73) which is arranged between the upper composite wall plate (71) and the lower composite wall plate (72), and the outer periphery of the honeycomb recessed nut (73) is provided with a honeycomb structure (74). The composite heat insulation plate for the aircraft based on welding forming is fixedly connected with the honeycomb recessed nut (73) through connecting bolts which sequentially pass through the gasket (6) and the cushion block (4).

3. The welded-form-based aircraft composite thermal panel of claim 1, wherein, The method comprises the following steps: sequentially stacking the upper frame (2), the lower frame (3) and the outer skin (1) and integrally forming the same through laser beam welding; pasting the aerogel layer (5) on the lower surface of the outer skin (1) through a high-temperature-resistant organic silicone sealant; welding the gasket (6) to the upper surface of the outer skin (1), perforating the aerogel layer (5) at the position of the gasket (6), arranging the cushion block (4) in the perforation and welding the cushion block (4) to the lower surface of the outer skin (1), so as to form the composite heat insulation plate for the aircraft based on welding forming; 4. A flap lower wall panel comprising a welded-form based aircraft composite thermal panel, characterized in that, fixing the composite heat insulation plate for the aircraft based on welding forming at the honeycomb recessed nut (73) through bolts.

5. The flap lower wall panel of claim 4, wherein, The method comprises the following steps: abutting the outer edge of the aerogel layer (5) with the frame assembly and making the outer surface of the aerogel layer (5) flush with the lower surface of the upper frame (2). ​ 6. The flap lower wall panel of claim 5, wherein, ​ 7. A method of assembling a flap lower wall panel, comprising: ​ ​ ​ ​ ​ 8. The method of assembling according to claim 7, wherein, ​ ​

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