A honeycomb sandwich composite structure thermal protection material and a preparation method thereof

Abstract

The application discloses a kind of honeycomb sandwich combination structure heat protection materials and preparation method thereof, comprising the following steps: step one, pleated core preparation;Step two, pleated core and upper panel bonding;Step three, honeycomb structure preparation;Step four, honeycomb structure and pleated structure bonding;Step five, ceramic-based upper panel preparation of double-layer sandwich structure.The application combines honeycomb structure and pleated structure these two sandwich modes, makes full use of its heat insulation performance, realizes lightweight at the same time, also lays good material of high-temperature resistance to further improve the heat insulation performance of material, realizes light weight, high-temperature resistance while guaranteeing mechanical property, and the fluid channel of pleated structure can further consume heat, and then further heat insulation by honeycomb structure, to guarantee the stability of structure, and the preparation method provided by the application is simple and easy to operate.

Description

Technical Field

[0001] This invention belongs to the field of thermal protection materials technology, specifically a honeycomb sandwich composite structure thermal protection material and its preparation method. Background Technology

[0002] Hypersonic vehicles are a hot research topic in the aerospace field both domestically and internationally, and they have significant research value for politics, military affairs, and science and technology. However, in the high enthalpy, high heat flux, and long-term continuous heating service environment, intense aerodynamic heating generates extremely high temperatures, leading to ablation damage, which not only causes structural deformation but also affects the normal operation of their internal systems.

[0003] In order to obtain materials that can maintain their structural shape at high temperatures, some scholars have prepared rigid heat-resistant tiles for large-area thermal protection, but this increases the weight of the aircraft and cannot achieve lightweight and high load-bearing capacity. Other scholars have adopted a combination of active and passive protection, using a two-phase dispersion distribution of metal-ceramic matrix composites to improve the temperature limit of the material, but this method is complex and the reaction is difficult to control. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a honeycomb sandwich composite thermal protection material in order to solve the above-mentioned problems. This invention combines two sandwich structures, honeycomb structure and pleated structure, which can reduce the material weight while making full use of fluid channels to further insulate the heat and obtain a structure with high temperature resistance. Moreover, the method is simple and easy to operate.

[0005] To address the above problems, the present invention provides the following technical solution:

[0006] A method for preparing a honeycomb sandwich composite structure thermal protection material includes the following steps:

[0007] Step 1: Preparation of the pleated core:

[0008] (1) Clean the mold with acetone, brush the mold release agent on the mold surface to facilitate demolding, and preheat the mold to 35-45°C. Place the glass fiber prepreg on the surface of the female mold.

[0009] (2) Press the positive mold monomers into the negative mold one by one, and use bolts and clamping blocks to install the positive mold and glass fiber prepreg in the base;

[0010] (3) Place the mold as a whole into an oven, heat it to 122-130℃, keep it at that temperature for 0.5-1.5h, and after it solidifies, cool it to room temperature to demold it and obtain the pleated core.

[0011] Step 2: Attaching the pleated core to the top panel:

[0012] The carbon fiber preform is covered with an isolation membrane, a pressure equalizing plate, an electric heating blanket, thermal insulation cotton, and a vacuum bag. It is then sealed with sealant and vacuumed to obtain the top panel. The pleated core and the top panel are then sanded with sandpaper. The top panel and the pleated core are bonded together with epoxy resin film and cured to obtain the pleated structure. The top panel serves as the upper layer of the overall structure.

[0013] Step 3: Honeycomb structure preparation:

[0014] Phenolic resin aerogel was injected into the honeycomb core using vacuum assistance, with the vacuum level controlled at -0.1 to -0.2 MPa. The core was cured at room temperature and then dried at a supercritical temperature of 20 to 300°C to obtain the honeycomb structure.

[0015] Step 4: Bonding the honeycomb structure to the pleated structure:

[0016] Considering the bonding of the honeycomb structure and the pleated structure, compression bushings are set at the top and bottom of the honeycomb structure and glued with foam. Then, carbon fiber panels are covered on the bushings to maintain good mechanical properties of the structure. Epoxy resin film is used to glue the bottom plate of the pleated structure to obtain a double-layer sandwich structure. At the same time, carbon fiber panels are also glued to the bottom bushing of the honeycomb structure to serve as the bottom layer of the overall structure.

[0017] Step 5: Fabrication of the ceramic substrate top panel with a double-layer sandwich structure:

[0018] First, fiberglass cloth is sewn onto the upper surface of the double-layer sandwich structure, and a ceramic precursor solution is injected. After heat treatment and repeated impregnation, a ceramic base panel is obtained, and finally, the desired honeycomb sandwich composite structure thermal protection material is obtained.

[0019] Preferably, in step one, the release agent is an organosilicon release agent.

[0020] Preferably, the silicone release agent is one of dimethyl silicone oil, methylphenyl silicone oil, and diethyl silicone oil.

[0021] Preferably, in step one, the heating rate is 2-4 °C / min.

[0022] Preferably, the honeycomb core is composed of a sheet made of one of the following materials: aramid, polycarbonate, polypropylene, steel, aluminum, aluminum alloy, or glass fiber; the cross-sectional shape of each cell in the honeycomb core is hexagonal, overstretched hexagonal, circular, or corrugated; the self-expanding sealant of the honeycomb core is expanded polystyrene or expanded polyurethane; the thickness of the honeycomb core is 2–300 mm, the cell size is 1.6–20.0 mm, the cell wall thickness is 0.1–0.3 mm, and the density is 24–200 kg / m³. 3 .

[0023] Preferably, in step five, the solid content of the ceramic precursor solution is 50-60%.

[0024] Preferably, in step five, the ceramic precursor is a silicon-based ceramic precursor.

[0025] Preferably, the silicon-based ceramic precursor is one or more of polycarbosilane, polysilazane, and polyboronsilazane.

[0026] Preferably, in step five, the injection pressure is 0.1–5 MPa and the injection flow rate is 1–5 mL / s.

[0027] A honeycomb sandwich composite thermal protection material is prepared using the above-described preparation method.

[0028] The beneficial effects of this invention are:

[0029] This invention combines two sandwich structures, honeycomb structure and pleated structure, to make full use of their thermal insulation performance. While achieving lightweight, it also lays out materials with good high-temperature resistance to further improve the thermal insulation performance of the materials. While ensuring mechanical properties, it achieves lightweight and high-temperature resistance. Furthermore, the fluid channels of the pleated structure can further dissipate heat, and the honeycomb structure provides further thermal insulation to ensure the stability of the structure. Moreover, the preparation method provided by this invention is simple and easy to operate. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] A method for preparing a honeycomb sandwich composite structure thermal protection material includes the following steps:

[0033] Step 1: Preparation of the pleated core:

[0034] (1) Clean the mold with acetone, brush the mold surface with dimethyl silicone oil to facilitate demolding, preheat the mold to 35°C, and place the glass fiber prepreg on the surface of the female mold;

[0035] (2) Press the positive mold monomers into the negative mold one by one, and use bolts and clamping blocks to install the positive mold and glass fiber prepreg in the base;

[0036] (3) Place the mold into an oven and heat it to 122°C at a heating rate of 2°C / min. Keep it at that temperature for 1.5 hours. After curing, cool it to room temperature and demold to obtain the pleated core.

[0037] Step 2: Attaching the pleated core to the top panel:

[0038] The carbon fiber preform is covered with an isolation membrane, a pressure equalizing plate, an electric heating blanket, thermal insulation cotton, and a vacuum bag. It is then sealed with sealant and vacuumed to obtain the top panel. The pleated core and the top panel are then sanded with sandpaper. The top panel and the pleated core are bonded together with epoxy resin film and cured to obtain the pleated structure. The top panel serves as the upper layer of the overall structure.

[0039] Step 3: Honeycomb structure preparation:

[0040] Phenolic resin aerogel was injected into the honeycomb core using vacuum assistance, with the vacuum level controlled at -0.1 MPa. The core was cured at room temperature and then dried at a supercritical temperature of 20°C to obtain the honeycomb structure.

[0041] The honeycomb core is composed of a thin sheet made of aramid; the cross-sectional shape of each cell in the honeycomb core is hexagonal; the self-expanding sealant of the honeycomb core is expanded polystyrene; the thickness of the honeycomb core is 2 mm, the cell size is 1.6 mm, the cell wall thickness is 0.1 mm, and the density is 24 kg / m³. 3 ;

[0042] Step 4: Bonding the honeycomb structure to the pleated structure:

[0043] Considering the bonding of the honeycomb structure and the pleated structure, compression bushings are set at the top and bottom of the honeycomb structure and glued with foam. Then, carbon fiber panels are covered on the bushings to maintain good mechanical properties of the structure. Epoxy resin film is used to glue the bottom plate of the pleated structure to obtain a double-layer sandwich structure. At the same time, carbon fiber panels are also glued to the bottom bushing of the honeycomb structure to serve as the bottom layer of the overall structure.

[0044] Step 5: Fabrication of the ceramic substrate top panel with a double-layer sandwich structure:

[0045] First, fiberglass cloth is sewn onto the upper surface of the double-layer sandwich structure, and then a ceramic precursor solution is injected. The solid content of the ceramic precursor solution is 50%, the ceramic precursor is polycarbosilane, the injection pressure is 0.1 MPa, and the injection flow rate is 1 mL / s. After heat treatment and repeated impregnation, a ceramic substrate upper panel is obtained, and finally the desired honeycomb sandwich composite structure thermal protection material is obtained.

[0046] Example 2:

[0047] A method for preparing a honeycomb sandwich composite structure thermal protection material includes the following steps:

[0048] Step 1: Preparation of the pleated core:

[0049] (1) Clean the mold with acetone, brush the mold surface with methyl phenyl silicone oil to facilitate demolding, preheat the mold to 40°C, and place the glass fiber prepreg on the surface of the female mold;

[0050] (2) Press the positive mold monomers into the negative mold one by one, and use bolts and clamping blocks to install the positive mold and glass fiber prepreg in the base;

[0051] (3) Place the mold into the oven and heat it to 126°C at a heating rate of 3°C / min. Keep it at that temperature for 1 hour. After curing, cool it to room temperature and demold to obtain the pleated core.

[0052] Step 2: Attaching the pleated core to the top panel:

[0053] The carbon fiber preform is covered with an isolation membrane, a pressure equalizing plate, an electric heating blanket, thermal insulation cotton, and a vacuum bag. It is then sealed with sealant and vacuumed to obtain the top panel. The pleated core and the top panel are then sanded with sandpaper. The top panel and the pleated core are bonded together with epoxy resin film and cured to obtain the pleated structure. The top panel serves as the upper layer of the overall structure.

[0054] Step 3: Honeycomb structure preparation:

[0055] Phenolic resin aerogel was injected into the honeycomb core using vacuum assistance, with the vacuum level controlled at -0.15 MPa. The core was cured at room temperature and then dried at a supercritical temperature of 160°C to obtain the honeycomb structure.

[0056] The honeycomb core is composed of a sheet of polycarbonate; the cross-sectional shape of each cell in the honeycomb core is an overstretched hexagon; the self-expanding sealant of the honeycomb core is expanded polystyrene; the thickness of the honeycomb core is 151 mm, the cell size is 10.8 mm, the cell wall thickness is 0.2 mm, and the density is 112 kg / m³. 3 ;

[0057] Step 4: Bonding the honeycomb structure to the pleated structure:

[0058] Considering the bonding of the honeycomb structure and the pleated structure, compression bushings are set at the top and bottom of the honeycomb structure and glued with foam. Then, carbon fiber panels are covered on the bushings to maintain good mechanical properties of the structure. Epoxy resin film is used to glue the bottom plate of the pleated structure to obtain a double-layer sandwich structure. At the same time, carbon fiber panels are also glued to the bottom bushing of the honeycomb structure to serve as the bottom layer of the overall structure.

[0059] Step 5: Fabrication of the ceramic substrate top panel with a double-layer sandwich structure:

[0060] First, fiberglass cloth is sewn onto the upper surface of the double-layer sandwich structure, and then a ceramic precursor solution is injected. The solid content of the ceramic precursor solution is 55%, the ceramic precursor is polysilazane, the injection pressure is 2.6 MPa, and the injection flow rate is 3 mL / s. After heat treatment and repeated impregnation, a ceramic substrate upper panel is obtained, and finally the desired honeycomb sandwich composite structure thermal protection material is obtained.

[0061] Example 3:

[0062] A method for preparing a honeycomb sandwich composite structure thermal protection material includes the following steps:

[0063] Step 1: Preparation of the pleated core:

[0064] (1) Clean the mold with acetone, brush the mold surface with diethyl silicone oil to facilitate demolding, preheat the mold to 45°C, and place the glass fiber prepreg on the surface of the female mold;

[0065] (2) Press the positive mold monomers into the negative mold one by one, and use bolts and clamping blocks to install the positive mold and glass fiber prepreg in the base;

[0066] (3) Place the mold into an oven and heat it to 130°C at a heating rate of 4°C / min. Hold it at that temperature for 0.5 hours. After curing, cool it to room temperature and demold to obtain the pleated core.

[0067] Step 2: Attaching the pleated core to the top panel:

[0068] The carbon fiber preform is covered with an isolation membrane, a pressure equalizing plate, an electric heating blanket, thermal insulation cotton, and a vacuum bag. It is then sealed with sealant and vacuumed to obtain the top panel. The pleated core and the top panel are then sanded with sandpaper. The top panel and the pleated core are bonded together with epoxy resin film and cured to obtain the pleated structure. The top panel serves as the upper layer of the overall structure.

[0069] Step 3: Honeycomb structure preparation:

[0070] Phenolic resin aerogel was injected into the honeycomb core using vacuum assistance, with the vacuum level controlled at -0.2 MPa. The core was cured at room temperature and then dried at a supercritical temperature of 300°C to obtain the honeycomb structure.

[0071] The honeycomb core is composed of a sheet of polypropylene; the cross-sectional shape of each cell in the honeycomb core is circular; the self-expanding sealant of the honeycomb core is expanding polyurethane; the thickness of the honeycomb core is 300 mm, the cell size is 20.0 mm, the cell wall thickness is 0.3 mm, and the density is 200 kg / m³. 3 ;

[0072] Step 4: Bonding the honeycomb structure to the pleated structure:

[0073] Considering the bonding of the honeycomb structure and the pleated structure, compression bushings are set at the top and bottom of the honeycomb structure and glued with foam. Then, carbon fiber panels are covered on the bushings to maintain good mechanical properties of the structure. Epoxy resin film is used to glue the bottom plate of the pleated structure to obtain a double-layer sandwich structure. At the same time, carbon fiber panels are also glued to the bottom bushing of the honeycomb structure to serve as the bottom layer of the overall structure.

[0074] Step 5: Fabrication of the ceramic substrate top panel with a double-layer sandwich structure:

[0075] First, fiberglass cloth is sewn onto the upper surface of the double-layer sandwich structure, and then a ceramic precursor solution is injected. The solid content of the ceramic precursor solution is 60%, and the ceramic precursor is polyborosilicate. The injection pressure is 5 MPa, and the injection flow rate is 5 mL / s. After heat treatment and repeated impregnation, a ceramic substrate upper panel is obtained, and finally, the desired honeycomb sandwich composite structure thermal protection material is obtained.

[0076] At 500kw / m 2 The back temperature rise of the thermal protection materials of different thicknesses prepared in Examples 1-3 of this invention was tested under heat flow for 50 seconds to measure the heat protection effect of the thermal protection materials. At the same time, in order to prove the advantages of this invention, a comparative experiment was conducted on traditional thermal protection materials (glass fiber cloth coated with silicone rubber) of the same thickness. The test sample size was 10cm×10cm, and the test results are shown in Table 1.

[0077] Table 1

[0078]

[0079]

[0080] As can be clearly seen from Table 1, for heat-protecting materials of the same size and thickness, at 500 kW / m 2 After 50 seconds of testing, the thermal insulation effect of the thermal protection material prepared by this invention is far better than that of existing thermal protection materials.

[0081] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a honeycomb sandwich composite structure thermal protection material, characterized in that: Includes the following steps: Step 1: Preparation of the pleated core: (1) Clean the mold with acetone, brush the mold release agent on the mold surface to facilitate demolding, and preheat the mold to 35-45°C. Place the glass fiber prepreg on the surface of the female mold. (2) Press the positive mold monomer into the negative mold one by one, and use bolts and clamping blocks to install the positive mold and glass fiber prepreg in the base; (3) Place the mold in an oven, heat it to 122-130℃, keep it at that temperature for 0.5-1.5h, and after solidification, cool it to room temperature to demold and obtain the pleated core; Step 2: Attaching the pleated core to the top panel: The carbon fiber preform is covered with an isolation membrane, a pressure equalizing plate, an electric heating blanket, thermal insulation cotton, and a vacuum bag. It is then sealed with sealant and vacuumed to obtain the top panel. The pleated core and the top panel are then sanded with sandpaper. The top panel and the pleated core are bonded together with epoxy resin film and cured to obtain the pleated structure. The top panel serves as the upper layer of the overall structure. Step 3: Cellular structure preparation: Phenolic resin aerogel was injected into the honeycomb core using vacuum assistance, with the vacuum level controlled at -0.1 MPa. The core was cured at room temperature and then dried at a supercritical temperature of 20–300°C to obtain the honeycomb structure. Step 4: Bonding the honeycomb structure to the pleated structure: Considering the bonding of the honeycomb structure and the pleated structure, compression bushings are set at the top and bottom of the honeycomb structure and glued with foam. Then, carbon fiber panels are covered on the bushings to maintain good mechanical properties of the structure. Epoxy resin film is used to glue the bottom plate of the pleated structure to obtain a double-layer sandwich structure. At the same time, carbon fiber panels are also glued to the bottom bushing of the honeycomb structure to serve as the bottom layer of the overall structure. Step 5: Fabrication of the ceramic substrate top panel with a double-layer sandwich structure: First, fiberglass cloth is sewn onto the upper surface of the double-layer sandwich structure, and ceramic precursor solution is injected. After heat treatment and repeated impregnation, a ceramic base panel is obtained, and finally the desired honeycomb sandwich composite structure thermal protection material is obtained. In step three, the honeycomb core is composed of a thin sheet made of one of the following materials: aramid, polycarbonate, polypropylene, steel, aluminum, aluminum alloy, or glass fiber; the cross-sectional shape of each cell in the honeycomb core is hexagonal, overstretched hexagonal, circular, or corrugated; the self-expanding sealant of the honeycomb core is expanded polystyrene or expanded polyurethane; the thickness of the honeycomb core is 2–300 mm, the cell size is 1.6–20.0 mm, the cell wall thickness is 0.1–0.3 mm, and the density is 24–200 kg / m³. 3 .

2. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 1, characterized in that: In step one, an organosilicon release agent is selected as the release agent.

3. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 2, characterized in that: The silicone release agent is one of dimethyl silicone oil, methylphenyl silicone oil, and diethyl silicone oil.

4. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 1, characterized in that: In step one, the heating rate is 2-4℃ / min.

5. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 1, characterized in that: In step five, the solid content of the ceramic precursor solution is 50-60%.

6. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 5, characterized in that: In step five, the ceramic precursor is selected as a silicon-based ceramic precursor.

7. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 6, characterized in that: The silicon-based ceramic precursor is one or more of polycarbosilane, polysilazane, and polyboronsilazane.

8. The method for preparing a honeycomb sandwich composite structure thermal protection material according to claim 1, characterized in that: In step five, the injection pressure is 0.1–5 MPa and the injection flow rate is 1–5 mL / s.

9. A honeycomb sandwich composite structure thermal protection material, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 8.

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